1 | =head1 => NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - the DBI of event loop programming |
4 | |
4 | |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt |
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6 | and POE are various supported event loops/environments. |
6 | |
7 | |
7 | =head1 SYNOPSIS |
8 | =head1 SYNOPSIS |
8 | |
9 | |
9 | use AnyEvent; |
10 | use AnyEvent; |
10 | |
11 | |
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12 | # if you prefer function calls, look at the AE manpage for |
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13 | # an alternative API. |
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14 | |
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15 | # file handle or descriptor readable |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
16 | my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); |
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17 | |
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18 | # one-shot or repeating timers |
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19 | my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); |
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20 | my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...); |
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21 | |
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22 | print AnyEvent->now; # prints current event loop time |
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23 | print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. |
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24 | |
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25 | # POSIX signal |
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26 | my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); |
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27 | |
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28 | # child process exit |
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29 | my $w = AnyEvent->child (pid => $pid, cb => sub { |
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30 | my ($pid, $status) = @_; |
12 | ... |
31 | ... |
13 | }); |
32 | }); |
14 | |
33 | |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
34 | # called when event loop idle (if applicable) |
16 | ... |
35 | my $w = AnyEvent->idle (cb => sub { ... }); |
17 | }); |
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18 | |
36 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
37 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
20 | $w->send; # wake up current and all future recv's |
38 | $w->send; # wake up current and all future recv's |
21 | $w->recv; # enters "main loop" till $condvar gets ->send |
39 | $w->recv; # enters "main loop" till $condvar gets ->send |
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40 | # use a condvar in callback mode: |
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41 | $w->cb (sub { $_[0]->recv }); |
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42 | |
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43 | =head1 INTRODUCTION/TUTORIAL |
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44 | |
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45 | This manpage is mainly a reference manual. If you are interested |
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46 | in a tutorial or some gentle introduction, have a look at the |
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47 | L<AnyEvent::Intro> manpage. |
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48 | |
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49 | =head1 SUPPORT |
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50 | |
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51 | An FAQ document is available as L<AnyEvent::FAQ>. |
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52 | |
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53 | There also is a mailinglist for discussing all things AnyEvent, and an IRC |
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54 | channel, too. |
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55 | |
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56 | See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software |
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57 | Repository>, at L<http://anyevent.schmorp.de>, for more info. |
22 | |
58 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
59 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
60 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
61 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
62 | nowadays. So what is different about AnyEvent? |
27 | |
63 | |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
64 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
29 | policy> and AnyEvent is I<small and efficient>. |
65 | policy> and AnyEvent is I<small and efficient>. |
30 | |
66 | |
31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
67 | First and foremost, I<AnyEvent is not an event model> itself, it only |
32 | interfaces to whatever event model the main program happens to use in a |
68 | interfaces to whatever event model the main program happens to use, in a |
33 | pragmatic way. For event models and certain classes of immortals alike, |
69 | pragmatic way. For event models and certain classes of immortals alike, |
34 | the statement "there can only be one" is a bitter reality: In general, |
70 | the statement "there can only be one" is a bitter reality: In general, |
35 | only one event loop can be active at the same time in a process. AnyEvent |
71 | only one event loop can be active at the same time in a process. AnyEvent |
36 | helps hiding the differences between those event loops. |
72 | cannot change this, but it can hide the differences between those event |
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73 | loops. |
37 | |
74 | |
38 | The goal of AnyEvent is to offer module authors the ability to do event |
75 | The goal of AnyEvent is to offer module authors the ability to do event |
39 | programming (waiting for I/O or timer events) without subscribing to a |
76 | programming (waiting for I/O or timer events) without subscribing to a |
40 | religion, a way of living, and most importantly: without forcing your |
77 | religion, a way of living, and most importantly: without forcing your |
41 | module users into the same thing by forcing them to use the same event |
78 | module users into the same thing by forcing them to use the same event |
42 | model you use. |
79 | model you use. |
43 | |
80 | |
44 | For modules like POE or IO::Async (which is a total misnomer as it is |
81 | For modules like POE or IO::Async (which is a total misnomer as it is |
45 | actually doing all I/O I<synchronously>...), using them in your module is |
82 | actually doing all I/O I<synchronously>...), using them in your module is |
46 | like joining a cult: After you joined, you are dependent on them and you |
83 | like joining a cult: After you join, you are dependent on them and you |
47 | cannot use anything else, as it is simply incompatible to everything that |
84 | cannot use anything else, as they are simply incompatible to everything |
48 | isn't itself. What's worse, all the potential users of your module are |
85 | that isn't them. What's worse, all the potential users of your |
49 | I<also> forced to use the same event loop you use. |
86 | module are I<also> forced to use the same event loop you use. |
50 | |
87 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
88 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
89 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
53 | with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if |
90 | with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if |
54 | your module uses one of those, every user of your module has to use it, |
91 | your module uses one of those, every user of your module has to use it, |
55 | too. But if your module uses AnyEvent, it works transparently with all |
92 | too. But if your module uses AnyEvent, it works transparently with all |
56 | event models it supports (including stuff like POE and IO::Async, as long |
93 | event models it supports (including stuff like IO::Async, as long as those |
57 | as those use one of the supported event loops. It is trivial to add new |
94 | use one of the supported event loops. It is easy to add new event loops |
58 | event loops to AnyEvent, too, so it is future-proof). |
95 | to AnyEvent, too, so it is future-proof). |
59 | |
96 | |
60 | In addition to being free of having to use I<the one and only true event |
97 | In addition to being free of having to use I<the one and only true event |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
98 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
62 | modules, you get an enourmous amount of code and strict rules you have to |
99 | modules, you get an enormous amount of code and strict rules you have to |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
100 | follow. AnyEvent, on the other hand, is lean and to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
101 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
102 | technically possible. |
66 | |
103 | |
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104 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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105 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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106 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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107 | such as Windows) and lots of real-world knowledge and workarounds for |
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108 | platform bugs and differences. |
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109 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
110 | Now, if you I<do want> lots of policy (this can arguably be somewhat |
68 | useful) and you want to force your users to use the one and only event |
111 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
112 | model, you should I<not> use this module. |
70 | |
113 | |
71 | =head1 DESCRIPTION |
114 | =head1 DESCRIPTION |
72 | |
115 | |
73 | L<AnyEvent> provides an identical interface to multiple event loops. This |
116 | L<AnyEvent> provides a uniform interface to various event loops. This |
74 | allows module authors to utilise an event loop without forcing module |
117 | allows module authors to use event loop functionality without forcing |
75 | users to use the same event loop (as only a single event loop can coexist |
118 | module users to use a specific event loop implementation (since more |
76 | peacefully at any one time). |
119 | than one event loop cannot coexist peacefully). |
77 | |
120 | |
78 | The interface itself is vaguely similar, but not identical to the L<Event> |
121 | The interface itself is vaguely similar, but not identical to the L<Event> |
79 | module. |
122 | module. |
80 | |
123 | |
81 | During the first call of any watcher-creation method, the module tries |
124 | During the first call of any watcher-creation method, the module tries |
82 | to detect the currently loaded event loop by probing whether one of the |
125 | to detect the currently loaded event loop by probing whether one of the |
83 | following modules is already loaded: L<EV>, |
126 | following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>, |
84 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
127 | L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one |
85 | L<POE>. The first one found is used. If none are found, the module tries |
128 | found is used. If none are detected, the module tries to load the first |
86 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
129 | four modules in the order given; but note that if L<EV> is not |
87 | adaptor should always succeed) in the order given. The first one that can |
130 | available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so |
88 | be successfully loaded will be used. If, after this, still none could be |
131 | the other two are not normally tried. |
89 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
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90 | very efficient, but should work everywhere. |
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91 | |
132 | |
92 | Because AnyEvent first checks for modules that are already loaded, loading |
133 | Because AnyEvent first checks for modules that are already loaded, loading |
93 | an event model explicitly before first using AnyEvent will likely make |
134 | an event model explicitly before first using AnyEvent will likely make |
94 | that model the default. For example: |
135 | that model the default. For example: |
95 | |
136 | |
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97 | use AnyEvent; |
138 | use AnyEvent; |
98 | |
139 | |
99 | # .. AnyEvent will likely default to Tk |
140 | # .. AnyEvent will likely default to Tk |
100 | |
141 | |
101 | The I<likely> means that, if any module loads another event model and |
142 | The I<likely> means that, if any module loads another event model and |
102 | starts using it, all bets are off. Maybe you should tell their authors to |
143 | starts using it, all bets are off - this case should be very rare though, |
103 | use AnyEvent so their modules work together with others seamlessly... |
144 | as very few modules hardcode event loops without announcing this very |
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145 | loudly. |
104 | |
146 | |
105 | The pure-perl implementation of AnyEvent is called |
147 | The pure-perl implementation of AnyEvent is called |
106 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
148 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
107 | explicitly. |
149 | explicitly and enjoy the high availability of that event loop :) |
108 | |
150 | |
109 | =head1 WATCHERS |
151 | =head1 WATCHERS |
110 | |
152 | |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
153 | AnyEvent has the central concept of a I<watcher>, which is an object that |
112 | stores relevant data for each kind of event you are waiting for, such as |
154 | stores relevant data for each kind of event you are waiting for, such as |
113 | the callback to call, the filehandle to watch, etc. |
155 | the callback to call, the file handle to watch, etc. |
114 | |
156 | |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
157 | These watchers are normal Perl objects with normal Perl lifetime. After |
116 | creating a watcher it will immediately "watch" for events and invoke the |
158 | creating a watcher it will immediately "watch" for events and invoke the |
117 | callback when the event occurs (of course, only when the event model |
159 | callback when the event occurs (of course, only when the event model |
118 | is in control). |
160 | is in control). |
119 | |
161 | |
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162 | Note that B<callbacks must not permanently change global variables> |
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163 | potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< |
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164 | callbacks must not C<die> >>. The former is good programming practice in |
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165 | Perl and the latter stems from the fact that exception handling differs |
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166 | widely between event loops. |
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167 | |
120 | To disable the watcher you have to destroy it (e.g. by setting the |
168 | To disable a watcher you have to destroy it (e.g. by setting the |
121 | variable you store it in to C<undef> or otherwise deleting all references |
169 | variable you store it in to C<undef> or otherwise deleting all references |
122 | to it). |
170 | to it). |
123 | |
171 | |
124 | All watchers are created by calling a method on the C<AnyEvent> class. |
172 | All watchers are created by calling a method on the C<AnyEvent> class. |
125 | |
173 | |
126 | Many watchers either are used with "recursion" (repeating timers for |
174 | Many watchers either are used with "recursion" (repeating timers for |
127 | example), or need to refer to their watcher object in other ways. |
175 | example), or need to refer to their watcher object in other ways. |
128 | |
176 | |
129 | An any way to achieve that is this pattern: |
177 | One way to achieve that is this pattern: |
130 | |
178 | |
131 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
179 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
132 | # you can use $w here, for example to undef it |
180 | # you can use $w here, for example to undef it |
133 | undef $w; |
181 | undef $w; |
134 | }); |
182 | }); |
135 | |
183 | |
136 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
184 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
137 | my variables are only visible after the statement in which they are |
185 | my variables are only visible after the statement in which they are |
138 | declared. |
186 | declared. |
139 | |
187 | |
140 | =head2 I/O WATCHERS |
188 | =head2 I/O WATCHERS |
141 | |
189 | |
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190 | $w = AnyEvent->io ( |
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191 | fh => <filehandle_or_fileno>, |
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192 | poll => <"r" or "w">, |
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193 | cb => <callback>, |
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194 | ); |
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195 | |
142 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
196 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
143 | with the following mandatory key-value pairs as arguments: |
197 | with the following mandatory key-value pairs as arguments: |
144 | |
198 | |
145 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch |
199 | C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch |
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200 | for events (AnyEvent might or might not keep a reference to this file |
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201 | handle). Note that only file handles pointing to things for which |
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202 | non-blocking operation makes sense are allowed. This includes sockets, |
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203 | most character devices, pipes, fifos and so on, but not for example files |
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204 | or block devices. |
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205 | |
146 | for events. C<poll> must be a string that is either C<r> or C<w>, |
206 | C<poll> must be a string that is either C<r> or C<w>, which creates a |
147 | which creates a watcher waiting for "r"eadable or "w"ritable events, |
207 | watcher waiting for "r"eadable or "w"ritable events, respectively. |
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208 | |
148 | respectively. C<cb> is the callback to invoke each time the file handle |
209 | C<cb> is the callback to invoke each time the file handle becomes ready. |
149 | becomes ready. |
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150 | |
210 | |
151 | Although the callback might get passed parameters, their value and |
211 | Although the callback might get passed parameters, their value and |
152 | presence is undefined and you cannot rely on them. Portable AnyEvent |
212 | presence is undefined and you cannot rely on them. Portable AnyEvent |
153 | callbacks cannot use arguments passed to I/O watcher callbacks. |
213 | callbacks cannot use arguments passed to I/O watcher callbacks. |
154 | |
214 | |
155 | The I/O watcher might use the underlying file descriptor or a copy of it. |
215 | The I/O watcher might use the underlying file descriptor or a copy of it. |
156 | You must not close a file handle as long as any watcher is active on the |
216 | You must not close a file handle as long as any watcher is active on the |
157 | underlying file descriptor. |
217 | underlying file descriptor. |
158 | |
218 | |
159 | Some event loops issue spurious readyness notifications, so you should |
219 | Some event loops issue spurious readiness notifications, so you should |
160 | always use non-blocking calls when reading/writing from/to your file |
220 | always use non-blocking calls when reading/writing from/to your file |
161 | handles. |
221 | handles. |
162 | |
222 | |
163 | Example: |
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164 | |
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165 | # wait for readability of STDIN, then read a line and disable the watcher |
223 | Example: wait for readability of STDIN, then read a line and disable the |
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224 | watcher. |
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225 | |
166 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
226 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
167 | chomp (my $input = <STDIN>); |
227 | chomp (my $input = <STDIN>); |
168 | warn "read: $input\n"; |
228 | warn "read: $input\n"; |
169 | undef $w; |
229 | undef $w; |
170 | }); |
230 | }); |
171 | |
231 | |
172 | =head2 TIME WATCHERS |
232 | =head2 TIME WATCHERS |
173 | |
233 | |
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234 | $w = AnyEvent->timer (after => <seconds>, cb => <callback>); |
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235 | |
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236 | $w = AnyEvent->timer ( |
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237 | after => <fractional_seconds>, |
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238 | interval => <fractional_seconds>, |
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239 | cb => <callback>, |
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240 | ); |
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241 | |
174 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
242 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
175 | method with the following mandatory arguments: |
243 | method with the following mandatory arguments: |
176 | |
244 | |
177 | C<after> specifies after how many seconds (fractional values are |
245 | C<after> specifies after how many seconds (fractional values are |
178 | supported) the callback should be invoked. C<cb> is the callback to invoke |
246 | supported) the callback should be invoked. C<cb> is the callback to invoke |
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180 | |
248 | |
181 | Although the callback might get passed parameters, their value and |
249 | Although the callback might get passed parameters, their value and |
182 | presence is undefined and you cannot rely on them. Portable AnyEvent |
250 | presence is undefined and you cannot rely on them. Portable AnyEvent |
183 | callbacks cannot use arguments passed to time watcher callbacks. |
251 | callbacks cannot use arguments passed to time watcher callbacks. |
184 | |
252 | |
185 | The timer callback will be invoked at most once: if you want a repeating |
253 | The callback will normally be invoked only once. If you specify another |
186 | timer you have to create a new watcher (this is a limitation by both Tk |
254 | parameter, C<interval>, as a strictly positive number (> 0), then the |
187 | and Glib). |
255 | callback will be invoked regularly at that interval (in fractional |
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256 | seconds) after the first invocation. If C<interval> is specified with a |
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257 | false value, then it is treated as if it were not specified at all. |
188 | |
258 | |
189 | Example: |
259 | The callback will be rescheduled before invoking the callback, but no |
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260 | attempt is made to avoid timer drift in most backends, so the interval is |
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261 | only approximate. |
190 | |
262 | |
191 | # fire an event after 7.7 seconds |
263 | Example: fire an event after 7.7 seconds. |
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264 | |
192 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
265 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
193 | warn "timeout\n"; |
266 | warn "timeout\n"; |
194 | }); |
267 | }); |
195 | |
268 | |
196 | # to cancel the timer: |
269 | # to cancel the timer: |
197 | undef $w; |
270 | undef $w; |
198 | |
271 | |
199 | Example 2: |
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200 | |
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201 | # fire an event after 0.5 seconds, then roughly every second |
272 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
202 | my $w; |
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203 | |
273 | |
204 | my $cb = sub { |
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205 | # cancel the old timer while creating a new one |
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206 | $w = AnyEvent->timer (after => 1, cb => $cb); |
274 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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275 | warn "timeout\n"; |
207 | }; |
276 | }; |
208 | |
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209 | # start the "loop" by creating the first watcher |
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210 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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211 | |
277 | |
212 | =head3 TIMING ISSUES |
278 | =head3 TIMING ISSUES |
213 | |
279 | |
214 | There are two ways to handle timers: based on real time (relative, "fire |
280 | There are two ways to handle timers: based on real time (relative, "fire |
215 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
281 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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217 | |
283 | |
218 | While most event loops expect timers to specified in a relative way, they |
284 | While most event loops expect timers to specified in a relative way, they |
219 | use absolute time internally. This makes a difference when your clock |
285 | use absolute time internally. This makes a difference when your clock |
220 | "jumps", for example, when ntp decides to set your clock backwards from |
286 | "jumps", for example, when ntp decides to set your clock backwards from |
221 | the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to |
287 | the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to |
222 | fire "after" a second might actually take six years to finally fire. |
288 | fire "after a second" might actually take six years to finally fire. |
223 | |
289 | |
224 | AnyEvent cannot compensate for this. The only event loop that is conscious |
290 | AnyEvent cannot compensate for this. The only event loop that is conscious |
225 | about these issues is L<EV>, which offers both relative (ev_timer, based |
291 | of these issues is L<EV>, which offers both relative (ev_timer, based |
226 | on true relative time) and absolute (ev_periodic, based on wallclock time) |
292 | on true relative time) and absolute (ev_periodic, based on wallclock time) |
227 | timers. |
293 | timers. |
228 | |
294 | |
229 | AnyEvent always prefers relative timers, if available, matching the |
295 | AnyEvent always prefers relative timers, if available, matching the |
230 | AnyEvent API. |
296 | AnyEvent API. |
231 | |
297 | |
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298 | AnyEvent has two additional methods that return the "current time": |
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299 | |
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300 | =over 4 |
|
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301 | |
|
|
302 | =item AnyEvent->time |
|
|
303 | |
|
|
304 | This returns the "current wallclock time" as a fractional number of |
|
|
305 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
|
|
306 | return, and the result is guaranteed to be compatible with those). |
|
|
307 | |
|
|
308 | It progresses independently of any event loop processing, i.e. each call |
|
|
309 | will check the system clock, which usually gets updated frequently. |
|
|
310 | |
|
|
311 | =item AnyEvent->now |
|
|
312 | |
|
|
313 | This also returns the "current wallclock time", but unlike C<time>, above, |
|
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314 | this value might change only once per event loop iteration, depending on |
|
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315 | the event loop (most return the same time as C<time>, above). This is the |
|
|
316 | time that AnyEvent's timers get scheduled against. |
|
|
317 | |
|
|
318 | I<In almost all cases (in all cases if you don't care), this is the |
|
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319 | function to call when you want to know the current time.> |
|
|
320 | |
|
|
321 | This function is also often faster then C<< AnyEvent->time >>, and |
|
|
322 | thus the preferred method if you want some timestamp (for example, |
|
|
323 | L<AnyEvent::Handle> uses this to update its activity timeouts). |
|
|
324 | |
|
|
325 | The rest of this section is only of relevance if you try to be very exact |
|
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326 | with your timing; you can skip it without a bad conscience. |
|
|
327 | |
|
|
328 | For a practical example of when these times differ, consider L<Event::Lib> |
|
|
329 | and L<EV> and the following set-up: |
|
|
330 | |
|
|
331 | The event loop is running and has just invoked one of your callbacks at |
|
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332 | time=500 (assume no other callbacks delay processing). In your callback, |
|
|
333 | you wait a second by executing C<sleep 1> (blocking the process for a |
|
|
334 | second) and then (at time=501) you create a relative timer that fires |
|
|
335 | after three seconds. |
|
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336 | |
|
|
337 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
|
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338 | both return C<501>, because that is the current time, and the timer will |
|
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339 | be scheduled to fire at time=504 (C<501> + C<3>). |
|
|
340 | |
|
|
341 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
|
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342 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
|
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343 | last event processing phase started. With L<EV>, your timer gets scheduled |
|
|
344 | to run at time=503 (C<500> + C<3>). |
|
|
345 | |
|
|
346 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
|
|
347 | regardless of any delays introduced by event processing. However, most |
|
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348 | callbacks do not expect large delays in processing, so this causes a |
|
|
349 | higher drift (and a lot more system calls to get the current time). |
|
|
350 | |
|
|
351 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
|
|
352 | the same time, regardless of how long event processing actually took. |
|
|
353 | |
|
|
354 | In either case, if you care (and in most cases, you don't), then you |
|
|
355 | can get whatever behaviour you want with any event loop, by taking the |
|
|
356 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
|
|
357 | account. |
|
|
358 | |
|
|
359 | =item AnyEvent->now_update |
|
|
360 | |
|
|
361 | Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache |
|
|
362 | the current time for each loop iteration (see the discussion of L<< |
|
|
363 | AnyEvent->now >>, above). |
|
|
364 | |
|
|
365 | When a callback runs for a long time (or when the process sleeps), then |
|
|
366 | this "current" time will differ substantially from the real time, which |
|
|
367 | might affect timers and time-outs. |
|
|
368 | |
|
|
369 | When this is the case, you can call this method, which will update the |
|
|
370 | event loop's idea of "current time". |
|
|
371 | |
|
|
372 | A typical example would be a script in a web server (e.g. C<mod_perl>) - |
|
|
373 | when mod_perl executes the script, then the event loop will have the wrong |
|
|
374 | idea about the "current time" (being potentially far in the past, when the |
|
|
375 | script ran the last time). In that case you should arrange a call to C<< |
|
|
376 | AnyEvent->now_update >> each time the web server process wakes up again |
|
|
377 | (e.g. at the start of your script, or in a handler). |
|
|
378 | |
|
|
379 | Note that updating the time I<might> cause some events to be handled. |
|
|
380 | |
|
|
381 | =back |
|
|
382 | |
232 | =head2 SIGNAL WATCHERS |
383 | =head2 SIGNAL WATCHERS |
233 | |
384 | |
|
|
385 | $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>); |
|
|
386 | |
234 | You can watch for signals using a signal watcher, C<signal> is the signal |
387 | You can watch for signals using a signal watcher, C<signal> is the signal |
235 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
388 | I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl |
236 | be invoked whenever a signal occurs. |
389 | callback to be invoked whenever a signal occurs. |
237 | |
390 | |
238 | Although the callback might get passed parameters, their value and |
391 | Although the callback might get passed parameters, their value and |
239 | presence is undefined and you cannot rely on them. Portable AnyEvent |
392 | presence is undefined and you cannot rely on them. Portable AnyEvent |
240 | callbacks cannot use arguments passed to signal watcher callbacks. |
393 | callbacks cannot use arguments passed to signal watcher callbacks. |
241 | |
394 | |
242 | Multiple signal occurances can be clumped together into one callback |
395 | Multiple signal occurrences can be clumped together into one callback |
243 | invocation, and callback invocation will be synchronous. synchronous means |
396 | invocation, and callback invocation will be synchronous. Synchronous means |
244 | that it might take a while until the signal gets handled by the process, |
397 | that it might take a while until the signal gets handled by the process, |
245 | but it is guarenteed not to interrupt any other callbacks. |
398 | but it is guaranteed not to interrupt any other callbacks. |
246 | |
399 | |
247 | The main advantage of using these watchers is that you can share a signal |
400 | The main advantage of using these watchers is that you can share a signal |
248 | between multiple watchers. |
401 | between multiple watchers, and AnyEvent will ensure that signals will not |
|
|
402 | interrupt your program at bad times. |
249 | |
403 | |
250 | This watcher might use C<%SIG>, so programs overwriting those signals |
404 | This watcher might use C<%SIG> (depending on the event loop used), |
251 | directly will likely not work correctly. |
405 | so programs overwriting those signals directly will likely not work |
|
|
406 | correctly. |
252 | |
407 | |
253 | Example: exit on SIGINT |
408 | Example: exit on SIGINT |
254 | |
409 | |
255 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
410 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
256 | |
411 | |
|
|
412 | =head3 Restart Behaviour |
|
|
413 | |
|
|
414 | While restart behaviour is up to the event loop implementation, most will |
|
|
415 | not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's |
|
|
416 | pure perl implementation). |
|
|
417 | |
|
|
418 | =head3 Safe/Unsafe Signals |
|
|
419 | |
|
|
420 | Perl signals can be either "safe" (synchronous to opcode handling) or |
|
|
421 | "unsafe" (asynchronous) - the former might get delayed indefinitely, the |
|
|
422 | latter might corrupt your memory. |
|
|
423 | |
|
|
424 | AnyEvent signal handlers are, in addition, synchronous to the event loop, |
|
|
425 | i.e. they will not interrupt your running perl program but will only be |
|
|
426 | called as part of the normal event handling (just like timer, I/O etc. |
|
|
427 | callbacks, too). |
|
|
428 | |
|
|
429 | =head3 Signal Races, Delays and Workarounds |
|
|
430 | |
|
|
431 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
|
|
432 | callbacks to signals in a generic way, which is a pity, as you cannot |
|
|
433 | do race-free signal handling in perl, requiring C libraries for |
|
|
434 | this. AnyEvent will try to do its best, which means in some cases, |
|
|
435 | signals will be delayed. The maximum time a signal might be delayed is |
|
|
436 | specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This |
|
|
437 | variable can be changed only before the first signal watcher is created, |
|
|
438 | and should be left alone otherwise. This variable determines how often |
|
|
439 | AnyEvent polls for signals (in case a wake-up was missed). Higher values |
|
|
440 | will cause fewer spurious wake-ups, which is better for power and CPU |
|
|
441 | saving. |
|
|
442 | |
|
|
443 | All these problems can be avoided by installing the optional |
|
|
444 | L<Async::Interrupt> module, which works with most event loops. It will not |
|
|
445 | work with inherently broken event loops such as L<Event> or L<Event::Lib> |
|
|
446 | (and not with L<POE> currently, as POE does its own workaround with |
|
|
447 | one-second latency). For those, you just have to suffer the delays. |
|
|
448 | |
257 | =head2 CHILD PROCESS WATCHERS |
449 | =head2 CHILD PROCESS WATCHERS |
258 | |
450 | |
|
|
451 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
|
|
452 | |
259 | You can also watch on a child process exit and catch its exit status. |
453 | You can also watch for a child process exit and catch its exit status. |
260 | |
454 | |
261 | The child process is specified by the C<pid> argument (if set to C<0>, it |
455 | The child process is specified by the C<pid> argument (on some backends, |
262 | watches for any child process exit). The watcher will trigger as often |
456 | using C<0> watches for any child process exit, on others this will |
263 | as status change for the child are received. This works by installing a |
457 | croak). The watcher will be triggered only when the child process has |
264 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
458 | finished and an exit status is available, not on any trace events |
265 | and exit status (as returned by waitpid), so unlike other watcher types, |
459 | (stopped/continued). |
266 | you I<can> rely on child watcher callback arguments. |
460 | |
|
|
461 | The callback will be called with the pid and exit status (as returned by |
|
|
462 | waitpid), so unlike other watcher types, you I<can> rely on child watcher |
|
|
463 | callback arguments. |
|
|
464 | |
|
|
465 | This watcher type works by installing a signal handler for C<SIGCHLD>, |
|
|
466 | and since it cannot be shared, nothing else should use SIGCHLD or reap |
|
|
467 | random child processes (waiting for specific child processes, e.g. inside |
|
|
468 | C<system>, is just fine). |
267 | |
469 | |
268 | There is a slight catch to child watchers, however: you usually start them |
470 | There is a slight catch to child watchers, however: you usually start them |
269 | I<after> the child process was created, and this means the process could |
471 | I<after> the child process was created, and this means the process could |
270 | have exited already (and no SIGCHLD will be sent anymore). |
472 | have exited already (and no SIGCHLD will be sent anymore). |
271 | |
473 | |
272 | Not all event models handle this correctly (POE doesn't), but even for |
474 | Not all event models handle this correctly (neither POE nor IO::Async do, |
|
|
475 | see their AnyEvent::Impl manpages for details), but even for event models |
273 | event models that I<do> handle this correctly, they usually need to be |
476 | that I<do> handle this correctly, they usually need to be loaded before |
274 | loaded before the process exits (i.e. before you fork in the first place). |
477 | the process exits (i.e. before you fork in the first place). AnyEvent's |
|
|
478 | pure perl event loop handles all cases correctly regardless of when you |
|
|
479 | start the watcher. |
275 | |
480 | |
276 | This means you cannot create a child watcher as the very first thing in an |
481 | This means you cannot create a child watcher as the very first |
277 | AnyEvent program, you I<have> to create at least one watcher before you |
482 | thing in an AnyEvent program, you I<have> to create at least one |
278 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
483 | watcher before you C<fork> the child (alternatively, you can call |
|
|
484 | C<AnyEvent::detect>). |
|
|
485 | |
|
|
486 | As most event loops do not support waiting for child events, they will be |
|
|
487 | emulated by AnyEvent in most cases, in which the latency and race problems |
|
|
488 | mentioned in the description of signal watchers apply. |
279 | |
489 | |
280 | Example: fork a process and wait for it |
490 | Example: fork a process and wait for it |
281 | |
491 | |
282 | my $done = AnyEvent->condvar; |
492 | my $done = AnyEvent->condvar; |
283 | |
493 | |
284 | my $pid = fork or exit 5; |
494 | my $pid = fork or exit 5; |
285 | |
495 | |
286 | my $w = AnyEvent->child ( |
496 | my $w = AnyEvent->child ( |
287 | pid => $pid, |
497 | pid => $pid, |
288 | cb => sub { |
498 | cb => sub { |
289 | my ($pid, $status) = @_; |
499 | my ($pid, $status) = @_; |
290 | warn "pid $pid exited with status $status"; |
500 | warn "pid $pid exited with status $status"; |
291 | $done->send; |
501 | $done->send; |
292 | }, |
502 | }, |
293 | ); |
503 | ); |
294 | |
504 | |
295 | # do something else, then wait for process exit |
505 | # do something else, then wait for process exit |
296 | $done->recv; |
506 | $done->recv; |
|
|
507 | |
|
|
508 | =head2 IDLE WATCHERS |
|
|
509 | |
|
|
510 | $w = AnyEvent->idle (cb => <callback>); |
|
|
511 | |
|
|
512 | This will repeatedly invoke the callback after the process becomes idle, |
|
|
513 | until either the watcher is destroyed or new events have been detected. |
|
|
514 | |
|
|
515 | Idle watchers are useful when there is a need to do something, but it |
|
|
516 | is not so important (or wise) to do it instantly. The callback will be |
|
|
517 | invoked only when there is "nothing better to do", which is usually |
|
|
518 | defined as "all outstanding events have been handled and no new events |
|
|
519 | have been detected". That means that idle watchers ideally get invoked |
|
|
520 | when the event loop has just polled for new events but none have been |
|
|
521 | detected. Instead of blocking to wait for more events, the idle watchers |
|
|
522 | will be invoked. |
|
|
523 | |
|
|
524 | Unfortunately, most event loops do not really support idle watchers (only |
|
|
525 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
|
|
526 | will simply call the callback "from time to time". |
|
|
527 | |
|
|
528 | Example: read lines from STDIN, but only process them when the |
|
|
529 | program is otherwise idle: |
|
|
530 | |
|
|
531 | my @lines; # read data |
|
|
532 | my $idle_w; |
|
|
533 | my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
|
|
534 | push @lines, scalar <STDIN>; |
|
|
535 | |
|
|
536 | # start an idle watcher, if not already done |
|
|
537 | $idle_w ||= AnyEvent->idle (cb => sub { |
|
|
538 | # handle only one line, when there are lines left |
|
|
539 | if (my $line = shift @lines) { |
|
|
540 | print "handled when idle: $line"; |
|
|
541 | } else { |
|
|
542 | # otherwise disable the idle watcher again |
|
|
543 | undef $idle_w; |
|
|
544 | } |
|
|
545 | }); |
|
|
546 | }); |
297 | |
547 | |
298 | =head2 CONDITION VARIABLES |
548 | =head2 CONDITION VARIABLES |
|
|
549 | |
|
|
550 | $cv = AnyEvent->condvar; |
|
|
551 | |
|
|
552 | $cv->send (<list>); |
|
|
553 | my @res = $cv->recv; |
299 | |
554 | |
300 | If you are familiar with some event loops you will know that all of them |
555 | If you are familiar with some event loops you will know that all of them |
301 | require you to run some blocking "loop", "run" or similar function that |
556 | require you to run some blocking "loop", "run" or similar function that |
302 | will actively watch for new events and call your callbacks. |
557 | will actively watch for new events and call your callbacks. |
303 | |
558 | |
304 | AnyEvent is different, it expects somebody else to run the event loop and |
559 | AnyEvent is slightly different: it expects somebody else to run the event |
305 | will only block when necessary (usually when told by the user). |
560 | loop and will only block when necessary (usually when told by the user). |
306 | |
561 | |
307 | The instrument to do that is called a "condition variable", so called |
562 | The tool to do that is called a "condition variable", so called because |
308 | because they represent a condition that must become true. |
563 | they represent a condition that must become true. |
|
|
564 | |
|
|
565 | Now is probably a good time to look at the examples further below. |
309 | |
566 | |
310 | Condition variables can be created by calling the C<< AnyEvent->condvar |
567 | Condition variables can be created by calling the C<< AnyEvent->condvar |
311 | >> method, usually without arguments. The only argument pair allowed is |
568 | >> method, usually without arguments. The only argument pair allowed is |
312 | C<cb>, which specifies a callback to be called when the condition variable |
569 | C<cb>, which specifies a callback to be called when the condition variable |
313 | becomes true. |
570 | becomes true, with the condition variable as the first argument (but not |
|
|
571 | the results). |
314 | |
572 | |
315 | After creation, the conditon variable is "false" until it becomes "true" |
573 | After creation, the condition variable is "false" until it becomes "true" |
316 | by calling the C<send> method. |
574 | by calling the C<send> method (or calling the condition variable as if it |
|
|
575 | were a callback, read about the caveats in the description for the C<< |
|
|
576 | ->send >> method). |
317 | |
577 | |
318 | Condition variables are similar to callbacks, except that you can |
578 | Since condition variables are the most complex part of the AnyEvent API, here are |
319 | optionally wait for them. They can also be called merge points - points |
579 | some different mental models of what they are - pick the ones you can connect to: |
320 | in time where multiple outstandign events have been processed. And yet |
580 | |
321 | another way to call them is transations - each condition variable can be |
581 | =over 4 |
322 | used to represent a transaction, which finishes at some point and delivers |
582 | |
323 | a result. |
583 | =item * Condition variables are like callbacks - you can call them (and pass them instead |
|
|
584 | of callbacks). Unlike callbacks however, you can also wait for them to be called. |
|
|
585 | |
|
|
586 | =item * Condition variables are signals - one side can emit or send them, |
|
|
587 | the other side can wait for them, or install a handler that is called when |
|
|
588 | the signal fires. |
|
|
589 | |
|
|
590 | =item * Condition variables are like "Merge Points" - points in your program |
|
|
591 | where you merge multiple independent results/control flows into one. |
|
|
592 | |
|
|
593 | =item * Condition variables represent a transaction - functions that start |
|
|
594 | some kind of transaction can return them, leaving the caller the choice |
|
|
595 | between waiting in a blocking fashion, or setting a callback. |
|
|
596 | |
|
|
597 | =item * Condition variables represent future values, or promises to deliver |
|
|
598 | some result, long before the result is available. |
|
|
599 | |
|
|
600 | =back |
324 | |
601 | |
325 | Condition variables are very useful to signal that something has finished, |
602 | Condition variables are very useful to signal that something has finished, |
326 | for example, if you write a module that does asynchronous http requests, |
603 | for example, if you write a module that does asynchronous http requests, |
327 | then a condition variable would be the ideal candidate to signal the |
604 | then a condition variable would be the ideal candidate to signal the |
328 | availability of results. The user can either act when the callback is |
605 | availability of results. The user can either act when the callback is |
… | |
… | |
332 | you can block your main program until an event occurs - for example, you |
609 | you can block your main program until an event occurs - for example, you |
333 | could C<< ->recv >> in your main program until the user clicks the Quit |
610 | could C<< ->recv >> in your main program until the user clicks the Quit |
334 | button of your app, which would C<< ->send >> the "quit" event. |
611 | button of your app, which would C<< ->send >> the "quit" event. |
335 | |
612 | |
336 | Note that condition variables recurse into the event loop - if you have |
613 | Note that condition variables recurse into the event loop - if you have |
337 | two pieces of code that call C<< ->recv >> in a round-robbin fashion, you |
614 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
338 | lose. Therefore, condition variables are good to export to your caller, but |
615 | lose. Therefore, condition variables are good to export to your caller, but |
339 | you should avoid making a blocking wait yourself, at least in callbacks, |
616 | you should avoid making a blocking wait yourself, at least in callbacks, |
340 | as this asks for trouble. |
617 | as this asks for trouble. |
341 | |
618 | |
342 | Condition variables are represented by hash refs in perl, and the keys |
619 | Condition variables are represented by hash refs in perl, and the keys |
343 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
620 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
344 | easy (it is often useful to build your own transaction class on top of |
621 | easy (it is often useful to build your own transaction class on top of |
345 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
622 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
346 | it's C<new> method in your own C<new> method. |
623 | its C<new> method in your own C<new> method. |
347 | |
624 | |
348 | There are two "sides" to a condition variable - the "producer side" which |
625 | There are two "sides" to a condition variable - the "producer side" which |
349 | eventually calls C<< -> send >>, and the "consumer side", which waits |
626 | eventually calls C<< -> send >>, and the "consumer side", which waits |
350 | for the send to occur. |
627 | for the send to occur. |
351 | |
628 | |
352 | Example: |
629 | Example: wait for a timer. |
353 | |
630 | |
354 | # wait till the result is ready |
631 | # condition: "wait till the timer is fired" |
355 | my $result_ready = AnyEvent->condvar; |
632 | my $timer_fired = AnyEvent->condvar; |
356 | |
633 | |
357 | # do something such as adding a timer |
634 | # create the timer - we could wait for, say |
358 | # or socket watcher the calls $result_ready->send |
635 | # a handle becomign ready, or even an |
359 | # when the "result" is ready. |
636 | # AnyEvent::HTTP request to finish, but |
360 | # in this case, we simply use a timer: |
637 | # in this case, we simply use a timer: |
361 | my $w = AnyEvent->timer ( |
638 | my $w = AnyEvent->timer ( |
362 | after => 1, |
639 | after => 1, |
363 | cb => sub { $result_ready->send }, |
640 | cb => sub { $timer_fired->send }, |
364 | ); |
641 | ); |
365 | |
642 | |
366 | # this "blocks" (while handling events) till the callback |
643 | # this "blocks" (while handling events) till the callback |
367 | # calls send |
644 | # calls ->send |
368 | $result_ready->recv; |
645 | $timer_fired->recv; |
|
|
646 | |
|
|
647 | Example: wait for a timer, but take advantage of the fact that condition |
|
|
648 | variables are also callable directly. |
|
|
649 | |
|
|
650 | my $done = AnyEvent->condvar; |
|
|
651 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
|
652 | $done->recv; |
|
|
653 | |
|
|
654 | Example: Imagine an API that returns a condvar and doesn't support |
|
|
655 | callbacks. This is how you make a synchronous call, for example from |
|
|
656 | the main program: |
|
|
657 | |
|
|
658 | use AnyEvent::CouchDB; |
|
|
659 | |
|
|
660 | ... |
|
|
661 | |
|
|
662 | my @info = $couchdb->info->recv; |
|
|
663 | |
|
|
664 | And this is how you would just set a callback to be called whenever the |
|
|
665 | results are available: |
|
|
666 | |
|
|
667 | $couchdb->info->cb (sub { |
|
|
668 | my @info = $_[0]->recv; |
|
|
669 | }); |
369 | |
670 | |
370 | =head3 METHODS FOR PRODUCERS |
671 | =head3 METHODS FOR PRODUCERS |
371 | |
672 | |
372 | These methods should only be used by the producing side, i.e. the |
673 | These methods should only be used by the producing side, i.e. the |
373 | code/module that eventually sends the signal. Note that it is also |
674 | code/module that eventually sends the signal. Note that it is also |
… | |
… | |
386 | immediately from within send. |
687 | immediately from within send. |
387 | |
688 | |
388 | Any arguments passed to the C<send> call will be returned by all |
689 | Any arguments passed to the C<send> call will be returned by all |
389 | future C<< ->recv >> calls. |
690 | future C<< ->recv >> calls. |
390 | |
691 | |
|
|
692 | Condition variables are overloaded so one can call them directly (as if |
|
|
693 | they were a code reference). Calling them directly is the same as calling |
|
|
694 | C<send>. |
|
|
695 | |
391 | =item $cv->croak ($error) |
696 | =item $cv->croak ($error) |
392 | |
697 | |
393 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
698 | Similar to send, but causes all calls to C<< ->recv >> to invoke |
394 | C<Carp::croak> with the given error message/object/scalar. |
699 | C<Carp::croak> with the given error message/object/scalar. |
395 | |
700 | |
396 | This can be used to signal any errors to the condition variable |
701 | This can be used to signal any errors to the condition variable |
397 | user/consumer. |
702 | user/consumer. Doing it this way instead of calling C<croak> directly |
|
|
703 | delays the error detection, but has the overwhelming advantage that it |
|
|
704 | diagnoses the error at the place where the result is expected, and not |
|
|
705 | deep in some event callback with no connection to the actual code causing |
|
|
706 | the problem. |
398 | |
707 | |
399 | =item $cv->begin ([group callback]) |
708 | =item $cv->begin ([group callback]) |
400 | |
709 | |
401 | =item $cv->end |
710 | =item $cv->end |
402 | |
|
|
403 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
|
|
404 | |
711 | |
405 | These two methods can be used to combine many transactions/events into |
712 | These two methods can be used to combine many transactions/events into |
406 | one. For example, a function that pings many hosts in parallel might want |
713 | one. For example, a function that pings many hosts in parallel might want |
407 | to use a condition variable for the whole process. |
714 | to use a condition variable for the whole process. |
408 | |
715 | |
409 | Every call to C<< ->begin >> will increment a counter, and every call to |
716 | Every call to C<< ->begin >> will increment a counter, and every call to |
410 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
717 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
411 | >>, the (last) callback passed to C<begin> will be executed. That callback |
718 | >>, the (last) callback passed to C<begin> will be executed, passing the |
412 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
719 | condvar as first argument. That callback is I<supposed> to call C<< ->send |
413 | callback was set, C<send> will be called without any arguments. |
720 | >>, but that is not required. If no group callback was set, C<send> will |
|
|
721 | be called without any arguments. |
414 | |
722 | |
415 | Let's clarify this with the ping example: |
723 | You can think of C<< $cv->send >> giving you an OR condition (one call |
|
|
724 | sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND |
|
|
725 | condition (all C<begin> calls must be C<end>'ed before the condvar sends). |
|
|
726 | |
|
|
727 | Let's start with a simple example: you have two I/O watchers (for example, |
|
|
728 | STDOUT and STDERR for a program), and you want to wait for both streams to |
|
|
729 | close before activating a condvar: |
416 | |
730 | |
417 | my $cv = AnyEvent->condvar; |
731 | my $cv = AnyEvent->condvar; |
418 | |
732 | |
|
|
733 | $cv->begin; # first watcher |
|
|
734 | my $w1 = AnyEvent->io (fh => $fh1, cb => sub { |
|
|
735 | defined sysread $fh1, my $buf, 4096 |
|
|
736 | or $cv->end; |
|
|
737 | }); |
|
|
738 | |
|
|
739 | $cv->begin; # second watcher |
|
|
740 | my $w2 = AnyEvent->io (fh => $fh2, cb => sub { |
|
|
741 | defined sysread $fh2, my $buf, 4096 |
|
|
742 | or $cv->end; |
|
|
743 | }); |
|
|
744 | |
|
|
745 | $cv->recv; |
|
|
746 | |
|
|
747 | This works because for every event source (EOF on file handle), there is |
|
|
748 | one call to C<begin>, so the condvar waits for all calls to C<end> before |
|
|
749 | sending. |
|
|
750 | |
|
|
751 | The ping example mentioned above is slightly more complicated, as the |
|
|
752 | there are results to be passwd back, and the number of tasks that are |
|
|
753 | begun can potentially be zero: |
|
|
754 | |
|
|
755 | my $cv = AnyEvent->condvar; |
|
|
756 | |
419 | my %result; |
757 | my %result; |
420 | $cv->begin (sub { $cv->send (\%result) }); |
758 | $cv->begin (sub { shift->send (\%result) }); |
421 | |
759 | |
422 | for my $host (@list_of_hosts) { |
760 | for my $host (@list_of_hosts) { |
423 | $cv->begin; |
761 | $cv->begin; |
424 | ping_host_then_call_callback $host, sub { |
762 | ping_host_then_call_callback $host, sub { |
425 | $result{$host} = ...; |
763 | $result{$host} = ...; |
… | |
… | |
440 | loop, which serves two important purposes: first, it sets the callback |
778 | loop, which serves two important purposes: first, it sets the callback |
441 | to be called once the counter reaches C<0>, and second, it ensures that |
779 | to be called once the counter reaches C<0>, and second, it ensures that |
442 | C<send> is called even when C<no> hosts are being pinged (the loop |
780 | C<send> is called even when C<no> hosts are being pinged (the loop |
443 | doesn't execute once). |
781 | doesn't execute once). |
444 | |
782 | |
445 | This is the general pattern when you "fan out" into multiple subrequests: |
783 | This is the general pattern when you "fan out" into multiple (but |
446 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
784 | potentially zero) subrequests: use an outer C<begin>/C<end> pair to set |
447 | is called at least once, and then, for each subrequest you start, call |
785 | the callback and ensure C<end> is called at least once, and then, for each |
448 | C<begin> and for eahc subrequest you finish, call C<end>. |
786 | subrequest you start, call C<begin> and for each subrequest you finish, |
|
|
787 | call C<end>. |
449 | |
788 | |
450 | =back |
789 | =back |
451 | |
790 | |
452 | =head3 METHODS FOR CONSUMERS |
791 | =head3 METHODS FOR CONSUMERS |
453 | |
792 | |
… | |
… | |
457 | =over 4 |
796 | =over 4 |
458 | |
797 | |
459 | =item $cv->recv |
798 | =item $cv->recv |
460 | |
799 | |
461 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
800 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
462 | >> methods have been called on c<$cv>, while servicing other watchers |
801 | >> methods have been called on C<$cv>, while servicing other watchers |
463 | normally. |
802 | normally. |
464 | |
803 | |
465 | You can only wait once on a condition - additional calls are valid but |
804 | You can only wait once on a condition - additional calls are valid but |
466 | will return immediately. |
805 | will return immediately. |
467 | |
806 | |
… | |
… | |
469 | function will call C<croak>. |
808 | function will call C<croak>. |
470 | |
809 | |
471 | In list context, all parameters passed to C<send> will be returned, |
810 | In list context, all parameters passed to C<send> will be returned, |
472 | in scalar context only the first one will be returned. |
811 | in scalar context only the first one will be returned. |
473 | |
812 | |
|
|
813 | Note that doing a blocking wait in a callback is not supported by any |
|
|
814 | event loop, that is, recursive invocation of a blocking C<< ->recv |
|
|
815 | >> is not allowed, and the C<recv> call will C<croak> if such a |
|
|
816 | condition is detected. This condition can be slightly loosened by using |
|
|
817 | L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from |
|
|
818 | any thread that doesn't run the event loop itself. |
|
|
819 | |
474 | Not all event models support a blocking wait - some die in that case |
820 | Not all event models support a blocking wait - some die in that case |
475 | (programs might want to do that to stay interactive), so I<if you are |
821 | (programs might want to do that to stay interactive), so I<if you are |
476 | using this from a module, never require a blocking wait>, but let the |
822 | using this from a module, never require a blocking wait>. Instead, let the |
477 | caller decide whether the call will block or not (for example, by coupling |
823 | caller decide whether the call will block or not (for example, by coupling |
478 | condition variables with some kind of request results and supporting |
824 | condition variables with some kind of request results and supporting |
479 | callbacks so the caller knows that getting the result will not block, |
825 | callbacks so the caller knows that getting the result will not block, |
480 | while still suppporting blocking waits if the caller so desires). |
826 | while still supporting blocking waits if the caller so desires). |
481 | |
827 | |
482 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
|
|
483 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
|
|
484 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
|
|
485 | can supply. |
|
|
486 | |
|
|
487 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
488 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
489 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
490 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
491 | coroutine (one that doesn't run the event loop). |
|
|
492 | |
|
|
493 | You can ensure that C<< -recv >> never blocks by setting a callback and |
828 | You can ensure that C<< ->recv >> never blocks by setting a callback and |
494 | only calling C<< ->recv >> from within that callback (or at a later |
829 | only calling C<< ->recv >> from within that callback (or at a later |
495 | time). This will work even when the event loop does not support blocking |
830 | time). This will work even when the event loop does not support blocking |
496 | waits otherwise. |
831 | waits otherwise. |
497 | |
832 | |
498 | =item $bool = $cv->ready |
833 | =item $bool = $cv->ready |
499 | |
834 | |
500 | Returns true when the condition is "true", i.e. whether C<send> or |
835 | Returns true when the condition is "true", i.e. whether C<send> or |
501 | C<croak> have been called. |
836 | C<croak> have been called. |
502 | |
837 | |
503 | =item $cb = $cv->cb ([new callback]) |
838 | =item $cb = $cv->cb ($cb->($cv)) |
504 | |
839 | |
505 | This is a mutator function that returns the callback set and optionally |
840 | This is a mutator function that returns the callback set and optionally |
506 | replaces it before doing so. |
841 | replaces it before doing so. |
507 | |
842 | |
508 | The callback will be called when the condition becomes "true", i.e. when |
843 | The callback will be called when the condition becomes "true", i.e. when |
509 | C<send> or C<croak> are called. Calling C<recv> inside the callback |
844 | C<send> or C<croak> are called, with the only argument being the |
|
|
845 | condition variable itself. If the condition is already true, the |
|
|
846 | callback is called immediately when it is set. Calling C<recv> inside |
510 | or at any later time is guaranteed not to block. |
847 | the callback or at any later time is guaranteed not to block. |
511 | |
848 | |
512 | =back |
849 | =back |
513 | |
850 | |
|
|
851 | =head1 SUPPORTED EVENT LOOPS/BACKENDS |
|
|
852 | |
|
|
853 | The available backend classes are (every class has its own manpage): |
|
|
854 | |
|
|
855 | =over 4 |
|
|
856 | |
|
|
857 | =item Backends that are autoprobed when no other event loop can be found. |
|
|
858 | |
|
|
859 | EV is the preferred backend when no other event loop seems to be in |
|
|
860 | use. If EV is not installed, then AnyEvent will fall back to its own |
|
|
861 | pure-perl implementation, which is available everywhere as it comes with |
|
|
862 | AnyEvent itself. |
|
|
863 | |
|
|
864 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
|
|
865 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
|
|
866 | |
|
|
867 | =item Backends that are transparently being picked up when they are used. |
|
|
868 | |
|
|
869 | These will be used if they are already loaded when the first watcher |
|
|
870 | is created, in which case it is assumed that the application is using |
|
|
871 | them. This means that AnyEvent will automatically pick the right backend |
|
|
872 | when the main program loads an event module before anything starts to |
|
|
873 | create watchers. Nothing special needs to be done by the main program. |
|
|
874 | |
|
|
875 | AnyEvent::Impl::Event based on Event, very stable, few glitches. |
|
|
876 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
|
|
877 | AnyEvent::Impl::Tk based on Tk, very broken. |
|
|
878 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
|
|
879 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
|
|
880 | AnyEvent::Impl::Irssi used when running within irssi. |
|
|
881 | |
|
|
882 | =item Backends with special needs. |
|
|
883 | |
|
|
884 | Qt requires the Qt::Application to be instantiated first, but will |
|
|
885 | otherwise be picked up automatically. As long as the main program |
|
|
886 | instantiates the application before any AnyEvent watchers are created, |
|
|
887 | everything should just work. |
|
|
888 | |
|
|
889 | AnyEvent::Impl::Qt based on Qt. |
|
|
890 | |
|
|
891 | Support for IO::Async can only be partial, as it is too broken and |
|
|
892 | architecturally limited to even support the AnyEvent API. It also |
|
|
893 | is the only event loop that needs the loop to be set explicitly, so |
|
|
894 | it can only be used by a main program knowing about AnyEvent. See |
|
|
895 | L<AnyEvent::Impl::IOAsync> for the gory details. |
|
|
896 | |
|
|
897 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed. |
|
|
898 | |
|
|
899 | =item Event loops that are indirectly supported via other backends. |
|
|
900 | |
|
|
901 | Some event loops can be supported via other modules: |
|
|
902 | |
|
|
903 | There is no direct support for WxWidgets (L<Wx>) or L<Prima>. |
|
|
904 | |
|
|
905 | B<WxWidgets> has no support for watching file handles. However, you can |
|
|
906 | use WxWidgets through the POE adaptor, as POE has a Wx backend that simply |
|
|
907 | polls 20 times per second, which was considered to be too horrible to even |
|
|
908 | consider for AnyEvent. |
|
|
909 | |
|
|
910 | B<Prima> is not supported as nobody seems to be using it, but it has a POE |
|
|
911 | backend, so it can be supported through POE. |
|
|
912 | |
|
|
913 | AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to |
|
|
914 | load L<POE> when detecting them, in the hope that POE will pick them up, |
|
|
915 | in which case everything will be automatic. |
|
|
916 | |
|
|
917 | =back |
|
|
918 | |
514 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
919 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
515 | |
920 | |
|
|
921 | These are not normally required to use AnyEvent, but can be useful to |
|
|
922 | write AnyEvent extension modules. |
|
|
923 | |
516 | =over 4 |
924 | =over 4 |
517 | |
925 | |
518 | =item $AnyEvent::MODEL |
926 | =item $AnyEvent::MODEL |
519 | |
927 | |
520 | Contains C<undef> until the first watcher is being created. Then it |
928 | Contains C<undef> until the first watcher is being created, before the |
|
|
929 | backend has been autodetected. |
|
|
930 | |
521 | contains the event model that is being used, which is the name of the |
931 | Afterwards it contains the event model that is being used, which is the |
522 | Perl class implementing the model. This class is usually one of the |
932 | name of the Perl class implementing the model. This class is usually one |
523 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
933 | of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the |
524 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
934 | case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it |
525 | |
935 | will be C<urxvt::anyevent>). |
526 | The known classes so far are: |
|
|
527 | |
|
|
528 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
|
|
529 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
530 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
|
|
531 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
|
|
532 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
|
|
533 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
|
|
534 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
|
|
535 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
|
|
536 | |
|
|
537 | There is no support for WxWidgets, as WxWidgets has no support for |
|
|
538 | watching file handles. However, you can use WxWidgets through the |
|
|
539 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
|
|
540 | second, which was considered to be too horrible to even consider for |
|
|
541 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
|
|
542 | it's adaptor. |
|
|
543 | |
|
|
544 | AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when |
|
|
545 | autodetecting them. |
|
|
546 | |
936 | |
547 | =item AnyEvent::detect |
937 | =item AnyEvent::detect |
548 | |
938 | |
549 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
939 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
550 | if necessary. You should only call this function right before you would |
940 | if necessary. You should only call this function right before you would |
551 | have created an AnyEvent watcher anyway, that is, as late as possible at |
941 | have created an AnyEvent watcher anyway, that is, as late as possible at |
552 | runtime. |
942 | runtime, and not e.g. during initialisation of your module. |
|
|
943 | |
|
|
944 | If you need to do some initialisation before AnyEvent watchers are |
|
|
945 | created, use C<post_detect>. |
553 | |
946 | |
554 | =item $guard = AnyEvent::post_detect { BLOCK } |
947 | =item $guard = AnyEvent::post_detect { BLOCK } |
555 | |
948 | |
556 | Arranges for the code block to be executed as soon as the event model is |
949 | Arranges for the code block to be executed as soon as the event model is |
557 | autodetected (or immediately if this has already happened). |
950 | autodetected (or immediately if that has already happened). |
|
|
951 | |
|
|
952 | The block will be executed I<after> the actual backend has been detected |
|
|
953 | (C<$AnyEvent::MODEL> is set), but I<before> any watchers have been |
|
|
954 | created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do |
|
|
955 | other initialisations - see the sources of L<AnyEvent::Strict> or |
|
|
956 | L<AnyEvent::AIO> to see how this is used. |
|
|
957 | |
|
|
958 | The most common usage is to create some global watchers, without forcing |
|
|
959 | event module detection too early, for example, L<AnyEvent::AIO> creates |
|
|
960 | and installs the global L<IO::AIO> watcher in a C<post_detect> block to |
|
|
961 | avoid autodetecting the event module at load time. |
558 | |
962 | |
559 | If called in scalar or list context, then it creates and returns an object |
963 | If called in scalar or list context, then it creates and returns an object |
560 | that automatically removes the callback again when it is destroyed. See |
964 | that automatically removes the callback again when it is destroyed (or |
|
|
965 | C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for |
561 | L<Coro::BDB> for a case where this is useful. |
966 | a case where this is useful. |
|
|
967 | |
|
|
968 | Example: Create a watcher for the IO::AIO module and store it in |
|
|
969 | C<$WATCHER>, but do so only do so after the event loop is initialised. |
|
|
970 | |
|
|
971 | our WATCHER; |
|
|
972 | |
|
|
973 | my $guard = AnyEvent::post_detect { |
|
|
974 | $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); |
|
|
975 | }; |
|
|
976 | |
|
|
977 | # the ||= is important in case post_detect immediately runs the block, |
|
|
978 | # as to not clobber the newly-created watcher. assigning both watcher and |
|
|
979 | # post_detect guard to the same variable has the advantage of users being |
|
|
980 | # able to just C<undef $WATCHER> if the watcher causes them grief. |
|
|
981 | |
|
|
982 | $WATCHER ||= $guard; |
562 | |
983 | |
563 | =item @AnyEvent::post_detect |
984 | =item @AnyEvent::post_detect |
564 | |
985 | |
565 | If there are any code references in this array (you can C<push> to it |
986 | If there are any code references in this array (you can C<push> to it |
566 | before or after loading AnyEvent), then they will called directly after |
987 | before or after loading AnyEvent), then they will be called directly |
567 | the event loop has been chosen. |
988 | after the event loop has been chosen. |
568 | |
989 | |
569 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
990 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
570 | if it contains a true value then the event loop has already been detected, |
991 | if it is defined then the event loop has already been detected, and the |
571 | and the array will be ignored. |
992 | array will be ignored. |
572 | |
993 | |
573 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
994 | Best use C<AnyEvent::post_detect { BLOCK }> when your application allows |
|
|
995 | it, as it takes care of these details. |
|
|
996 | |
|
|
997 | This variable is mainly useful for modules that can do something useful |
|
|
998 | when AnyEvent is used and thus want to know when it is initialised, but do |
|
|
999 | not need to even load it by default. This array provides the means to hook |
|
|
1000 | into AnyEvent passively, without loading it. |
|
|
1001 | |
|
|
1002 | Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used |
|
|
1003 | together, you could put this into Coro (this is the actual code used by |
|
|
1004 | Coro to accomplish this): |
|
|
1005 | |
|
|
1006 | if (defined $AnyEvent::MODEL) { |
|
|
1007 | # AnyEvent already initialised, so load Coro::AnyEvent |
|
|
1008 | require Coro::AnyEvent; |
|
|
1009 | } else { |
|
|
1010 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
|
|
1011 | # as soon as it is |
|
|
1012 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
|
|
1013 | } |
574 | |
1014 | |
575 | =back |
1015 | =back |
576 | |
1016 | |
577 | =head1 WHAT TO DO IN A MODULE |
1017 | =head1 WHAT TO DO IN A MODULE |
578 | |
1018 | |
… | |
… | |
589 | because it will stall the whole program, and the whole point of using |
1029 | because it will stall the whole program, and the whole point of using |
590 | events is to stay interactive. |
1030 | events is to stay interactive. |
591 | |
1031 | |
592 | It is fine, however, to call C<< ->recv >> when the user of your module |
1032 | It is fine, however, to call C<< ->recv >> when the user of your module |
593 | requests it (i.e. if you create a http request object ad have a method |
1033 | requests it (i.e. if you create a http request object ad have a method |
594 | called C<results> that returns the results, it should call C<< ->recv >> |
1034 | called C<results> that returns the results, it may call C<< ->recv >> |
595 | freely, as the user of your module knows what she is doing. always). |
1035 | freely, as the user of your module knows what she is doing. Always). |
596 | |
1036 | |
597 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
1037 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
598 | |
1038 | |
599 | There will always be a single main program - the only place that should |
1039 | There will always be a single main program - the only place that should |
600 | dictate which event model to use. |
1040 | dictate which event model to use. |
601 | |
1041 | |
602 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
1042 | If the program is not event-based, it need not do anything special, even |
603 | do anything special (it does not need to be event-based) and let AnyEvent |
1043 | when it depends on a module that uses an AnyEvent. If the program itself |
604 | decide which implementation to chose if some module relies on it. |
1044 | uses AnyEvent, but does not care which event loop is used, all it needs |
|
|
1045 | to do is C<use AnyEvent>. In either case, AnyEvent will choose the best |
|
|
1046 | available loop implementation. |
605 | |
1047 | |
606 | If the main program relies on a specific event model. For example, in |
1048 | If the main program relies on a specific event model - for example, in |
607 | Gtk2 programs you have to rely on the Glib module. You should load the |
1049 | Gtk2 programs you have to rely on the Glib module - you should load the |
608 | event module before loading AnyEvent or any module that uses it: generally |
1050 | event module before loading AnyEvent or any module that uses it: generally |
609 | speaking, you should load it as early as possible. The reason is that |
1051 | speaking, you should load it as early as possible. The reason is that |
610 | modules might create watchers when they are loaded, and AnyEvent will |
1052 | modules might create watchers when they are loaded, and AnyEvent will |
611 | decide on the event model to use as soon as it creates watchers, and it |
1053 | decide on the event model to use as soon as it creates watchers, and it |
612 | might chose the wrong one unless you load the correct one yourself. |
1054 | might choose the wrong one unless you load the correct one yourself. |
613 | |
1055 | |
614 | You can chose to use a rather inefficient pure-perl implementation by |
1056 | You can chose to use a pure-perl implementation by loading the |
615 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
1057 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
616 | behaviour everywhere, but letting AnyEvent chose is generally better. |
1058 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
1059 | |
|
|
1060 | =head2 MAINLOOP EMULATION |
|
|
1061 | |
|
|
1062 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
1063 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
1064 | |
|
|
1065 | In that case, you can use a condition variable like this: |
|
|
1066 | |
|
|
1067 | AnyEvent->condvar->recv; |
|
|
1068 | |
|
|
1069 | This has the effect of entering the event loop and looping forever. |
|
|
1070 | |
|
|
1071 | Note that usually your program has some exit condition, in which case |
|
|
1072 | it is better to use the "traditional" approach of storing a condition |
|
|
1073 | variable somewhere, waiting for it, and sending it when the program should |
|
|
1074 | exit cleanly. |
|
|
1075 | |
617 | |
1076 | |
618 | =head1 OTHER MODULES |
1077 | =head1 OTHER MODULES |
619 | |
1078 | |
620 | The following is a non-exhaustive list of additional modules that use |
1079 | The following is a non-exhaustive list of additional modules that use |
621 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
1080 | AnyEvent as a client and can therefore be mixed easily with other AnyEvent |
622 | in the same program. Some of the modules come with AnyEvent, some are |
1081 | modules and other event loops in the same program. Some of the modules |
623 | available via CPAN. |
1082 | come as part of AnyEvent, the others are available via CPAN. |
624 | |
1083 | |
625 | =over 4 |
1084 | =over 4 |
626 | |
1085 | |
627 | =item L<AnyEvent::Util> |
1086 | =item L<AnyEvent::Util> |
628 | |
1087 | |
629 | Contains various utility functions that replace often-used but blocking |
1088 | Contains various utility functions that replace often-used blocking |
630 | functions such as C<inet_aton> by event-/callback-based versions. |
1089 | functions such as C<inet_aton> with event/callback-based versions. |
|
|
1090 | |
|
|
1091 | =item L<AnyEvent::Socket> |
|
|
1092 | |
|
|
1093 | Provides various utility functions for (internet protocol) sockets, |
|
|
1094 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
1095 | connections or tcp servers, with IPv6 and SRV record support and more. |
631 | |
1096 | |
632 | =item L<AnyEvent::Handle> |
1097 | =item L<AnyEvent::Handle> |
633 | |
1098 | |
634 | Provide read and write buffers and manages watchers for reads and writes. |
1099 | Provide read and write buffers, manages watchers for reads and writes, |
|
|
1100 | supports raw and formatted I/O, I/O queued and fully transparent and |
|
|
1101 | non-blocking SSL/TLS (via L<AnyEvent::TLS>). |
|
|
1102 | |
|
|
1103 | =item L<AnyEvent::DNS> |
|
|
1104 | |
|
|
1105 | Provides rich asynchronous DNS resolver capabilities. |
|
|
1106 | |
|
|
1107 | =item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP> |
|
|
1108 | |
|
|
1109 | Implement event-based interfaces to the protocols of the same name (for |
|
|
1110 | the curious, IGS is the International Go Server and FCP is the Freenet |
|
|
1111 | Client Protocol). |
|
|
1112 | |
|
|
1113 | =item L<AnyEvent::Handle::UDP> |
|
|
1114 | |
|
|
1115 | Here be danger! |
|
|
1116 | |
|
|
1117 | As Pauli would put it, "Not only is it not right, it's not even wrong!" - |
|
|
1118 | there are so many things wrong with AnyEvent::Handle::UDP, most notably |
|
|
1119 | its use of a stream-based API with a protocol that isn't streamable, that |
|
|
1120 | the only way to improve it is to delete it. |
|
|
1121 | |
|
|
1122 | It features data corruption (but typically only under load) and general |
|
|
1123 | confusion. On top, the author is not only clueless about UDP but also |
|
|
1124 | fact-resistant - some gems of his understanding: "connect doesn't work |
|
|
1125 | with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not |
|
|
1126 | packets", "I don't need to implement proper error checking as UDP doesn't |
|
|
1127 | support error checking" and so on - he doesn't even understand what's |
|
|
1128 | wrong with his module when it is explained to him. |
|
|
1129 | |
|
|
1130 | =item L<AnyEvent::DBI> |
|
|
1131 | |
|
|
1132 | Executes L<DBI> requests asynchronously in a proxy process for you, |
|
|
1133 | notifying you in an event-based way when the operation is finished. |
|
|
1134 | |
|
|
1135 | =item L<AnyEvent::AIO> |
|
|
1136 | |
|
|
1137 | Truly asynchronous (as opposed to non-blocking) I/O, should be in the |
|
|
1138 | toolbox of every event programmer. AnyEvent::AIO transparently fuses |
|
|
1139 | L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based |
|
|
1140 | file I/O, and much more. |
635 | |
1141 | |
636 | =item L<AnyEvent::HTTPD> |
1142 | =item L<AnyEvent::HTTPD> |
637 | |
1143 | |
638 | Provides a simple web application server framework. |
1144 | A simple embedded webserver. |
639 | |
|
|
640 | =item L<AnyEvent::DNS> |
|
|
641 | |
|
|
642 | Provides asynchronous DNS resolver capabilities, beyond what |
|
|
643 | L<AnyEvent::Util> offers. |
|
|
644 | |
1145 | |
645 | =item L<AnyEvent::FastPing> |
1146 | =item L<AnyEvent::FastPing> |
646 | |
1147 | |
647 | The fastest ping in the west. |
1148 | The fastest ping in the west. |
648 | |
1149 | |
649 | =item L<Net::IRC3> |
|
|
650 | |
|
|
651 | AnyEvent based IRC client module family. |
|
|
652 | |
|
|
653 | =item L<Net::XMPP2> |
|
|
654 | |
|
|
655 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
656 | |
|
|
657 | =item L<Net::FCP> |
|
|
658 | |
|
|
659 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
660 | of AnyEvent. |
|
|
661 | |
|
|
662 | =item L<Event::ExecFlow> |
|
|
663 | |
|
|
664 | High level API for event-based execution flow control. |
|
|
665 | |
|
|
666 | =item L<Coro> |
1150 | =item L<Coro> |
667 | |
1151 | |
668 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
1152 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
669 | |
1153 | |
670 | =item L<AnyEvent::AIO>, L<IO::AIO> |
|
|
671 | |
|
|
672 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
673 | programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent |
|
|
674 | together. |
|
|
675 | |
|
|
676 | =item L<AnyEvent::BDB>, L<BDB> |
|
|
677 | |
|
|
678 | Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses |
|
|
679 | IO::AIO and AnyEvent together. |
|
|
680 | |
|
|
681 | =item L<IO::Lambda> |
|
|
682 | |
|
|
683 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
684 | |
|
|
685 | =back |
1154 | =back |
686 | |
1155 | |
687 | =cut |
1156 | =cut |
688 | |
1157 | |
689 | package AnyEvent; |
1158 | package AnyEvent; |
690 | |
1159 | |
691 | no warnings; |
1160 | # basically a tuned-down version of common::sense |
692 | use strict; |
1161 | sub common_sense { |
|
|
1162 | # from common:.sense 3.3 |
|
|
1163 | ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf3\x0f\xc0\xf0\xfc\x33\x00"; |
|
|
1164 | # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl) |
|
|
1165 | $^H |= 0x00000600; |
|
|
1166 | } |
693 | |
1167 | |
|
|
1168 | BEGIN { AnyEvent::common_sense } |
|
|
1169 | |
694 | use Carp; |
1170 | use Carp (); |
695 | |
1171 | |
696 | our $VERSION = '3.6'; |
1172 | our $VERSION = '5.271'; |
697 | our $MODEL; |
1173 | our $MODEL; |
698 | |
1174 | |
699 | our $AUTOLOAD; |
1175 | our $AUTOLOAD; |
700 | our @ISA; |
1176 | our @ISA; |
701 | |
1177 | |
702 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
|
|
703 | |
|
|
704 | our @REGISTRY; |
1178 | our @REGISTRY; |
705 | |
1179 | |
|
|
1180 | our $VERBOSE; |
|
|
1181 | |
|
|
1182 | BEGIN { |
|
|
1183 | require "AnyEvent/constants.pl"; |
|
|
1184 | |
|
|
1185 | eval "sub TAINT (){" . (${^TAINT}*1) . "}"; |
|
|
1186 | |
|
|
1187 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
|
|
1188 | if ${^TAINT}; |
|
|
1189 | |
|
|
1190 | $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
|
|
1191 | |
|
|
1192 | } |
|
|
1193 | |
|
|
1194 | our $MAX_SIGNAL_LATENCY = 10; |
|
|
1195 | |
|
|
1196 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
1197 | |
|
|
1198 | { |
|
|
1199 | my $idx; |
|
|
1200 | $PROTOCOL{$_} = ++$idx |
|
|
1201 | for reverse split /\s*,\s*/, |
|
|
1202 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
1203 | } |
|
|
1204 | |
706 | my @models = ( |
1205 | my @models = ( |
707 | [EV:: => AnyEvent::Impl::EV::], |
1206 | [EV:: => AnyEvent::Impl::EV:: , 1], |
|
|
1207 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], |
|
|
1208 | # everything below here will not (normally) be autoprobed |
|
|
1209 | # as the pureperl backend should work everywhere |
|
|
1210 | # and is usually faster |
708 | [Event:: => AnyEvent::Impl::Event::], |
1211 | [Event:: => AnyEvent::Impl::Event::, 1], |
|
|
1212 | [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers |
|
|
1213 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
|
|
1214 | [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package |
709 | [Tk:: => AnyEvent::Impl::Tk::], |
1215 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
1216 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
|
|
1217 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
710 | [Wx:: => AnyEvent::Impl::POE::], |
1218 | [Wx:: => AnyEvent::Impl::POE::], |
711 | [Prima:: => AnyEvent::Impl::POE::], |
1219 | [Prima:: => AnyEvent::Impl::POE::], |
712 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
1220 | # IO::Async is just too broken - we would need workarounds for its |
713 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
1221 | # byzantine signal and broken child handling, among others. |
714 | [Glib:: => AnyEvent::Impl::Glib::], |
1222 | # IO::Async is rather hard to detect, as it doesn't have any |
715 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
1223 | # obvious default class. |
716 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
1224 | [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program |
717 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
1225 | [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
1226 | [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
1227 | [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program |
718 | ); |
1228 | ); |
719 | |
1229 | |
720 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
1230 | our %method = map +($_ => 1), |
|
|
1231 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
721 | |
1232 | |
722 | our @post_detect; |
1233 | our @post_detect; |
723 | |
1234 | |
724 | sub post_detect(&) { |
1235 | sub post_detect(&) { |
725 | my ($cb) = @_; |
1236 | my ($cb) = @_; |
726 | |
1237 | |
727 | if ($MODEL) { |
|
|
728 | $cb->(); |
|
|
729 | |
|
|
730 | 1 |
|
|
731 | } else { |
|
|
732 | push @post_detect, $cb; |
1238 | push @post_detect, $cb; |
733 | |
1239 | |
734 | defined wantarray |
1240 | defined wantarray |
735 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
1241 | ? bless \$cb, "AnyEvent::Util::postdetect" |
736 | : () |
1242 | : () |
|
|
1243 | } |
|
|
1244 | |
|
|
1245 | sub AnyEvent::Util::postdetect::DESTROY { |
|
|
1246 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
1247 | } |
|
|
1248 | |
|
|
1249 | sub detect() { |
|
|
1250 | # free some memory |
|
|
1251 | *detect = sub () { $MODEL }; |
|
|
1252 | |
|
|
1253 | local $!; # for good measure |
|
|
1254 | local $SIG{__DIE__}; |
|
|
1255 | |
|
|
1256 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
|
|
1257 | my $model = "AnyEvent::Impl::$1"; |
|
|
1258 | if (eval "require $model") { |
|
|
1259 | $MODEL = $model; |
|
|
1260 | warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; |
|
|
1261 | } else { |
|
|
1262 | warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; |
|
|
1263 | } |
737 | } |
1264 | } |
738 | } |
|
|
739 | |
1265 | |
740 | sub AnyEvent::Util::PostDetect::DESTROY { |
1266 | # check for already loaded models |
741 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
742 | } |
|
|
743 | |
|
|
744 | sub detect() { |
|
|
745 | unless ($MODEL) { |
1267 | unless ($MODEL) { |
746 | no strict 'refs'; |
1268 | for (@REGISTRY, @models) { |
747 | |
1269 | my ($package, $model) = @$_; |
748 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
1270 | if (${"$package\::VERSION"} > 0) { |
749 | my $model = "AnyEvent::Impl::$1"; |
|
|
750 | if (eval "require $model") { |
1271 | if (eval "require $model") { |
751 | $MODEL = $model; |
1272 | $MODEL = $model; |
752 | warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; |
1273 | warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2; |
753 | } else { |
1274 | last; |
754 | warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; |
1275 | } |
755 | } |
1276 | } |
756 | } |
1277 | } |
757 | |
1278 | |
758 | # check for already loaded models |
|
|
759 | unless ($MODEL) { |
1279 | unless ($MODEL) { |
|
|
1280 | # try to autoload a model |
760 | for (@REGISTRY, @models) { |
1281 | for (@REGISTRY, @models) { |
761 | my ($package, $model) = @$_; |
1282 | my ($package, $model, $autoload) = @$_; |
|
|
1283 | if ( |
|
|
1284 | $autoload |
|
|
1285 | and eval "require $package" |
762 | if (${"$package\::VERSION"} > 0) { |
1286 | and ${"$package\::VERSION"} > 0 |
763 | if (eval "require $model") { |
1287 | and eval "require $model" |
|
|
1288 | ) { |
764 | $MODEL = $model; |
1289 | $MODEL = $model; |
765 | warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; |
1290 | warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2; |
766 | last; |
1291 | last; |
767 | } |
|
|
768 | } |
1292 | } |
769 | } |
1293 | } |
770 | |
1294 | |
771 | unless ($MODEL) { |
|
|
772 | # try to load a model |
|
|
773 | |
|
|
774 | for (@REGISTRY, @models) { |
|
|
775 | my ($package, $model) = @$_; |
|
|
776 | if (eval "require $package" |
|
|
777 | and ${"$package\::VERSION"} > 0 |
|
|
778 | and eval "require $model") { |
|
|
779 | $MODEL = $model; |
|
|
780 | warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; |
|
|
781 | last; |
|
|
782 | } |
|
|
783 | } |
|
|
784 | |
|
|
785 | $MODEL |
1295 | $MODEL |
786 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
1296 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; |
787 | } |
|
|
788 | } |
1297 | } |
789 | |
|
|
790 | unshift @ISA, $MODEL; |
|
|
791 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
792 | |
|
|
793 | (shift @post_detect)->() while @post_detect; |
|
|
794 | } |
1298 | } |
|
|
1299 | |
|
|
1300 | @models = (); # free probe data |
|
|
1301 | |
|
|
1302 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
1303 | unshift @ISA, $MODEL; |
|
|
1304 | |
|
|
1305 | # now nuke some methods that are overriden by the backend. |
|
|
1306 | # SUPER is not allowed. |
|
|
1307 | for (qw(time signal child idle)) { |
|
|
1308 | undef &{"AnyEvent::Base::$_"} |
|
|
1309 | if defined &{"$MODEL\::$_"}; |
|
|
1310 | } |
|
|
1311 | |
|
|
1312 | require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; |
|
|
1313 | |
|
|
1314 | (shift @post_detect)->() while @post_detect; |
|
|
1315 | |
|
|
1316 | *post_detect = sub(&) { |
|
|
1317 | shift->(); |
|
|
1318 | |
|
|
1319 | undef |
|
|
1320 | }; |
795 | |
1321 | |
796 | $MODEL |
1322 | $MODEL |
797 | } |
1323 | } |
798 | |
1324 | |
799 | sub AUTOLOAD { |
1325 | sub AUTOLOAD { |
800 | (my $func = $AUTOLOAD) =~ s/.*://; |
1326 | (my $func = $AUTOLOAD) =~ s/.*://; |
801 | |
1327 | |
802 | $method{$func} |
1328 | $method{$func} |
803 | or croak "$func: not a valid method for AnyEvent objects"; |
1329 | or Carp::croak "$func: not a valid AnyEvent class method"; |
804 | |
1330 | |
805 | detect unless $MODEL; |
1331 | detect; |
806 | |
1332 | |
807 | my $class = shift; |
1333 | my $class = shift; |
808 | $class->$func (@_); |
1334 | $class->$func (@_); |
809 | } |
1335 | } |
810 | |
1336 | |
|
|
1337 | # utility function to dup a filehandle. this is used by many backends |
|
|
1338 | # to support binding more than one watcher per filehandle (they usually |
|
|
1339 | # allow only one watcher per fd, so we dup it to get a different one). |
|
|
1340 | sub _dupfh($$;$$) { |
|
|
1341 | my ($poll, $fh, $r, $w) = @_; |
|
|
1342 | |
|
|
1343 | # cygwin requires the fh mode to be matching, unix doesn't |
|
|
1344 | my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&"); |
|
|
1345 | |
|
|
1346 | open my $fh2, $mode, $fh |
|
|
1347 | or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,"; |
|
|
1348 | |
|
|
1349 | # we assume CLOEXEC is already set by perl in all important cases |
|
|
1350 | |
|
|
1351 | ($fh2, $rw) |
|
|
1352 | } |
|
|
1353 | |
|
|
1354 | =head1 SIMPLIFIED AE API |
|
|
1355 | |
|
|
1356 | Starting with version 5.0, AnyEvent officially supports a second, much |
|
|
1357 | simpler, API that is designed to reduce the calling, typing and memory |
|
|
1358 | overhead by using function call syntax and a fixed number of parameters. |
|
|
1359 | |
|
|
1360 | See the L<AE> manpage for details. |
|
|
1361 | |
|
|
1362 | =cut |
|
|
1363 | |
|
|
1364 | package AE; |
|
|
1365 | |
|
|
1366 | our $VERSION = $AnyEvent::VERSION; |
|
|
1367 | |
|
|
1368 | # fall back to the main API by default - backends and AnyEvent::Base |
|
|
1369 | # implementations can overwrite these. |
|
|
1370 | |
|
|
1371 | sub io($$$) { |
|
|
1372 | AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) |
|
|
1373 | } |
|
|
1374 | |
|
|
1375 | sub timer($$$) { |
|
|
1376 | AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) |
|
|
1377 | } |
|
|
1378 | |
|
|
1379 | sub signal($$) { |
|
|
1380 | AnyEvent->signal (signal => $_[0], cb => $_[1]) |
|
|
1381 | } |
|
|
1382 | |
|
|
1383 | sub child($$) { |
|
|
1384 | AnyEvent->child (pid => $_[0], cb => $_[1]) |
|
|
1385 | } |
|
|
1386 | |
|
|
1387 | sub idle($) { |
|
|
1388 | AnyEvent->idle (cb => $_[0]) |
|
|
1389 | } |
|
|
1390 | |
|
|
1391 | sub cv(;&) { |
|
|
1392 | AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) |
|
|
1393 | } |
|
|
1394 | |
|
|
1395 | sub now() { |
|
|
1396 | AnyEvent->now |
|
|
1397 | } |
|
|
1398 | |
|
|
1399 | sub now_update() { |
|
|
1400 | AnyEvent->now_update |
|
|
1401 | } |
|
|
1402 | |
|
|
1403 | sub time() { |
|
|
1404 | AnyEvent->time |
|
|
1405 | } |
|
|
1406 | |
811 | package AnyEvent::Base; |
1407 | package AnyEvent::Base; |
812 | |
1408 | |
|
|
1409 | # default implementations for many methods |
|
|
1410 | |
|
|
1411 | sub time { |
|
|
1412 | eval q{ # poor man's autoloading {} |
|
|
1413 | # probe for availability of Time::HiRes |
|
|
1414 | if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { |
|
|
1415 | warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; |
|
|
1416 | *AE::time = \&Time::HiRes::time; |
|
|
1417 | # if (eval "use POSIX (); (POSIX::times())... |
|
|
1418 | } else { |
|
|
1419 | warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; |
|
|
1420 | *AE::time = sub (){ time }; # epic fail |
|
|
1421 | } |
|
|
1422 | |
|
|
1423 | *time = sub { AE::time }; # different prototypes |
|
|
1424 | }; |
|
|
1425 | die if $@; |
|
|
1426 | |
|
|
1427 | &time |
|
|
1428 | } |
|
|
1429 | |
|
|
1430 | *now = \&time; |
|
|
1431 | |
|
|
1432 | sub now_update { } |
|
|
1433 | |
813 | # default implementation for ->condvar |
1434 | # default implementation for ->condvar |
814 | |
1435 | |
815 | sub condvar { |
1436 | sub condvar { |
|
|
1437 | eval q{ # poor man's autoloading {} |
|
|
1438 | *condvar = sub { |
816 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
1439 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" |
|
|
1440 | }; |
|
|
1441 | |
|
|
1442 | *AE::cv = sub (;&) { |
|
|
1443 | bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar" |
|
|
1444 | }; |
|
|
1445 | }; |
|
|
1446 | die if $@; |
|
|
1447 | |
|
|
1448 | &condvar |
817 | } |
1449 | } |
818 | |
1450 | |
819 | # default implementation for ->signal |
1451 | # default implementation for ->signal |
820 | |
1452 | |
821 | our %SIG_CB; |
1453 | our $HAVE_ASYNC_INTERRUPT; |
|
|
1454 | |
|
|
1455 | sub _have_async_interrupt() { |
|
|
1456 | $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} |
|
|
1457 | && eval "use Async::Interrupt 1.02 (); 1") |
|
|
1458 | unless defined $HAVE_ASYNC_INTERRUPT; |
|
|
1459 | |
|
|
1460 | $HAVE_ASYNC_INTERRUPT |
|
|
1461 | } |
|
|
1462 | |
|
|
1463 | our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); |
|
|
1464 | our (%SIG_ASY, %SIG_ASY_W); |
|
|
1465 | our ($SIG_COUNT, $SIG_TW); |
|
|
1466 | |
|
|
1467 | # install a dummy wakeup watcher to reduce signal catching latency |
|
|
1468 | # used by Impls |
|
|
1469 | sub _sig_add() { |
|
|
1470 | unless ($SIG_COUNT++) { |
|
|
1471 | # try to align timer on a full-second boundary, if possible |
|
|
1472 | my $NOW = AE::now; |
|
|
1473 | |
|
|
1474 | $SIG_TW = AE::timer |
|
|
1475 | $MAX_SIGNAL_LATENCY - ($NOW - int $NOW), |
|
|
1476 | $MAX_SIGNAL_LATENCY, |
|
|
1477 | sub { } # just for the PERL_ASYNC_CHECK |
|
|
1478 | ; |
|
|
1479 | } |
|
|
1480 | } |
|
|
1481 | |
|
|
1482 | sub _sig_del { |
|
|
1483 | undef $SIG_TW |
|
|
1484 | unless --$SIG_COUNT; |
|
|
1485 | } |
|
|
1486 | |
|
|
1487 | our $_sig_name_init; $_sig_name_init = sub { |
|
|
1488 | eval q{ # poor man's autoloading {} |
|
|
1489 | undef $_sig_name_init; |
|
|
1490 | |
|
|
1491 | if (_have_async_interrupt) { |
|
|
1492 | *sig2num = \&Async::Interrupt::sig2num; |
|
|
1493 | *sig2name = \&Async::Interrupt::sig2name; |
|
|
1494 | } else { |
|
|
1495 | require Config; |
|
|
1496 | |
|
|
1497 | my %signame2num; |
|
|
1498 | @signame2num{ split ' ', $Config::Config{sig_name} } |
|
|
1499 | = split ' ', $Config::Config{sig_num}; |
|
|
1500 | |
|
|
1501 | my @signum2name; |
|
|
1502 | @signum2name[values %signame2num] = keys %signame2num; |
|
|
1503 | |
|
|
1504 | *sig2num = sub($) { |
|
|
1505 | $_[0] > 0 ? shift : $signame2num{+shift} |
|
|
1506 | }; |
|
|
1507 | *sig2name = sub ($) { |
|
|
1508 | $_[0] > 0 ? $signum2name[+shift] : shift |
|
|
1509 | }; |
|
|
1510 | } |
|
|
1511 | }; |
|
|
1512 | die if $@; |
|
|
1513 | }; |
|
|
1514 | |
|
|
1515 | sub sig2num ($) { &$_sig_name_init; &sig2num } |
|
|
1516 | sub sig2name($) { &$_sig_name_init; &sig2name } |
822 | |
1517 | |
823 | sub signal { |
1518 | sub signal { |
|
|
1519 | eval q{ # poor man's autoloading {} |
|
|
1520 | # probe for availability of Async::Interrupt |
|
|
1521 | if (_have_async_interrupt) { |
|
|
1522 | warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8; |
|
|
1523 | |
|
|
1524 | $SIGPIPE_R = new Async::Interrupt::EventPipe; |
|
|
1525 | $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; |
|
|
1526 | |
|
|
1527 | } else { |
|
|
1528 | warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; |
|
|
1529 | |
|
|
1530 | if (AnyEvent::WIN32) { |
|
|
1531 | require AnyEvent::Util; |
|
|
1532 | |
|
|
1533 | ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); |
|
|
1534 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R; |
|
|
1535 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case |
|
|
1536 | } else { |
|
|
1537 | pipe $SIGPIPE_R, $SIGPIPE_W; |
|
|
1538 | fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R; |
|
|
1539 | fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case |
|
|
1540 | |
|
|
1541 | # not strictly required, as $^F is normally 2, but let's make sure... |
|
|
1542 | fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC; |
|
|
1543 | fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC; |
|
|
1544 | } |
|
|
1545 | |
|
|
1546 | $SIGPIPE_R |
|
|
1547 | or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; |
|
|
1548 | |
|
|
1549 | $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec; |
|
|
1550 | } |
|
|
1551 | |
|
|
1552 | *signal = $HAVE_ASYNC_INTERRUPT |
|
|
1553 | ? sub { |
824 | my (undef, %arg) = @_; |
1554 | my (undef, %arg) = @_; |
825 | |
1555 | |
|
|
1556 | # async::interrupt |
826 | my $signal = uc $arg{signal} |
1557 | my $signal = sig2num $arg{signal}; |
827 | or Carp::croak "required option 'signal' is missing"; |
|
|
828 | |
|
|
829 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
1558 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
|
|
1559 | |
|
|
1560 | $SIG_ASY{$signal} ||= new Async::Interrupt |
|
|
1561 | cb => sub { undef $SIG_EV{$signal} }, |
|
|
1562 | signal => $signal, |
|
|
1563 | pipe => [$SIGPIPE_R->filenos], |
|
|
1564 | pipe_autodrain => 0, |
|
|
1565 | ; |
|
|
1566 | |
|
|
1567 | bless [$signal, $arg{cb}], "AnyEvent::Base::signal" |
|
|
1568 | } |
|
|
1569 | : sub { |
|
|
1570 | my (undef, %arg) = @_; |
|
|
1571 | |
|
|
1572 | # pure perl |
|
|
1573 | my $signal = sig2name $arg{signal}; |
|
|
1574 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
|
|
1575 | |
830 | $SIG{$signal} ||= sub { |
1576 | $SIG{$signal} ||= sub { |
|
|
1577 | local $!; |
|
|
1578 | syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; |
|
|
1579 | undef $SIG_EV{$signal}; |
|
|
1580 | }; |
|
|
1581 | |
|
|
1582 | # can't do signal processing without introducing races in pure perl, |
|
|
1583 | # so limit the signal latency. |
|
|
1584 | _sig_add; |
|
|
1585 | |
|
|
1586 | bless [$signal, $arg{cb}], "AnyEvent::Base::signal" |
|
|
1587 | } |
|
|
1588 | ; |
|
|
1589 | |
|
|
1590 | *AnyEvent::Base::signal::DESTROY = sub { |
|
|
1591 | my ($signal, $cb) = @{$_[0]}; |
|
|
1592 | |
|
|
1593 | _sig_del; |
|
|
1594 | |
|
|
1595 | delete $SIG_CB{$signal}{$cb}; |
|
|
1596 | |
|
|
1597 | $HAVE_ASYNC_INTERRUPT |
|
|
1598 | ? delete $SIG_ASY{$signal} |
|
|
1599 | : # delete doesn't work with older perls - they then |
|
|
1600 | # print weird messages, or just unconditionally exit |
|
|
1601 | # instead of getting the default action. |
|
|
1602 | undef $SIG{$signal} |
|
|
1603 | unless keys %{ $SIG_CB{$signal} }; |
|
|
1604 | }; |
|
|
1605 | |
|
|
1606 | *_signal_exec = sub { |
|
|
1607 | $HAVE_ASYNC_INTERRUPT |
|
|
1608 | ? $SIGPIPE_R->drain |
|
|
1609 | : sysread $SIGPIPE_R, (my $dummy), 9; |
|
|
1610 | |
|
|
1611 | while (%SIG_EV) { |
|
|
1612 | for (keys %SIG_EV) { |
|
|
1613 | delete $SIG_EV{$_}; |
831 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
1614 | $_->() for values %{ $SIG_CB{$_} || {} }; |
|
|
1615 | } |
|
|
1616 | } |
|
|
1617 | }; |
832 | }; |
1618 | }; |
|
|
1619 | die if $@; |
833 | |
1620 | |
834 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
1621 | &signal |
835 | } |
|
|
836 | |
|
|
837 | sub AnyEvent::Base::Signal::DESTROY { |
|
|
838 | my ($signal, $cb) = @{$_[0]}; |
|
|
839 | |
|
|
840 | delete $SIG_CB{$signal}{$cb}; |
|
|
841 | |
|
|
842 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
|
|
843 | } |
1622 | } |
844 | |
1623 | |
845 | # default implementation for ->child |
1624 | # default implementation for ->child |
846 | |
1625 | |
847 | our %PID_CB; |
1626 | our %PID_CB; |
848 | our $CHLD_W; |
1627 | our $CHLD_W; |
849 | our $CHLD_DELAY_W; |
1628 | our $CHLD_DELAY_W; |
850 | our $PID_IDLE; |
|
|
851 | our $WNOHANG; |
1629 | our $WNOHANG; |
852 | |
1630 | |
853 | sub _child_wait { |
1631 | # used by many Impl's |
854 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
1632 | sub _emit_childstatus($$) { |
|
|
1633 | my (undef, $rpid, $rstatus) = @_; |
|
|
1634 | |
|
|
1635 | $_->($rpid, $rstatus) |
855 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
1636 | for values %{ $PID_CB{$rpid} || {} }, |
856 | (values %{ $PID_CB{0} || {} }); |
1637 | values %{ $PID_CB{0} || {} }; |
857 | } |
|
|
858 | |
|
|
859 | undef $PID_IDLE; |
|
|
860 | } |
|
|
861 | |
|
|
862 | sub _sigchld { |
|
|
863 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
864 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
865 | undef $CHLD_DELAY_W; |
|
|
866 | &_child_wait; |
|
|
867 | }); |
|
|
868 | } |
1638 | } |
869 | |
1639 | |
870 | sub child { |
1640 | sub child { |
|
|
1641 | eval q{ # poor man's autoloading {} |
|
|
1642 | *_sigchld = sub { |
|
|
1643 | my $pid; |
|
|
1644 | |
|
|
1645 | AnyEvent->_emit_childstatus ($pid, $?) |
|
|
1646 | while ($pid = waitpid -1, $WNOHANG) > 0; |
|
|
1647 | }; |
|
|
1648 | |
|
|
1649 | *child = sub { |
871 | my (undef, %arg) = @_; |
1650 | my (undef, %arg) = @_; |
872 | |
1651 | |
873 | defined (my $pid = $arg{pid} + 0) |
1652 | defined (my $pid = $arg{pid} + 0) |
874 | or Carp::croak "required option 'pid' is missing"; |
1653 | or Carp::croak "required option 'pid' is missing"; |
875 | |
1654 | |
876 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1655 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
877 | |
1656 | |
878 | unless ($WNOHANG) { |
1657 | # WNOHANG is almost cetrainly 1 everywhere |
879 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1658 | $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/ |
880 | } |
1659 | ? 1 |
|
|
1660 | : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
881 | |
1661 | |
882 | unless ($CHLD_W) { |
1662 | unless ($CHLD_W) { |
883 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1663 | $CHLD_W = AE::signal CHLD => \&_sigchld; |
884 | # child could be a zombie already, so make at least one round |
1664 | # child could be a zombie already, so make at least one round |
885 | &_sigchld; |
1665 | &_sigchld; |
886 | } |
1666 | } |
887 | |
1667 | |
888 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
1668 | bless [$pid, $arg{cb}], "AnyEvent::Base::child" |
889 | } |
1669 | }; |
890 | |
1670 | |
891 | sub AnyEvent::Base::Child::DESTROY { |
1671 | *AnyEvent::Base::child::DESTROY = sub { |
892 | my ($pid, $cb) = @{$_[0]}; |
1672 | my ($pid, $cb) = @{$_[0]}; |
893 | |
1673 | |
894 | delete $PID_CB{$pid}{$cb}; |
1674 | delete $PID_CB{$pid}{$cb}; |
895 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1675 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
896 | |
1676 | |
897 | undef $CHLD_W unless keys %PID_CB; |
1677 | undef $CHLD_W unless keys %PID_CB; |
|
|
1678 | }; |
|
|
1679 | }; |
|
|
1680 | die if $@; |
|
|
1681 | |
|
|
1682 | &child |
|
|
1683 | } |
|
|
1684 | |
|
|
1685 | # idle emulation is done by simply using a timer, regardless |
|
|
1686 | # of whether the process is idle or not, and not letting |
|
|
1687 | # the callback use more than 50% of the time. |
|
|
1688 | sub idle { |
|
|
1689 | eval q{ # poor man's autoloading {} |
|
|
1690 | *idle = sub { |
|
|
1691 | my (undef, %arg) = @_; |
|
|
1692 | |
|
|
1693 | my ($cb, $w, $rcb) = $arg{cb}; |
|
|
1694 | |
|
|
1695 | $rcb = sub { |
|
|
1696 | if ($cb) { |
|
|
1697 | $w = _time; |
|
|
1698 | &$cb; |
|
|
1699 | $w = _time - $w; |
|
|
1700 | |
|
|
1701 | # never use more then 50% of the time for the idle watcher, |
|
|
1702 | # within some limits |
|
|
1703 | $w = 0.0001 if $w < 0.0001; |
|
|
1704 | $w = 5 if $w > 5; |
|
|
1705 | |
|
|
1706 | $w = AE::timer $w, 0, $rcb; |
|
|
1707 | } else { |
|
|
1708 | # clean up... |
|
|
1709 | undef $w; |
|
|
1710 | undef $rcb; |
|
|
1711 | } |
|
|
1712 | }; |
|
|
1713 | |
|
|
1714 | $w = AE::timer 0.05, 0, $rcb; |
|
|
1715 | |
|
|
1716 | bless \\$cb, "AnyEvent::Base::idle" |
|
|
1717 | }; |
|
|
1718 | |
|
|
1719 | *AnyEvent::Base::idle::DESTROY = sub { |
|
|
1720 | undef $${$_[0]}; |
|
|
1721 | }; |
|
|
1722 | }; |
|
|
1723 | die if $@; |
|
|
1724 | |
|
|
1725 | &idle |
898 | } |
1726 | } |
899 | |
1727 | |
900 | package AnyEvent::CondVar; |
1728 | package AnyEvent::CondVar; |
901 | |
1729 | |
902 | our @ISA = AnyEvent::CondVar::Base::; |
1730 | our @ISA = AnyEvent::CondVar::Base::; |
903 | |
1731 | |
|
|
1732 | # only to be used for subclassing |
|
|
1733 | sub new { |
|
|
1734 | my $class = shift; |
|
|
1735 | bless AnyEvent->condvar (@_), $class |
|
|
1736 | } |
|
|
1737 | |
904 | package AnyEvent::CondVar::Base; |
1738 | package AnyEvent::CondVar::Base; |
|
|
1739 | |
|
|
1740 | #use overload |
|
|
1741 | # '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1742 | # fallback => 1; |
|
|
1743 | |
|
|
1744 | # save 300+ kilobytes by dirtily hardcoding overloading |
|
|
1745 | ${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching. |
|
|
1746 | *{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod." |
|
|
1747 | *{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{} |
|
|
1748 | ${'AnyEvent::CondVar::Base::()'} = 1; # fallback |
|
|
1749 | |
|
|
1750 | our $WAITING; |
905 | |
1751 | |
906 | sub _send { |
1752 | sub _send { |
907 | # nop |
1753 | # nop |
908 | } |
1754 | } |
909 | |
1755 | |
… | |
… | |
922 | sub ready { |
1768 | sub ready { |
923 | $_[0]{_ae_sent} |
1769 | $_[0]{_ae_sent} |
924 | } |
1770 | } |
925 | |
1771 | |
926 | sub _wait { |
1772 | sub _wait { |
|
|
1773 | $WAITING |
|
|
1774 | and !$_[0]{_ae_sent} |
|
|
1775 | and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected"; |
|
|
1776 | |
|
|
1777 | local $WAITING = 1; |
927 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
1778 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
928 | } |
1779 | } |
929 | |
1780 | |
930 | sub recv { |
1781 | sub recv { |
931 | $_[0]->_wait; |
1782 | $_[0]->_wait; |
… | |
… | |
933 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
1784 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
934 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
1785 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
935 | } |
1786 | } |
936 | |
1787 | |
937 | sub cb { |
1788 | sub cb { |
938 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
1789 | my $cv = shift; |
|
|
1790 | |
|
|
1791 | @_ |
|
|
1792 | and $cv->{_ae_cb} = shift |
|
|
1793 | and $cv->{_ae_sent} |
|
|
1794 | and (delete $cv->{_ae_cb})->($cv); |
|
|
1795 | |
939 | $_[0]{_ae_cb} |
1796 | $cv->{_ae_cb} |
940 | } |
1797 | } |
941 | |
1798 | |
942 | sub begin { |
1799 | sub begin { |
943 | ++$_[0]{_ae_counter}; |
1800 | ++$_[0]{_ae_counter}; |
944 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
1801 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
… | |
… | |
950 | } |
1807 | } |
951 | |
1808 | |
952 | # undocumented/compatibility with pre-3.4 |
1809 | # undocumented/compatibility with pre-3.4 |
953 | *broadcast = \&send; |
1810 | *broadcast = \&send; |
954 | *wait = \&_wait; |
1811 | *wait = \&_wait; |
|
|
1812 | |
|
|
1813 | =head1 ERROR AND EXCEPTION HANDLING |
|
|
1814 | |
|
|
1815 | In general, AnyEvent does not do any error handling - it relies on the |
|
|
1816 | caller to do that if required. The L<AnyEvent::Strict> module (see also |
|
|
1817 | the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict |
|
|
1818 | checking of all AnyEvent methods, however, which is highly useful during |
|
|
1819 | development. |
|
|
1820 | |
|
|
1821 | As for exception handling (i.e. runtime errors and exceptions thrown while |
|
|
1822 | executing a callback), this is not only highly event-loop specific, but |
|
|
1823 | also not in any way wrapped by this module, as this is the job of the main |
|
|
1824 | program. |
|
|
1825 | |
|
|
1826 | The pure perl event loop simply re-throws the exception (usually |
|
|
1827 | within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<< |
|
|
1828 | $Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and |
|
|
1829 | so on. |
|
|
1830 | |
|
|
1831 | =head1 ENVIRONMENT VARIABLES |
|
|
1832 | |
|
|
1833 | The following environment variables are used by this module or its |
|
|
1834 | submodules. |
|
|
1835 | |
|
|
1836 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
1837 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
1838 | enabled. |
|
|
1839 | |
|
|
1840 | =over 4 |
|
|
1841 | |
|
|
1842 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
1843 | |
|
|
1844 | By default, AnyEvent will be completely silent except in fatal |
|
|
1845 | conditions. You can set this environment variable to make AnyEvent more |
|
|
1846 | talkative. |
|
|
1847 | |
|
|
1848 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
1849 | conditions, such as not being able to load the event model specified by |
|
|
1850 | C<PERL_ANYEVENT_MODEL>. |
|
|
1851 | |
|
|
1852 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
1853 | model it chooses. |
|
|
1854 | |
|
|
1855 | When set to C<8> or higher, then AnyEvent will report extra information on |
|
|
1856 | which optional modules it loads and how it implements certain features. |
|
|
1857 | |
|
|
1858 | =item C<PERL_ANYEVENT_STRICT> |
|
|
1859 | |
|
|
1860 | AnyEvent does not do much argument checking by default, as thorough |
|
|
1861 | argument checking is very costly. Setting this variable to a true value |
|
|
1862 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
|
|
1863 | check the arguments passed to most method calls. If it finds any problems, |
|
|
1864 | it will croak. |
|
|
1865 | |
|
|
1866 | In other words, enables "strict" mode. |
|
|
1867 | |
|
|
1868 | Unlike C<use strict> (or its modern cousin, C<< use L<common::sense> |
|
|
1869 | >>, it is definitely recommended to keep it off in production. Keeping |
|
|
1870 | C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs |
|
|
1871 | can be very useful, however. |
|
|
1872 | |
|
|
1873 | =item C<PERL_ANYEVENT_MODEL> |
|
|
1874 | |
|
|
1875 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
1876 | auto detection and -probing kicks in. It must be a string consisting |
|
|
1877 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
1878 | and the resulting module name is loaded and if the load was successful, |
|
|
1879 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
1880 | auto detection and -probing. |
|
|
1881 | |
|
|
1882 | This functionality might change in future versions. |
|
|
1883 | |
|
|
1884 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
1885 | could start your program like this: |
|
|
1886 | |
|
|
1887 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1888 | |
|
|
1889 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1890 | |
|
|
1891 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1892 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1893 | of auto probing). |
|
|
1894 | |
|
|
1895 | Must be set to a comma-separated list of protocols or address families, |
|
|
1896 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1897 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1898 | list. |
|
|
1899 | |
|
|
1900 | This variable can effectively be used for denial-of-service attacks |
|
|
1901 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1902 | small, as the program has to handle conenction and other failures anyways. |
|
|
1903 | |
|
|
1904 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1905 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1906 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1907 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1908 | IPv6, but prefer IPv6 over IPv4. |
|
|
1909 | |
|
|
1910 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1911 | |
|
|
1912 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1913 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1914 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1915 | default. |
|
|
1916 | |
|
|
1917 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1918 | EDNS0 in its DNS requests. |
|
|
1919 | |
|
|
1920 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1921 | |
|
|
1922 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1923 | will create in parallel. |
|
|
1924 | |
|
|
1925 | =item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS> |
|
|
1926 | |
|
|
1927 | The default value for the C<max_outstanding> parameter for the default DNS |
|
|
1928 | resolver - this is the maximum number of parallel DNS requests that are |
|
|
1929 | sent to the DNS server. |
|
|
1930 | |
|
|
1931 | =item C<PERL_ANYEVENT_RESOLV_CONF> |
|
|
1932 | |
|
|
1933 | The file to use instead of F</etc/resolv.conf> (or OS-specific |
|
|
1934 | configuration) in the default resolver. When set to the empty string, no |
|
|
1935 | default config will be used. |
|
|
1936 | |
|
|
1937 | =item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. |
|
|
1938 | |
|
|
1939 | When neither C<ca_file> nor C<ca_path> was specified during |
|
|
1940 | L<AnyEvent::TLS> context creation, and either of these environment |
|
|
1941 | variables exist, they will be used to specify CA certificate locations |
|
|
1942 | instead of a system-dependent default. |
|
|
1943 | |
|
|
1944 | =item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT> |
|
|
1945 | |
|
|
1946 | When these are set to C<1>, then the respective modules are not |
|
|
1947 | loaded. Mostly good for testing AnyEvent itself. |
|
|
1948 | |
|
|
1949 | =back |
955 | |
1950 | |
956 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1951 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
957 | |
1952 | |
958 | This is an advanced topic that you do not normally need to use AnyEvent in |
1953 | This is an advanced topic that you do not normally need to use AnyEvent in |
959 | a module. This section is only of use to event loop authors who want to |
1954 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
993 | |
1988 | |
994 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
1989 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
995 | condition variables: code blocking while waiting for a condition will |
1990 | condition variables: code blocking while waiting for a condition will |
996 | C<die>. This still works with most modules/usages, and blocking calls must |
1991 | C<die>. This still works with most modules/usages, and blocking calls must |
997 | not be done in an interactive application, so it makes sense. |
1992 | not be done in an interactive application, so it makes sense. |
998 | |
|
|
999 | =head1 ENVIRONMENT VARIABLES |
|
|
1000 | |
|
|
1001 | The following environment variables are used by this module: |
|
|
1002 | |
|
|
1003 | =over 4 |
|
|
1004 | |
|
|
1005 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
1006 | |
|
|
1007 | By default, AnyEvent will be completely silent except in fatal |
|
|
1008 | conditions. You can set this environment variable to make AnyEvent more |
|
|
1009 | talkative. |
|
|
1010 | |
|
|
1011 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
1012 | conditions, such as not being able to load the event model specified by |
|
|
1013 | C<PERL_ANYEVENT_MODEL>. |
|
|
1014 | |
|
|
1015 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
1016 | model it chooses. |
|
|
1017 | |
|
|
1018 | =item C<PERL_ANYEVENT_MODEL> |
|
|
1019 | |
|
|
1020 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
1021 | autodetection and -probing kicks in. It must be a string consisting |
|
|
1022 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
1023 | and the resulting module name is loaded and if the load was successful, |
|
|
1024 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
1025 | autodetection and -probing. |
|
|
1026 | |
|
|
1027 | This functionality might change in future versions. |
|
|
1028 | |
|
|
1029 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
1030 | could start your program like this: |
|
|
1031 | |
|
|
1032 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1033 | |
|
|
1034 | =back |
|
|
1035 | |
1993 | |
1036 | =head1 EXAMPLE PROGRAM |
1994 | =head1 EXAMPLE PROGRAM |
1037 | |
1995 | |
1038 | The following program uses an I/O watcher to read data from STDIN, a timer |
1996 | The following program uses an I/O watcher to read data from STDIN, a timer |
1039 | to display a message once per second, and a condition variable to quit the |
1997 | to display a message once per second, and a condition variable to quit the |
… | |
… | |
1052 | warn "read: $input\n"; # output what has been read |
2010 | warn "read: $input\n"; # output what has been read |
1053 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
2011 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
1054 | }, |
2012 | }, |
1055 | ); |
2013 | ); |
1056 | |
2014 | |
1057 | my $time_watcher; # can only be used once |
|
|
1058 | |
|
|
1059 | sub new_timer { |
|
|
1060 | $timer = AnyEvent->timer (after => 1, cb => sub { |
2015 | my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub { |
1061 | warn "timeout\n"; # print 'timeout' about every second |
2016 | warn "timeout\n"; # print 'timeout' at most every second |
1062 | &new_timer; # and restart the time |
|
|
1063 | }); |
2017 | }); |
1064 | } |
|
|
1065 | |
|
|
1066 | new_timer; # create first timer |
|
|
1067 | |
2018 | |
1068 | $cv->recv; # wait until user enters /^q/i |
2019 | $cv->recv; # wait until user enters /^q/i |
1069 | |
2020 | |
1070 | =head1 REAL-WORLD EXAMPLE |
2021 | =head1 REAL-WORLD EXAMPLE |
1071 | |
2022 | |
… | |
… | |
1123 | syswrite $txn->{fh}, $txn->{request} |
2074 | syswrite $txn->{fh}, $txn->{request} |
1124 | or die "connection or write error"; |
2075 | or die "connection or write error"; |
1125 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
2076 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1126 | |
2077 | |
1127 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
2078 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1128 | result and signals any possible waiters that the request ahs finished: |
2079 | result and signals any possible waiters that the request has finished: |
1129 | |
2080 | |
1130 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
2081 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1131 | |
2082 | |
1132 | if (end-of-file or data complete) { |
2083 | if (end-of-file or data complete) { |
1133 | $txn->{result} = $txn->{buf}; |
2084 | $txn->{result} = $txn->{buf}; |
… | |
… | |
1141 | |
2092 | |
1142 | $txn->{finished}->recv; |
2093 | $txn->{finished}->recv; |
1143 | return $txn->{result}; |
2094 | return $txn->{result}; |
1144 | |
2095 | |
1145 | The actual code goes further and collects all errors (C<die>s, exceptions) |
2096 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1146 | that occured during request processing. The C<result> method detects |
2097 | that occurred during request processing. The C<result> method detects |
1147 | whether an exception as thrown (it is stored inside the $txn object) |
2098 | whether an exception as thrown (it is stored inside the $txn object) |
1148 | and just throws the exception, which means connection errors and other |
2099 | and just throws the exception, which means connection errors and other |
1149 | problems get reported tot he code that tries to use the result, not in a |
2100 | problems get reported to the code that tries to use the result, not in a |
1150 | random callback. |
2101 | random callback. |
1151 | |
2102 | |
1152 | All of this enables the following usage styles: |
2103 | All of this enables the following usage styles: |
1153 | |
2104 | |
1154 | 1. Blocking: |
2105 | 1. Blocking: |
… | |
… | |
1197 | of various event loops I prepared some benchmarks. |
2148 | of various event loops I prepared some benchmarks. |
1198 | |
2149 | |
1199 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
2150 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1200 | |
2151 | |
1201 | Here is a benchmark of various supported event models used natively and |
2152 | Here is a benchmark of various supported event models used natively and |
1202 | through anyevent. The benchmark creates a lot of timers (with a zero |
2153 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
1203 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
2154 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1204 | which it is), lets them fire exactly once and destroys them again. |
2155 | which it is), lets them fire exactly once and destroys them again. |
1205 | |
2156 | |
1206 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
2157 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1207 | distribution. |
2158 | distribution. It uses the L<AE> interface, which makes a real difference |
|
|
2159 | for the EV and Perl backends only. |
1208 | |
2160 | |
1209 | =head3 Explanation of the columns |
2161 | =head3 Explanation of the columns |
1210 | |
2162 | |
1211 | I<watcher> is the number of event watchers created/destroyed. Since |
2163 | I<watcher> is the number of event watchers created/destroyed. Since |
1212 | different event models feature vastly different performances, each event |
2164 | different event models feature vastly different performances, each event |
… | |
… | |
1233 | watcher. |
2185 | watcher. |
1234 | |
2186 | |
1235 | =head3 Results |
2187 | =head3 Results |
1236 | |
2188 | |
1237 | name watchers bytes create invoke destroy comment |
2189 | name watchers bytes create invoke destroy comment |
1238 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
2190 | EV/EV 100000 223 0.47 0.43 0.27 EV native interface |
1239 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
2191 | EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers |
1240 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
2192 | Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal |
1241 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
2193 | Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation |
1242 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
2194 | Event/Event 16000 516 31.16 31.84 0.82 Event native interface |
1243 | Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers |
2195 | Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers |
|
|
2196 | IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll |
|
|
2197 | IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll |
1244 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
2198 | Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour |
1245 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
2199 | Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers |
1246 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
2200 | POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event |
1247 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
2201 | POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select |
1248 | |
2202 | |
1249 | =head3 Discussion |
2203 | =head3 Discussion |
1250 | |
2204 | |
1251 | The benchmark does I<not> measure scalability of the event loop very |
2205 | The benchmark does I<not> measure scalability of the event loop very |
1252 | well. For example, a select-based event loop (such as the pure perl one) |
2206 | well. For example, a select-based event loop (such as the pure perl one) |
… | |
… | |
1264 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
2218 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
1265 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU |
2219 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU |
1266 | cycles with POE. |
2220 | cycles with POE. |
1267 | |
2221 | |
1268 | C<EV> is the sole leader regarding speed and memory use, which are both |
2222 | C<EV> is the sole leader regarding speed and memory use, which are both |
1269 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
2223 | maximal/minimal, respectively. When using the L<AE> API there is zero |
|
|
2224 | overhead (when going through the AnyEvent API create is about 5-6 times |
|
|
2225 | slower, with other times being equal, so still uses far less memory than |
1270 | far less memory than any other event loop and is still faster than Event |
2226 | any other event loop and is still faster than Event natively). |
1271 | natively. |
|
|
1272 | |
2227 | |
1273 | The pure perl implementation is hit in a few sweet spots (both the |
2228 | The pure perl implementation is hit in a few sweet spots (both the |
1274 | constant timeout and the use of a single fd hit optimisations in the perl |
2229 | constant timeout and the use of a single fd hit optimisations in the perl |
1275 | interpreter and the backend itself). Nevertheless this shows that it |
2230 | interpreter and the backend itself). Nevertheless this shows that it |
1276 | adds very little overhead in itself. Like any select-based backend its |
2231 | adds very little overhead in itself. Like any select-based backend its |
1277 | performance becomes really bad with lots of file descriptors (and few of |
2232 | performance becomes really bad with lots of file descriptors (and few of |
1278 | them active), of course, but this was not subject of this benchmark. |
2233 | them active), of course, but this was not subject of this benchmark. |
1279 | |
2234 | |
1280 | The C<Event> module has a relatively high setup and callback invocation |
2235 | The C<Event> module has a relatively high setup and callback invocation |
1281 | cost, but overall scores in on the third place. |
2236 | cost, but overall scores in on the third place. |
|
|
2237 | |
|
|
2238 | C<IO::Async> performs admirably well, about on par with C<Event>, even |
|
|
2239 | when using its pure perl backend. |
1282 | |
2240 | |
1283 | C<Glib>'s memory usage is quite a bit higher, but it features a |
2241 | C<Glib>'s memory usage is quite a bit higher, but it features a |
1284 | faster callback invocation and overall ends up in the same class as |
2242 | faster callback invocation and overall ends up in the same class as |
1285 | C<Event>. However, Glib scales extremely badly, doubling the number of |
2243 | C<Event>. However, Glib scales extremely badly, doubling the number of |
1286 | watchers increases the processing time by more than a factor of four, |
2244 | watchers increases the processing time by more than a factor of four, |
… | |
… | |
1330 | |
2288 | |
1331 | =back |
2289 | =back |
1332 | |
2290 | |
1333 | =head2 BENCHMARKING THE LARGE SERVER CASE |
2291 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1334 | |
2292 | |
1335 | This benchmark atcually benchmarks the event loop itself. It works by |
2293 | This benchmark actually benchmarks the event loop itself. It works by |
1336 | creating a number of "servers": each server consists of a socketpair, a |
2294 | creating a number of "servers": each server consists of a socket pair, a |
1337 | timeout watcher that gets reset on activity (but never fires), and an I/O |
2295 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1338 | watcher waiting for input on one side of the socket. Each time the socket |
2296 | watcher waiting for input on one side of the socket. Each time the socket |
1339 | watcher reads a byte it will write that byte to a random other "server". |
2297 | watcher reads a byte it will write that byte to a random other "server". |
1340 | |
2298 | |
1341 | The effect is that there will be a lot of I/O watchers, only part of which |
2299 | The effect is that there will be a lot of I/O watchers, only part of which |
1342 | are active at any one point (so there is a constant number of active |
2300 | are active at any one point (so there is a constant number of active |
1343 | fds for each loop iterstaion, but which fds these are is random). The |
2301 | fds for each loop iteration, but which fds these are is random). The |
1344 | timeout is reset each time something is read because that reflects how |
2302 | timeout is reset each time something is read because that reflects how |
1345 | most timeouts work (and puts extra pressure on the event loops). |
2303 | most timeouts work (and puts extra pressure on the event loops). |
1346 | |
2304 | |
1347 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
2305 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1348 | (1%) are active. This mirrors the activity of large servers with many |
2306 | (1%) are active. This mirrors the activity of large servers with many |
1349 | connections, most of which are idle at any one point in time. |
2307 | connections, most of which are idle at any one point in time. |
1350 | |
2308 | |
1351 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
2309 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1352 | distribution. |
2310 | distribution. It uses the L<AE> interface, which makes a real difference |
|
|
2311 | for the EV and Perl backends only. |
1353 | |
2312 | |
1354 | =head3 Explanation of the columns |
2313 | =head3 Explanation of the columns |
1355 | |
2314 | |
1356 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
2315 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1357 | each server has a read and write socket end). |
2316 | each server has a read and write socket end). |
1358 | |
2317 | |
1359 | I<create> is the time it takes to create a socketpair (which is |
2318 | I<create> is the time it takes to create a socket pair (which is |
1360 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
2319 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1361 | |
2320 | |
1362 | I<request>, the most important value, is the time it takes to handle a |
2321 | I<request>, the most important value, is the time it takes to handle a |
1363 | single "request", that is, reading the token from the pipe and forwarding |
2322 | single "request", that is, reading the token from the pipe and forwarding |
1364 | it to another server. This includes deleting the old timeout and creating |
2323 | it to another server. This includes deleting the old timeout and creating |
1365 | a new one that moves the timeout into the future. |
2324 | a new one that moves the timeout into the future. |
1366 | |
2325 | |
1367 | =head3 Results |
2326 | =head3 Results |
1368 | |
2327 | |
1369 | name sockets create request |
2328 | name sockets create request |
1370 | EV 20000 69.01 11.16 |
2329 | EV 20000 62.66 7.99 |
1371 | Perl 20000 73.32 35.87 |
2330 | Perl 20000 68.32 32.64 |
1372 | Event 20000 212.62 257.32 |
2331 | IOAsync 20000 174.06 101.15 epoll |
1373 | Glib 20000 651.16 1896.30 |
2332 | IOAsync 20000 174.67 610.84 poll |
|
|
2333 | Event 20000 202.69 242.91 |
|
|
2334 | Glib 20000 557.01 1689.52 |
1374 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
2335 | POE 20000 341.54 12086.32 uses POE::Loop::Event |
1375 | |
2336 | |
1376 | =head3 Discussion |
2337 | =head3 Discussion |
1377 | |
2338 | |
1378 | This benchmark I<does> measure scalability and overall performance of the |
2339 | This benchmark I<does> measure scalability and overall performance of the |
1379 | particular event loop. |
2340 | particular event loop. |
… | |
… | |
1381 | EV is again fastest. Since it is using epoll on my system, the setup time |
2342 | EV is again fastest. Since it is using epoll on my system, the setup time |
1382 | is relatively high, though. |
2343 | is relatively high, though. |
1383 | |
2344 | |
1384 | Perl surprisingly comes second. It is much faster than the C-based event |
2345 | Perl surprisingly comes second. It is much faster than the C-based event |
1385 | loops Event and Glib. |
2346 | loops Event and Glib. |
|
|
2347 | |
|
|
2348 | IO::Async performs very well when using its epoll backend, and still quite |
|
|
2349 | good compared to Glib when using its pure perl backend. |
1386 | |
2350 | |
1387 | Event suffers from high setup time as well (look at its code and you will |
2351 | Event suffers from high setup time as well (look at its code and you will |
1388 | understand why). Callback invocation also has a high overhead compared to |
2352 | understand why). Callback invocation also has a high overhead compared to |
1389 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
2353 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
1390 | uses select or poll in basically all documented configurations. |
2354 | uses select or poll in basically all documented configurations. |
… | |
… | |
1437 | speed most when you have lots of watchers, not when you only have a few of |
2401 | speed most when you have lots of watchers, not when you only have a few of |
1438 | them). |
2402 | them). |
1439 | |
2403 | |
1440 | EV is again fastest. |
2404 | EV is again fastest. |
1441 | |
2405 | |
1442 | Perl again comes second. It is noticably faster than the C-based event |
2406 | Perl again comes second. It is noticeably faster than the C-based event |
1443 | loops Event and Glib, although the difference is too small to really |
2407 | loops Event and Glib, although the difference is too small to really |
1444 | matter. |
2408 | matter. |
1445 | |
2409 | |
1446 | POE also performs much better in this case, but is is still far behind the |
2410 | POE also performs much better in this case, but is is still far behind the |
1447 | others. |
2411 | others. |
… | |
… | |
1453 | =item * C-based event loops perform very well with small number of |
2417 | =item * C-based event loops perform very well with small number of |
1454 | watchers, as the management overhead dominates. |
2418 | watchers, as the management overhead dominates. |
1455 | |
2419 | |
1456 | =back |
2420 | =back |
1457 | |
2421 | |
|
|
2422 | =head2 THE IO::Lambda BENCHMARK |
|
|
2423 | |
|
|
2424 | Recently I was told about the benchmark in the IO::Lambda manpage, which |
|
|
2425 | could be misinterpreted to make AnyEvent look bad. In fact, the benchmark |
|
|
2426 | simply compares IO::Lambda with POE, and IO::Lambda looks better (which |
|
|
2427 | shouldn't come as a surprise to anybody). As such, the benchmark is |
|
|
2428 | fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't |
|
|
2429 | very optimal. But how would AnyEvent compare when used without the extra |
|
|
2430 | baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. |
|
|
2431 | |
|
|
2432 | The benchmark itself creates an echo-server, and then, for 500 times, |
|
|
2433 | connects to the echo server, sends a line, waits for the reply, and then |
|
|
2434 | creates the next connection. This is a rather bad benchmark, as it doesn't |
|
|
2435 | test the efficiency of the framework or much non-blocking I/O, but it is a |
|
|
2436 | benchmark nevertheless. |
|
|
2437 | |
|
|
2438 | name runtime |
|
|
2439 | Lambda/select 0.330 sec |
|
|
2440 | + optimized 0.122 sec |
|
|
2441 | Lambda/AnyEvent 0.327 sec |
|
|
2442 | + optimized 0.138 sec |
|
|
2443 | Raw sockets/select 0.077 sec |
|
|
2444 | POE/select, components 0.662 sec |
|
|
2445 | POE/select, raw sockets 0.226 sec |
|
|
2446 | POE/select, optimized 0.404 sec |
|
|
2447 | |
|
|
2448 | AnyEvent/select/nb 0.085 sec |
|
|
2449 | AnyEvent/EV/nb 0.068 sec |
|
|
2450 | +state machine 0.134 sec |
|
|
2451 | |
|
|
2452 | The benchmark is also a bit unfair (my fault): the IO::Lambda/POE |
|
|
2453 | benchmarks actually make blocking connects and use 100% blocking I/O, |
|
|
2454 | defeating the purpose of an event-based solution. All of the newly |
|
|
2455 | written AnyEvent benchmarks use 100% non-blocking connects (using |
|
|
2456 | AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS |
|
|
2457 | resolver), so AnyEvent is at a disadvantage here, as non-blocking connects |
|
|
2458 | generally require a lot more bookkeeping and event handling than blocking |
|
|
2459 | connects (which involve a single syscall only). |
|
|
2460 | |
|
|
2461 | The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which |
|
|
2462 | offers similar expressive power as POE and IO::Lambda, using conventional |
|
|
2463 | Perl syntax. This means that both the echo server and the client are 100% |
|
|
2464 | non-blocking, further placing it at a disadvantage. |
|
|
2465 | |
|
|
2466 | As you can see, the AnyEvent + EV combination even beats the |
|
|
2467 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
|
|
2468 | backend easily beats IO::Lambda and POE. |
|
|
2469 | |
|
|
2470 | And even the 100% non-blocking version written using the high-level (and |
|
|
2471 | slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda |
|
|
2472 | higher level ("unoptimised") abstractions by a large margin, even though |
|
|
2473 | it does all of DNS, tcp-connect and socket I/O in a non-blocking way. |
|
|
2474 | |
|
|
2475 | The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and |
|
|
2476 | F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are |
|
|
2477 | part of the IO::Lambda distribution and were used without any changes. |
|
|
2478 | |
|
|
2479 | |
|
|
2480 | =head1 SIGNALS |
|
|
2481 | |
|
|
2482 | AnyEvent currently installs handlers for these signals: |
|
|
2483 | |
|
|
2484 | =over 4 |
|
|
2485 | |
|
|
2486 | =item SIGCHLD |
|
|
2487 | |
|
|
2488 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
|
|
2489 | emulation for event loops that do not support them natively. Also, some |
|
|
2490 | event loops install a similar handler. |
|
|
2491 | |
|
|
2492 | Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then |
|
|
2493 | AnyEvent will reset it to default, to avoid losing child exit statuses. |
|
|
2494 | |
|
|
2495 | =item SIGPIPE |
|
|
2496 | |
|
|
2497 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
|
|
2498 | when AnyEvent gets loaded. |
|
|
2499 | |
|
|
2500 | The rationale for this is that AnyEvent users usually do not really depend |
|
|
2501 | on SIGPIPE delivery (which is purely an optimisation for shell use, or |
|
|
2502 | badly-written programs), but C<SIGPIPE> can cause spurious and rare |
|
|
2503 | program exits as a lot of people do not expect C<SIGPIPE> when writing to |
|
|
2504 | some random socket. |
|
|
2505 | |
|
|
2506 | The rationale for installing a no-op handler as opposed to ignoring it is |
|
|
2507 | that this way, the handler will be restored to defaults on exec. |
|
|
2508 | |
|
|
2509 | Feel free to install your own handler, or reset it to defaults. |
|
|
2510 | |
|
|
2511 | =back |
|
|
2512 | |
|
|
2513 | =cut |
|
|
2514 | |
|
|
2515 | undef $SIG{CHLD} |
|
|
2516 | if $SIG{CHLD} eq 'IGNORE'; |
|
|
2517 | |
|
|
2518 | $SIG{PIPE} = sub { } |
|
|
2519 | unless defined $SIG{PIPE}; |
|
|
2520 | |
|
|
2521 | =head1 RECOMMENDED/OPTIONAL MODULES |
|
|
2522 | |
|
|
2523 | One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and |
|
|
2524 | its built-in modules) are required to use it. |
|
|
2525 | |
|
|
2526 | That does not mean that AnyEvent won't take advantage of some additional |
|
|
2527 | modules if they are installed. |
|
|
2528 | |
|
|
2529 | This section explains which additional modules will be used, and how they |
|
|
2530 | affect AnyEvent's operation. |
|
|
2531 | |
|
|
2532 | =over 4 |
|
|
2533 | |
|
|
2534 | =item L<Async::Interrupt> |
|
|
2535 | |
|
|
2536 | This slightly arcane module is used to implement fast signal handling: To |
|
|
2537 | my knowledge, there is no way to do completely race-free and quick |
|
|
2538 | signal handling in pure perl. To ensure that signals still get |
|
|
2539 | delivered, AnyEvent will start an interval timer to wake up perl (and |
|
|
2540 | catch the signals) with some delay (default is 10 seconds, look for |
|
|
2541 | C<$AnyEvent::MAX_SIGNAL_LATENCY>). |
|
|
2542 | |
|
|
2543 | If this module is available, then it will be used to implement signal |
|
|
2544 | catching, which means that signals will not be delayed, and the event loop |
|
|
2545 | will not be interrupted regularly, which is more efficient (and good for |
|
|
2546 | battery life on laptops). |
|
|
2547 | |
|
|
2548 | This affects not just the pure-perl event loop, but also other event loops |
|
|
2549 | that have no signal handling on their own (e.g. Glib, Tk, Qt). |
|
|
2550 | |
|
|
2551 | Some event loops (POE, Event, Event::Lib) offer signal watchers natively, |
|
|
2552 | and either employ their own workarounds (POE) or use AnyEvent's workaround |
|
|
2553 | (using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt> |
|
|
2554 | does nothing for those backends. |
|
|
2555 | |
|
|
2556 | =item L<EV> |
|
|
2557 | |
|
|
2558 | This module isn't really "optional", as it is simply one of the backend |
|
|
2559 | event loops that AnyEvent can use. However, it is simply the best event |
|
|
2560 | loop available in terms of features, speed and stability: It supports |
|
|
2561 | the AnyEvent API optimally, implements all the watcher types in XS, does |
|
|
2562 | automatic timer adjustments even when no monotonic clock is available, |
|
|
2563 | can take avdantage of advanced kernel interfaces such as C<epoll> and |
|
|
2564 | C<kqueue>, and is the fastest backend I<by far>. You can even embed |
|
|
2565 | L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>). |
|
|
2566 | |
|
|
2567 | If you only use backends that rely on another event loop (e.g. C<Tk>), |
|
|
2568 | then this module will do nothing for you. |
|
|
2569 | |
|
|
2570 | =item L<Guard> |
|
|
2571 | |
|
|
2572 | The guard module, when used, will be used to implement |
|
|
2573 | C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a |
|
|
2574 | lot less memory), but otherwise doesn't affect guard operation much. It is |
|
|
2575 | purely used for performance. |
|
|
2576 | |
|
|
2577 | =item L<JSON> and L<JSON::XS> |
|
|
2578 | |
|
|
2579 | One of these modules is required when you want to read or write JSON data |
|
|
2580 | via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take |
|
|
2581 | advantage of the ultra-high-speed L<JSON::XS> module when it is installed. |
|
|
2582 | |
|
|
2583 | =item L<Net::SSLeay> |
|
|
2584 | |
|
|
2585 | Implementing TLS/SSL in Perl is certainly interesting, but not very |
|
|
2586 | worthwhile: If this module is installed, then L<AnyEvent::Handle> (with |
|
|
2587 | the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL. |
|
|
2588 | |
|
|
2589 | =item L<Time::HiRes> |
|
|
2590 | |
|
|
2591 | This module is part of perl since release 5.008. It will be used when the |
|
|
2592 | chosen event library does not come with a timing source of its own. The |
|
|
2593 | pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to |
|
|
2594 | try to use a monotonic clock for timing stability. |
|
|
2595 | |
|
|
2596 | =back |
|
|
2597 | |
1458 | |
2598 | |
1459 | =head1 FORK |
2599 | =head1 FORK |
1460 | |
2600 | |
1461 | Most event libraries are not fork-safe. The ones who are usually are |
2601 | Most event libraries are not fork-safe. The ones who are usually are |
1462 | because they rely on inefficient but fork-safe C<select> or C<poll> |
2602 | because they rely on inefficient but fork-safe C<select> or C<poll> calls |
1463 | calls. Only L<EV> is fully fork-aware. |
2603 | - higher performance APIs such as BSD's kqueue or the dreaded Linux epoll |
|
|
2604 | are usually badly thought-out hacks that are incompatible with fork in |
|
|
2605 | one way or another. Only L<EV> is fully fork-aware and ensures that you |
|
|
2606 | continue event-processing in both parent and child (or both, if you know |
|
|
2607 | what you are doing). |
|
|
2608 | |
|
|
2609 | This means that, in general, you cannot fork and do event processing in |
|
|
2610 | the child if the event library was initialised before the fork (which |
|
|
2611 | usually happens when the first AnyEvent watcher is created, or the library |
|
|
2612 | is loaded). |
1464 | |
2613 | |
1465 | If you have to fork, you must either do so I<before> creating your first |
2614 | If you have to fork, you must either do so I<before> creating your first |
1466 | watcher OR you must not use AnyEvent at all in the child. |
2615 | watcher OR you must not use AnyEvent at all in the child OR you must do |
|
|
2616 | something completely out of the scope of AnyEvent. |
|
|
2617 | |
|
|
2618 | The problem of doing event processing in the parent I<and> the child |
|
|
2619 | is much more complicated: even for backends that I<are> fork-aware or |
|
|
2620 | fork-safe, their behaviour is not usually what you want: fork clones all |
|
|
2621 | watchers, that means all timers, I/O watchers etc. are active in both |
|
|
2622 | parent and child, which is almost never what you want. USing C<exec> |
|
|
2623 | to start worker children from some kind of manage rprocess is usually |
|
|
2624 | preferred, because it is much easier and cleaner, at the expense of having |
|
|
2625 | to have another binary. |
1467 | |
2626 | |
1468 | |
2627 | |
1469 | =head1 SECURITY CONSIDERATIONS |
2628 | =head1 SECURITY CONSIDERATIONS |
1470 | |
2629 | |
1471 | AnyEvent can be forced to load any event model via |
2630 | AnyEvent can be forced to load any event model via |
… | |
… | |
1476 | specified in the variable. |
2635 | specified in the variable. |
1477 | |
2636 | |
1478 | You can make AnyEvent completely ignore this variable by deleting it |
2637 | You can make AnyEvent completely ignore this variable by deleting it |
1479 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
2638 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1480 | |
2639 | |
1481 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
2640 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1482 | |
2641 | |
1483 | use AnyEvent; |
2642 | use AnyEvent; |
1484 | |
2643 | |
1485 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
2644 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1486 | be used to probe what backend is used and gain other information (which is |
2645 | be used to probe what backend is used and gain other information (which is |
1487 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
2646 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
|
|
2647 | $ENV{PERL_ANYEVENT_STRICT}. |
|
|
2648 | |
|
|
2649 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
2650 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
2651 | enabled. |
|
|
2652 | |
|
|
2653 | |
|
|
2654 | =head1 BUGS |
|
|
2655 | |
|
|
2656 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
|
|
2657 | to work around. If you suffer from memleaks, first upgrade to Perl 5.10 |
|
|
2658 | and check wether the leaks still show up. (Perl 5.10.0 has other annoying |
|
|
2659 | memleaks, such as leaking on C<map> and C<grep> but it is usually not as |
|
|
2660 | pronounced). |
1488 | |
2661 | |
1489 | |
2662 | |
1490 | =head1 SEE ALSO |
2663 | =head1 SEE ALSO |
|
|
2664 | |
|
|
2665 | Tutorial/Introduction: L<AnyEvent::Intro>. |
|
|
2666 | |
|
|
2667 | FAQ: L<AnyEvent::FAQ>. |
|
|
2668 | |
|
|
2669 | Utility functions: L<AnyEvent::Util>. |
1491 | |
2670 | |
1492 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
2671 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1493 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
2672 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1494 | |
2673 | |
1495 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
2674 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1496 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
2675 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1497 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
2676 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1498 | L<AnyEvent::Impl::POE>. |
2677 | L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>. |
|
|
2678 | |
|
|
2679 | Non-blocking file handles, sockets, TCP clients and |
|
|
2680 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. |
1499 | |
2681 | |
1500 | Asynchronous DNS: L<AnyEvent::DNS>. |
2682 | Asynchronous DNS: L<AnyEvent::DNS>. |
1501 | |
2683 | |
1502 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
2684 | Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV L<Coro::Event >, |
1503 | |
2685 | |
1504 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
2686 | Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>, |
|
|
2687 | L<AnyEvent::HTTP>. |
1505 | |
2688 | |
1506 | |
2689 | |
1507 | =head1 AUTHOR |
2690 | =head1 AUTHOR |
1508 | |
2691 | |
1509 | Marc Lehmann <schmorp@schmorp.de> |
2692 | Marc Lehmann <schmorp@schmorp.de> |
1510 | http://home.schmorp.de/ |
2693 | http://home.schmorp.de/ |
1511 | |
2694 | |
1512 | =cut |
2695 | =cut |
1513 | |
2696 | |
1514 | 1 |
2697 | 1 |
1515 | |
2698 | |