1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - provide framework for multiple event loops |
4 | |
4 | |
5 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported |
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6 | event loops. |
6 | |
7 | |
7 | =head1 SYNOPSIS |
8 | =head1 SYNOPSIS |
8 | |
9 | |
9 | use AnyEvent; |
10 | use AnyEvent; |
10 | |
11 | |
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12 | # file descriptor readable |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
13 | my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); |
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14 | |
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15 | # one-shot or repeating timers |
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16 | my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); |
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17 | my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... |
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18 | |
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19 | print AnyEvent->now; # prints current event loop time |
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20 | print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. |
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21 | |
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22 | # POSIX signal |
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23 | my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); |
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24 | |
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25 | # child process exit |
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26 | my $w = AnyEvent->child (pid => $pid, cb => sub { |
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27 | my ($pid, $status) = @_; |
12 | ... |
28 | ... |
13 | }); |
29 | }); |
14 | |
30 | |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
31 | # called when event loop idle (if applicable) |
16 | ... |
32 | my $w = AnyEvent->idle (cb => sub { ... }); |
17 | }); |
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18 | |
33 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
34 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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35 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
36 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
37 | # use a condvar in callback mode: |
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38 | $w->cb (sub { $_[0]->recv }); |
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39 | |
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40 | =head1 INTRODUCTION/TUTORIAL |
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41 | |
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42 | This manpage is mainly a reference manual. If you are interested |
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43 | in a tutorial or some gentle introduction, have a look at the |
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44 | L<AnyEvent::Intro> manpage. |
22 | |
45 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
46 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
47 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
48 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
49 | nowadays. So what is different about AnyEvent? |
27 | |
50 | |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
51 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
29 | policy> and AnyEvent is I<small and efficient>. |
52 | policy> and AnyEvent is I<small and efficient>. |
30 | |
53 | |
31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
54 | 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 |
55 | 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, |
56 | 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, |
57 | 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 |
58 | only one event loop can be active at the same time in a process. AnyEvent |
36 | helps hiding the differences between those event loops. |
59 | cannot change this, but it can hide the differences between those event |
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60 | loops. |
37 | |
61 | |
38 | The goal of AnyEvent is to offer module authors the ability to do event |
62 | 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 |
63 | programming (waiting for I/O or timer events) without subscribing to a |
40 | religion, a way of living, and most importantly: without forcing your |
64 | 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 |
65 | module users into the same thing by forcing them to use the same event |
42 | model you use. |
66 | model you use. |
43 | |
67 | |
44 | For modules like POE or IO::Async (which is a total misnomer as it is |
68 | 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 |
69 | 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 |
70 | like joining a cult: After you joined, you are dependent on them and you |
47 | cannot use anything else, as it is simply incompatible to everything that |
71 | 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 |
72 | 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. |
73 | module are I<also> forced to use the same event loop you use. |
50 | |
74 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
75 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
76 | 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 |
77 | 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, |
78 | 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 |
79 | 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 |
80 | 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 |
81 | use one of the supported event loops. It is trivial to add new event loops |
58 | event loops to AnyEvent, too, so it is future-proof). |
82 | to AnyEvent, too, so it is future-proof). |
59 | |
83 | |
60 | In addition to being free of having to use I<the one and only true event |
84 | 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 |
85 | 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 |
86 | 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 |
87 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
88 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
89 | technically possible. |
66 | |
90 | |
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91 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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92 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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93 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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94 | such as Windows) and lots of real-world knowledge and workarounds for |
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95 | platform bugs and differences. |
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96 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
97 | 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 |
98 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
99 | model, you should I<not> use this module. |
70 | |
100 | |
71 | =head1 DESCRIPTION |
101 | =head1 DESCRIPTION |
72 | |
102 | |
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78 | The interface itself is vaguely similar, but not identical to the L<Event> |
108 | The interface itself is vaguely similar, but not identical to the L<Event> |
79 | module. |
109 | module. |
80 | |
110 | |
81 | During the first call of any watcher-creation method, the module tries |
111 | 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 |
112 | to detect the currently loaded event loop by probing whether one of the |
83 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
113 | following modules is already loaded: L<EV>, |
84 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
114 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
85 | L<POE>. The first one found is used. If none are found, the module tries |
115 | L<POE>. The first one found is used. If none are found, the module tries |
86 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
116 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
87 | adaptor should always succeed) in the order given. The first one that can |
117 | adaptor should always succeed) in the order given. The first one that can |
88 | be successfully loaded will be used. If, after this, still none could be |
118 | be successfully loaded will be used. If, after this, still none could be |
… | |
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102 | starts using it, all bets are off. Maybe you should tell their authors to |
132 | starts using it, all bets are off. Maybe you should tell their authors to |
103 | use AnyEvent so their modules work together with others seamlessly... |
133 | use AnyEvent so their modules work together with others seamlessly... |
104 | |
134 | |
105 | The pure-perl implementation of AnyEvent is called |
135 | The pure-perl implementation of AnyEvent is called |
106 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
136 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
107 | explicitly. |
137 | explicitly and enjoy the high availability of that event loop :) |
108 | |
138 | |
109 | =head1 WATCHERS |
139 | =head1 WATCHERS |
110 | |
140 | |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
141 | 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 |
142 | stores relevant data for each kind of event you are waiting for, such as |
113 | the callback to call, the filehandle to watch, etc. |
143 | the callback to call, the file handle to watch, etc. |
114 | |
144 | |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
145 | These watchers are normal Perl objects with normal Perl lifetime. After |
116 | creating a watcher it will immediately "watch" for events and invoke the |
146 | 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 |
147 | callback when the event occurs (of course, only when the event model |
118 | is in control). |
148 | is in control). |
119 | |
149 | |
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150 | Note that B<callbacks must not permanently change global variables> |
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151 | potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< |
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152 | callbacks must not C<die> >>. The former is good programming practise in |
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153 | Perl and the latter stems from the fact that exception handling differs |
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154 | widely between event loops. |
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155 | |
120 | To disable the watcher you have to destroy it (e.g. by setting the |
156 | To disable the 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 |
157 | variable you store it in to C<undef> or otherwise deleting all references |
122 | to it). |
158 | to it). |
123 | |
159 | |
124 | All watchers are created by calling a method on the C<AnyEvent> class. |
160 | All watchers are created by calling a method on the C<AnyEvent> class. |
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126 | Many watchers either are used with "recursion" (repeating timers for |
162 | Many watchers either are used with "recursion" (repeating timers for |
127 | example), or need to refer to their watcher object in other ways. |
163 | example), or need to refer to their watcher object in other ways. |
128 | |
164 | |
129 | An any way to achieve that is this pattern: |
165 | An any way to achieve that is this pattern: |
130 | |
166 | |
131 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
167 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
132 | # you can use $w here, for example to undef it |
168 | # you can use $w here, for example to undef it |
133 | undef $w; |
169 | undef $w; |
134 | }); |
170 | }); |
135 | |
171 | |
136 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
172 | 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 |
173 | my variables are only visible after the statement in which they are |
138 | declared. |
174 | declared. |
139 | |
175 | |
140 | =head2 I/O WATCHERS |
176 | =head2 I/O WATCHERS |
141 | |
177 | |
142 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
178 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
143 | with the following mandatory key-value pairs as arguments: |
179 | with the following mandatory key-value pairs as arguments: |
144 | |
180 | |
145 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch |
181 | C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch |
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182 | for events (AnyEvent might or might not keep a reference to this file |
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183 | handle). Note that only file handles pointing to things for which |
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184 | non-blocking operation makes sense are allowed. This includes sockets, |
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185 | most character devices, pipes, fifos and so on, but not for example files |
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186 | or block devices. |
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187 | |
146 | for events. C<poll> must be a string that is either C<r> or C<w>, |
188 | 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, |
189 | watcher waiting for "r"eadable or "w"ritable events, respectively. |
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190 | |
148 | respectively. C<cb> is the callback to invoke each time the file handle |
191 | C<cb> is the callback to invoke each time the file handle becomes ready. |
149 | becomes ready. |
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150 | |
192 | |
151 | Although the callback might get passed parameters, their value and |
193 | Although the callback might get passed parameters, their value and |
152 | presence is undefined and you cannot rely on them. Portable AnyEvent |
194 | presence is undefined and you cannot rely on them. Portable AnyEvent |
153 | callbacks cannot use arguments passed to I/O watcher callbacks. |
195 | callbacks cannot use arguments passed to I/O watcher callbacks. |
154 | |
196 | |
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158 | |
200 | |
159 | Some event loops issue spurious readyness notifications, so you should |
201 | Some event loops issue spurious readyness notifications, so you should |
160 | always use non-blocking calls when reading/writing from/to your file |
202 | always use non-blocking calls when reading/writing from/to your file |
161 | handles. |
203 | handles. |
162 | |
204 | |
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 |
205 | Example: wait for readability of STDIN, then read a line and disable the |
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206 | watcher. |
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207 | |
166 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
208 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
167 | chomp (my $input = <STDIN>); |
209 | chomp (my $input = <STDIN>); |
168 | warn "read: $input\n"; |
210 | warn "read: $input\n"; |
169 | undef $w; |
211 | undef $w; |
170 | }); |
212 | }); |
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180 | |
222 | |
181 | Although the callback might get passed parameters, their value and |
223 | Although the callback might get passed parameters, their value and |
182 | presence is undefined and you cannot rely on them. Portable AnyEvent |
224 | presence is undefined and you cannot rely on them. Portable AnyEvent |
183 | callbacks cannot use arguments passed to time watcher callbacks. |
225 | callbacks cannot use arguments passed to time watcher callbacks. |
184 | |
226 | |
185 | The timer callback will be invoked at most once: if you want a repeating |
227 | The callback will normally be invoked once only. If you specify another |
186 | timer you have to create a new watcher (this is a limitation by both Tk |
228 | parameter, C<interval>, as a strictly positive number (> 0), then the |
187 | and Glib). |
229 | callback will be invoked regularly at that interval (in fractional |
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230 | seconds) after the first invocation. If C<interval> is specified with a |
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231 | false value, then it is treated as if it were missing. |
188 | |
232 | |
189 | Example: |
233 | The callback will be rescheduled before invoking the callback, but no |
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234 | attempt is done to avoid timer drift in most backends, so the interval is |
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235 | only approximate. |
190 | |
236 | |
191 | # fire an event after 7.7 seconds |
237 | Example: fire an event after 7.7 seconds. |
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238 | |
192 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
239 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
193 | warn "timeout\n"; |
240 | warn "timeout\n"; |
194 | }); |
241 | }); |
195 | |
242 | |
196 | # to cancel the timer: |
243 | # to cancel the timer: |
197 | undef $w; |
244 | undef $w; |
198 | |
245 | |
199 | Example 2: |
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200 | |
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201 | # fire an event after 0.5 seconds, then roughly every second |
246 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
202 | my $w; |
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203 | |
247 | |
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); |
248 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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249 | warn "timeout\n"; |
207 | }; |
250 | }; |
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 | |
251 | |
212 | =head3 TIMING ISSUES |
252 | =head3 TIMING ISSUES |
213 | |
253 | |
214 | There are two ways to handle timers: based on real time (relative, "fire |
254 | 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 |
255 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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227 | timers. |
267 | timers. |
228 | |
268 | |
229 | AnyEvent always prefers relative timers, if available, matching the |
269 | AnyEvent always prefers relative timers, if available, matching the |
230 | AnyEvent API. |
270 | AnyEvent API. |
231 | |
271 | |
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272 | AnyEvent has two additional methods that return the "current time": |
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273 | |
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274 | =over 4 |
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275 | |
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276 | =item AnyEvent->time |
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277 | |
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278 | This returns the "current wallclock time" as a fractional number of |
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279 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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280 | return, and the result is guaranteed to be compatible with those). |
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281 | |
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282 | It progresses independently of any event loop processing, i.e. each call |
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283 | will check the system clock, which usually gets updated frequently. |
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284 | |
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285 | =item AnyEvent->now |
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286 | |
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287 | This also returns the "current wallclock time", but unlike C<time>, above, |
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288 | this value might change only once per event loop iteration, depending on |
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289 | the event loop (most return the same time as C<time>, above). This is the |
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290 | time that AnyEvent's timers get scheduled against. |
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291 | |
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292 | I<In almost all cases (in all cases if you don't care), this is the |
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293 | function to call when you want to know the current time.> |
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294 | |
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295 | This function is also often faster then C<< AnyEvent->time >>, and |
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296 | thus the preferred method if you want some timestamp (for example, |
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297 | L<AnyEvent::Handle> uses this to update it's activity timeouts). |
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298 | |
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299 | The rest of this section is only of relevance if you try to be very exact |
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300 | with your timing, you can skip it without bad conscience. |
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301 | |
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302 | For a practical example of when these times differ, consider L<Event::Lib> |
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303 | and L<EV> and the following set-up: |
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304 | |
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305 | The event loop is running and has just invoked one of your callback at |
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306 | time=500 (assume no other callbacks delay processing). In your callback, |
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307 | you wait a second by executing C<sleep 1> (blocking the process for a |
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308 | second) and then (at time=501) you create a relative timer that fires |
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309 | after three seconds. |
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310 | |
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311 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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312 | both return C<501>, because that is the current time, and the timer will |
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313 | be scheduled to fire at time=504 (C<501> + C<3>). |
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314 | |
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315 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
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316 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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317 | last event processing phase started. With L<EV>, your timer gets scheduled |
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318 | to run at time=503 (C<500> + C<3>). |
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319 | |
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320 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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321 | regardless of any delays introduced by event processing. However, most |
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322 | callbacks do not expect large delays in processing, so this causes a |
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323 | higher drift (and a lot more system calls to get the current time). |
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324 | |
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325 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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326 | the same time, regardless of how long event processing actually took. |
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327 | |
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328 | In either case, if you care (and in most cases, you don't), then you |
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329 | can get whatever behaviour you want with any event loop, by taking the |
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330 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
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331 | account. |
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332 | |
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333 | =item AnyEvent->now_update |
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334 | |
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335 | Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache |
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336 | the current time for each loop iteration (see the discussion of L<< |
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337 | AnyEvent->now >>, above). |
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338 | |
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339 | When a callback runs for a long time (or when the process sleeps), then |
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340 | this "current" time will differ substantially from the real time, which |
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341 | might affect timers and time-outs. |
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342 | |
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343 | When this is the case, you can call this method, which will update the |
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344 | event loop's idea of "current time". |
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345 | |
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346 | Note that updating the time I<might> cause some events to be handled. |
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347 | |
|
|
348 | =back |
|
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349 | |
232 | =head2 SIGNAL WATCHERS |
350 | =head2 SIGNAL WATCHERS |
233 | |
351 | |
234 | You can watch for signals using a signal watcher, C<signal> is the signal |
352 | 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 |
353 | I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl |
236 | be invoked whenever a signal occurs. |
354 | callback to be invoked whenever a signal occurs. |
237 | |
355 | |
238 | Although the callback might get passed parameters, their value and |
356 | Although the callback might get passed parameters, their value and |
239 | presence is undefined and you cannot rely on them. Portable AnyEvent |
357 | presence is undefined and you cannot rely on them. Portable AnyEvent |
240 | callbacks cannot use arguments passed to signal watcher callbacks. |
358 | callbacks cannot use arguments passed to signal watcher callbacks. |
241 | |
359 | |
242 | Multiple signal occurances can be clumped together into one callback |
360 | Multiple signal occurrences can be clumped together into one callback |
243 | invocation, and callback invocation will be synchronous. synchronous means |
361 | invocation, and callback invocation will be synchronous. Synchronous means |
244 | that it might take a while until the signal gets handled by the process, |
362 | 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. |
363 | but it is guaranteed not to interrupt any other callbacks. |
246 | |
364 | |
247 | The main advantage of using these watchers is that you can share a signal |
365 | The main advantage of using these watchers is that you can share a signal |
248 | between multiple watchers. |
366 | between multiple watchers. |
249 | |
367 | |
250 | This watcher might use C<%SIG>, so programs overwriting those signals |
368 | This watcher might use C<%SIG>, so programs overwriting those signals |
… | |
… | |
257 | =head2 CHILD PROCESS WATCHERS |
375 | =head2 CHILD PROCESS WATCHERS |
258 | |
376 | |
259 | You can also watch on a child process exit and catch its exit status. |
377 | You can also watch on a child process exit and catch its exit status. |
260 | |
378 | |
261 | The child process is specified by the C<pid> argument (if set to C<0>, it |
379 | The child process is specified by the C<pid> argument (if set to C<0>, it |
262 | watches for any child process exit). The watcher will trigger as often |
380 | watches for any child process exit). The watcher will triggered only when |
263 | as status change for the child are received. This works by installing a |
381 | the child process has finished and an exit status is available, not on |
264 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
382 | any trace events (stopped/continued). |
265 | and exit status (as returned by waitpid), so unlike other watcher types, |
383 | |
266 | you I<can> rely on child watcher callback arguments. |
384 | The callback will be called with the pid and exit status (as returned by |
|
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385 | waitpid), so unlike other watcher types, you I<can> rely on child watcher |
|
|
386 | callback arguments. |
|
|
387 | |
|
|
388 | This watcher type works by installing a signal handler for C<SIGCHLD>, |
|
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389 | and since it cannot be shared, nothing else should use SIGCHLD or reap |
|
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390 | random child processes (waiting for specific child processes, e.g. inside |
|
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391 | C<system>, is just fine). |
267 | |
392 | |
268 | There is a slight catch to child watchers, however: you usually start them |
393 | 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 |
394 | I<after> the child process was created, and this means the process could |
270 | have exited already (and no SIGCHLD will be sent anymore). |
395 | have exited already (and no SIGCHLD will be sent anymore). |
271 | |
396 | |
272 | Not all event models handle this correctly (POE doesn't), but even for |
397 | Not all event models handle this correctly (neither POE nor IO::Async do, |
|
|
398 | 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 |
399 | 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). |
400 | the process exits (i.e. before you fork in the first place). AnyEvent's |
|
|
401 | pure perl event loop handles all cases correctly regardless of when you |
|
|
402 | start the watcher. |
275 | |
403 | |
276 | This means you cannot create a child watcher as the very first thing in an |
404 | 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 |
405 | 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>). |
406 | watcher before you C<fork> the child (alternatively, you can call |
|
|
407 | C<AnyEvent::detect>). |
279 | |
408 | |
280 | Example: fork a process and wait for it |
409 | Example: fork a process and wait for it |
281 | |
410 | |
282 | my $done = AnyEvent->condvar; |
411 | my $done = AnyEvent->condvar; |
283 | |
412 | |
284 | AnyEvent::detect; # force event module to be initialised |
|
|
285 | |
|
|
286 | my $pid = fork or exit 5; |
413 | my $pid = fork or exit 5; |
287 | |
414 | |
288 | my $w = AnyEvent->child ( |
415 | my $w = AnyEvent->child ( |
289 | pid => $pid, |
416 | pid => $pid, |
290 | cb => sub { |
417 | cb => sub { |
291 | my ($pid, $status) = @_; |
418 | my ($pid, $status) = @_; |
292 | warn "pid $pid exited with status $status"; |
419 | warn "pid $pid exited with status $status"; |
293 | $done->broadcast; |
420 | $done->send; |
294 | }, |
421 | }, |
295 | ); |
422 | ); |
296 | |
423 | |
297 | # do something else, then wait for process exit |
424 | # do something else, then wait for process exit |
298 | $done->wait; |
425 | $done->recv; |
|
|
426 | |
|
|
427 | =head2 IDLE WATCHERS |
|
|
428 | |
|
|
429 | Sometimes there is a need to do something, but it is not so important |
|
|
430 | to do it instantly, but only when there is nothing better to do. This |
|
|
431 | "nothing better to do" is usually defined to be "no other events need |
|
|
432 | attention by the event loop". |
|
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433 | |
|
|
434 | Idle watchers ideally get invoked when the event loop has nothing |
|
|
435 | better to do, just before it would block the process to wait for new |
|
|
436 | events. Instead of blocking, the idle watcher is invoked. |
|
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437 | |
|
|
438 | Most event loops unfortunately do not really support idle watchers (only |
|
|
439 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
|
|
440 | will simply call the callback "from time to time". |
|
|
441 | |
|
|
442 | Example: read lines from STDIN, but only process them when the |
|
|
443 | program is otherwise idle: |
|
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444 | |
|
|
445 | my @lines; # read data |
|
|
446 | my $idle_w; |
|
|
447 | my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
|
|
448 | push @lines, scalar <STDIN>; |
|
|
449 | |
|
|
450 | # start an idle watcher, if not already done |
|
|
451 | $idle_w ||= AnyEvent->idle (cb => sub { |
|
|
452 | # handle only one line, when there are lines left |
|
|
453 | if (my $line = shift @lines) { |
|
|
454 | print "handled when idle: $line"; |
|
|
455 | } else { |
|
|
456 | # otherwise disable the idle watcher again |
|
|
457 | undef $idle_w; |
|
|
458 | } |
|
|
459 | }); |
|
|
460 | }); |
299 | |
461 | |
300 | =head2 CONDITION VARIABLES |
462 | =head2 CONDITION VARIABLES |
301 | |
463 | |
302 | If you are familiar with some event loops you will know that all of them |
464 | If you are familiar with some event loops you will know that all of them |
303 | require you to run some blocking "loop", "run" or similar function that |
465 | require you to run some blocking "loop", "run" or similar function that |
… | |
… | |
309 | The instrument to do that is called a "condition variable", so called |
471 | The instrument to do that is called a "condition variable", so called |
310 | because they represent a condition that must become true. |
472 | because they represent a condition that must become true. |
311 | |
473 | |
312 | Condition variables can be created by calling the C<< AnyEvent->condvar |
474 | Condition variables can be created by calling the C<< AnyEvent->condvar |
313 | >> method, usually without arguments. The only argument pair allowed is |
475 | >> method, usually without arguments. The only argument pair allowed is |
|
|
476 | |
314 | C<cb>, which specifies a callback to be called when the condition variable |
477 | C<cb>, which specifies a callback to be called when the condition variable |
315 | becomes true. |
478 | becomes true, with the condition variable as the first argument (but not |
|
|
479 | the results). |
316 | |
480 | |
317 | After creation, the conditon variable is "false" until it becomes "true" |
481 | After creation, the condition variable is "false" until it becomes "true" |
318 | by calling the C<broadcast> method. |
482 | by calling the C<send> method (or calling the condition variable as if it |
|
|
483 | were a callback, read about the caveats in the description for the C<< |
|
|
484 | ->send >> method). |
319 | |
485 | |
320 | Condition variables are similar to callbacks, except that you can |
486 | Condition variables are similar to callbacks, except that you can |
321 | optionally wait for them. They can also be called merge points - points |
487 | optionally wait for them. They can also be called merge points - points |
322 | in time where multiple outstandign events have been processed. And yet |
488 | in time where multiple outstanding events have been processed. And yet |
323 | another way to call them is transations - each condition variable can be |
489 | another way to call them is transactions - each condition variable can be |
324 | used to represent a transaction, which finishes at some point and delivers |
490 | used to represent a transaction, which finishes at some point and delivers |
325 | a result. |
491 | a result. |
326 | |
492 | |
327 | Condition variables are very useful to signal that something has finished, |
493 | Condition variables are very useful to signal that something has finished, |
328 | for example, if you write a module that does asynchronous http requests, |
494 | for example, if you write a module that does asynchronous http requests, |
329 | then a condition variable would be the ideal candidate to signal the |
495 | then a condition variable would be the ideal candidate to signal the |
330 | availability of results. The user can either act when the callback is |
496 | availability of results. The user can either act when the callback is |
331 | called or can synchronously C<< ->wait >> for the results. |
497 | called or can synchronously C<< ->recv >> for the results. |
332 | |
498 | |
333 | You can also use them to simulate traditional event loops - for example, |
499 | You can also use them to simulate traditional event loops - for example, |
334 | you can block your main program until an event occurs - for example, you |
500 | you can block your main program until an event occurs - for example, you |
335 | could C<< ->wait >> in your main program until the user clicks the Quit |
501 | could C<< ->recv >> in your main program until the user clicks the Quit |
336 | button of your app, which would C<< ->broadcast >> the "quit" event. |
502 | button of your app, which would C<< ->send >> the "quit" event. |
337 | |
503 | |
338 | Note that condition variables recurse into the event loop - if you have |
504 | Note that condition variables recurse into the event loop - if you have |
339 | two pieces of code that call C<< ->wait >> in a round-robbin fashion, you |
505 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
340 | lose. Therefore, condition variables are good to export to your caller, but |
506 | lose. Therefore, condition variables are good to export to your caller, but |
341 | you should avoid making a blocking wait yourself, at least in callbacks, |
507 | you should avoid making a blocking wait yourself, at least in callbacks, |
342 | as this asks for trouble. |
508 | as this asks for trouble. |
343 | |
509 | |
344 | Condition variables are represented by hash refs in perl, and the keys |
510 | Condition variables are represented by hash refs in perl, and the keys |
… | |
… | |
346 | easy (it is often useful to build your own transaction class on top of |
512 | easy (it is often useful to build your own transaction class on top of |
347 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
513 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
348 | it's C<new> method in your own C<new> method. |
514 | it's C<new> method in your own C<new> method. |
349 | |
515 | |
350 | There are two "sides" to a condition variable - the "producer side" which |
516 | There are two "sides" to a condition variable - the "producer side" which |
351 | eventually calls C<< -> broadcast >>, and the "consumer side", which waits |
517 | eventually calls C<< -> send >>, and the "consumer side", which waits |
352 | for the broadcast to occur. |
518 | for the send to occur. |
353 | |
519 | |
354 | Example: |
520 | Example: wait for a timer. |
355 | |
521 | |
356 | # wait till the result is ready |
522 | # wait till the result is ready |
357 | my $result_ready = AnyEvent->condvar; |
523 | my $result_ready = AnyEvent->condvar; |
358 | |
524 | |
359 | # do something such as adding a timer |
525 | # do something such as adding a timer |
360 | # or socket watcher the calls $result_ready->broadcast |
526 | # or socket watcher the calls $result_ready->send |
361 | # when the "result" is ready. |
527 | # when the "result" is ready. |
362 | # in this case, we simply use a timer: |
528 | # in this case, we simply use a timer: |
363 | my $w = AnyEvent->timer ( |
529 | my $w = AnyEvent->timer ( |
364 | after => 1, |
530 | after => 1, |
365 | cb => sub { $result_ready->broadcast }, |
531 | cb => sub { $result_ready->send }, |
366 | ); |
532 | ); |
367 | |
533 | |
368 | # this "blocks" (while handling events) till the callback |
534 | # this "blocks" (while handling events) till the callback |
369 | # calls broadcast |
535 | # calls send |
370 | $result_ready->wait; |
536 | $result_ready->recv; |
|
|
537 | |
|
|
538 | Example: wait for a timer, but take advantage of the fact that |
|
|
539 | condition variables are also code references. |
|
|
540 | |
|
|
541 | my $done = AnyEvent->condvar; |
|
|
542 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
|
543 | $done->recv; |
|
|
544 | |
|
|
545 | Example: Imagine an API that returns a condvar and doesn't support |
|
|
546 | callbacks. This is how you make a synchronous call, for example from |
|
|
547 | the main program: |
|
|
548 | |
|
|
549 | use AnyEvent::CouchDB; |
|
|
550 | |
|
|
551 | ... |
|
|
552 | |
|
|
553 | my @info = $couchdb->info->recv; |
|
|
554 | |
|
|
555 | And this is how you would just ste a callback to be called whenever the |
|
|
556 | results are available: |
|
|
557 | |
|
|
558 | $couchdb->info->cb (sub { |
|
|
559 | my @info = $_[0]->recv; |
|
|
560 | }); |
371 | |
561 | |
372 | =head3 METHODS FOR PRODUCERS |
562 | =head3 METHODS FOR PRODUCERS |
373 | |
563 | |
374 | These methods should only be used by the producing side, i.e. the |
564 | These methods should only be used by the producing side, i.e. the |
375 | code/module that eventually broadcasts the signal. Note that it is also |
565 | code/module that eventually sends the signal. Note that it is also |
376 | the producer side which creates the condvar in most cases, but it isn't |
566 | the producer side which creates the condvar in most cases, but it isn't |
377 | uncommon for the consumer to create it as well. |
567 | uncommon for the consumer to create it as well. |
378 | |
568 | |
379 | =over 4 |
569 | =over 4 |
380 | |
570 | |
381 | =item $cv->broadcast (...) |
571 | =item $cv->send (...) |
382 | |
572 | |
383 | Flag the condition as ready - a running C<< ->wait >> and all further |
573 | Flag the condition as ready - a running C<< ->recv >> and all further |
384 | calls to C<wait> will (eventually) return after this method has been |
574 | calls to C<recv> will (eventually) return after this method has been |
385 | called. If nobody is waiting the broadcast will be remembered. |
575 | called. If nobody is waiting the send will be remembered. |
386 | |
576 | |
387 | If a callback has been set on the condition variable, it is called |
577 | If a callback has been set on the condition variable, it is called |
388 | immediately from within broadcast. |
578 | immediately from within send. |
389 | |
579 | |
390 | Any arguments passed to the C<broadcast> call will be returned by all |
580 | Any arguments passed to the C<send> call will be returned by all |
391 | future C<< ->wait >> calls. |
581 | future C<< ->recv >> calls. |
|
|
582 | |
|
|
583 | Condition variables are overloaded so one can call them directly |
|
|
584 | (as a code reference). Calling them directly is the same as calling |
|
|
585 | C<send>. Note, however, that many C-based event loops do not handle |
|
|
586 | overloading, so as tempting as it may be, passing a condition variable |
|
|
587 | instead of a callback does not work. Both the pure perl and EV loops |
|
|
588 | support overloading, however, as well as all functions that use perl to |
|
|
589 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
|
|
590 | example). |
392 | |
591 | |
393 | =item $cv->croak ($error) |
592 | =item $cv->croak ($error) |
394 | |
593 | |
395 | Similar to broadcast, but causes all call's wait C<< ->wait >> to invoke |
594 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
396 | C<Carp::croak> with the given error message/object/scalar. |
595 | C<Carp::croak> with the given error message/object/scalar. |
397 | |
596 | |
398 | This can be used to signal any errors to the condition variable |
597 | This can be used to signal any errors to the condition variable |
399 | user/consumer. |
598 | user/consumer. |
400 | |
599 | |
… | |
… | |
407 | to use a condition variable for the whole process. |
606 | to use a condition variable for the whole process. |
408 | |
607 | |
409 | Every call to C<< ->begin >> will increment a counter, and every call to |
608 | 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 |
609 | 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 |
610 | >>, the (last) callback passed to C<begin> will be executed. That callback |
412 | is I<supposed> to call C<< ->broadcast >>, but that is not required. If no |
611 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
413 | callback was set, C<broadcast> will be called without any arguments. |
612 | callback was set, C<send> will be called without any arguments. |
414 | |
613 | |
415 | Let's clarify this with the ping example: |
614 | You can think of C<< $cv->send >> giving you an OR condition (one call |
|
|
615 | sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND |
|
|
616 | condition (all C<begin> calls must be C<end>'ed before the condvar sends). |
|
|
617 | |
|
|
618 | Let's start with a simple example: you have two I/O watchers (for example, |
|
|
619 | STDOUT and STDERR for a program), and you want to wait for both streams to |
|
|
620 | close before activating a condvar: |
416 | |
621 | |
417 | my $cv = AnyEvent->condvar; |
622 | my $cv = AnyEvent->condvar; |
418 | |
623 | |
|
|
624 | $cv->begin; # first watcher |
|
|
625 | my $w1 = AnyEvent->io (fh => $fh1, cb => sub { |
|
|
626 | defined sysread $fh1, my $buf, 4096 |
|
|
627 | or $cv->end; |
|
|
628 | }); |
|
|
629 | |
|
|
630 | $cv->begin; # second watcher |
|
|
631 | my $w2 = AnyEvent->io (fh => $fh2, cb => sub { |
|
|
632 | defined sysread $fh2, my $buf, 4096 |
|
|
633 | or $cv->end; |
|
|
634 | }); |
|
|
635 | |
|
|
636 | $cv->recv; |
|
|
637 | |
|
|
638 | This works because for every event source (EOF on file handle), there is |
|
|
639 | one call to C<begin>, so the condvar waits for all calls to C<end> before |
|
|
640 | sending. |
|
|
641 | |
|
|
642 | The ping example mentioned above is slightly more complicated, as the |
|
|
643 | there are results to be passwd back, and the number of tasks that are |
|
|
644 | begung can potentially be zero: |
|
|
645 | |
|
|
646 | my $cv = AnyEvent->condvar; |
|
|
647 | |
419 | my %result; |
648 | my %result; |
420 | $cv->begin (sub { $cv->broadcast (\%result) }); |
649 | $cv->begin (sub { $cv->send (\%result) }); |
421 | |
650 | |
422 | for my $host (@list_of_hosts) { |
651 | for my $host (@list_of_hosts) { |
423 | $cv->begin; |
652 | $cv->begin; |
424 | ping_host_then_call_callback $host, sub { |
653 | ping_host_then_call_callback $host, sub { |
425 | $result{$host} = ...; |
654 | $result{$host} = ...; |
… | |
… | |
428 | } |
657 | } |
429 | |
658 | |
430 | $cv->end; |
659 | $cv->end; |
431 | |
660 | |
432 | This code fragment supposedly pings a number of hosts and calls |
661 | This code fragment supposedly pings a number of hosts and calls |
433 | C<broadcast> after results for all then have have been gathered - in any |
662 | C<send> after results for all then have have been gathered - in any |
434 | order. To achieve this, the code issues a call to C<begin> when it starts |
663 | order. To achieve this, the code issues a call to C<begin> when it starts |
435 | each ping request and calls C<end> when it has received some result for |
664 | each ping request and calls C<end> when it has received some result for |
436 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
665 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
437 | results arrive is not relevant. |
666 | results arrive is not relevant. |
438 | |
667 | |
439 | There is an additional bracketing call to C<begin> and C<end> outside the |
668 | There is an additional bracketing call to C<begin> and C<end> outside the |
440 | loop, which serves two important purposes: first, it sets the callback |
669 | 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 |
670 | to be called once the counter reaches C<0>, and second, it ensures that |
442 | broadcast is called even when C<no> hosts are being pinged (the loop |
671 | C<send> is called even when C<no> hosts are being pinged (the loop |
443 | doesn't execute once). |
672 | doesn't execute once). |
444 | |
673 | |
445 | This is the general pattern when you "fan out" into multiple subrequests: |
674 | 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> |
675 | potentially none) 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 |
676 | 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>. |
677 | subrequest you start, call C<begin> and for each subrequest you finish, |
|
|
678 | call C<end>. |
449 | |
679 | |
450 | =back |
680 | =back |
451 | |
681 | |
452 | =head3 METHODS FOR CONSUMERS |
682 | =head3 METHODS FOR CONSUMERS |
453 | |
683 | |
454 | These methods should only be used by the consuming side, i.e. the |
684 | These methods should only be used by the consuming side, i.e. the |
455 | code awaits the condition. |
685 | code awaits the condition. |
456 | |
686 | |
457 | =item $cv->wait |
687 | =over 4 |
458 | |
688 | |
|
|
689 | =item $cv->recv |
|
|
690 | |
459 | Wait (blocking if necessary) until the C<< ->broadcast >> or C<< ->croak |
691 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
460 | >> methods have been called on c<$cv>, while servicing other watchers |
692 | >> methods have been called on c<$cv>, while servicing other watchers |
461 | normally. |
693 | normally. |
462 | |
694 | |
463 | You can only wait once on a condition - additional calls are valid but |
695 | You can only wait once on a condition - additional calls are valid but |
464 | will return immediately. |
696 | will return immediately. |
465 | |
697 | |
466 | If an error condition has been set by calling C<< ->croak >>, then this |
698 | If an error condition has been set by calling C<< ->croak >>, then this |
467 | function will call C<croak>. |
699 | function will call C<croak>. |
468 | |
700 | |
469 | In list context, all parameters passed to C<broadcast> will be returned, |
701 | In list context, all parameters passed to C<send> will be returned, |
470 | in scalar context only the first one will be returned. |
702 | in scalar context only the first one will be returned. |
471 | |
703 | |
472 | Not all event models support a blocking wait - some die in that case |
704 | Not all event models support a blocking wait - some die in that case |
473 | (programs might want to do that to stay interactive), so I<if you are |
705 | (programs might want to do that to stay interactive), so I<if you are |
474 | using this from a module, never require a blocking wait>, but let the |
706 | using this from a module, never require a blocking wait>, but let the |
475 | caller decide whether the call will block or not (for example, by coupling |
707 | caller decide whether the call will block or not (for example, by coupling |
476 | condition variables with some kind of request results and supporting |
708 | condition variables with some kind of request results and supporting |
477 | callbacks so the caller knows that getting the result will not block, |
709 | callbacks so the caller knows that getting the result will not block, |
478 | while still suppporting blocking waits if the caller so desires). |
710 | while still supporting blocking waits if the caller so desires). |
479 | |
711 | |
480 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
712 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
481 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
713 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
482 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
714 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
483 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
715 | can supply. |
484 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
485 | from different coroutines, however). |
|
|
486 | |
716 | |
|
|
717 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
718 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
719 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
720 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
721 | coroutine (one that doesn't run the event loop). |
|
|
722 | |
487 | You can ensure that C<< -wait >> never blocks by setting a callback and |
723 | You can ensure that C<< -recv >> never blocks by setting a callback and |
488 | only calling C<< ->wait >> from within that callback (or at a later |
724 | only calling C<< ->recv >> from within that callback (or at a later |
489 | time). This will work even when the event loop does not support blocking |
725 | time). This will work even when the event loop does not support blocking |
490 | waits otherwise. |
726 | waits otherwise. |
|
|
727 | |
|
|
728 | =item $bool = $cv->ready |
|
|
729 | |
|
|
730 | Returns true when the condition is "true", i.e. whether C<send> or |
|
|
731 | C<croak> have been called. |
|
|
732 | |
|
|
733 | =item $cb = $cv->cb ($cb->($cv)) |
|
|
734 | |
|
|
735 | This is a mutator function that returns the callback set and optionally |
|
|
736 | replaces it before doing so. |
|
|
737 | |
|
|
738 | The callback will be called when the condition becomes "true", i.e. when |
|
|
739 | C<send> or C<croak> are called, with the only argument being the condition |
|
|
740 | variable itself. Calling C<recv> inside the callback or at any later time |
|
|
741 | is guaranteed not to block. |
491 | |
742 | |
492 | =back |
743 | =back |
493 | |
744 | |
494 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
745 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
495 | |
746 | |
… | |
… | |
503 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
754 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
504 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
755 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
505 | |
756 | |
506 | The known classes so far are: |
757 | The known classes so far are: |
507 | |
758 | |
508 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
509 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
510 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
759 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
511 | AnyEvent::Impl::Event based on Event, second best choice. |
760 | AnyEvent::Impl::Event based on Event, second best choice. |
512 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
761 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
513 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
762 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
514 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
763 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
515 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
764 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
516 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
765 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
517 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
766 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
518 | |
767 | |
|
|
768 | # warning, support for IO::Async is only partial, as it is too broken |
|
|
769 | # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async. |
|
|
770 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs). |
|
|
771 | |
519 | There is no support for WxWidgets, as WxWidgets has no support for |
772 | There is no support for WxWidgets, as WxWidgets has no support for |
520 | watching file handles. However, you can use WxWidgets through the |
773 | watching file handles. However, you can use WxWidgets through the |
521 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
774 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
522 | second, which was considered to be too horrible to even consider for |
775 | second, which was considered to be too horrible to even consider for |
523 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
776 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
… | |
… | |
531 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
784 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
532 | if necessary. You should only call this function right before you would |
785 | if necessary. You should only call this function right before you would |
533 | have created an AnyEvent watcher anyway, that is, as late as possible at |
786 | have created an AnyEvent watcher anyway, that is, as late as possible at |
534 | runtime. |
787 | runtime. |
535 | |
788 | |
|
|
789 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
790 | |
|
|
791 | Arranges for the code block to be executed as soon as the event model is |
|
|
792 | autodetected (or immediately if this has already happened). |
|
|
793 | |
|
|
794 | If called in scalar or list context, then it creates and returns an object |
|
|
795 | that automatically removes the callback again when it is destroyed. See |
|
|
796 | L<Coro::BDB> for a case where this is useful. |
|
|
797 | |
|
|
798 | =item @AnyEvent::post_detect |
|
|
799 | |
|
|
800 | If there are any code references in this array (you can C<push> to it |
|
|
801 | before or after loading AnyEvent), then they will called directly after |
|
|
802 | the event loop has been chosen. |
|
|
803 | |
|
|
804 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
805 | if it contains a true value then the event loop has already been detected, |
|
|
806 | and the array will be ignored. |
|
|
807 | |
|
|
808 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
809 | |
536 | =back |
810 | =back |
537 | |
811 | |
538 | =head1 WHAT TO DO IN A MODULE |
812 | =head1 WHAT TO DO IN A MODULE |
539 | |
813 | |
540 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
814 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
543 | Be careful when you create watchers in the module body - AnyEvent will |
817 | Be careful when you create watchers in the module body - AnyEvent will |
544 | decide which event module to use as soon as the first method is called, so |
818 | decide which event module to use as soon as the first method is called, so |
545 | by calling AnyEvent in your module body you force the user of your module |
819 | by calling AnyEvent in your module body you force the user of your module |
546 | to load the event module first. |
820 | to load the event module first. |
547 | |
821 | |
548 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
822 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
549 | the C<< ->broadcast >> method has been called on it already. This is |
823 | the C<< ->send >> method has been called on it already. This is |
550 | because it will stall the whole program, and the whole point of using |
824 | because it will stall the whole program, and the whole point of using |
551 | events is to stay interactive. |
825 | events is to stay interactive. |
552 | |
826 | |
553 | It is fine, however, to call C<< ->wait >> when the user of your module |
827 | It is fine, however, to call C<< ->recv >> when the user of your module |
554 | requests it (i.e. if you create a http request object ad have a method |
828 | requests it (i.e. if you create a http request object ad have a method |
555 | called C<results> that returns the results, it should call C<< ->wait >> |
829 | called C<results> that returns the results, it should call C<< ->recv >> |
556 | freely, as the user of your module knows what she is doing. always). |
830 | freely, as the user of your module knows what she is doing. always). |
557 | |
831 | |
558 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
832 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
559 | |
833 | |
560 | There will always be a single main program - the only place that should |
834 | There will always be a single main program - the only place that should |
… | |
… | |
562 | |
836 | |
563 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
837 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
564 | do anything special (it does not need to be event-based) and let AnyEvent |
838 | do anything special (it does not need to be event-based) and let AnyEvent |
565 | decide which implementation to chose if some module relies on it. |
839 | decide which implementation to chose if some module relies on it. |
566 | |
840 | |
567 | If the main program relies on a specific event model. For example, in |
841 | If the main program relies on a specific event model - for example, in |
568 | Gtk2 programs you have to rely on the Glib module. You should load the |
842 | Gtk2 programs you have to rely on the Glib module - you should load the |
569 | event module before loading AnyEvent or any module that uses it: generally |
843 | event module before loading AnyEvent or any module that uses it: generally |
570 | speaking, you should load it as early as possible. The reason is that |
844 | speaking, you should load it as early as possible. The reason is that |
571 | modules might create watchers when they are loaded, and AnyEvent will |
845 | modules might create watchers when they are loaded, and AnyEvent will |
572 | decide on the event model to use as soon as it creates watchers, and it |
846 | decide on the event model to use as soon as it creates watchers, and it |
573 | might chose the wrong one unless you load the correct one yourself. |
847 | might chose the wrong one unless you load the correct one yourself. |
574 | |
848 | |
575 | You can chose to use a rather inefficient pure-perl implementation by |
849 | You can chose to use a pure-perl implementation by loading the |
576 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
850 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
577 | behaviour everywhere, but letting AnyEvent chose is generally better. |
851 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
852 | |
|
|
853 | =head2 MAINLOOP EMULATION |
|
|
854 | |
|
|
855 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
856 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
857 | |
|
|
858 | In that case, you can use a condition variable like this: |
|
|
859 | |
|
|
860 | AnyEvent->condvar->recv; |
|
|
861 | |
|
|
862 | This has the effect of entering the event loop and looping forever. |
|
|
863 | |
|
|
864 | Note that usually your program has some exit condition, in which case |
|
|
865 | it is better to use the "traditional" approach of storing a condition |
|
|
866 | variable somewhere, waiting for it, and sending it when the program should |
|
|
867 | exit cleanly. |
|
|
868 | |
578 | |
869 | |
579 | =head1 OTHER MODULES |
870 | =head1 OTHER MODULES |
580 | |
871 | |
581 | The following is a non-exhaustive list of additional modules that use |
872 | The following is a non-exhaustive list of additional modules that use |
582 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
873 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
… | |
… | |
588 | =item L<AnyEvent::Util> |
879 | =item L<AnyEvent::Util> |
589 | |
880 | |
590 | Contains various utility functions that replace often-used but blocking |
881 | Contains various utility functions that replace often-used but blocking |
591 | functions such as C<inet_aton> by event-/callback-based versions. |
882 | functions such as C<inet_aton> by event-/callback-based versions. |
592 | |
883 | |
|
|
884 | =item L<AnyEvent::Socket> |
|
|
885 | |
|
|
886 | Provides various utility functions for (internet protocol) sockets, |
|
|
887 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
888 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
889 | |
593 | =item L<AnyEvent::Handle> |
890 | =item L<AnyEvent::Handle> |
594 | |
891 | |
595 | Provide read and write buffers and manages watchers for reads and writes. |
892 | Provide read and write buffers, manages watchers for reads and writes, |
|
|
893 | supports raw and formatted I/O, I/O queued and fully transparent and |
|
|
894 | non-blocking SSL/TLS. |
596 | |
895 | |
597 | =item L<AnyEvent::Socket> |
896 | =item L<AnyEvent::DNS> |
598 | |
897 | |
599 | Provides a means to do non-blocking connects, accepts etc. |
898 | Provides rich asynchronous DNS resolver capabilities. |
|
|
899 | |
|
|
900 | =item L<AnyEvent::HTTP> |
|
|
901 | |
|
|
902 | A simple-to-use HTTP library that is capable of making a lot of concurrent |
|
|
903 | HTTP requests. |
600 | |
904 | |
601 | =item L<AnyEvent::HTTPD> |
905 | =item L<AnyEvent::HTTPD> |
602 | |
906 | |
603 | Provides a simple web application server framework. |
907 | Provides a simple web application server framework. |
604 | |
908 | |
605 | =item L<AnyEvent::DNS> |
|
|
606 | |
|
|
607 | Provides asynchronous DNS resolver capabilities, beyond what |
|
|
608 | L<AnyEvent::Util> offers. |
|
|
609 | |
|
|
610 | =item L<AnyEvent::FastPing> |
909 | =item L<AnyEvent::FastPing> |
611 | |
910 | |
612 | The fastest ping in the west. |
911 | The fastest ping in the west. |
613 | |
912 | |
|
|
913 | =item L<AnyEvent::DBI> |
|
|
914 | |
|
|
915 | Executes L<DBI> requests asynchronously in a proxy process. |
|
|
916 | |
|
|
917 | =item L<AnyEvent::AIO> |
|
|
918 | |
|
|
919 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
920 | programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent |
|
|
921 | together. |
|
|
922 | |
|
|
923 | =item L<AnyEvent::BDB> |
|
|
924 | |
|
|
925 | Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses |
|
|
926 | L<BDB> and AnyEvent together. |
|
|
927 | |
|
|
928 | =item L<AnyEvent::GPSD> |
|
|
929 | |
|
|
930 | A non-blocking interface to gpsd, a daemon delivering GPS information. |
|
|
931 | |
|
|
932 | =item L<AnyEvent::IGS> |
|
|
933 | |
|
|
934 | A non-blocking interface to the Internet Go Server protocol (used by |
|
|
935 | L<App::IGS>). |
|
|
936 | |
614 | =item L<Net::IRC3> |
937 | =item L<AnyEvent::IRC> |
615 | |
938 | |
616 | AnyEvent based IRC client module family. |
939 | AnyEvent based IRC client module family (replacing the older Net::IRC3). |
617 | |
940 | |
618 | =item L<Net::XMPP2> |
941 | =item L<Net::XMPP2> |
619 | |
942 | |
620 | AnyEvent based XMPP (Jabber protocol) module family. |
943 | AnyEvent based XMPP (Jabber protocol) module family. |
621 | |
944 | |
… | |
… | |
628 | |
951 | |
629 | High level API for event-based execution flow control. |
952 | High level API for event-based execution flow control. |
630 | |
953 | |
631 | =item L<Coro> |
954 | =item L<Coro> |
632 | |
955 | |
633 | Has special support for AnyEvent. |
956 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
634 | |
957 | |
635 | =item L<IO::Lambda> |
958 | =item L<IO::Lambda> |
636 | |
959 | |
637 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
960 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
638 | |
961 | |
639 | =item L<IO::AIO> |
|
|
640 | |
|
|
641 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
642 | programmer. Can be trivially made to use AnyEvent. |
|
|
643 | |
|
|
644 | =item L<BDB> |
|
|
645 | |
|
|
646 | Truly asynchronous Berkeley DB access. Can be trivially made to use |
|
|
647 | AnyEvent. |
|
|
648 | |
|
|
649 | =back |
962 | =back |
650 | |
963 | |
651 | =cut |
964 | =cut |
652 | |
965 | |
653 | package AnyEvent; |
966 | package AnyEvent; |
654 | |
967 | |
655 | no warnings; |
968 | no warnings; |
656 | use strict; |
969 | use strict qw(vars subs); |
657 | |
970 | |
658 | use Carp; |
971 | use Carp; |
659 | |
972 | |
660 | our $VERSION = '3.3'; |
973 | our $VERSION = 4.8; |
661 | our $MODEL; |
974 | our $MODEL; |
662 | |
975 | |
663 | our $AUTOLOAD; |
976 | our $AUTOLOAD; |
664 | our @ISA; |
977 | our @ISA; |
665 | |
978 | |
|
|
979 | our @REGISTRY; |
|
|
980 | |
|
|
981 | our $WIN32; |
|
|
982 | |
|
|
983 | BEGIN { |
|
|
984 | eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; |
|
|
985 | eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; |
|
|
986 | |
|
|
987 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
|
|
988 | if ${^TAINT}; |
|
|
989 | } |
|
|
990 | |
666 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
991 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
667 | |
992 | |
668 | our @REGISTRY; |
993 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
994 | |
|
|
995 | { |
|
|
996 | my $idx; |
|
|
997 | $PROTOCOL{$_} = ++$idx |
|
|
998 | for reverse split /\s*,\s*/, |
|
|
999 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
1000 | } |
669 | |
1001 | |
670 | my @models = ( |
1002 | my @models = ( |
671 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
672 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
673 | [EV:: => AnyEvent::Impl::EV::], |
1003 | [EV:: => AnyEvent::Impl::EV::], |
674 | [Event:: => AnyEvent::Impl::Event::], |
1004 | [Event:: => AnyEvent::Impl::Event::], |
675 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
676 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
677 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
678 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
1005 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
679 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
1006 | # everything below here will not be autoprobed |
680 | [Glib:: => AnyEvent::Impl::Glib::], |
1007 | # as the pureperl backend should work everywhere |
|
|
1008 | # and is usually faster |
|
|
1009 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
1010 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
681 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
1011 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
682 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
1012 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
683 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
1013 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
1014 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
1015 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
1016 | # IO::Async is just too broken - we would need workaorunds for its |
|
|
1017 | # byzantine signal and broken child handling, among others. |
|
|
1018 | # IO::Async is rather hard to detect, as it doesn't have any |
|
|
1019 | # obvious default class. |
|
|
1020 | # [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
1021 | # [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
1022 | # [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program |
684 | ); |
1023 | ); |
685 | |
1024 | |
686 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
1025 | our %method = map +($_ => 1), |
|
|
1026 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
|
|
1027 | |
|
|
1028 | our @post_detect; |
|
|
1029 | |
|
|
1030 | sub post_detect(&) { |
|
|
1031 | my ($cb) = @_; |
|
|
1032 | |
|
|
1033 | if ($MODEL) { |
|
|
1034 | $cb->(); |
|
|
1035 | |
|
|
1036 | 1 |
|
|
1037 | } else { |
|
|
1038 | push @post_detect, $cb; |
|
|
1039 | |
|
|
1040 | defined wantarray |
|
|
1041 | ? bless \$cb, "AnyEvent::Util::postdetect" |
|
|
1042 | : () |
|
|
1043 | } |
|
|
1044 | } |
|
|
1045 | |
|
|
1046 | sub AnyEvent::Util::postdetect::DESTROY { |
|
|
1047 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
1048 | } |
687 | |
1049 | |
688 | sub detect() { |
1050 | sub detect() { |
689 | unless ($MODEL) { |
1051 | unless ($MODEL) { |
690 | no strict 'refs'; |
1052 | no strict 'refs'; |
|
|
1053 | local $SIG{__DIE__}; |
691 | |
1054 | |
692 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
1055 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
693 | my $model = "AnyEvent::Impl::$1"; |
1056 | my $model = "AnyEvent::Impl::$1"; |
694 | if (eval "require $model") { |
1057 | if (eval "require $model") { |
695 | $MODEL = $model; |
1058 | $MODEL = $model; |
… | |
… | |
725 | last; |
1088 | last; |
726 | } |
1089 | } |
727 | } |
1090 | } |
728 | |
1091 | |
729 | $MODEL |
1092 | $MODEL |
730 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
1093 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; |
731 | } |
1094 | } |
732 | } |
1095 | } |
733 | |
1096 | |
|
|
1097 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
1098 | |
734 | unshift @ISA, $MODEL; |
1099 | unshift @ISA, $MODEL; |
735 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
1100 | |
|
|
1101 | require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; |
|
|
1102 | |
|
|
1103 | (shift @post_detect)->() while @post_detect; |
736 | } |
1104 | } |
737 | |
1105 | |
738 | $MODEL |
1106 | $MODEL |
739 | } |
1107 | } |
740 | |
1108 | |
… | |
… | |
748 | |
1116 | |
749 | my $class = shift; |
1117 | my $class = shift; |
750 | $class->$func (@_); |
1118 | $class->$func (@_); |
751 | } |
1119 | } |
752 | |
1120 | |
|
|
1121 | # utility function to dup a filehandle. this is used by many backends |
|
|
1122 | # to support binding more than one watcher per filehandle (they usually |
|
|
1123 | # allow only one watcher per fd, so we dup it to get a different one). |
|
|
1124 | sub _dupfh($$;$$) { |
|
|
1125 | my ($poll, $fh, $r, $w) = @_; |
|
|
1126 | |
|
|
1127 | # cygwin requires the fh mode to be matching, unix doesn't |
|
|
1128 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">"); |
|
|
1129 | |
|
|
1130 | open my $fh2, "$mode&", $fh |
|
|
1131 | or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,"; |
|
|
1132 | |
|
|
1133 | # we assume CLOEXEC is already set by perl in all important cases |
|
|
1134 | |
|
|
1135 | ($fh2, $rw) |
|
|
1136 | } |
|
|
1137 | |
753 | package AnyEvent::Base; |
1138 | package AnyEvent::Base; |
754 | |
1139 | |
|
|
1140 | # default implementations for many methods |
|
|
1141 | |
|
|
1142 | BEGIN { |
|
|
1143 | if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { |
|
|
1144 | *_time = \&Time::HiRes::time; |
|
|
1145 | # if (eval "use POSIX (); (POSIX::times())... |
|
|
1146 | } else { |
|
|
1147 | *_time = sub { time }; # epic fail |
|
|
1148 | } |
|
|
1149 | } |
|
|
1150 | |
|
|
1151 | sub time { _time } |
|
|
1152 | sub now { _time } |
|
|
1153 | sub now_update { } |
|
|
1154 | |
755 | # default implementation for ->condvar, ->wait, ->broadcast |
1155 | # default implementation for ->condvar |
756 | |
1156 | |
757 | sub condvar { |
1157 | sub condvar { |
758 | bless \my $flag, "AnyEvent::Base::CondVar" |
1158 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" |
759 | } |
|
|
760 | |
|
|
761 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
762 | ${$_[0]}++; |
|
|
763 | } |
|
|
764 | |
|
|
765 | sub AnyEvent::Base::CondVar::wait { |
|
|
766 | AnyEvent->one_event while !${$_[0]}; |
|
|
767 | } |
1159 | } |
768 | |
1160 | |
769 | # default implementation for ->signal |
1161 | # default implementation for ->signal |
770 | |
1162 | |
771 | our %SIG_CB; |
1163 | our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); |
|
|
1164 | |
|
|
1165 | sub _signal_exec { |
|
|
1166 | sysread $SIGPIPE_R, my $dummy, 4; |
|
|
1167 | |
|
|
1168 | while (%SIG_EV) { |
|
|
1169 | for (keys %SIG_EV) { |
|
|
1170 | delete $SIG_EV{$_}; |
|
|
1171 | $_->() for values %{ $SIG_CB{$_} || {} }; |
|
|
1172 | } |
|
|
1173 | } |
|
|
1174 | } |
772 | |
1175 | |
773 | sub signal { |
1176 | sub signal { |
774 | my (undef, %arg) = @_; |
1177 | my (undef, %arg) = @_; |
775 | |
1178 | |
|
|
1179 | unless ($SIGPIPE_R) { |
|
|
1180 | require Fcntl; |
|
|
1181 | |
|
|
1182 | if (AnyEvent::WIN32) { |
|
|
1183 | require AnyEvent::Util; |
|
|
1184 | |
|
|
1185 | ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); |
|
|
1186 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R; |
|
|
1187 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case |
|
|
1188 | } else { |
|
|
1189 | pipe $SIGPIPE_R, $SIGPIPE_W; |
|
|
1190 | fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; |
|
|
1191 | fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case |
|
|
1192 | |
|
|
1193 | # not strictly required, as $^F is normally 2, but let's make sure... |
|
|
1194 | fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; |
|
|
1195 | fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; |
|
|
1196 | } |
|
|
1197 | |
|
|
1198 | $SIGPIPE_R |
|
|
1199 | or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; |
|
|
1200 | |
|
|
1201 | $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); |
|
|
1202 | } |
|
|
1203 | |
776 | my $signal = uc $arg{signal} |
1204 | my $signal = uc $arg{signal} |
777 | or Carp::croak "required option 'signal' is missing"; |
1205 | or Carp::croak "required option 'signal' is missing"; |
778 | |
1206 | |
779 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
1207 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
780 | $SIG{$signal} ||= sub { |
1208 | $SIG{$signal} ||= sub { |
781 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
1209 | local $!; |
|
|
1210 | syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; |
|
|
1211 | undef $SIG_EV{$signal}; |
782 | }; |
1212 | }; |
783 | |
1213 | |
784 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
1214 | bless [$signal, $arg{cb}], "AnyEvent::Base::signal" |
785 | } |
1215 | } |
786 | |
1216 | |
787 | sub AnyEvent::Base::Signal::DESTROY { |
1217 | sub AnyEvent::Base::signal::DESTROY { |
788 | my ($signal, $cb) = @{$_[0]}; |
1218 | my ($signal, $cb) = @{$_[0]}; |
789 | |
1219 | |
790 | delete $SIG_CB{$signal}{$cb}; |
1220 | delete $SIG_CB{$signal}{$cb}; |
791 | |
1221 | |
|
|
1222 | # delete doesn't work with older perls - they then |
|
|
1223 | # print weird messages, or just unconditionally exit |
|
|
1224 | # instead of getting the default action. |
792 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
1225 | undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; |
793 | } |
1226 | } |
794 | |
1227 | |
795 | # default implementation for ->child |
1228 | # default implementation for ->child |
796 | |
1229 | |
797 | our %PID_CB; |
1230 | our %PID_CB; |
798 | our $CHLD_W; |
1231 | our $CHLD_W; |
799 | our $CHLD_DELAY_W; |
1232 | our $CHLD_DELAY_W; |
800 | our $PID_IDLE; |
|
|
801 | our $WNOHANG; |
1233 | our $WNOHANG; |
802 | |
1234 | |
803 | sub _child_wait { |
1235 | sub _sigchld { |
804 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
1236 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
805 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
1237 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
806 | (values %{ $PID_CB{0} || {} }); |
1238 | (values %{ $PID_CB{0} || {} }); |
807 | } |
1239 | } |
808 | |
|
|
809 | undef $PID_IDLE; |
|
|
810 | } |
|
|
811 | |
|
|
812 | sub _sigchld { |
|
|
813 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
814 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
815 | undef $CHLD_DELAY_W; |
|
|
816 | &_child_wait; |
|
|
817 | }); |
|
|
818 | } |
1240 | } |
819 | |
1241 | |
820 | sub child { |
1242 | sub child { |
821 | my (undef, %arg) = @_; |
1243 | my (undef, %arg) = @_; |
822 | |
1244 | |
823 | defined (my $pid = $arg{pid} + 0) |
1245 | defined (my $pid = $arg{pid} + 0) |
824 | or Carp::croak "required option 'pid' is missing"; |
1246 | or Carp::croak "required option 'pid' is missing"; |
825 | |
1247 | |
826 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1248 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
827 | |
1249 | |
828 | unless ($WNOHANG) { |
|
|
829 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1250 | $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
830 | } |
|
|
831 | |
1251 | |
832 | unless ($CHLD_W) { |
1252 | unless ($CHLD_W) { |
833 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1253 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
834 | # child could be a zombie already, so make at least one round |
1254 | # child could be a zombie already, so make at least one round |
835 | &_sigchld; |
1255 | &_sigchld; |
836 | } |
1256 | } |
837 | |
1257 | |
838 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
1258 | bless [$pid, $arg{cb}], "AnyEvent::Base::child" |
839 | } |
1259 | } |
840 | |
1260 | |
841 | sub AnyEvent::Base::Child::DESTROY { |
1261 | sub AnyEvent::Base::child::DESTROY { |
842 | my ($pid, $cb) = @{$_[0]}; |
1262 | my ($pid, $cb) = @{$_[0]}; |
843 | |
1263 | |
844 | delete $PID_CB{$pid}{$cb}; |
1264 | delete $PID_CB{$pid}{$cb}; |
845 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1265 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
846 | |
1266 | |
847 | undef $CHLD_W unless keys %PID_CB; |
1267 | undef $CHLD_W unless keys %PID_CB; |
848 | } |
1268 | } |
|
|
1269 | |
|
|
1270 | # idle emulation is done by simply using a timer, regardless |
|
|
1271 | # of whether the process is idle or not, and not letting |
|
|
1272 | # the callback use more than 50% of the time. |
|
|
1273 | sub idle { |
|
|
1274 | my (undef, %arg) = @_; |
|
|
1275 | |
|
|
1276 | my ($cb, $w, $rcb) = $arg{cb}; |
|
|
1277 | |
|
|
1278 | $rcb = sub { |
|
|
1279 | if ($cb) { |
|
|
1280 | $w = _time; |
|
|
1281 | &$cb; |
|
|
1282 | $w = _time - $w; |
|
|
1283 | |
|
|
1284 | # never use more then 50% of the time for the idle watcher, |
|
|
1285 | # within some limits |
|
|
1286 | $w = 0.0001 if $w < 0.0001; |
|
|
1287 | $w = 5 if $w > 5; |
|
|
1288 | |
|
|
1289 | $w = AnyEvent->timer (after => $w, cb => $rcb); |
|
|
1290 | } else { |
|
|
1291 | # clean up... |
|
|
1292 | undef $w; |
|
|
1293 | undef $rcb; |
|
|
1294 | } |
|
|
1295 | }; |
|
|
1296 | |
|
|
1297 | $w = AnyEvent->timer (after => 0.05, cb => $rcb); |
|
|
1298 | |
|
|
1299 | bless \\$cb, "AnyEvent::Base::idle" |
|
|
1300 | } |
|
|
1301 | |
|
|
1302 | sub AnyEvent::Base::idle::DESTROY { |
|
|
1303 | undef $${$_[0]}; |
|
|
1304 | } |
|
|
1305 | |
|
|
1306 | package AnyEvent::CondVar; |
|
|
1307 | |
|
|
1308 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
1309 | |
|
|
1310 | package AnyEvent::CondVar::Base; |
|
|
1311 | |
|
|
1312 | use overload |
|
|
1313 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1314 | fallback => 1; |
|
|
1315 | |
|
|
1316 | sub _send { |
|
|
1317 | # nop |
|
|
1318 | } |
|
|
1319 | |
|
|
1320 | sub send { |
|
|
1321 | my $cv = shift; |
|
|
1322 | $cv->{_ae_sent} = [@_]; |
|
|
1323 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
1324 | $cv->_send; |
|
|
1325 | } |
|
|
1326 | |
|
|
1327 | sub croak { |
|
|
1328 | $_[0]{_ae_croak} = $_[1]; |
|
|
1329 | $_[0]->send; |
|
|
1330 | } |
|
|
1331 | |
|
|
1332 | sub ready { |
|
|
1333 | $_[0]{_ae_sent} |
|
|
1334 | } |
|
|
1335 | |
|
|
1336 | sub _wait { |
|
|
1337 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
1338 | } |
|
|
1339 | |
|
|
1340 | sub recv { |
|
|
1341 | $_[0]->_wait; |
|
|
1342 | |
|
|
1343 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
1344 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
1345 | } |
|
|
1346 | |
|
|
1347 | sub cb { |
|
|
1348 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
1349 | $_[0]{_ae_cb} |
|
|
1350 | } |
|
|
1351 | |
|
|
1352 | sub begin { |
|
|
1353 | ++$_[0]{_ae_counter}; |
|
|
1354 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1355 | } |
|
|
1356 | |
|
|
1357 | sub end { |
|
|
1358 | return if --$_[0]{_ae_counter}; |
|
|
1359 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1360 | } |
|
|
1361 | |
|
|
1362 | # undocumented/compatibility with pre-3.4 |
|
|
1363 | *broadcast = \&send; |
|
|
1364 | *wait = \&_wait; |
|
|
1365 | |
|
|
1366 | =head1 ERROR AND EXCEPTION HANDLING |
|
|
1367 | |
|
|
1368 | In general, AnyEvent does not do any error handling - it relies on the |
|
|
1369 | caller to do that if required. The L<AnyEvent::Strict> module (see also |
|
|
1370 | the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict |
|
|
1371 | checking of all AnyEvent methods, however, which is highly useful during |
|
|
1372 | development. |
|
|
1373 | |
|
|
1374 | As for exception handling (i.e. runtime errors and exceptions thrown while |
|
|
1375 | executing a callback), this is not only highly event-loop specific, but |
|
|
1376 | also not in any way wrapped by this module, as this is the job of the main |
|
|
1377 | program. |
|
|
1378 | |
|
|
1379 | The pure perl event loop simply re-throws the exception (usually |
|
|
1380 | within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<< |
|
|
1381 | $Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and |
|
|
1382 | so on. |
|
|
1383 | |
|
|
1384 | =head1 ENVIRONMENT VARIABLES |
|
|
1385 | |
|
|
1386 | The following environment variables are used by this module or its |
|
|
1387 | submodules. |
|
|
1388 | |
|
|
1389 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
1390 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
1391 | enabled. |
|
|
1392 | |
|
|
1393 | =over 4 |
|
|
1394 | |
|
|
1395 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
1396 | |
|
|
1397 | By default, AnyEvent will be completely silent except in fatal |
|
|
1398 | conditions. You can set this environment variable to make AnyEvent more |
|
|
1399 | talkative. |
|
|
1400 | |
|
|
1401 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
1402 | conditions, such as not being able to load the event model specified by |
|
|
1403 | C<PERL_ANYEVENT_MODEL>. |
|
|
1404 | |
|
|
1405 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
1406 | model it chooses. |
|
|
1407 | |
|
|
1408 | =item C<PERL_ANYEVENT_STRICT> |
|
|
1409 | |
|
|
1410 | AnyEvent does not do much argument checking by default, as thorough |
|
|
1411 | argument checking is very costly. Setting this variable to a true value |
|
|
1412 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
|
|
1413 | check the arguments passed to most method calls. If it finds any problems, |
|
|
1414 | it will croak. |
|
|
1415 | |
|
|
1416 | In other words, enables "strict" mode. |
|
|
1417 | |
|
|
1418 | Unlike C<use strict>, it is definitely recommended to keep it off in |
|
|
1419 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
|
|
1420 | developing programs can be very useful, however. |
|
|
1421 | |
|
|
1422 | =item C<PERL_ANYEVENT_MODEL> |
|
|
1423 | |
|
|
1424 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
1425 | auto detection and -probing kicks in. It must be a string consisting |
|
|
1426 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
1427 | and the resulting module name is loaded and if the load was successful, |
|
|
1428 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
1429 | auto detection and -probing. |
|
|
1430 | |
|
|
1431 | This functionality might change in future versions. |
|
|
1432 | |
|
|
1433 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
1434 | could start your program like this: |
|
|
1435 | |
|
|
1436 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1437 | |
|
|
1438 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1439 | |
|
|
1440 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1441 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1442 | of auto probing). |
|
|
1443 | |
|
|
1444 | Must be set to a comma-separated list of protocols or address families, |
|
|
1445 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1446 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1447 | list. |
|
|
1448 | |
|
|
1449 | This variable can effectively be used for denial-of-service attacks |
|
|
1450 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1451 | small, as the program has to handle conenction and other failures anyways. |
|
|
1452 | |
|
|
1453 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1454 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1455 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1456 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1457 | IPv6, but prefer IPv6 over IPv4. |
|
|
1458 | |
|
|
1459 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1460 | |
|
|
1461 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1462 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1463 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1464 | default. |
|
|
1465 | |
|
|
1466 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1467 | EDNS0 in its DNS requests. |
|
|
1468 | |
|
|
1469 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1470 | |
|
|
1471 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1472 | will create in parallel. |
|
|
1473 | |
|
|
1474 | =item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS> |
|
|
1475 | |
|
|
1476 | The default value for the C<max_outstanding> parameter for the default DNS |
|
|
1477 | resolver - this is the maximum number of parallel DNS requests that are |
|
|
1478 | sent to the DNS server. |
|
|
1479 | |
|
|
1480 | =item C<PERL_ANYEVENT_RESOLV_CONF> |
|
|
1481 | |
|
|
1482 | The file to use instead of F</etc/resolv.conf> (or OS-specific |
|
|
1483 | configuration) in the default resolver. When set to the empty string, no |
|
|
1484 | default config will be used. |
|
|
1485 | |
|
|
1486 | =item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. |
|
|
1487 | |
|
|
1488 | When neither C<ca_file> nor C<ca_path> was specified during |
|
|
1489 | L<AnyEvent::TLS> context creation, and either of these environment |
|
|
1490 | variables exist, they will be used to specify CA certificate locations |
|
|
1491 | instead of a system-dependent default. |
|
|
1492 | |
|
|
1493 | =back |
849 | |
1494 | |
850 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1495 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
851 | |
1496 | |
852 | This is an advanced topic that you do not normally need to use AnyEvent in |
1497 | This is an advanced topic that you do not normally need to use AnyEvent in |
853 | a module. This section is only of use to event loop authors who want to |
1498 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
887 | |
1532 | |
888 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
1533 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
889 | condition variables: code blocking while waiting for a condition will |
1534 | condition variables: code blocking while waiting for a condition will |
890 | C<die>. This still works with most modules/usages, and blocking calls must |
1535 | C<die>. This still works with most modules/usages, and blocking calls must |
891 | not be done in an interactive application, so it makes sense. |
1536 | not be done in an interactive application, so it makes sense. |
892 | |
|
|
893 | =head1 ENVIRONMENT VARIABLES |
|
|
894 | |
|
|
895 | The following environment variables are used by this module: |
|
|
896 | |
|
|
897 | =over 4 |
|
|
898 | |
|
|
899 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
900 | |
|
|
901 | By default, AnyEvent will be completely silent except in fatal |
|
|
902 | conditions. You can set this environment variable to make AnyEvent more |
|
|
903 | talkative. |
|
|
904 | |
|
|
905 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
906 | conditions, such as not being able to load the event model specified by |
|
|
907 | C<PERL_ANYEVENT_MODEL>. |
|
|
908 | |
|
|
909 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
910 | model it chooses. |
|
|
911 | |
|
|
912 | =item C<PERL_ANYEVENT_MODEL> |
|
|
913 | |
|
|
914 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
915 | autodetection and -probing kicks in. It must be a string consisting |
|
|
916 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
917 | and the resulting module name is loaded and if the load was successful, |
|
|
918 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
919 | autodetection and -probing. |
|
|
920 | |
|
|
921 | This functionality might change in future versions. |
|
|
922 | |
|
|
923 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
924 | could start your program like this: |
|
|
925 | |
|
|
926 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
927 | |
|
|
928 | =back |
|
|
929 | |
1537 | |
930 | =head1 EXAMPLE PROGRAM |
1538 | =head1 EXAMPLE PROGRAM |
931 | |
1539 | |
932 | The following program uses an I/O watcher to read data from STDIN, a timer |
1540 | The following program uses an I/O watcher to read data from STDIN, a timer |
933 | to display a message once per second, and a condition variable to quit the |
1541 | to display a message once per second, and a condition variable to quit the |
… | |
… | |
942 | poll => 'r', |
1550 | poll => 'r', |
943 | cb => sub { |
1551 | cb => sub { |
944 | warn "io event <$_[0]>\n"; # will always output <r> |
1552 | warn "io event <$_[0]>\n"; # will always output <r> |
945 | chomp (my $input = <STDIN>); # read a line |
1553 | chomp (my $input = <STDIN>); # read a line |
946 | warn "read: $input\n"; # output what has been read |
1554 | warn "read: $input\n"; # output what has been read |
947 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1555 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
948 | }, |
1556 | }, |
949 | ); |
1557 | ); |
950 | |
1558 | |
951 | my $time_watcher; # can only be used once |
1559 | my $time_watcher; # can only be used once |
952 | |
1560 | |
… | |
… | |
957 | }); |
1565 | }); |
958 | } |
1566 | } |
959 | |
1567 | |
960 | new_timer; # create first timer |
1568 | new_timer; # create first timer |
961 | |
1569 | |
962 | $cv->wait; # wait until user enters /^q/i |
1570 | $cv->recv; # wait until user enters /^q/i |
963 | |
1571 | |
964 | =head1 REAL-WORLD EXAMPLE |
1572 | =head1 REAL-WORLD EXAMPLE |
965 | |
1573 | |
966 | Consider the L<Net::FCP> module. It features (among others) the following |
1574 | Consider the L<Net::FCP> module. It features (among others) the following |
967 | API calls, which are to freenet what HTTP GET requests are to http: |
1575 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
1017 | syswrite $txn->{fh}, $txn->{request} |
1625 | syswrite $txn->{fh}, $txn->{request} |
1018 | or die "connection or write error"; |
1626 | or die "connection or write error"; |
1019 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1627 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1020 | |
1628 | |
1021 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1629 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1022 | result and signals any possible waiters that the request ahs finished: |
1630 | result and signals any possible waiters that the request has finished: |
1023 | |
1631 | |
1024 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1632 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1025 | |
1633 | |
1026 | if (end-of-file or data complete) { |
1634 | if (end-of-file or data complete) { |
1027 | $txn->{result} = $txn->{buf}; |
1635 | $txn->{result} = $txn->{buf}; |
1028 | $txn->{finished}->broadcast; |
1636 | $txn->{finished}->send; |
1029 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1637 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1030 | } |
1638 | } |
1031 | |
1639 | |
1032 | The C<result> method, finally, just waits for the finished signal (if the |
1640 | The C<result> method, finally, just waits for the finished signal (if the |
1033 | request was already finished, it doesn't wait, of course, and returns the |
1641 | request was already finished, it doesn't wait, of course, and returns the |
1034 | data: |
1642 | data: |
1035 | |
1643 | |
1036 | $txn->{finished}->wait; |
1644 | $txn->{finished}->recv; |
1037 | return $txn->{result}; |
1645 | return $txn->{result}; |
1038 | |
1646 | |
1039 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1647 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1040 | that occured during request processing. The C<result> method detects |
1648 | that occurred during request processing. The C<result> method detects |
1041 | whether an exception as thrown (it is stored inside the $txn object) |
1649 | whether an exception as thrown (it is stored inside the $txn object) |
1042 | and just throws the exception, which means connection errors and other |
1650 | and just throws the exception, which means connection errors and other |
1043 | problems get reported tot he code that tries to use the result, not in a |
1651 | problems get reported tot he code that tries to use the result, not in a |
1044 | random callback. |
1652 | random callback. |
1045 | |
1653 | |
… | |
… | |
1076 | |
1684 | |
1077 | my $quit = AnyEvent->condvar; |
1685 | my $quit = AnyEvent->condvar; |
1078 | |
1686 | |
1079 | $fcp->txn_client_get ($url)->cb (sub { |
1687 | $fcp->txn_client_get ($url)->cb (sub { |
1080 | ... |
1688 | ... |
1081 | $quit->broadcast; |
1689 | $quit->send; |
1082 | }); |
1690 | }); |
1083 | |
1691 | |
1084 | $quit->wait; |
1692 | $quit->recv; |
1085 | |
1693 | |
1086 | |
1694 | |
1087 | =head1 BENCHMARKS |
1695 | =head1 BENCHMARKS |
1088 | |
1696 | |
1089 | To give you an idea of the performance and overheads that AnyEvent adds |
1697 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
1091 | of various event loops I prepared some benchmarks. |
1699 | of various event loops I prepared some benchmarks. |
1092 | |
1700 | |
1093 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1701 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1094 | |
1702 | |
1095 | Here is a benchmark of various supported event models used natively and |
1703 | Here is a benchmark of various supported event models used natively and |
1096 | through anyevent. The benchmark creates a lot of timers (with a zero |
1704 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
1097 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1705 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1098 | which it is), lets them fire exactly once and destroys them again. |
1706 | which it is), lets them fire exactly once and destroys them again. |
1099 | |
1707 | |
1100 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1708 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1101 | distribution. |
1709 | distribution. |
… | |
… | |
1118 | all watchers, to avoid adding memory overhead. That means closure creation |
1726 | all watchers, to avoid adding memory overhead. That means closure creation |
1119 | and memory usage is not included in the figures. |
1727 | and memory usage is not included in the figures. |
1120 | |
1728 | |
1121 | I<invoke> is the time, in microseconds, used to invoke a simple |
1729 | I<invoke> is the time, in microseconds, used to invoke a simple |
1122 | callback. The callback simply counts down a Perl variable and after it was |
1730 | callback. The callback simply counts down a Perl variable and after it was |
1123 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1731 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
1124 | signal the end of this phase. |
1732 | signal the end of this phase. |
1125 | |
1733 | |
1126 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1734 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1127 | watcher. |
1735 | watcher. |
1128 | |
1736 | |
1129 | =head3 Results |
1737 | =head3 Results |
1130 | |
1738 | |
1131 | name watchers bytes create invoke destroy comment |
1739 | name watchers bytes create invoke destroy comment |
1132 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
1740 | EV/EV 400000 224 0.47 0.35 0.27 EV native interface |
1133 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
1741 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
1134 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
1742 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
1135 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
1743 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
1136 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
1744 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
1137 | Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers |
1745 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
|
|
1746 | IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll |
|
|
1747 | IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll |
1138 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
1748 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
1139 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
1749 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
1140 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
1750 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
1141 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
1751 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
1142 | |
1752 | |
1143 | =head3 Discussion |
1753 | =head3 Discussion |
1144 | |
1754 | |
1145 | The benchmark does I<not> measure scalability of the event loop very |
1755 | The benchmark does I<not> measure scalability of the event loop very |
1146 | well. For example, a select-based event loop (such as the pure perl one) |
1756 | well. For example, a select-based event loop (such as the pure perl one) |
… | |
… | |
1171 | performance becomes really bad with lots of file descriptors (and few of |
1781 | performance becomes really bad with lots of file descriptors (and few of |
1172 | them active), of course, but this was not subject of this benchmark. |
1782 | them active), of course, but this was not subject of this benchmark. |
1173 | |
1783 | |
1174 | The C<Event> module has a relatively high setup and callback invocation |
1784 | The C<Event> module has a relatively high setup and callback invocation |
1175 | cost, but overall scores in on the third place. |
1785 | cost, but overall scores in on the third place. |
|
|
1786 | |
|
|
1787 | C<IO::Async> performs admirably well, about on par with C<Event>, even |
|
|
1788 | when using its pure perl backend. |
1176 | |
1789 | |
1177 | C<Glib>'s memory usage is quite a bit higher, but it features a |
1790 | C<Glib>'s memory usage is quite a bit higher, but it features a |
1178 | faster callback invocation and overall ends up in the same class as |
1791 | faster callback invocation and overall ends up in the same class as |
1179 | C<Event>. However, Glib scales extremely badly, doubling the number of |
1792 | C<Event>. However, Glib scales extremely badly, doubling the number of |
1180 | watchers increases the processing time by more than a factor of four, |
1793 | watchers increases the processing time by more than a factor of four, |
… | |
… | |
1224 | |
1837 | |
1225 | =back |
1838 | =back |
1226 | |
1839 | |
1227 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1840 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1228 | |
1841 | |
1229 | This benchmark atcually benchmarks the event loop itself. It works by |
1842 | This benchmark actually benchmarks the event loop itself. It works by |
1230 | creating a number of "servers": each server consists of a socketpair, a |
1843 | creating a number of "servers": each server consists of a socket pair, a |
1231 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1844 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1232 | watcher waiting for input on one side of the socket. Each time the socket |
1845 | watcher waiting for input on one side of the socket. Each time the socket |
1233 | watcher reads a byte it will write that byte to a random other "server". |
1846 | watcher reads a byte it will write that byte to a random other "server". |
1234 | |
1847 | |
1235 | The effect is that there will be a lot of I/O watchers, only part of which |
1848 | The effect is that there will be a lot of I/O watchers, only part of which |
1236 | are active at any one point (so there is a constant number of active |
1849 | are active at any one point (so there is a constant number of active |
1237 | fds for each loop iterstaion, but which fds these are is random). The |
1850 | fds for each loop iteration, but which fds these are is random). The |
1238 | timeout is reset each time something is read because that reflects how |
1851 | timeout is reset each time something is read because that reflects how |
1239 | most timeouts work (and puts extra pressure on the event loops). |
1852 | most timeouts work (and puts extra pressure on the event loops). |
1240 | |
1853 | |
1241 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1854 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1242 | (1%) are active. This mirrors the activity of large servers with many |
1855 | (1%) are active. This mirrors the activity of large servers with many |
1243 | connections, most of which are idle at any one point in time. |
1856 | connections, most of which are idle at any one point in time. |
1244 | |
1857 | |
1245 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1858 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1246 | distribution. |
1859 | distribution. |
… | |
… | |
1248 | =head3 Explanation of the columns |
1861 | =head3 Explanation of the columns |
1249 | |
1862 | |
1250 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1863 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1251 | each server has a read and write socket end). |
1864 | each server has a read and write socket end). |
1252 | |
1865 | |
1253 | I<create> is the time it takes to create a socketpair (which is |
1866 | I<create> is the time it takes to create a socket pair (which is |
1254 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1867 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1255 | |
1868 | |
1256 | I<request>, the most important value, is the time it takes to handle a |
1869 | I<request>, the most important value, is the time it takes to handle a |
1257 | single "request", that is, reading the token from the pipe and forwarding |
1870 | single "request", that is, reading the token from the pipe and forwarding |
1258 | it to another server. This includes deleting the old timeout and creating |
1871 | it to another server. This includes deleting the old timeout and creating |
1259 | a new one that moves the timeout into the future. |
1872 | a new one that moves the timeout into the future. |
1260 | |
1873 | |
1261 | =head3 Results |
1874 | =head3 Results |
1262 | |
1875 | |
1263 | name sockets create request |
1876 | name sockets create request |
1264 | EV 20000 69.01 11.16 |
1877 | EV 20000 69.01 11.16 |
1265 | Perl 20000 73.32 35.87 |
1878 | Perl 20000 73.32 35.87 |
|
|
1879 | IOAsync 20000 157.00 98.14 epoll |
|
|
1880 | IOAsync 20000 159.31 616.06 poll |
1266 | Event 20000 212.62 257.32 |
1881 | Event 20000 212.62 257.32 |
1267 | Glib 20000 651.16 1896.30 |
1882 | Glib 20000 651.16 1896.30 |
1268 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1883 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1269 | |
1884 | |
1270 | =head3 Discussion |
1885 | =head3 Discussion |
1271 | |
1886 | |
1272 | This benchmark I<does> measure scalability and overall performance of the |
1887 | This benchmark I<does> measure scalability and overall performance of the |
1273 | particular event loop. |
1888 | particular event loop. |
… | |
… | |
1275 | EV is again fastest. Since it is using epoll on my system, the setup time |
1890 | EV is again fastest. Since it is using epoll on my system, the setup time |
1276 | is relatively high, though. |
1891 | is relatively high, though. |
1277 | |
1892 | |
1278 | Perl surprisingly comes second. It is much faster than the C-based event |
1893 | Perl surprisingly comes second. It is much faster than the C-based event |
1279 | loops Event and Glib. |
1894 | loops Event and Glib. |
|
|
1895 | |
|
|
1896 | IO::Async performs very well when using its epoll backend, and still quite |
|
|
1897 | good compared to Glib when using its pure perl backend. |
1280 | |
1898 | |
1281 | Event suffers from high setup time as well (look at its code and you will |
1899 | Event suffers from high setup time as well (look at its code and you will |
1282 | understand why). Callback invocation also has a high overhead compared to |
1900 | understand why). Callback invocation also has a high overhead compared to |
1283 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
1901 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
1284 | uses select or poll in basically all documented configurations. |
1902 | uses select or poll in basically all documented configurations. |
… | |
… | |
1331 | speed most when you have lots of watchers, not when you only have a few of |
1949 | speed most when you have lots of watchers, not when you only have a few of |
1332 | them). |
1950 | them). |
1333 | |
1951 | |
1334 | EV is again fastest. |
1952 | EV is again fastest. |
1335 | |
1953 | |
1336 | Perl again comes second. It is noticably faster than the C-based event |
1954 | Perl again comes second. It is noticeably faster than the C-based event |
1337 | loops Event and Glib, although the difference is too small to really |
1955 | loops Event and Glib, although the difference is too small to really |
1338 | matter. |
1956 | matter. |
1339 | |
1957 | |
1340 | POE also performs much better in this case, but is is still far behind the |
1958 | POE also performs much better in this case, but is is still far behind the |
1341 | others. |
1959 | others. |
… | |
… | |
1347 | =item * C-based event loops perform very well with small number of |
1965 | =item * C-based event loops perform very well with small number of |
1348 | watchers, as the management overhead dominates. |
1966 | watchers, as the management overhead dominates. |
1349 | |
1967 | |
1350 | =back |
1968 | =back |
1351 | |
1969 | |
|
|
1970 | =head2 THE IO::Lambda BENCHMARK |
|
|
1971 | |
|
|
1972 | Recently I was told about the benchmark in the IO::Lambda manpage, which |
|
|
1973 | could be misinterpreted to make AnyEvent look bad. In fact, the benchmark |
|
|
1974 | simply compares IO::Lambda with POE, and IO::Lambda looks better (which |
|
|
1975 | shouldn't come as a surprise to anybody). As such, the benchmark is |
|
|
1976 | fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't |
|
|
1977 | very optimal. But how would AnyEvent compare when used without the extra |
|
|
1978 | baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. |
|
|
1979 | |
|
|
1980 | The benchmark itself creates an echo-server, and then, for 500 times, |
|
|
1981 | connects to the echo server, sends a line, waits for the reply, and then |
|
|
1982 | creates the next connection. This is a rather bad benchmark, as it doesn't |
|
|
1983 | test the efficiency of the framework or much non-blocking I/O, but it is a |
|
|
1984 | benchmark nevertheless. |
|
|
1985 | |
|
|
1986 | name runtime |
|
|
1987 | Lambda/select 0.330 sec |
|
|
1988 | + optimized 0.122 sec |
|
|
1989 | Lambda/AnyEvent 0.327 sec |
|
|
1990 | + optimized 0.138 sec |
|
|
1991 | Raw sockets/select 0.077 sec |
|
|
1992 | POE/select, components 0.662 sec |
|
|
1993 | POE/select, raw sockets 0.226 sec |
|
|
1994 | POE/select, optimized 0.404 sec |
|
|
1995 | |
|
|
1996 | AnyEvent/select/nb 0.085 sec |
|
|
1997 | AnyEvent/EV/nb 0.068 sec |
|
|
1998 | +state machine 0.134 sec |
|
|
1999 | |
|
|
2000 | The benchmark is also a bit unfair (my fault): the IO::Lambda/POE |
|
|
2001 | benchmarks actually make blocking connects and use 100% blocking I/O, |
|
|
2002 | defeating the purpose of an event-based solution. All of the newly |
|
|
2003 | written AnyEvent benchmarks use 100% non-blocking connects (using |
|
|
2004 | AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS |
|
|
2005 | resolver), so AnyEvent is at a disadvantage here, as non-blocking connects |
|
|
2006 | generally require a lot more bookkeeping and event handling than blocking |
|
|
2007 | connects (which involve a single syscall only). |
|
|
2008 | |
|
|
2009 | The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which |
|
|
2010 | offers similar expressive power as POE and IO::Lambda, using conventional |
|
|
2011 | Perl syntax. This means that both the echo server and the client are 100% |
|
|
2012 | non-blocking, further placing it at a disadvantage. |
|
|
2013 | |
|
|
2014 | As you can see, the AnyEvent + EV combination even beats the |
|
|
2015 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
|
|
2016 | backend easily beats IO::Lambda and POE. |
|
|
2017 | |
|
|
2018 | And even the 100% non-blocking version written using the high-level (and |
|
|
2019 | slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a |
|
|
2020 | large margin, even though it does all of DNS, tcp-connect and socket I/O |
|
|
2021 | in a non-blocking way. |
|
|
2022 | |
|
|
2023 | The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and |
|
|
2024 | F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are |
|
|
2025 | part of the IO::lambda distribution and were used without any changes. |
|
|
2026 | |
|
|
2027 | |
|
|
2028 | =head1 SIGNALS |
|
|
2029 | |
|
|
2030 | AnyEvent currently installs handlers for these signals: |
|
|
2031 | |
|
|
2032 | =over 4 |
|
|
2033 | |
|
|
2034 | =item SIGCHLD |
|
|
2035 | |
|
|
2036 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
|
|
2037 | emulation for event loops that do not support them natively. Also, some |
|
|
2038 | event loops install a similar handler. |
|
|
2039 | |
|
|
2040 | If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will |
|
|
2041 | reset it to default, to avoid losing child exit statuses. |
|
|
2042 | |
|
|
2043 | =item SIGPIPE |
|
|
2044 | |
|
|
2045 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
|
|
2046 | when AnyEvent gets loaded. |
|
|
2047 | |
|
|
2048 | The rationale for this is that AnyEvent users usually do not really depend |
|
|
2049 | on SIGPIPE delivery (which is purely an optimisation for shell use, or |
|
|
2050 | badly-written programs), but C<SIGPIPE> can cause spurious and rare |
|
|
2051 | program exits as a lot of people do not expect C<SIGPIPE> when writing to |
|
|
2052 | some random socket. |
|
|
2053 | |
|
|
2054 | The rationale for installing a no-op handler as opposed to ignoring it is |
|
|
2055 | that this way, the handler will be restored to defaults on exec. |
|
|
2056 | |
|
|
2057 | Feel free to install your own handler, or reset it to defaults. |
|
|
2058 | |
|
|
2059 | =back |
|
|
2060 | |
|
|
2061 | =cut |
|
|
2062 | |
|
|
2063 | undef $SIG{CHLD} |
|
|
2064 | if $SIG{CHLD} eq 'IGNORE'; |
|
|
2065 | |
|
|
2066 | $SIG{PIPE} = sub { } |
|
|
2067 | unless defined $SIG{PIPE}; |
1352 | |
2068 | |
1353 | =head1 FORK |
2069 | =head1 FORK |
1354 | |
2070 | |
1355 | Most event libraries are not fork-safe. The ones who are usually are |
2071 | Most event libraries are not fork-safe. The ones who are usually are |
1356 | because they rely on inefficient but fork-safe C<select> or C<poll> |
2072 | because they rely on inefficient but fork-safe C<select> or C<poll> |
… | |
… | |
1370 | specified in the variable. |
2086 | specified in the variable. |
1371 | |
2087 | |
1372 | You can make AnyEvent completely ignore this variable by deleting it |
2088 | You can make AnyEvent completely ignore this variable by deleting it |
1373 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
2089 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1374 | |
2090 | |
1375 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
2091 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1376 | |
2092 | |
1377 | use AnyEvent; |
2093 | use AnyEvent; |
|
|
2094 | |
|
|
2095 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
2096 | be used to probe what backend is used and gain other information (which is |
|
|
2097 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
|
|
2098 | $ENV{PERL_ANYEVENT_STRICT}. |
|
|
2099 | |
|
|
2100 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
2101 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
2102 | enabled. |
|
|
2103 | |
|
|
2104 | |
|
|
2105 | =head1 BUGS |
|
|
2106 | |
|
|
2107 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
|
|
2108 | to work around. If you suffer from memleaks, first upgrade to Perl 5.10 |
|
|
2109 | and check wether the leaks still show up. (Perl 5.10.0 has other annoying |
|
|
2110 | memleaks, such as leaking on C<map> and C<grep> but it is usually not as |
|
|
2111 | pronounced). |
1378 | |
2112 | |
1379 | |
2113 | |
1380 | =head1 SEE ALSO |
2114 | =head1 SEE ALSO |
1381 | |
2115 | |
1382 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
2116 | Utility functions: L<AnyEvent::Util>. |
1383 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
2117 | |
|
|
2118 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1384 | L<Event::Lib>, L<Qt>, L<POE>. |
2119 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1385 | |
2120 | |
1386 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
2121 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1387 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
2122 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1388 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
2123 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1389 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
2124 | L<AnyEvent::Impl::POE>. |
1390 | |
2125 | |
|
|
2126 | Non-blocking file handles, sockets, TCP clients and |
|
|
2127 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
2128 | |
|
|
2129 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
2130 | |
|
|
2131 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
2132 | |
1391 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
2133 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1392 | |
2134 | |
1393 | |
2135 | |
1394 | =head1 AUTHOR |
2136 | =head1 AUTHOR |
1395 | |
2137 | |
1396 | Marc Lehmann <schmorp@schmorp.de> |
2138 | Marc Lehmann <schmorp@schmorp.de> |
1397 | http://home.schmorp.de/ |
2139 | http://home.schmorp.de/ |
1398 | |
2140 | |
1399 | =cut |
2141 | =cut |
1400 | |
2142 | |
1401 | 1 |
2143 | 1 |
1402 | |
2144 | |