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, POE - various supported event loops |
6 | |
6 | |
7 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
8 | |
8 | |
9 | use AnyEvent; |
9 | use AnyEvent; |
10 | |
10 | |
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15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
16 | ... |
16 | ... |
17 | }); |
17 | }); |
18 | |
18 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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20 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
22 | |
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23 | =head1 INTRODUCTION/TUTORIAL |
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24 | |
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25 | This manpage is mainly a reference manual. If you are interested |
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26 | in a tutorial or some gentle introduction, have a look at the |
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27 | L<AnyEvent::Intro> manpage. |
22 | |
28 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
29 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
30 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
31 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
32 | nowadays. So what is different about AnyEvent? |
27 | |
33 | |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
34 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
29 | policy> and AnyEvent is I<small and efficient>. |
35 | policy> and AnyEvent is I<small and efficient>. |
30 | |
36 | |
31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
37 | 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 |
38 | 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, |
39 | 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, |
40 | 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 |
41 | only one event loop can be active at the same time in a process. AnyEvent |
36 | helps hiding the differences between those event loops. |
42 | cannot change this, but it can hide the differences between those event |
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43 | loops. |
37 | |
44 | |
38 | The goal of AnyEvent is to offer module authors the ability to do event |
45 | 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 |
46 | programming (waiting for I/O or timer events) without subscribing to a |
40 | religion, a way of living, and most importantly: without forcing your |
47 | 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 |
48 | module users into the same thing by forcing them to use the same event |
42 | model you use. |
49 | model you use. |
43 | |
50 | |
44 | For modules like POE or IO::Async (which is a total misnomer as it is |
51 | 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 |
52 | 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 |
53 | 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 |
54 | 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 |
55 | 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. |
56 | module are I<also> forced to use the same event loop you use. |
50 | |
57 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
58 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
59 | 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 |
60 | 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, |
61 | 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 |
62 | 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 |
63 | 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 |
64 | 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). |
65 | to AnyEvent, too, so it is future-proof). |
59 | |
66 | |
60 | In addition to being free of having to use I<the one and only true event |
67 | 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 |
68 | 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 |
69 | 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 |
70 | 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 |
71 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
72 | technically possible. |
66 | |
73 | |
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74 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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75 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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76 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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77 | such as Windows) and lots of real-world knowledge and workarounds for |
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78 | platform bugs and differences. |
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79 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
80 | 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 |
81 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
82 | model, you should I<not> use this module. |
70 | |
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71 | |
83 | |
72 | =head1 DESCRIPTION |
84 | =head1 DESCRIPTION |
73 | |
85 | |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
86 | L<AnyEvent> provides an identical interface to multiple event loops. This |
75 | allows module authors to utilise an event loop without forcing module |
87 | allows module authors to utilise an event loop without forcing module |
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79 | The interface itself is vaguely similar, but not identical to the L<Event> |
91 | The interface itself is vaguely similar, but not identical to the L<Event> |
80 | module. |
92 | module. |
81 | |
93 | |
82 | During the first call of any watcher-creation method, the module tries |
94 | During the first call of any watcher-creation method, the module tries |
83 | to detect the currently loaded event loop by probing whether one of the |
95 | to detect the currently loaded event loop by probing whether one of the |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
96 | following modules is already loaded: L<EV>, |
85 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
97 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
86 | L<POE>. The first one found is used. If none are found, the module tries |
98 | L<POE>. The first one found is used. If none are found, the module tries |
87 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
99 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
88 | adaptor should always succeed) in the order given. The first one that can |
100 | adaptor should always succeed) in the order given. The first one that can |
89 | be successfully loaded will be used. If, after this, still none could be |
101 | be successfully loaded will be used. If, after this, still none could be |
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103 | starts using it, all bets are off. Maybe you should tell their authors to |
115 | starts using it, all bets are off. Maybe you should tell their authors to |
104 | use AnyEvent so their modules work together with others seamlessly... |
116 | use AnyEvent so their modules work together with others seamlessly... |
105 | |
117 | |
106 | The pure-perl implementation of AnyEvent is called |
118 | The pure-perl implementation of AnyEvent is called |
107 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
119 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
108 | explicitly. |
120 | explicitly and enjoy the high availability of that event loop :) |
109 | |
121 | |
110 | =head1 WATCHERS |
122 | =head1 WATCHERS |
111 | |
123 | |
112 | AnyEvent has the central concept of a I<watcher>, which is an object that |
124 | AnyEvent has the central concept of a I<watcher>, which is an object that |
113 | stores relevant data for each kind of event you are waiting for, such as |
125 | stores relevant data for each kind of event you are waiting for, such as |
114 | the callback to call, the filehandle to watch, etc. |
126 | the callback to call, the file handle to watch, etc. |
115 | |
127 | |
116 | These watchers are normal Perl objects with normal Perl lifetime. After |
128 | These watchers are normal Perl objects with normal Perl lifetime. After |
117 | creating a watcher it will immediately "watch" for events and invoke the |
129 | creating a watcher it will immediately "watch" for events and invoke the |
118 | callback when the event occurs (of course, only when the event model |
130 | callback when the event occurs (of course, only when the event model |
119 | is in control). |
131 | is in control). |
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127 | Many watchers either are used with "recursion" (repeating timers for |
139 | Many watchers either are used with "recursion" (repeating timers for |
128 | example), or need to refer to their watcher object in other ways. |
140 | example), or need to refer to their watcher object in other ways. |
129 | |
141 | |
130 | An any way to achieve that is this pattern: |
142 | An any way to achieve that is this pattern: |
131 | |
143 | |
132 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
144 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
133 | # you can use $w here, for example to undef it |
145 | # you can use $w here, for example to undef it |
134 | undef $w; |
146 | undef $w; |
135 | }); |
147 | }); |
136 | |
148 | |
137 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
149 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
138 | my variables are only visible after the statement in which they are |
150 | my variables are only visible after the statement in which they are |
139 | declared. |
151 | declared. |
140 | |
152 | |
141 | =head2 I/O WATCHERS |
153 | =head2 I/O WATCHERS |
142 | |
154 | |
143 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
155 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
144 | with the following mandatory key-value pairs as arguments: |
156 | with the following mandatory key-value pairs as arguments: |
145 | |
157 | |
146 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch |
158 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events |
147 | for events. C<poll> must be a string that is either C<r> or C<w>, |
159 | (AnyEvent might or might not keep a reference to this file handle). C<poll> |
148 | which creates a watcher waiting for "r"eadable or "w"ritable events, |
160 | must be a string that is either C<r> or C<w>, which creates a watcher |
149 | respectively. C<cb> is the callback to invoke each time the file handle |
161 | waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the |
150 | becomes ready. |
162 | callback to invoke each time the file handle becomes ready. |
151 | |
163 | |
152 | Although the callback might get passed parameters, their value and |
164 | Although the callback might get passed parameters, their value and |
153 | presence is undefined and you cannot rely on them. Portable AnyEvent |
165 | presence is undefined and you cannot rely on them. Portable AnyEvent |
154 | callbacks cannot use arguments passed to I/O watcher callbacks. |
166 | callbacks cannot use arguments passed to I/O watcher callbacks. |
155 | |
167 | |
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159 | |
171 | |
160 | Some event loops issue spurious readyness notifications, so you should |
172 | Some event loops issue spurious readyness notifications, so you should |
161 | always use non-blocking calls when reading/writing from/to your file |
173 | always use non-blocking calls when reading/writing from/to your file |
162 | handles. |
174 | handles. |
163 | |
175 | |
164 | Example: |
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165 | |
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166 | # wait for readability of STDIN, then read a line and disable the watcher |
176 | Example: wait for readability of STDIN, then read a line and disable the |
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177 | watcher. |
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178 | |
167 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
179 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
168 | chomp (my $input = <STDIN>); |
180 | chomp (my $input = <STDIN>); |
169 | warn "read: $input\n"; |
181 | warn "read: $input\n"; |
170 | undef $w; |
182 | undef $w; |
171 | }); |
183 | }); |
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181 | |
193 | |
182 | Although the callback might get passed parameters, their value and |
194 | Although the callback might get passed parameters, their value and |
183 | presence is undefined and you cannot rely on them. Portable AnyEvent |
195 | presence is undefined and you cannot rely on them. Portable AnyEvent |
184 | callbacks cannot use arguments passed to time watcher callbacks. |
196 | callbacks cannot use arguments passed to time watcher callbacks. |
185 | |
197 | |
186 | The timer callback will be invoked at most once: if you want a repeating |
198 | The callback will normally be invoked once only. If you specify another |
187 | timer you have to create a new watcher (this is a limitation by both Tk |
199 | parameter, C<interval>, as a strictly positive number (> 0), then the |
188 | and Glib). |
200 | callback will be invoked regularly at that interval (in fractional |
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201 | seconds) after the first invocation. If C<interval> is specified with a |
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202 | false value, then it is treated as if it were missing. |
189 | |
203 | |
190 | Example: |
204 | The callback will be rescheduled before invoking the callback, but no |
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205 | attempt is done to avoid timer drift in most backends, so the interval is |
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206 | only approximate. |
191 | |
207 | |
192 | # fire an event after 7.7 seconds |
208 | Example: fire an event after 7.7 seconds. |
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209 | |
193 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
210 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
194 | warn "timeout\n"; |
211 | warn "timeout\n"; |
195 | }); |
212 | }); |
196 | |
213 | |
197 | # to cancel the timer: |
214 | # to cancel the timer: |
198 | undef $w; |
215 | undef $w; |
199 | |
216 | |
200 | Example 2: |
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201 | |
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202 | # fire an event after 0.5 seconds, then roughly every second |
217 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
203 | my $w; |
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204 | |
218 | |
205 | my $cb = sub { |
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206 | # cancel the old timer while creating a new one |
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207 | $w = AnyEvent->timer (after => 1, cb => $cb); |
219 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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220 | warn "timeout\n"; |
208 | }; |
221 | }; |
209 | |
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210 | # start the "loop" by creating the first watcher |
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211 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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212 | |
222 | |
213 | =head3 TIMING ISSUES |
223 | =head3 TIMING ISSUES |
214 | |
224 | |
215 | There are two ways to handle timers: based on real time (relative, "fire |
225 | There are two ways to handle timers: based on real time (relative, "fire |
216 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
226 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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228 | timers. |
238 | timers. |
229 | |
239 | |
230 | AnyEvent always prefers relative timers, if available, matching the |
240 | AnyEvent always prefers relative timers, if available, matching the |
231 | AnyEvent API. |
241 | AnyEvent API. |
232 | |
242 | |
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243 | AnyEvent has two additional methods that return the "current time": |
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244 | |
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245 | =over 4 |
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246 | |
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247 | =item AnyEvent->time |
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248 | |
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249 | This returns the "current wallclock time" as a fractional number of |
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250 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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251 | return, and the result is guaranteed to be compatible with those). |
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252 | |
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253 | It progresses independently of any event loop processing, i.e. each call |
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254 | will check the system clock, which usually gets updated frequently. |
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255 | |
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256 | =item AnyEvent->now |
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257 | |
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258 | This also returns the "current wallclock time", but unlike C<time>, above, |
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259 | this value might change only once per event loop iteration, depending on |
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260 | the event loop (most return the same time as C<time>, above). This is the |
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261 | time that AnyEvent's timers get scheduled against. |
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262 | |
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263 | I<In almost all cases (in all cases if you don't care), this is the |
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264 | function to call when you want to know the current time.> |
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265 | |
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266 | This function is also often faster then C<< AnyEvent->time >>, and |
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267 | thus the preferred method if you want some timestamp (for example, |
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268 | L<AnyEvent::Handle> uses this to update it's activity timeouts). |
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269 | |
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270 | The rest of this section is only of relevance if you try to be very exact |
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271 | with your timing, you can skip it without bad conscience. |
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272 | |
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273 | For a practical example of when these times differ, consider L<Event::Lib> |
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274 | and L<EV> and the following set-up: |
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275 | |
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276 | The event loop is running and has just invoked one of your callback at |
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277 | time=500 (assume no other callbacks delay processing). In your callback, |
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278 | you wait a second by executing C<sleep 1> (blocking the process for a |
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279 | second) and then (at time=501) you create a relative timer that fires |
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280 | after three seconds. |
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281 | |
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282 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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283 | both return C<501>, because that is the current time, and the timer will |
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284 | be scheduled to fire at time=504 (C<501> + C<3>). |
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285 | |
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286 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
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287 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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288 | last event processing phase started. With L<EV>, your timer gets scheduled |
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289 | to run at time=503 (C<500> + C<3>). |
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290 | |
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291 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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292 | regardless of any delays introduced by event processing. However, most |
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293 | callbacks do not expect large delays in processing, so this causes a |
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294 | higher drift (and a lot more system calls to get the current time). |
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295 | |
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296 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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297 | the same time, regardless of how long event processing actually took. |
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298 | |
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299 | In either case, if you care (and in most cases, you don't), then you |
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300 | can get whatever behaviour you want with any event loop, by taking the |
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301 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
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302 | account. |
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303 | |
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304 | =back |
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305 | |
233 | =head2 SIGNAL WATCHERS |
306 | =head2 SIGNAL WATCHERS |
234 | |
307 | |
235 | You can watch for signals using a signal watcher, C<signal> is the signal |
308 | You can watch for signals using a signal watcher, C<signal> is the signal |
236 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
309 | I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl |
237 | be invoked whenever a signal occurs. |
310 | callback to be invoked whenever a signal occurs. |
238 | |
311 | |
239 | Although the callback might get passed parameters, their value and |
312 | Although the callback might get passed parameters, their value and |
240 | presence is undefined and you cannot rely on them. Portable AnyEvent |
313 | presence is undefined and you cannot rely on them. Portable AnyEvent |
241 | callbacks cannot use arguments passed to signal watcher callbacks. |
314 | callbacks cannot use arguments passed to signal watcher callbacks. |
242 | |
315 | |
243 | Multiple signal occurances can be clumped together into one callback |
316 | Multiple signal occurrences can be clumped together into one callback |
244 | invocation, and callback invocation will be synchronous. synchronous means |
317 | invocation, and callback invocation will be synchronous. Synchronous means |
245 | that it might take a while until the signal gets handled by the process, |
318 | that it might take a while until the signal gets handled by the process, |
246 | but it is guarenteed not to interrupt any other callbacks. |
319 | but it is guaranteed not to interrupt any other callbacks. |
247 | |
320 | |
248 | The main advantage of using these watchers is that you can share a signal |
321 | The main advantage of using these watchers is that you can share a signal |
249 | between multiple watchers. |
322 | between multiple watchers. |
250 | |
323 | |
251 | This watcher might use C<%SIG>, so programs overwriting those signals |
324 | This watcher might use C<%SIG>, so programs overwriting those signals |
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278 | AnyEvent program, you I<have> to create at least one watcher before you |
351 | AnyEvent program, you I<have> to create at least one watcher before you |
279 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
352 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
280 | |
353 | |
281 | Example: fork a process and wait for it |
354 | Example: fork a process and wait for it |
282 | |
355 | |
283 | my $done = AnyEvent->condvar; |
356 | my $done = AnyEvent->condvar; |
284 | |
357 | |
285 | AnyEvent::detect; # force event module to be initialised |
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286 | |
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287 | my $pid = fork or exit 5; |
358 | my $pid = fork or exit 5; |
288 | |
359 | |
289 | my $w = AnyEvent->child ( |
360 | my $w = AnyEvent->child ( |
290 | pid => $pid, |
361 | pid => $pid, |
291 | cb => sub { |
362 | cb => sub { |
292 | my ($pid, $status) = @_; |
363 | my ($pid, $status) = @_; |
293 | warn "pid $pid exited with status $status"; |
364 | warn "pid $pid exited with status $status"; |
294 | $done->broadcast; |
365 | $done->send; |
295 | }, |
366 | }, |
296 | ); |
367 | ); |
297 | |
368 | |
298 | # do something else, then wait for process exit |
369 | # do something else, then wait for process exit |
299 | $done->wait; |
370 | $done->recv; |
300 | |
371 | |
301 | =head2 CONDITION VARIABLES |
372 | =head2 CONDITION VARIABLES |
302 | |
373 | |
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374 | If you are familiar with some event loops you will know that all of them |
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375 | require you to run some blocking "loop", "run" or similar function that |
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376 | will actively watch for new events and call your callbacks. |
|
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377 | |
|
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378 | AnyEvent is different, it expects somebody else to run the event loop and |
|
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379 | will only block when necessary (usually when told by the user). |
|
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380 | |
|
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381 | The instrument to do that is called a "condition variable", so called |
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382 | because they represent a condition that must become true. |
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383 | |
303 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
384 | Condition variables can be created by calling the C<< AnyEvent->condvar |
304 | method without any arguments. |
385 | >> method, usually without arguments. The only argument pair allowed is |
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386 | C<cb>, which specifies a callback to be called when the condition variable |
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387 | becomes true. |
305 | |
388 | |
306 | A condition variable waits for a condition - precisely that the C<< |
389 | After creation, the condition variable is "false" until it becomes "true" |
307 | ->broadcast >> method has been called. |
390 | by calling the C<send> method (or calling the condition variable as if it |
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391 | were a callback, read about the caveats in the description for the C<< |
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392 | ->send >> method). |
308 | |
393 | |
309 | They are very useful to signal that a condition has been fulfilled, for |
394 | Condition variables are similar to callbacks, except that you can |
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395 | optionally wait for them. They can also be called merge points - points |
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396 | in time where multiple outstanding events have been processed. And yet |
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397 | another way to call them is transactions - each condition variable can be |
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398 | used to represent a transaction, which finishes at some point and delivers |
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399 | a result. |
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400 | |
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401 | Condition variables are very useful to signal that something has finished, |
310 | example, if you write a module that does asynchronous http requests, |
402 | for example, if you write a module that does asynchronous http requests, |
311 | then a condition variable would be the ideal candidate to signal the |
403 | then a condition variable would be the ideal candidate to signal the |
312 | availability of results. |
404 | availability of results. The user can either act when the callback is |
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405 | called or can synchronously C<< ->recv >> for the results. |
313 | |
406 | |
314 | You can also use condition variables to block your main program until |
407 | You can also use them to simulate traditional event loops - for example, |
315 | an event occurs - for example, you could C<< ->wait >> in your main |
408 | you can block your main program until an event occurs - for example, you |
316 | program until the user clicks the Quit button in your app, which would C<< |
409 | could C<< ->recv >> in your main program until the user clicks the Quit |
317 | ->broadcast >> the "quit" event. |
410 | button of your app, which would C<< ->send >> the "quit" event. |
318 | |
411 | |
319 | Note that condition variables recurse into the event loop - if you have |
412 | Note that condition variables recurse into the event loop - if you have |
320 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
413 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
321 | lose. Therefore, condition variables are good to export to your caller, but |
414 | lose. Therefore, condition variables are good to export to your caller, but |
322 | you should avoid making a blocking wait yourself, at least in callbacks, |
415 | you should avoid making a blocking wait yourself, at least in callbacks, |
323 | as this asks for trouble. |
416 | as this asks for trouble. |
324 | |
417 | |
325 | This object has two methods: |
418 | Condition variables are represented by hash refs in perl, and the keys |
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419 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
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420 | easy (it is often useful to build your own transaction class on top of |
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421 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
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422 | it's C<new> method in your own C<new> method. |
|
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423 | |
|
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424 | There are two "sides" to a condition variable - the "producer side" which |
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425 | eventually calls C<< -> send >>, and the "consumer side", which waits |
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426 | for the send to occur. |
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427 | |
|
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428 | Example: wait for a timer. |
|
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429 | |
|
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430 | # wait till the result is ready |
|
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431 | my $result_ready = AnyEvent->condvar; |
|
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432 | |
|
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433 | # do something such as adding a timer |
|
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434 | # or socket watcher the calls $result_ready->send |
|
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435 | # when the "result" is ready. |
|
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436 | # in this case, we simply use a timer: |
|
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437 | my $w = AnyEvent->timer ( |
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438 | after => 1, |
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439 | cb => sub { $result_ready->send }, |
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440 | ); |
|
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441 | |
|
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442 | # this "blocks" (while handling events) till the callback |
|
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443 | # calls send |
|
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444 | $result_ready->recv; |
|
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445 | |
|
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446 | Example: wait for a timer, but take advantage of the fact that |
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447 | condition variables are also code references. |
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448 | |
|
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449 | my $done = AnyEvent->condvar; |
|
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450 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
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451 | $done->recv; |
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452 | |
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|
453 | =head3 METHODS FOR PRODUCERS |
|
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454 | |
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455 | These methods should only be used by the producing side, i.e. the |
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456 | code/module that eventually sends the signal. Note that it is also |
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457 | the producer side which creates the condvar in most cases, but it isn't |
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458 | uncommon for the consumer to create it as well. |
326 | |
459 | |
327 | =over 4 |
460 | =over 4 |
328 | |
461 | |
|
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462 | =item $cv->send (...) |
|
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463 | |
|
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464 | Flag the condition as ready - a running C<< ->recv >> and all further |
|
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465 | calls to C<recv> will (eventually) return after this method has been |
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466 | called. If nobody is waiting the send will be remembered. |
|
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467 | |
|
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468 | If a callback has been set on the condition variable, it is called |
|
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469 | immediately from within send. |
|
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470 | |
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471 | Any arguments passed to the C<send> call will be returned by all |
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472 | future C<< ->recv >> calls. |
|
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473 | |
|
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474 | Condition variables are overloaded so one can call them directly |
|
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475 | (as a code reference). Calling them directly is the same as calling |
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476 | C<send>. Note, however, that many C-based event loops do not handle |
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477 | overloading, so as tempting as it may be, passing a condition variable |
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478 | instead of a callback does not work. Both the pure perl and EV loops |
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479 | support overloading, however, as well as all functions that use perl to |
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480 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
|
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481 | example). |
|
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482 | |
|
|
483 | =item $cv->croak ($error) |
|
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484 | |
|
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485 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
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486 | C<Carp::croak> with the given error message/object/scalar. |
|
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487 | |
|
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488 | This can be used to signal any errors to the condition variable |
|
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489 | user/consumer. |
|
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490 | |
|
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491 | =item $cv->begin ([group callback]) |
|
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492 | |
329 | =item $cv->wait |
493 | =item $cv->end |
330 | |
494 | |
331 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
495 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
|
|
496 | |
|
|
497 | These two methods can be used to combine many transactions/events into |
|
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498 | one. For example, a function that pings many hosts in parallel might want |
|
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499 | to use a condition variable for the whole process. |
|
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500 | |
|
|
501 | Every call to C<< ->begin >> will increment a counter, and every call to |
|
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502 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
|
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503 | >>, the (last) callback passed to C<begin> will be executed. That callback |
|
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504 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
|
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505 | callback was set, C<send> will be called without any arguments. |
|
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506 | |
|
|
507 | Let's clarify this with the ping example: |
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508 | |
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509 | my $cv = AnyEvent->condvar; |
|
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510 | |
|
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511 | my %result; |
|
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512 | $cv->begin (sub { $cv->send (\%result) }); |
|
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513 | |
|
|
514 | for my $host (@list_of_hosts) { |
|
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515 | $cv->begin; |
|
|
516 | ping_host_then_call_callback $host, sub { |
|
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517 | $result{$host} = ...; |
|
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518 | $cv->end; |
|
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519 | }; |
|
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520 | } |
|
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521 | |
|
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522 | $cv->end; |
|
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523 | |
|
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524 | This code fragment supposedly pings a number of hosts and calls |
|
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525 | C<send> after results for all then have have been gathered - in any |
|
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526 | order. To achieve this, the code issues a call to C<begin> when it starts |
|
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527 | each ping request and calls C<end> when it has received some result for |
|
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528 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
|
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529 | results arrive is not relevant. |
|
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530 | |
|
|
531 | There is an additional bracketing call to C<begin> and C<end> outside the |
|
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532 | loop, which serves two important purposes: first, it sets the callback |
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533 | to be called once the counter reaches C<0>, and second, it ensures that |
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534 | C<send> is called even when C<no> hosts are being pinged (the loop |
|
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535 | doesn't execute once). |
|
|
536 | |
|
|
537 | This is the general pattern when you "fan out" into multiple subrequests: |
|
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538 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
|
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539 | is called at least once, and then, for each subrequest you start, call |
|
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540 | C<begin> and for each subrequest you finish, call C<end>. |
|
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541 | |
|
|
542 | =back |
|
|
543 | |
|
|
544 | =head3 METHODS FOR CONSUMERS |
|
|
545 | |
|
|
546 | These methods should only be used by the consuming side, i.e. the |
|
|
547 | code awaits the condition. |
|
|
548 | |
|
|
549 | =over 4 |
|
|
550 | |
|
|
551 | =item $cv->recv |
|
|
552 | |
|
|
553 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
332 | called on c<$cv>, while servicing other watchers normally. |
554 | >> methods have been called on c<$cv>, while servicing other watchers |
|
|
555 | normally. |
333 | |
556 | |
334 | You can only wait once on a condition - additional calls will return |
557 | You can only wait once on a condition - additional calls are valid but |
335 | immediately. |
558 | will return immediately. |
|
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559 | |
|
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560 | If an error condition has been set by calling C<< ->croak >>, then this |
|
|
561 | function will call C<croak>. |
|
|
562 | |
|
|
563 | In list context, all parameters passed to C<send> will be returned, |
|
|
564 | in scalar context only the first one will be returned. |
336 | |
565 | |
337 | Not all event models support a blocking wait - some die in that case |
566 | Not all event models support a blocking wait - some die in that case |
338 | (programs might want to do that to stay interactive), so I<if you are |
567 | (programs might want to do that to stay interactive), so I<if you are |
339 | using this from a module, never require a blocking wait>, but let the |
568 | using this from a module, never require a blocking wait>, but let the |
340 | caller decide whether the call will block or not (for example, by coupling |
569 | caller decide whether the call will block or not (for example, by coupling |
341 | condition variables with some kind of request results and supporting |
570 | condition variables with some kind of request results and supporting |
342 | callbacks so the caller knows that getting the result will not block, |
571 | callbacks so the caller knows that getting the result will not block, |
343 | while still suppporting blocking waits if the caller so desires). |
572 | while still supporting blocking waits if the caller so desires). |
344 | |
573 | |
345 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
574 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
346 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
575 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
347 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
576 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
348 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
577 | can supply. |
349 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
350 | from different coroutines, however). |
|
|
351 | |
578 | |
352 | =item $cv->broadcast |
579 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
580 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
581 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
582 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
583 | coroutine (one that doesn't run the event loop). |
353 | |
584 | |
354 | Flag the condition as ready - a running C<< ->wait >> and all further |
585 | You can ensure that C<< -recv >> never blocks by setting a callback and |
355 | calls to C<wait> will (eventually) return after this method has been |
586 | only calling C<< ->recv >> from within that callback (or at a later |
356 | called. If nobody is waiting the broadcast will be remembered.. |
587 | time). This will work even when the event loop does not support blocking |
|
|
588 | waits otherwise. |
|
|
589 | |
|
|
590 | =item $bool = $cv->ready |
|
|
591 | |
|
|
592 | Returns true when the condition is "true", i.e. whether C<send> or |
|
|
593 | C<croak> have been called. |
|
|
594 | |
|
|
595 | =item $cb = $cv->cb ([new callback]) |
|
|
596 | |
|
|
597 | This is a mutator function that returns the callback set and optionally |
|
|
598 | replaces it before doing so. |
|
|
599 | |
|
|
600 | The callback will be called when the condition becomes "true", i.e. when |
|
|
601 | C<send> or C<croak> are called, with the only argument being the condition |
|
|
602 | variable itself. Calling C<recv> inside the callback or at any later time |
|
|
603 | is guaranteed not to block. |
357 | |
604 | |
358 | =back |
605 | =back |
359 | |
|
|
360 | Example: |
|
|
361 | |
|
|
362 | # wait till the result is ready |
|
|
363 | my $result_ready = AnyEvent->condvar; |
|
|
364 | |
|
|
365 | # do something such as adding a timer |
|
|
366 | # or socket watcher the calls $result_ready->broadcast |
|
|
367 | # when the "result" is ready. |
|
|
368 | # in this case, we simply use a timer: |
|
|
369 | my $w = AnyEvent->timer ( |
|
|
370 | after => 1, |
|
|
371 | cb => sub { $result_ready->broadcast }, |
|
|
372 | ); |
|
|
373 | |
|
|
374 | # this "blocks" (while handling events) till the watcher |
|
|
375 | # calls broadcast |
|
|
376 | $result_ready->wait; |
|
|
377 | |
606 | |
378 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
607 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
379 | |
608 | |
380 | =over 4 |
609 | =over 4 |
381 | |
610 | |
… | |
… | |
387 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
616 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
388 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
617 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
389 | |
618 | |
390 | The known classes so far are: |
619 | The known classes so far are: |
391 | |
620 | |
392 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
393 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
394 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
621 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
395 | AnyEvent::Impl::Event based on Event, second best choice. |
622 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
623 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
396 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
624 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
397 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
398 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
625 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
399 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
626 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
400 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
627 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
401 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
628 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
402 | |
629 | |
… | |
… | |
415 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
642 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
416 | if necessary. You should only call this function right before you would |
643 | if necessary. You should only call this function right before you would |
417 | have created an AnyEvent watcher anyway, that is, as late as possible at |
644 | have created an AnyEvent watcher anyway, that is, as late as possible at |
418 | runtime. |
645 | runtime. |
419 | |
646 | |
|
|
647 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
648 | |
|
|
649 | Arranges for the code block to be executed as soon as the event model is |
|
|
650 | autodetected (or immediately if this has already happened). |
|
|
651 | |
|
|
652 | If called in scalar or list context, then it creates and returns an object |
|
|
653 | that automatically removes the callback again when it is destroyed. See |
|
|
654 | L<Coro::BDB> for a case where this is useful. |
|
|
655 | |
|
|
656 | =item @AnyEvent::post_detect |
|
|
657 | |
|
|
658 | If there are any code references in this array (you can C<push> to it |
|
|
659 | before or after loading AnyEvent), then they will called directly after |
|
|
660 | the event loop has been chosen. |
|
|
661 | |
|
|
662 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
663 | if it contains a true value then the event loop has already been detected, |
|
|
664 | and the array will be ignored. |
|
|
665 | |
|
|
666 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
667 | |
420 | =back |
668 | =back |
421 | |
669 | |
422 | =head1 WHAT TO DO IN A MODULE |
670 | =head1 WHAT TO DO IN A MODULE |
423 | |
671 | |
424 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
672 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
427 | Be careful when you create watchers in the module body - AnyEvent will |
675 | Be careful when you create watchers in the module body - AnyEvent will |
428 | decide which event module to use as soon as the first method is called, so |
676 | decide which event module to use as soon as the first method is called, so |
429 | by calling AnyEvent in your module body you force the user of your module |
677 | by calling AnyEvent in your module body you force the user of your module |
430 | to load the event module first. |
678 | to load the event module first. |
431 | |
679 | |
432 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
680 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
433 | the C<< ->broadcast >> method has been called on it already. This is |
681 | the C<< ->send >> method has been called on it already. This is |
434 | because it will stall the whole program, and the whole point of using |
682 | because it will stall the whole program, and the whole point of using |
435 | events is to stay interactive. |
683 | events is to stay interactive. |
436 | |
684 | |
437 | It is fine, however, to call C<< ->wait >> when the user of your module |
685 | It is fine, however, to call C<< ->recv >> when the user of your module |
438 | requests it (i.e. if you create a http request object ad have a method |
686 | requests it (i.e. if you create a http request object ad have a method |
439 | called C<results> that returns the results, it should call C<< ->wait >> |
687 | called C<results> that returns the results, it should call C<< ->recv >> |
440 | freely, as the user of your module knows what she is doing. always). |
688 | freely, as the user of your module knows what she is doing. always). |
441 | |
689 | |
442 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
690 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
443 | |
691 | |
444 | There will always be a single main program - the only place that should |
692 | There will always be a single main program - the only place that should |
… | |
… | |
446 | |
694 | |
447 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
695 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
448 | do anything special (it does not need to be event-based) and let AnyEvent |
696 | do anything special (it does not need to be event-based) and let AnyEvent |
449 | decide which implementation to chose if some module relies on it. |
697 | decide which implementation to chose if some module relies on it. |
450 | |
698 | |
451 | If the main program relies on a specific event model. For example, in |
699 | If the main program relies on a specific event model - for example, in |
452 | Gtk2 programs you have to rely on the Glib module. You should load the |
700 | Gtk2 programs you have to rely on the Glib module - you should load the |
453 | event module before loading AnyEvent or any module that uses it: generally |
701 | event module before loading AnyEvent or any module that uses it: generally |
454 | speaking, you should load it as early as possible. The reason is that |
702 | speaking, you should load it as early as possible. The reason is that |
455 | modules might create watchers when they are loaded, and AnyEvent will |
703 | modules might create watchers when they are loaded, and AnyEvent will |
456 | decide on the event model to use as soon as it creates watchers, and it |
704 | decide on the event model to use as soon as it creates watchers, and it |
457 | might chose the wrong one unless you load the correct one yourself. |
705 | might chose the wrong one unless you load the correct one yourself. |
458 | |
706 | |
459 | You can chose to use a rather inefficient pure-perl implementation by |
707 | You can chose to use a pure-perl implementation by loading the |
460 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
708 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
461 | behaviour everywhere, but letting AnyEvent chose is generally better. |
709 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
710 | |
|
|
711 | =head2 MAINLOOP EMULATION |
|
|
712 | |
|
|
713 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
714 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
715 | |
|
|
716 | In that case, you can use a condition variable like this: |
|
|
717 | |
|
|
718 | AnyEvent->condvar->recv; |
|
|
719 | |
|
|
720 | This has the effect of entering the event loop and looping forever. |
|
|
721 | |
|
|
722 | Note that usually your program has some exit condition, in which case |
|
|
723 | it is better to use the "traditional" approach of storing a condition |
|
|
724 | variable somewhere, waiting for it, and sending it when the program should |
|
|
725 | exit cleanly. |
|
|
726 | |
|
|
727 | |
|
|
728 | =head1 OTHER MODULES |
|
|
729 | |
|
|
730 | The following is a non-exhaustive list of additional modules that use |
|
|
731 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
|
|
732 | in the same program. Some of the modules come with AnyEvent, some are |
|
|
733 | available via CPAN. |
|
|
734 | |
|
|
735 | =over 4 |
|
|
736 | |
|
|
737 | =item L<AnyEvent::Util> |
|
|
738 | |
|
|
739 | Contains various utility functions that replace often-used but blocking |
|
|
740 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
741 | |
|
|
742 | =item L<AnyEvent::Socket> |
|
|
743 | |
|
|
744 | Provides various utility functions for (internet protocol) sockets, |
|
|
745 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
746 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
747 | |
|
|
748 | =item L<AnyEvent::Handle> |
|
|
749 | |
|
|
750 | Provide read and write buffers, manages watchers for reads and writes, |
|
|
751 | supports raw and formatted I/O, I/O queued and fully transparent and |
|
|
752 | non-blocking SSL/TLS. |
|
|
753 | |
|
|
754 | =item L<AnyEvent::DNS> |
|
|
755 | |
|
|
756 | Provides rich asynchronous DNS resolver capabilities. |
|
|
757 | |
|
|
758 | =item L<AnyEvent::HTTP> |
|
|
759 | |
|
|
760 | A simple-to-use HTTP library that is capable of making a lot of concurrent |
|
|
761 | HTTP requests. |
|
|
762 | |
|
|
763 | =item L<AnyEvent::HTTPD> |
|
|
764 | |
|
|
765 | Provides a simple web application server framework. |
|
|
766 | |
|
|
767 | =item L<AnyEvent::FastPing> |
|
|
768 | |
|
|
769 | The fastest ping in the west. |
|
|
770 | |
|
|
771 | =item L<AnyEvent::DBI> |
|
|
772 | |
|
|
773 | Executes L<DBI> requests asynchronously in a proxy process. |
|
|
774 | |
|
|
775 | =item L<AnyEvent::AIO> |
|
|
776 | |
|
|
777 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
778 | programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent |
|
|
779 | together. |
|
|
780 | |
|
|
781 | =item L<AnyEvent::BDB> |
|
|
782 | |
|
|
783 | Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses |
|
|
784 | L<BDB> and AnyEvent together. |
|
|
785 | |
|
|
786 | =item L<AnyEvent::GPSD> |
|
|
787 | |
|
|
788 | A non-blocking interface to gpsd, a daemon delivering GPS information. |
|
|
789 | |
|
|
790 | =item L<AnyEvent::IGS> |
|
|
791 | |
|
|
792 | A non-blocking interface to the Internet Go Server protocol (used by |
|
|
793 | L<App::IGS>). |
|
|
794 | |
|
|
795 | =item L<Net::IRC3> |
|
|
796 | |
|
|
797 | AnyEvent based IRC client module family. |
|
|
798 | |
|
|
799 | =item L<Net::XMPP2> |
|
|
800 | |
|
|
801 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
802 | |
|
|
803 | =item L<Net::FCP> |
|
|
804 | |
|
|
805 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
806 | of AnyEvent. |
|
|
807 | |
|
|
808 | =item L<Event::ExecFlow> |
|
|
809 | |
|
|
810 | High level API for event-based execution flow control. |
|
|
811 | |
|
|
812 | =item L<Coro> |
|
|
813 | |
|
|
814 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
815 | |
|
|
816 | =item L<IO::Lambda> |
|
|
817 | |
|
|
818 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
819 | |
|
|
820 | =back |
462 | |
821 | |
463 | =cut |
822 | =cut |
464 | |
823 | |
465 | package AnyEvent; |
824 | package AnyEvent; |
466 | |
825 | |
467 | no warnings; |
826 | no warnings; |
468 | use strict; |
827 | use strict; |
469 | |
828 | |
470 | use Carp; |
829 | use Carp; |
471 | |
830 | |
472 | our $VERSION = '3.3'; |
831 | our $VERSION = 4.2; |
473 | our $MODEL; |
832 | our $MODEL; |
474 | |
833 | |
475 | our $AUTOLOAD; |
834 | our $AUTOLOAD; |
476 | our @ISA; |
835 | our @ISA; |
477 | |
836 | |
|
|
837 | our @REGISTRY; |
|
|
838 | |
|
|
839 | our $WIN32; |
|
|
840 | |
|
|
841 | BEGIN { |
|
|
842 | my $win32 = ! ! ($^O =~ /mswin32/i); |
|
|
843 | eval "sub WIN32(){ $win32 }"; |
|
|
844 | } |
|
|
845 | |
478 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
846 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
479 | |
847 | |
480 | our @REGISTRY; |
848 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
849 | |
|
|
850 | { |
|
|
851 | my $idx; |
|
|
852 | $PROTOCOL{$_} = ++$idx |
|
|
853 | for reverse split /\s*,\s*/, |
|
|
854 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
855 | } |
481 | |
856 | |
482 | my @models = ( |
857 | my @models = ( |
483 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
484 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
485 | [EV:: => AnyEvent::Impl::EV::], |
858 | [EV:: => AnyEvent::Impl::EV::], |
486 | [Event:: => AnyEvent::Impl::Event::], |
859 | [Event:: => AnyEvent::Impl::Event::], |
487 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
488 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
489 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
490 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
491 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
860 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
492 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
861 | # everything below here will not be autoprobed |
|
|
862 | # as the pureperl backend should work everywhere |
|
|
863 | # and is usually faster |
|
|
864 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
865 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
493 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
866 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
494 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
867 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
495 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
868 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
869 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
870 | [Prima:: => AnyEvent::Impl::POE::], |
496 | ); |
871 | ); |
497 | |
872 | |
498 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
873 | our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); |
|
|
874 | |
|
|
875 | our @post_detect; |
|
|
876 | |
|
|
877 | sub post_detect(&) { |
|
|
878 | my ($cb) = @_; |
|
|
879 | |
|
|
880 | if ($MODEL) { |
|
|
881 | $cb->(); |
|
|
882 | |
|
|
883 | 1 |
|
|
884 | } else { |
|
|
885 | push @post_detect, $cb; |
|
|
886 | |
|
|
887 | defined wantarray |
|
|
888 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
|
|
889 | : () |
|
|
890 | } |
|
|
891 | } |
|
|
892 | |
|
|
893 | sub AnyEvent::Util::PostDetect::DESTROY { |
|
|
894 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
895 | } |
499 | |
896 | |
500 | sub detect() { |
897 | sub detect() { |
501 | unless ($MODEL) { |
898 | unless ($MODEL) { |
502 | no strict 'refs'; |
899 | no strict 'refs'; |
|
|
900 | local $SIG{__DIE__}; |
503 | |
901 | |
504 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
902 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
505 | my $model = "AnyEvent::Impl::$1"; |
903 | my $model = "AnyEvent::Impl::$1"; |
506 | if (eval "require $model") { |
904 | if (eval "require $model") { |
507 | $MODEL = $model; |
905 | $MODEL = $model; |
… | |
… | |
537 | last; |
935 | last; |
538 | } |
936 | } |
539 | } |
937 | } |
540 | |
938 | |
541 | $MODEL |
939 | $MODEL |
542 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
940 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
543 | } |
941 | } |
544 | } |
942 | } |
545 | |
943 | |
|
|
944 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
945 | |
546 | unshift @ISA, $MODEL; |
946 | unshift @ISA, $MODEL; |
547 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
947 | |
|
|
948 | require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; |
|
|
949 | |
|
|
950 | (shift @post_detect)->() while @post_detect; |
548 | } |
951 | } |
549 | |
952 | |
550 | $MODEL |
953 | $MODEL |
551 | } |
954 | } |
552 | |
955 | |
… | |
… | |
562 | $class->$func (@_); |
965 | $class->$func (@_); |
563 | } |
966 | } |
564 | |
967 | |
565 | package AnyEvent::Base; |
968 | package AnyEvent::Base; |
566 | |
969 | |
|
|
970 | # default implementation for now and time |
|
|
971 | |
|
|
972 | use Time::HiRes (); |
|
|
973 | |
|
|
974 | sub time { Time::HiRes::time } |
|
|
975 | sub now { Time::HiRes::time } |
|
|
976 | |
567 | # default implementation for ->condvar, ->wait, ->broadcast |
977 | # default implementation for ->condvar |
568 | |
978 | |
569 | sub condvar { |
979 | sub condvar { |
570 | bless \my $flag, "AnyEvent::Base::CondVar" |
980 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
571 | } |
|
|
572 | |
|
|
573 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
574 | ${$_[0]}++; |
|
|
575 | } |
|
|
576 | |
|
|
577 | sub AnyEvent::Base::CondVar::wait { |
|
|
578 | AnyEvent->one_event while !${$_[0]}; |
|
|
579 | } |
981 | } |
580 | |
982 | |
581 | # default implementation for ->signal |
983 | # default implementation for ->signal |
582 | |
984 | |
583 | our %SIG_CB; |
985 | our %SIG_CB; |
… | |
… | |
599 | sub AnyEvent::Base::Signal::DESTROY { |
1001 | sub AnyEvent::Base::Signal::DESTROY { |
600 | my ($signal, $cb) = @{$_[0]}; |
1002 | my ($signal, $cb) = @{$_[0]}; |
601 | |
1003 | |
602 | delete $SIG_CB{$signal}{$cb}; |
1004 | delete $SIG_CB{$signal}{$cb}; |
603 | |
1005 | |
604 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
1006 | delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; |
605 | } |
1007 | } |
606 | |
1008 | |
607 | # default implementation for ->child |
1009 | # default implementation for ->child |
608 | |
1010 | |
609 | our %PID_CB; |
1011 | our %PID_CB; |
… | |
… | |
636 | or Carp::croak "required option 'pid' is missing"; |
1038 | or Carp::croak "required option 'pid' is missing"; |
637 | |
1039 | |
638 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1040 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
639 | |
1041 | |
640 | unless ($WNOHANG) { |
1042 | unless ($WNOHANG) { |
641 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1043 | $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
642 | } |
1044 | } |
643 | |
1045 | |
644 | unless ($CHLD_W) { |
1046 | unless ($CHLD_W) { |
645 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1047 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
646 | # child could be a zombie already, so make at least one round |
1048 | # child could be a zombie already, so make at least one round |
… | |
… | |
656 | delete $PID_CB{$pid}{$cb}; |
1058 | delete $PID_CB{$pid}{$cb}; |
657 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1059 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
658 | |
1060 | |
659 | undef $CHLD_W unless keys %PID_CB; |
1061 | undef $CHLD_W unless keys %PID_CB; |
660 | } |
1062 | } |
|
|
1063 | |
|
|
1064 | package AnyEvent::CondVar; |
|
|
1065 | |
|
|
1066 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
1067 | |
|
|
1068 | package AnyEvent::CondVar::Base; |
|
|
1069 | |
|
|
1070 | use overload |
|
|
1071 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1072 | fallback => 1; |
|
|
1073 | |
|
|
1074 | sub _send { |
|
|
1075 | # nop |
|
|
1076 | } |
|
|
1077 | |
|
|
1078 | sub send { |
|
|
1079 | my $cv = shift; |
|
|
1080 | $cv->{_ae_sent} = [@_]; |
|
|
1081 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
1082 | $cv->_send; |
|
|
1083 | } |
|
|
1084 | |
|
|
1085 | sub croak { |
|
|
1086 | $_[0]{_ae_croak} = $_[1]; |
|
|
1087 | $_[0]->send; |
|
|
1088 | } |
|
|
1089 | |
|
|
1090 | sub ready { |
|
|
1091 | $_[0]{_ae_sent} |
|
|
1092 | } |
|
|
1093 | |
|
|
1094 | sub _wait { |
|
|
1095 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
1096 | } |
|
|
1097 | |
|
|
1098 | sub recv { |
|
|
1099 | $_[0]->_wait; |
|
|
1100 | |
|
|
1101 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
1102 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
1103 | } |
|
|
1104 | |
|
|
1105 | sub cb { |
|
|
1106 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
1107 | $_[0]{_ae_cb} |
|
|
1108 | } |
|
|
1109 | |
|
|
1110 | sub begin { |
|
|
1111 | ++$_[0]{_ae_counter}; |
|
|
1112 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1113 | } |
|
|
1114 | |
|
|
1115 | sub end { |
|
|
1116 | return if --$_[0]{_ae_counter}; |
|
|
1117 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1118 | } |
|
|
1119 | |
|
|
1120 | # undocumented/compatibility with pre-3.4 |
|
|
1121 | *broadcast = \&send; |
|
|
1122 | *wait = \&_wait; |
661 | |
1123 | |
662 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1124 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
663 | |
1125 | |
664 | This is an advanced topic that you do not normally need to use AnyEvent in |
1126 | This is an advanced topic that you do not normally need to use AnyEvent in |
665 | a module. This section is only of use to event loop authors who want to |
1127 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
719 | C<PERL_ANYEVENT_MODEL>. |
1181 | C<PERL_ANYEVENT_MODEL>. |
720 | |
1182 | |
721 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
1183 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
722 | model it chooses. |
1184 | model it chooses. |
723 | |
1185 | |
|
|
1186 | =item C<PERL_ANYEVENT_STRICT> |
|
|
1187 | |
|
|
1188 | AnyEvent does not do much argument checking by default, as thorough |
|
|
1189 | argument checking is very costly. Setting this variable to a true value |
|
|
1190 | will cause AnyEvent to thoroughly check the arguments passed to most |
|
|
1191 | method calls and croaks if it finds any problems. In other words, enables |
|
|
1192 | "strict" mode. Unlike C<use strict> it is definitely recommended ot keep |
|
|
1193 | it off in production. |
|
|
1194 | |
724 | =item C<PERL_ANYEVENT_MODEL> |
1195 | =item C<PERL_ANYEVENT_MODEL> |
725 | |
1196 | |
726 | This can be used to specify the event model to be used by AnyEvent, before |
1197 | This can be used to specify the event model to be used by AnyEvent, before |
727 | autodetection and -probing kicks in. It must be a string consisting |
1198 | auto detection and -probing kicks in. It must be a string consisting |
728 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1199 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
729 | and the resulting module name is loaded and if the load was successful, |
1200 | and the resulting module name is loaded and if the load was successful, |
730 | used as event model. If it fails to load AnyEvent will proceed with |
1201 | used as event model. If it fails to load AnyEvent will proceed with |
731 | autodetection and -probing. |
1202 | auto detection and -probing. |
732 | |
1203 | |
733 | This functionality might change in future versions. |
1204 | This functionality might change in future versions. |
734 | |
1205 | |
735 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1206 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
736 | could start your program like this: |
1207 | could start your program like this: |
737 | |
1208 | |
738 | PERL_ANYEVENT_MODEL=Perl perl ... |
1209 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1210 | |
|
|
1211 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1212 | |
|
|
1213 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1214 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1215 | of auto probing). |
|
|
1216 | |
|
|
1217 | Must be set to a comma-separated list of protocols or address families, |
|
|
1218 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1219 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1220 | list. |
|
|
1221 | |
|
|
1222 | This variable can effectively be used for denial-of-service attacks |
|
|
1223 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1224 | small, as the program has to handle connection errors already- |
|
|
1225 | |
|
|
1226 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1227 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1228 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1229 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1230 | IPv6, but prefer IPv6 over IPv4. |
|
|
1231 | |
|
|
1232 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1233 | |
|
|
1234 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1235 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1236 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1237 | default. |
|
|
1238 | |
|
|
1239 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1240 | EDNS0 in its DNS requests. |
|
|
1241 | |
|
|
1242 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1243 | |
|
|
1244 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1245 | will create in parallel. |
739 | |
1246 | |
740 | =back |
1247 | =back |
741 | |
1248 | |
742 | =head1 EXAMPLE PROGRAM |
1249 | =head1 EXAMPLE PROGRAM |
743 | |
1250 | |
… | |
… | |
754 | poll => 'r', |
1261 | poll => 'r', |
755 | cb => sub { |
1262 | cb => sub { |
756 | warn "io event <$_[0]>\n"; # will always output <r> |
1263 | warn "io event <$_[0]>\n"; # will always output <r> |
757 | chomp (my $input = <STDIN>); # read a line |
1264 | chomp (my $input = <STDIN>); # read a line |
758 | warn "read: $input\n"; # output what has been read |
1265 | warn "read: $input\n"; # output what has been read |
759 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1266 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
760 | }, |
1267 | }, |
761 | ); |
1268 | ); |
762 | |
1269 | |
763 | my $time_watcher; # can only be used once |
1270 | my $time_watcher; # can only be used once |
764 | |
1271 | |
… | |
… | |
769 | }); |
1276 | }); |
770 | } |
1277 | } |
771 | |
1278 | |
772 | new_timer; # create first timer |
1279 | new_timer; # create first timer |
773 | |
1280 | |
774 | $cv->wait; # wait until user enters /^q/i |
1281 | $cv->recv; # wait until user enters /^q/i |
775 | |
1282 | |
776 | =head1 REAL-WORLD EXAMPLE |
1283 | =head1 REAL-WORLD EXAMPLE |
777 | |
1284 | |
778 | Consider the L<Net::FCP> module. It features (among others) the following |
1285 | Consider the L<Net::FCP> module. It features (among others) the following |
779 | API calls, which are to freenet what HTTP GET requests are to http: |
1286 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
829 | syswrite $txn->{fh}, $txn->{request} |
1336 | syswrite $txn->{fh}, $txn->{request} |
830 | or die "connection or write error"; |
1337 | or die "connection or write error"; |
831 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1338 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
832 | |
1339 | |
833 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1340 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
834 | result and signals any possible waiters that the request ahs finished: |
1341 | result and signals any possible waiters that the request has finished: |
835 | |
1342 | |
836 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1343 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
837 | |
1344 | |
838 | if (end-of-file or data complete) { |
1345 | if (end-of-file or data complete) { |
839 | $txn->{result} = $txn->{buf}; |
1346 | $txn->{result} = $txn->{buf}; |
840 | $txn->{finished}->broadcast; |
1347 | $txn->{finished}->send; |
841 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1348 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
842 | } |
1349 | } |
843 | |
1350 | |
844 | The C<result> method, finally, just waits for the finished signal (if the |
1351 | The C<result> method, finally, just waits for the finished signal (if the |
845 | request was already finished, it doesn't wait, of course, and returns the |
1352 | request was already finished, it doesn't wait, of course, and returns the |
846 | data: |
1353 | data: |
847 | |
1354 | |
848 | $txn->{finished}->wait; |
1355 | $txn->{finished}->recv; |
849 | return $txn->{result}; |
1356 | return $txn->{result}; |
850 | |
1357 | |
851 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1358 | The actual code goes further and collects all errors (C<die>s, exceptions) |
852 | that occured during request processing. The C<result> method detects |
1359 | that occurred during request processing. The C<result> method detects |
853 | whether an exception as thrown (it is stored inside the $txn object) |
1360 | whether an exception as thrown (it is stored inside the $txn object) |
854 | and just throws the exception, which means connection errors and other |
1361 | and just throws the exception, which means connection errors and other |
855 | problems get reported tot he code that tries to use the result, not in a |
1362 | problems get reported tot he code that tries to use the result, not in a |
856 | random callback. |
1363 | random callback. |
857 | |
1364 | |
… | |
… | |
888 | |
1395 | |
889 | my $quit = AnyEvent->condvar; |
1396 | my $quit = AnyEvent->condvar; |
890 | |
1397 | |
891 | $fcp->txn_client_get ($url)->cb (sub { |
1398 | $fcp->txn_client_get ($url)->cb (sub { |
892 | ... |
1399 | ... |
893 | $quit->broadcast; |
1400 | $quit->send; |
894 | }); |
1401 | }); |
895 | |
1402 | |
896 | $quit->wait; |
1403 | $quit->recv; |
897 | |
1404 | |
898 | |
1405 | |
899 | =head1 BENCHMARKS |
1406 | =head1 BENCHMARKS |
900 | |
1407 | |
901 | To give you an idea of the performance and overheads that AnyEvent adds |
1408 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
903 | of various event loops I prepared some benchmarks. |
1410 | of various event loops I prepared some benchmarks. |
904 | |
1411 | |
905 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1412 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
906 | |
1413 | |
907 | Here is a benchmark of various supported event models used natively and |
1414 | Here is a benchmark of various supported event models used natively and |
908 | through anyevent. The benchmark creates a lot of timers (with a zero |
1415 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
909 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1416 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
910 | which it is), lets them fire exactly once and destroys them again. |
1417 | which it is), lets them fire exactly once and destroys them again. |
911 | |
1418 | |
912 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1419 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
913 | distribution. |
1420 | distribution. |
… | |
… | |
930 | all watchers, to avoid adding memory overhead. That means closure creation |
1437 | all watchers, to avoid adding memory overhead. That means closure creation |
931 | and memory usage is not included in the figures. |
1438 | and memory usage is not included in the figures. |
932 | |
1439 | |
933 | I<invoke> is the time, in microseconds, used to invoke a simple |
1440 | I<invoke> is the time, in microseconds, used to invoke a simple |
934 | callback. The callback simply counts down a Perl variable and after it was |
1441 | callback. The callback simply counts down a Perl variable and after it was |
935 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1442 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
936 | signal the end of this phase. |
1443 | signal the end of this phase. |
937 | |
1444 | |
938 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1445 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
939 | watcher. |
1446 | watcher. |
940 | |
1447 | |
… | |
… | |
944 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
1451 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
945 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
1452 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
946 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
1453 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
947 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
1454 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
948 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
1455 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
949 | Event/Any 16000 936 39.17 33.63 1.43 Event + AnyEvent watchers |
1456 | Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers |
950 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
1457 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
951 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
1458 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
952 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
1459 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
953 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
1460 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
954 | |
1461 | |
… | |
… | |
958 | well. For example, a select-based event loop (such as the pure perl one) |
1465 | well. For example, a select-based event loop (such as the pure perl one) |
959 | can never compete with an event loop that uses epoll when the number of |
1466 | can never compete with an event loop that uses epoll when the number of |
960 | file descriptors grows high. In this benchmark, all events become ready at |
1467 | file descriptors grows high. In this benchmark, all events become ready at |
961 | the same time, so select/poll-based implementations get an unnatural speed |
1468 | the same time, so select/poll-based implementations get an unnatural speed |
962 | boost. |
1469 | boost. |
|
|
1470 | |
|
|
1471 | Also, note that the number of watchers usually has a nonlinear effect on |
|
|
1472 | overall speed, that is, creating twice as many watchers doesn't take twice |
|
|
1473 | the time - usually it takes longer. This puts event loops tested with a |
|
|
1474 | higher number of watchers at a disadvantage. |
|
|
1475 | |
|
|
1476 | To put the range of results into perspective, consider that on the |
|
|
1477 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
|
|
1478 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU |
|
|
1479 | cycles with POE. |
963 | |
1480 | |
964 | C<EV> is the sole leader regarding speed and memory use, which are both |
1481 | C<EV> is the sole leader regarding speed and memory use, which are both |
965 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
1482 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
966 | far less memory than any other event loop and is still faster than Event |
1483 | far less memory than any other event loop and is still faster than Event |
967 | natively. |
1484 | natively. |
… | |
… | |
990 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1507 | file descriptor is dup()ed for each watcher. This shows that the dup() |
991 | employed by some adaptors is not a big performance issue (it does incur a |
1508 | employed by some adaptors is not a big performance issue (it does incur a |
992 | hidden memory cost inside the kernel which is not reflected in the figures |
1509 | hidden memory cost inside the kernel which is not reflected in the figures |
993 | above). |
1510 | above). |
994 | |
1511 | |
995 | C<POE>, regardless of underlying event loop (whether using its pure |
1512 | C<POE>, regardless of underlying event loop (whether using its pure perl |
996 | perl select-based backend or the Event module, the POE-EV backend |
1513 | select-based backend or the Event module, the POE-EV backend couldn't |
997 | couldn't be tested because it wasn't working) shows abysmal performance |
1514 | be tested because it wasn't working) shows abysmal performance and |
998 | and memory usage: Watchers use almost 30 times as much memory as |
1515 | memory usage with AnyEvent: Watchers use almost 30 times as much memory |
999 | EV watchers, and 10 times as much memory as Event (the high memory |
1516 | as EV watchers, and 10 times as much memory as Event (the high memory |
1000 | requirements are caused by requiring a session for each watcher). Watcher |
1517 | requirements are caused by requiring a session for each watcher). Watcher |
1001 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
1518 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1519 | implementation. |
|
|
1520 | |
1002 | implementation. The design of the POE adaptor class in AnyEvent can not |
1521 | The design of the POE adaptor class in AnyEvent can not really account |
1003 | really account for this, as session creation overhead is small compared |
1522 | for the performance issues, though, as session creation overhead is |
1004 | to execution of the state machine, which is coded pretty optimally within |
1523 | small compared to execution of the state machine, which is coded pretty |
1005 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
1524 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1525 | using multiple sessions is not a good approach, especially regarding |
|
|
1526 | memory usage, even the author of POE could not come up with a faster |
|
|
1527 | design). |
1006 | |
1528 | |
1007 | =head3 Summary |
1529 | =head3 Summary |
1008 | |
1530 | |
1009 | =over 4 |
1531 | =over 4 |
1010 | |
1532 | |
… | |
… | |
1021 | |
1543 | |
1022 | =back |
1544 | =back |
1023 | |
1545 | |
1024 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1546 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1025 | |
1547 | |
1026 | This benchmark atcually benchmarks the event loop itself. It works by |
1548 | This benchmark actually benchmarks the event loop itself. It works by |
1027 | creating a number of "servers": each server consists of a socketpair, a |
1549 | creating a number of "servers": each server consists of a socket pair, a |
1028 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1550 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1029 | watcher waiting for input on one side of the socket. Each time the socket |
1551 | watcher waiting for input on one side of the socket. Each time the socket |
1030 | watcher reads a byte it will write that byte to a random other "server". |
1552 | watcher reads a byte it will write that byte to a random other "server". |
1031 | |
1553 | |
1032 | The effect is that there will be a lot of I/O watchers, only part of which |
1554 | The effect is that there will be a lot of I/O watchers, only part of which |
1033 | are active at any one point (so there is a constant number of active |
1555 | are active at any one point (so there is a constant number of active |
1034 | fds for each loop iterstaion, but which fds these are is random). The |
1556 | fds for each loop iteration, but which fds these are is random). The |
1035 | timeout is reset each time something is read because that reflects how |
1557 | timeout is reset each time something is read because that reflects how |
1036 | most timeouts work (and puts extra pressure on the event loops). |
1558 | most timeouts work (and puts extra pressure on the event loops). |
1037 | |
1559 | |
1038 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1560 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1039 | (1%) are active. This mirrors the activity of large servers with many |
1561 | (1%) are active. This mirrors the activity of large servers with many |
1040 | connections, most of which are idle at any one point in time. |
1562 | connections, most of which are idle at any one point in time. |
1041 | |
1563 | |
1042 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1564 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1043 | distribution. |
1565 | distribution. |
1044 | |
1566 | |
1045 | =head3 Explanation of the columns |
1567 | =head3 Explanation of the columns |
1046 | |
1568 | |
1047 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1569 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1048 | eahc server has a read and write socket end). |
1570 | each server has a read and write socket end). |
1049 | |
1571 | |
1050 | I<create> is the time it takes to create a socketpair (which is |
1572 | I<create> is the time it takes to create a socket pair (which is |
1051 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1573 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1052 | |
1574 | |
1053 | I<request>, the most important value, is the time it takes to handle a |
1575 | I<request>, the most important value, is the time it takes to handle a |
1054 | single "request", that is, reading the token from the pipe and forwarding |
1576 | single "request", that is, reading the token from the pipe and forwarding |
1055 | it to another server. This includes deleting the old timeout and creating |
1577 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1057 | |
1579 | |
1058 | =head3 Results |
1580 | =head3 Results |
1059 | |
1581 | |
1060 | name sockets create request |
1582 | name sockets create request |
1061 | EV 20000 69.01 11.16 |
1583 | EV 20000 69.01 11.16 |
1062 | Perl 20000 75.28 112.76 |
1584 | Perl 20000 73.32 35.87 |
1063 | Event 20000 212.62 257.32 |
1585 | Event 20000 212.62 257.32 |
1064 | Glib 20000 651.16 1896.30 |
1586 | Glib 20000 651.16 1896.30 |
1065 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1587 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1066 | |
1588 | |
1067 | =head3 Discussion |
1589 | =head3 Discussion |
… | |
… | |
1089 | |
1611 | |
1090 | =head3 Summary |
1612 | =head3 Summary |
1091 | |
1613 | |
1092 | =over 4 |
1614 | =over 4 |
1093 | |
1615 | |
1094 | =item * The pure perl implementation performs extremely well, considering |
1616 | =item * The pure perl implementation performs extremely well. |
1095 | that it uses select. |
|
|
1096 | |
1617 | |
1097 | =item * Avoid Glib or POE in large projects where performance matters. |
1618 | =item * Avoid Glib or POE in large projects where performance matters. |
1098 | |
1619 | |
1099 | =back |
1620 | =back |
1100 | |
1621 | |
… | |
… | |
1113 | |
1634 | |
1114 | =head3 Results |
1635 | =head3 Results |
1115 | |
1636 | |
1116 | name sockets create request |
1637 | name sockets create request |
1117 | EV 16 20.00 6.54 |
1638 | EV 16 20.00 6.54 |
|
|
1639 | Perl 16 25.75 12.62 |
1118 | Event 16 81.27 35.86 |
1640 | Event 16 81.27 35.86 |
1119 | Glib 16 32.63 15.48 |
1641 | Glib 16 32.63 15.48 |
1120 | Perl 16 24.62 162.37 |
|
|
1121 | POE 16 261.87 276.28 uses POE::Loop::Event |
1642 | POE 16 261.87 276.28 uses POE::Loop::Event |
1122 | |
1643 | |
1123 | =head3 Discussion |
1644 | =head3 Discussion |
1124 | |
1645 | |
1125 | The benchmark tries to test the performance of a typical small |
1646 | The benchmark tries to test the performance of a typical small |
1126 | server. While knowing how various event loops perform is interesting, keep |
1647 | server. While knowing how various event loops perform is interesting, keep |
1127 | in mind that their overhead in this case is usually not as important, due |
1648 | in mind that their overhead in this case is usually not as important, due |
1128 | to the small absolute number of watchers. |
1649 | to the small absolute number of watchers (that is, you need efficiency and |
|
|
1650 | speed most when you have lots of watchers, not when you only have a few of |
|
|
1651 | them). |
1129 | |
1652 | |
1130 | EV is again fastest. |
1653 | EV is again fastest. |
1131 | |
1654 | |
1132 | The C-based event loops Event and Glib come in second this time, as the |
1655 | Perl again comes second. It is noticeably faster than the C-based event |
1133 | overhead of running an iteration is much smaller in C than in Perl (little |
1656 | loops Event and Glib, although the difference is too small to really |
1134 | code to execute in the inner loop, and perl's function calling overhead is |
1657 | matter. |
1135 | high, and updating all the data structures is costly). |
|
|
1136 | |
1658 | |
1137 | The pure perl event loop is much slower, but still competitive. |
|
|
1138 | |
|
|
1139 | POE also performs much better in this case, but is is stillf ar behind the |
1659 | POE also performs much better in this case, but is is still far behind the |
1140 | others. |
1660 | others. |
1141 | |
1661 | |
1142 | =head3 Summary |
1662 | =head3 Summary |
1143 | |
1663 | |
1144 | =over 4 |
1664 | =over 4 |
… | |
… | |
1150 | |
1670 | |
1151 | |
1671 | |
1152 | =head1 FORK |
1672 | =head1 FORK |
1153 | |
1673 | |
1154 | Most event libraries are not fork-safe. The ones who are usually are |
1674 | Most event libraries are not fork-safe. The ones who are usually are |
1155 | because they are so inefficient. Only L<EV> is fully fork-aware. |
1675 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
1676 | calls. Only L<EV> is fully fork-aware. |
1156 | |
1677 | |
1157 | If you have to fork, you must either do so I<before> creating your first |
1678 | If you have to fork, you must either do so I<before> creating your first |
1158 | watcher OR you must not use AnyEvent at all in the child. |
1679 | watcher OR you must not use AnyEvent at all in the child. |
1159 | |
1680 | |
1160 | |
1681 | |
… | |
… | |
1168 | specified in the variable. |
1689 | specified in the variable. |
1169 | |
1690 | |
1170 | You can make AnyEvent completely ignore this variable by deleting it |
1691 | You can make AnyEvent completely ignore this variable by deleting it |
1171 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1692 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1172 | |
1693 | |
1173 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1694 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1174 | |
1695 | |
1175 | use AnyEvent; |
1696 | use AnyEvent; |
|
|
1697 | |
|
|
1698 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
1699 | be used to probe what backend is used and gain other information (which is |
|
|
1700 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
|
|
1701 | $ENV{PERL_ANYEGENT_STRICT}. |
|
|
1702 | |
|
|
1703 | |
|
|
1704 | =head1 BUGS |
|
|
1705 | |
|
|
1706 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
|
|
1707 | to work around. If you suffer from memleaks, first upgrade to Perl 5.10 |
|
|
1708 | and check wether the leaks still show up. (Perl 5.10.0 has other annoying |
|
|
1709 | mamleaks, such as leaking on C<map> and C<grep> but it is usually not as |
|
|
1710 | pronounced). |
1176 | |
1711 | |
1177 | |
1712 | |
1178 | =head1 SEE ALSO |
1713 | =head1 SEE ALSO |
1179 | |
1714 | |
1180 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
1715 | Utility functions: L<AnyEvent::Util>. |
1181 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
1716 | |
|
|
1717 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1182 | L<Event::Lib>, L<Qt>, L<POE>. |
1718 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1183 | |
1719 | |
1184 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
1720 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1185 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
1721 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1186 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
1722 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1187 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
1723 | L<AnyEvent::Impl::POE>. |
1188 | |
1724 | |
|
|
1725 | Non-blocking file handles, sockets, TCP clients and |
|
|
1726 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1727 | |
|
|
1728 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
1729 | |
|
|
1730 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
1731 | |
1189 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1732 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1190 | |
1733 | |
1191 | |
1734 | |
1192 | =head1 AUTHOR |
1735 | =head1 AUTHOR |
1193 | |
1736 | |
1194 | Marc Lehmann <schmorp@schmorp.de> |
1737 | Marc Lehmann <schmorp@schmorp.de> |
1195 | http://home.schmorp.de/ |
1738 | http://home.schmorp.de/ |
1196 | |
1739 | |
1197 | =cut |
1740 | =cut |
1198 | |
1741 | |
1199 | 1 |
1742 | 1 |
1200 | |
1743 | |