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17 | }); |
17 | }); |
18 | |
18 | |
19 | my $w = AnyEvent->condvar; # stores wether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores wether a condition was flagged |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->broadcast; # wake up current and all future wait's |
21 | $w->broadcast; # wake up current and all future wait's |
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22 | |
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23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
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24 | |
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25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
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26 | nowadays. So what is different about AnyEvent? |
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27 | |
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28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
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29 | policy> and AnyEvent is I<small and efficient>. |
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30 | |
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31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
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32 | interfaces to whatever event model the main program happens to use in a |
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33 | pragmatic way. For event models and certain classes of immortals alike, |
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34 | the statement "there can only be one" is a bitter reality, and AnyEvent |
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35 | helps hiding the differences. |
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36 | |
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37 | The goal of AnyEvent is to offer module authors the ability to do event |
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38 | programming (waiting for I/O or timer events) without subscribing to a |
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39 | religion, a way of living, and most importantly: without forcing your |
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40 | module users into the same thing by forcing them to use the same event |
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41 | model you use. |
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42 | |
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43 | For modules like POE or IO::Async (which is actually doing all I/O |
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44 | I<synchronously>...), using them in your module is like joining a |
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45 | cult: After you joined, you are dependent on them and you cannot use |
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46 | anything else, as it is simply incompatible to everything that isn't |
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47 | itself. |
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48 | |
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49 | AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk |
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50 | works fine etc. etc. but none of these work together with the rest: POE |
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51 | + IO::Async? no go. Tk + Event? no go. If your module uses one of |
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52 | those, every user of your module has to use it, too. If your module |
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53 | uses AnyEvent, it works transparently with all event models it supports |
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54 | (including stuff like POE and IO::Async). |
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55 | |
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56 | In addition of being free of having to use I<the one and only true event |
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57 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
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58 | modules, you get an enourmous amount of code and strict rules you have |
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59 | to follow. AnyEvent, on the other hand, is lean and to the point by only |
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60 | offering the functionality that is useful, in as thin as a wrapper as |
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61 | technically possible. |
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62 | |
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63 | Of course, if you want lots of policy (this can arguably be somewhat |
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64 | useful) and you want to force your users to use the one and only event |
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65 | model, you should I<not> use this module. |
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66 | |
22 | |
67 | |
23 | =head1 DESCRIPTION |
68 | =head1 DESCRIPTION |
24 | |
69 | |
25 | L<AnyEvent> provides an identical interface to multiple event loops. This |
70 | L<AnyEvent> provides an identical interface to multiple event loops. This |
26 | allows module authors to utilise an event loop without forcing module |
71 | allows module authors to utilise an event loop without forcing module |
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119 | method without any arguments. |
164 | method without any arguments. |
120 | |
165 | |
121 | A condition watcher watches for a condition - precisely that the C<< |
166 | A condition watcher watches for a condition - precisely that the C<< |
122 | ->broadcast >> method has been called. |
167 | ->broadcast >> method has been called. |
123 | |
168 | |
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169 | Note that condition watchers recurse into the event loop - if you have |
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170 | two watchers that call C<< ->wait >> in a round-robbin fashion, you |
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171 | lose. Therefore, condition watchers are good to export to your caller, but |
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172 | you should avoid making a blocking wait, at least in callbacks, as this |
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173 | usually asks for trouble. |
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174 | |
124 | The watcher has only two methods: |
175 | The watcher has only two methods: |
125 | |
176 | |
126 | =over 4 |
177 | =over 4 |
127 | |
178 | |
128 | =item $cv->wait |
179 | =item $cv->wait |
129 | |
180 | |
130 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
181 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
131 | called on c<$cv>, while servicing other watchers normally. |
182 | called on c<$cv>, while servicing other watchers normally. |
132 | |
183 | |
133 | Not all event models support a blocking wait - some die in that case, so |
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134 | if you are using this from a module, never require a blocking wait, but |
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135 | let the caller decide wether the call will block or not (for example, |
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136 | by coupling condition variables with some kind of request results and |
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137 | supporting callbacks so the caller knows that getting the result will not |
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138 | block, while still suppporting blockign waits if the caller so desires). |
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139 | |
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140 | You can only wait once on a condition - additional calls will return |
184 | You can only wait once on a condition - additional calls will return |
141 | immediately. |
185 | immediately. |
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186 | |
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187 | Not all event models support a blocking wait - some die in that case |
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188 | (programs might want to do that so they stay interactive), so I<if you |
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189 | are using this from a module, never require a blocking wait>, but let the |
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190 | caller decide wether the call will block or not (for example, by coupling |
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191 | condition variables with some kind of request results and supporting |
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192 | callbacks so the caller knows that getting the result will not block, |
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193 | while still suppporting blocking waits if the caller so desires). |
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194 | |
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195 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
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196 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
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197 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
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198 | can supply (the coroutine-aware backends C<Coro::EV> and C<Coro::Event> |
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199 | explicitly support concurrent C<< ->wait >>'s from different coroutines, |
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200 | however). |
142 | |
201 | |
143 | =item $cv->broadcast |
202 | =item $cv->broadcast |
144 | |
203 | |
145 | Flag the condition as ready - a running C<< ->wait >> and all further |
204 | Flag the condition as ready - a running C<< ->wait >> and all further |
146 | calls to C<wait> will return after this method has been called. If nobody |
205 | calls to C<wait> will return after this method has been called. If nobody |
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201 | |
260 | |
202 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
261 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
203 | AnyEvent::Impl::EV based on EV (an interface to libev, also best choice). |
262 | AnyEvent::Impl::EV based on EV (an interface to libev, also best choice). |
204 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
263 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
205 | AnyEvent::Impl::Event based on Event, also second best choice :) |
264 | AnyEvent::Impl::Event based on Event, also second best choice :) |
206 | AnyEvent::Impl::Glib based on Glib, second-best choice. |
265 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
207 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
266 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
208 | AnyEvent::Impl::Perl pure-perl implementation, inefficient. |
267 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
209 | |
268 | |
210 | =item AnyEvent::detect |
269 | =item AnyEvent::detect |
211 | |
270 | |
212 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if |
271 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if |
213 | necessary. You should only call this function right before you would have |
272 | necessary. You should only call this function right before you would have |
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252 | no warnings; |
311 | no warnings; |
253 | use strict; |
312 | use strict; |
254 | |
313 | |
255 | use Carp; |
314 | use Carp; |
256 | |
315 | |
257 | our $VERSION = '2.9'; |
316 | our $VERSION = '3.0'; |
258 | our $MODEL; |
317 | our $MODEL; |
259 | |
318 | |
260 | our $AUTOLOAD; |
319 | our $AUTOLOAD; |
261 | our @ISA; |
320 | our @ISA; |
262 | |
321 | |