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 | Event, Coro, Glib, Tk - various supported event loops |
5 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib - various supported event loops |
6 | |
6 | |
7 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
8 | |
8 | |
9 | use AnyEvent; |
9 | use AnyEvent; |
10 | |
10 | |
11 | my $w = AnyEvent->io (fh => ..., poll => "[rw]+", cb => sub { |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
12 | my ($poll_got) = @_; |
|
|
13 | ... |
12 | ... |
14 | }); |
13 | }); |
15 | |
|
|
16 | - only one io watcher per $fh and $poll type is allowed |
|
|
17 | (i.e. on a socket you can have one r + one w or one rw |
|
|
18 | watcher, not any more. |
|
|
19 | |
|
|
20 | - AnyEvent will keep filehandles alive, so as long as the watcher exists, |
|
|
21 | the filehandle exists. |
|
|
22 | |
14 | |
23 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
24 | ... |
16 | ... |
25 | }); |
17 | }); |
26 | |
18 | |
27 | - io and time watchers get canceled whenever $w is destroyed, so keep a copy |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
28 | |
|
|
29 | - timers can only be used once and must be recreated for repeated operation |
|
|
30 | |
|
|
31 | my $w = AnyEvent->condvar; # kind of main loop replacement |
|
|
32 | $w->wait; # enters main loop till $condvar gets ->broadcast |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
33 | $w->broadcast; # wake up current and all future wait's |
21 | $w->broadcast; # wake up current and all future wait's |
34 | |
22 | |
35 | - condvars are used to give blocking behaviour when neccessary. Create |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
36 | a condvar for any "request" or "event" your module might create, C<< |
24 | |
37 | ->broadcast >> it when the event happens and provide a function that calls |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
38 | C<< ->wait >> for it. See the examples below. |
26 | nowadays. So what is different about AnyEvent? |
|
|
27 | |
|
|
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
|
|
29 | policy> and AnyEvent is I<small and efficient>. |
|
|
30 | |
|
|
31 | 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 |
|
|
33 | 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, |
|
|
35 | only one event loop can be active at the same time in a process. AnyEvent |
|
|
36 | helps hiding the differences between those event loops. |
|
|
37 | |
|
|
38 | 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 |
|
|
40 | 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 |
|
|
42 | model you use. |
|
|
43 | |
|
|
44 | 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 |
|
|
46 | 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 |
|
|
48 | isn't itself. What's worse, all the potential users of your module are |
|
|
49 | I<also> forced to use the same event loop you use. |
|
|
50 | |
|
|
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
|
|
52 | 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 |
|
|
54 | 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 |
|
|
56 | event models it supports (including stuff like POE and IO::Async, as long |
|
|
57 | as those use one of the supported event loops. It is trivial to add new |
|
|
58 | event loops to AnyEvent, too, so it is future-proof). |
|
|
59 | |
|
|
60 | 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 |
|
|
62 | modules, you get an enourmous 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 |
|
|
64 | offering the functionality that is necessary, in as thin as a wrapper as |
|
|
65 | technically possible. |
|
|
66 | |
|
|
67 | Of course, if you 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 |
|
|
69 | model, you should I<not> use this module. |
|
|
70 | |
39 | |
71 | |
40 | =head1 DESCRIPTION |
72 | =head1 DESCRIPTION |
41 | |
73 | |
42 | L<AnyEvent> provides an identical interface to multiple event loops. This |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
43 | allows module authors to utilizy an event loop without forcing module |
75 | allows module authors to utilise an event loop without forcing module |
44 | users to use the same event loop (as only a single event loop can coexist |
76 | users to use the same event loop (as only a single event loop can coexist |
45 | peacefully at any one time). |
77 | peacefully at any one time). |
46 | |
78 | |
47 | The interface itself is vaguely similar but not identical to the Event |
79 | The interface itself is vaguely similar, but not identical to the L<Event> |
48 | module. |
80 | module. |
49 | |
81 | |
50 | On the first call of any method, the module tries to detect the currently |
82 | During the first call of any watcher-creation method, the module tries |
51 | loaded event loop by probing wether any of the following modules is |
83 | to detect the currently loaded event loop by probing whether one of the |
52 | loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
53 | used. If none is found, the module tries to load these modules in the |
85 | L<Event>, L<Glib>, L<Tk>. The first one found is used. If none are found, |
54 | order given. The first one that could be successfully loaded will be |
86 | the module tries to load these modules in the stated order. The first one |
55 | used. If still none could be found, it will issue an error. |
87 | that can be successfully loaded will be used. If, after this, still none |
|
|
88 | could be found, AnyEvent will fall back to a pure-perl event loop, which |
|
|
89 | is not very efficient, but should work everywhere. |
|
|
90 | |
|
|
91 | Because AnyEvent first checks for modules that are already loaded, loading |
|
|
92 | an event model explicitly before first using AnyEvent will likely make |
|
|
93 | that model the default. For example: |
|
|
94 | |
|
|
95 | use Tk; |
|
|
96 | use AnyEvent; |
|
|
97 | |
|
|
98 | # .. AnyEvent will likely default to Tk |
|
|
99 | |
|
|
100 | The I<likely> means that, if any module loads another event model and |
|
|
101 | starts using it, all bets are off. Maybe you should tell their authors to |
|
|
102 | use AnyEvent so their modules work together with others seamlessly... |
|
|
103 | |
|
|
104 | The pure-perl implementation of AnyEvent is called |
|
|
105 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
|
|
106 | explicitly. |
|
|
107 | |
|
|
108 | =head1 WATCHERS |
|
|
109 | |
|
|
110 | AnyEvent has the central concept of a I<watcher>, which is an object that |
|
|
111 | stores relevant data for each kind of event you are waiting for, such as |
|
|
112 | the callback to call, the filehandle to watch, etc. |
|
|
113 | |
|
|
114 | These watchers are normal Perl objects with normal Perl lifetime. After |
|
|
115 | creating a watcher it will immediately "watch" for events and invoke the |
|
|
116 | callback when the event occurs (of course, only when the event model |
|
|
117 | is in control). |
|
|
118 | |
|
|
119 | To disable the watcher you have to destroy it (e.g. by setting the |
|
|
120 | variable you store it in to C<undef> or otherwise deleting all references |
|
|
121 | to it). |
|
|
122 | |
|
|
123 | All watchers are created by calling a method on the C<AnyEvent> class. |
|
|
124 | |
|
|
125 | Many watchers either are used with "recursion" (repeating timers for |
|
|
126 | example), or need to refer to their watcher object in other ways. |
|
|
127 | |
|
|
128 | An any way to achieve that is this pattern: |
|
|
129 | |
|
|
130 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
|
|
131 | # you can use $w here, for example to undef it |
|
|
132 | undef $w; |
|
|
133 | }); |
|
|
134 | |
|
|
135 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
|
|
136 | my variables are only visible after the statement in which they are |
|
|
137 | declared. |
|
|
138 | |
|
|
139 | =head2 IO WATCHERS |
|
|
140 | |
|
|
141 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
|
|
142 | with the following mandatory key-value pairs as arguments: |
|
|
143 | |
|
|
144 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
|
|
145 | events. C<poll> must be a string that is either C<r> or C<w>, which |
|
|
146 | creates a watcher waiting for "r"eadable or "w"ritable events, |
|
|
147 | respectively. C<cb> is the callback to invoke each time the file handle |
|
|
148 | becomes ready. |
|
|
149 | |
|
|
150 | File handles will be kept alive, so as long as the watcher exists, the |
|
|
151 | file handle exists, too. |
|
|
152 | |
|
|
153 | It is not allowed to close a file handle as long as any watcher is active |
|
|
154 | on the underlying file descriptor. |
|
|
155 | |
|
|
156 | Some event loops issue spurious readyness notifications, so you should |
|
|
157 | always use non-blocking calls when reading/writing from/to your file |
|
|
158 | handles. |
|
|
159 | |
|
|
160 | Example: |
|
|
161 | |
|
|
162 | # wait for readability of STDIN, then read a line and disable the watcher |
|
|
163 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
|
|
164 | chomp (my $input = <STDIN>); |
|
|
165 | warn "read: $input\n"; |
|
|
166 | undef $w; |
|
|
167 | }); |
|
|
168 | |
|
|
169 | =head2 TIME WATCHERS |
|
|
170 | |
|
|
171 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
|
|
172 | method with the following mandatory arguments: |
|
|
173 | |
|
|
174 | C<after> specifies after how many seconds (fractional values are |
|
|
175 | supported) should the timer activate. C<cb> the callback to invoke in that |
|
|
176 | case. |
|
|
177 | |
|
|
178 | The timer callback will be invoked at most once: if you want a repeating |
|
|
179 | timer you have to create a new watcher (this is a limitation by both Tk |
|
|
180 | and Glib). |
|
|
181 | |
|
|
182 | Example: |
|
|
183 | |
|
|
184 | # fire an event after 7.7 seconds |
|
|
185 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
|
|
186 | warn "timeout\n"; |
|
|
187 | }); |
|
|
188 | |
|
|
189 | # to cancel the timer: |
|
|
190 | undef $w; |
|
|
191 | |
|
|
192 | Example 2: |
|
|
193 | |
|
|
194 | # fire an event after 0.5 seconds, then roughly every second |
|
|
195 | my $w; |
|
|
196 | |
|
|
197 | my $cb = sub { |
|
|
198 | # cancel the old timer while creating a new one |
|
|
199 | $w = AnyEvent->timer (after => 1, cb => $cb); |
|
|
200 | }; |
|
|
201 | |
|
|
202 | # start the "loop" by creating the first watcher |
|
|
203 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
|
|
204 | |
|
|
205 | =head3 TIMING ISSUES |
|
|
206 | |
|
|
207 | There are two ways to handle timers: based on real time (relative, "fire |
|
|
208 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
|
|
209 | o'clock"). |
|
|
210 | |
|
|
211 | While most event loops expect timers to specified in a relative way, they use |
|
|
212 | absolute time internally. This makes a difference when your clock "jumps", |
|
|
213 | for example, when ntp decides to set your clock backwards from the wrong 2014-01-01 to |
|
|
214 | 2008-01-01, a watcher that you created to fire "after" a second might actually take |
|
|
215 | six years to finally fire. |
|
|
216 | |
|
|
217 | AnyEvent cannot compensate for this. The only event loop that is conscious |
|
|
218 | about these issues is L<EV>, which offers both relative (ev_timer) and |
|
|
219 | absolute (ev_periodic) timers. |
|
|
220 | |
|
|
221 | AnyEvent always prefers relative timers, if available, matching the |
|
|
222 | AnyEvent API. |
|
|
223 | |
|
|
224 | =head2 SIGNAL WATCHERS |
|
|
225 | |
|
|
226 | You can watch for signals using a signal watcher, C<signal> is the signal |
|
|
227 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
|
|
228 | be invoked whenever a signal occurs. |
|
|
229 | |
|
|
230 | Multiple signals occurances can be clumped together into one callback |
|
|
231 | invocation, and callback invocation will be synchronous. synchronous means |
|
|
232 | that it might take a while until the signal gets handled by the process, |
|
|
233 | but it is guarenteed not to interrupt any other callbacks. |
|
|
234 | |
|
|
235 | The main advantage of using these watchers is that you can share a signal |
|
|
236 | between multiple watchers. |
|
|
237 | |
|
|
238 | This watcher might use C<%SIG>, so programs overwriting those signals |
|
|
239 | directly will likely not work correctly. |
|
|
240 | |
|
|
241 | Example: exit on SIGINT |
|
|
242 | |
|
|
243 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
|
|
244 | |
|
|
245 | =head2 CHILD PROCESS WATCHERS |
|
|
246 | |
|
|
247 | You can also watch on a child process exit and catch its exit status. |
|
|
248 | |
|
|
249 | The child process is specified by the C<pid> argument (if set to C<0>, it |
|
|
250 | watches for any child process exit). The watcher will trigger as often |
|
|
251 | as status change for the child are received. This works by installing a |
|
|
252 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
|
|
253 | and exit status (as returned by waitpid). |
|
|
254 | |
|
|
255 | Example: wait for pid 1333 |
|
|
256 | |
|
|
257 | my $w = AnyEvent->child ( |
|
|
258 | pid => 1333, |
|
|
259 | cb => sub { |
|
|
260 | my ($pid, $status) = @_; |
|
|
261 | warn "pid $pid exited with status $status"; |
|
|
262 | }, |
|
|
263 | ); |
|
|
264 | |
|
|
265 | =head2 CONDITION VARIABLES |
|
|
266 | |
|
|
267 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
|
|
268 | method without any arguments. |
|
|
269 | |
|
|
270 | A condition variable waits for a condition - precisely that the C<< |
|
|
271 | ->broadcast >> method has been called. |
|
|
272 | |
|
|
273 | They are very useful to signal that a condition has been fulfilled, for |
|
|
274 | example, if you write a module that does asynchronous http requests, |
|
|
275 | then a condition variable would be the ideal candidate to signal the |
|
|
276 | availability of results. |
|
|
277 | |
|
|
278 | You can also use condition variables to block your main program until |
|
|
279 | an event occurs - for example, you could C<< ->wait >> in your main |
|
|
280 | program until the user clicks the Quit button in your app, which would C<< |
|
|
281 | ->broadcast >> the "quit" event. |
|
|
282 | |
|
|
283 | Note that condition variables recurse into the event loop - if you have |
|
|
284 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
|
|
285 | lose. Therefore, condition variables are good to export to your caller, but |
|
|
286 | you should avoid making a blocking wait yourself, at least in callbacks, |
|
|
287 | as this asks for trouble. |
|
|
288 | |
|
|
289 | This object has two methods: |
56 | |
290 | |
57 | =over 4 |
291 | =over 4 |
58 | |
292 | |
|
|
293 | =item $cv->wait |
|
|
294 | |
|
|
295 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
|
|
296 | called on c<$cv>, while servicing other watchers normally. |
|
|
297 | |
|
|
298 | You can only wait once on a condition - additional calls will return |
|
|
299 | immediately. |
|
|
300 | |
|
|
301 | Not all event models support a blocking wait - some die in that case |
|
|
302 | (programs might want to do that to stay interactive), so I<if you are |
|
|
303 | using this from a module, never require a blocking wait>, but let the |
|
|
304 | caller decide whether the call will block or not (for example, by coupling |
|
|
305 | condition variables with some kind of request results and supporting |
|
|
306 | callbacks so the caller knows that getting the result will not block, |
|
|
307 | while still suppporting blocking waits if the caller so desires). |
|
|
308 | |
|
|
309 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
|
|
310 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
|
|
311 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
|
|
312 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
|
|
313 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
314 | from different coroutines, however). |
|
|
315 | |
|
|
316 | =item $cv->broadcast |
|
|
317 | |
|
|
318 | Flag the condition as ready - a running C<< ->wait >> and all further |
|
|
319 | calls to C<wait> will (eventually) return after this method has been |
|
|
320 | called. If nobody is waiting the broadcast will be remembered.. |
|
|
321 | |
|
|
322 | =back |
|
|
323 | |
|
|
324 | Example: |
|
|
325 | |
|
|
326 | # wait till the result is ready |
|
|
327 | my $result_ready = AnyEvent->condvar; |
|
|
328 | |
|
|
329 | # do something such as adding a timer |
|
|
330 | # or socket watcher the calls $result_ready->broadcast |
|
|
331 | # when the "result" is ready. |
|
|
332 | # in this case, we simply use a timer: |
|
|
333 | my $w = AnyEvent->timer ( |
|
|
334 | after => 1, |
|
|
335 | cb => sub { $result_ready->broadcast }, |
|
|
336 | ); |
|
|
337 | |
|
|
338 | # this "blocks" (while handling events) till the watcher |
|
|
339 | # calls broadcast |
|
|
340 | $result_ready->wait; |
|
|
341 | |
|
|
342 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
|
|
343 | |
|
|
344 | =over 4 |
|
|
345 | |
|
|
346 | =item $AnyEvent::MODEL |
|
|
347 | |
|
|
348 | Contains C<undef> until the first watcher is being created. Then it |
|
|
349 | contains the event model that is being used, which is the name of the |
|
|
350 | Perl class implementing the model. This class is usually one of the |
|
|
351 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
|
|
352 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
|
|
353 | |
|
|
354 | The known classes so far are: |
|
|
355 | |
|
|
356 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
357 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
358 | AnyEvent::Impl::EV based on EV (an interface to libev, also best choice). |
|
|
359 | AnyEvent::Impl::Event based on Event, also second best choice :) |
|
|
360 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
|
|
361 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
|
|
362 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
363 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
|
|
364 | |
|
|
365 | =item AnyEvent::detect |
|
|
366 | |
|
|
367 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
|
|
368 | if necessary. You should only call this function right before you would |
|
|
369 | have created an AnyEvent watcher anyway, that is, as late as possible at |
|
|
370 | runtime. |
|
|
371 | |
|
|
372 | =back |
|
|
373 | |
|
|
374 | =head1 WHAT TO DO IN A MODULE |
|
|
375 | |
|
|
376 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
|
|
377 | freely, but you should not load a specific event module or rely on it. |
|
|
378 | |
|
|
379 | Be careful when you create watchers in the module body - AnyEvent will |
|
|
380 | decide which event module to use as soon as the first method is called, so |
|
|
381 | by calling AnyEvent in your module body you force the user of your module |
|
|
382 | to load the event module first. |
|
|
383 | |
|
|
384 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
|
|
385 | the C<< ->broadcast >> method has been called on it already. This is |
|
|
386 | because it will stall the whole program, and the whole point of using |
|
|
387 | events is to stay interactive. |
|
|
388 | |
|
|
389 | It is fine, however, to call C<< ->wait >> when the user of your module |
|
|
390 | requests it (i.e. if you create a http request object ad have a method |
|
|
391 | called C<results> that returns the results, it should call C<< ->wait >> |
|
|
392 | freely, as the user of your module knows what she is doing. always). |
|
|
393 | |
|
|
394 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
|
|
395 | |
|
|
396 | There will always be a single main program - the only place that should |
|
|
397 | dictate which event model to use. |
|
|
398 | |
|
|
399 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
|
|
400 | do anything special (it does not need to be event-based) and let AnyEvent |
|
|
401 | decide which implementation to chose if some module relies on it. |
|
|
402 | |
|
|
403 | If the main program relies on a specific event model. For example, in |
|
|
404 | Gtk2 programs you have to rely on the Glib module. You should load the |
|
|
405 | event module before loading AnyEvent or any module that uses it: generally |
|
|
406 | speaking, you should load it as early as possible. The reason is that |
|
|
407 | modules might create watchers when they are loaded, and AnyEvent will |
|
|
408 | decide on the event model to use as soon as it creates watchers, and it |
|
|
409 | might chose the wrong one unless you load the correct one yourself. |
|
|
410 | |
|
|
411 | You can chose to use a rather inefficient pure-perl implementation by |
|
|
412 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
|
|
413 | behaviour everywhere, but letting AnyEvent chose is generally better. |
|
|
414 | |
59 | =cut |
415 | =cut |
60 | |
416 | |
61 | package AnyEvent; |
417 | package AnyEvent; |
62 | |
418 | |
63 | no warnings; |
419 | no warnings; |
64 | use strict 'vars'; |
420 | use strict; |
|
|
421 | |
65 | use Carp; |
422 | use Carp; |
66 | |
423 | |
67 | our $VERSION = 0.3; |
424 | our $VERSION = '3.12'; |
68 | our $MODEL; |
425 | our $MODEL; |
69 | |
426 | |
70 | our $AUTOLOAD; |
427 | our $AUTOLOAD; |
71 | our @ISA; |
428 | our @ISA; |
72 | |
429 | |
|
|
430 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
|
|
431 | |
|
|
432 | our @REGISTRY; |
|
|
433 | |
73 | my @models = ( |
434 | my @models = ( |
74 | [Coro => Coro::Event::], |
435 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
75 | [Event => Event::], |
436 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
76 | [Glib => Glib::], |
437 | [EV:: => AnyEvent::Impl::EV::], |
77 | [Tk => Tk::], |
438 | [Event:: => AnyEvent::Impl::Event::], |
|
|
439 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
440 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
441 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
|
|
442 | [Event::Lib:: => AnyEvent::Impl::EventLib::], |
78 | ); |
443 | ); |
79 | |
444 | |
80 | our %method = map +($_ => 1), qw(io timer condvar broadcast wait cancel DESTROY); |
445 | our %method = map +($_ => 1), qw(io timer condvar broadcast wait signal one_event DESTROY); |
81 | |
446 | |
82 | sub AUTOLOAD { |
447 | sub detect() { |
83 | $AUTOLOAD =~ s/.*://; |
|
|
84 | |
|
|
85 | $method{$AUTOLOAD} |
|
|
86 | or croak "$AUTOLOAD: not a valid method for AnyEvent objects"; |
|
|
87 | |
|
|
88 | unless ($MODEL) { |
448 | unless ($MODEL) { |
89 | # check for already loaded models |
449 | no strict 'refs'; |
90 | for (@models) { |
450 | |
91 | my ($model, $package) = @$_; |
451 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
92 | if (scalar keys %{ *{"$package\::"} }) { |
452 | my $model = "AnyEvent::Impl::$1"; |
93 | eval "require AnyEvent::Impl::$model"; |
453 | if (eval "require $model") { |
94 | last if $MODEL; |
454 | $MODEL = $model; |
|
|
455 | warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; |
95 | } |
456 | } |
96 | } |
457 | } |
97 | |
458 | |
|
|
459 | # check for already loaded models |
98 | unless ($MODEL) { |
460 | unless ($MODEL) { |
99 | # try to load a model |
|
|
100 | |
|
|
101 | for (@models) { |
461 | for (@REGISTRY, @models) { |
102 | my ($model, $package) = @$_; |
462 | my ($package, $model) = @$_; |
103 | eval "require AnyEvent::Impl::$model"; |
463 | if (${"$package\::VERSION"} > 0) { |
104 | last if $MODEL; |
464 | if (eval "require $model") { |
|
|
465 | $MODEL = $model; |
|
|
466 | warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; |
|
|
467 | last; |
|
|
468 | } |
|
|
469 | } |
105 | } |
470 | } |
106 | |
471 | |
|
|
472 | unless ($MODEL) { |
|
|
473 | # try to load a model |
|
|
474 | |
|
|
475 | for (@REGISTRY, @models) { |
|
|
476 | my ($package, $model) = @$_; |
|
|
477 | if (eval "require $package" |
|
|
478 | and ${"$package\::VERSION"} > 0 |
|
|
479 | and eval "require $model") { |
|
|
480 | $MODEL = $model; |
|
|
481 | warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; |
|
|
482 | last; |
|
|
483 | } |
|
|
484 | } |
|
|
485 | |
107 | $MODEL |
486 | $MODEL |
108 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk."; |
487 | 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."; |
|
|
488 | } |
109 | } |
489 | } |
|
|
490 | |
|
|
491 | unshift @ISA, $MODEL; |
|
|
492 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
110 | } |
493 | } |
111 | |
494 | |
112 | @ISA = $MODEL; |
495 | $MODEL |
|
|
496 | } |
|
|
497 | |
|
|
498 | sub AUTOLOAD { |
|
|
499 | (my $func = $AUTOLOAD) =~ s/.*://; |
|
|
500 | |
|
|
501 | $method{$func} |
|
|
502 | or croak "$func: not a valid method for AnyEvent objects"; |
|
|
503 | |
|
|
504 | detect unless $MODEL; |
113 | |
505 | |
114 | my $class = shift; |
506 | my $class = shift; |
115 | $class->$AUTOLOAD (@_); |
507 | $class->$func (@_); |
116 | } |
508 | } |
|
|
509 | |
|
|
510 | package AnyEvent::Base; |
|
|
511 | |
|
|
512 | # default implementation for ->condvar, ->wait, ->broadcast |
|
|
513 | |
|
|
514 | sub condvar { |
|
|
515 | bless \my $flag, "AnyEvent::Base::CondVar" |
|
|
516 | } |
|
|
517 | |
|
|
518 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
519 | ${$_[0]}++; |
|
|
520 | } |
|
|
521 | |
|
|
522 | sub AnyEvent::Base::CondVar::wait { |
|
|
523 | AnyEvent->one_event while !${$_[0]}; |
|
|
524 | } |
|
|
525 | |
|
|
526 | # default implementation for ->signal |
|
|
527 | |
|
|
528 | our %SIG_CB; |
|
|
529 | |
|
|
530 | sub signal { |
|
|
531 | my (undef, %arg) = @_; |
|
|
532 | |
|
|
533 | my $signal = uc $arg{signal} |
|
|
534 | or Carp::croak "required option 'signal' is missing"; |
|
|
535 | |
|
|
536 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
|
|
537 | $SIG{$signal} ||= sub { |
|
|
538 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
|
|
539 | }; |
|
|
540 | |
|
|
541 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
|
|
542 | } |
|
|
543 | |
|
|
544 | sub AnyEvent::Base::Signal::DESTROY { |
|
|
545 | my ($signal, $cb) = @{$_[0]}; |
|
|
546 | |
|
|
547 | delete $SIG_CB{$signal}{$cb}; |
|
|
548 | |
|
|
549 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
|
|
550 | } |
|
|
551 | |
|
|
552 | # default implementation for ->child |
|
|
553 | |
|
|
554 | our %PID_CB; |
|
|
555 | our $CHLD_W; |
|
|
556 | our $CHLD_DELAY_W; |
|
|
557 | our $PID_IDLE; |
|
|
558 | our $WNOHANG; |
|
|
559 | |
|
|
560 | sub _child_wait { |
|
|
561 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
|
|
562 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
|
|
563 | (values %{ $PID_CB{0} || {} }); |
|
|
564 | } |
|
|
565 | |
|
|
566 | undef $PID_IDLE; |
|
|
567 | } |
|
|
568 | |
|
|
569 | sub _sigchld { |
|
|
570 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
571 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
572 | undef $CHLD_DELAY_W; |
|
|
573 | &_child_wait; |
|
|
574 | }); |
|
|
575 | } |
|
|
576 | |
|
|
577 | sub child { |
|
|
578 | my (undef, %arg) = @_; |
|
|
579 | |
|
|
580 | defined (my $pid = $arg{pid} + 0) |
|
|
581 | or Carp::croak "required option 'pid' is missing"; |
|
|
582 | |
|
|
583 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
|
|
584 | |
|
|
585 | unless ($WNOHANG) { |
|
|
586 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
|
|
587 | } |
|
|
588 | |
|
|
589 | unless ($CHLD_W) { |
|
|
590 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
|
|
591 | # child could be a zombie already, so make at least one round |
|
|
592 | &_sigchld; |
|
|
593 | } |
|
|
594 | |
|
|
595 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
|
|
596 | } |
|
|
597 | |
|
|
598 | sub AnyEvent::Base::Child::DESTROY { |
|
|
599 | my ($pid, $cb) = @{$_[0]}; |
|
|
600 | |
|
|
601 | delete $PID_CB{$pid}{$cb}; |
|
|
602 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
|
|
603 | |
|
|
604 | undef $CHLD_W unless keys %PID_CB; |
|
|
605 | } |
|
|
606 | |
|
|
607 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
|
|
608 | |
|
|
609 | This is an advanced topic that you do not normally need to use AnyEvent in |
|
|
610 | a module. This section is only of use to event loop authors who want to |
|
|
611 | provide AnyEvent compatibility. |
|
|
612 | |
|
|
613 | If you need to support another event library which isn't directly |
|
|
614 | supported by AnyEvent, you can supply your own interface to it by |
|
|
615 | pushing, before the first watcher gets created, the package name of |
|
|
616 | the event module and the package name of the interface to use onto |
|
|
617 | C<@AnyEvent::REGISTRY>. You can do that before and even without loading |
|
|
618 | AnyEvent, so it is reasonably cheap. |
|
|
619 | |
|
|
620 | Example: |
|
|
621 | |
|
|
622 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
|
|
623 | |
|
|
624 | This tells AnyEvent to (literally) use the C<urxvt::anyevent::> |
|
|
625 | package/class when it finds the C<urxvt> package/module is already loaded. |
|
|
626 | |
|
|
627 | When AnyEvent is loaded and asked to find a suitable event model, it |
|
|
628 | will first check for the presence of urxvt by trying to C<use> the |
|
|
629 | C<urxvt::anyevent> module. |
|
|
630 | |
|
|
631 | The class should provide implementations for all watcher types. See |
|
|
632 | L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code) |
|
|
633 | and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to |
|
|
634 | see the sources. |
|
|
635 | |
|
|
636 | If you don't provide C<signal> and C<child> watchers than AnyEvent will |
|
|
637 | provide suitable (hopefully) replacements. |
|
|
638 | |
|
|
639 | The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) |
|
|
640 | terminal emulator uses the above line as-is. An interface isn't included |
|
|
641 | in AnyEvent because it doesn't make sense outside the embedded interpreter |
|
|
642 | inside I<rxvt-unicode>, and it is updated and maintained as part of the |
|
|
643 | I<rxvt-unicode> distribution. |
|
|
644 | |
|
|
645 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
|
|
646 | condition variables: code blocking while waiting for a condition will |
|
|
647 | C<die>. This still works with most modules/usages, and blocking calls must |
|
|
648 | not be done in an interactive application, so it makes sense. |
|
|
649 | |
|
|
650 | =head1 ENVIRONMENT VARIABLES |
|
|
651 | |
|
|
652 | The following environment variables are used by this module: |
|
|
653 | |
|
|
654 | =over 4 |
|
|
655 | |
|
|
656 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
657 | |
|
|
658 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
659 | model it chooses. |
|
|
660 | |
|
|
661 | =item C<PERL_ANYEVENT_MODEL> |
|
|
662 | |
|
|
663 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
664 | autodetection and -probing kicks in. It must be a string consisting |
|
|
665 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
666 | and the resulting module name is loaded and if the load was successful, |
|
|
667 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
668 | autodetection and -probing. |
|
|
669 | |
|
|
670 | This functionality might change in future versions. |
|
|
671 | |
|
|
672 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
673 | could start your program like this: |
|
|
674 | |
|
|
675 | PERL_ANYEVENT_MODEL=Perl perl ... |
117 | |
676 | |
118 | =back |
677 | =back |
119 | |
678 | |
120 | =head1 EXAMPLE |
679 | =head1 EXAMPLE PROGRAM |
121 | |
680 | |
122 | The following program uses an io watcher to read data from stdin, a timer |
681 | The following program uses an IO watcher to read data from STDIN, a timer |
123 | to display a message once per second, and a condvar to exit the program |
682 | to display a message once per second, and a condition variable to quit the |
124 | when the user enters quit: |
683 | program when the user enters quit: |
125 | |
684 | |
126 | use AnyEvent; |
685 | use AnyEvent; |
127 | |
686 | |
128 | my $cv = AnyEvent->condvar; |
687 | my $cv = AnyEvent->condvar; |
129 | |
688 | |
130 | my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
689 | my $io_watcher = AnyEvent->io ( |
|
|
690 | fh => \*STDIN, |
|
|
691 | poll => 'r', |
|
|
692 | cb => sub { |
131 | warn "io event <$_[0]>\n"; # will always output <r> |
693 | warn "io event <$_[0]>\n"; # will always output <r> |
132 | chomp (my $input = <STDIN>); # read a line |
694 | chomp (my $input = <STDIN>); # read a line |
133 | warn "read: $input\n"; # output what has been read |
695 | warn "read: $input\n"; # output what has been read |
134 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
696 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
|
|
697 | }, |
135 | }); |
698 | ); |
136 | |
699 | |
137 | my $time_watcher; # can only be used once |
700 | my $time_watcher; # can only be used once |
138 | |
701 | |
139 | sub new_timer { |
702 | sub new_timer { |
140 | $timer = AnyEvent->timer (after => 1, cb => sub { |
703 | $timer = AnyEvent->timer (after => 1, cb => sub { |
… | |
… | |
183 | connect $txn->{fh}, ... |
746 | connect $txn->{fh}, ... |
184 | and !$!{EWOULDBLOCK} |
747 | and !$!{EWOULDBLOCK} |
185 | and !$!{EINPROGRESS} |
748 | and !$!{EINPROGRESS} |
186 | and Carp::croak "unable to connect: $!\n"; |
749 | and Carp::croak "unable to connect: $!\n"; |
187 | |
750 | |
188 | Then it creates a write-watcher which gets called wehnever an error occurs |
751 | Then it creates a write-watcher which gets called whenever an error occurs |
189 | or the connection succeeds: |
752 | or the connection succeeds: |
190 | |
753 | |
191 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'w', cb => sub { $txn->fh_ready_w }); |
754 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'w', cb => sub { $txn->fh_ready_w }); |
192 | |
755 | |
193 | And returns this transaction object. The C<fh_ready_w> callback gets |
756 | And returns this transaction object. The C<fh_ready_w> callback gets |
… | |
… | |
210 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
773 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
211 | |
774 | |
212 | if (end-of-file or data complete) { |
775 | if (end-of-file or data complete) { |
213 | $txn->{result} = $txn->{buf}; |
776 | $txn->{result} = $txn->{buf}; |
214 | $txn->{finished}->broadcast; |
777 | $txn->{finished}->broadcast; |
|
|
778 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
215 | } |
779 | } |
216 | |
780 | |
217 | The C<result> method, finally, just waits for the finished signal (if the |
781 | The C<result> method, finally, just waits for the finished signal (if the |
218 | request was already finished, it doesn't wait, of course, and returns the |
782 | request was already finished, it doesn't wait, of course, and returns the |
219 | data: |
783 | data: |
220 | |
784 | |
221 | $txn->{finished}->wait; |
785 | $txn->{finished}->wait; |
222 | return $txn->{buf}; |
786 | return $txn->{result}; |
223 | |
787 | |
224 | The actual code goes further and collects all errors (C<die>s, exceptions) |
788 | The actual code goes further and collects all errors (C<die>s, exceptions) |
225 | that occured during request processing. The C<result> method detects |
789 | that occured during request processing. The C<result> method detects |
226 | wether an exception as thrown (it is stored inside the $txn object) |
790 | whether an exception as thrown (it is stored inside the $txn object) |
227 | and just throws the exception, which means connection errors and other |
791 | and just throws the exception, which means connection errors and other |
228 | problems get reported tot he code that tries to use the result, not in a |
792 | problems get reported tot he code that tries to use the result, not in a |
229 | random callback. |
793 | random callback. |
230 | |
794 | |
231 | All of this enables the following usage styles: |
795 | All of this enables the following usage styles: |
232 | |
796 | |
233 | 1. Blocking: |
797 | 1. Blocking: |
234 | |
798 | |
235 | my $data = $fcp->client_get ($url); |
799 | my $data = $fcp->client_get ($url); |
236 | |
800 | |
237 | 2. Blocking, but parallelizing: |
801 | 2. Blocking, but running in parallel: |
238 | |
802 | |
239 | my @datas = map $_->result, |
803 | my @datas = map $_->result, |
240 | map $fcp->txn_client_get ($_), |
804 | map $fcp->txn_client_get ($_), |
241 | @urls; |
805 | @urls; |
242 | |
806 | |
243 | Both blocking examples work without the module user having to know |
807 | Both blocking examples work without the module user having to know |
244 | anything about events. |
808 | anything about events. |
245 | |
809 | |
246 | 3a. Event-based in a main program, using any support Event module: |
810 | 3a. Event-based in a main program, using any supported event module: |
247 | |
811 | |
248 | use Event; |
812 | use EV; |
249 | |
813 | |
250 | $fcp->txn_client_get ($url)->cb (sub { |
814 | $fcp->txn_client_get ($url)->cb (sub { |
251 | my $txn = shift; |
815 | my $txn = shift; |
252 | my $data = $txn->result; |
816 | my $data = $txn->result; |
253 | ... |
817 | ... |
254 | }); |
818 | }); |
255 | |
819 | |
256 | Event::loop; |
820 | EV::loop; |
257 | |
821 | |
258 | 3b. The module user could use AnyEvent, too: |
822 | 3b. The module user could use AnyEvent, too: |
259 | |
823 | |
260 | use AnyEvent; |
824 | use AnyEvent; |
261 | |
825 | |
… | |
… | |
266 | $quit->broadcast; |
830 | $quit->broadcast; |
267 | }); |
831 | }); |
268 | |
832 | |
269 | $quit->wait; |
833 | $quit->wait; |
270 | |
834 | |
|
|
835 | =head1 FORK |
|
|
836 | |
|
|
837 | Most event libraries are not fork-safe. The ones who are usually are |
|
|
838 | because they are so inefficient. Only L<EV> is fully fork-aware. |
|
|
839 | |
|
|
840 | If you have to fork, you must either do so I<before> creating your first |
|
|
841 | watcher OR you must not use AnyEvent at all in the child. |
|
|
842 | |
|
|
843 | =head1 SECURITY CONSIDERATIONS |
|
|
844 | |
|
|
845 | AnyEvent can be forced to load any event model via |
|
|
846 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to |
|
|
847 | execute arbitrary code or directly gain access, it can easily be used to |
|
|
848 | make the program hang or malfunction in subtle ways, as AnyEvent watchers |
|
|
849 | will not be active when the program uses a different event model than |
|
|
850 | specified in the variable. |
|
|
851 | |
|
|
852 | You can make AnyEvent completely ignore this variable by deleting it |
|
|
853 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
|
|
854 | |
|
|
855 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
|
|
856 | |
|
|
857 | use AnyEvent; |
|
|
858 | |
271 | =head1 SEE ALSO |
859 | =head1 SEE ALSO |
272 | |
860 | |
273 | Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>. |
861 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
|
|
862 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
|
|
863 | L<Event::Lib>. |
274 | |
864 | |
|
|
865 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
275 | Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>. |
866 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
|
|
867 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>. |
276 | |
868 | |
277 | Nontrivial usage example: L<Net::FCP>. |
869 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
278 | |
870 | |
279 | =head1 |
871 | =head1 AUTHOR |
|
|
872 | |
|
|
873 | Marc Lehmann <schmorp@schmorp.de> |
|
|
874 | http://home.schmorp.de/ |
280 | |
875 | |
281 | =cut |
876 | =cut |
282 | |
877 | |
283 | 1 |
878 | 1 |
284 | |
879 | |