ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/cvsroot/Coro/Coro.pm
(Generate patch)

Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.237 by root, Sat Nov 22 16:37:11 2008 UTC vs.
Revision 1.248 by root, Mon Dec 15 15:03:31 2008 UTC

1=head1 NAME 1=head1 NAME
2 2
3Coro - real threads in perl 3Coro - the only real threads in perl
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use Coro; 7 use Coro;
8 8
11 print "2\n"; 11 print "2\n";
12 cede; # yield back to main 12 cede; # yield back to main
13 print "4\n"; 13 print "4\n";
14 }; 14 };
15 print "1\n"; 15 print "1\n";
16 cede; # yield to coroutine 16 cede; # yield to coro
17 print "3\n"; 17 print "3\n";
18 cede; # and again 18 cede; # and again
19 19
20 # use locking 20 # use locking
21 use Coro::Semaphore; 21 use Coro::Semaphore;
29=head1 DESCRIPTION 29=head1 DESCRIPTION
30 30
31For a tutorial-style introduction, please read the L<Coro::Intro> 31For a tutorial-style introduction, please read the L<Coro::Intro>
32manpage. This manpage mainly contains reference information. 32manpage. This manpage mainly contains reference information.
33 33
34This module collection manages coroutines, that is, cooperative 34This module collection manages continuations in general, most often in
35threads. Coroutines are similar to kernel threads but don't (in general) 35the form of cooperative threads (also called coros, or simply "coro"
36in the documentation). They are similar to kernel threads but don't (in
36run in parallel at the same time even on SMP machines. The specific flavor 37general) run in parallel at the same time even on SMP machines. The
37of coroutine used in this module also guarantees you that it will not 38specific flavor of thread offered by this module also guarantees you that
38switch between coroutines unless necessary, at easily-identified points 39it will not switch between threads unless necessary, at easily-identified
39in your program, so locking and parallel access are rarely an issue, 40points in your program, so locking and parallel access are rarely an
40making coroutine programming much safer and easier than using other thread 41issue, making thread programming much safer and easier than using other
41models. 42thread models.
42 43
43Unlike the so-called "Perl threads" (which are not actually real threads 44Unlike the so-called "Perl threads" (which are not actually real threads
44but only the windows process emulation ported to unix), Coro provides a 45but only the windows process emulation ported to unix), Coro provides a
45full shared address space, which makes communication between coroutines 46full shared address space, which makes communication between threads
46very easy. And coroutines are fast, too: disabling the Windows process 47very easy. And threads are fast, too: disabling the Windows process
47emulation code in your perl and using Coro can easily result in a two to 48emulation code in your perl and using Coro can easily result in a two to
48four times speed increase for your programs. 49four times speed increase for your programs.
49 50
50Coro achieves that by supporting multiple running interpreters that share 51Coro achieves that by supporting multiple running interpreters that share
51data, which is especially useful to code pseudo-parallel processes and 52data, which is especially useful to code pseudo-parallel processes and
52for event-based programming, such as multiple HTTP-GET requests running 53for event-based programming, such as multiple HTTP-GET requests running
53concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro 54concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro
54into an event-based environment. 55into an event-based environment.
55 56
56In this module, a coroutines is defined as "callchain + lexical variables 57In this module, a thread is defined as "callchain + lexical variables +
57+ @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own 58@_ + $_ + $@ + $/ + C stack), that is, a thread has its own callchain,
58callchain, its own set of lexicals and its own set of perls most important 59its own set of lexicals and its own set of perls most important global
59global variables (see L<Coro::State> for more configuration and background 60variables (see L<Coro::State> for more configuration and background info).
60info).
61 61
62See also the C<SEE ALSO> section at the end of this document - the Coro 62See also the C<SEE ALSO> section at the end of this document - the Coro
63module family is quite large. 63module family is quite large.
64 64
65=cut 65=cut
67package Coro; 67package Coro;
68 68
69use strict qw(vars subs); 69use strict qw(vars subs);
70no warnings "uninitialized"; 70no warnings "uninitialized";
71 71
72use Guard ();
73
72use Coro::State; 74use Coro::State;
73 75
74use base qw(Coro::State Exporter); 76use base qw(Coro::State Exporter);
75 77
76our $idle; # idle handler 78our $idle; # idle handler
77our $main; # main coroutine 79our $main; # main coro
78our $current; # current coroutine 80our $current; # current coro
79 81
80our $VERSION = "5.0"; 82our $VERSION = 5.13;
81 83
82our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 84our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
83our %EXPORT_TAGS = ( 85our %EXPORT_TAGS = (
84 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 86 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
85); 87);
89 91
90=over 4 92=over 4
91 93
92=item $Coro::main 94=item $Coro::main
93 95
94This variable stores the coroutine object that represents the main 96This variable stores the Coro object that represents the main
95program. While you cna C<ready> it and do most other things you can do to 97program. While you cna C<ready> it and do most other things you can do to
96coroutines, it is mainly useful to compare again C<$Coro::current>, to see 98coro, it is mainly useful to compare again C<$Coro::current>, to see
97whether you are running in the main program or not. 99whether you are running in the main program or not.
98 100
99=cut 101=cut
100 102
101# $main is now being initialised by Coro::State 103# $main is now being initialised by Coro::State
102 104
103=item $Coro::current 105=item $Coro::current
104 106
105The coroutine object representing the current coroutine (the last 107The Coro object representing the current coro (the last
106coroutine that the Coro scheduler switched to). The initial value is 108coro that the Coro scheduler switched to). The initial value is
107C<$Coro::main> (of course). 109C<$Coro::main> (of course).
108 110
109This variable is B<strictly> I<read-only>. You can take copies of the 111This variable is B<strictly> I<read-only>. You can take copies of the
110value stored in it and use it as any other coroutine object, but you must 112value stored in it and use it as any other Coro object, but you must
111not otherwise modify the variable itself. 113not otherwise modify the variable itself.
112 114
113=cut 115=cut
114 116
115sub current() { $current } # [DEPRECATED] 117sub current() { $current } # [DEPRECATED]
116 118
117=item $Coro::idle 119=item $Coro::idle
118 120
119This variable is mainly useful to integrate Coro into event loops. It is 121This variable is mainly useful to integrate Coro into event loops. It is
120usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is 122usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is
121pretty low-level functionality. 123pretty low-level functionality.
122 124
123This variable stores a callback that is called whenever the scheduler 125This variable stores either a Coro object or a callback.
126
127If it is a callback, the it is called whenever the scheduler finds no
124finds no ready coroutines to run. The default implementation prints 128ready coros to run. The default implementation prints "FATAL:
125"FATAL: deadlock detected" and exits, because the program has no other way 129deadlock detected" and exits, because the program has no other way to
126to continue. 130continue.
127 131
132If it is a coro object, then this object will be readied (without
133invoking any ready hooks, however) when the scheduler finds no other ready
134coros to run.
135
128This hook is overwritten by modules such as C<Coro::Timer> and 136This hook is overwritten by modules such as C<Coro::EV> and
129C<Coro::AnyEvent> to wait on an external event that hopefully wake up a 137C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
130coroutine so the scheduler can run it. 138coro so the scheduler can run it.
131 139
132Note that the callback I<must not>, under any circumstances, block 140Note that the callback I<must not>, under any circumstances, block
133the current coroutine. Normally, this is achieved by having an "idle 141the current coro. Normally, this is achieved by having an "idle
134coroutine" that calls the event loop and then blocks again, and then 142coro" that calls the event loop and then blocks again, and then
135readying that coroutine in the idle handler. 143readying that coro in the idle handler, or by simply placing the idle
144coro in this variable.
136 145
137See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this 146See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
138technique. 147technique.
139 148
140Please note that if your callback recursively invokes perl (e.g. for event 149Please note that if your callback recursively invokes perl (e.g. for event
145$idle = sub { 154$idle = sub {
146 require Carp; 155 require Carp;
147 Carp::croak ("FATAL: deadlock detected"); 156 Carp::croak ("FATAL: deadlock detected");
148}; 157};
149 158
150# this coroutine is necessary because a coroutine 159# this coro is necessary because a coro
151# cannot destroy itself. 160# cannot destroy itself.
152our @destroy; 161our @destroy;
153our $manager; 162our $manager;
154 163
155$manager = new Coro sub { 164$manager = new Coro sub {
156 while () { 165 while () {
157 Coro::_cancel shift @destroy 166 Coro::State::cancel shift @destroy
158 while @destroy; 167 while @destroy;
159 168
160 &schedule; 169 &schedule;
161 } 170 }
162}; 171};
163$manager->{desc} = "[coro manager]"; 172$manager->{desc} = "[coro manager]";
164$manager->prio (PRIO_MAX); 173$manager->prio (PRIO_MAX);
165 174
166=back 175=back
167 176
168=head1 SIMPLE COROUTINE CREATION 177=head1 SIMPLE CORO CREATION
169 178
170=over 4 179=over 4
171 180
172=item async { ... } [@args...] 181=item async { ... } [@args...]
173 182
174Create a new coroutine and return it's coroutine object (usually 183Create a new coro and return its Coro object (usually
175unused). The coroutine will be put into the ready queue, so 184unused). The coro will be put into the ready queue, so
176it will start running automatically on the next scheduler run. 185it will start running automatically on the next scheduler run.
177 186
178The first argument is a codeblock/closure that should be executed in the 187The first argument is a codeblock/closure that should be executed in the
179coroutine. When it returns argument returns the coroutine is automatically 188coro. When it returns argument returns the coro is automatically
180terminated. 189terminated.
181 190
182The remaining arguments are passed as arguments to the closure. 191The remaining arguments are passed as arguments to the closure.
183 192
184See the C<Coro::State::new> constructor for info about the coroutine 193See the C<Coro::State::new> constructor for info about the coro
185environment in which coroutines are executed. 194environment in which coro are executed.
186 195
187Calling C<exit> in a coroutine will do the same as calling exit outside 196Calling C<exit> in a coro will do the same as calling exit outside
188the coroutine. Likewise, when the coroutine dies, the program will exit, 197the coro. Likewise, when the coro dies, the program will exit,
189just as it would in the main program. 198just as it would in the main program.
190 199
191If you do not want that, you can provide a default C<die> handler, or 200If you do not want that, you can provide a default C<die> handler, or
192simply avoid dieing (by use of C<eval>). 201simply avoid dieing (by use of C<eval>).
193 202
194Example: Create a new coroutine that just prints its arguments. 203Example: Create a new coro that just prints its arguments.
195 204
196 async { 205 async {
197 print "@_\n"; 206 print "@_\n";
198 } 1,2,3,4; 207 } 1,2,3,4;
199 208
205 $coro 214 $coro
206} 215}
207 216
208=item async_pool { ... } [@args...] 217=item async_pool { ... } [@args...]
209 218
210Similar to C<async>, but uses a coroutine pool, so you should not call 219Similar to C<async>, but uses a coro pool, so you should not call
211terminate or join on it (although you are allowed to), and you get a 220terminate or join on it (although you are allowed to), and you get a
212coroutine that might have executed other code already (which can be good 221coro that might have executed other code already (which can be good
213or bad :). 222or bad :).
214 223
215On the plus side, this function is about twice as fast as creating (and 224On the plus side, this function is about twice as fast as creating (and
216destroying) a completely new coroutine, so if you need a lot of generic 225destroying) a completely new coro, so if you need a lot of generic
217coroutines in quick successsion, use C<async_pool>, not C<async>. 226coros in quick successsion, use C<async_pool>, not C<async>.
218 227
219The code block is executed in an C<eval> context and a warning will be 228The code block is executed in an C<eval> context and a warning will be
220issued in case of an exception instead of terminating the program, as 229issued in case of an exception instead of terminating the program, as
221C<async> does. As the coroutine is being reused, stuff like C<on_destroy> 230C<async> does. As the coro is being reused, stuff like C<on_destroy>
222will not work in the expected way, unless you call terminate or cancel, 231will not work in the expected way, unless you call terminate or cancel,
223which somehow defeats the purpose of pooling (but is fine in the 232which somehow defeats the purpose of pooling (but is fine in the
224exceptional case). 233exceptional case).
225 234
226The priority will be reset to C<0> after each run, tracing will be 235The priority will be reset to C<0> after each run, tracing will be
227disabled, the description will be reset and the default output filehandle 236disabled, the description will be reset and the default output filehandle
228gets restored, so you can change all these. Otherwise the coroutine will 237gets restored, so you can change all these. Otherwise the coro will
229be re-used "as-is": most notably if you change other per-coroutine global 238be re-used "as-is": most notably if you change other per-coro global
230stuff such as C<$/> you I<must needs> revert that change, which is most 239stuff such as C<$/> you I<must needs> revert that change, which is most
231simply done by using local as in: C<< local $/ >>. 240simply done by using local as in: C<< local $/ >>.
232 241
233The idle pool size is limited to C<8> idle coroutines (this can be 242The idle pool size is limited to C<8> idle coros (this can be
234adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle 243adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
235coros as required. 244coros as required.
236 245
237If you are concerned about pooled coroutines growing a lot because a 246If you are concerned about pooled coros growing a lot because a
238single C<async_pool> used a lot of stackspace you can e.g. C<async_pool 247single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
239{ terminate }> once per second or so to slowly replenish the pool. In 248{ terminate }> once per second or so to slowly replenish the pool. In
240addition to that, when the stacks used by a handler grows larger than 32kb 249addition to that, when the stacks used by a handler grows larger than 32kb
241(adjustable via $Coro::POOL_RSS) it will also be destroyed. 250(adjustable via $Coro::POOL_RSS) it will also be destroyed.
242 251
259=back 268=back
260 269
261=head1 STATIC METHODS 270=head1 STATIC METHODS
262 271
263Static methods are actually functions that implicitly operate on the 272Static methods are actually functions that implicitly operate on the
264current coroutine. 273current coro.
265 274
266=over 4 275=over 4
267 276
268=item schedule 277=item schedule
269 278
270Calls the scheduler. The scheduler will find the next coroutine that is 279Calls the scheduler. The scheduler will find the next coro that is
271to be run from the ready queue and switches to it. The next coroutine 280to be run from the ready queue and switches to it. The next coro
272to be run is simply the one with the highest priority that is longest 281to be run is simply the one with the highest priority that is longest
273in its ready queue. If there is no coroutine ready, it will clal the 282in its ready queue. If there is no coro ready, it will clal the
274C<$Coro::idle> hook. 283C<$Coro::idle> hook.
275 284
276Please note that the current coroutine will I<not> be put into the ready 285Please note that the current coro will I<not> be put into the ready
277queue, so calling this function usually means you will never be called 286queue, so calling this function usually means you will never be called
278again unless something else (e.g. an event handler) calls C<< ->ready >>, 287again unless something else (e.g. an event handler) calls C<< ->ready >>,
279thus waking you up. 288thus waking you up.
280 289
281This makes C<schedule> I<the> generic method to use to block the current 290This makes C<schedule> I<the> generic method to use to block the current
282coroutine and wait for events: first you remember the current coroutine in 291coro and wait for events: first you remember the current coro in
283a variable, then arrange for some callback of yours to call C<< ->ready 292a variable, then arrange for some callback of yours to call C<< ->ready
284>> on that once some event happens, and last you call C<schedule> to put 293>> on that once some event happens, and last you call C<schedule> to put
285yourself to sleep. Note that a lot of things can wake your coroutine up, 294yourself to sleep. Note that a lot of things can wake your coro up,
286so you need to check whether the event indeed happened, e.g. by storing the 295so you need to check whether the event indeed happened, e.g. by storing the
287status in a variable. 296status in a variable.
288 297
289See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. 298See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks.
290 299
291=item cede 300=item cede
292 301
293"Cede" to other coroutines. This function puts the current coroutine into 302"Cede" to other coros. This function puts the current coro into
294the ready queue and calls C<schedule>, which has the effect of giving 303the ready queue and calls C<schedule>, which has the effect of giving
295up the current "timeslice" to other coroutines of the same or higher 304up the current "timeslice" to other coros of the same or higher
296priority. Once your coroutine gets its turn again it will automatically be 305priority. Once your coro gets its turn again it will automatically be
297resumed. 306resumed.
298 307
299This function is often called C<yield> in other languages. 308This function is often called C<yield> in other languages.
300 309
301=item Coro::cede_notself 310=item Coro::cede_notself
302 311
303Works like cede, but is not exported by default and will cede to I<any> 312Works like cede, but is not exported by default and will cede to I<any>
304coroutine, regardless of priority. This is useful sometimes to ensure 313coro, regardless of priority. This is useful sometimes to ensure
305progress is made. 314progress is made.
306 315
307=item terminate [arg...] 316=item terminate [arg...]
308 317
309Terminates the current coroutine with the given status values (see L<cancel>). 318Terminates the current coro with the given status values (see L<cancel>).
319
320=item Coro::on_enter BLOCK, Coro::on_leave BLOCK
321
322These function install enter and leave winders in the current scope. The
323enter block will be executed when on_enter is called and whenever the
324current coro is re-entered by the scheduler, while the leave block is
325executed whenever the current coro is blocked by the scheduler, and
326also when the containing scope is exited (by whatever means, be it exit,
327die, last etc.).
328
329I<Neither invoking the scheduler, nor exceptions, are allowed within those
330BLOCKs>. That means: do not even think about calling C<die> without an
331eval, and do not even think of entering the scheduler in any way.
332
333Since both BLOCKs are tied to the current scope, they will automatically
334be removed when the current scope exits.
335
336These functions implement the same concept as C<dynamic-wind> in scheme
337does, and are useful when you want to localise some resource to a specific
338coro.
339
340They slow down coro switching considerably for coros that use
341them (But coro switching is still reasonably fast if the handlers are
342fast).
343
344These functions are best understood by an example: The following function
345will change the current timezone to "Antarctica/South_Pole", which
346requires a call to C<tzset>, but by using C<on_enter> and C<on_leave>,
347which remember/change the current timezone and restore the previous
348value, respectively, the timezone is only changes for the coro that
349installed those handlers.
350
351 use POSIX qw(tzset);
352
353 async {
354 my $old_tz; # store outside TZ value here
355
356 Coro::on_enter {
357 $old_tz = $ENV{TZ}; # remember the old value
358
359 $ENV{TZ} = "Antarctica/South_Pole";
360 tzset; # enable new value
361 };
362
363 Coro::on_leave {
364 $ENV{TZ} = $old_tz;
365 tzset; # restore old value
366 };
367
368 # at this place, the timezone is Antarctica/South_Pole,
369 # without disturbing the TZ of any other coro.
370 };
371
372This can be used to localise about any resource (locale, uid, current
373working directory etc.) to a block, despite the existance of other
374coros.
310 375
311=item killall 376=item killall
312 377
313Kills/terminates/cancels all coroutines except the currently running 378Kills/terminates/cancels all coros except the currently running one.
314one. This is useful after a fork, either in the child or the parent, as
315usually only one of them should inherit the running coroutines.
316 379
317Note that while this will try to free some of the main programs resources, 380Note that while this will try to free some of the main interpreter
381resources if the calling coro isn't the main coro, but one
318you cannot free all of them, so if a coroutine that is not the main 382cannot free all of them, so if a coro that is not the main coro
319program calls this function, there will be some one-time resource leak. 383calls this function, there will be some one-time resource leak.
320 384
321=cut 385=cut
322 386
323sub killall { 387sub killall {
324 for (Coro::State::list) { 388 for (Coro::State::list) {
327 } 391 }
328} 392}
329 393
330=back 394=back
331 395
332=head1 COROUTINE OBJECT METHODS 396=head1 CORO OBJECT METHODS
333 397
334These are the methods you can call on coroutine objects (or to create 398These are the methods you can call on coro objects (or to create
335them). 399them).
336 400
337=over 4 401=over 4
338 402
339=item new Coro \&sub [, @args...] 403=item new Coro \&sub [, @args...]
340 404
341Create a new coroutine and return it. When the sub returns, the coroutine 405Create a new coro and return it. When the sub returns, the coro
342automatically terminates as if C<terminate> with the returned values were 406automatically terminates as if C<terminate> with the returned values were
343called. To make the coroutine run you must first put it into the ready 407called. To make the coro run you must first put it into the ready
344queue by calling the ready method. 408queue by calling the ready method.
345 409
346See C<async> and C<Coro::State::new> for additional info about the 410See C<async> and C<Coro::State::new> for additional info about the
347coroutine environment. 411coro environment.
348 412
349=cut 413=cut
350 414
351sub _terminate { 415sub _coro_run {
352 terminate &{+shift}; 416 terminate &{+shift};
353} 417}
354 418
355=item $success = $coroutine->ready 419=item $success = $coro->ready
356 420
357Put the given coroutine into the end of its ready queue (there is one 421Put the given coro into the end of its ready queue (there is one
358queue for each priority) and return true. If the coroutine is already in 422queue for each priority) and return true. If the coro is already in
359the ready queue, do nothing and return false. 423the ready queue, do nothing and return false.
360 424
361This ensures that the scheduler will resume this coroutine automatically 425This ensures that the scheduler will resume this coro automatically
362once all the coroutines of higher priority and all coroutines of the same 426once all the coro of higher priority and all coro of the same
363priority that were put into the ready queue earlier have been resumed. 427priority that were put into the ready queue earlier have been resumed.
364 428
365=item $is_ready = $coroutine->is_ready 429=item $is_ready = $coro->is_ready
366 430
367Return whether the coroutine is currently the ready queue or not, 431Returns true iff the Coro object is in the ready queue. Unless the Coro
432object gets destroyed, it will eventually be scheduled by the scheduler.
368 433
434=item $is_running = $coro->is_running
435
436Returns true iff the Coro object is currently running. Only one Coro object
437can ever be in the running state (but it currently is possible to have
438multiple running Coro::States).
439
440=item $is_suspended = $coro->is_suspended
441
442Returns true iff this Coro object has been suspended. Suspended Coros will
443not ever be scheduled.
444
369=item $coroutine->cancel (arg...) 445=item $coro->cancel (arg...)
370 446
371Terminates the given coroutine and makes it return the given arguments as 447Terminates the given Coro and makes it return the given arguments as
372status (default: the empty list). Never returns if the coroutine is the 448status (default: the empty list). Never returns if the Coro is the
373current coroutine. 449current Coro.
374 450
375=cut 451=cut
376 452
377sub cancel { 453sub cancel {
378 my $self = shift; 454 my $self = shift;
379 455
380 if ($current == $self) { 456 if ($current == $self) {
381 terminate @_; 457 terminate @_;
382 } else { 458 } else {
383 $self->{_status} = [@_]; 459 $self->{_status} = [@_];
384 $self->_cancel; 460 Coro::State::cancel $self;
385 } 461 }
386} 462}
387 463
388=item $coroutine->schedule_to 464=item $coro->schedule_to
389 465
390Puts the current coroutine to sleep (like C<Coro::schedule>), but instead 466Puts the current coro to sleep (like C<Coro::schedule>), but instead
391of continuing with the next coro from the ready queue, always switch to 467of continuing with the next coro from the ready queue, always switch to
392the given coroutine object (regardless of priority etc.). The readyness 468the given coro object (regardless of priority etc.). The readyness
393state of that coroutine isn't changed. 469state of that coro isn't changed.
394 470
395This is an advanced method for special cases - I'd love to hear about any 471This is an advanced method for special cases - I'd love to hear about any
396uses for this one. 472uses for this one.
397 473
398=item $coroutine->cede_to 474=item $coro->cede_to
399 475
400Like C<schedule_to>, but puts the current coroutine into the ready 476Like C<schedule_to>, but puts the current coro into the ready
401queue. This has the effect of temporarily switching to the given 477queue. This has the effect of temporarily switching to the given
402coroutine, and continuing some time later. 478coro, and continuing some time later.
403 479
404This is an advanced method for special cases - I'd love to hear about any 480This is an advanced method for special cases - I'd love to hear about any
405uses for this one. 481uses for this one.
406 482
407=item $coroutine->throw ([$scalar]) 483=item $coro->throw ([$scalar])
408 484
409If C<$throw> is specified and defined, it will be thrown as an exception 485If C<$throw> is specified and defined, it will be thrown as an exception
410inside the coroutine at the next convenient point in time. Otherwise 486inside the coro at the next convenient point in time. Otherwise
411clears the exception object. 487clears the exception object.
412 488
413Coro will check for the exception each time a schedule-like-function 489Coro will check for the exception each time a schedule-like-function
414returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down 490returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down
415>>, C<< Coro::Handle->readable >> and so on. Most of these functions 491>>, C<< Coro::Handle->readable >> and so on. Most of these functions
417 493
418The exception object will be thrown "as is" with the specified scalar in 494The exception object will be thrown "as is" with the specified scalar in
419C<$@>, i.e. if it is a string, no line number or newline will be appended 495C<$@>, i.e. if it is a string, no line number or newline will be appended
420(unlike with C<die>). 496(unlike with C<die>).
421 497
422This can be used as a softer means than C<cancel> to ask a coroutine to 498This can be used as a softer means than C<cancel> to ask a coro to
423end itself, although there is no guarantee that the exception will lead to 499end itself, although there is no guarantee that the exception will lead to
424termination, and if the exception isn't caught it might well end the whole 500termination, and if the exception isn't caught it might well end the whole
425program. 501program.
426 502
427You might also think of C<throw> as being the moral equivalent of 503You might also think of C<throw> as being the moral equivalent of
428C<kill>ing a coroutine with a signal (in this case, a scalar). 504C<kill>ing a coro with a signal (in this case, a scalar).
429 505
430=item $coroutine->join 506=item $coro->join
431 507
432Wait until the coroutine terminates and return any values given to the 508Wait until the coro terminates and return any values given to the
433C<terminate> or C<cancel> functions. C<join> can be called concurrently 509C<terminate> or C<cancel> functions. C<join> can be called concurrently
434from multiple coroutines, and all will be resumed and given the status 510from multiple coro, and all will be resumed and given the status
435return once the C<$coroutine> terminates. 511return once the C<$coro> terminates.
436 512
437=cut 513=cut
438 514
439sub join { 515sub join {
440 my $self = shift; 516 my $self = shift;
451 } 527 }
452 528
453 wantarray ? @{$self->{_status}} : $self->{_status}[0]; 529 wantarray ? @{$self->{_status}} : $self->{_status}[0];
454} 530}
455 531
456=item $coroutine->on_destroy (\&cb) 532=item $coro->on_destroy (\&cb)
457 533
458Registers a callback that is called when this coroutine gets destroyed, 534Registers a callback that is called when this coro gets destroyed,
459but before it is joined. The callback gets passed the terminate arguments, 535but before it is joined. The callback gets passed the terminate arguments,
460if any, and I<must not> die, under any circumstances. 536if any, and I<must not> die, under any circumstances.
461 537
462=cut 538=cut
463 539
465 my ($self, $cb) = @_; 541 my ($self, $cb) = @_;
466 542
467 push @{ $self->{_on_destroy} }, $cb; 543 push @{ $self->{_on_destroy} }, $cb;
468} 544}
469 545
470=item $oldprio = $coroutine->prio ($newprio) 546=item $oldprio = $coro->prio ($newprio)
471 547
472Sets (or gets, if the argument is missing) the priority of the 548Sets (or gets, if the argument is missing) the priority of the
473coroutine. Higher priority coroutines get run before lower priority 549coro. Higher priority coro get run before lower priority
474coroutines. Priorities are small signed integers (currently -4 .. +3), 550coro. Priorities are small signed integers (currently -4 .. +3),
475that you can refer to using PRIO_xxx constants (use the import tag :prio 551that you can refer to using PRIO_xxx constants (use the import tag :prio
476to get then): 552to get then):
477 553
478 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 554 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
479 3 > 1 > 0 > -1 > -3 > -4 555 3 > 1 > 0 > -1 > -3 > -4
480 556
481 # set priority to HIGH 557 # set priority to HIGH
482 current->prio(PRIO_HIGH); 558 current->prio (PRIO_HIGH);
483 559
484The idle coroutine ($Coro::idle) always has a lower priority than any 560The idle coro ($Coro::idle) always has a lower priority than any
485existing coroutine. 561existing coro.
486 562
487Changing the priority of the current coroutine will take effect immediately, 563Changing the priority of the current coro will take effect immediately,
488but changing the priority of coroutines in the ready queue (but not 564but changing the priority of coro in the ready queue (but not
489running) will only take effect after the next schedule (of that 565running) will only take effect after the next schedule (of that
490coroutine). This is a bug that will be fixed in some future version. 566coro). This is a bug that will be fixed in some future version.
491 567
492=item $newprio = $coroutine->nice ($change) 568=item $newprio = $coro->nice ($change)
493 569
494Similar to C<prio>, but subtract the given value from the priority (i.e. 570Similar to C<prio>, but subtract the given value from the priority (i.e.
495higher values mean lower priority, just as in unix). 571higher values mean lower priority, just as in unix).
496 572
497=item $olddesc = $coroutine->desc ($newdesc) 573=item $olddesc = $coro->desc ($newdesc)
498 574
499Sets (or gets in case the argument is missing) the description for this 575Sets (or gets in case the argument is missing) the description for this
500coroutine. This is just a free-form string you can associate with a 576coro. This is just a free-form string you can associate with a
501coroutine. 577coro.
502 578
503This method simply sets the C<< $coroutine->{desc} >> member to the given 579This method simply sets the C<< $coro->{desc} >> member to the given
504string. You can modify this member directly if you wish. 580string. You can modify this member directly if you wish.
505 581
506=cut 582=cut
507 583
508sub desc { 584sub desc {
522 598
523=over 4 599=over 4
524 600
525=item Coro::nready 601=item Coro::nready
526 602
527Returns the number of coroutines that are currently in the ready state, 603Returns the number of coro that are currently in the ready state,
528i.e. that can be switched to by calling C<schedule> directory or 604i.e. that can be switched to by calling C<schedule> directory or
529indirectly. The value C<0> means that the only runnable coroutine is the 605indirectly. The value C<0> means that the only runnable coro is the
530currently running one, so C<cede> would have no effect, and C<schedule> 606currently running one, so C<cede> would have no effect, and C<schedule>
531would cause a deadlock unless there is an idle handler that wakes up some 607would cause a deadlock unless there is an idle handler that wakes up some
532coroutines. 608coro.
533 609
534=item my $guard = Coro::guard { ... } 610=item my $guard = Coro::guard { ... }
535 611
536This creates and returns a guard object. Nothing happens until the object 612This function still exists, but is deprecated. Please use the
537gets destroyed, in which case the codeblock given as argument will be 613C<Guard::guard> function instead.
538executed. This is useful to free locks or other resources in case of a
539runtime error or when the coroutine gets canceled, as in both cases the
540guard block will be executed. The guard object supports only one method,
541C<< ->cancel >>, which will keep the codeblock from being executed.
542 614
543Example: set some flag and clear it again when the coroutine gets canceled
544or the function returns:
545
546 sub do_something {
547 my $guard = Coro::guard { $busy = 0 };
548 $busy = 1;
549
550 # do something that requires $busy to be true
551 }
552
553=cut 615=cut
554 616
555sub guard(&) { 617BEGIN { *guard = \&Guard::guard }
556 bless \(my $cb = $_[0]), "Coro::guard"
557}
558
559sub Coro::guard::cancel {
560 ${$_[0]} = sub { };
561}
562
563sub Coro::guard::DESTROY {
564 ${$_[0]}->();
565}
566
567 618
568=item unblock_sub { ... } 619=item unblock_sub { ... }
569 620
570This utility function takes a BLOCK or code reference and "unblocks" it, 621This utility function takes a BLOCK or code reference and "unblocks" it,
571returning a new coderef. Unblocking means that calling the new coderef 622returning a new coderef. Unblocking means that calling the new coderef
572will return immediately without blocking, returning nothing, while the 623will return immediately without blocking, returning nothing, while the
573original code ref will be called (with parameters) from within another 624original code ref will be called (with parameters) from within another
574coroutine. 625coro.
575 626
576The reason this function exists is that many event libraries (such as the 627The reason this function exists is that many event libraries (such as the
577venerable L<Event|Event> module) are not coroutine-safe (a weaker form 628venerable L<Event|Event> module) are not thread-safe (a weaker form
578of thread-safety). This means you must not block within event callbacks, 629of reentrancy). This means you must not block within event callbacks,
579otherwise you might suffer from crashes or worse. The only event library 630otherwise you might suffer from crashes or worse. The only event library
580currently known that is safe to use without C<unblock_sub> is L<EV>. 631currently known that is safe to use without C<unblock_sub> is L<EV>.
581 632
582This function allows your callbacks to block by executing them in another 633This function allows your callbacks to block by executing them in another
583coroutine where it is safe to block. One example where blocking is handy 634coro where it is safe to block. One example where blocking is handy
584is when you use the L<Coro::AIO|Coro::AIO> functions to save results to 635is when you use the L<Coro::AIO|Coro::AIO> functions to save results to
585disk, for example. 636disk, for example.
586 637
587In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when 638In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
588creating event callbacks that want to block. 639creating event callbacks that want to block.
589 640
590If your handler does not plan to block (e.g. simply sends a message to 641If your handler does not plan to block (e.g. simply sends a message to
591another coroutine, or puts some other coroutine into the ready queue), 642another coro, or puts some other coro into the ready queue), there is
592there is no reason to use C<unblock_sub>. 643no reason to use C<unblock_sub>.
593 644
594Note that you also need to use C<unblock_sub> for any other callbacks that 645Note that you also need to use C<unblock_sub> for any other callbacks that
595are indirectly executed by any C-based event loop. For example, when you 646are indirectly executed by any C-based event loop. For example, when you
596use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it 647use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
597provides callbacks that are the result of some event callback, then you 648provides callbacks that are the result of some event callback, then you
629 } 680 }
630} 681}
631 682
632=item $cb = Coro::rouse_cb 683=item $cb = Coro::rouse_cb
633 684
634Create and return a "rouse callback". That's a code reference that, when 685Create and return a "rouse callback". That's a code reference that,
635called, will save its arguments and notify the owner coroutine of the 686when called, will remember a copy of its arguments and notify the owner
636callback. 687coro of the callback.
637 688
638See the next function. 689See the next function.
639 690
640=item @args = Coro::rouse_wait [$cb] 691=item @args = Coro::rouse_wait [$cb]
641 692
642Wait for the specified rouse callback (or the last one tht was created in 693Wait for the specified rouse callback (or the last one that was created in
643this coroutine). 694this coro).
644 695
645As soon as the callback is invoked (or when the calback was invoked before 696As soon as the callback is invoked (or when the callback was invoked
646C<rouse_wait>), it will return a copy of the arguments originally passed 697before C<rouse_wait>), it will return the arguments originally passed to
647to the rouse callback. 698the rouse callback.
648 699
649See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. 700See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example.
650 701
651=back 702=back
652 703
654 705
6551; 7061;
656 707
657=head1 HOW TO WAIT FOR A CALLBACK 708=head1 HOW TO WAIT FOR A CALLBACK
658 709
659It is very common for a coroutine to wait for some callback to be 710It is very common for a coro to wait for some callback to be
660called. This occurs naturally when you use coroutines in an otherwise 711called. This occurs naturally when you use coro in an otherwise
661event-based program, or when you use event-based libraries. 712event-based program, or when you use event-based libraries.
662 713
663These typically register a callback for some event, and call that callback 714These typically register a callback for some event, and call that callback
664when the event occured. In a coroutine, however, you typically want to 715when the event occured. In a coro, however, you typically want to
665just wait for the event, simplyifying things. 716just wait for the event, simplyifying things.
666 717
667For example C<< AnyEvent->child >> registers a callback to be called when 718For example C<< AnyEvent->child >> registers a callback to be called when
668a specific child has exited: 719a specific child has exited:
669 720
670 my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); 721 my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... });
671 722
672But from withina coroutine, you often just want to write this: 723But from within a coro, you often just want to write this:
673 724
674 my $status = wait_for_child $pid; 725 my $status = wait_for_child $pid;
675 726
676Coro offers two functions specifically designed to make this easy, 727Coro offers two functions specifically designed to make this easy,
677C<Coro::rouse_cb> and C<Coro::rouse_wait>. 728C<Coro::rouse_cb> and C<Coro::rouse_wait>.
678 729
679The first function, C<rouse_cb>, generates and returns a callback that, 730The first function, C<rouse_cb>, generates and returns a callback that,
680when invoked, will save it's arguments and notify the coroutine that 731when invoked, will save its arguments and notify the coro that
681created the callback. 732created the callback.
682 733
683The second function, C<rouse_wait>, waits for the callback to be called 734The second function, C<rouse_wait>, waits for the callback to be called
684(by calling C<schedule> to go to sleep) and returns the arguments 735(by calling C<schedule> to go to sleep) and returns the arguments
685originally passed to the callback. 736originally passed to the callback.
700you can roll your own, using C<schedule>: 751you can roll your own, using C<schedule>:
701 752
702 sub wait_for_child($) { 753 sub wait_for_child($) {
703 my ($pid) = @_; 754 my ($pid) = @_;
704 755
705 # store the current coroutine in $current, 756 # store the current coro in $current,
706 # and provide result variables for the closure passed to ->child 757 # and provide result variables for the closure passed to ->child
707 my $current = $Coro::current; 758 my $current = $Coro::current;
708 my ($done, $rstatus); 759 my ($done, $rstatus);
709 760
710 # pass a closure to ->child 761 # pass a closure to ->child
726 777
727=item fork with pthread backend 778=item fork with pthread backend
728 779
729When Coro is compiled using the pthread backend (which isn't recommended 780When Coro is compiled using the pthread backend (which isn't recommended
730but required on many BSDs as their libcs are completely broken), then 781but required on many BSDs as their libcs are completely broken), then
731coroutines will not survive a fork. There is no known workaround except to 782coro will not survive a fork. There is no known workaround except to
732fix your libc and use a saner backend. 783fix your libc and use a saner backend.
733 784
734=item perl process emulation ("threads") 785=item perl process emulation ("threads")
735 786
736This module is not perl-pseudo-thread-safe. You should only ever use this 787This module is not perl-pseudo-thread-safe. You should only ever use this
737module from the same thread (this requirement might be removed in the 788module from the first thread (this requirement might be removed in the
738future to allow per-thread schedulers, but Coro::State does not yet allow 789future to allow per-thread schedulers, but Coro::State does not yet allow
739this). I recommend disabling thread support and using processes, as having 790this). I recommend disabling thread support and using processes, as having
740the windows process emulation enabled under unix roughly halves perl 791the windows process emulation enabled under unix roughly halves perl
741performance, even when not used. 792performance, even when not used.
742 793
743=item coroutine switching not signal safe 794=item coro switching is not signal safe
744 795
745You must not switch to another coroutine from within a signal handler 796You must not switch to another coro from within a signal handler
746(only relevant with %SIG - most event libraries provide safe signals). 797(only relevant with %SIG - most event libraries provide safe signals).
747 798
748That means you I<MUST NOT> call any function that might "block" the 799That means you I<MUST NOT> call any function that might "block" the
749current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or 800current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
750anything that calls those. Everything else, including calling C<ready>, 801anything that calls those. Everything else, including calling C<ready>,
751works. 802works.
752 803
753=back 804=back
754 805
759 810
760Debugging: L<Coro::Debug>. 811Debugging: L<Coro::Debug>.
761 812
762Support/Utility: L<Coro::Specific>, L<Coro::Util>. 813Support/Utility: L<Coro::Specific>, L<Coro::Util>.
763 814
764Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, 815Locking and IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>,
765L<Coro::SemaphoreSet>, L<Coro::RWLock>. 816L<Coro::SemaphoreSet>, L<Coro::RWLock>.
766 817
767IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. 818I/O and Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
768 819
769Compatibility: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for 820Compatibility with other modules: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for
770a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, 821a better-working alternative), L<Coro::BDB>, L<Coro::Storable>,
771L<Coro::Select>. 822L<Coro::Select>.
772 823
773XS API: L<Coro::MakeMaker>. 824XS API: L<Coro::MakeMaker>.
774 825
775Low level Configuration, Coroutine Environment: L<Coro::State>. 826Low level Configuration, Thread Environment, Continuations: L<Coro::State>.
776 827
777=head1 AUTHOR 828=head1 AUTHOR
778 829
779 Marc Lehmann <schmorp@schmorp.de> 830 Marc Lehmann <schmorp@schmorp.de>
780 http://home.schmorp.de/ 831 http://home.schmorp.de/

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines