1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | Coro - coroutine process abstraction |
3 | Coro - the only real threads in perl |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
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26 | $locked = 1; |
26 | $locked = 1; |
27 | $lock->up; |
27 | $lock->up; |
28 | |
28 | |
29 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
30 | |
30 | |
31 | This module collection manages coroutines. Coroutines are similar to |
31 | For a tutorial-style introduction, please read the L<Coro::Intro> |
32 | threads but don't (in general) run in parallel at the same time even |
32 | manpage. This manpage mainly contains reference information. |
33 | on SMP machines. The specific flavor of coroutine used in this module |
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34 | also guarantees you that it will not switch between coroutines unless |
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35 | necessary, at easily-identified points in your program, so locking and |
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36 | parallel access are rarely an issue, making coroutine programming much |
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37 | safer and easier than threads programming. |
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38 | |
33 | |
39 | Unlike a normal perl program, however, coroutines allow you to have |
34 | This module collection manages continuations in general, most often |
40 | multiple running interpreters that share data, which is especially useful |
35 | in the form of cooperative threads (also called coroutines in the |
41 | to code pseudo-parallel processes and for event-based programming, such as |
36 | documentation). They are similar to kernel threads but don't (in general) |
42 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
37 | run in parallel at the same time even on SMP machines. The specific flavor |
43 | learn more. |
38 | of thread offered by this module also guarantees you that it will not |
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39 | switch between threads unless necessary, at easily-identified points in |
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40 | your program, so locking and parallel access are rarely an issue, making |
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41 | thread programming much safer and easier than using other thread models. |
44 | |
42 | |
45 | Coroutines are also useful because Perl has no support for threads (the so |
43 | Unlike the so-called "Perl threads" (which are not actually real threads |
46 | called "threads" that perl offers are nothing more than the (bad) process |
44 | but only the windows process emulation ported to unix), Coro provides a |
47 | emulation coming from the Windows platform: On standard operating systems |
45 | full shared address space, which makes communication between threads |
48 | they serve no purpose whatsoever, except by making your programs slow and |
46 | very easy. And threads are fast, too: disabling the Windows process |
49 | making them use a lot of memory. Best disable them when building perl, or |
47 | emulation code in your perl and using Coro can easily result in a two to |
50 | aks your software vendor/distributor to do it for you). |
48 | four times speed increase for your programs. |
51 | |
49 | |
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50 | Coro achieves that by supporting multiple running interpreters that share |
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51 | data, which is especially useful to code pseudo-parallel processes and |
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52 | for event-based programming, such as multiple HTTP-GET requests running |
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53 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
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54 | into an event-based environment. |
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55 | |
52 | In this module, coroutines are defined as "callchain + lexical variables + |
56 | In this module, a thread is defined as "callchain + lexical variables + |
53 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
57 | @_ + $_ + $@ + $/ + C stack), that is, a thread has its own callchain, |
54 | its own set of lexicals and its own set of perls most important global |
58 | its own set of lexicals and its own set of perls most important global |
55 | variables (see L<Coro::State> for more configuration). |
59 | variables (see L<Coro::State> for more configuration and background info). |
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60 | |
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61 | See also the C<SEE ALSO> section at the end of this document - the Coro |
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62 | module family is quite large. |
56 | |
63 | |
57 | =cut |
64 | =cut |
58 | |
65 | |
59 | package Coro; |
66 | package Coro; |
60 | |
67 | |
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67 | |
74 | |
68 | our $idle; # idle handler |
75 | our $idle; # idle handler |
69 | our $main; # main coroutine |
76 | our $main; # main coroutine |
70 | our $current; # current coroutine |
77 | our $current; # current coroutine |
71 | |
78 | |
72 | our $VERSION = "5.0"; |
79 | our $VERSION = 5.11; |
73 | |
80 | |
74 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
81 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
75 | our %EXPORT_TAGS = ( |
82 | our %EXPORT_TAGS = ( |
76 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
83 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
77 | ); |
84 | ); |
78 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
85 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
79 | |
86 | |
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87 | =head1 GLOBAL VARIABLES |
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88 | |
80 | =over 4 |
89 | =over 4 |
81 | |
90 | |
82 | =item $Coro::main |
91 | =item $Coro::main |
83 | |
92 | |
84 | This variable stores the coroutine object that represents the main |
93 | This variable stores the coroutine object that represents the main |
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105 | sub current() { $current } # [DEPRECATED] |
114 | sub current() { $current } # [DEPRECATED] |
106 | |
115 | |
107 | =item $Coro::idle |
116 | =item $Coro::idle |
108 | |
117 | |
109 | This variable is mainly useful to integrate Coro into event loops. It is |
118 | This variable is mainly useful to integrate Coro into event loops. It is |
110 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
119 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
111 | pretty low-level functionality. |
120 | pretty low-level functionality. |
112 | |
121 | |
113 | This variable stores a callback that is called whenever the scheduler |
122 | This variable stores either a coroutine or a callback. |
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123 | |
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124 | If it is a callback, the it is called whenever the scheduler finds no |
114 | finds no ready coroutines to run. The default implementation prints |
125 | ready coroutines to run. The default implementation prints "FATAL: |
115 | "FATAL: deadlock detected" and exits, because the program has no other way |
126 | deadlock detected" and exits, because the program has no other way to |
116 | to continue. |
127 | continue. |
117 | |
128 | |
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129 | If it is a coroutine object, then this object will be readied (without |
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130 | invoking any ready hooks, however) when the scheduler finds no other ready |
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131 | coroutines to run. |
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132 | |
118 | This hook is overwritten by modules such as C<Coro::Timer> and |
133 | This hook is overwritten by modules such as C<Coro::EV> and |
119 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
134 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
120 | coroutine so the scheduler can run it. |
135 | coroutine so the scheduler can run it. |
121 | |
136 | |
122 | Note that the callback I<must not>, under any circumstances, block |
137 | Note that the callback I<must not>, under any circumstances, block |
123 | the current coroutine. Normally, this is achieved by having an "idle |
138 | the current coroutine. Normally, this is achieved by having an "idle |
124 | coroutine" that calls the event loop and then blocks again, and then |
139 | coroutine" that calls the event loop and then blocks again, and then |
125 | readying that coroutine in the idle handler. |
140 | readying that coroutine in the idle handler, or by simply placing the idle |
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141 | coroutine in this variable. |
126 | |
142 | |
127 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
143 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
128 | technique. |
144 | technique. |
129 | |
145 | |
130 | Please note that if your callback recursively invokes perl (e.g. for event |
146 | Please note that if your callback recursively invokes perl (e.g. for event |
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153 | $manager->{desc} = "[coro manager]"; |
169 | $manager->{desc} = "[coro manager]"; |
154 | $manager->prio (PRIO_MAX); |
170 | $manager->prio (PRIO_MAX); |
155 | |
171 | |
156 | =back |
172 | =back |
157 | |
173 | |
158 | =head2 SIMPLE COROUTINE CREATION |
174 | =head1 SIMPLE COROUTINE CREATION |
159 | |
175 | |
160 | =over 4 |
176 | =over 4 |
161 | |
177 | |
162 | =item async { ... } [@args...] |
178 | =item async { ... } [@args...] |
163 | |
179 | |
164 | Create a new coroutine and return it's coroutine object (usually |
180 | Create a new coroutine and return its coroutine object (usually |
165 | unused). The coroutine will be put into the ready queue, so |
181 | unused). The coroutine will be put into the ready queue, so |
166 | it will start running automatically on the next scheduler run. |
182 | it will start running automatically on the next scheduler run. |
167 | |
183 | |
168 | The first argument is a codeblock/closure that should be executed in the |
184 | The first argument is a codeblock/closure that should be executed in the |
169 | coroutine. When it returns argument returns the coroutine is automatically |
185 | coroutine. When it returns argument returns the coroutine is automatically |
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246 | } |
262 | } |
247 | } |
263 | } |
248 | |
264 | |
249 | =back |
265 | =back |
250 | |
266 | |
251 | =head2 STATIC METHODS |
267 | =head1 STATIC METHODS |
252 | |
268 | |
253 | Static methods are actually functions that operate on the current coroutine. |
269 | Static methods are actually functions that implicitly operate on the |
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270 | current coroutine. |
254 | |
271 | |
255 | =over 4 |
272 | =over 4 |
256 | |
273 | |
257 | =item schedule |
274 | =item schedule |
258 | |
275 | |
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316 | } |
333 | } |
317 | } |
334 | } |
318 | |
335 | |
319 | =back |
336 | =back |
320 | |
337 | |
321 | =head2 COROUTINE METHODS |
338 | =head1 COROUTINE OBJECT METHODS |
322 | |
339 | |
323 | These are the methods you can call on coroutine objects (or to create |
340 | These are the methods you can call on coroutine objects (or to create |
324 | them). |
341 | them). |
325 | |
342 | |
326 | =over 4 |
343 | =over 4 |
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335 | See C<async> and C<Coro::State::new> for additional info about the |
352 | See C<async> and C<Coro::State::new> for additional info about the |
336 | coroutine environment. |
353 | coroutine environment. |
337 | |
354 | |
338 | =cut |
355 | =cut |
339 | |
356 | |
340 | sub _terminate { |
357 | sub _coro_run { |
341 | terminate &{+shift}; |
358 | terminate &{+shift}; |
342 | } |
359 | } |
343 | |
360 | |
344 | =item $success = $coroutine->ready |
361 | =item $success = $coroutine->ready |
345 | |
362 | |
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498 | my $old = $_[0]{desc}; |
515 | my $old = $_[0]{desc}; |
499 | $_[0]{desc} = $_[1] if @_ > 1; |
516 | $_[0]{desc} = $_[1] if @_ > 1; |
500 | $old; |
517 | $old; |
501 | } |
518 | } |
502 | |
519 | |
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520 | sub transfer { |
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521 | require Carp; |
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522 | Carp::croak ("You must not call ->transfer on Coro objects. Use Coro::State objects or the ->schedule_to method. Caught"); |
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523 | } |
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524 | |
503 | =back |
525 | =back |
504 | |
526 | |
505 | =head2 GLOBAL FUNCTIONS |
527 | =head1 GLOBAL FUNCTIONS |
506 | |
528 | |
507 | =over 4 |
529 | =over 4 |
508 | |
530 | |
509 | =item Coro::nready |
531 | =item Coro::nready |
510 | |
532 | |
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557 | original code ref will be called (with parameters) from within another |
579 | original code ref will be called (with parameters) from within another |
558 | coroutine. |
580 | coroutine. |
559 | |
581 | |
560 | The reason this function exists is that many event libraries (such as the |
582 | The reason this function exists is that many event libraries (such as the |
561 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
583 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
562 | of thread-safety). This means you must not block within event callbacks, |
584 | of reentrancy). This means you must not block within event callbacks, |
563 | otherwise you might suffer from crashes or worse. The only event library |
585 | otherwise you might suffer from crashes or worse. The only event library |
564 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
586 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
565 | |
587 | |
566 | This function allows your callbacks to block by executing them in another |
588 | This function allows your callbacks to block by executing them in another |
567 | coroutine where it is safe to block. One example where blocking is handy |
589 | coroutine where it is safe to block. One example where blocking is handy |
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613 | } |
635 | } |
614 | } |
636 | } |
615 | |
637 | |
616 | =item $cb = Coro::rouse_cb |
638 | =item $cb = Coro::rouse_cb |
617 | |
639 | |
618 | Create and return a "rouse callback". That's a code reference that, when |
640 | Create and return a "rouse callback". That's a code reference that, |
619 | called, will save its arguments and notify the owner coroutine of the |
641 | when called, will remember a copy of its arguments and notify the owner |
620 | callback. |
642 | coroutine of the callback. |
621 | |
643 | |
622 | See the next function. |
644 | See the next function. |
623 | |
645 | |
624 | =item @args = Coro::rouse_wait [$cb] |
646 | =item @args = Coro::rouse_wait [$cb] |
625 | |
647 | |
626 | Wait for the specified rouse callback (or the last one tht was created in |
648 | Wait for the specified rouse callback (or the last one that was created in |
627 | this coroutine). |
649 | this coroutine). |
628 | |
650 | |
629 | As soon as the callback is invoked (or when the calback was invoked before |
651 | As soon as the callback is invoked (or when the callback was invoked |
630 | C<rouse_wait>), it will return a copy of the arguments originally passed |
652 | before C<rouse_wait>), it will return the arguments originally passed to |
631 | to the rouse callback. |
653 | the rouse callback. |
632 | |
654 | |
633 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
655 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
634 | |
656 | |
635 | =back |
657 | =back |
636 | |
658 | |
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659 | |
681 | |
660 | Coro offers two functions specifically designed to make this easy, |
682 | Coro offers two functions specifically designed to make this easy, |
661 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
683 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
662 | |
684 | |
663 | The first function, C<rouse_cb>, generates and returns a callback that, |
685 | The first function, C<rouse_cb>, generates and returns a callback that, |
664 | when invoked, will save it's arguments and notify the coroutine that |
686 | when invoked, will save its arguments and notify the coroutine that |
665 | created the callback. |
687 | created the callback. |
666 | |
688 | |
667 | The second function, C<rouse_wait>, waits for the callback to be called |
689 | The second function, C<rouse_wait>, waits for the callback to be called |
668 | (by calling C<schedule> to go to sleep) and returns the arguments |
690 | (by calling C<schedule> to go to sleep) and returns the arguments |
669 | originally passed to the callback. |
691 | originally passed to the callback. |
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716 | fix your libc and use a saner backend. |
738 | fix your libc and use a saner backend. |
717 | |
739 | |
718 | =item perl process emulation ("threads") |
740 | =item perl process emulation ("threads") |
719 | |
741 | |
720 | This module is not perl-pseudo-thread-safe. You should only ever use this |
742 | This module is not perl-pseudo-thread-safe. You should only ever use this |
721 | module from the same thread (this requirement might be removed in the |
743 | module from the first thread (this requirement might be removed in the |
722 | future to allow per-thread schedulers, but Coro::State does not yet allow |
744 | future to allow per-thread schedulers, but Coro::State does not yet allow |
723 | this). I recommend disabling thread support and using processes, as having |
745 | this). I recommend disabling thread support and using processes, as having |
724 | the windows process emulation enabled under unix roughly halves perl |
746 | the windows process emulation enabled under unix roughly halves perl |
725 | performance, even when not used. |
747 | performance, even when not used. |
726 | |
748 | |
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743 | |
765 | |
744 | Debugging: L<Coro::Debug>. |
766 | Debugging: L<Coro::Debug>. |
745 | |
767 | |
746 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
768 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
747 | |
769 | |
748 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
770 | Locking and IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
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771 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
749 | |
772 | |
750 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
773 | I/O and Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
751 | |
774 | |
752 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
775 | Compatibility with other modules: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
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776 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
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777 | L<Coro::Select>. |
753 | |
778 | |
754 | XS API: L<Coro::MakeMaker>. |
779 | XS API: L<Coro::MakeMaker>. |
755 | |
780 | |
756 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
781 | Low level Configuration, Thread Environment, Continuations: L<Coro::State>. |
757 | |
782 | |
758 | =head1 AUTHOR |
783 | =head1 AUTHOR |
759 | |
784 | |
760 | Marc Lehmann <schmorp@schmorp.de> |
785 | Marc Lehmann <schmorp@schmorp.de> |
761 | http://home.schmorp.de/ |
786 | http://home.schmorp.de/ |