… | |
… | |
67 | |
67 | |
68 | =cut |
68 | =cut |
69 | |
69 | |
70 | package Coro; |
70 | package Coro; |
71 | |
71 | |
72 | use strict qw(vars subs); |
72 | use common::sense; |
73 | no warnings "uninitialized"; |
73 | |
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74 | use Carp (); |
74 | |
75 | |
75 | use Guard (); |
76 | use Guard (); |
76 | |
77 | |
77 | use Coro::State; |
78 | use Coro::State; |
78 | |
79 | |
… | |
… | |
80 | |
81 | |
81 | our $idle; # idle handler |
82 | our $idle; # idle handler |
82 | our $main; # main coro |
83 | our $main; # main coro |
83 | our $current; # current coro |
84 | our $current; # current coro |
84 | |
85 | |
85 | our $VERSION = 5.17; |
86 | our $VERSION = 5.25; |
86 | |
87 | |
87 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
88 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
88 | our %EXPORT_TAGS = ( |
89 | our %EXPORT_TAGS = ( |
89 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
90 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
90 | ); |
91 | ); |
91 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
92 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
92 | |
93 | |
… | |
… | |
123 | |
124 | |
124 | This variable is mainly useful to integrate Coro into event loops. It is |
125 | This variable is mainly useful to integrate Coro into event loops. It is |
125 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
126 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
126 | pretty low-level functionality. |
127 | pretty low-level functionality. |
127 | |
128 | |
128 | This variable stores either a Coro object or a callback. |
129 | This variable stores a Coro object that is put into the ready queue when |
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130 | there are no other ready threads (without invoking any ready hooks). |
129 | |
131 | |
130 | If it is a callback, the it is called whenever the scheduler finds no |
132 | The default implementation dies with "FATAL: deadlock detected.", followed |
131 | ready coros to run. The default implementation prints "FATAL: |
133 | by a thread listing, because the program has no other way to continue. |
132 | deadlock detected" and exits, because the program has no other way to |
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133 | continue. |
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134 | |
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135 | If it is a coro object, then this object will be readied (without |
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136 | invoking any ready hooks, however) when the scheduler finds no other ready |
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137 | coros to run. |
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138 | |
134 | |
139 | This hook is overwritten by modules such as C<Coro::EV> and |
135 | This hook is overwritten by modules such as C<Coro::EV> and |
140 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
136 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
141 | coro so the scheduler can run it. |
137 | coro so the scheduler can run it. |
142 | |
138 | |
143 | Note that the callback I<must not>, under any circumstances, block |
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144 | the current coro. Normally, this is achieved by having an "idle |
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145 | coro" that calls the event loop and then blocks again, and then |
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146 | readying that coro in the idle handler, or by simply placing the idle |
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147 | coro in this variable. |
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148 | |
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149 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
139 | See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique. |
150 | technique. |
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151 | |
140 | |
152 | Please note that if your callback recursively invokes perl (e.g. for event |
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153 | handlers), then it must be prepared to be called recursively itself. |
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154 | |
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155 | =cut |
141 | =cut |
156 | |
142 | |
157 | $idle = sub { |
143 | # ||= because other modules could have provided their own by now |
158 | require Carp; |
144 | $idle ||= new Coro sub { |
159 | Carp::croak ("FATAL: deadlock detected"); |
145 | require Coro::Debug; |
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146 | die "FATAL: deadlock detected.\n" |
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147 | . Coro::Debug::ps_listing (); |
160 | }; |
148 | }; |
161 | |
149 | |
162 | # this coro is necessary because a coro |
150 | # this coro is necessary because a coro |
163 | # cannot destroy itself. |
151 | # cannot destroy itself. |
164 | our @destroy; |
152 | our @destroy; |
… | |
… | |
272 | =item schedule |
260 | =item schedule |
273 | |
261 | |
274 | Calls the scheduler. The scheduler will find the next coro that is |
262 | Calls the scheduler. The scheduler will find the next coro that is |
275 | to be run from the ready queue and switches to it. The next coro |
263 | to be run from the ready queue and switches to it. The next coro |
276 | to be run is simply the one with the highest priority that is longest |
264 | to be run is simply the one with the highest priority that is longest |
277 | in its ready queue. If there is no coro ready, it will clal the |
265 | in its ready queue. If there is no coro ready, it will call the |
278 | C<$Coro::idle> hook. |
266 | C<$Coro::idle> hook. |
279 | |
267 | |
280 | Please note that the current coro will I<not> be put into the ready |
268 | Please note that the current coro will I<not> be put into the ready |
281 | queue, so calling this function usually means you will never be called |
269 | queue, so calling this function usually means you will never be called |
282 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
270 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
… | |
… | |
625 | Sets (or gets in case the argument is missing) the description for this |
613 | Sets (or gets in case the argument is missing) the description for this |
626 | coro. This is just a free-form string you can associate with a |
614 | coro. This is just a free-form string you can associate with a |
627 | coro. |
615 | coro. |
628 | |
616 | |
629 | This method simply sets the C<< $coro->{desc} >> member to the given |
617 | This method simply sets the C<< $coro->{desc} >> member to the given |
630 | string. You can modify this member directly if you wish. |
618 | string. You can modify this member directly if you wish, and in fact, this |
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619 | is often preferred to indicate major processing states that cna then be |
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620 | seen for example in a L<Coro::Debug> session: |
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621 | |
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622 | sub my_long_function { |
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623 | local $Coro::current->{desc} = "now in my_long_function"; |
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624 | ... |
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625 | $Coro::current->{desc} = "my_long_function: phase 1"; |
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626 | ... |
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627 | $Coro::current->{desc} = "my_long_function: phase 2"; |
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628 | ... |
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629 | } |
631 | |
630 | |
632 | =cut |
631 | =cut |
633 | |
632 | |
634 | sub desc { |
633 | sub desc { |
635 | my $old = $_[0]{desc}; |
634 | my $old = $_[0]{desc}; |
… | |
… | |
672 | returning a new coderef. Unblocking means that calling the new coderef |
671 | returning a new coderef. Unblocking means that calling the new coderef |
673 | will return immediately without blocking, returning nothing, while the |
672 | will return immediately without blocking, returning nothing, while the |
674 | original code ref will be called (with parameters) from within another |
673 | original code ref will be called (with parameters) from within another |
675 | coro. |
674 | coro. |
676 | |
675 | |
677 | The reason this function exists is that many event libraries (such as the |
676 | The reason this function exists is that many event libraries (such as |
678 | venerable L<Event|Event> module) are not thread-safe (a weaker form |
677 | the venerable L<Event|Event> module) are not thread-safe (a weaker form |
679 | of reentrancy). This means you must not block within event callbacks, |
678 | of reentrancy). This means you must not block within event callbacks, |
680 | otherwise you might suffer from crashes or worse. The only event library |
679 | otherwise you might suffer from crashes or worse. The only event library |
681 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
680 | currently known that is safe to use without C<unblock_sub> is L<EV> (but |
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681 | you might still run into deadlocks if all event loops are blocked). |
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682 | |
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683 | Coro will try to catch you when you block in the event loop |
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684 | ("FATAL:$Coro::IDLE blocked itself"), but this is just best effort and |
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685 | only works when you do not run your own event loop. |
682 | |
686 | |
683 | This function allows your callbacks to block by executing them in another |
687 | This function allows your callbacks to block by executing them in another |
684 | coro where it is safe to block. One example where blocking is handy |
688 | coro where it is safe to block. One example where blocking is handy |
685 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
689 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
686 | disk, for example. |
690 | disk, for example. |
… | |
… | |
728 | unshift @unblock_queue, [$cb, @_]; |
732 | unshift @unblock_queue, [$cb, @_]; |
729 | $unblock_scheduler->ready; |
733 | $unblock_scheduler->ready; |
730 | } |
734 | } |
731 | } |
735 | } |
732 | |
736 | |
733 | =item $cb = Coro::rouse_cb |
737 | =item $cb = rouse_cb |
734 | |
738 | |
735 | Create and return a "rouse callback". That's a code reference that, |
739 | Create and return a "rouse callback". That's a code reference that, |
736 | when called, will remember a copy of its arguments and notify the owner |
740 | when called, will remember a copy of its arguments and notify the owner |
737 | coro of the callback. |
741 | coro of the callback. |
738 | |
742 | |
739 | See the next function. |
743 | See the next function. |
740 | |
744 | |
741 | =item @args = Coro::rouse_wait [$cb] |
745 | =item @args = rouse_wait [$cb] |
742 | |
746 | |
743 | Wait for the specified rouse callback (or the last one that was created in |
747 | Wait for the specified rouse callback (or the last one that was created in |
744 | this coro). |
748 | this coro). |
745 | |
749 | |
746 | As soon as the callback is invoked (or when the callback was invoked |
750 | As soon as the callback is invoked (or when the callback was invoked |
… | |
… | |
752 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
756 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
753 | |
757 | |
754 | =back |
758 | =back |
755 | |
759 | |
756 | =cut |
760 | =cut |
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761 | |
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762 | for my $module (qw(Channel RWLock Semaphore SemaphoreSet Signal Specific)) { |
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763 | my $old = defined &{"Coro::$module\::new"} && \&{"Coro::$module\::new"}; |
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764 | |
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765 | *{"Coro::$module\::new"} = sub { |
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766 | require "Coro/$module.pm"; |
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767 | |
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768 | # some modules have their new predefined in State.xs, some don't |
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769 | *{"Coro::$module\::new"} = $old |
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770 | if $old; |
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771 | |
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772 | goto &{"Coro::$module\::new"}; |
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773 | }; |
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774 | } |
757 | |
775 | |
758 | 1; |
776 | 1; |
759 | |
777 | |
760 | =head1 HOW TO WAIT FOR A CALLBACK |
778 | =head1 HOW TO WAIT FOR A CALLBACK |
761 | |
779 | |
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843 | the windows process emulation enabled under unix roughly halves perl |
861 | the windows process emulation enabled under unix roughly halves perl |
844 | performance, even when not used. |
862 | performance, even when not used. |
845 | |
863 | |
846 | =item coro switching is not signal safe |
864 | =item coro switching is not signal safe |
847 | |
865 | |
848 | You must not switch to another coro from within a signal handler |
866 | You must not switch to another coro from within a signal handler (only |
849 | (only relevant with %SIG - most event libraries provide safe signals). |
867 | relevant with %SIG - most event libraries provide safe signals), I<unless> |
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868 | you are sure you are not interrupting a Coro function. |
850 | |
869 | |
851 | That means you I<MUST NOT> call any function that might "block" the |
870 | That means you I<MUST NOT> call any function that might "block" the |
852 | current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
871 | current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
853 | anything that calls those. Everything else, including calling C<ready>, |
872 | anything that calls those. Everything else, including calling C<ready>, |
854 | works. |
873 | works. |
… | |
… | |
864 | ithreads (for example, that memory or files would be shared), showing his |
883 | ithreads (for example, that memory or files would be shared), showing his |
865 | lack of understanding of this area - if it is hard to understand for Chip, |
884 | lack of understanding of this area - if it is hard to understand for Chip, |
866 | it is probably not obvious to everybody). |
885 | it is probably not obvious to everybody). |
867 | |
886 | |
868 | What follows is an ultra-condensed version of my talk about threads in |
887 | What follows is an ultra-condensed version of my talk about threads in |
869 | scripting languages given onthe perl workshop 2009: |
888 | scripting languages given on the perl workshop 2009: |
870 | |
889 | |
871 | The so-called "ithreads" were originally implemented for two reasons: |
890 | The so-called "ithreads" were originally implemented for two reasons: |
872 | first, to (badly) emulate unix processes on native win32 perls, and |
891 | first, to (badly) emulate unix processes on native win32 perls, and |
873 | secondly, to replace the older, real thread model ("5.005-threads"). |
892 | secondly, to replace the older, real thread model ("5.005-threads"). |
874 | |
893 | |