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Comparing Coro/Coro.pm (file contents):
Revision 1.269 by root, Thu Oct 1 23:25:03 2009 UTC vs.
Revision 1.282 by root, Sun Dec 26 16:23:51 2010 UTC

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81 81
82our $idle; # idle handler 82our $idle; # idle handler
83our $main; # main coro 83our $main; # main coro
84our $current; # current coro 84our $current; # current coro
85 85
86our $VERSION = 5.17; 86our $VERSION = 5.25;
87 87
88our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 88our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait);
89our %EXPORT_TAGS = ( 89our %EXPORT_TAGS = (
90 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 90 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
91); 91);
92our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); 92our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
93 93
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124 124
125This variable is mainly useful to integrate Coro into event loops. It is 125This variable is mainly useful to integrate Coro into event loops. It is
126usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is 126usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is
127pretty low-level functionality. 127pretty low-level functionality.
128 128
129This variable stores either a Coro object or a callback. 129This variable stores a Coro object that is put into the ready queue when
130there are no other ready threads (without invoking any ready hooks).
130 131
131If it is a callback, the it is called whenever the scheduler finds no 132The default implementation dies with "FATAL: deadlock detected.", followed
132ready coros to run. The default implementation prints "FATAL: 133by a thread listing, because the program has no other way to continue.
133deadlock detected" and exits, because the program has no other way to
134continue.
135
136If it is a coro object, then this object will be readied (without
137invoking any ready hooks, however) when the scheduler finds no other ready
138coros to run.
139 134
140This hook is overwritten by modules such as C<Coro::EV> and 135This hook is overwritten by modules such as C<Coro::EV> and
141C<Coro::AnyEvent> to wait on an external event that hopefully wake up a 136C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
142coro so the scheduler can run it. 137coro so the scheduler can run it.
143 138
144Note that the callback I<must not>, under any circumstances, block
145the current coro. Normally, this is achieved by having an "idle
146coro" that calls the event loop and then blocks again, and then
147readying that coro in the idle handler, or by simply placing the idle
148coro in this variable.
149
150See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this 139See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique.
151technique.
152 140
153Please note that if your callback recursively invokes perl (e.g. for event
154handlers), then it must be prepared to be called recursively itself.
155
156=cut 141=cut
157 142
158$idle = sub { 143# ||= because other modules could have provided their own by now
159 Carp::confess ("FATAL: deadlock detected"); 144$idle ||= new Coro sub {
145 require Coro::Debug;
146 die "FATAL: deadlock detected.\n"
147 . Coro::Debug::ps_listing ();
160}; 148};
161 149
162# this coro is necessary because a coro 150# this coro is necessary because a coro
163# cannot destroy itself. 151# cannot destroy itself.
164our @destroy; 152our @destroy;
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272=item schedule 260=item schedule
273 261
274Calls the scheduler. The scheduler will find the next coro that is 262Calls the scheduler. The scheduler will find the next coro that is
275to be run from the ready queue and switches to it. The next coro 263to be run from the ready queue and switches to it. The next coro
276to be run is simply the one with the highest priority that is longest 264to be run is simply the one with the highest priority that is longest
277in its ready queue. If there is no coro ready, it will clal the 265in its ready queue. If there is no coro ready, it will call the
278C<$Coro::idle> hook. 266C<$Coro::idle> hook.
279 267
280Please note that the current coro will I<not> be put into the ready 268Please note that the current coro will I<not> be put into the ready
281queue, so calling this function usually means you will never be called 269queue, so calling this function usually means you will never be called
282again unless something else (e.g. an event handler) calls C<< ->ready >>, 270again unless something else (e.g. an event handler) calls C<< ->ready >>,
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625Sets (or gets in case the argument is missing) the description for this 613Sets (or gets in case the argument is missing) the description for this
626coro. This is just a free-form string you can associate with a 614coro. This is just a free-form string you can associate with a
627coro. 615coro.
628 616
629This method simply sets the C<< $coro->{desc} >> member to the given 617This method simply sets the C<< $coro->{desc} >> member to the given
630string. You can modify this member directly if you wish. 618string. You can modify this member directly if you wish, and in fact, this
619is often preferred to indicate major processing states that cna then be
620seen for example in a L<Coro::Debug> session:
621
622 sub my_long_function {
623 local $Coro::current->{desc} = "now in my_long_function";
624 ...
625 $Coro::current->{desc} = "my_long_function: phase 1";
626 ...
627 $Coro::current->{desc} = "my_long_function: phase 2";
628 ...
629 }
631 630
632=cut 631=cut
633 632
634sub desc { 633sub desc {
635 my $old = $_[0]{desc}; 634 my $old = $_[0]{desc};
… …
672returning a new coderef. Unblocking means that calling the new coderef 671returning a new coderef. Unblocking means that calling the new coderef
673will return immediately without blocking, returning nothing, while the 672will return immediately without blocking, returning nothing, while the
674original code ref will be called (with parameters) from within another 673original code ref will be called (with parameters) from within another
675coro. 674coro.
676 675
677The reason this function exists is that many event libraries (such as the 676The reason this function exists is that many event libraries (such as
678venerable L<Event|Event> module) are not thread-safe (a weaker form 677the venerable L<Event|Event> module) are not thread-safe (a weaker form
679of reentrancy). This means you must not block within event callbacks, 678of reentrancy). This means you must not block within event callbacks,
680otherwise you might suffer from crashes or worse. The only event library 679otherwise you might suffer from crashes or worse. The only event library
681currently known that is safe to use without C<unblock_sub> is L<EV>. 680currently known that is safe to use without C<unblock_sub> is L<EV> (but
681you might still run into deadlocks if all event loops are blocked).
682
683Coro will try to catch you when you block in the event loop
684("FATAL:$Coro::IDLE blocked itself"), but this is just best effort and
685only works when you do not run your own event loop.
682 686
683This function allows your callbacks to block by executing them in another 687This function allows your callbacks to block by executing them in another
684coro where it is safe to block. One example where blocking is handy 688coro where it is safe to block. One example where blocking is handy
685is when you use the L<Coro::AIO|Coro::AIO> functions to save results to 689is when you use the L<Coro::AIO|Coro::AIO> functions to save results to
686disk, for example. 690disk, 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 $cb = rouse_cb
734 738
735Create and return a "rouse callback". That's a code reference that, 739Create and return a "rouse callback". That's a code reference that,
736when called, will remember a copy of its arguments and notify the owner 740when called, will remember a copy of its arguments and notify the owner
737coro of the callback. 741coro of the callback.
738 742
739See the next function. 743See the next function.
740 744
741=item @args = Coro::rouse_wait [$cb] 745=item @args = rouse_wait [$cb]
742 746
743Wait for the specified rouse callback (or the last one that was created in 747Wait for the specified rouse callback (or the last one that was created in
744this coro). 748this coro).
745 749
746As soon as the callback is invoked (or when the callback was invoked 750As soon as the callback is invoked (or when the callback was invoked
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843the windows process emulation enabled under unix roughly halves perl 847the windows process emulation enabled under unix roughly halves perl
844performance, even when not used. 848performance, even when not used.
845 849
846=item coro switching is not signal safe 850=item coro switching is not signal safe
847 851
848You must not switch to another coro from within a signal handler 852You must not switch to another coro from within a signal handler (only
849(only relevant with %SIG - most event libraries provide safe signals). 853relevant with %SIG - most event libraries provide safe signals), I<unless>
854you are sure you are not interrupting a Coro function.
850 855
851That means you I<MUST NOT> call any function that might "block" the 856That means you I<MUST NOT> call any function that might "block" the
852current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or 857current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
853anything that calls those. Everything else, including calling C<ready>, 858anything that calls those. Everything else, including calling C<ready>,
854works. 859works.
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864ithreads (for example, that memory or files would be shared), showing his 869ithreads (for example, that memory or files would be shared), showing his
865lack of understanding of this area - if it is hard to understand for Chip, 870lack of understanding of this area - if it is hard to understand for Chip,
866it is probably not obvious to everybody). 871it is probably not obvious to everybody).
867 872
868What follows is an ultra-condensed version of my talk about threads in 873What follows is an ultra-condensed version of my talk about threads in
869scripting languages given onthe perl workshop 2009: 874scripting languages given on the perl workshop 2009:
870 875
871The so-called "ithreads" were originally implemented for two reasons: 876The so-called "ithreads" were originally implemented for two reasons:
872first, to (badly) emulate unix processes on native win32 perls, and 877first, to (badly) emulate unix processes on native win32 perls, and
873secondly, to replace the older, real thread model ("5.005-threads"). 878secondly, to replace the older, real thread model ("5.005-threads").
874 879

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