… | |
… | |
16 | cede; # yield to coro |
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; |
|
|
22 | my $lock = new Coro::Semaphore; |
21 | my $lock = new Coro::Semaphore; |
23 | my $locked; |
22 | my $locked; |
24 | |
23 | |
25 | $lock->down; |
24 | $lock->down; |
26 | $locked = 1; |
25 | $locked = 1; |
… | |
… | |
90 | } 1, 2, 3; |
89 | } 1, 2, 3; |
91 | |
90 | |
92 | This creates a new coro thread and puts it into the ready queue, meaning |
91 | This creates a new coro thread and puts it into the ready queue, meaning |
93 | it will run as soon as the CPU is free for it. |
92 | it will run as soon as the CPU is free for it. |
94 | |
93 | |
95 | C<async> will return a coro object - you can store this for future |
94 | C<async> will return a Coro object - you can store this for future |
96 | reference or ignore it, the thread itself will keep a reference to it's |
95 | reference or ignore it - a thread that is running, ready to run or waiting |
97 | thread object - threads are alive on their own. |
96 | for some event is alive on it's own. |
98 | |
97 | |
99 | Another way to create a thread is to call the C<new> constructor with a |
98 | Another way to create a thread is to call the C<new> constructor with a |
100 | code-reference: |
99 | code-reference: |
101 | |
100 | |
102 | new Coro sub { |
101 | new Coro sub { |
… | |
… | |
131 | A lot can happen after the coro thread has started running. Quite usually, |
130 | A lot can happen after the coro thread has started running. Quite usually, |
132 | it will not run to the end in one go (because you could use a function |
131 | it will not run to the end in one go (because you could use a function |
133 | instead), but it will give up the CPU regularly because it waits for |
132 | instead), but it will give up the CPU regularly because it waits for |
134 | external events. |
133 | external events. |
135 | |
134 | |
136 | As long as a coro thread runs, it's coro object is available in the global |
135 | As long as a coro thread runs, its Coro object is available in the global |
137 | variable C<$Coro::current>. |
136 | variable C<$Coro::current>. |
138 | |
137 | |
139 | The low-level way to give up the CPU is to call the scheduler, which |
138 | The low-level way to give up the CPU is to call the scheduler, which |
140 | selects a new coro thread to run: |
139 | selects a new coro thread to run: |
141 | |
140 | |
… | |
… | |
196 | |
195 | |
197 | async { |
196 | async { |
198 | Coro::terminate "return value 1", "return value 2"; |
197 | Coro::terminate "return value 1", "return value 2"; |
199 | }; |
198 | }; |
200 | |
199 | |
201 | And yet another way is to C<< ->cancel >> (or C<< ->safe_cancel >>) the |
200 | Yet another way is to C<< ->cancel >> (or C<< ->safe_cancel >>) the coro |
202 | coro thread from another thread: |
201 | thread from another thread: |
203 | |
202 | |
204 | my $coro = async { |
203 | my $coro = async { |
205 | exit 1; |
204 | exit 1; |
206 | }; |
205 | }; |
207 | |
206 | |
… | |
… | |
219 | So, cancelling a thread that runs in an XS event loop might not be the |
218 | So, cancelling a thread that runs in an XS event loop might not be the |
220 | best idea, but any other combination that deals with perl only (cancelling |
219 | best idea, but any other combination that deals with perl only (cancelling |
221 | when a thread is in a C<tie> method or an C<AUTOLOAD> for example) is |
220 | when a thread is in a C<tie> method or an C<AUTOLOAD> for example) is |
222 | safe. |
221 | safe. |
223 | |
222 | |
|
|
223 | Last not least, a coro thread object that isn't referenced is C<< |
|
|
224 | ->cancel >>'ed automatically - just like other objects in Perl. This |
|
|
225 | is not such a common case, however - a running thread is referencedy by |
|
|
226 | C<$Coro::current>, a thread ready to run is referenced by the ready queue, |
|
|
227 | a thread waiting on a lock or semaphore is referenced by being in some |
|
|
228 | wait list and so on. But a thread that isn't in any of those queues gets |
|
|
229 | cancelled: |
|
|
230 | |
|
|
231 | async { |
|
|
232 | schedule; # cede to other coros, don't go into the ready queue |
|
|
233 | }; |
|
|
234 | |
|
|
235 | cede; |
|
|
236 | # now the async above is destroyed, as it is not referenced by anything. |
|
|
237 | |
|
|
238 | A slightly embellished example might make it clearer: |
|
|
239 | |
|
|
240 | async { |
|
|
241 | my $guard = Guard::guard { print "destroyed\n" }; |
|
|
242 | schedule while 1; |
|
|
243 | }; |
|
|
244 | |
|
|
245 | cede; |
|
|
246 | |
|
|
247 | Superficially one might not expect any output - since the C<async> |
|
|
248 | implements an endless loop, the C<$guard> will not be cleaned up. However, |
|
|
249 | since the thread object returned by C<async> is not stored anywhere, the |
|
|
250 | thread is initially referenced because it is in the ready queue, when it |
|
|
251 | runs it is referenced by C<$Coro::current>, but when it calls C<schedule>, |
|
|
252 | it gets C<cancel>ed causing the guard object to be destroyed (see the next |
|
|
253 | section), and printing it's message. |
|
|
254 | |
|
|
255 | If this seems a bit drastic, remember that this only happens when nothing |
|
|
256 | references the thread anymore, which means there is no way to further |
|
|
257 | execute it, ever. The only options at this point are leaking the thread, |
|
|
258 | or cleaning it up, which brings us to... |
|
|
259 | |
224 | =item 5. Cleanup |
260 | =item 5. Cleanup |
225 | |
261 | |
226 | Threads will allocate various resources. Most but not all will be returned |
262 | Threads will allocate various resources. Most but not all will be returned |
227 | when a thread terminates, during clean-up. |
263 | when a thread terminates, during clean-up. |
228 | |
264 | |
… | |
… | |
246 | |
282 | |
247 | my $sem = new Coro::Semaphore; |
283 | my $sem = new Coro::Semaphore; |
248 | |
284 | |
249 | async { |
285 | async { |
250 | my $lock_guard = $sem->guard; |
286 | my $lock_guard = $sem->guard; |
251 | # if we reutrn, or die or get cancelled, here, |
287 | # if we return, or die or get cancelled, here, |
252 | # then the semaphore will be "up"ed. |
288 | # then the semaphore will be "up"ed. |
253 | }; |
289 | }; |
254 | |
290 | |
255 | The C<Guard::guard> function comes in handy for any custom cleanup you |
291 | The C<Guard::guard> function comes in handy for any custom cleanup you |
256 | might want to do: |
292 | might want to do (but you cannot switch to other coroutines from those |
|
|
293 | code blocks): |
257 | |
294 | |
258 | async { |
295 | async { |
259 | my $window = new Gtk2::Window "toplevel"; |
296 | my $window = new Gtk2::Window "toplevel"; |
260 | # The window will not be cleaned up automatically, even when $window |
297 | # The window will not be cleaned up automatically, even when $window |
261 | # gets freed, so use a guard to ensure it's destruction |
298 | # gets freed, so use a guard to ensure it's destruction |
… | |
… | |
274 | # if we return or die here, the description will be restored |
311 | # if we return or die here, the description will be restored |
275 | } |
312 | } |
276 | |
313 | |
277 | =item 6. Viva La Zombie Muerte |
314 | =item 6. Viva La Zombie Muerte |
278 | |
315 | |
279 | Even after a thread has terminated and cleaned up it's resources, the coro |
316 | Even after a thread has terminated and cleaned up its resources, the Coro |
280 | object still is there and stores the return values of the thread. Only in |
317 | object still is there and stores the return values of the thread. |
281 | this state will the coro object be "reference counted" in the normal perl |
|
|
282 | sense: the thread code keeps a reference to it when it is active, but not |
|
|
283 | after it has terminated. |
|
|
284 | |
318 | |
285 | The means the coro object gets freed automatically when the thread has |
319 | When there are no other references, it will simply be cleaned up and |
286 | terminated and cleaned up and there arenot other references. |
320 | freed. |
287 | |
321 | |
288 | If there are, the coro object will stay around, and you can call C<< |
322 | If there areany references, the Coro object will stay around, and you |
289 | ->join >> as many times as you wish to retrieve the result values: |
323 | can call C<< ->join >> as many times as you wish to retrieve the result |
|
|
324 | values: |
290 | |
325 | |
291 | async { |
326 | async { |
292 | print "hi\n"; |
327 | print "hi\n"; |
293 | 1 |
328 | 1 |
294 | }; |
329 | }; |
… | |
… | |
331 | |
366 | |
332 | our $idle; # idle handler |
367 | our $idle; # idle handler |
333 | our $main; # main coro |
368 | our $main; # main coro |
334 | our $current; # current coro |
369 | our $current; # current coro |
335 | |
370 | |
336 | our $VERSION = 5.372; |
371 | our $VERSION = 6.33; |
337 | |
372 | |
338 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
373 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
339 | our %EXPORT_TAGS = ( |
374 | our %EXPORT_TAGS = ( |
340 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
375 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
341 | ); |
376 | ); |
… | |
… | |
346 | =over 4 |
381 | =over 4 |
347 | |
382 | |
348 | =item $Coro::main |
383 | =item $Coro::main |
349 | |
384 | |
350 | This variable stores the Coro object that represents the main |
385 | This variable stores the Coro object that represents the main |
351 | program. While you cna C<ready> it and do most other things you can do to |
386 | program. While you can C<ready> it and do most other things you can do to |
352 | coro, it is mainly useful to compare again C<$Coro::current>, to see |
387 | coro, it is mainly useful to compare again C<$Coro::current>, to see |
353 | whether you are running in the main program or not. |
388 | whether you are running in the main program or not. |
354 | |
389 | |
355 | =cut |
390 | =cut |
356 | |
391 | |
… | |
… | |
617 | Coro::on_enter { |
652 | Coro::on_enter { |
618 | # on entering the thread, we set an VTALRM handler to cede |
653 | # on entering the thread, we set an VTALRM handler to cede |
619 | $SIG{VTALRM} = sub { cede }; |
654 | $SIG{VTALRM} = sub { cede }; |
620 | # and then start the interval timer |
655 | # and then start the interval timer |
621 | Time::HiRes::setitimer &Time::HiRes::ITIMER_VIRTUAL, 0.01, 0.01; |
656 | Time::HiRes::setitimer &Time::HiRes::ITIMER_VIRTUAL, 0.01, 0.01; |
622 | }; |
657 | }; |
623 | Coro::on_leave { |
658 | Coro::on_leave { |
624 | # on leaving the thread, we stop the interval timer again |
659 | # on leaving the thread, we stop the interval timer again |
625 | Time::HiRes::setitimer &Time::HiRes::ITIMER_VIRTUAL, 0, 0; |
660 | Time::HiRes::setitimer &Time::HiRes::ITIMER_VIRTUAL, 0, 0; |
626 | }; |
661 | }; |
627 | |
662 | |
628 | &{+shift}; |
663 | &{+shift}; |
629 | } |
664 | } |
630 | |
665 | |
631 | # use like this: |
666 | # use like this: |
632 | timeslice { |
667 | timeslice { |
633 | # The following is an endless loop that would normally |
668 | # The following is an endless loop that would normally |
634 | # monopolise the process. Since it runs in a timesliced |
669 | # monopolise the process. Since it runs in a timesliced |
635 | # environment, it will regularly cede to other threads. |
670 | # environment, it will regularly cede to other threads. |
636 | while () { } |
671 | while () { } |
637 | }; |
672 | }; |
638 | |
673 | |
639 | |
674 | |
640 | =item killall |
675 | =item killall |
641 | |
676 | |
642 | Kills/terminates/cancels all coros except the currently running one. |
677 | Kills/terminates/cancels all coros except the currently running one. |
… | |
… | |
713 | To avoid this, it is best to put a suspended coro into the ready queue |
748 | To avoid this, it is best to put a suspended coro into the ready queue |
714 | unconditionally, as every synchronisation mechanism must protect itself |
749 | unconditionally, as every synchronisation mechanism must protect itself |
715 | against spurious wakeups, and the one in the Coro family certainly do |
750 | against spurious wakeups, and the one in the Coro family certainly do |
716 | that. |
751 | that. |
717 | |
752 | |
|
|
753 | =item $state->is_new |
|
|
754 | |
|
|
755 | Returns true iff this Coro object is "new", i.e. has never been run |
|
|
756 | yet. Those states basically consist of only the code reference to call and |
|
|
757 | the arguments, but consumes very little other resources. New states will |
|
|
758 | automatically get assigned a perl interpreter when they are transfered to. |
|
|
759 | |
|
|
760 | =item $state->is_zombie |
|
|
761 | |
|
|
762 | Returns true iff the Coro object has been cancelled, i.e. |
|
|
763 | it's resources freed because they were C<cancel>'ed, C<terminate>'d, |
|
|
764 | C<safe_cancel>'ed or simply went out of scope. |
|
|
765 | |
|
|
766 | The name "zombie" stems from UNIX culture, where a process that has |
|
|
767 | exited and only stores and exit status and no other resources is called a |
|
|
768 | "zombie". |
|
|
769 | |
718 | =item $is_ready = $coro->is_ready |
770 | =item $is_ready = $coro->is_ready |
719 | |
771 | |
720 | Returns true iff the Coro object is in the ready queue. Unless the Coro |
772 | Returns true iff the Coro object is in the ready queue. Unless the Coro |
721 | object gets destroyed, it will eventually be scheduled by the scheduler. |
773 | object gets destroyed, it will eventually be scheduled by the scheduler. |
722 | |
774 | |
… | |
… | |
738 | current Coro. |
790 | current Coro. |
739 | |
791 | |
740 | This is a rather brutal way to free a coro, with some limitations - if |
792 | This is a rather brutal way to free a coro, with some limitations - if |
741 | the thread is inside a C callback that doesn't expect to be canceled, |
793 | the thread is inside a C callback that doesn't expect to be canceled, |
742 | bad things can happen, or if the cancelled thread insists on running |
794 | bad things can happen, or if the cancelled thread insists on running |
743 | complicated cleanup handlers that rely on it'S thread context, things will |
795 | complicated cleanup handlers that rely on its thread context, things will |
744 | not work. |
796 | not work. |
745 | |
797 | |
746 | Any cleanup code being run (e.g. from C<guard> blocks) will be run without |
798 | Any cleanup code being run (e.g. from C<guard> blocks) will be run without |
747 | a thread context, and is not allowed to switch to other threads. On the |
799 | a thread context, and is not allowed to switch to other threads. On the |
748 | plus side, C<< ->cancel >> will always clean up the thread, no matter |
800 | plus side, C<< ->cancel >> will always clean up the thread, no matter |
… | |
… | |
854 | Wait until the coro terminates and return any values given to the |
906 | Wait until the coro terminates and return any values given to the |
855 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
907 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
856 | from multiple threads, and all will be resumed and given the status |
908 | from multiple threads, and all will be resumed and given the status |
857 | return once the C<$coro> terminates. |
909 | return once the C<$coro> terminates. |
858 | |
910 | |
859 | =cut |
|
|
860 | |
|
|
861 | sub xjoin { |
|
|
862 | my $self = shift; |
|
|
863 | |
|
|
864 | unless ($self->{_status}) { |
|
|
865 | my $current = $current; |
|
|
866 | |
|
|
867 | push @{$self->{_on_destroy}}, sub { |
|
|
868 | $current->ready; |
|
|
869 | undef $current; |
|
|
870 | }; |
|
|
871 | |
|
|
872 | &schedule while $current; |
|
|
873 | } |
|
|
874 | |
|
|
875 | wantarray ? @{$self->{_status}} : $self->{_status}[0] |
|
|
876 | } |
|
|
877 | |
|
|
878 | =item $coro->on_destroy (\&cb) |
911 | =item $coro->on_destroy (\&cb) |
879 | |
912 | |
880 | Registers a callback that is called when this coro thread gets destroyed, |
913 | Registers a callback that is called when this coro thread gets destroyed, |
881 | that is, after it's resources have been freed but before it is joined. The |
914 | that is, after it's resources have been freed but before it is joined. The |
882 | callback gets passed the terminate/cancel arguments, if any, and I<must |
915 | callback gets passed the terminate/cancel arguments, if any, and I<must |
883 | not> die, under any circumstances. |
916 | not> die, under any circumstances. |
884 | |
917 | |
885 | There can be any number of C<on_destroy> callbacks per coro, and there is |
918 | There can be any number of C<on_destroy> callbacks per coro, and there is |
886 | no way currently to remove a callback once added. |
919 | currently no way to remove a callback once added. |
887 | |
|
|
888 | =cut |
|
|
889 | |
|
|
890 | sub xon_destroy { |
|
|
891 | my ($self, $cb) = @_; |
|
|
892 | |
|
|
893 | push @{ $self->{_on_destroy} }, $cb; |
|
|
894 | } |
|
|
895 | |
920 | |
896 | =item $oldprio = $coro->prio ($newprio) |
921 | =item $oldprio = $coro->prio ($newprio) |
897 | |
922 | |
898 | Sets (or gets, if the argument is missing) the priority of the |
923 | Sets (or gets, if the argument is missing) the priority of the |
899 | coro thread. Higher priority coro get run before lower priority |
924 | coro thread. Higher priority coro get run before lower priority |
… | |
… | |
926 | coro thread. This is just a free-form string you can associate with a |
951 | coro thread. This is just a free-form string you can associate with a |
927 | coro. |
952 | coro. |
928 | |
953 | |
929 | This method simply sets the C<< $coro->{desc} >> member to the given |
954 | This method simply sets the C<< $coro->{desc} >> member to the given |
930 | string. You can modify this member directly if you wish, and in fact, this |
955 | string. You can modify this member directly if you wish, and in fact, this |
931 | is often preferred to indicate major processing states that cna then be |
956 | is often preferred to indicate major processing states that can then be |
932 | seen for example in a L<Coro::Debug> session: |
957 | seen for example in a L<Coro::Debug> session: |
933 | |
958 | |
934 | sub my_long_function { |
959 | sub my_long_function { |
935 | local $Coro::current->{desc} = "now in my_long_function"; |
960 | local $Coro::current->{desc} = "now in my_long_function"; |
936 | ... |
961 | ... |
… | |
… | |
1105 | But from within a coro, you often just want to write this: |
1130 | But from within a coro, you often just want to write this: |
1106 | |
1131 | |
1107 | my $status = wait_for_child $pid; |
1132 | my $status = wait_for_child $pid; |
1108 | |
1133 | |
1109 | Coro offers two functions specifically designed to make this easy, |
1134 | Coro offers two functions specifically designed to make this easy, |
1110 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
1135 | C<rouse_cb> and C<rouse_wait>. |
1111 | |
1136 | |
1112 | The first function, C<rouse_cb>, generates and returns a callback that, |
1137 | The first function, C<rouse_cb>, generates and returns a callback that, |
1113 | when invoked, will save its arguments and notify the coro that |
1138 | when invoked, will save its arguments and notify the coro that |
1114 | created the callback. |
1139 | created the callback. |
1115 | |
1140 | |
… | |
… | |
1121 | function mentioned above: |
1146 | function mentioned above: |
1122 | |
1147 | |
1123 | sub wait_for_child($) { |
1148 | sub wait_for_child($) { |
1124 | my ($pid) = @_; |
1149 | my ($pid) = @_; |
1125 | |
1150 | |
1126 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
1151 | my $watcher = AnyEvent->child (pid => $pid, cb => rouse_cb); |
1127 | |
1152 | |
1128 | my ($rpid, $rstatus) = Coro::rouse_wait; |
1153 | my ($rpid, $rstatus) = rouse_wait; |
1129 | $rstatus |
1154 | $rstatus |
1130 | } |
1155 | } |
1131 | |
1156 | |
1132 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
1157 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
1133 | you can roll your own, using C<schedule>: |
1158 | you can roll your own, using C<schedule> and C<ready>: |
1134 | |
1159 | |
1135 | sub wait_for_child($) { |
1160 | sub wait_for_child($) { |
1136 | my ($pid) = @_; |
1161 | my ($pid) = @_; |
1137 | |
1162 | |
1138 | # store the current coro in $current, |
1163 | # store the current coro in $current, |
… | |
… | |
1141 | my ($done, $rstatus); |
1166 | my ($done, $rstatus); |
1142 | |
1167 | |
1143 | # pass a closure to ->child |
1168 | # pass a closure to ->child |
1144 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
1169 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
1145 | $rstatus = $_[1]; # remember rstatus |
1170 | $rstatus = $_[1]; # remember rstatus |
1146 | $done = 1; # mark $rstatus as valud |
1171 | $done = 1; # mark $rstatus as valid |
|
|
1172 | $current->ready; # wake up the waiting thread |
1147 | }); |
1173 | }); |
1148 | |
1174 | |
1149 | # wait until the closure has been called |
1175 | # wait until the closure has been called |
1150 | schedule while !$done; |
1176 | schedule while !$done; |
1151 | |
1177 | |