[ViewVC] Diff of: cvs/Coro/Coro.pm

Comparing Coro/Coro.pm (file contents):
Revision 1.114 by root, Wed Jan 24 16:22:08 2007 UTC vs.
Revision 1.217 by root, Fri Nov 14 23:48:10 2008 UTC

…		…
2		2
3	Coro - coroutine process abstraction	3	Coro - coroutine process abstraction
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use Coro;	7	use Coro;
8		8
9	async {	9	async {
10	# some asynchronous thread of execution	10	# some asynchronous thread of execution
		11	print "2\n";
		12	cede; # yield back to main
		13	print "4\n";
11	};	14	};
12		15	print "1\n";
13	# alternatively create an async coroutine like this:	16	cede; # yield to coroutine
14		17	print "3\n";
15	sub some_func : Coro {	18	cede; # and again
16	# some more async code	19
17	}	20	# use locking
18		21	use Coro::Semaphore;
19	cede;	22	my $lock = new Coro::Semaphore;
		23	my $locked;
		24
		25	$lock->down;
		26	$locked = 1;
		27	$lock->up;
20		28
21	=head1 DESCRIPTION	29	=head1 DESCRIPTION
22		30
23	This module collection manages coroutines. Coroutines are similar	31	This module collection manages coroutines. Coroutines are similar to
24	to threads but don't run in parallel at the same time even on SMP	32	threads but don't (in general) run in parallel at the same time even
25	machines. The specific flavor of coroutine use din this module also	33	on SMP machines. The specific flavor of coroutine used in this module
26	guarentees you that it will not switch between coroutines unless	34	also guarantees you that it will not switch between coroutines unless
27	necessary, at easily-identified points in your program, so locking and	35	necessary, at easily-identified points in your program, so locking and
28	parallel access are rarely an issue, making coroutine programming much	36	parallel access are rarely an issue, making coroutine programming much
29	safer than threads programming.	37	safer and easier than threads programming.
30		38
31	(Perl, however, does not natively support real threads but instead does a	39	Unlike a normal perl program, however, coroutines allow you to have
32	very slow and memory-intensive emulation of processes using threads. This	40	multiple running interpreters that share data, which is especially useful
33	is a performance win on Windows machines, and a loss everywhere else).	41	to code pseudo-parallel processes and for event-based programming, such as
		42	multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to
		43	learn more.
		44
		45	Coroutines are also useful because Perl has no support for threads (the so
		46	called "threads" that perl offers are nothing more than the (bad) process
		47	emulation coming from the Windows platform: On standard operating systems
		48	they serve no purpose whatsoever, except by making your programs slow and
		49	making them use a lot of memory. Best disable them when building perl, or
		50	aks your software vendor/distributor to do it for you).
34		51
35	In this module, coroutines are defined as "callchain + lexical variables +	52	In this module, coroutines are defined as "callchain + lexical variables +
36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,	53	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
37	its own set of lexicals and its own set of perls most important global	54	its own set of lexicals and its own set of perls most important global
38	variables.	55	variables (see L<Coro::State> for more configuration).
39		56
40	=cut	57	=cut
41		58
42	package Coro;	59	package Coro;
43		60
44	use strict;	61	use strict qw(vars subs);
45	no warnings "uninitialized";	62	no warnings "uninitialized";
46		63
47	use Coro::State;	64	use Coro::State;
48		65
49	use base qw(Coro::State Exporter);	66	use base qw(Coro::State Exporter);
50		67
51	our $idle; # idle handler	68	our $idle; # idle handler
52	our $main; # main coroutine	69	our $main; # main coroutine
53	our $current; # current coroutine	70	our $current; # current coroutine
54		71
55	our $VERSION = '3.5';	72	our $VERSION = 5.0;
56		73
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	74	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	75	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	76	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	77	);
61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	78	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62		79
63	{
64	my @async;
65	my $init;
66
67	# this way of handling attributes simply is NOT scalable ;()
68	sub import {
69	no strict 'refs';
70
71	Coro->export_to_level (1, @_);
72
73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
75	my ($package, $ref) = (shift, shift);
76	my @attrs;
77	for (@_) {
78	if ($_ eq "Coro") {
79	push @async, $ref;
80	unless ($init++) {
81	eval q{
82	sub INIT {
83	&async(pop @async) while @async;
84	}
85	};
86	}
87	} else {
88	push @attrs, $_;
89	}
90	}
91	return $old ? $old->($package, $ref, @attrs) : @attrs;
92	};
93	}
94
95	}
96
97	=over 4	80	=over 4
98		81
99	=item $main	82	=item $Coro::main
100		83
101	This coroutine represents the main program.	84	This variable stores the coroutine object that represents the main
		85	program. While you cna C<ready> it and do most other things you can do to
		86	coroutines, it is mainly useful to compare again C<$Coro::current>, to see
		87	whether you are running in the main program or not.
102		88
103	=cut	89	=cut
104		90
105	$main = new Coro;	91	$main = new Coro;
106		92
107	=item $current (or as function: current)	93	=item $Coro::current
108		94
109	The current coroutine (the last coroutine switched to). The initial value	95	The coroutine object representing the current coroutine (the last
		96	coroutine that the Coro scheduler switched to). The initial value is
110	is C<$main> (of course).	97	C<$main> (of course).
111		98
112	This variable is B<strictly> I<read-only>. It is provided for performance	99	This variable is B<strictly> I<read-only>. You can take copies of the
113	reasons. If performance is not essentiel you are encouraged to use the	100	value stored in it and use it as any other coroutine object, but you must
114	C<Coro::current> function instead.	101	not otherwise modify the variable itself.
115		102
116	=cut	103	=cut
		104
		105	$main->{desc} = "[main::]";
117		106
118	# maybe some other module used Coro::Specific before...	107	# maybe some other module used Coro::Specific before...
119	$main->{specific} = $current->{specific}	108	$main->{_specific} = $current->{_specific}
120	if $current;	109	if $current;
121		110
122	_set_current $main;	111	_set_current $main;
123		112
124	sub current() { $current }	113	sub current() { $current } # [DEPRECATED]
125		114
126	=item $idle	115	=item $Coro::idle
127		116
128	A callback that is called whenever the scheduler finds no ready coroutines	117	This variable is mainly useful to integrate Coro into event loops. It is
129	to run. The default implementation prints "FATAL: deadlock detected" and	118	usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is
130	exits, because the program has no other way to continue.	119	pretty low-level functionality.
		120
		121	This variable stores a callback that is called whenever the scheduler
		122	finds no ready coroutines to run. The default implementation prints
		123	"FATAL: deadlock detected" and exits, because the program has no other way
		124	to continue.
131		125
132	This hook is overwritten by modules such as C<Coro::Timer> and	126	This hook is overwritten by modules such as C<Coro::Timer> and
133	C<Coro::Event> to wait on an external event that hopefully wake up a	127	C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
134	coroutine so the scheduler can run it.	128	coroutine so the scheduler can run it.
135		129
		130	Note that the callback I<must not>, under any circumstances, block
		131	the current coroutine. Normally, this is achieved by having an "idle
		132	coroutine" that calls the event loop and then blocks again, and then
		133	readying that coroutine in the idle handler.
		134
		135	See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
		136	technique.
		137
136	Please note that if your callback recursively invokes perl (e.g. for event	138	Please note that if your callback recursively invokes perl (e.g. for event
137	handlers), then it must be prepared to be called recursively.	139	handlers), then it must be prepared to be called recursively itself.
138		140
139	=cut	141	=cut
140		142
141	$idle = sub {	143	$idle = sub {
142	require Carp;	144	require Carp;
…		…
149	# free coroutine data and mark as destructed	151	# free coroutine data and mark as destructed
150	$self->_destroy	152	$self->_destroy
151	or return;	153	or return;
152		154
153	# call all destruction callbacks	155	# call all destruction callbacks
154	$_->(@{$self->{status}})	156	$_->(@{$self->{_status}})
155	for @{(delete $self->{destroy_cb}) \|\| []};	157	for @{ delete $self->{_on_destroy} \|\| [] };
156	}	158	}
157		159
158	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
159	# cannot destroy itself.	161	# cannot destroy itself.
160	my @destroy;	162	my @destroy;
…		…
166	while @destroy;	168	while @destroy;
167		169
168	&schedule;	170	&schedule;
169	}	171	}
170	};	172	};
171		173	$manager->{desc} = "[coro manager]";
172	$manager->prio (PRIO_MAX);	174	$manager->prio (PRIO_MAX);
173		175
174	# static methods. not really.
175
176	=back	176	=back
177		177
178	=head2 STATIC METHODS	178	=head2 SIMPLE COROUTINE CREATION
179
180	Static methods are actually functions that operate on the current coroutine only.
181		179
182	=over 4	180	=over 4
183		181
184	=item async { ... } [@args...]	182	=item async { ... } [@args...]
185		183
186	Create a new asynchronous coroutine and return it's coroutine object	184	Create a new coroutine and return it's coroutine object (usually
187	(usually unused). When the sub returns the new coroutine is automatically	185	unused). The coroutine will be put into the ready queue, so
		186	it will start running automatically on the next scheduler run.
		187
		188	The first argument is a codeblock/closure that should be executed in the
		189	coroutine. When it returns argument returns the coroutine is automatically
188	terminated.	190	terminated.
189		191
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	192	The remaining arguments are passed as arguments to the closure.
191		193
192	When the coroutine dies, the program will exit, just as in the main	194	See the C<Coro::State::new> constructor for info about the coroutine
193	program.	195	environment in which coroutines are executed.
194		196
		197	Calling C<exit> in a coroutine will do the same as calling exit outside
		198	the coroutine. Likewise, when the coroutine dies, the program will exit,
		199	just as it would in the main program.
		200
		201	If you do not want that, you can provide a default C<die> handler, or
		202	simply avoid dieing (by use of C<eval>).
		203
195	# create a new coroutine that just prints its arguments	204	Example: Create a new coroutine that just prints its arguments.
		205
196	async {	206	async {
197	print "@_\n";	207	print "@_\n";
198	} 1,2,3,4;	208	} 1,2,3,4;
199		209
200	=cut	210	=cut
…		…
206	}	216	}
207		217
208	=item async_pool { ... } [@args...]	218	=item async_pool { ... } [@args...]
209		219
210	Similar to C<async>, but uses a coroutine pool, so you should not call	220	Similar to C<async>, but uses a coroutine pool, so you should not call
211	terminate or join (although you are allowed to), and you get a coroutine	221	terminate or join on it (although you are allowed to), and you get a
212	that might have executed other code already (which can be good or bad :).	222	coroutine that might have executed other code already (which can be good
		223	or bad :).
213		224
		225	On the plus side, this function is faster than creating (and destroying)
		226	a completly new coroutine, so if you need a lot of generic coroutines in
		227	quick successsion, use C<async_pool>, not C<async>.
		228
214	Also, the block is executed in an C<eval> context and a warning will be	229	The code block is executed in an C<eval> context and a warning will be
215	issued in case of an exception instead of terminating the program, as	230	issued in case of an exception instead of terminating the program, as
216	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>	231	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
217	will not work in the expected way, unless you call terminate or cancel,	232	will not work in the expected way, unless you call terminate or cancel,
218	which somehow defeats the purpose of pooling.	233	which somehow defeats the purpose of pooling (but is fine in the
		234	exceptional case).
219		235
220	The priority will be reset to C<0> after each job, otherwise the coroutine	236	The priority will be reset to C<0> after each run, tracing will be
221	will be re-used "as-is".	237	disabled, the description will be reset and the default output filehandle
		238	gets restored, so you can change all these. Otherwise the coroutine will
		239	be re-used "as-is": most notably if you change other per-coroutine global
		240	stuff such as C<$/> you I<must needs> revert that change, which is most
		241	simply done by using local as in: C<< local $/ >>.
222		242
223	The pool size is limited to 8 idle coroutines (this can be adjusted by	243	The idle pool size is limited to C<8> idle coroutines (this can be
224	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as	244	adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
225	required.	245	coros as required.
226		246
227	If you are concerned about pooled coroutines growing a lot because a	247	If you are concerned about pooled coroutines growing a lot because a
228	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {	248	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
229	terminate }> once per second or so to slowly replenish the pool.	249	{ terminate }> once per second or so to slowly replenish the pool. In
		250	addition to that, when the stacks used by a handler grows larger than 16kb
		251	(adjustable via $Coro::POOL_RSS) it will also be destroyed.
230		252
231	=cut	253	=cut
232		254
233	our $POOL_SIZE = 8;	255	our $POOL_SIZE = 8;
		256	our $POOL_RSS = 16 * 1024;
234	our @pool;	257	our @async_pool;
235		258
236	sub pool_handler {	259	sub pool_handler {
		260	my $cb;
		261
237	while () {	262	while () {
238	eval {	263	eval {
239	my ($cb, @arg) = @{ delete $current->{_invoke} or return };	264	while () {
240	$cb->(@arg);	265	_pool_1 $cb;
		266	&$cb;
		267	_pool_2 $cb;
		268	&schedule;
		269	}
241	};	270	};
		271
		272	if ($@) {
		273	last if $@ eq "\3async_pool terminate\2\n";
242	warn $@ if $@;	274	warn $@;
243		275	}
244	last if @pool >= $POOL_SIZE;
245	push @pool, $current;
246
247	$current->prio (0);
248	schedule;
249	}	276	}
250	}	277	}
251		278
252	sub async_pool(&@) {	279	sub async_pool(&@) {
253	# this is also inlined into the unlock_scheduler	280	# this is also inlined into the unlock_scheduler
254	my $coro = (pop @pool or new Coro \&pool_handler);	281	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
255		282
256	$coro->{_invoke} = [@_];	283	$coro->{_invoke} = [@_];
257	$coro->ready;	284	$coro->ready;
258		285
259	$coro	286	$coro
260	}	287	}
261		288
		289	=back
		290
		291	=head2 STATIC METHODS
		292
		293	Static methods are actually functions that operate on the current coroutine.
		294
		295	=over 4
		296
262	=item schedule	297	=item schedule
263		298
264	Calls the scheduler. Please note that the current coroutine will not be put	299	Calls the scheduler. The scheduler will find the next coroutine that is
		300	to be run from the ready queue and switches to it. The next coroutine
		301	to be run is simply the one with the highest priority that is longest
		302	in its ready queue. If there is no coroutine ready, it will clal the
		303	C<$Coro::idle> hook.
		304
		305	Please note that the current coroutine will I<not> be put into the ready
265	into the ready queue, so calling this function usually means you will	306	queue, so calling this function usually means you will never be called
266	never be called again unless something else (e.g. an event handler) calls	307	again unless something else (e.g. an event handler) calls C<< ->ready >>,
267	ready.	308	thus waking you up.
		309
		310	This makes C<schedule> I<the> generic method to use to block the current
		311	coroutine and wait for events: first you remember the current coroutine in
		312	a variable, then arrange for some callback of yours to call C<< ->ready
		313	>> on that once some event happens, and last you call C<schedule> to put
		314	yourself to sleep. Note that a lot of things can wake your coroutine up,
		315	so you need to check whether the event indeed happened, e.g. by storing the
		316	status in a variable.
268		317
269	The canonical way to wait on external events is this:	318	The canonical way to wait on external events is this:
270		319
271	{	320	{
272	# remember current coroutine	321	# remember current coroutine
…		…
277	# wake up sleeping coroutine	326	# wake up sleeping coroutine
278	$current->ready;	327	$current->ready;
279	undef $current;	328	undef $current;
280	};	329	};
281		330
282	# call schedule until event occured.	331	# call schedule until event occurred.
283	# in case we are woken up for other reasons	332	# in case we are woken up for other reasons
284	# (current still defined), loop.	333	# (current still defined), loop.
285	Coro::schedule while $current;	334	Coro::schedule while $current;
286	}	335	}
287		336
288	=item cede	337	=item cede
289		338
290	"Cede" to other coroutines. This function puts the current coroutine into the	339	"Cede" to other coroutines. This function puts the current coroutine into
291	ready queue and calls C<schedule>, which has the effect of giving up the	340	the ready queue and calls C<schedule>, which has the effect of giving
292	current "timeslice" to other coroutines of the same or higher priority.	341	up the current "timeslice" to other coroutines of the same or higher
		342	priority. Once your coroutine gets its turn again it will automatically be
		343	resumed.
293		344
294	Returns true if at least one coroutine switch has happened.	345	This function is often called C<yield> in other languages.
295		346
296	=item Coro::cede_notself	347	=item Coro::cede_notself
297		348
298	Works like cede, but is not exported by default and will cede to any	349	Works like cede, but is not exported by default and will cede to I<any>
299	coroutine, regardless of priority, once.	350	coroutine, regardless of priority. This is useful sometimes to ensure
300		351	progress is made.
301	Returns true if at least one coroutine switch has happened.
302		352
303	=item terminate [arg...]	353	=item terminate [arg...]
304		354
305	Terminates the current coroutine with the given status values (see L<cancel>).	355	Terminates the current coroutine with the given status values (see L<cancel>).
		356
		357	=item killall
		358
		359	Kills/terminates/cancels all coroutines except the currently running
		360	one. This is useful after a fork, either in the child or the parent, as
		361	usually only one of them should inherit the running coroutines.
		362
		363	Note that while this will try to free some of the main programs resources,
		364	you cannot free all of them, so if a coroutine that is not the main
		365	program calls this function, there will be some one-time resource leak.
306		366
307	=cut	367	=cut
308		368
309	sub terminate {	369	sub terminate {
310	$current->cancel (@_);	370	$current->cancel (@_);
311	}	371	}
312		372
		373	sub killall {
		374	for (Coro::State::list) {
		375	$_->cancel
		376	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		377	}
		378	}
		379
313	=back	380	=back
314		381
315	# dynamic methods
316
317	=head2 COROUTINE METHODS	382	=head2 COROUTINE METHODS
318		383
319	These are the methods you can call on coroutine objects.	384	These are the methods you can call on coroutine objects (or to create
		385	them).
320		386
321	=over 4	387	=over 4
322		388
323	=item new Coro \&sub [, @args...]	389	=item new Coro \&sub [, @args...]
324		390
325	Create a new coroutine and return it. When the sub returns the coroutine	391	Create a new coroutine and return it. When the sub returns, the coroutine
326	automatically terminates as if C<terminate> with the returned values were	392	automatically terminates as if C<terminate> with the returned values were
327	called. To make the coroutine run you must first put it into the ready queue	393	called. To make the coroutine run you must first put it into the ready
328	by calling the ready method.	394	queue by calling the ready method.
329		395
330	Calling C<exit> in a coroutine will not work correctly, so do not do that.	396	See C<async> and C<Coro::State::new> for additional info about the
		397	coroutine environment.
331		398
332	=cut	399	=cut
333		400
334	sub _run_coro {	401	sub _run_coro {
335	terminate &{+shift};	402	terminate &{+shift};
…		…
341	$class->SUPER::new (\&_run_coro, @_)	408	$class->SUPER::new (\&_run_coro, @_)
342	}	409	}
343		410
344	=item $success = $coroutine->ready	411	=item $success = $coroutine->ready
345		412
346	Put the given coroutine into the ready queue (according to it's priority)	413	Put the given coroutine into the end of its ready queue (there is one
347	and return true. If the coroutine is already in the ready queue, do nothing	414	queue for each priority) and return true. If the coroutine is already in
348	and return false.	415	the ready queue, do nothing and return false.
		416
		417	This ensures that the scheduler will resume this coroutine automatically
		418	once all the coroutines of higher priority and all coroutines of the same
		419	priority that were put into the ready queue earlier have been resumed.
349		420
350	=item $is_ready = $coroutine->is_ready	421	=item $is_ready = $coroutine->is_ready
351		422
352	Return wether the coroutine is currently the ready queue or not,	423	Return whether the coroutine is currently the ready queue or not,
353		424
354	=item $coroutine->cancel (arg...)	425	=item $coroutine->cancel (arg...)
355		426
356	Terminates the given coroutine and makes it return the given arguments as	427	Terminates the given coroutine and makes it return the given arguments as
357	status (default: the empty list). Never returns if the coroutine is the	428	status (default: the empty list). Never returns if the coroutine is the
…		…
359		430
360	=cut	431	=cut
361		432
362	sub cancel {	433	sub cancel {
363	my $self = shift;	434	my $self = shift;
364	$self->{status} = [@_];	435	$self->{_status} = [@_];
365		436
366	if ($current == $self) {	437	if ($current == $self) {
367	push @destroy, $self;	438	push @destroy, $self;
368	$manager->ready;	439	$manager->ready;
369	&schedule while 1;	440	&schedule while 1;
370	} else {	441	} else {
371	$self->_cancel;	442	$self->_cancel;
372	}	443	}
373	}	444	}
374		445
		446	=item $coroutine->throw ([$scalar])
		447
		448	If C<$throw> is specified and defined, it will be thrown as an exception
		449	inside the coroutine at the next convenient point in time (usually after
		450	it gains control at the next schedule/transfer/cede). Otherwise clears the
		451	exception object.
		452
		453	The exception object will be thrown "as is" with the specified scalar in
		454	C<$@>, i.e. if it is a string, no line number or newline will be appended
		455	(unlike with C<die>).
		456
		457	This can be used as a softer means than C<cancel> to ask a coroutine to
		458	end itself, although there is no guarantee that the exception will lead to
		459	termination, and if the exception isn't caught it might well end the whole
		460	program.
		461
		462	You might also think of C<throw> as being the moral equivalent of
		463	C<kill>ing a coroutine with a signal (in this case, a scalar).
		464
375	=item $coroutine->join	465	=item $coroutine->join
376		466
377	Wait until the coroutine terminates and return any values given to the	467	Wait until the coroutine terminates and return any values given to the
378	C<terminate> or C<cancel> functions. C<join> can be called multiple times	468	C<terminate> or C<cancel> functions. C<join> can be called concurrently
379	from multiple coroutine.	469	from multiple coroutines, and all will be resumed and given the status
		470	return once the C<$coroutine> terminates.
380		471
381	=cut	472	=cut
382		473
383	sub join {	474	sub join {
384	my $self = shift;	475	my $self = shift;
385		476
386	unless ($self->{status}) {	477	unless ($self->{_status}) {
387	my $current = $current;	478	my $current = $current;
388		479
389	push @{$self->{destroy_cb}}, sub {	480	push @{$self->{_on_destroy}}, sub {
390	$current->ready;	481	$current->ready;
391	undef $current;	482	undef $current;
392	};	483	};
393		484
394	&schedule while $current;	485	&schedule while $current;
395	}	486	}
396		487
397	wantarray ? @{$self->{status}} : $self->{status}[0];	488	wantarray ? @{$self->{_status}} : $self->{_status}[0];
398	}	489	}
399		490
400	=item $coroutine->on_destroy (\&cb)	491	=item $coroutine->on_destroy (\&cb)
401		492
402	Registers a callback that is called when this coroutine gets destroyed,	493	Registers a callback that is called when this coroutine gets destroyed,
403	but before it is joined. The callback gets passed the terminate arguments,	494	but before it is joined. The callback gets passed the terminate arguments,
404	if any.	495	if any, and I<must not> die, under any circumstances.
405		496
406	=cut	497	=cut
407		498
408	sub on_destroy {	499	sub on_destroy {
409	my ($self, $cb) = @_;	500	my ($self, $cb) = @_;
410		501
411	push @{ $self->{destroy_cb} }, $cb;	502	push @{ $self->{_on_destroy} }, $cb;
412	}	503	}
413		504
414	=item $oldprio = $coroutine->prio ($newprio)	505	=item $oldprio = $coroutine->prio ($newprio)
415		506
416	Sets (or gets, if the argument is missing) the priority of the	507	Sets (or gets, if the argument is missing) the priority of the
…		…
439	higher values mean lower priority, just as in unix).	530	higher values mean lower priority, just as in unix).
440		531
441	=item $olddesc = $coroutine->desc ($newdesc)	532	=item $olddesc = $coroutine->desc ($newdesc)
442		533
443	Sets (or gets in case the argument is missing) the description for this	534	Sets (or gets in case the argument is missing) the description for this
444	coroutine. This is just a free-form string you can associate with a coroutine.	535	coroutine. This is just a free-form string you can associate with a
		536	coroutine.
		537
		538	This method simply sets the C<< $coroutine->{desc} >> member to the given
		539	string. You can modify this member directly if you wish.
445		540
446	=cut	541	=cut
447		542
448	sub desc {	543	sub desc {
449	my $old = $_[0]{desc};	544	my $old = $_[0]{desc};
…		…
458	=over 4	553	=over 4
459		554
460	=item Coro::nready	555	=item Coro::nready
461		556
462	Returns the number of coroutines that are currently in the ready state,	557	Returns the number of coroutines that are currently in the ready state,
463	i.e. that can be swicthed to. The value C<0> means that the only runnable	558	i.e. that can be switched to by calling C<schedule> directory or
		559	indirectly. The value C<0> means that the only runnable coroutine is the
464	coroutine is the currently running one, so C<cede> would have no effect,	560	currently running one, so C<cede> would have no effect, and C<schedule>
465	and C<schedule> would cause a deadlock unless there is an idle handler	561	would cause a deadlock unless there is an idle handler that wakes up some
466	that wakes up some coroutines.	562	coroutines.
467		563
468	=item my $guard = Coro::guard { ... }	564	=item my $guard = Coro::guard { ... }
469		565
470	This creates and returns a guard object. Nothing happens until the objetc	566	This creates and returns a guard object. Nothing happens until the object
471	gets destroyed, in which case the codeblock given as argument will be	567	gets destroyed, in which case the codeblock given as argument will be
472	executed. This is useful to free locks or other resources in case of a	568	executed. This is useful to free locks or other resources in case of a
473	runtime error or when the coroutine gets canceled, as in both cases the	569	runtime error or when the coroutine gets canceled, as in both cases the
474	guard block will be executed. The guard object supports only one method,	570	guard block will be executed. The guard object supports only one method,
475	C<< ->cancel >>, which will keep the codeblock from being executed.	571	C<< ->cancel >>, which will keep the codeblock from being executed.
…		…
500		596
501		597
502	=item unblock_sub { ... }	598	=item unblock_sub { ... }
503		599
504	This utility function takes a BLOCK or code reference and "unblocks" it,	600	This utility function takes a BLOCK or code reference and "unblocks" it,
505	returning the new coderef. This means that the new coderef will return	601	returning a new coderef. Unblocking means that calling the new coderef
506	immediately without blocking, returning nothing, while the original code	602	will return immediately without blocking, returning nothing, while the
507	ref will be called (with parameters) from within its own coroutine.	603	original code ref will be called (with parameters) from within another
		604	coroutine.
508		605
509	The reason this fucntion exists is that many event libraries (such as the	606	The reason this function exists is that many event libraries (such as the
510	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	607	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
511	of thread-safety). This means you must not block within event callbacks,	608	of thread-safety). This means you must not block within event callbacks,
512	otherwise you might suffer from crashes or worse.	609	otherwise you might suffer from crashes or worse. The only event library
		610	currently known that is safe to use without C<unblock_sub> is L<EV>.
513		611
514	This function allows your callbacks to block by executing them in another	612	This function allows your callbacks to block by executing them in another
515	coroutine where it is safe to block. One example where blocking is handy	613	coroutine where it is safe to block. One example where blocking is handy
516	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to	614	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
517	disk.	615	disk, for example.
518		616
519	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	617	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
520	creating event callbacks that want to block.	618	creating event callbacks that want to block.
		619
		620	If your handler does not plan to block (e.g. simply sends a message to
		621	another coroutine, or puts some other coroutine into the ready queue),
		622	there is no reason to use C<unblock_sub>.
		623
		624	Note that you also need to use C<unblock_sub> for any other callbacks that
		625	are indirectly executed by any C-based event loop. For example, when you
		626	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		627	provides callbacks that are the result of some event callback, then you
		628	must not block either, or use C<unblock_sub>.
521		629
522	=cut	630	=cut
523		631
524	our @unblock_queue;	632	our @unblock_queue;
525		633
526	# we create a special coro because we want to cede,	634	# we create a special coro because we want to cede,
527	# to reduce pressure on the coro pool (because most callbacks	635	# to reduce pressure on the coro pool (because most callbacks
528	# return immediately and can be reused) and because we cannot cede	636	# return immediately and can be reused) and because we cannot cede
529	# inside an event callback.	637	# inside an event callback.
530	our $unblock_scheduler = async {	638	our $unblock_scheduler = new Coro sub {
531	while () {	639	while () {
532	while (my $cb = pop @unblock_queue) {	640	while (my $cb = pop @unblock_queue) {
533	# this is an inlined copy of async_pool	641	# this is an inlined copy of async_pool
534	my $coro = (pop @pool or new Coro \&pool_handler);	642	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
535		643
536	$coro->{_invoke} = $cb;	644	$coro->{_invoke} = $cb;
537	$coro->ready;	645	$coro->ready;
538	cede; # for short-lived callbacks, this reduces pressure on the coro pool	646	cede; # for short-lived callbacks, this reduces pressure on the coro pool
539	}	647	}
540	schedule; # sleep well	648	schedule; # sleep well
541	}	649	}
542	};	650	};
		651	$unblock_scheduler->{desc} = "[unblock_sub scheduler]";
543		652
544	sub unblock_sub(&) {	653	sub unblock_sub(&) {
545	my $cb = shift;	654	my $cb = shift;
546		655
547	sub {	656	sub {
…		…
556		665
557	1;	666	1;
558		667
559	=head1 BUGS/LIMITATIONS	668	=head1 BUGS/LIMITATIONS
560		669
561	- you must make very sure that no coro is still active on global	670	=over 4
562	destruction. very bad things might happen otherwise (usually segfaults).
563		671
		672	=item perl process emulation ("threads")
		673
564	- this module is not thread-safe. You should only ever use this module	674	This module is not perl-pseudo-thread-safe. You should only ever use this
565	from the same thread (this requirement might be losened in the future	675	module from the same thread (this requirement might be removed in the
566	to allow per-thread schedulers, but Coro::State does not yet allow	676	future to allow per-thread schedulers, but Coro::State does not yet allow
567	this).	677	this). I recommend disabling thread support and using processes, as having
		678	the windows process emulation enabled under unix roughly halves perl
		679	performance, even when not used.
		680
		681	=item coroutine switching not signal safe
		682
		683	You must not switch to another coroutine from within a signal handler
		684	(only relevant with %SIG - most event libraries provide safe signals).
		685
		686	That means you I<MUST NOT> call any fucntion that might "block" the
		687	current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
		688	anything that calls those. Everything else, including calling C<ready>,
		689	works.
		690
		691	=back
		692
568		693
569	=head1 SEE ALSO	694	=head1 SEE ALSO
570		695
		696	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		697
		698	Debugging: L<Coro::Debug>.
		699
571	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	700	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
572		701
573	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	702	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
574		703
575	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	704	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
576		705
577	Embedding: L<Coro:MakeMaker>	706	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		707
		708	XS API: L<Coro::MakeMaker>.
		709
		710	Low level Configuration, Coroutine Environment: L<Coro::State>.
578		711
579	=head1 AUTHOR	712	=head1 AUTHOR
580		713
581	Marc Lehmann <schmorp@schmorp.de>	714	Marc Lehmann <schmorp@schmorp.de>
582	http://home.schmorp.de/	715	http://home.schmorp.de/

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Comparing Coro/Coro.pm (file contents): Revision 1.114 by root, Wed Jan 24 16:22:08 2007 UTC vs. Revision 1.217 by root, Fri Nov 14 23:48:10 2008 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.114 by root, Wed Jan 24 16:22:08 2007 UTC vs.
Revision 1.217 by root, Fri Nov 14 23:48:10 2008 UTC