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

Comparing Coro/Coro.pm (file contents):
Revision 1.121 by root, Fri Apr 13 12:56:55 2007 UTC vs.
Revision 1.195 by root, Wed Jul 23 22:15:25 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	my $lock = new Coro::Semaphore;
19	cede;	22	my $locked;
		23
		24	$lock->down;
		25	$locked = 1;
		26	$lock->up;
20		27
21	=head1 DESCRIPTION	28	=head1 DESCRIPTION
22		29
23	This module collection manages coroutines. Coroutines are similar	30	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	31	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	32	on SMP machines. The specific flavor of coroutine used in this module
26	guarentees you that it will not switch between coroutines unless	33	also guarantees you that it will not switch between coroutines unless
27	necessary, at easily-identified points in your program, so locking and	34	necessary, at easily-identified points in your program, so locking and
28	parallel access are rarely an issue, making coroutine programming much	35	parallel access are rarely an issue, making coroutine programming much
29	safer than threads programming.	36	safer and easier than threads programming.
30		37
31	(Perl, however, does not natively support real threads but instead does a	38	Unlike a normal perl program, however, coroutines allow you to have
32	very slow and memory-intensive emulation of processes using threads. This	39	multiple running interpreters that share data, which is especially useful
33	is a performance win on Windows machines, and a loss everywhere else).	40	to code pseudo-parallel processes and for event-based programming, such as
		41	multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to
		42	learn more.
		43
		44	Coroutines are also useful because Perl has no support for threads (the so
		45	called "threads" that perl offers are nothing more than the (bad) process
		46	emulation coming from the Windows platform: On standard operating systems
		47	they serve no purpose whatsoever, except by making your programs slow and
		48	making them use a lot of memory. Best disable them when building perl, or
		49	aks your software vendor/distributor to do it for you).
34		50
35	In this module, coroutines are defined as "callchain + lexical variables +	51	In this module, coroutines are defined as "callchain + lexical variables +
36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,	52	@_ + $_ + $@ + $/ + 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	53	its own set of lexicals and its own set of perls most important global
38	variables.	54	variables (see L<Coro::State> for more configuration).
39		55
40	=cut	56	=cut
41		57
42	package Coro;	58	package Coro;
43		59
…		…
50		66
51	our $idle; # idle handler	67	our $idle; # idle handler
52	our $main; # main coroutine	68	our $main; # main coroutine
53	our $current; # current coroutine	69	our $current; # current coroutine
54		70
55	our $VERSION = '3.56';	71	our $VERSION = 4.745;
56		72
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	73	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	74	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	75	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	76	);
61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	77	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62		78
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	79	=over 4
98		80
99	=item $main	81	=item $Coro::main
100		82
101	This coroutine represents the main program.	83	This variable stores the coroutine object that represents the main
		84	program. While you cna C<ready> it and do most other things you can do to
		85	coroutines, it is mainly useful to compare again C<$Coro::current>, to see
		86	wether you are running in the main program or not.
102		87
103	=cut	88	=cut
104		89
105	$main = new Coro;	90	$main = new Coro;
106		91
107	=item $current (or as function: current)	92	=item $Coro::current
108		93
109	The current coroutine (the last coroutine switched to). The initial value	94	The coroutine object representing the current coroutine (the last
		95	coroutine that the Coro scheduler switched to). The initial value is
110	is C<$main> (of course).	96	C<$main> (of course).
111		97
112	This variable is B<strictly> I<read-only>. It is provided for performance	98	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	99	value stored in it and use it as any other coroutine object, but you must
114	C<Coro::current> function instead.	100	not otherwise modify the variable itself.
115		101
116	=cut	102	=cut
		103
		104	$main->{desc} = "[main::]";
117		105
118	# maybe some other module used Coro::Specific before...	106	# maybe some other module used Coro::Specific before...
119	$main->{specific} = $current->{specific}	107	$main->{_specific} = $current->{_specific}
120	if $current;	108	if $current;
121		109
122	_set_current $main;	110	_set_current $main;
123		111
124	sub current() { $current }	112	sub current() { $current } # [DEPRECATED]
125		113
126	=item $idle	114	=item $Coro::idle
127		115
128	A callback that is called whenever the scheduler finds no ready coroutines	116	This variable is mainly useful to integrate Coro into event loops. It is
129	to run. The default implementation prints "FATAL: deadlock detected" and	117	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.	118	pretty low-level functionality.
		119
		120	This variable stores a callback that is called whenever the scheduler
		121	finds no ready coroutines to run. The default implementation prints
		122	"FATAL: deadlock detected" and exits, because the program has no other way
		123	to continue.
131		124
132	This hook is overwritten by modules such as C<Coro::Timer> and	125	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	126	C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
134	coroutine so the scheduler can run it.	127	coroutine so the scheduler can run it.
135		128
		129	Note that the callback I<must not>, under any circumstances, block
		130	the current coroutine. Normally, this is achieved by having an "idle
		131	coroutine" that calls the event loop and then blocks again, and then
		132	readying that coroutine in the idle handler.
		133
		134	See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
		135	technique.
		136
136	Please note that if your callback recursively invokes perl (e.g. for event	137	Please note that if your callback recursively invokes perl (e.g. for event
137	handlers), then it must be prepared to be called recursively.	138	handlers), then it must be prepared to be called recursively itself.
138		139
139	=cut	140	=cut
140		141
141	$idle = sub {	142	$idle = sub {
142	require Carp;	143	require Carp;
…		…
149	# free coroutine data and mark as destructed	150	# free coroutine data and mark as destructed
150	$self->_destroy	151	$self->_destroy
151	or return;	152	or return;
152		153
153	# call all destruction callbacks	154	# call all destruction callbacks
154	$_->(@{$self->{status}})	155	$_->(@{$self->{_status}})
155	for @{(delete $self->{destroy_cb}) \|\| []};	156	for @{(delete $self->{_on_destroy}) \|\| []};
156	}	157	}
157		158
158	# this coroutine is necessary because a coroutine	159	# this coroutine is necessary because a coroutine
159	# cannot destroy itself.	160	# cannot destroy itself.
160	my @destroy;	161	my @destroy;
…		…
166	while @destroy;	167	while @destroy;
167		168
168	&schedule;	169	&schedule;
169	}	170	}
170	};	171	};
171		172	$manager->desc ("[coro manager]");
172	$manager->prio (PRIO_MAX);	173	$manager->prio (PRIO_MAX);
173		174
174	# static methods. not really.
175
176	=back	175	=back
177		176
178	=head2 STATIC METHODS	177	=head2 SIMPLE COROUTINE CREATION
179
180	Static methods are actually functions that operate on the current coroutine only.
181		178
182	=over 4	179	=over 4
183		180
184	=item async { ... } [@args...]	181	=item async { ... } [@args...]
185		182
186	Create a new asynchronous coroutine and return it's coroutine object	183	Create a new coroutine and return it's coroutine object (usually
187	(usually unused). When the sub returns the new coroutine is automatically	184	unused). The coroutine will be put into the ready queue, so
		185	it will start running automatically on the next scheduler run.
		186
		187	The first argument is a codeblock/closure that should be executed in the
		188	coroutine. When it returns argument returns the coroutine is automatically
188	terminated.	189	terminated.
189		190
		191	The remaining arguments are passed as arguments to the closure.
		192
		193	See the C<Coro::State::new> constructor for info about the coroutine
		194	environment in which coroutines are executed.
		195
190	Calling C<exit> in a coroutine will try to do the same as calling exit	196	Calling C<exit> in a coroutine will do the same as calling exit outside
191	outside the coroutine, but this is experimental. It is best not to rely on	197	the coroutine. Likewise, when the coroutine dies, the program will exit,
192	exit doing any cleanups or even not crashing.	198	just as it would in the main program.
193		199
194	When the coroutine dies, the program will exit, just as in the main	200	If you do not want that, you can provide a default C<die> handler, or
195	program.	201	simply avoid dieing (by use of C<eval>).
196		202
197	# create a new coroutine that just prints its arguments	203	Example: Create a new coroutine that just prints its arguments.
		204
198	async {	205	async {
199	print "@_\n";	206	print "@_\n";
200	} 1,2,3,4;	207	} 1,2,3,4;
201		208
202	=cut	209	=cut
…		…
208	}	215	}
209		216
210	=item async_pool { ... } [@args...]	217	=item async_pool { ... } [@args...]
211		218
212	Similar to C<async>, but uses a coroutine pool, so you should not call	219	Similar to C<async>, but uses a coroutine pool, so you should not call
213	terminate or join (although you are allowed to), and you get a coroutine	220	terminate or join on it (although you are allowed to), and you get a
214	that might have executed other code already (which can be good or bad :).	221	coroutine that might have executed other code already (which can be good
		222	or bad :).
215		223
		224	On the plus side, this function is faster than creating (and destroying)
		225	a completely new coroutine, so if you need a lot of generic coroutines in
		226	quick successsion, use C<async_pool>, not C<async>.
		227
216	Also, the block is executed in an C<eval> context and a warning will be	228	The code block is executed in an C<eval> context and a warning will be
217	issued in case of an exception instead of terminating the program, as	229	issued in case of an exception instead of terminating the program, as
218	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>	230	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
219	will not work in the expected way, unless you call terminate or cancel,	231	will not work in the expected way, unless you call terminate or cancel,
220	which somehow defeats the purpose of pooling.	232	which somehow defeats the purpose of pooling (but is fine in the
		233	exceptional case).
221		234
222	The priority will be reset to C<0> after each job, otherwise the coroutine	235	The priority will be reset to C<0> after each run, tracing will be
223	will be re-used "as-is".	236	disabled, the description will be reset and the default output filehandle
		237	gets restored, so you can change all these. Otherwise the coroutine will
		238	be re-used "as-is": most notably if you change other per-coroutine global
		239	stuff such as C<$/> you I<must needs> to revert that change, which is most
		240	simply done by using local as in: C< local $/ >.
224		241
225	The pool size is limited to 8 idle coroutines (this can be adjusted by	242	The pool size is limited to C<8> idle coroutines (this can be adjusted by
226	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as	243	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
227	required.	244	required.
228		245
229	If you are concerned about pooled coroutines growing a lot because a	246	If you are concerned about pooled coroutines growing a lot because a
230	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {	247	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
231	terminate }> once per second or so to slowly replenish the pool.	248	{ terminate }> once per second or so to slowly replenish the pool. In
		249	addition to that, when the stacks used by a handler grows larger than 16kb
		250	(adjustable via $Coro::POOL_RSS) it will also be destroyed.
232		251
233	=cut	252	=cut
234		253
235	our $POOL_SIZE = 8;	254	our $POOL_SIZE = 8;
		255	our $POOL_RSS = 16 * 1024;
236	our @pool;	256	our @async_pool;
237		257
238	sub pool_handler {	258	sub pool_handler {
		259	my $cb;
		260
239	while () {	261	while () {
240	eval {	262	eval {
241	my ($cb, @arg) = @{ delete $current->{_invoke} or return };	263	while () {
242	$cb->(@arg);	264	_pool_1 $cb;
		265	&$cb;
		266	_pool_2 $cb;
		267	&schedule;
		268	}
243	};	269	};
		270
		271	if ($@) {
		272	last if $@ eq "\3async_pool terminate\2\n";
244	warn $@ if $@;	273	warn $@;
245		274	}
246	last if @pool >= $POOL_SIZE;
247	push @pool, $current;
248
249	$current->save (Coro::State::SAVE_DEF);
250	$current->prio (0);
251	schedule;
252	}	275	}
253	}	276	}
254		277
255	sub async_pool(&@) {	278	sub async_pool(&@) {
256	# this is also inlined into the unlock_scheduler	279	# this is also inlined into the unlock_scheduler
257	my $coro = (pop @pool or new Coro \&pool_handler);	280	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
258		281
259	$coro->{_invoke} = [@_];	282	$coro->{_invoke} = [@_];
260	$coro->ready;	283	$coro->ready;
261		284
262	$coro	285	$coro
263	}	286	}
264		287
		288	=back
		289
		290	=head2 STATIC METHODS
		291
		292	Static methods are actually functions that operate on the current coroutine.
		293
		294	=over 4
		295
265	=item schedule	296	=item schedule
266		297
267	Calls the scheduler. Please note that the current coroutine will not be put	298	Calls the scheduler. The scheduler will find the next coroutine that is
		299	to be run from the ready queue and switches to it. The next coroutine
		300	to be run is simply the one with the highest priority that is longest
		301	in its ready queue. If there is no coroutine ready, it will clal the
		302	C<$Coro::idle> hook.
		303
		304	Please note that the current coroutine will I<not> be put into the ready
268	into the ready queue, so calling this function usually means you will	305	queue, so calling this function usually means you will never be called
269	never be called again unless something else (e.g. an event handler) calls	306	again unless something else (e.g. an event handler) calls C<< ->ready >>,
270	ready.	307	thus waking you up.
		308
		309	This makes C<schedule> I<the> generic method to use to block the current
		310	coroutine and wait for events: first you remember the current coroutine in
		311	a variable, then arrange for some callback of yours to call C<< ->ready
		312	>> on that once some event happens, and last you call C<schedule> to put
		313	yourself to sleep. Note that a lot of things can wake your coroutine up,
		314	so you need to check wether the event indeed happened, e.g. by storing the
		315	status in a variable.
271		316
272	The canonical way to wait on external events is this:	317	The canonical way to wait on external events is this:
273		318
274	{	319	{
275	# remember current coroutine	320	# remember current coroutine
…		…
280	# wake up sleeping coroutine	325	# wake up sleeping coroutine
281	$current->ready;	326	$current->ready;
282	undef $current;	327	undef $current;
283	};	328	};
284		329
285	# call schedule until event occured.	330	# call schedule until event occurred.
286	# in case we are woken up for other reasons	331	# in case we are woken up for other reasons
287	# (current still defined), loop.	332	# (current still defined), loop.
288	Coro::schedule while $current;	333	Coro::schedule while $current;
289	}	334	}
290		335
291	=item cede	336	=item cede
292		337
293	"Cede" to other coroutines. This function puts the current coroutine into the	338	"Cede" to other coroutines. This function puts the current coroutine into
294	ready queue and calls C<schedule>, which has the effect of giving up the	339	the ready queue and calls C<schedule>, which has the effect of giving
295	current "timeslice" to other coroutines of the same or higher priority.	340	up the current "timeslice" to other coroutines of the same or higher
		341	priority. Once your coroutine gets its turn again it will automatically be
		342	resumed.
296		343
297	Returns true if at least one coroutine switch has happened.	344	This function is often called C<yield> in other languages.
298		345
299	=item Coro::cede_notself	346	=item Coro::cede_notself
300		347
301	Works like cede, but is not exported by default and will cede to any	348	Works like cede, but is not exported by default and will cede to I<any>
302	coroutine, regardless of priority, once.	349	coroutine, regardless of priority. This is useful sometimes to ensure
303		350	progress is made.
304	Returns true if at least one coroutine switch has happened.
305		351
306	=item terminate [arg...]	352	=item terminate [arg...]
307		353
308	Terminates the current coroutine with the given status values (see L<cancel>).	354	Terminates the current coroutine with the given status values (see L<cancel>).
		355
		356	=item killall
		357
		358	Kills/terminates/cancels all coroutines except the currently running
		359	one. This is useful after a fork, either in the child or the parent, as
		360	usually only one of them should inherit the running coroutines.
		361
		362	Note that while this will try to free some of the main programs resources,
		363	you cnanot free all of them, so if a coroutine that is not the main
		364	program calls this function, there will be some one-time resource leak.
309		365
310	=cut	366	=cut
311		367
312	sub terminate {	368	sub terminate {
313	$current->cancel (@_);	369	$current->cancel (@_);
314	}	370	}
315		371
		372	sub killall {
		373	for (Coro::State::list) {
		374	$_->cancel
		375	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		376	}
		377	}
		378
316	=back	379	=back
317		380
318	# dynamic methods
319
320	=head2 COROUTINE METHODS	381	=head2 COROUTINE METHODS
321		382
322	These are the methods you can call on coroutine objects.	383	These are the methods you can call on coroutine objects (or to create
		384	them).
323		385
324	=over 4	386	=over 4
325		387
326	=item new Coro \&sub [, @args...]	388	=item new Coro \&sub [, @args...]
327		389
328	Create a new coroutine and return it. When the sub returns the coroutine	390	Create a new coroutine and return it. When the sub returns, the coroutine
329	automatically terminates as if C<terminate> with the returned values were	391	automatically terminates as if C<terminate> with the returned values were
330	called. To make the coroutine run you must first put it into the ready queue	392	called. To make the coroutine run you must first put it into the ready
331	by calling the ready method.	393	queue by calling the ready method.
332		394
333	See C<async> for additional discussion.	395	See C<async> and C<Coro::State::new> for additional info about the
		396	coroutine environment.
334		397
335	=cut	398	=cut
336		399
337	sub _run_coro {	400	sub _run_coro {
338	terminate &{+shift};	401	terminate &{+shift};
…		…
344	$class->SUPER::new (\&_run_coro, @_)	407	$class->SUPER::new (\&_run_coro, @_)
345	}	408	}
346		409
347	=item $success = $coroutine->ready	410	=item $success = $coroutine->ready
348		411
349	Put the given coroutine into the ready queue (according to it's priority)	412	Put the given coroutine into the end of its ready queue (there is one
350	and return true. If the coroutine is already in the ready queue, do nothing	413	queue for each priority) and return true. If the coroutine is already in
351	and return false.	414	the ready queue, do nothing and return false.
		415
		416	This ensures that the scheduler will resume this coroutine automatically
		417	once all the coroutines of higher priority and all coroutines of the same
		418	priority that were put into the ready queue earlier have been resumed.
352		419
353	=item $is_ready = $coroutine->is_ready	420	=item $is_ready = $coroutine->is_ready
354		421
355	Return wether the coroutine is currently the ready queue or not,	422	Return wether the coroutine is currently the ready queue or not,
356		423
…		…
362		429
363	=cut	430	=cut
364		431
365	sub cancel {	432	sub cancel {
366	my $self = shift;	433	my $self = shift;
367	$self->{status} = [@_];	434	$self->{_status} = [@_];
368		435
369	if ($current == $self) {	436	if ($current == $self) {
370	push @destroy, $self;	437	push @destroy, $self;
371	$manager->ready;	438	$manager->ready;
372	&schedule while 1;	439	&schedule while 1;
…		…
376	}	443	}
377		444
378	=item $coroutine->join	445	=item $coroutine->join
379		446
380	Wait until the coroutine terminates and return any values given to the	447	Wait until the coroutine terminates and return any values given to the
381	C<terminate> or C<cancel> functions. C<join> can be called multiple times	448	C<terminate> or C<cancel> functions. C<join> can be called concurrently
382	from multiple coroutine.	449	from multiple coroutines, and all will be resumed and given the status
		450	return once the C<$coroutine> terminates.
383		451
384	=cut	452	=cut
385		453
386	sub join {	454	sub join {
387	my $self = shift;	455	my $self = shift;
388		456
389	unless ($self->{status}) {	457	unless ($self->{_status}) {
390	my $current = $current;	458	my $current = $current;
391		459
392	push @{$self->{destroy_cb}}, sub {	460	push @{$self->{_on_destroy}}, sub {
393	$current->ready;	461	$current->ready;
394	undef $current;	462	undef $current;
395	};	463	};
396		464
397	&schedule while $current;	465	&schedule while $current;
398	}	466	}
399		467
400	wantarray ? @{$self->{status}} : $self->{status}[0];	468	wantarray ? @{$self->{_status}} : $self->{_status}[0];
401	}	469	}
402		470
403	=item $coroutine->on_destroy (\&cb)	471	=item $coroutine->on_destroy (\&cb)
404		472
405	Registers a callback that is called when this coroutine gets destroyed,	473	Registers a callback that is called when this coroutine gets destroyed,
406	but before it is joined. The callback gets passed the terminate arguments,	474	but before it is joined. The callback gets passed the terminate arguments,
407	if any.	475	if any, and I<must not> die, under any circumstances.
408		476
409	=cut	477	=cut
410		478
411	sub on_destroy {	479	sub on_destroy {
412	my ($self, $cb) = @_;	480	my ($self, $cb) = @_;
413		481
414	push @{ $self->{destroy_cb} }, $cb;	482	push @{ $self->{_on_destroy} }, $cb;
415	}	483	}
416		484
417	=item $oldprio = $coroutine->prio ($newprio)	485	=item $oldprio = $coroutine->prio ($newprio)
418		486
419	Sets (or gets, if the argument is missing) the priority of the	487	Sets (or gets, if the argument is missing) the priority of the
…		…
444	=item $olddesc = $coroutine->desc ($newdesc)	512	=item $olddesc = $coroutine->desc ($newdesc)
445		513
446	Sets (or gets in case the argument is missing) the description for this	514	Sets (or gets in case the argument is missing) the description for this
447	coroutine. This is just a free-form string you can associate with a coroutine.	515	coroutine. This is just a free-form string you can associate with a coroutine.
448		516
		517	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		518	can modify this member directly if you wish.
		519
		520	=item $coroutine->throw ([$scalar])
		521
		522	If C<$throw> is specified and defined, it will be thrown as an exception
		523	inside the coroutine at the next convinient point in time (usually after
		524	it gains control at the next schedule/transfer/cede). Otherwise clears the
		525	exception object.
		526
		527	The exception object will be thrown "as is" with the specified scalar in
		528	C<$@>, i.e. if it is a string, no line number or newline will be appended
		529	(unlike with C<die>).
		530
		531	This can be used as a softer means than C<cancel> to ask a coroutine to
		532	end itself, although there is no guarentee that the exception will lead to
		533	termination, and if the exception isn't caught it might well end the whole
		534	program.
		535
449	=cut	536	=cut
450		537
451	sub desc {	538	sub desc {
452	my $old = $_[0]{desc};	539	my $old = $_[0]{desc};
453	$_[0]{desc} = $_[1] if @_ > 1;	540	$_[0]{desc} = $_[1] if @_ > 1;
…		…
461	=over 4	548	=over 4
462		549
463	=item Coro::nready	550	=item Coro::nready
464		551
465	Returns the number of coroutines that are currently in the ready state,	552	Returns the number of coroutines that are currently in the ready state,
466	i.e. that can be swicthed to. The value C<0> means that the only runnable	553	i.e. that can be switched to by calling C<schedule> directory or
		554	indirectly. The value C<0> means that the only runnable coroutine is the
467	coroutine is the currently running one, so C<cede> would have no effect,	555	currently running one, so C<cede> would have no effect, and C<schedule>
468	and C<schedule> would cause a deadlock unless there is an idle handler	556	would cause a deadlock unless there is an idle handler that wakes up some
469	that wakes up some coroutines.	557	coroutines.
470		558
471	=item my $guard = Coro::guard { ... }	559	=item my $guard = Coro::guard { ... }
472		560
473	This creates and returns a guard object. Nothing happens until the object	561	This creates and returns a guard object. Nothing happens until the object
474	gets destroyed, in which case the codeblock given as argument will be	562	gets destroyed, in which case the codeblock given as argument will be
…		…
503		591
504		592
505	=item unblock_sub { ... }	593	=item unblock_sub { ... }
506		594
507	This utility function takes a BLOCK or code reference and "unblocks" it,	595	This utility function takes a BLOCK or code reference and "unblocks" it,
508	returning the new coderef. This means that the new coderef will return	596	returning a new coderef. Unblocking means that calling the new coderef
509	immediately without blocking, returning nothing, while the original code	597	will return immediately without blocking, returning nothing, while the
510	ref will be called (with parameters) from within its own coroutine.	598	original code ref will be called (with parameters) from within another
		599	coroutine.
511		600
512	The reason this fucntion exists is that many event libraries (such as the	601	The reason this function exists is that many event libraries (such as the
513	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	602	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
514	of thread-safety). This means you must not block within event callbacks,	603	of thread-safety). This means you must not block within event callbacks,
515	otherwise you might suffer from crashes or worse.	604	otherwise you might suffer from crashes or worse. The only event library
		605	currently known that is safe to use without C<unblock_sub> is L<EV>.
516		606
517	This function allows your callbacks to block by executing them in another	607	This function allows your callbacks to block by executing them in another
518	coroutine where it is safe to block. One example where blocking is handy	608	coroutine where it is safe to block. One example where blocking is handy
519	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to	609	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
520	disk.	610	disk, for example.
521		611
522	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	612	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
523	creating event callbacks that want to block.	613	creating event callbacks that want to block.
		614
		615	If your handler does not plan to block (e.g. simply sends a message to
		616	another coroutine, or puts some other coroutine into the ready queue),
		617	there is no reason to use C<unblock_sub>.
		618
		619	Note that you also need to use C<unblock_sub> for any other callbacks that
		620	are indirectly executed by any C-based event loop. For example, when you
		621	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		622	provides callbacks that are the result of some event callback, then you
		623	must not block either, or use C<unblock_sub>.
524		624
525	=cut	625	=cut
526		626
527	our @unblock_queue;	627	our @unblock_queue;
528		628
529	# we create a special coro because we want to cede,	629	# we create a special coro because we want to cede,
530	# to reduce pressure on the coro pool (because most callbacks	630	# to reduce pressure on the coro pool (because most callbacks
531	# return immediately and can be reused) and because we cannot cede	631	# return immediately and can be reused) and because we cannot cede
532	# inside an event callback.	632	# inside an event callback.
533	our $unblock_scheduler = async {	633	our $unblock_scheduler = new Coro sub {
534	while () {	634	while () {
535	while (my $cb = pop @unblock_queue) {	635	while (my $cb = pop @unblock_queue) {
536	# this is an inlined copy of async_pool	636	# this is an inlined copy of async_pool
537	my $coro = (pop @pool or new Coro \&pool_handler);	637	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
538		638
539	$coro->{_invoke} = $cb;	639	$coro->{_invoke} = $cb;
540	$coro->ready;	640	$coro->ready;
541	cede; # for short-lived callbacks, this reduces pressure on the coro pool	641	cede; # for short-lived callbacks, this reduces pressure on the coro pool
542	}	642	}
543	schedule; # sleep well	643	schedule; # sleep well
544	}	644	}
545	};	645	};
		646	$unblock_scheduler->desc ("[unblock_sub scheduler]");
546		647
547	sub unblock_sub(&) {	648	sub unblock_sub(&) {
548	my $cb = shift;	649	my $cb = shift;
549		650
550	sub {	651	sub {
…		…
559		660
560	1;	661	1;
561		662
562	=head1 BUGS/LIMITATIONS	663	=head1 BUGS/LIMITATIONS
563		664
564	- you must make very sure that no coro is still active on global
565	destruction. very bad things might happen otherwise (usually segfaults).
566
567	- this module is not thread-safe. You should only ever use this module	665	This module is not perl-pseudo-thread-safe. You should only ever use this
568	from the same thread (this requirement might be losened in the future	666	module from the same thread (this requirement might be removed in the
569	to allow per-thread schedulers, but Coro::State does not yet allow	667	future to allow per-thread schedulers, but Coro::State does not yet allow
570	this).	668	this). I recommend disabling thread support and using processes, as this
		669	is much faster and uses less memory.
571		670
572	=head1 SEE ALSO	671	=head1 SEE ALSO
573		672
		673	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		674
		675	Debugging: L<Coro::Debug>.
		676
574	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	677	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
575		678
576	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	679	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
577		680
578	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	681	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
579		682
580	Embedding: L<Coro:MakeMaker>	683	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		684
		685	XS API: L<Coro::MakeMaker>.
		686
		687	Low level Configuration, Coroutine Environment: L<Coro::State>.
581		688
582	=head1 AUTHOR	689	=head1 AUTHOR
583		690
584	Marc Lehmann <schmorp@schmorp.de>	691	Marc Lehmann <schmorp@schmorp.de>
585	http://home.schmorp.de/	692	http://home.schmorp.de/

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Comparing Coro/Coro.pm (file contents): Revision 1.121 by root, Fri Apr 13 12:56:55 2007 UTC vs. Revision 1.195 by root, Wed Jul 23 22:15:25 2008 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.121 by root, Fri Apr 13 12:56:55 2007 UTC vs.
Revision 1.195 by root, Wed Jul 23 22:15:25 2008 UTC