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

Comparing Coro/Coro.pm (file contents):
Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs.
Revision 1.210 by root, Sat Nov 8 16:46:32 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
…		…
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 = '3.3';	72	our $VERSION = 4.9;
56		73
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	74	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	75	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	76	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	77	);
61	our @EXPORT_OK = (@{$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
…		…
203	my $coro = new Coro @_;	213	my $coro = new Coro @_;
204	$coro->ready;	214	$coro->ready;
205	$coro	215	$coro
206	}	216	}
207		217
		218	=item async_pool { ... } [@args...]
		219
		220	Similar to C<async>, but uses a coroutine pool, so you should not call
		221	terminate or join on it (although you are allowed to), and you get a
		222	coroutine that might have executed other code already (which can be good
		223	or bad :).
		224
		225	On the plus side, this function is faster than creating (and destroying)
		226	a completly new coroutine, so if you need a lot of generic coroutines in
		227	quick successsion, use C<async_pool>, not C<async>.
		228
		229	The code block is executed in an C<eval> context and a warning will be
		230	issued in case of an exception instead of terminating the program, as
		231	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		232	will not work in the expected way, unless you call terminate or cancel,
		233	which somehow defeats the purpose of pooling (but is fine in the
		234	exceptional case).
		235
		236	The priority will be reset to C<0> after each run, tracing will be
		237	disabled, the description will be reset and the default output filehandle
		238	gets restored, so you can change all these. Otherwise the coroutine will
		239	be re-used "as-is": most notably if you change other per-coroutine global
		240	stuff such as C<$/> you I<must needs> revert that change, which is most
		241	simply done by using local as in: C<< local $/ >>.
		242
		243	The idle pool size is limited to C<8> idle coroutines (this can be
		244	adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
		245	coros as required.
		246
		247	If you are concerned about pooled coroutines growing a lot because a
		248	single C<async_pool> used a lot of stackspace you can e.g. C<async_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.
		252
		253	=cut
		254
		255	our $POOL_SIZE = 8;
		256	our $POOL_RSS = 16 * 1024;
		257	our @async_pool;
		258
		259	sub pool_handler {
		260	my $cb;
		261
		262	while () {
		263	eval {
		264	while () {
		265	_pool_1 $cb;
		266	&$cb;
		267	_pool_2 $cb;
		268	&schedule;
		269	}
		270	};
		271
		272	if ($@) {
		273	last if $@ eq "\3async_pool terminate\2\n";
		274	warn $@;
		275	}
		276	}
		277	}
		278
		279	sub async_pool(&@) {
		280	# this is also inlined into the unlock_scheduler
		281	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		282
		283	$coro->{_invoke} = [@_];
		284	$coro->ready;
		285
		286	$coro
		287	}
		288
		289	=back
		290
		291	=head2 STATIC METHODS
		292
		293	Static methods are actually functions that operate on the current coroutine.
		294
		295	=over 4
		296
208	=item schedule	297	=item schedule
209		298
210	Calls the scheduler. Please note that the current coroutine will not be put	299	Calls the scheduler. The scheduler will find the next coroutine that is
		300	to be run from the ready queue and switches to it. The next coroutine
		301	to be run is simply the one with the highest priority that is longest
		302	in its ready queue. If there is no coroutine ready, it will clal the
		303	C<$Coro::idle> hook.
		304
		305	Please note that the current coroutine will I<not> be put into the ready
211	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
212	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 >>,
213	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.
214		317
215	The canonical way to wait on external events is this:	318	The canonical way to wait on external events is this:
216		319
217	{	320	{
218	# remember current coroutine	321	# remember current coroutine
…		…
223	# wake up sleeping coroutine	326	# wake up sleeping coroutine
224	$current->ready;	327	$current->ready;
225	undef $current;	328	undef $current;
226	};	329	};
227		330
228	# call schedule until event occured.	331	# call schedule until event occurred.
229	# in case we are woken up for other reasons	332	# in case we are woken up for other reasons
230	# (current still defined), loop.	333	# (current still defined), loop.
231	Coro::schedule while $current;	334	Coro::schedule while $current;
232	}	335	}
233		336
234	=item cede	337	=item cede
235		338
236	"Cede" to other coroutines. This function puts the current coroutine into the	339	"Cede" to other coroutines. This function puts the current coroutine into
237	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
238	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.
		344
		345	This function is often called C<yield> in other languages.
239		346
240	=item Coro::cede_notself	347	=item Coro::cede_notself
241		348
242	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>
243	coroutine, regardless of priority, once.	350	coroutine, regardless of priority. This is useful sometimes to ensure
		351	progress is made.
244		352
245	=item terminate [arg...]	353	=item terminate [arg...]
246		354
247	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.
248		366
249	=cut	367	=cut
250		368
251	sub terminate {	369	sub terminate {
252	$current->cancel (@_);	370	$current->cancel (@_);
253	}	371	}
254		372
		373	sub killall {
		374	for (Coro::State::list) {
		375	$_->cancel
		376	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		377	}
		378	}
		379
255	=back	380	=back
256		381
257	# dynamic methods
258
259	=head2 COROUTINE METHODS	382	=head2 COROUTINE METHODS
260		383
261	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).
262		386
263	=over 4	387	=over 4
264		388
265	=item new Coro \&sub [, @args...]	389	=item new Coro \&sub [, @args...]
266		390
267	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
268	automatically terminates as if C<terminate> with the returned values were	392	automatically terminates as if C<terminate> with the returned values were
269	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
270	by calling the ready method.	394	queue by calling the ready method.
271		395
272	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.
273		398
274	=cut	399	=cut
275		400
276	sub _run_coro {	401	sub _run_coro {
277	terminate &{+shift};	402	terminate &{+shift};
…		…
283	$class->SUPER::new (\&_run_coro, @_)	408	$class->SUPER::new (\&_run_coro, @_)
284	}	409	}
285		410
286	=item $success = $coroutine->ready	411	=item $success = $coroutine->ready
287		412
288	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
289	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
290	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.
291		420
292	=item $is_ready = $coroutine->is_ready	421	=item $is_ready = $coroutine->is_ready
293		422
294	Return wether the coroutine is currently the ready queue or not,	423	Return whether the coroutine is currently the ready queue or not,
295		424
296	=item $coroutine->cancel (arg...)	425	=item $coroutine->cancel (arg...)
297		426
298	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
299	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
…		…
301		430
302	=cut	431	=cut
303		432
304	sub cancel {	433	sub cancel {
305	my $self = shift;	434	my $self = shift;
306	$self->{status} = [@_];	435	$self->{_status} = [@_];
307		436
308	if ($current == $self) {	437	if ($current == $self) {
309	push @destroy, $self;	438	push @destroy, $self;
310	$manager->ready;	439	$manager->ready;
311	&schedule while 1;	440	&schedule while 1;
312	} else {	441	} else {
313	$self->_cancel;	442	$self->_cancel;
314	}	443	}
315	}	444	}
316		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
317	=item $coroutine->join	465	=item $coroutine->join
318		466
319	Wait until the coroutine terminates and return any values given to the	467	Wait until the coroutine terminates and return any values given to the
320	C<terminate> or C<cancel> functions. C<join> can be called multiple times	468	C<terminate> or C<cancel> functions. C<join> can be called concurrently
321	from multiple coroutine.	469	from multiple coroutines, and all will be resumed and given the status
		470	return once the C<$coroutine> terminates.
322		471
323	=cut	472	=cut
324		473
325	sub join {	474	sub join {
326	my $self = shift;	475	my $self = shift;
327		476
328	unless ($self->{status}) {	477	unless ($self->{_status}) {
329	my $current = $current;	478	my $current = $current;
330		479
331	push @{$self->{destroy_cb}}, sub {	480	push @{$self->{_on_destroy}}, sub {
332	$current->ready;	481	$current->ready;
333	undef $current;	482	undef $current;
334	};	483	};
335		484
336	&schedule while $current;	485	&schedule while $current;
337	}	486	}
338		487
339	wantarray ? @{$self->{status}} : $self->{status}[0];	488	wantarray ? @{$self->{_status}} : $self->{_status}[0];
340	}	489	}
341		490
342	=item $coroutine->on_destroy (\&cb)	491	=item $coroutine->on_destroy (\&cb)
343		492
344	Registers a callback that is called when this coroutine gets destroyed,	493	Registers a callback that is called when this coroutine gets destroyed,
345	but before it is joined. The callback gets passed the terminate arguments,	494	but before it is joined. The callback gets passed the terminate arguments,
346	if any.	495	if any, and I<must not> die, under any circumstances.
347		496
348	=cut	497	=cut
349		498
350	sub on_destroy {	499	sub on_destroy {
351	my ($self, $cb) = @_;	500	my ($self, $cb) = @_;
352		501
353	push @{ $self->{destroy_cb} }, $cb;	502	push @{ $self->{_on_destroy} }, $cb;
354	}	503	}
355		504
356	=item $oldprio = $coroutine->prio ($newprio)	505	=item $oldprio = $coroutine->prio ($newprio)
357		506
358	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
…		…
381	higher values mean lower priority, just as in unix).	530	higher values mean lower priority, just as in unix).
382		531
383	=item $olddesc = $coroutine->desc ($newdesc)	532	=item $olddesc = $coroutine->desc ($newdesc)
384		533
385	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
386	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.
387		540
388	=cut	541	=cut
389		542
390	sub desc {	543	sub desc {
391	my $old = $_[0]{desc};	544	my $old = $_[0]{desc};
…		…
400	=over 4	553	=over 4
401		554
402	=item Coro::nready	555	=item Coro::nready
403		556
404	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,
405	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
406	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>
407	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
408	that wakes up some coroutines.	562	coroutines.
409		563
410	=item my $guard = Coro::guard { ... }	564	=item my $guard = Coro::guard { ... }
411		565
412	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
413	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
414	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
415	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
416	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,
417	C<< ->cancel >>, which will keep the codeblock from being executed.	571	C<< ->cancel >>, which will keep the codeblock from being executed.
…		…
442		596
443		597
444	=item unblock_sub { ... }	598	=item unblock_sub { ... }
445		599
446	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,
447	returning the new coderef. This means that the new coderef will return	601	returning a new coderef. Unblocking means that calling the new coderef
448	immediately without blocking, returning nothing, while the original code	602	will return immediately without blocking, returning nothing, while the
449	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.
450		605
451	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
452	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
453	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,
454	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>.
455		611
456	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
457	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
458	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
459	disk.	615	disk, for example.
460		616
461	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
462	creating event callbacks that want to block.	618	creating event callbacks that want to block.
463		619
464	=cut	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>.
465		623
466	our @unblock_pool;	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>.
		629
		630	=cut
		631
467	our @unblock_queue;	632	our @unblock_queue;
468	our $UNBLOCK_POOL_SIZE = 2;
469		633
470	sub unblock_handler_ {	634	# we create a special coro because we want to cede,
471	while () {	635	# to reduce pressure on the coro pool (because most callbacks
472	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	636	# return immediately and can be reused) and because we cannot cede
473	$cb->(@arg);	637	# inside an event callback.
474
475	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
476	push @unblock_pool, $Coro::current;
477	schedule;
478	}
479	}
480
481	our $unblock_scheduler = async {	638	our $unblock_scheduler = new Coro sub {
482	while () {	639	while () {
483	while (my $cb = pop @unblock_queue) {	640	while (my $cb = pop @unblock_queue) {
484	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	641	# this is an inlined copy of async_pool
485	$handler->{arg} = $cb;	642	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		643
		644	$coro->{_invoke} = $cb;
486	$handler->ready;	645	$coro->ready;
487	cede;	646	cede; # for short-lived callbacks, this reduces pressure on the coro pool
488	}	647	}
489		648	schedule; # sleep well
490	schedule;
491	}	649	}
492	};	650	};
		651	$unblock_scheduler->{desc} = "[unblock_sub scheduler]";
493		652
494	sub unblock_sub(&) {	653	sub unblock_sub(&) {
495	my $cb = shift;	654	my $cb = shift;
496		655
497	sub {	656	sub {
498	push @unblock_queue, [$cb, @_];	657	unshift @unblock_queue, [$cb, @_];
499	$unblock_scheduler->ready;	658	$unblock_scheduler->ready;
500	}	659	}
501	}	660	}
502		661
503	=back	662	=back
…		…
506		665
507	1;	666	1;
508		667
509	=head1 BUGS/LIMITATIONS	668	=head1 BUGS/LIMITATIONS
510		669
511	- you must make very sure that no coro is still active on global
512	destruction. very bad things might happen otherwise (usually segfaults).
513
514	- this module is not thread-safe. You should only ever use this module	670	This module is not perl-pseudo-thread-safe. You should only ever use this
515	from the same thread (this requirement might be losened in the future	671	module from the same thread (this requirement might be removed in the
516	to allow per-thread schedulers, but Coro::State does not yet allow	672	future to allow per-thread schedulers, but Coro::State does not yet allow
517	this).	673	this). I recommend disabling thread support and using processes, as this
		674	is much faster and uses less memory.
518		675
519	=head1 SEE ALSO	676	=head1 SEE ALSO
520		677
		678	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		679
		680	Debugging: L<Coro::Debug>.
		681
521	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	682	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
522		683
523	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	684	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
524		685
525	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	686	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
526		687
527	Embedding: L<Coro:MakeMaker>	688	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		689
		690	XS API: L<Coro::MakeMaker>.
		691
		692	Low level Configuration, Coroutine Environment: L<Coro::State>.
528		693
529	=head1 AUTHOR	694	=head1 AUTHOR
530		695
531	Marc Lehmann <schmorp@schmorp.de>	696	Marc Lehmann <schmorp@schmorp.de>
532	http://home.schmorp.de/	697	http://home.schmorp.de/

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing Coro/Coro.pm (file contents): Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs. Revision 1.210 by root, Sat Nov 8 16:46:32 2008 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs.
Revision 1.210 by root, Sat Nov 8 16:46:32 2008 UTC