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

Comparing Coro/Coro.pm (file contents):
Revision 1.61 by pcg, Fri May 14 13:25:08 2004 UTC vs.
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC

…		…
8		8
9	async {	9	async {
10	# some asynchronous thread of execution	10	# some asynchronous thread of execution
11	};	11	};
12		12
13	# alternatively create an async process like this:	13	# alternatively create an async coroutine like this:
14		14
15	sub some_func : Coro {	15	sub some_func : Coro {
16	# some more async code	16	# some more async code
17	}	17	}
18		18
19	cede;	19	cede;
20		20
21	=head1 DESCRIPTION	21	=head1 DESCRIPTION
22		22
23	This module collection manages coroutines. Coroutines are similar to	23	This module collection manages coroutines. Coroutines are similar
24	threads but don't run in parallel.	24	to threads but don't run in parallel at the same time even on SMP
		25	machines. The specific flavor of coroutine use din this module also
		26	guarentees you that it will not switch between coroutines unless
		27	necessary, at easily-identified points in your program, so locking and
		28	parallel access are rarely an issue, making coroutine programming much
		29	safer than threads programming.
25		30
		31	(Perl, however, does not natively support real threads but instead does a
		32	very slow and memory-intensive emulation of processes using threads. This
		33	is a performance win on Windows machines, and a loss everywhere else).
		34
26	In this module, coroutines are defined as "callchain + lexical variables	35	In this module, coroutines are defined as "callchain + lexical variables +
27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own	36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
28	callchain, it's own set of lexicals and it's own set of perl's most	37	its own set of lexicals and its own set of perls most important global
29	important global variables.	38	variables.
30		39
31	=cut	40	=cut
32		41
33	package Coro;	42	package Coro;
34		43
35	BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") }	44	use strict;
		45	no warnings "uninitialized";
36		46
37	use Coro::State;	47	use Coro::State;
38		48
39	use vars qw($idle $main $current);	49	use base qw(Coro::State Exporter);
40		50
41	use base Exporter;	51	our $idle; # idle handler
		52	our $main; # main coroutine
		53	our $current; # current coroutine
42		54
43	$VERSION = 0.97;	55	our $VERSION = '3.3';
44		56
45	@EXPORT = qw(async cede schedule terminate current);	57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
46	%EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48	);	60	);
49	@EXPORT_OK = @{$EXPORT_TAGS{prio}};	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
50		62
51	{	63	{
52	my @async;	64	my @async;
53	my $init;	65	my $init;
54		66
55	# this way of handling attributes simply is NOT scalable ;()	67	# this way of handling attributes simply is NOT scalable ;()
56	sub import {	68	sub import {
		69	no strict 'refs';
		70
57	Coro->export_to_level(1, @_);	71	Coro->export_to_level (1, @_);
		72
58	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
59	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
60	my ($package, $ref) = (shift, shift);	75	my ($package, $ref) = (shift, shift);
61	my @attrs;	76	my @attrs;
62	for (@_) {	77	for (@_) {
…		…
89		104
90	$main = new Coro;	105	$main = new Coro;
91		106
92	=item $current (or as function: current)	107	=item $current (or as function: current)
93		108
94	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	109	The current coroutine (the last coroutine switched to). The initial value
		110	is C<$main> (of course).
		111
		112	This variable is B<strictly> I<read-only>. It is provided for performance
		113	reasons. If performance is not essentiel you are encouraged to use the
		114	C<Coro::current> function instead.
95		115
96	=cut	116	=cut
97		117
98	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
99	if ($current) {
100	$main->{specific} = $current->{specific};	119	$main->{specific} = $current->{specific}
101	}	120	if $current;
102		121
103	$current = $main;	122	_set_current $main;
104		123
105	sub current() { $current }	124	sub current() { $current }
106		125
107	=item $idle	126	=item $idle
108		127
109	The coroutine to switch to when no other coroutine is running. The default	128	A callback that is called whenever the scheduler finds no ready coroutines
110	implementation prints "FATAL: deadlock detected" and exits.	129	to run. The default implementation prints "FATAL: deadlock detected" and
		130	exits, because the program has no other way to continue.
111		131
112	=cut	132	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
		134	coroutine so the scheduler can run it.
113		135
114	# should be done using priorities :(	136	Please note that if your callback recursively invokes perl (e.g. for event
115	$idle = new Coro sub {	137	handlers), then it must be prepared to be called recursively.
116	print STDERR "FATAL: deadlock detected\n";	138
117	exit(51);	139	=cut
		140
		141	$idle = sub {
		142	require Carp;
		143	Carp::croak ("FATAL: deadlock detected");
118	};	144	};
119		145
120	# this coroutine is necessary because a coroutine	146	# this coroutine is necessary because a coroutine
121	# cannot destroy itself.	147	# cannot destroy itself.
122	my @destroy;	148	my @destroy;
123	my $manager;
124	$manager = new Coro sub {	149	my $manager; $manager = new Coro sub {
125	while () {	150	while () {
126	# by overwriting the state object with the manager we destroy it	151	# by overwriting the state object with the manager we destroy it
127	# while still being able to schedule this coroutine (in case it has	152	# while still being able to schedule this coroutine (in case it has
128	# been readied multiple times. this is harmless since the manager	153	# been readied multiple times. this is harmless since the manager
129	# can be called as many times as neccessary and will always	154	# can be called as many times as neccessary and will always
130	# remove itself from the runqueue	155	# remove itself from the runqueue
131	while (@destroy) {	156	while (@destroy) {
132	my $coro = pop @destroy;	157	my $coro = pop @destroy;
		158
133	$coro->{status} \|\|= [];	159	$coro->{status} \|\|= [];
		160
134	$_->ready for @{delete $coro->{join} \|\| []};	161	$_->ready for @{(delete $coro->{join} ) \|\| []};
		162	$_->(@{$coro->{status}}) for @{(delete $coro->{destroy_cb}) \|\| []};
135		163
136	# the next line destroys the _coro_state, but keeps the	164	# the next line destroys the coro state, but keeps the
137	# process itself intact (we basically make it a zombie	165	# coroutine itself intact (we basically make it a zombie
138	# process that always runs the manager thread, so it's possible	166	# coroutine that always runs the manager thread, so it's possible
139	# to transfer() to this process).	167	# to transfer() to this coroutine).
140	$coro->{_coro_state} = $manager->{_coro_state};	168	$coro->_clone_state_from ($manager);
141	}	169	}
142	&schedule;	170	&schedule;
143	}	171	}
144	};	172	};
145		173
…		…
147		175
148	=back	176	=back
149		177
150	=head2 STATIC METHODS	178	=head2 STATIC METHODS
151		179
152	Static methods are actually functions that operate on the current process only.	180	Static methods are actually functions that operate on the current coroutine only.
153		181
154	=over 4	182	=over 4
155		183
156	=item async { ... } [@args...]	184	=item async { ... } [@args...]
157		185
158	Create a new asynchronous process and return it's process object	186	Create a new asynchronous coroutine and return it's coroutine object
159	(usually unused). When the sub returns the new process is automatically	187	(usually unused). When the sub returns the new coroutine is automatically
160	terminated.	188	terminated.
		189
		190	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		191
		192	When the coroutine dies, the program will exit, just as in the main
		193	program.
161		194
162	# create a new coroutine that just prints its arguments	195	# create a new coroutine that just prints its arguments
163	async {	196	async {
164	print "@_\n";	197	print "@_\n";
165	} 1,2,3,4;	198	} 1,2,3,4;
166		199
167	=cut	200	=cut
168		201
169	sub async(&@) {	202	sub async(&@) {
170	my $pid = new Coro @_;	203	my $pid = new Coro @_;
171	$manager->ready; # this ensures that the stack is cloned from the manager
172	$pid->ready;	204	$pid->ready;
173	$pid;	205	$pid
174	}	206	}
175		207
176	=item schedule	208	=item schedule
177		209
178	Calls the scheduler. Please note that the current process will not be put	210	Calls the scheduler. Please note that the current coroutine will not be put
179	into the ready queue, so calling this function usually means you will	211	into the ready queue, so calling this function usually means you will
180	never be called again.	212	never be called again unless something else (e.g. an event handler) calls
		213	ready.
181		214
182	=cut	215	The canonical way to wait on external events is this:
		216
		217	{
		218	# remember current coroutine
		219	my $current = $Coro::current;
		220
		221	# register a hypothetical event handler
		222	on_event_invoke sub {
		223	# wake up sleeping coroutine
		224	$current->ready;
		225	undef $current;
		226	};
		227
		228	# call schedule until event occured.
		229	# in case we are woken up for other reasons
		230	# (current still defined), loop.
		231	Coro::schedule while $current;
		232	}
183		233
184	=item cede	234	=item cede
185		235
186	"Cede" to other processes. This function puts the current process into the	236	"Cede" to other coroutines. This function puts the current coroutine into the
187	ready queue and calls C<schedule>, which has the effect of giving up the	237	ready queue and calls C<schedule>, which has the effect of giving up the
188	current "timeslice" to other coroutines of the same or higher priority.	238	current "timeslice" to other coroutines of the same or higher priority.
189		239
190	=cut
191
192	=item terminate [arg...]	240	=item terminate [arg...]
193		241
194	Terminates the current process with the given status values (see L<cancel>).	242	Terminates the current coroutine with the given status values (see L<cancel>).
195		243
196	=cut	244	=cut
197		245
198	sub terminate {	246	sub terminate {
199	$current->cancel (@_);	247	$current->cancel (@_);
…		…
201		249
202	=back	250	=back
203		251
204	# dynamic methods	252	# dynamic methods
205		253
206	=head2 PROCESS METHODS	254	=head2 COROUTINE METHODS
207		255
208	These are the methods you can call on process objects.	256	These are the methods you can call on coroutine objects.
209		257
210	=over 4	258	=over 4
211		259
212	=item new Coro \&sub [, @args...]	260	=item new Coro \&sub [, @args...]
213		261
214	Create a new process and return it. When the sub returns the process	262	Create a new coroutine and return it. When the sub returns the coroutine
215	automatically terminates as if C<terminate> with the returned values were	263	automatically terminates as if C<terminate> with the returned values were
216	called. To make the process run you must first put it into the ready queue	264	called. To make the coroutine run you must first put it into the ready queue
217	by calling the ready method.	265	by calling the ready method.
218		266
219	=cut	267	Calling C<exit> in a coroutine will not work correctly, so do not do that.
220		268
		269	=cut
		270
221	sub _newcoro {	271	sub _run_coro {
222	terminate &{+shift};	272	terminate &{+shift};
223	}	273	}
224		274
225	sub new {	275	sub new {
226	my $class = shift;	276	my $class = shift;
227	bless {
228	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
229	}, $class;
230	}
231		277
232	=item $process->ready	278	$class->SUPER::new (\&_run_coro, @_)
		279	}
233		280
234	Put the given process into the ready queue.	281	=item $success = $coroutine->ready
235		282
236	=cut	283	Put the given coroutine into the ready queue (according to it's priority)
		284	and return true. If the coroutine is already in the ready queue, do nothing
		285	and return false.
237		286
		287	=item $is_ready = $coroutine->is_ready
		288
		289	Return wether the coroutine is currently the ready queue or not,
		290
238	=item $process->cancel (arg...)	291	=item $coroutine->cancel (arg...)
239		292
240	Temrinates the given process and makes it return the given arguments as	293	Terminates the given coroutine and makes it return the given arguments as
241	status (default: the empty list).	294	status (default: the empty list).
242		295
243	=cut	296	=cut
244		297
245	sub cancel {	298	sub cancel {
…		…
248	push @destroy, $self;	301	push @destroy, $self;
249	$manager->ready;	302	$manager->ready;
250	&schedule if $current == $self;	303	&schedule if $current == $self;
251	}	304	}
252		305
253	=item $process->join	306	=item $coroutine->join
254		307
255	Wait until the coroutine terminates and return any values given to the	308	Wait until the coroutine terminates and return any values given to the
256	C<terminate> or C<cancel> functions. C<join> can be called multiple times	309	C<terminate> or C<cancel> functions. C<join> can be called multiple times
257	from multiple processes.	310	from multiple coroutine.
258		311
259	=cut	312	=cut
260		313
261	sub join {	314	sub join {
262	my $self = shift;	315	my $self = shift;
…		…
265	&schedule;	318	&schedule;
266	}	319	}
267	wantarray ? @{$self->{status}} : $self->{status}[0];	320	wantarray ? @{$self->{status}} : $self->{status}[0];
268	}	321	}
269		322
		323	=item $coroutine->on_destroy (\&cb)
		324
		325	Registers a callback that is called when this coroutine gets destroyed,
		326	but before it is joined. The callback gets passed the terminate arguments,
		327	if any.
		328
		329	=cut
		330
		331	sub on_destroy {
		332	my ($self, $cb) = @_;
		333
		334	push @{ $self->{destroy_cb} }, $cb;
		335	}
		336
270	=item $oldprio = $process->prio($newprio)	337	=item $oldprio = $coroutine->prio ($newprio)
271		338
272	Sets (or gets, if the argument is missing) the priority of the	339	Sets (or gets, if the argument is missing) the priority of the
273	process. Higher priority processes get run before lower priority	340	coroutine. Higher priority coroutines get run before lower priority
274	processes. Priorities are small signed integers (currently -4 .. +3),	341	coroutines. Priorities are small signed integers (currently -4 .. +3),
275	that you can refer to using PRIO_xxx constants (use the import tag :prio	342	that you can refer to using PRIO_xxx constants (use the import tag :prio
276	to get then):	343	to get then):
277		344
278	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	345	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
279	3 > 1 > 0 > -1 > -3 > -4	346	3 > 1 > 0 > -1 > -3 > -4
…		…
282	current->prio(PRIO_HIGH);	349	current->prio(PRIO_HIGH);
283		350
284	The idle coroutine ($Coro::idle) always has a lower priority than any	351	The idle coroutine ($Coro::idle) always has a lower priority than any
285	existing coroutine.	352	existing coroutine.
286		353
287	Changing the priority of the current process will take effect immediately,	354	Changing the priority of the current coroutine will take effect immediately,
288	but changing the priority of processes in the ready queue (but not	355	but changing the priority of coroutines in the ready queue (but not
289	running) will only take effect after the next schedule (of that	356	running) will only take effect after the next schedule (of that
290	process). This is a bug that will be fixed in some future version.	357	coroutine). This is a bug that will be fixed in some future version.
291		358
292	=cut
293
294	sub prio {
295	my $old = $_[0]{prio};
296	$_[0]{prio} = $_[1] if @_ > 1;
297	$old;
298	}
299
300	=item $newprio = $process->nice($change)	359	=item $newprio = $coroutine->nice ($change)
301		360
302	Similar to C<prio>, but subtract the given value from the priority (i.e.	361	Similar to C<prio>, but subtract the given value from the priority (i.e.
303	higher values mean lower priority, just as in unix).	362	higher values mean lower priority, just as in unix).
304		363
305	=cut
306
307	sub nice {
308	$_[0]{prio} -= $_[1];
309	}
310
311	=item $olddesc = $process->desc($newdesc)	364	=item $olddesc = $coroutine->desc ($newdesc)
312		365
313	Sets (or gets in case the argument is missing) the description for this	366	Sets (or gets in case the argument is missing) the description for this
314	process. This is just a free-form string you can associate with a process.	367	coroutine. This is just a free-form string you can associate with a coroutine.
315		368
316	=cut	369	=cut
317		370
318	sub desc {	371	sub desc {
319	my $old = $_[0]{desc};	372	my $old = $_[0]{desc};
…		…
321	$old;	374	$old;
322	}	375	}
323		376
324	=back	377	=back
325		378
		379	=head2 GLOBAL FUNCTIONS
		380
		381	=over 4
		382
		383	=item Coro::nready
		384
		385	Returns the number of coroutines that are currently in the ready state,
		386	i.e. that can be swicthed to. The value C<0> means that the only runnable
		387	coroutine is the currently running one, so C<cede> would have no effect,
		388	and C<schedule> would cause a deadlock unless there is an idle handler
		389	that wakes up some coroutines.
		390
		391	=item unblock_sub { ... }
		392
		393	This utility function takes a BLOCK or code reference and "unblocks" it,
		394	returning the new coderef. This means that the new coderef will return
		395	immediately without blocking, returning nothing, while the original code
		396	ref will be called (with parameters) from within its own coroutine.
		397
		398	The reason this fucntion exists is that many event libraries (such as the
		399	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		400	of thread-safety). This means you must not block within event callbacks,
		401	otherwise you might suffer from crashes or worse.
		402
		403	This function allows your callbacks to block by executing them in another
		404	coroutine where it is safe to block. One example where blocking is handy
		405	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		406	disk.
		407
		408	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		409	creating event callbacks that want to block.
		410
		411	=cut
		412
		413	our @unblock_pool;
		414	our @unblock_queue;
		415	our $UNBLOCK_POOL_SIZE = 2;
		416
		417	sub unblock_handler_ {
		418	while () {
		419	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		420	$cb->(@arg);
		421
		422	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		423	push @unblock_pool, $Coro::current;
		424	schedule;
		425	}
		426	}
		427
		428	our $unblock_scheduler = async {
		429	while () {
		430	while (my $cb = pop @unblock_queue) {
		431	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		432	$handler->{arg} = $cb;
		433	$handler->ready;
		434	cede;
		435	}
		436
		437	schedule;
		438	}
		439	};
		440
		441	sub unblock_sub(&) {
		442	my $cb = shift;
		443
		444	sub {
		445	push @unblock_queue, [$cb, @_];
		446	$unblock_scheduler->ready;
		447	}
		448	}
		449
		450	=back
		451
326	=cut	452	=cut
327		453
328	1;	454	1;
329		455
330	=head1 BUGS/LIMITATIONS	456	=head1 BUGS/LIMITATIONS
…		…
337	to allow per-thread schedulers, but Coro::State does not yet allow	463	to allow per-thread schedulers, but Coro::State does not yet allow
338	this).	464	this).
339		465
340	=head1 SEE ALSO	466	=head1 SEE ALSO
341		467
342	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	468	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
343	L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,	469
344	L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>.	470	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		471
		472	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		473
		474	Embedding: L<Coro:MakeMaker>
345		475
346	=head1 AUTHOR	476	=head1 AUTHOR
347		477
348	Marc Lehmann <pcg@goof.com>	478	Marc Lehmann <schmorp@schmorp.de>
349	http://www.goof.com/pcg/marc/	479	http://home.schmorp.de/
350		480
351	=cut	481	=cut
352		482

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Comparing Coro/Coro.pm (file contents): Revision 1.61 by pcg, Fri May 14 13:25:08 2004 UTC vs. Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.61 by pcg, Fri May 14 13:25:08 2004 UTC vs.
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC