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

Comparing Coro/Coro.pm (file contents):
Revision 1.41 by root, Tue Nov 6 20:34:09 2001 UTC vs.
Revision 1.94 by root, Sat Dec 2 18:01:30 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 to
24	Threads but don't run in parallel.	24	threads but don't run in parallel.
25
26	This module is still experimental, see the BUGS section below.
27		25
28	In this module, coroutines are defined as "callchain + lexical variables	26	In this module, coroutines are defined as "callchain + lexical variables
29	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own	27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30	callchain, it's own set of lexicals and it's own set of perl's most	28	callchain, it's own set of lexicals and it's own set of perl's most
31	important global variables.	29	important global variables.
32		30
33	=cut	31	=cut
34		32
35	package Coro;	33	package Coro;
36		34
		35	use strict;
37	no warnings qw(uninitialized);	36	no warnings "uninitialized";
38		37
39	use Coro::State;	38	use Coro::State;
40		39
41	use base Exporter;	40	use base qw(Coro::State Exporter);
42		41
43	$VERSION = 0.52;	42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
44		45
		46	our $VERSION = '3.0';
		47
45	@EXPORT = qw(async cede schedule terminate current);	48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
46	%EXPORT_TAGS = (	49	our %EXPORT_TAGS = (
47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48	);	51	);
49	@EXPORT_OK = @{$EXPORT_TAGS{prio}};	52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
50		53
51	{	54	{
52	my @async;	55	my @async;
53	my $init;	56	my $init;
54		57
55	# this way of handling attributes simply is NOT scalable ;()	58	# this way of handling attributes simply is NOT scalable ;()
56	sub import {	59	sub import {
		60	no strict 'refs';
		61
57	Coro->export_to_level(1, @_);	62	Coro->export_to_level (1, @_);
		63
58	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
59	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
60	my ($package, $ref) = (shift, shift);	66	my ($package, $ref) = (shift, shift);
61	my @attrs;	67	my @attrs;
62	for (@_) {	68	for (@_) {
…		…
77	};	83	};
78	}	84	}
79		85
80	}	86	}
81		87
		88	=over 4
		89
82	=item $main	90	=item $main
83		91
84	This coroutine represents the main program.	92	This coroutine represents the main program.
85		93
86	=cut	94	=cut
87		95
88	our $main = new Coro;	96	$main = new Coro;
89		97
90	=item $current (or as function: current)	98	=item $current (or as function: current)
91		99
92	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$main> (of course).
		102
		103	This variable is B<strictly> I<read-only>. It is provided for performance
		104	reasons. If performance is not essentiel you are encouraged to use the
		105	C<Coro::current> function instead.
93		106
94	=cut	107	=cut
95		108
96	# maybe some other module used Coro::Specific before...	109	# maybe some other module used Coro::Specific before...
97	if ($current) {
98	$main->{specific} = $current->{specific};	110	$main->{specific} = $current->{specific}
99	}	111	if $current;
100		112
101	our $current = $main;	113	_set_current $main;
102		114
103	sub current() { $current }	115	sub current() { $current }
104		116
105	=item $idle	117	=item $idle
106		118
107	The coroutine to switch to when no other coroutine is running. The default	119	A callback that is called whenever the scheduler finds no ready coroutines
108	implementation prints "FATAL: deadlock detected" and exits.	120	to run. The default implementation prints "FATAL: deadlock detected" and
		121	exits, because the program has no other way to continue.
109		122
110	=cut	123	This hook is overwritten by modules such as C<Coro::Timer> and
		124	C<Coro::Event> to wait on an external event that hopefully wake up a
		125	coroutine so the scheduler can run it.
111		126
112	# should be done using priorities :(	127	Please note that if your callback recursively invokes perl (e.g. for event
113	our $idle = new Coro sub {	128	handlers), then it must be prepared to be called recursively.
		129
		130	=cut
		131
		132	$idle = sub {
114	print STDERR "FATAL: deadlock detected\n";	133	print STDERR "FATAL: deadlock detected\n";
115	exit(51);	134	exit (51);
116	};	135	};
117		136
118	# this coroutine is necessary because a coroutine	137	# this coroutine is necessary because a coroutine
119	# cannot destroy itself.	138	# cannot destroy itself.
120	my @destroy;	139	my @destroy;
121	my $manager;
122	$manager = new Coro sub {	140	my $manager; $manager = new Coro sub {
123	while() {	141	while () {
124	# by overwriting the state object with the manager we destroy it	142	# by overwriting the state object with the manager we destroy it
125	# while still being able to schedule this coroutine (in case it has	143	# while still being able to schedule this coroutine (in case it has
126	# been readied multiple times. this is harmless since the manager	144	# been readied multiple times. this is harmless since the manager
127	# can be called as many times as neccessary and will always	145	# can be called as many times as neccessary and will always
128	# remove itself from the runqueue	146	# remove itself from the runqueue
129	while (@destroy) {	147	while (@destroy) {
130	my $coro = pop @destroy;	148	my $coro = pop @destroy;
131	$coro->{status} \|\|= [];	149	$coro->{status} \|\|= [];
132	$_->ready for @{delete $coro->{join} \|\| []};	150	$_->ready for @{delete $coro->{join} \|\| []};
133	$coro->{_coro_state} = $manager->{_coro_state};	151
		152	# the next line destroys the coro state, but keeps the
		153	# coroutine itself intact (we basically make it a zombie
		154	# coroutine that always runs the manager thread, so it's possible
		155	# to transfer() to this coroutine).
		156	$coro->_clone_state_from ($manager);
134	}	157	}
135	&schedule;	158	&schedule;
136	}	159	}
137	};	160	};
138		161
139	# static methods. not really.	162	# static methods. not really.
140		163
		164	=back
		165
141	=head2 STATIC METHODS	166	=head2 STATIC METHODS
142		167
143	Static methods are actually functions that operate on the current process only.	168	Static methods are actually functions that operate on the current coroutine only.
144		169
145	=over 4	170	=over 4
146		171
147	=item async { ... } [@args...]	172	=item async { ... } [@args...]
148		173
149	Create a new asynchronous process and return it's process object	174	Create a new asynchronous coroutine and return it's coroutine object
150	(usually unused). When the sub returns the new process is automatically	175	(usually unused). When the sub returns the new coroutine is automatically
151	terminated.	176	terminated.
		177
		178	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		179
		180	When the coroutine dies, the program will exit, just as in the main
		181	program.
152		182
153	# create a new coroutine that just prints its arguments	183	# create a new coroutine that just prints its arguments
154	async {	184	async {
155	print "@_\n";	185	print "@_\n";
156	} 1,2,3,4;	186	} 1,2,3,4;
157		187
158	The coderef you submit MUST NOT be a closure that refers to variables
159	in an outer scope. This does NOT work. Pass arguments into it instead.
160
161	=cut	188	=cut
162		189
163	sub async(&@) {	190	sub async(&@) {
164	my $pid = new Coro @_;	191	my $pid = new Coro @_;
165	$manager->ready; # this ensures that the stack is cloned from the manager
166	$pid->ready;	192	$pid->ready;
167	$pid;	193	$pid
168	}	194	}
169		195
170	=item schedule	196	=item schedule
171		197
172	Calls the scheduler. Please note that the current process will not be put	198	Calls the scheduler. Please note that the current coroutine will not be put
173	into the ready queue, so calling this function usually means you will	199	into the ready queue, so calling this function usually means you will
174	never be called again.	200	never be called again unless something else (e.g. an event handler) calls
		201	ready.
175		202
176	=cut	203	The canonical way to wait on external events is this:
		204
		205	{
		206	# remember current coroutine
		207	my $current = $Coro::current;
		208
		209	# register a hypothetical event handler
		210	on_event_invoke sub {
		211	# wake up sleeping coroutine
		212	$current->ready;
		213	undef $current;
		214	};
		215
		216	# call schedule until event occured.
		217	# in case we are woken up for other reasons
		218	# (current still defined), loop.
		219	Coro::schedule while $current;
		220	}
177		221
178	=item cede	222	=item cede
179		223
180	"Cede" to other processes. This function puts the current process into the	224	"Cede" to other coroutines. This function puts the current coroutine into the
181	ready queue and calls C<schedule>, which has the effect of giving up the	225	ready queue and calls C<schedule>, which has the effect of giving up the
182	current "timeslice" to other coroutines of the same or higher priority.	226	current "timeslice" to other coroutines of the same or higher priority.
183		227
184	=cut
185
186	=item terminate [arg...]	228	=item terminate [arg...]
187		229
188	Terminates the current process.	230	Terminates the current coroutine with the given status values (see L<cancel>).
189
190	Future versions of this function will allow result arguments.
191		231
192	=cut	232	=cut
193		233
194	sub terminate {	234	sub terminate {
195	$current->{status} = [@_];
196	$current->cancel;	235	$current->cancel (@_);
197	&schedule;
198	die; # NORETURN
199	}	236	}
200		237
201	=back	238	=back
202		239
203	# dynamic methods	240	# dynamic methods
204		241
205	=head2 PROCESS METHODS	242	=head2 COROUTINE METHODS
206		243
207	These are the methods you can call on process objects.	244	These are the methods you can call on coroutine objects.
208		245
209	=over 4	246	=over 4
210		247
211	=item new Coro \&sub [, @args...]	248	=item new Coro \&sub [, @args...]
212		249
213	Create a new process and return it. When the sub returns the process	250	Create a new coroutine and return it. When the sub returns the coroutine
214	automatically terminates as if C<terminate> with the returned values were	251	automatically terminates as if C<terminate> with the returned values were
215	called. To make the process run you must first put it into the ready queue	252	called. To make the coroutine run you must first put it into the ready queue
216	by calling the ready method.	253	by calling the ready method.
217		254
218	=cut	255	Calling C<exit> in a coroutine will not work correctly, so do not do that.
219		256
		257	=cut
		258
220	sub _newcoro {	259	sub _run_coro {
221	terminate &{+shift};	260	terminate &{+shift};
222	}	261	}
223		262
224	sub new {	263	sub new {
225	my $class = shift;	264	my $class = shift;
226	bless {
227	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
228	}, $class;
229	}
230		265
231	=item $process->ready	266	$class->SUPER::new (\&_run_coro, @_)
		267	}
232		268
233	Put the given process into the ready queue.	269	=item $success = $coroutine->ready
234		270
235	=cut	271	Put the given coroutine into the ready queue (according to it's priority)
		272	and return true. If the coroutine is already in the ready queue, do nothing
		273	and return false.
236		274
237	=item $process->cancel	275	=item $is_ready = $coroutine->is_ready
238		276
239	Like C<terminate>, but terminates the specified process instead.	277	Return wether the coroutine is currently the ready queue or not,
		278
		279	=item $coroutine->cancel (arg...)
		280
		281	Terminates the given coroutine and makes it return the given arguments as
		282	status (default: the empty list).
240		283
241	=cut	284	=cut
242		285
243	sub cancel {	286	sub cancel {
		287	my $self = shift;
		288	$self->{status} = [@_];
244	push @destroy, $_[0];	289	push @destroy, $self;
245	$manager->ready;	290	$manager->ready;
246	&schedule if $current == $_[0];	291	&schedule if $current == $self;
247	}	292	}
248		293
249	=item $process->join	294	=item $coroutine->join
250		295
251	Wait until the coroutine terminates and return any values given to the	296	Wait until the coroutine terminates and return any values given to the
252	C<terminate> function. C<join> can be called multiple times from multiple	297	C<terminate> or C<cancel> functions. C<join> can be called multiple times
253	processes.	298	from multiple coroutine.
254		299
255	=cut	300	=cut
256		301
257	sub join {	302	sub join {
258	my $self = shift;	303	my $self = shift;
…		…
261	&schedule;	306	&schedule;
262	}	307	}
263	wantarray ? @{$self->{status}} : $self->{status}[0];	308	wantarray ? @{$self->{status}} : $self->{status}[0];
264	}	309	}
265		310
266	=item $oldprio = $process->prio($newprio)	311	=item $oldprio = $coroutine->prio ($newprio)
267		312
268	Sets (or gets, if the argument is missing) the priority of the	313	Sets (or gets, if the argument is missing) the priority of the
269	process. Higher priority processes get run before lower priority	314	coroutine. Higher priority coroutines get run before lower priority
270	processes. Priorities are smalled signed integer (currently -4 .. +3),	315	coroutines. Priorities are small signed integers (currently -4 .. +3),
271	that you can refer to using PRIO_xxx constants (use the import tag :prio	316	that you can refer to using PRIO_xxx constants (use the import tag :prio
272	to get then):	317	to get then):
273		318
274	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	319	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
275	3 > 1 > 0 > -1 > -3 > -4	320	3 > 1 > 0 > -1 > -3 > -4
…		…
278	current->prio(PRIO_HIGH);	323	current->prio(PRIO_HIGH);
279		324
280	The idle coroutine ($Coro::idle) always has a lower priority than any	325	The idle coroutine ($Coro::idle) always has a lower priority than any
281	existing coroutine.	326	existing coroutine.
282		327
283	Changing the priority of the current process will take effect immediately,	328	Changing the priority of the current coroutine will take effect immediately,
284	but changing the priority of processes in the ready queue (but not	329	but changing the priority of coroutines in the ready queue (but not
285	running) will only take effect after the next schedule (of that	330	running) will only take effect after the next schedule (of that
286	process). This is a bug that will be fixed in some future version.	331	coroutine). This is a bug that will be fixed in some future version.
287		332
288	=cut
289
290	sub prio {
291	my $old = $_[0]{prio};
292	$_[0]{prio} = $_[1] if @_ > 1;
293	$old;
294	}
295
296	=item $newprio = $process->nice($change)	333	=item $newprio = $coroutine->nice ($change)
297		334
298	Similar to C<prio>, but subtract the given value from the priority (i.e.	335	Similar to C<prio>, but subtract the given value from the priority (i.e.
299	higher values mean lower priority, just as in unix).	336	higher values mean lower priority, just as in unix).
300		337
301	=cut
302
303	sub nice {
304	$_[0]{prio} -= $_[1];
305	}
306
307	=item $olddesc = $process->desc($newdesc)	338	=item $olddesc = $coroutine->desc ($newdesc)
308		339
309	Sets (or gets in case the argument is missing) the description for this	340	Sets (or gets in case the argument is missing) the description for this
310	process. This is just a free-form string you can associate with a process.	341	coroutine. This is just a free-form string you can associate with a coroutine.
311		342
312	=cut	343	=cut
313		344
314	sub desc {	345	sub desc {
315	my $old = $_[0]{desc};	346	my $old = $_[0]{desc};
…		…
317	$old;	348	$old;
318	}	349	}
319		350
320	=back	351	=back
321		352
		353	=head2 UTILITY FUNCTIONS
		354
		355	=over 4
		356
		357	=item unblock_sub { ... }
		358
		359	This utility function takes a BLOCK or code reference and "unblocks" it,
		360	returning the new coderef. This means that the new coderef will return
		361	immediately without blocking, returning nothing, while the original code
		362	ref will be called (with parameters) from within its own coroutine.
		363
		364	The reason this fucntion exists is that many event libraries (such as the
		365	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		366	of thread-safety). This means you must not block within event callbacks,
		367	otherwise you might suffer from crashes or worse.
		368
		369	This function allows your callbacks to block by executing them in another
		370	coroutine where it is safe to block. One example where blocking is handy
		371	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		372	disk.
		373
		374	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		375	creating event callbacks that want to block.
		376
		377	=cut
		378
		379	our @unblock_pool;
		380	our @unblock_queue;
		381	our $UNBLOCK_POOL_SIZE = 2;
		382
		383	sub unblock_handler_ {
		384	while () {
		385	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		386	$cb->(@arg);
		387
		388	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		389	push @unblock_pool, $Coro::current;
		390	schedule;
		391	}
		392	}
		393
		394	our $unblock_scheduler = async {
		395	while () {
		396	while (my $cb = pop @unblock_queue) {
		397	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		398	$handler->{arg} = $cb;
		399	$handler->ready;
		400	cede;
		401	}
		402
		403	schedule;
		404	}
		405	};
		406
		407	sub unblock_sub(&) {
		408	my $cb = shift;
		409
		410	sub {
		411	push @unblock_queue, [$cb, @_];
		412	$unblock_scheduler->ready;
		413	}
		414	}
		415
		416	=back
		417
322	=cut	418	=cut
323		419
324	1;	420	1;
325		421
326	=head1 BUGS/LIMITATIONS	422	=head1 BUGS/LIMITATIONS
327		423
328	- you must make very sure that no coro is still active on global destruction.	424	- you must make very sure that no coro is still active on global
329	very bad things might happen otherwise (usually segfaults).	425	destruction. very bad things might happen otherwise (usually segfaults).
		426
330	- this module is not thread-safe. You must only ever use this module from	427	- this module is not thread-safe. You should only ever use this module
331	the same thread (this requirement might be loosened in the future to	428	from the same thread (this requirement might be losened in the future
332	allow per-thread schedulers, but Coro::State does not yet allow this).	429	to allow per-thread schedulers, but Coro::State does not yet allow
		430	this).
333		431
334	=head1 SEE ALSO	432	=head1 SEE ALSO
335		433
336	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	434	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
337	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,	435
338	L<Coro::Handle>, L<Coro::Socket>.	436	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		437
		438	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		439
		440	Embedding: L<Coro:MakeMaker>
339		441
340	=head1 AUTHOR	442	=head1 AUTHOR
341		443
342	Marc Lehmann <pcg@goof.com>	444	Marc Lehmann <schmorp@schmorp.de>
343	http://www.goof.com/pcg/marc/	445	http://home.schmorp.de/
344		446
345	=cut	447	=cut
346		448

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Comparing Coro/Coro.pm (file contents): Revision 1.41 by root, Tue Nov 6 20:34:09 2001 UTC vs. Revision 1.94 by root, Sat Dec 2 18:01:30 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.41 by root, Tue Nov 6 20:34:09 2001 UTC vs.
Revision 1.94 by root, Sat Dec 2 18:01:30 2006 UTC