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

Comparing Coro/Coro.pm (file contents):
Revision 1.72 by root, Mon Dec 12 17:49:07 2005 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	use strict;	44	use strict;
36	no warnings "uninitialized";	45	no warnings "uninitialized";
37		46
38	use Coro::State;	47	use Coro::State;
39		48
40	use base Exporter::;	49	use base qw(Coro::State Exporter);
41		50
42	our $idle; # idle coroutine	51	our $idle; # idle handler
43	our $main; # main coroutine	52	our $main; # main coroutine
44	our $current; # current coroutine	53	our $current; # current coroutine
45		54
46	our $VERSION = 1.51;	55	our $VERSION = '3.3';
47		56
48	our @EXPORT = qw(async cede schedule terminate current);	57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
49	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51	);	60	);
52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
53		62
54	{	63	{
55	my @async;	64	my @async;
56	my $init;	65	my $init;
57		66
58	# this way of handling attributes simply is NOT scalable ;()	67	# this way of handling attributes simply is NOT scalable ;()
59	sub import {	68	sub import {
60	no strict 'refs';	69	no strict 'refs';
61		70
62	Coro->export_to_level(1, @_);	71	Coro->export_to_level (1, @_);
63		72
64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
66	my ($package, $ref) = (shift, shift);	75	my ($package, $ref) = (shift, shift);
67	my @attrs;	76	my @attrs;
…		…
95		104
96	$main = new Coro;	105	$main = new Coro;
97		106
98	=item $current (or as function: current)	107	=item $current (or as function: current)
99		108
100	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	109	The current coroutine (the last coroutine switched to). The initial value
		110	is C<$main> (of course).
		111
		112	This variable is B<strictly> I<read-only>. It is provided for performance
		113	reasons. If performance is not essentiel you are encouraged to use the
		114	C<Coro::current> function instead.
101		115
102	=cut	116	=cut
103		117
104	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
105	if ($current) {
106	$main->{specific} = $current->{specific};	119	$main->{specific} = $current->{specific}
107	}	120	if $current;
108		121
109	$current = $main;	122	_set_current $main;
110		123
111	sub current() { $current }	124	sub current() { $current }
112		125
113	=item $idle	126	=item $idle
114		127
115	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
116	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.
117		131
118	=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.
119		135
120	# should be done using priorities :(	136	Please note that if your callback recursively invokes perl (e.g. for event
121	$idle = new Coro sub {	137	handlers), then it must be prepared to be called recursively.
122	print STDERR "FATAL: deadlock detected\n";	138
123	exit(51);	139	=cut
		140
		141	$idle = sub {
		142	require Carp;
		143	Carp::croak ("FATAL: deadlock detected");
124	};	144	};
125		145
126	# this coroutine is necessary because a coroutine	146	# this coroutine is necessary because a coroutine
127	# cannot destroy itself.	147	# cannot destroy itself.
128	my @destroy;	148	my @destroy;
129	my $manager;
130	$manager = new Coro sub {	149	my $manager; $manager = new Coro sub {
131	while () {	150	while () {
132	# by overwriting the state object with the manager we destroy it	151	# by overwriting the state object with the manager we destroy it
133	# 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
134	# been readied multiple times. this is harmless since the manager	153	# been readied multiple times. this is harmless since the manager
135	# can be called as many times as neccessary and will always	154	# can be called as many times as neccessary and will always
136	# remove itself from the runqueue	155	# remove itself from the runqueue
137	while (@destroy) {	156	while (@destroy) {
138	my $coro = pop @destroy;	157	my $coro = pop @destroy;
		158
139	$coro->{status} \|\|= [];	159	$coro->{status} \|\|= [];
		160
140	$_->ready for @{delete $coro->{join} \|\| []};	161	$_->ready for @{(delete $coro->{join} ) \|\| []};
		162	$_->(@{$coro->{status}}) for @{(delete $coro->{destroy_cb}) \|\| []};
141		163
142	# the next line destroys the _coro_state, but keeps the	164	# the next line destroys the coro state, but keeps the
143	# process itself intact (we basically make it a zombie	165	# coroutine itself intact (we basically make it a zombie
144	# process that always runs the manager thread, so it's possible	166	# coroutine that always runs the manager thread, so it's possible
145	# to transfer() to this process).	167	# to transfer() to this coroutine).
146	$coro->{_coro_state} = $manager->{_coro_state};	168	$coro->_clone_state_from ($manager);
147	}	169	}
148	&schedule;	170	&schedule;
149	}	171	}
150	};	172	};
151		173
…		…
153		175
154	=back	176	=back
155		177
156	=head2 STATIC METHODS	178	=head2 STATIC METHODS
157		179
158	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.
159		181
160	=over 4	182	=over 4
161		183
162	=item async { ... } [@args...]	184	=item async { ... } [@args...]
163		185
164	Create a new asynchronous process and return it's process object	186	Create a new asynchronous coroutine and return it's coroutine object
165	(usually unused). When the sub returns the new process is automatically	187	(usually unused). When the sub returns the new coroutine is automatically
166	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.
167		194
168	# create a new coroutine that just prints its arguments	195	# create a new coroutine that just prints its arguments
169	async {	196	async {
170	print "@_\n";	197	print "@_\n";
171	} 1,2,3,4;	198	} 1,2,3,4;
172		199
173	=cut	200	=cut
174		201
175	sub async(&@) {	202	sub async(&@) {
176	my $pid = new Coro @_;	203	my $pid = new Coro @_;
177	$manager->ready; # this ensures that the stack is cloned from the manager
178	$pid->ready;	204	$pid->ready;
179	$pid;	205	$pid
180	}	206	}
181		207
182	=item schedule	208	=item schedule
183		209
184	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
185	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
186	never be called again.	212	never be called again unless something else (e.g. an event handler) calls
		213	ready.
187		214
188	=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	}
189		233
190	=item cede	234	=item cede
191		235
192	"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
193	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
194	current "timeslice" to other coroutines of the same or higher priority.	238	current "timeslice" to other coroutines of the same or higher priority.
195		239
196	=cut
197
198	=item terminate [arg...]	240	=item terminate [arg...]
199		241
200	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>).
201		243
202	=cut	244	=cut
203		245
204	sub terminate {	246	sub terminate {
205	$current->cancel (@_);	247	$current->cancel (@_);
…		…
207		249
208	=back	250	=back
209		251
210	# dynamic methods	252	# dynamic methods
211		253
212	=head2 PROCESS METHODS	254	=head2 COROUTINE METHODS
213		255
214	These are the methods you can call on process objects.	256	These are the methods you can call on coroutine objects.
215		257
216	=over 4	258	=over 4
217		259
218	=item new Coro \&sub [, @args...]	260	=item new Coro \&sub [, @args...]
219		261
220	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
221	automatically terminates as if C<terminate> with the returned values were	263	automatically terminates as if C<terminate> with the returned values were
222	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
223	by calling the ready method.	265	by calling the ready method.
224		266
225	=cut	267	Calling C<exit> in a coroutine will not work correctly, so do not do that.
226		268
		269	=cut
		270
227	sub _newcoro {	271	sub _run_coro {
228	terminate &{+shift};	272	terminate &{+shift};
229	}	273	}
230		274
231	sub new {	275	sub new {
232	my $class = shift;	276	my $class = shift;
233	bless {
234	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
235	}, $class;
236	}
237		277
238	=item $process->ready	278	$class->SUPER::new (\&_run_coro, @_)
		279	}
239		280
240	Put the given process into the ready queue.	281	=item $success = $coroutine->ready
241		282
242	=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.
243		286
		287	=item $is_ready = $coroutine->is_ready
		288
		289	Return wether the coroutine is currently the ready queue or not,
		290
244	=item $process->cancel (arg...)	291	=item $coroutine->cancel (arg...)
245		292
246	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
247	status (default: the empty list).	294	status (default: the empty list).
248		295
249	=cut	296	=cut
250		297
251	sub cancel {	298	sub cancel {
…		…
254	push @destroy, $self;	301	push @destroy, $self;
255	$manager->ready;	302	$manager->ready;
256	&schedule if $current == $self;	303	&schedule if $current == $self;
257	}	304	}
258		305
259	=item $process->join	306	=item $coroutine->join
260		307
261	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
262	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
263	from multiple processes.	310	from multiple coroutine.
264		311
265	=cut	312	=cut
266		313
267	sub join {	314	sub join {
268	my $self = shift;	315	my $self = shift;
…		…
271	&schedule;	318	&schedule;
272	}	319	}
273	wantarray ? @{$self->{status}} : $self->{status}[0];	320	wantarray ? @{$self->{status}} : $self->{status}[0];
274	}	321	}
275		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
276	=item $oldprio = $process->prio($newprio)	337	=item $oldprio = $coroutine->prio ($newprio)
277		338
278	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
279	process. Higher priority processes get run before lower priority	340	coroutine. Higher priority coroutines get run before lower priority
280	processes. Priorities are small signed integers (currently -4 .. +3),	341	coroutines. Priorities are small signed integers (currently -4 .. +3),
281	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
282	to get then):	343	to get then):
283		344
284	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
285	3 > 1 > 0 > -1 > -3 > -4	346	3 > 1 > 0 > -1 > -3 > -4
…		…
288	current->prio(PRIO_HIGH);	349	current->prio(PRIO_HIGH);
289		350
290	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
291	existing coroutine.	352	existing coroutine.
292		353
293	Changing the priority of the current process will take effect immediately,	354	Changing the priority of the current coroutine will take effect immediately,
294	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
295	running) will only take effect after the next schedule (of that	356	running) will only take effect after the next schedule (of that
296	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.
297		358
298	=cut
299
300	sub prio {
301	my $old = $_[0]{prio};
302	$_[0]{prio} = $_[1] if @_ > 1;
303	$old;
304	}
305
306	=item $newprio = $process->nice($change)	359	=item $newprio = $coroutine->nice ($change)
307		360
308	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.
309	higher values mean lower priority, just as in unix).	362	higher values mean lower priority, just as in unix).
310		363
311	=cut
312
313	sub nice {
314	$_[0]{prio} -= $_[1];
315	}
316
317	=item $olddesc = $process->desc($newdesc)	364	=item $olddesc = $coroutine->desc ($newdesc)
318		365
319	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
320	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.
321		368
322	=cut	369	=cut
323		370
324	sub desc {	371	sub desc {
325	my $old = $_[0]{desc};	372	my $old = $_[0]{desc};
…		…
327	$old;	374	$old;
328	}	375	}
329		376
330	=back	377	=back
331		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
332	=cut	452	=cut
333		453
334	1;	454	1;
335		455
336	=head1 BUGS/LIMITATIONS	456	=head1 BUGS/LIMITATIONS

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Comparing Coro/Coro.pm (file contents): Revision 1.72 by root, Mon Dec 12 17:49:07 2005 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 1.72 by root, Mon Dec 12 17:49:07 2005 UTC vs.
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC