[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 1.102 by root, Fri Dec 29 11:37:49 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
26	This module is still experimental, see the BUGS section below.	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).
27		34
28	In this module, coroutines are defined as "callchain + lexical variables	35	In this module, coroutines are defined as "callchain + lexical variables +
29	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own	36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
30	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
31	important global variables.	38	variables.
32		39
33	=cut	40	=cut
34		41
35	package Coro;	42	package Coro;
36		43
		44	use strict;
37	no warnings qw(uninitialized);	45	no warnings "uninitialized";
38		46
39	use Coro::State;	47	use Coro::State;
40		48
41	use base Exporter;	49	use base qw(Coro::State Exporter);
42		50
43	$VERSION = 0.52;	51	our $idle; # idle handler
		52	our $main; # main coroutine
		53	our $current; # current coroutine
44		54
		55	our $VERSION = '3.3';
		56
45	@EXPORT = qw(async cede schedule terminate current);	57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
46	%EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48	);	60	);
49	@EXPORT_OK = @{$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 (@_) {
…		…
77	};	92	};
78	}	93	}
79		94
80	}	95	}
81		96
		97	=over 4
		98
82	=item $main	99	=item $main
83		100
84	This coroutine represents the main program.	101	This coroutine represents the main program.
85		102
86	=cut	103	=cut
87		104
88	our $main = new Coro;	105	$main = new Coro;
89		106
90	=item $current (or as function: current)	107	=item $current (or as function: current)
91		108
92	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	109	The current coroutine (the last coroutine switched to). The initial value
		110	is C<$main> (of course).
		111
		112	This variable is B<strictly> I<read-only>. It is provided for performance
		113	reasons. If performance is not essentiel you are encouraged to use the
		114	C<Coro::current> function instead.
93		115
94	=cut	116	=cut
95		117
96	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
97	if ($current) {
98	$main->{specific} = $current->{specific};	119	$main->{specific} = $current->{specific}
99	}	120	if $current;
100		121
101	our $current = $main;	122	_set_current $main;
102		123
103	sub current() { $current }	124	sub current() { $current }
104		125
105	=item $idle	126	=item $idle
106		127
107	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
108	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.
109		131
110	=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.
111		135
112	# should be done using priorities :(	136	Please note that if your callback recursively invokes perl (e.g. for event
113	our $idle = new Coro sub {	137	handlers), then it must be prepared to be called recursively.
114	print STDERR "FATAL: deadlock detected\n";	138
115	exit(51);	139	=cut
		140
		141	$idle = sub {
		142	require Carp;
		143	Carp::croak ("FATAL: deadlock detected");
116	};	144	};
117		145
118	# this coroutine is necessary because a coroutine	146	# this coroutine is necessary because a coroutine
119	# cannot destroy itself.	147	# cannot destroy itself.
120	my @destroy;	148	my @destroy;
121	my $manager;
122	$manager = new Coro sub {	149	my $manager; $manager = new Coro sub {
123	while() {	150	while () {
124	# by overwriting the state object with the manager we destroy it	151	# by overwriting the state object with the manager we destroy it
125	# 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
126	# been readied multiple times. this is harmless since the manager	153	# been readied multiple times. this is harmless since the manager
127	# can be called as many times as neccessary and will always	154	# can be called as many times as neccessary and will always
128	# remove itself from the runqueue	155	# remove itself from the runqueue
129	while (@destroy) {	156	while (@destroy) {
130	my $coro = pop @destroy;	157	my $coro = pop @destroy;
		158
131	$coro->{status} \|\|= [];	159	$coro->{status} \|\|= [];
		160
132	$_->ready for @{delete $coro->{join} \|\| []};	161	$_->ready for @{(delete $coro->{join} ) \|\| []};
133	$coro->{_coro_state} = $manager->{_coro_state};	162	$_->(@{$coro->{status}}) for @{(delete $coro->{destroy_cb}) \|\| []};
		163
		164	# the next line destroys the coro state, but keeps the
		165	# coroutine itself intact (we basically make it a zombie
		166	# coroutine that always runs the manager thread, so it's possible
		167	# to transfer() to this coroutine).
		168	$coro->_clone_state_from ($manager);
134	}	169	}
135	&schedule;	170	&schedule;
136	}	171	}
137	};	172	};
138		173
139	# static methods. not really.	174	# static methods. not really.
140		175
		176	=back
		177
141	=head2 STATIC METHODS	178	=head2 STATIC METHODS
142		179
143	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.
144		181
145	=over 4	182	=over 4
146		183
147	=item async { ... } [@args...]	184	=item async { ... } [@args...]
148		185
149	Create a new asynchronous process and return it's process object	186	Create a new asynchronous coroutine and return it's coroutine object
150	(usually unused). When the sub returns the new process is automatically	187	(usually unused). When the sub returns the new coroutine is automatically
151	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.
152		194
153	# create a new coroutine that just prints its arguments	195	# create a new coroutine that just prints its arguments
154	async {	196	async {
155	print "@_\n";	197	print "@_\n";
156	} 1,2,3,4;	198	} 1,2,3,4;
157		199
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	200	=cut
162		201
163	sub async(&@) {	202	sub async(&@) {
164	my $pid = new Coro @_;	203	my $pid = new Coro @_;
165	$manager->ready; # this ensures that the stack is cloned from the manager
166	$pid->ready;	204	$pid->ready;
167	$pid;	205	$pid
168	}	206	}
169		207
170	=item schedule	208	=item schedule
171		209
172	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
173	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
174	never be called again.	212	never be called again unless something else (e.g. an event handler) calls
		213	ready.
175		214
176	=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	}
177		233
178	=item cede	234	=item cede
179		235
180	"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
181	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
182	current "timeslice" to other coroutines of the same or higher priority.	238	current "timeslice" to other coroutines of the same or higher priority.
183		239
184	=cut	240	=item Coro::cede_notself
		241
		242	Works like cede, but is not exported by default and will cede to any
		243	coroutine, regardless of priority, once.
185		244
186	=item terminate [arg...]	245	=item terminate [arg...]
187		246
188	Terminates the current process.	247	Terminates the current coroutine with the given status values (see L<cancel>).
189
190	Future versions of this function will allow result arguments.
191		248
192	=cut	249	=cut
193		250
194	sub terminate {	251	sub terminate {
195	$current->{status} = [@_];
196	$current->cancel;	252	$current->cancel (@_);
197	&schedule;
198	die; # NORETURN
199	}	253	}
200		254
201	=back	255	=back
202		256
203	# dynamic methods	257	# dynamic methods
204		258
205	=head2 PROCESS METHODS	259	=head2 COROUTINE METHODS
206		260
207	These are the methods you can call on process objects.	261	These are the methods you can call on coroutine objects.
208		262
209	=over 4	263	=over 4
210		264
211	=item new Coro \&sub [, @args...]	265	=item new Coro \&sub [, @args...]
212		266
213	Create a new process and return it. When the sub returns the process	267	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	268	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	269	called. To make the coroutine run you must first put it into the ready queue
216	by calling the ready method.	270	by calling the ready method.
217		271
218	=cut	272	Calling C<exit> in a coroutine will not work correctly, so do not do that.
219		273
		274	=cut
		275
220	sub _newcoro {	276	sub _run_coro {
221	terminate &{+shift};	277	terminate &{+shift};
222	}	278	}
223		279
224	sub new {	280	sub new {
225	my $class = shift;	281	my $class = shift;
226	bless {
227	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
228	}, $class;
229	}
230		282
231	=item $process->ready	283	$class->SUPER::new (\&_run_coro, @_)
		284	}
232		285
233	Put the given process into the ready queue.	286	=item $success = $coroutine->ready
234		287
235	=cut	288	Put the given coroutine into the ready queue (according to it's priority)
		289	and return true. If the coroutine is already in the ready queue, do nothing
		290	and return false.
236		291
237	=item $process->cancel	292	=item $is_ready = $coroutine->is_ready
238		293
239	Like C<terminate>, but terminates the specified process instead.	294	Return wether the coroutine is currently the ready queue or not,
		295
		296	=item $coroutine->cancel (arg...)
		297
		298	Terminates the given coroutine and makes it return the given arguments as
		299	status (default: the empty list).
240		300
241	=cut	301	=cut
242		302
243	sub cancel {	303	sub cancel {
		304	my $self = shift;
		305	$self->{status} = [@_];
244	push @destroy, $_[0];	306	push @destroy, $self;
245	$manager->ready;	307	$manager->ready;
246	&schedule if $current == $_[0];	308	&schedule if $current == $self;
247	}	309	}
248		310
249	=item $process->join	311	=item $coroutine->join
250		312
251	Wait until the coroutine terminates and return any values given to the	313	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	314	C<terminate> or C<cancel> functions. C<join> can be called multiple times
253	processes.	315	from multiple coroutine.
254		316
255	=cut	317	=cut
256		318
257	sub join {	319	sub join {
258	my $self = shift;	320	my $self = shift;
…		…
261	&schedule;	323	&schedule;
262	}	324	}
263	wantarray ? @{$self->{status}} : $self->{status}[0];	325	wantarray ? @{$self->{status}} : $self->{status}[0];
264	}	326	}
265		327
		328	=item $coroutine->on_destroy (\&cb)
		329
		330	Registers a callback that is called when this coroutine gets destroyed,
		331	but before it is joined. The callback gets passed the terminate arguments,
		332	if any.
		333
		334	=cut
		335
		336	sub on_destroy {
		337	my ($self, $cb) = @_;
		338
		339	push @{ $self->{destroy_cb} }, $cb;
		340	}
		341
266	=item $oldprio = $process->prio($newprio)	342	=item $oldprio = $coroutine->prio ($newprio)
267		343
268	Sets (or gets, if the argument is missing) the priority of the	344	Sets (or gets, if the argument is missing) the priority of the
269	process. Higher priority processes get run before lower priority	345	coroutine. Higher priority coroutines get run before lower priority
270	processes. Priorities are smalled signed integer (currently -4 .. +3),	346	coroutines. Priorities are small signed integers (currently -4 .. +3),
271	that you can refer to using PRIO_xxx constants (use the import tag :prio	347	that you can refer to using PRIO_xxx constants (use the import tag :prio
272	to get then):	348	to get then):
273		349
274	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	350	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
275	3 > 1 > 0 > -1 > -3 > -4	351	3 > 1 > 0 > -1 > -3 > -4
…		…
278	current->prio(PRIO_HIGH);	354	current->prio(PRIO_HIGH);
279		355
280	The idle coroutine ($Coro::idle) always has a lower priority than any	356	The idle coroutine ($Coro::idle) always has a lower priority than any
281	existing coroutine.	357	existing coroutine.
282		358
283	Changing the priority of the current process will take effect immediately,	359	Changing the priority of the current coroutine will take effect immediately,
284	but changing the priority of processes in the ready queue (but not	360	but changing the priority of coroutines in the ready queue (but not
285	running) will only take effect after the next schedule (of that	361	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.	362	coroutine). This is a bug that will be fixed in some future version.
287		363
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)	364	=item $newprio = $coroutine->nice ($change)
297		365
298	Similar to C<prio>, but subtract the given value from the priority (i.e.	366	Similar to C<prio>, but subtract the given value from the priority (i.e.
299	higher values mean lower priority, just as in unix).	367	higher values mean lower priority, just as in unix).
300		368
301	=cut
302
303	sub nice {
304	$_[0]{prio} -= $_[1];
305	}
306
307	=item $olddesc = $process->desc($newdesc)	369	=item $olddesc = $coroutine->desc ($newdesc)
308		370
309	Sets (or gets in case the argument is missing) the description for this	371	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.	372	coroutine. This is just a free-form string you can associate with a coroutine.
311		373
312	=cut	374	=cut
313		375
314	sub desc {	376	sub desc {
315	my $old = $_[0]{desc};	377	my $old = $_[0]{desc};
…		…
317	$old;	379	$old;
318	}	380	}
319		381
320	=back	382	=back
321		383
		384	=head2 GLOBAL FUNCTIONS
		385
		386	=over 4
		387
		388	=item Coro::nready
		389
		390	Returns the number of coroutines that are currently in the ready state,
		391	i.e. that can be swicthed to. The value C<0> means that the only runnable
		392	coroutine is the currently running one, so C<cede> would have no effect,
		393	and C<schedule> would cause a deadlock unless there is an idle handler
		394	that wakes up some coroutines.
		395
		396	=item unblock_sub { ... }
		397
		398	This utility function takes a BLOCK or code reference and "unblocks" it,
		399	returning the new coderef. This means that the new coderef will return
		400	immediately without blocking, returning nothing, while the original code
		401	ref will be called (with parameters) from within its own coroutine.
		402
		403	The reason this fucntion exists is that many event libraries (such as the
		404	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		405	of thread-safety). This means you must not block within event callbacks,
		406	otherwise you might suffer from crashes or worse.
		407
		408	This function allows your callbacks to block by executing them in another
		409	coroutine where it is safe to block. One example where blocking is handy
		410	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		411	disk.
		412
		413	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		414	creating event callbacks that want to block.
		415
		416	=cut
		417
		418	our @unblock_pool;
		419	our @unblock_queue;
		420	our $UNBLOCK_POOL_SIZE = 2;
		421
		422	sub unblock_handler_ {
		423	while () {
		424	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		425	$cb->(@arg);
		426
		427	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		428	push @unblock_pool, $Coro::current;
		429	schedule;
		430	}
		431	}
		432
		433	our $unblock_scheduler = async {
		434	while () {
		435	while (my $cb = pop @unblock_queue) {
		436	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		437	$handler->{arg} = $cb;
		438	$handler->ready;
		439	cede;
		440	}
		441
		442	schedule;
		443	}
		444	};
		445
		446	sub unblock_sub(&) {
		447	my $cb = shift;
		448
		449	sub {
		450	push @unblock_queue, [$cb, @_];
		451	$unblock_scheduler->ready;
		452	}
		453	}
		454
		455	=back
		456
322	=cut	457	=cut
323		458
324	1;	459	1;
325		460
326	=head1 BUGS/LIMITATIONS	461	=head1 BUGS/LIMITATIONS
327		462
328	- you must make very sure that no coro is still active on global destruction.	463	- you must make very sure that no coro is still active on global
329	very bad things might happen otherwise (usually segfaults).	464	destruction. very bad things might happen otherwise (usually segfaults).
		465
330	- this module is not thread-safe. You must only ever use this module from	466	- 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	467	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).	468	to allow per-thread schedulers, but Coro::State does not yet allow
		469	this).
333		470
334	=head1 SEE ALSO	471	=head1 SEE ALSO
335		472
336	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	473	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>,	474
338	L<Coro::Handle>, L<Coro::Socket>.	475	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		476
		477	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		478
		479	Embedding: L<Coro:MakeMaker>
339		480
340	=head1 AUTHOR	481	=head1 AUTHOR
341		482
342	Marc Lehmann <pcg@goof.com>	483	Marc Lehmann <schmorp@schmorp.de>
343	http://www.goof.com/pcg/marc/	484	http://home.schmorp.de/
344		485
345	=cut	486	=cut
346		487

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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 1.102 by root, Fri Dec 29 11:37:49 2006 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.41 by root, Tue Nov 6 20:34:09 2001 UTC vs.
Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC