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

Comparing Coro/Coro.pm (file contents):
Revision 1.56 by pcg, Sat Nov 15 03:53:10 2003 UTC vs.
Revision 1.98 by root, Mon Dec 4 21:56:00 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 = "0.9";	55	our $VERSION = '3.1';
44		56
45	@EXPORT = qw(async cede schedule terminate current);	57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
46	%EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48	);	60	);
49	@EXPORT_OK = @{$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;
133	$coro->{status} \|\|= [];	158	$coro->{status} \|\|= [];
134	$_->ready for @{delete $coro->{join} \|\| []};	159	$_->ready for @{delete $coro->{join} \|\| []};
135	$coro->{_coro_state} = $manager->{_coro_state};	160
		161	# the next line destroys the coro state, but keeps the
		162	# coroutine itself intact (we basically make it a zombie
		163	# coroutine that always runs the manager thread, so it's possible
		164	# to transfer() to this coroutine).
		165	$coro->_clone_state_from ($manager);
136	}	166	}
137	&schedule;	167	&schedule;
138	}	168	}
139	};	169	};
140		170
…		…
142		172
143	=back	173	=back
144		174
145	=head2 STATIC METHODS	175	=head2 STATIC METHODS
146		176
147	Static methods are actually functions that operate on the current process only.	177	Static methods are actually functions that operate on the current coroutine only.
148		178
149	=over 4	179	=over 4
150		180
151	=item async { ... } [@args...]	181	=item async { ... } [@args...]
152		182
153	Create a new asynchronous process and return it's process object	183	Create a new asynchronous coroutine and return it's coroutine object
154	(usually unused). When the sub returns the new process is automatically	184	(usually unused). When the sub returns the new coroutine is automatically
155	terminated.	185	terminated.
		186
		187	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		188
		189	When the coroutine dies, the program will exit, just as in the main
		190	program.
156		191
157	# create a new coroutine that just prints its arguments	192	# create a new coroutine that just prints its arguments
158	async {	193	async {
159	print "@_\n";	194	print "@_\n";
160	} 1,2,3,4;	195	} 1,2,3,4;
161		196
162	The coderef you submit MUST NOT be a closure that refers to variables
163	in an outer scope. This does NOT work. Pass arguments into it instead.
164
165	=cut	197	=cut
166		198
167	sub async(&@) {	199	sub async(&@) {
168	my $pid = new Coro @_;	200	my $pid = new Coro @_;
169	$manager->ready; # this ensures that the stack is cloned from the manager
170	$pid->ready;	201	$pid->ready;
171	$pid;	202	$pid
172	}	203	}
173		204
174	=item schedule	205	=item schedule
175		206
176	Calls the scheduler. Please note that the current process will not be put	207	Calls the scheduler. Please note that the current coroutine will not be put
177	into the ready queue, so calling this function usually means you will	208	into the ready queue, so calling this function usually means you will
178	never be called again.	209	never be called again unless something else (e.g. an event handler) calls
		210	ready.
179		211
180	=cut	212	The canonical way to wait on external events is this:
		213
		214	{
		215	# remember current coroutine
		216	my $current = $Coro::current;
		217
		218	# register a hypothetical event handler
		219	on_event_invoke sub {
		220	# wake up sleeping coroutine
		221	$current->ready;
		222	undef $current;
		223	};
		224
		225	# call schedule until event occured.
		226	# in case we are woken up for other reasons
		227	# (current still defined), loop.
		228	Coro::schedule while $current;
		229	}
181		230
182	=item cede	231	=item cede
183		232
184	"Cede" to other processes. This function puts the current process into the	233	"Cede" to other coroutines. This function puts the current coroutine into the
185	ready queue and calls C<schedule>, which has the effect of giving up the	234	ready queue and calls C<schedule>, which has the effect of giving up the
186	current "timeslice" to other coroutines of the same or higher priority.	235	current "timeslice" to other coroutines of the same or higher priority.
187		236
188	=cut
189
190	=item terminate [arg...]	237	=item terminate [arg...]
191		238
192	Terminates the current process.	239	Terminates the current coroutine with the given status values (see L<cancel>).
193
194	Future versions of this function will allow result arguments.
195		240
196	=cut	241	=cut
197		242
198	sub terminate {	243	sub terminate {
199	$current->{status} = [@_];
200	$current->cancel;	244	$current->cancel (@_);
201	&schedule;
202	die; # NORETURN
203	}	245	}
204		246
205	=back	247	=back
206		248
207	# dynamic methods	249	# dynamic methods
208		250
209	=head2 PROCESS METHODS	251	=head2 COROUTINE METHODS
210		252
211	These are the methods you can call on process objects.	253	These are the methods you can call on coroutine objects.
212		254
213	=over 4	255	=over 4
214		256
215	=item new Coro \&sub [, @args...]	257	=item new Coro \&sub [, @args...]
216		258
217	Create a new process and return it. When the sub returns the process	259	Create a new coroutine and return it. When the sub returns the coroutine
218	automatically terminates as if C<terminate> with the returned values were	260	automatically terminates as if C<terminate> with the returned values were
219	called. To make the process run you must first put it into the ready queue	261	called. To make the coroutine run you must first put it into the ready queue
220	by calling the ready method.	262	by calling the ready method.
221		263
222	=cut	264	Calling C<exit> in a coroutine will not work correctly, so do not do that.
223		265
		266	=cut
		267
224	sub _newcoro {	268	sub _run_coro {
225	terminate &{+shift};	269	terminate &{+shift};
226	}	270	}
227		271
228	sub new {	272	sub new {
229	my $class = shift;	273	my $class = shift;
230	bless {
231	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
232	}, $class;
233	}
234		274
235	=item $process->ready	275	$class->SUPER::new (\&_run_coro, @_)
		276	}
236		277
237	Put the given process into the ready queue.	278	=item $success = $coroutine->ready
238		279
239	=cut	280	Put the given coroutine into the ready queue (according to it's priority)
		281	and return true. If the coroutine is already in the ready queue, do nothing
		282	and return false.
240		283
241	=item $process->cancel	284	=item $is_ready = $coroutine->is_ready
242		285
243	Like C<terminate>, but terminates the specified process instead.	286	Return wether the coroutine is currently the ready queue or not,
		287
		288	=item $coroutine->cancel (arg...)
		289
		290	Terminates the given coroutine and makes it return the given arguments as
		291	status (default: the empty list).
244		292
245	=cut	293	=cut
246		294
247	sub cancel {	295	sub cancel {
		296	my $self = shift;
		297	$self->{status} = [@_];
248	push @destroy, $_[0];	298	push @destroy, $self;
249	$manager->ready;	299	$manager->ready;
250	&schedule if $current == $_[0];	300	&schedule if $current == $self;
251	}	301	}
252		302
253	=item $process->join	303	=item $coroutine->join
254		304
255	Wait until the coroutine terminates and return any values given to the	305	Wait until the coroutine terminates and return any values given to the
256	C<terminate> function. C<join> can be called multiple times from multiple	306	C<terminate> or C<cancel> functions. C<join> can be called multiple times
257	processes.	307	from multiple coroutine.
258		308
259	=cut	309	=cut
260		310
261	sub join {	311	sub join {
262	my $self = shift;	312	my $self = shift;
…		…
265	&schedule;	315	&schedule;
266	}	316	}
267	wantarray ? @{$self->{status}} : $self->{status}[0];	317	wantarray ? @{$self->{status}} : $self->{status}[0];
268	}	318	}
269		319
270	=item $oldprio = $process->prio($newprio)	320	=item $oldprio = $coroutine->prio ($newprio)
271		321
272	Sets (or gets, if the argument is missing) the priority of the	322	Sets (or gets, if the argument is missing) the priority of the
273	process. Higher priority processes get run before lower priority	323	coroutine. Higher priority coroutines get run before lower priority
274	processes. Priorities are small signed integers (currently -4 .. +3),	324	coroutines. Priorities are small signed integers (currently -4 .. +3),
275	that you can refer to using PRIO_xxx constants (use the import tag :prio	325	that you can refer to using PRIO_xxx constants (use the import tag :prio
276	to get then):	326	to get then):
277		327
278	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	328	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
279	3 > 1 > 0 > -1 > -3 > -4	329	3 > 1 > 0 > -1 > -3 > -4
…		…
282	current->prio(PRIO_HIGH);	332	current->prio(PRIO_HIGH);
283		333
284	The idle coroutine ($Coro::idle) always has a lower priority than any	334	The idle coroutine ($Coro::idle) always has a lower priority than any
285	existing coroutine.	335	existing coroutine.
286		336
287	Changing the priority of the current process will take effect immediately,	337	Changing the priority of the current coroutine will take effect immediately,
288	but changing the priority of processes in the ready queue (but not	338	but changing the priority of coroutines in the ready queue (but not
289	running) will only take effect after the next schedule (of that	339	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.	340	coroutine). This is a bug that will be fixed in some future version.
291		341
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)	342	=item $newprio = $coroutine->nice ($change)
301		343
302	Similar to C<prio>, but subtract the given value from the priority (i.e.	344	Similar to C<prio>, but subtract the given value from the priority (i.e.
303	higher values mean lower priority, just as in unix).	345	higher values mean lower priority, just as in unix).
304		346
305	=cut
306
307	sub nice {
308	$_[0]{prio} -= $_[1];
309	}
310
311	=item $olddesc = $process->desc($newdesc)	347	=item $olddesc = $coroutine->desc ($newdesc)
312		348
313	Sets (or gets in case the argument is missing) the description for this	349	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.	350	coroutine. This is just a free-form string you can associate with a coroutine.
315		351
316	=cut	352	=cut
317		353
318	sub desc {	354	sub desc {
319	my $old = $_[0]{desc};	355	my $old = $_[0]{desc};
…		…
321	$old;	357	$old;
322	}	358	}
323		359
324	=back	360	=back
325		361
		362	=head2 GLOBAL FUNCTIONS
		363
		364	=over 4
		365
		366	=item Coro::nready
		367
		368	Returns the number of coroutines that are currently in the ready state,
		369	i.e. that can be swicthed to. The value C<0> means that the only runnable
		370	coroutine is the currently running one, so C<cede> would have no effect,
		371	and C<schedule> would cause a deadlock unless there is an idle handler
		372	that wakes up some coroutines.
		373
		374	=item unblock_sub { ... }
		375
		376	This utility function takes a BLOCK or code reference and "unblocks" it,
		377	returning the new coderef. This means that the new coderef will return
		378	immediately without blocking, returning nothing, while the original code
		379	ref will be called (with parameters) from within its own coroutine.
		380
		381	The reason this fucntion exists is that many event libraries (such as the
		382	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		383	of thread-safety). This means you must not block within event callbacks,
		384	otherwise you might suffer from crashes or worse.
		385
		386	This function allows your callbacks to block by executing them in another
		387	coroutine where it is safe to block. One example where blocking is handy
		388	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		389	disk.
		390
		391	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		392	creating event callbacks that want to block.
		393
		394	=cut
		395
		396	our @unblock_pool;
		397	our @unblock_queue;
		398	our $UNBLOCK_POOL_SIZE = 2;
		399
		400	sub unblock_handler_ {
		401	while () {
		402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		403	$cb->(@arg);
		404
		405	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		406	push @unblock_pool, $Coro::current;
		407	schedule;
		408	}
		409	}
		410
		411	our $unblock_scheduler = async {
		412	while () {
		413	while (my $cb = pop @unblock_queue) {
		414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		415	$handler->{arg} = $cb;
		416	$handler->ready;
		417	cede;
		418	}
		419
		420	schedule;
		421	}
		422	};
		423
		424	sub unblock_sub(&) {
		425	my $cb = shift;
		426
		427	sub {
		428	push @unblock_queue, [$cb, @_];
		429	$unblock_scheduler->ready;
		430	}
		431	}
		432
		433	=back
		434
326	=cut	435	=cut
327		436
328	1;	437	1;
329		438
330	=head1 BUGS/LIMITATIONS	439	=head1 BUGS/LIMITATIONS
…		…
337	to allow per-thread schedulers, but Coro::State does not yet allow	446	to allow per-thread schedulers, but Coro::State does not yet allow
338	this).	447	this).
339		448
340	=head1 SEE ALSO	449	=head1 SEE ALSO
341		450
342	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	451	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>,	452
344	L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>.	453	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		454
		455	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		456
		457	Embedding: L<Coro:MakeMaker>
345		458
346	=head1 AUTHOR	459	=head1 AUTHOR
347		460
348	Marc Lehmann <pcg@goof.com>	461	Marc Lehmann <schmorp@schmorp.de>
349	http://www.goof.com/pcg/marc/	462	http://home.schmorp.de/
350		463
351	=cut	464	=cut
352		465

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Comparing Coro/Coro.pm (file contents): Revision 1.56 by pcg, Sat Nov 15 03:53:10 2003 UTC vs. Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.56 by pcg, Sat Nov 15 03:53:10 2003 UTC vs.
Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC