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

Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.54 by pcg, Sun Sep 28 09:00:48 2003 UTC vs.
Revision 1.99 by root, Tue Dec 5 12:50:04 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
		44	use strict;
35	no warnings qw(uninitialized);	45	no warnings "uninitialized";
36		46
37	use Coro::State;	47	use Coro::State;
38		48
39	use base Exporter;	49	use base qw(Coro::State Exporter);
40		50
41	$VERSION = 0.7;	51	our $idle; # idle handler
		52	our $main; # main coroutine
		53	our $current; # current coroutine
42		54
		55	our $VERSION = '3.11';
		56
43	@EXPORT = qw(async cede schedule terminate current);	57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
44	%EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
45	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
46	);	60	);
47	@EXPORT_OK = @{$EXPORT_TAGS{prio}};	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
48		62
49	{	63	{
50	my @async;	64	my @async;
51	my $init;	65	my $init;
52		66
53	# this way of handling attributes simply is NOT scalable ;()	67	# this way of handling attributes simply is NOT scalable ;()
54	sub import {	68	sub import {
		69	no strict 'refs';
		70
55	Coro->export_to_level(1, @_);	71	Coro->export_to_level (1, @_);
		72
56	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
57	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
58	my ($package, $ref) = (shift, shift);	75	my ($package, $ref) = (shift, shift);
59	my @attrs;	76	my @attrs;
60	for (@_) {	77	for (@_) {
…		…
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;
131	$coro->{status} \|\|= [];	158	$coro->{status} \|\|= [];
132	$_->ready for @{delete $coro->{join} \|\| []};	159	$_->ready for @{delete $coro->{join} \|\| []};
133	$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);
134	}	166	}
135	&schedule;	167	&schedule;
136	}	168	}
137	};	169	};
138		170
…		…
140		172
141	=back	173	=back
142		174
143	=head2 STATIC METHODS	175	=head2 STATIC METHODS
144		176
145	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.
146		178
147	=over 4	179	=over 4
148		180
149	=item async { ... } [@args...]	181	=item async { ... } [@args...]
150		182
151	Create a new asynchronous process and return it's process object	183	Create a new asynchronous coroutine and return it's coroutine object
152	(usually unused). When the sub returns the new process is automatically	184	(usually unused). When the sub returns the new coroutine is automatically
153	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.
154		191
155	# create a new coroutine that just prints its arguments	192	# create a new coroutine that just prints its arguments
156	async {	193	async {
157	print "@_\n";	194	print "@_\n";
158	} 1,2,3,4;	195	} 1,2,3,4;
159		196
160	The coderef you submit MUST NOT be a closure that refers to variables
161	in an outer scope. This does NOT work. Pass arguments into it instead.
162
163	=cut	197	=cut
164		198
165	sub async(&@) {	199	sub async(&@) {
166	my $pid = new Coro @_;	200	my $pid = new Coro @_;
167	$manager->ready; # this ensures that the stack is cloned from the manager
168	$pid->ready;	201	$pid->ready;
169	$pid;	202	$pid
170	}	203	}
171		204
172	=item schedule	205	=item schedule
173		206
174	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
175	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
176	never be called again.	209	never be called again unless something else (e.g. an event handler) calls
		210	ready.
177		211
178	=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	}
179		230
180	=item cede	231	=item cede
181		232
182	"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
183	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
184	current "timeslice" to other coroutines of the same or higher priority.	235	current "timeslice" to other coroutines of the same or higher priority.
185		236
186	=cut
187
188	=item terminate [arg...]	237	=item terminate [arg...]
189		238
190	Terminates the current process.	239	Terminates the current coroutine with the given status values (see L<cancel>).
191
192	Future versions of this function will allow result arguments.
193		240
194	=cut	241	=cut
195		242
196	sub terminate {	243	sub terminate {
197	$current->{status} = [@_];
198	$current->cancel;	244	$current->cancel (@_);
199	&schedule;
200	die; # NORETURN
201	}	245	}
202		246
203	=back	247	=back
204		248
205	# dynamic methods	249	# dynamic methods
206		250
207	=head2 PROCESS METHODS	251	=head2 COROUTINE METHODS
208		252
209	These are the methods you can call on process objects.	253	These are the methods you can call on coroutine objects.
210		254
211	=over 4	255	=over 4
212		256
213	=item new Coro \&sub [, @args...]	257	=item new Coro \&sub [, @args...]
214		258
215	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
216	automatically terminates as if C<terminate> with the returned values were	260	automatically terminates as if C<terminate> with the returned values were
217	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
218	by calling the ready method.	262	by calling the ready method.
219		263
220	=cut	264	Calling C<exit> in a coroutine will not work correctly, so do not do that.
221		265
		266	=cut
		267
222	sub _newcoro {	268	sub _run_coro {
223	terminate &{+shift};	269	terminate &{+shift};
224	}	270	}
225		271
226	sub new {	272	sub new {
227	my $class = shift;	273	my $class = shift;
228	bless {
229	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
230	}, $class;
231	}
232		274
233	=item $process->ready	275	$class->SUPER::new (\&_run_coro, @_)
		276	}
234		277
235	Put the given process into the ready queue.	278	=item $success = $coroutine->ready
236		279
237	=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.
238		283
239	=item $process->cancel	284	=item $is_ready = $coroutine->is_ready
240		285
241	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).
242		292
243	=cut	293	=cut
244		294
245	sub cancel {	295	sub cancel {
		296	my $self = shift;
		297	$self->{status} = [@_];
246	push @destroy, $_[0];	298	push @destroy, $self;
247	$manager->ready;	299	$manager->ready;
248	&schedule if $current == $_[0];	300	&schedule if $current == $self;
249	}	301	}
250		302
251	=item $process->join	303	=item $coroutine->join
252		304
253	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
254	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
255	processes.	307	from multiple coroutine.
256		308
257	=cut	309	=cut
258		310
259	sub join {	311	sub join {
260	my $self = shift;	312	my $self = shift;
…		…
263	&schedule;	315	&schedule;
264	}	316	}
265	wantarray ? @{$self->{status}} : $self->{status}[0];	317	wantarray ? @{$self->{status}} : $self->{status}[0];
266	}	318	}
267		319
268	=item $oldprio = $process->prio($newprio)	320	=item $oldprio = $coroutine->prio ($newprio)
269		321
270	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
271	process. Higher priority processes get run before lower priority	323	coroutine. Higher priority coroutines get run before lower priority
272	processes. Priorities are small signed integers (currently -4 .. +3),	324	coroutines. Priorities are small signed integers (currently -4 .. +3),
273	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
274	to get then):	326	to get then):
275		327
276	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
277	3 > 1 > 0 > -1 > -3 > -4	329	3 > 1 > 0 > -1 > -3 > -4
…		…
280	current->prio(PRIO_HIGH);	332	current->prio(PRIO_HIGH);
281		333
282	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
283	existing coroutine.	335	existing coroutine.
284		336
285	Changing the priority of the current process will take effect immediately,	337	Changing the priority of the current coroutine will take effect immediately,
286	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
287	running) will only take effect after the next schedule (of that	339	running) will only take effect after the next schedule (of that
288	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.
289		341
290	=cut
291
292	sub prio {
293	my $old = $_[0]{prio};
294	$_[0]{prio} = $_[1] if @_ > 1;
295	$old;
296	}
297
298	=item $newprio = $process->nice($change)	342	=item $newprio = $coroutine->nice ($change)
299		343
300	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.
301	higher values mean lower priority, just as in unix).	345	higher values mean lower priority, just as in unix).
302		346
303	=cut
304
305	sub nice {
306	$_[0]{prio} -= $_[1];
307	}
308
309	=item $olddesc = $process->desc($newdesc)	347	=item $olddesc = $coroutine->desc ($newdesc)
310		348
311	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
312	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.
313		351
314	=cut	352	=cut
315		353
316	sub desc {	354	sub desc {
317	my $old = $_[0]{desc};	355	my $old = $_[0]{desc};
…		…
319	$old;	357	$old;
320	}	358	}
321		359
322	=back	360	=back
323		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
324	=cut	435	=cut
325		436
326	1;	437	1;
327		438
328	=head1 BUGS/LIMITATIONS	439	=head1 BUGS/LIMITATIONS
…		…
335	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
336	this).	447	this).
337		448
338	=head1 SEE ALSO	449	=head1 SEE ALSO
339		450
340	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>.
341	L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,	452
342	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>
343		458
344	=head1 AUTHOR	459	=head1 AUTHOR
345		460
346	Marc Lehmann <pcg@goof.com>	461	Marc Lehmann <schmorp@schmorp.de>
347	http://www.goof.com/pcg/marc/	462	http://home.schmorp.de/
348		463
349	=cut	464	=cut
350		465

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Comparing cvsroot/Coro/Coro.pm (file contents): Revision 1.54 by pcg, Sun Sep 28 09:00:48 2003 UTC vs. Revision 1.99 by root, Tue Dec 5 12:50:04 2006 UTC

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Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.54 by pcg, Sun Sep 28 09:00:48 2003 UTC vs.
Revision 1.99 by root, Tue Dec 5 12:50:04 2006 UTC