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

Comparing Coro/Coro.pm (file contents):
Revision 1.39 by root, Tue Oct 9 00:39:08 2001 UTC vs.
Revision 1.92 by root, Fri Dec 1 03:47:55 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 = 0.51;	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) {	110	if ($current) {
98	$main->{specific} = $current->{specific};	111	$main->{specific} = $current->{specific};
99	}	112	}
100		113
101	our $current = $main;	114	$current = $main;
102		115
103	sub current() { $current }	116	sub current() { $current }
104		117
105	=item $idle	118	=item $idle
106		119
107	The coroutine to switch to when no other coroutine is running. The default	120	A callback that is called whenever the scheduler finds no ready coroutines
108	implementation prints "FATAL: deadlock detected" and exits.	121	to run. The default implementation prints "FATAL: deadlock detected" and
		122	exits, because the program has no other way to continue.
109		123
110	=cut	124	This hook is overwritten by modules such as C<Coro::Timer> and
		125	C<Coro::Event> to wait on an external event that hopefully wake up a
		126	coroutine so the scheduler can run it.
111		127
112	# should be done using priorities :(	128	Please note that if your callback recursively invokes perl (e.g. for event
113	our $idle = new Coro sub {	129	handlers), then it must be prepared to be called recursively.
		130
		131	=cut
		132
		133	$idle = sub {
114	print STDERR "FATAL: deadlock detected\n";	134	print STDERR "FATAL: deadlock detected\n";
115	exit(51);	135	exit (51);
116	};	136	};
117		137
118	# this coroutine is necessary because a coroutine	138	# this coroutine is necessary because a coroutine
119	# cannot destroy itself.	139	# cannot destroy itself.
120	my @destroy;	140	my @destroy;
121	my $manager;
122	$manager = new Coro sub {	141	my $manager; $manager = new Coro sub {
123	while() {	142	while () {
124	# by overwriting the state object with the manager we destroy it	143	# by overwriting the state object with the manager we destroy it
125	# while still being able to schedule this coroutine (in case it has	144	# while still being able to schedule this coroutine (in case it has
126	# been readied multiple times. this is harmless since the manager	145	# been readied multiple times. this is harmless since the manager
127	# can be called as many times as neccessary and will always	146	# can be called as many times as neccessary and will always
128	# remove itself from the runqueue	147	# remove itself from the runqueue
129	(pop @destroy)->{_coro_state} = $manager->{_coro_state} while @destroy;	148	while (@destroy) {
		149	my $coro = pop @destroy;
		150	$coro->{status} \|\|= [];
		151	$_->ready for @{delete $coro->{join} \|\| []};
		152
		153	# the next line destroys the coro state, but keeps the
		154	# coroutine itself intact (we basically make it a zombie
		155	# coroutine that always runs the manager thread, so it's possible
		156	# to transfer() to this coroutine).
		157	$coro->_clone_state_from ($manager);
		158	}
130	&schedule;	159	&schedule;
131	}	160	}
132	};	161	};
133		162
134	# static methods. not really.	163	# static methods. not really.
135		164
		165	=back
		166
136	=head2 STATIC METHODS	167	=head2 STATIC METHODS
137		168
138	Static methods are actually functions that operate on the current process only.	169	Static methods are actually functions that operate on the current coroutine only.
139		170
140	=over 4	171	=over 4
141		172
142	=item async { ... } [@args...]	173	=item async { ... } [@args...]
143		174
144	Create a new asynchronous process and return it's process object	175	Create a new asynchronous coroutine and return it's coroutine object
145	(usually unused). When the sub returns the new process is automatically	176	(usually unused). When the sub returns the new coroutine is automatically
146	terminated.	177	terminated.
		178
		179	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		180
		181	When the coroutine dies, the program will exit, just as in the main
		182	program.
147		183
148	# create a new coroutine that just prints its arguments	184	# create a new coroutine that just prints its arguments
149	async {	185	async {
150	print "@_\n";	186	print "@_\n";
151	} 1,2,3,4;	187	} 1,2,3,4;
152		188
153	The coderef you submit MUST NOT be a closure that refers to variables
154	in an outer scope. This does NOT work. Pass arguments into it instead.
155
156	=cut	189	=cut
157		190
158	sub async(&@) {	191	sub async(&@) {
159	my $pid = new Coro @_;	192	my $pid = new Coro @_;
160	$manager->ready; # this ensures that the stack is cloned from the manager
161	$pid->ready;	193	$pid->ready;
162	$pid;	194	$pid
163	}	195	}
164		196
165	=item schedule	197	=item schedule
166		198
167	Calls the scheduler. Please note that the current process will not be put	199	Calls the scheduler. Please note that the current coroutine will not be put
168	into the ready queue, so calling this function usually means you will	200	into the ready queue, so calling this function usually means you will
169	never be called again.	201	never be called again unless something else (e.g. an event handler) calls
		202	ready.
170		203
171	=cut	204	The canonical way to wait on external events is this:
		205
		206	{
		207	# remember current coroutine
		208	my $current = $Coro::current;
		209
		210	# register a hypothetical event handler
		211	on_event_invoke sub {
		212	# wake up sleeping coroutine
		213	$current->ready;
		214	undef $current;
		215	};
		216
		217	# call schedule until event occured.
		218	# in case we are woken up for other reasons
		219	# (current still defined), loop.
		220	Coro::schedule while $current;
		221	}
172		222
173	=item cede	223	=item cede
174		224
175	"Cede" to other processes. This function puts the current process into the	225	"Cede" to other coroutines. This function puts the current coroutine into the
176	ready queue and calls C<schedule>, which has the effect of giving up the	226	ready queue and calls C<schedule>, which has the effect of giving up the
177	current "timeslice" to other coroutines of the same or higher priority.	227	current "timeslice" to other coroutines of the same or higher priority.
178		228
179	=cut
180
181	=item terminate	229	=item terminate [arg...]
182		230
183	Terminates the current process.	231	Terminates the current coroutine with the given status values (see L<cancel>).
184
185	Future versions of this function will allow result arguments.
186		232
187	=cut	233	=cut
188		234
189	sub terminate {	235	sub terminate {
190	$current->cancel;	236	$current->cancel (@_);
191	&schedule;
192	die; # NORETURN
193	}	237	}
194		238
195	=back	239	=back
196		240
197	# dynamic methods	241	# dynamic methods
198		242
199	=head2 PROCESS METHODS	243	=head2 COROUTINE METHODS
200		244
201	These are the methods you can call on process objects.	245	These are the methods you can call on coroutine objects.
202		246
203	=over 4	247	=over 4
204		248
205	=item new Coro \&sub [, @args...]	249	=item new Coro \&sub [, @args...]
206		250
207	Create a new process and return it. When the sub returns the process	251	Create a new coroutine and return it. When the sub returns the coroutine
208	automatically terminates. To start the process you must first put it into	252	automatically terminates as if C<terminate> with the returned values were
		253	called. To make the coroutine run you must first put it into the ready queue
209	the ready queue by calling the ready method.	254	by calling the ready method.
210		255
211	The coderef you submit MUST NOT be a closure that refers to variables	256	Calling C<exit> in a coroutine will not work correctly, so do not do that.
212	in an outer scope. This does NOT work. Pass arguments into it instead.
213		257
214	=cut	258	=cut
215		259
216	sub _newcoro {	260	sub _new_coro {
217	terminate &{+shift};	261	terminate &{+shift};
218	}	262	}
219		263
220	sub new {	264	sub new {
221	my $class = shift;	265	my $class = shift;
222	bless {
223	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
224	}, $class;
225	}
226		266
227	=item $process->ready	267	$class->SUPER::new (\&_new_coro, @_)
		268	}
228		269
229	Put the given process into the ready queue.	270	=item $success = $coroutine->ready
230		271
231	=cut	272	Put the given coroutine into the ready queue (according to it's priority)
		273	and return true. If the coroutine is already in the ready queue, do nothing
		274	and return false.
232		275
233	=item $process->cancel	276	=item $is_ready = $coroutine->is_ready
234		277
235	Like C<terminate>, but terminates the specified process instead.	278	Return wether the coroutine is currently the ready queue or not,
		279
		280	=item $coroutine->cancel (arg...)
		281
		282	Terminates the given coroutine and makes it return the given arguments as
		283	status (default: the empty list).
236		284
237	=cut	285	=cut
238		286
239	sub cancel {	287	sub cancel {
		288	my $self = shift;
		289	$self->{status} = [@_];
240	push @destroy, $_[0];	290	push @destroy, $self;
241	$manager->ready;	291	$manager->ready;
242	&schedule if $current == $_[0];	292	&schedule if $current == $self;
243	}	293	}
244		294
		295	=item $coroutine->join
		296
		297	Wait until the coroutine terminates and return any values given to the
		298	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		299	from multiple coroutine.
		300
		301	=cut
		302
		303	sub join {
		304	my $self = shift;
		305	unless ($self->{status}) {
		306	push @{$self->{join}}, $current;
		307	&schedule;
		308	}
		309	wantarray ? @{$self->{status}} : $self->{status}[0];
		310	}
		311
245	=item $oldprio = $process->prio($newprio)	312	=item $oldprio = $coroutine->prio ($newprio)
246		313
247	Sets the priority of the process. Higher priority processes get run before	314	Sets (or gets, if the argument is missing) the priority of the
248	lower priority processes. Priorities are smalled signed integer (currently	315	coroutine. Higher priority coroutines get run before lower priority
		316	coroutines. Priorities are small signed integers (currently -4 .. +3),
249	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import	317	that you can refer to using PRIO_xxx constants (use the import tag :prio
250	tag :prio to get then):	318	to get then):
251		319
252	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	320	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
253	3 > 1 > 0 > -1 > -3 > -4	321	3 > 1 > 0 > -1 > -3 > -4
254		322
255	# set priority to HIGH	323	# set priority to HIGH
256	current->prio(PRIO_HIGH);	324	current->prio(PRIO_HIGH);
257		325
258	The idle coroutine ($Coro::idle) always has a lower priority than any	326	The idle coroutine ($Coro::idle) always has a lower priority than any
259	existing coroutine.	327	existing coroutine.
260		328
261	Changing the priority of the current process will take effect immediately,	329	Changing the priority of the current coroutine will take effect immediately,
262	but changing the priority of processes in the ready queue (but not	330	but changing the priority of coroutines in the ready queue (but not
263	running) will only take effect after the next schedule (of that	331	running) will only take effect after the next schedule (of that
264	process). This is a bug that will be fixed in some future version.	332	coroutine). This is a bug that will be fixed in some future version.
265		333
266	=cut
267
268	sub prio {
269	my $old = $_[0]{prio};
270	$_[0]{prio} = $_[1] if @_ > 1;
271	$old;
272	}
273
274	=item $newprio = $process->nice($change)	334	=item $newprio = $coroutine->nice ($change)
275		335
276	Similar to C<prio>, but subtract the given value from the priority (i.e.	336	Similar to C<prio>, but subtract the given value from the priority (i.e.
277	higher values mean lower priority, just as in unix).	337	higher values mean lower priority, just as in unix).
278		338
279	=cut	339	=item $olddesc = $coroutine->desc ($newdesc)
280		340
281	sub nice {	341	Sets (or gets in case the argument is missing) the description for this
282	$_[0]{prio} -= $_[1];	342	coroutine. This is just a free-form string you can associate with a coroutine.
		343
		344	=cut
		345
		346	sub desc {
		347	my $old = $_[0]{desc};
		348	$_[0]{desc} = $_[1] if @_ > 1;
		349	$old;
283	}	350	}
284		351
285	=back	352	=back
286		353
		354	=head2 UTILITY FUNCTIONS
		355
		356	=over 4
		357
		358	=item unblock_sub { ... }
		359
		360	This utility function takes a BLOCK or code reference and "unblocks" it,
		361	returning the new coderef. This means that the new coderef will return
		362	immediately without blocking, returning nothing, while the original code
		363	ref will be called (with parameters) from within its own coroutine.
		364
		365	The reason this fucntion exists is that many event libraries (such as the
		366	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		367	of thread-safety). This means you must not block within event callbacks,
		368	otherwise you might suffer from crashes or worse.
		369
		370	This function allows your callbacks to block by executing them in another
		371	coroutine where it is safe to block. One example where blocking is handy
		372	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		373	disk.
		374
		375	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		376	creating event callbacks that want to block.
		377
		378	=cut
		379
		380	our @unblock_pool;
		381	our @unblock_queue;
		382	our $UNBLOCK_POOL_SIZE = 2;
		383
		384	sub unblock_handler_ {
		385	while () {
		386	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		387	$cb->(@arg);
		388
		389	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		390	push @unblock_pool, $Coro::current;
		391	schedule;
		392	}
		393	}
		394
		395	our $unblock_scheduler = async {
		396	while () {
		397	while (my $cb = pop @unblock_queue) {
		398	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		399	$handler->{arg} = $cb;
		400	$handler->ready;
		401	cede;
		402	}
		403
		404	schedule;
		405	}
		406	};
		407
		408	sub unblock_sub(&) {
		409	my $cb = shift;
		410
		411	sub {
		412	push @unblock_queue, [$cb, @_];
		413	$unblock_scheduler->ready;
		414	}
		415	}
		416
		417	=back
		418
287	=cut	419	=cut
288		420
289	1;	421	1;
290		422
291	=head1 BUGS/LIMITATIONS	423	=head1 BUGS/LIMITATIONS
292		424
293	- you must make very sure that no coro is still active on global destruction.	425	- you must make very sure that no coro is still active on global
294	very bad things might happen otherwise (usually segfaults).	426	destruction. very bad things might happen otherwise (usually segfaults).
		427
295	- this module is not thread-safe. You must only ever use this module from	428	- this module is not thread-safe. You should only ever use this module
296	the same thread (this requirement might be loosened in the future to	429	from the same thread (this requirement might be losened in the future
297	allow per-thread schedulers, but Coro::State does not yet allow this).	430	to allow per-thread schedulers, but Coro::State does not yet allow
		431	this).
298		432
299	=head1 SEE ALSO	433	=head1 SEE ALSO
300		434
301	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	435	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
302	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,	436
303	L<Coro::Handle>, L<Coro::Socket>.	437	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		438
		439	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		440
		441	Embedding: L<Coro:MakeMaker>
304		442
305	=head1 AUTHOR	443	=head1 AUTHOR
306		444
307	Marc Lehmann <pcg@goof.com>	445	Marc Lehmann <schmorp@schmorp.de>
308	http://www.goof.com/pcg/marc/	446	http://home.schmorp.de/
309		447
310	=cut	448	=cut
311		449

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Comparing Coro/Coro.pm (file contents): Revision 1.39 by root, Tue Oct 9 00:39:08 2001 UTC vs. Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.39 by root, Tue Oct 9 00:39:08 2001 UTC vs.
Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC