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

Comparing Coro/Coro.pm (file contents):
Revision 1.36 by root, Mon Sep 24 01:36:20 2001 UTC vs.
Revision 1.97 by root, Mon Dec 4 13:47:56 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 = 0.5;	42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
44		45
		46	our $VERSION = '3.01';
		47
45	@EXPORT = qw(async cede schedule terminate current);	48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
46	%EXPORT_TAGS = (	49	our %EXPORT_TAGS = (
47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48	);	51	);
49	@EXPORT_OK = @{$EXPORT_TAGS{prio}};	52	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
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) {
98	$main->{specific} = $current->{specific};	110	$main->{specific} = $current->{specific}
99	}	111	if $current;
100		112
101	our $current = $main;	113	_set_current $main;
102		114
103	sub current() { $current }	115	sub current() { $current }
104		116
105	=item $idle	117	=item $idle
106		118
107	The coroutine to switch to when no other coroutine is running. The default	119	A callback that is called whenever the scheduler finds no ready coroutines
108	implementation prints "FATAL: deadlock detected" and exits.	120	to run. The default implementation prints "FATAL: deadlock detected" and
		121	exits, because the program has no other way to continue.
109		122
110	=cut	123	This hook is overwritten by modules such as C<Coro::Timer> and
		124	C<Coro::Event> to wait on an external event that hopefully wake up a
		125	coroutine so the scheduler can run it.
111		126
112	# should be done using priorities :(	127	Please note that if your callback recursively invokes perl (e.g. for event
113	our $idle = new Coro sub {	128	handlers), then it must be prepared to be called recursively.
114	print STDERR "FATAL: deadlock detected\n";	129
115	exit(51);	130	=cut
		131
		132	$idle = sub {
		133	require Carp;
		134	Carp::croak ("FATAL: deadlock detected");
116	};	135	};
117		136
118	# this coroutine is necessary because a coroutine	137	# this coroutine is necessary because a coroutine
119	# cannot destroy itself.	138	# cannot destroy itself.
120	my @destroy;	139	my @destroy;
121	my $manager = new Coro sub {	140	my $manager; $manager = new Coro sub {
122	while() {	141	while () {
123	delete ((pop @destroy)->{_coro_state}) while @destroy;	142	# by overwriting the state object with the manager we destroy it
		143	# while still being able to schedule this coroutine (in case it has
		144	# been readied multiple times. this is harmless since the manager
		145	# can be called as many times as neccessary and will always
		146	# remove itself from the runqueue
		147	while (@destroy) {
		148	my $coro = pop @destroy;
		149	$coro->{status} \|\|= [];
		150	$_->ready for @{delete $coro->{join} \|\| []};
		151
		152	# the next line destroys the coro state, but keeps the
		153	# coroutine itself intact (we basically make it a zombie
		154	# coroutine that always runs the manager thread, so it's possible
		155	# to transfer() to this coroutine).
		156	$coro->_clone_state_from ($manager);
		157	}
124	&schedule;	158	&schedule;
125	}	159	}
126	};	160	};
127		161
128	# static methods. not really.	162	# static methods. not really.
129		163
		164	=back
		165
130	=head2 STATIC METHODS	166	=head2 STATIC METHODS
131		167
132	Static methods are actually functions that operate on the current process only.	168	Static methods are actually functions that operate on the current coroutine only.
133		169
134	=over 4	170	=over 4
135		171
136	=item async { ... } [@args...]	172	=item async { ... } [@args...]
137		173
138	Create a new asynchronous process and return it's process object	174	Create a new asynchronous coroutine and return it's coroutine object
139	(usually unused). When the sub returns the new process is automatically	175	(usually unused). When the sub returns the new coroutine is automatically
140	terminated.	176	terminated.
		177
		178	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		179
		180	When the coroutine dies, the program will exit, just as in the main
		181	program.
141		182
142	# create a new coroutine that just prints its arguments	183	# create a new coroutine that just prints its arguments
143	async {	184	async {
144	print "@_\n";	185	print "@_\n";
145	} 1,2,3,4;	186	} 1,2,3,4;
146		187
147	The coderef you submit MUST NOT be a closure that refers to variables
148	in an outer scope. This does NOT work. Pass arguments into it instead.
149
150	=cut	188	=cut
151		189
152	sub async(&@) {	190	sub async(&@) {
153	my $pid = new Coro @_;	191	my $pid = new Coro @_;
154	$manager->ready; # this ensures that the stack is cloned from the manager
155	$pid->ready;	192	$pid->ready;
156	$pid;	193	$pid
157	}	194	}
158		195
159	=item schedule	196	=item schedule
160		197
161	Calls the scheduler. Please note that the current process will not be put	198	Calls the scheduler. Please note that the current coroutine will not be put
162	into the ready queue, so calling this function usually means you will	199	into the ready queue, so calling this function usually means you will
163	never be called again.	200	never be called again unless something else (e.g. an event handler) calls
		201	ready.
164		202
165	=cut	203	The canonical way to wait on external events is this:
		204
		205	{
		206	# remember current coroutine
		207	my $current = $Coro::current;
		208
		209	# register a hypothetical event handler
		210	on_event_invoke sub {
		211	# wake up sleeping coroutine
		212	$current->ready;
		213	undef $current;
		214	};
		215
		216	# call schedule until event occured.
		217	# in case we are woken up for other reasons
		218	# (current still defined), loop.
		219	Coro::schedule while $current;
		220	}
166		221
167	=item cede	222	=item cede
168		223
169	"Cede" to other processes. This function puts the current process into the	224	"Cede" to other coroutines. This function puts the current coroutine into the
170	ready queue and calls C<schedule>, which has the effect of giving up the	225	ready queue and calls C<schedule>, which has the effect of giving up the
171	current "timeslice" to other coroutines of the same or higher priority.	226	current "timeslice" to other coroutines of the same or higher priority.
172		227
173	=cut
174
175	=item terminate	228	=item terminate [arg...]
176		229
177	Terminates the current process.	230	Terminates the current coroutine with the given status values (see L<cancel>).
178
179	Future versions of this function will allow result arguments.
180		231
181	=cut	232	=cut
182		233
183	sub terminate {	234	sub terminate {
184	$current->cancel;	235	$current->cancel (@_);
185	&schedule;
186	die; # NORETURN
187	}	236	}
188		237
189	=back	238	=back
190		239
191	# dynamic methods	240	# dynamic methods
192		241
193	=head2 PROCESS METHODS	242	=head2 COROUTINE METHODS
194		243
195	These are the methods you can call on process objects.	244	These are the methods you can call on coroutine objects.
196		245
197	=over 4	246	=over 4
198		247
199	=item new Coro \&sub [, @args...]	248	=item new Coro \&sub [, @args...]
200		249
201	Create a new process and return it. When the sub returns the process	250	Create a new coroutine and return it. When the sub returns the coroutine
202	automatically terminates. To start the process you must first put it into	251	automatically terminates as if C<terminate> with the returned values were
		252	called. To make the coroutine run you must first put it into the ready queue
203	the ready queue by calling the ready method.	253	by calling the ready method.
204		254
205	The coderef you submit MUST NOT be a closure that refers to variables	255	Calling C<exit> in a coroutine will not work correctly, so do not do that.
206	in an outer scope. This does NOT work. Pass arguments into it instead.
207		256
208	=cut	257	=cut
209		258
210	sub _newcoro {	259	sub _run_coro {
211	terminate &{+shift};	260	terminate &{+shift};
212	}	261	}
213		262
214	sub new {	263	sub new {
215	my $class = shift;	264	my $class = shift;
216	bless {
217	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
218	}, $class;
219	}
220		265
221	=item $process->ready	266	$class->SUPER::new (\&_run_coro, @_)
		267	}
222		268
223	Put the current process into the ready queue.	269	=item $success = $coroutine->ready
224		270
225	=cut	271	Put the given coroutine into the ready queue (according to it's priority)
		272	and return true. If the coroutine is already in the ready queue, do nothing
		273	and return false.
226		274
227	=item $process->cancel	275	=item $is_ready = $coroutine->is_ready
228		276
229	Like C<terminate>, but terminates the specified process instead.	277	Return wether the coroutine is currently the ready queue or not,
		278
		279	=item $coroutine->cancel (arg...)
		280
		281	Terminates the given coroutine and makes it return the given arguments as
		282	status (default: the empty list).
230		283
231	=cut	284	=cut
232		285
233	sub cancel {	286	sub cancel {
		287	my $self = shift;
		288	$self->{status} = [@_];
234	push @destroy, $_[0];	289	push @destroy, $self;
235	$manager->ready;	290	$manager->ready;
236	&schedule if $current == $_[0];	291	&schedule if $current == $self;
237	}	292	}
238		293
		294	=item $coroutine->join
		295
		296	Wait until the coroutine terminates and return any values given to the
		297	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		298	from multiple coroutine.
		299
		300	=cut
		301
		302	sub join {
		303	my $self = shift;
		304	unless ($self->{status}) {
		305	push @{$self->{join}}, $current;
		306	&schedule;
		307	}
		308	wantarray ? @{$self->{status}} : $self->{status}[0];
		309	}
		310
239	=item $oldprio = $process->prio($newprio)	311	=item $oldprio = $coroutine->prio ($newprio)
240		312
241	Sets the priority of the process. Higher priority processes get run before	313	Sets (or gets, if the argument is missing) the priority of the
242	lower priority processes. Priorities are smalled signed integer (currently	314	coroutine. Higher priority coroutines get run before lower priority
		315	coroutines. Priorities are small signed integers (currently -4 .. +3),
243	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import	316	that you can refer to using PRIO_xxx constants (use the import tag :prio
244	tag :prio to get then):	317	to get then):
245		318
246	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	319	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
247	3 > 1 > 0 > -1 > -3 > -4	320	3 > 1 > 0 > -1 > -3 > -4
248		321
249	# set priority to HIGH	322	# set priority to HIGH
250	current->prio(PRIO_HIGH);	323	current->prio(PRIO_HIGH);
251		324
252	The idle coroutine ($Coro::idle) always has a lower priority than any	325	The idle coroutine ($Coro::idle) always has a lower priority than any
253	existing coroutine.	326	existing coroutine.
254		327
255	Changing the priority of the current process will take effect immediately,	328	Changing the priority of the current coroutine will take effect immediately,
256	but changing the priority of processes in the ready queue (but not	329	but changing the priority of coroutines in the ready queue (but not
257	running) will only take effect after the next schedule (of that	330	running) will only take effect after the next schedule (of that
258	process). This is a bug that will be fixed in some future version.	331	coroutine). This is a bug that will be fixed in some future version.
259		332
260	=cut
261
262	sub prio {
263	my $old = $_[0]{prio};
264	$_[0]{prio} = $_[1] if @_ > 1;
265	$old;
266	}
267
268	=item $newprio = $process->nice($change)	333	=item $newprio = $coroutine->nice ($change)
269		334
270	Similar to C<prio>, but subtract the given value from the priority (i.e.	335	Similar to C<prio>, but subtract the given value from the priority (i.e.
271	higher values mean lower priority, just as in unix).	336	higher values mean lower priority, just as in unix).
272		337
273	=cut	338	=item $olddesc = $coroutine->desc ($newdesc)
274		339
275	sub nice {	340	Sets (or gets in case the argument is missing) the description for this
276	$_[0]{prio} -= $_[1];	341	coroutine. This is just a free-form string you can associate with a coroutine.
		342
		343	=cut
		344
		345	sub desc {
		346	my $old = $_[0]{desc};
		347	$_[0]{desc} = $_[1] if @_ > 1;
		348	$old;
277	}	349	}
278		350
279	=back	351	=back
280		352
		353	=head2 GLOBAL FUNCTIONS
		354
		355	=over 4
		356
		357	=item Coro::nready
		358
		359	Returns the number of coroutines that are currently in the ready state,
		360	i.e. that can be swicthed to. The value C<0> means that the only runnable
		361	coroutine is the currently running one, so C<cede> would have no effect,
		362	and C<schedule> would cause a deadlock unless there is an idle handler
		363	that wakes up some coroutines.
		364
		365	=item unblock_sub { ... }
		366
		367	This utility function takes a BLOCK or code reference and "unblocks" it,
		368	returning the new coderef. This means that the new coderef will return
		369	immediately without blocking, returning nothing, while the original code
		370	ref will be called (with parameters) from within its own coroutine.
		371
		372	The reason this fucntion exists is that many event libraries (such as the
		373	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		374	of thread-safety). This means you must not block within event callbacks,
		375	otherwise you might suffer from crashes or worse.
		376
		377	This function allows your callbacks to block by executing them in another
		378	coroutine where it is safe to block. One example where blocking is handy
		379	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		380	disk.
		381
		382	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		383	creating event callbacks that want to block.
		384
		385	=cut
		386
		387	our @unblock_pool;
		388	our @unblock_queue;
		389	our $UNBLOCK_POOL_SIZE = 2;
		390
		391	sub unblock_handler_ {
		392	while () {
		393	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		394	$cb->(@arg);
		395
		396	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		397	push @unblock_pool, $Coro::current;
		398	schedule;
		399	}
		400	}
		401
		402	our $unblock_scheduler = async {
		403	while () {
		404	while (my $cb = pop @unblock_queue) {
		405	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		406	$handler->{arg} = $cb;
		407	$handler->ready;
		408	cede;
		409	}
		410
		411	schedule;
		412	}
		413	};
		414
		415	sub unblock_sub(&) {
		416	my $cb = shift;
		417
		418	sub {
		419	push @unblock_queue, [$cb, @_];
		420	$unblock_scheduler->ready;
		421	}
		422	}
		423
		424	=back
		425
281	=cut	426	=cut
282		427
283	1;	428	1;
284		429
285	=head1 BUGS/LIMITATIONS	430	=head1 BUGS/LIMITATIONS
286		431
287	- you must make very sure that no coro is still active on global destruction.	432	- you must make very sure that no coro is still active on global
288	very bad things might happen otherwise (usually segfaults).	433	destruction. very bad things might happen otherwise (usually segfaults).
		434
289	- this module is not thread-safe. You must only ever use this module from	435	- this module is not thread-safe. You should only ever use this module
290	the same thread (this requirement might be loosened in the future to	436	from the same thread (this requirement might be losened in the future
291	allow per-thread schedulers, but Coro::State does not yet allow this).	437	to allow per-thread schedulers, but Coro::State does not yet allow
		438	this).
292		439
293	=head1 SEE ALSO	440	=head1 SEE ALSO
294		441
295	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	442	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
296	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,	443
297	L<Coro::Handle>, L<Coro::Socket>.	444	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		445
		446	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		447
		448	Embedding: L<Coro:MakeMaker>
298		449
299	=head1 AUTHOR	450	=head1 AUTHOR
300		451
301	Marc Lehmann <pcg@goof.com>	452	Marc Lehmann <schmorp@schmorp.de>
302	http://www.goof.com/pcg/marc/	453	http://home.schmorp.de/
303		454
304	=cut	455	=cut
305		456

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Comparing Coro/Coro.pm (file contents): Revision 1.36 by root, Mon Sep 24 01:36:20 2001 UTC vs. Revision 1.97 by root, Mon Dec 4 13:47:56 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.36 by root, Mon Sep 24 01:36:20 2001 UTC vs.
Revision 1.97 by root, Mon Dec 4 13:47:56 2006 UTC