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

Comparing Coro/Coro.pm (file contents):
Revision 1.29 by root, Sat Aug 11 00:37:31 2001 UTC vs.
Revision 1.95 by root, Sun Dec 3 22:50:06 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;
		36	no warnings "uninitialized";
		37
37	use Coro::State;	38	use Coro::State;
38		39
39	use base Exporter;	40	use base qw(Coro::State Exporter);
40		41
41	$VERSION = 0.45;	42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
42		45
		46	our $VERSION = '3.01';
		47
43	@EXPORT = qw(async cede schedule terminate current);	48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
44	@EXPORT_OK = qw($current);	49	our %EXPORT_TAGS = (
		50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		51	);
		52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
45		53
46	{	54	{
47	my @async;	55	my @async;
48	my $init;	56	my $init;
49		57
50	# this way of handling attributes simply is NOT scalable ;()	58	# this way of handling attributes simply is NOT scalable ;()
51	sub import {	59	sub import {
		60	no strict 'refs';
		61
52	Coro->export_to_level(1, @_);	62	Coro->export_to_level (1, @_);
		63
53	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
54	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
55	my ($package, $ref) = (shift, shift);	66	my ($package, $ref) = (shift, shift);
56	my @attrs;	67	my @attrs;
57	for (@_) {	68	for (@_) {
…		…
72	};	83	};
73	}	84	}
74		85
75	}	86	}
76		87
		88	=over 4
		89
77	=item $main	90	=item $main
78		91
79	This coroutine represents the main program.	92	This coroutine represents the main program.
80		93
81	=cut	94	=cut
82		95
83	our $main = new Coro;	96	$main = new Coro;
84		97
85	=item $current (or as function: current)	98	=item $current (or as function: current)
86		99
87	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$main> (of course).
		102
		103	This variable is B<strictly> I<read-only>. It is provided for performance
		104	reasons. If performance is not essentiel you are encouraged to use the
		105	C<Coro::current> function instead.
88		106
89	=cut	107	=cut
90		108
91	# maybe some other module used Coro::Specific before...	109	# maybe some other module used Coro::Specific before...
92	if ($current) {
93	$main->{specific} = $current->{specific};	110	$main->{specific} = $current->{specific}
94	}	111	if $current;
95		112
96	our $current = $main;	113	_set_current $main;
97		114
98	sub current() { $current }	115	sub current() { $current }
99		116
100	=item $idle	117	=item $idle
101		118
102	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
103	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.
104		122
105	=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.
106		126
107	# should be done using priorities :(	127	Please note that if your callback recursively invokes perl (e.g. for event
108	our $idle = new Coro sub {	128	handlers), then it must be prepared to be called recursively.
		129
		130	=cut
		131
		132	$idle = sub {
109	print STDERR "FATAL: deadlock detected\n";	133	print STDERR "FATAL: deadlock detected\n";
110	exit(51);	134	exit (51);
111	};	135	};
112		136
113	# this coroutine is necessary because a coroutine	137	# this coroutine is necessary because a coroutine
114	# cannot destroy itself.	138	# cannot destroy itself.
115	my @destroy;	139	my @destroy;
116	my $manager = new Coro sub {	140	my $manager; $manager = new Coro sub {
117	while() {	141	while () {
118	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	}
119	&schedule;	158	&schedule;
120	}	159	}
121	};	160	};
122		161
123	# we really need priorities...
124	my @ready; # the ready queue. hehe, rather broken ;)
125
126	# static methods. not really.	162	# static methods. not really.
127		163
		164	=back
		165
128	=head2 STATIC METHODS	166	=head2 STATIC METHODS
129		167
130	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.
131		169
132	=over 4	170	=over 4
133		171
134	=item async { ... } [@args...]	172	=item async { ... } [@args...]
135		173
136	Create a new asynchronous process and return it's process object	174	Create a new asynchronous coroutine and return it's coroutine object
137	(usually unused). When the sub returns the new process is automatically	175	(usually unused). When the sub returns the new coroutine is automatically
138	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.
139		182
140	# create a new coroutine that just prints its arguments	183	# create a new coroutine that just prints its arguments
141	async {	184	async {
142	print "@_\n";	185	print "@_\n";
143	} 1,2,3,4;	186	} 1,2,3,4;
144		187
145	The coderef you submit MUST NOT be a closure that refers to variables
146	in an outer scope. This does NOT work. Pass arguments into it instead.
147
148	=cut	188	=cut
149		189
150	sub async(&@) {	190	sub async(&@) {
151	my $pid = new Coro @_;	191	my $pid = new Coro @_;
152	$manager->ready; # this ensures that the stack is cloned from the manager
153	$pid->ready;	192	$pid->ready;
154	$pid;	193	$pid
155	}	194	}
156		195
157	=item schedule	196	=item schedule
158		197
159	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
160	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
161	never be called again.	200	never be called again unless something else (e.g. an event handler) calls
		201	ready.
162		202
163	=cut	203	The canonical way to wait on external events is this:
164		204
165	my $prev;	205	{
		206	# remember current coroutine
		207	my $current = $Coro::current;
166		208
167	sub schedule {	209	# register a hypothetical event handler
168	# should be done using priorities :(	210	on_event_invoke sub {
169	($prev, $current) = ($current, shift @ready \|\| $idle);	211	# wake up sleeping coroutine
170	Coro::State::transfer($prev, $current);	212	$current->ready;
171	}	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	}
172		221
173	=item cede	222	=item cede
174		223
175	"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
176	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
177	current "timeslice" to other coroutines of the same or higher priority.	226	current "timeslice" to other coroutines of the same or higher priority.
178		227
179	=cut
180
181	sub cede {
182	$current->ready;
183	&schedule;
184	}
185
186	=item terminate	228	=item terminate [arg...]
187		229
188	Terminates the current process.	230	Terminates the current coroutine with the given status values (see L<cancel>).
189
190	Future versions of this function will allow result arguments.
191		231
192	=cut	232	=cut
193		233
194	sub terminate {	234	sub terminate {
195	$current->cancel;	235	$current->cancel (@_);
196	&schedule;
197	die; # NORETURN
198	}	236	}
199		237
200	=back	238	=back
201		239
202	# dynamic methods	240	# dynamic methods
203		241
204	=head2 PROCESS METHODS	242	=head2 COROUTINE METHODS
205		243
206	These are the methods you can call on process objects.	244	These are the methods you can call on coroutine objects.
207		245
208	=over 4	246	=over 4
209		247
210	=item new Coro \&sub [, @args...]	248	=item new Coro \&sub [, @args...]
211		249
212	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
213	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
214	the ready queue by calling the ready method.	253	by calling the ready method.
215		254
216	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.
217	in an outer scope. This does NOT work. Pass arguments into it instead.
218		256
219	=cut	257	=cut
220		258
221	sub _newcoro {	259	sub _run_coro {
222	terminate &{+shift};	260	terminate &{+shift};
223	}	261	}
224		262
225	sub new {	263	sub new {
226	my $class = shift;	264	my $class = shift;
227	bless {
228	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
229	}, $class;
230	}
231		265
232	=item $process->ready	266	$class->SUPER::new (\&_run_coro, @_)
233
234	Put the current process into the ready queue.
235
236	=cut
237
238	sub ready {
239	push @ready, $_[0];
240	}	267	}
241		268
242	=item $process->cancel	269	=item $success = $coroutine->ready
243		270
244	Like C<terminate>, but terminates the specified process instead.	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.
		274
		275	=item $is_ready = $coroutine->is_ready
		276
		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).
245		283
246	=cut	284	=cut
247		285
248	sub cancel {	286	sub cancel {
		287	my $self = shift;
		288	$self->{status} = [@_];
249	push @destroy, $_[0];	289	push @destroy, $self;
250	$manager->ready;	290	$manager->ready;
		291	&schedule if $current == $self;
		292	}
		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
		311	=item $oldprio = $coroutine->prio ($newprio)
		312
		313	Sets (or gets, if the argument is missing) the priority of the
		314	coroutine. Higher priority coroutines get run before lower priority
		315	coroutines. Priorities are small signed integers (currently -4 .. +3),
		316	that you can refer to using PRIO_xxx constants (use the import tag :prio
		317	to get then):
		318
		319	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		320	3 > 1 > 0 > -1 > -3 > -4
		321
		322	# set priority to HIGH
		323	current->prio(PRIO_HIGH);
		324
		325	The idle coroutine ($Coro::idle) always has a lower priority than any
		326	existing coroutine.
		327
		328	Changing the priority of the current coroutine will take effect immediately,
		329	but changing the priority of coroutines in the ready queue (but not
		330	running) will only take effect after the next schedule (of that
		331	coroutine). This is a bug that will be fixed in some future version.
		332
		333	=item $newprio = $coroutine->nice ($change)
		334
		335	Similar to C<prio>, but subtract the given value from the priority (i.e.
		336	higher values mean lower priority, just as in unix).
		337
		338	=item $olddesc = $coroutine->desc ($newdesc)
		339
		340	Sets (or gets in case the argument is missing) the description for this
		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;
251	}	349	}
252		350
253	=back	351	=back
254		352
		353	=head2 UTILITY FUNCTIONS
		354
		355	=over 4
		356
		357	=item unblock_sub { ... }
		358
		359	This utility function takes a BLOCK or code reference and "unblocks" it,
		360	returning the new coderef. This means that the new coderef will return
		361	immediately without blocking, returning nothing, while the original code
		362	ref will be called (with parameters) from within its own coroutine.
		363
		364	The reason this fucntion exists is that many event libraries (such as the
		365	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		366	of thread-safety). This means you must not block within event callbacks,
		367	otherwise you might suffer from crashes or worse.
		368
		369	This function allows your callbacks to block by executing them in another
		370	coroutine where it is safe to block. One example where blocking is handy
		371	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		372	disk.
		373
		374	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		375	creating event callbacks that want to block.
		376
		377	=cut
		378
		379	our @unblock_pool;
		380	our @unblock_queue;
		381	our $UNBLOCK_POOL_SIZE = 2;
		382
		383	sub unblock_handler_ {
		384	while () {
		385	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		386	$cb->(@arg);
		387
		388	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		389	push @unblock_pool, $Coro::current;
		390	schedule;
		391	}
		392	}
		393
		394	our $unblock_scheduler = async {
		395	while () {
		396	while (my $cb = pop @unblock_queue) {
		397	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		398	$handler->{arg} = $cb;
		399	$handler->ready;
		400	cede;
		401	}
		402
		403	schedule;
		404	}
		405	};
		406
		407	sub unblock_sub(&) {
		408	my $cb = shift;
		409
		410	sub {
		411	push @unblock_queue, [$cb, @_];
		412	$unblock_scheduler->ready;
		413	}
		414	}
		415
		416	=back
		417
255	=cut	418	=cut
256		419
257	1;	420	1;
258		421
259	=head1 BUGS/LIMITATIONS	422	=head1 BUGS/LIMITATIONS
260		423
261	- could be faster, especially when the core would introduce special	424	- you must make very sure that no coro is still active on global
262	support for coroutines (like it does for threads).	425	destruction. very bad things might happen otherwise (usually segfaults).
263	- there is still a memleak on coroutine termination that I could not	426
264	identify. Could be as small as a single SV.
265	- this module is not well-tested.
266	- if variables or arguments "disappear" (become undef) or become
267	corrupted please contact the author so he cen iron out the
268	remaining bugs.
269	- this module is not thread-safe. You must only ever use this module from	427	- this module is not thread-safe. You should only ever use this module
270	the same thread (this requirement might be loosened in the future to	428	from the same thread (this requirement might be losened in the future
271	allow per-thread schedulers, but Coro::State does not yet allow this).	429	to allow per-thread schedulers, but Coro::State does not yet allow
		430	this).
272		431
273	=head1 SEE ALSO	432	=head1 SEE ALSO
274		433
275	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	434	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
276	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,	435
277	L<Coro::Handle>, L<Coro::Socket>.	436	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		437
		438	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		439
		440	Embedding: L<Coro:MakeMaker>
278		441
279	=head1 AUTHOR	442	=head1 AUTHOR
280		443
281	Marc Lehmann <pcg@goof.com>	444	Marc Lehmann <schmorp@schmorp.de>
282	http://www.goof.com/pcg/marc/	445	http://home.schmorp.de/
283		446
284	=cut	447	=cut
285		448

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Comparing Coro/Coro.pm (file contents): Revision 1.29 by root, Sat Aug 11 00:37:31 2001 UTC vs. Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.29 by root, Sat Aug 11 00:37:31 2001 UTC vs.
Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC