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

Comparing Coro/Coro.pm (file contents):
Revision 1.24 by root, Wed Jul 25 04:14:37 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 = 0.12;	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;
		56	my $init;
48		57
49	# this way of handling attributes simply is NOT scalable ;()	58	# this way of handling attributes simply is NOT scalable ;()
50	sub import {	59	sub import {
		60	no strict 'refs';
		61
51	Coro->export_to_level(1, @_);	62	Coro->export_to_level (1, @_);
		63
52	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
53	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
54	my ($package, $ref) = (shift, shift);	66	my ($package, $ref) = (shift, shift);
55	my @attrs;	67	my @attrs;
56	for (@_) {	68	for (@_) {
57	if ($_ eq "Coro") {	69	if ($_ eq "Coro") {
58	push @async, $ref;	70	push @async, $ref;
		71	unless ($init++) {
		72	eval q{
		73	sub INIT {
		74	&async(pop @async) while @async;
		75	}
		76	};
		77	}
59	} else {	78	} else {
60	push @attrs, $_;	79	push @attrs, $_;
61	}	80	}
62	}	81	}
63	return $old ? $old->($package, $ref, @attrs) : @attrs;	82	return $old ? $old->($package, $ref, @attrs) : @attrs;
64	};	83	};
65	}	84	}
66		85
67	sub INIT {
68	&async(pop @async) while @async;
69	}
70	}	86	}
		87
		88	=over 4
71		89
72	=item $main	90	=item $main
73		91
74	This coroutine represents the main program.	92	This coroutine represents the main program.
75		93
76	=cut	94	=cut
77		95
78	our $main = new Coro;	96	$main = new Coro;
79		97
80	=item $current (or as function: current)	98	=item $current (or as function: current)
81		99
82	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$main> (of course).
		102
		103	This variable is B<strictly> I<read-only>. It is provided for performance
		104	reasons. If performance is not essentiel you are encouraged to use the
		105	C<Coro::current> function instead.
83		106
84	=cut	107	=cut
85		108
86	# maybe some other module used Coro::Specific before...	109	# maybe some other module used Coro::Specific before...
87	if ($current) {
88	$main->{specific} = $current->{specific};	110	$main->{specific} = $current->{specific}
89	}	111	if $current;
90		112
91	our $current = $main;	113	_set_current $main;
92		114
93	sub current() { $current }	115	sub current() { $current }
94		116
95	=item $idle	117	=item $idle
96		118
97	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
98	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.
99		122
100	=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.
101		126
102	# should be done using priorities :(	127	Please note that if your callback recursively invokes perl (e.g. for event
103	our $idle = new Coro sub {	128	handlers), then it must be prepared to be called recursively.
		129
		130	=cut
		131
		132	$idle = sub {
104	print STDERR "FATAL: deadlock detected\n";	133	print STDERR "FATAL: deadlock detected\n";
105	exit(51);	134	exit (51);
106	};	135	};
107		136
108	# this coroutine is necessary because a coroutine	137	# this coroutine is necessary because a coroutine
109	# cannot destroy itself.	138	# cannot destroy itself.
110	my @destroy;	139	my @destroy;
111	my $manager = new Coro sub {	140	my $manager; $manager = new Coro sub {
112	while() {	141	while () {
113	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	}
114	&schedule;	158	&schedule;
115	}	159	}
116	};	160	};
117		161
118	# we really need priorities...
119	my @ready; # the ready queue. hehe, rather broken ;)
120
121	# static methods. not really.	162	# static methods. not really.
122		163
		164	=back
		165
123	=head2 STATIC METHODS	166	=head2 STATIC METHODS
124		167
125	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.
126		169
127	=over 4	170	=over 4
128		171
129	=item async { ... } [@args...]	172	=item async { ... } [@args...]
130		173
131	Create a new asynchronous process and return it's process object	174	Create a new asynchronous coroutine and return it's coroutine object
132	(usually unused). When the sub returns the new process is automatically	175	(usually unused). When the sub returns the new coroutine is automatically
133	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.
134		182
135	# create a new coroutine that just prints its arguments	183	# create a new coroutine that just prints its arguments
136	async {	184	async {
137	print "@_\n";	185	print "@_\n";
138	} 1,2,3,4;	186	} 1,2,3,4;
139		187
140	The coderef you submit MUST NOT be a closure that refers to variables
141	in an outer scope. This does NOT work. Pass arguments into it instead.
142
143	=cut	188	=cut
144		189
145	sub async(&@) {	190	sub async(&@) {
146	my $pid = new Coro @_;	191	my $pid = new Coro @_;
147	$manager->ready; # this ensures that the stack is cloned from the manager
148	$pid->ready;	192	$pid->ready;
149	$pid;	193	$pid
150	}	194	}
151		195
152	=item schedule	196	=item schedule
153		197
154	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
155	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
156	never be called again.	200	never be called again unless something else (e.g. an event handler) calls
		201	ready.
157		202
158	=cut	203	The canonical way to wait on external events is this:
159		204
160	my $prev;	205	{
		206	# remember current coroutine
		207	my $current = $Coro::current;
161		208
162	sub schedule {	209	# register a hypothetical event handler
163	# should be done using priorities :(	210	on_event_invoke sub {
164	($prev, $current) = ($current, shift @ready \|\| $idle);	211	# wake up sleeping coroutine
165	Coro::State::transfer($prev, $current);	212	$current->ready;
166	}	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	}
167		221
168	=item cede	222	=item cede
169		223
170	"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
171	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
172	current "timeslice" to other coroutines of the same or higher priority.	226	current "timeslice" to other coroutines of the same or higher priority.
173		227
174	=cut
175
176	sub cede {
177	$current->ready;
178	&schedule;
179	}
180
181	=item terminate	228	=item terminate [arg...]
182		229
183	Terminates the current process.	230	Terminates the current coroutine with the given status values (see L<cancel>).
184
185	Future versions of this function will allow result arguments.
186		231
187	=cut	232	=cut
188		233
189	sub terminate {	234	sub terminate {
190	push @destroy, $current;	235	$current->cancel (@_);
191	$manager->ready;
192	&schedule;
193	# NORETURN
194	}	236	}
195		237
196	=back	238	=back
197		239
198	# dynamic methods	240	# dynamic methods
199		241
200	=head2 PROCESS METHODS	242	=head2 COROUTINE METHODS
201		243
202	These are the methods you can call on process objects.	244	These are the methods you can call on coroutine objects.
203		245
204	=over 4	246	=over 4
205		247
206	=item new Coro \&sub [, @args...]	248	=item new Coro \&sub [, @args...]
207		249
208	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
209	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
210	the ready queue by calling the ready method.	253	by calling the ready method.
211		254
212	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.
213	in an outer scope. This does NOT work. Pass arguments into it instead.
214		256
215	=cut	257	=cut
216		258
217	sub _newcoro {	259	sub _run_coro {
218	terminate &{+shift};	260	terminate &{+shift};
219	}	261	}
220		262
221	sub new {	263	sub new {
222	my $class = shift;	264	my $class = shift;
223	bless {
224	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
225	}, $class;
226	}
227		265
228	=item $process->ready	266	$class->SUPER::new (\&_run_coro, @_)
		267	}
229		268
230	Put the current process into the ready queue.	269	=item $success = $coroutine->ready
231		270
232	=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.
233		274
234	sub ready {	275	=item $is_ready = $coroutine->is_ready
235	push @ready, $_[0];	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).
		283
		284	=cut
		285
		286	sub cancel {
		287	my $self = shift;
		288	$self->{status} = [@_];
		289	push @destroy, $self;
		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;
236	}	349	}
237		350
238	=back	351	=back
239		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
240	=cut	418	=cut
241		419
242	1;	420	1;
243		421
244	=head1 BUGS/LIMITATIONS	422	=head1 BUGS/LIMITATIONS
245		423
246	- could be faster, especially when the core would introduce special	424	- you must make very sure that no coro is still active on global
247	support for coroutines (like it does for threads).	425	destruction. very bad things might happen otherwise (usually segfaults).
248	- there is still a memleak on coroutine termination that I could not	426
249	identify. Could be as small as a single SV.
250	- this module is not well-tested.
251	- if variables or arguments "disappear" (become undef) or become
252	corrupted please contact the author so he cen iron out the
253	remaining bugs.
254	- 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
255	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
256	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).
257		431
258	=head1 SEE ALSO	432	=head1 SEE ALSO
259		433
260	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>.
261	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.	435
		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>
262		441
263	=head1 AUTHOR	442	=head1 AUTHOR
264		443
265	Marc Lehmann <pcg@goof.com>	444	Marc Lehmann <schmorp@schmorp.de>
266	http://www.goof.com/pcg/marc/	445	http://home.schmorp.de/
267		446
268	=cut	447	=cut
269		448

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Comparing Coro/Coro.pm (file contents): Revision 1.24 by root, Wed Jul 25 04:14:37 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 1.24 by root, Wed Jul 25 04:14:37 2001 UTC vs.
Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC