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

Comparing Coro/Coro.pm (file contents):
Revision 1.8 by root, Sat Jul 14 22:14:21 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	yield;	19	cede;
20		20
21	=head1 DESCRIPTION	21	=head1 DESCRIPTION
22		22
		23	This module collection manages coroutines. Coroutines are similar to
		24	threads but don't run in parallel.
		25
		26	In this module, coroutines are defined as "callchain + lexical variables
		27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
		28	callchain, it's own set of lexicals and it's own set of perl's most
		29	important global variables.
		30
23	=cut	31	=cut
24		32
25	package Coro;	33	package Coro;
26		34
		35	use strict;
		36	no warnings "uninitialized";
		37
27	use Coro::State;	38	use Coro::State;
28		39
29	use base Exporter;	40	use base qw(Coro::State Exporter);
30		41
31	$VERSION = 0.03;	42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
32		45
33	@EXPORT = qw(async yield schedule);	46	our $VERSION = '3.01';
34	@EXPORT_OK = qw($current);	47
		48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
		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}};
35		53
36	{	54	{
37	use subs 'async';
38
39	my @async;	55	my @async;
		56	my $init;
40		57
41	# this way of handling attributes simply is NOT scalable ;()	58	# this way of handling attributes simply is NOT scalable ;()
42	sub import {	59	sub import {
		60	no strict 'refs';
		61
43	Coro->export_to_level(1, @_);	62	Coro->export_to_level (1, @_);
		63
44	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
45	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
46	my ($package, $ref) = (shift, shift);	66	my ($package, $ref) = (shift, shift);
47	my @attrs;	67	my @attrs;
48	for (@_) {	68	for (@_) {
49	if ($_ eq "Coro") {	69	if ($_ eq "Coro") {
50	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	}
51	} else {	78	} else {
52	push @attrs, @_;	79	push @attrs, $_;
53	}	80	}
54	}	81	}
55	return $old ? $old->($package, $name, @attrs) : @attrs;	82	return $old ? $old->($package, $ref, @attrs) : @attrs;
56	};	83	};
57	}	84	}
58		85
59	sub INIT {
60	async pop @async while @async;
61	}
62	}	86	}
63		87
64	my $idle = new Coro sub {	88	=over 4
65	&yield while 1;	89
		90	=item $main
		91
		92	This coroutine represents the main program.
		93
		94	=cut
		95
		96	$main = new Coro;
		97
		98	=item $current (or as function: current)
		99
		100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$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.
		106
		107	=cut
		108
		109	# maybe some other module used Coro::Specific before...
		110	$main->{specific} = $current->{specific}
		111	if $current;
		112
		113	_set_current $main;
		114
		115	sub current() { $current }
		116
		117	=item $idle
		118
		119	A callback that is called whenever the scheduler finds no ready coroutines
		120	to run. The default implementation prints "FATAL: deadlock detected" and
		121	exits, because the program has no other way to continue.
		122
		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.
		126
		127	Please note that if your callback recursively invokes perl (e.g. for event
		128	handlers), then it must be prepared to be called recursively.
		129
		130	=cut
		131
		132	$idle = sub {
		133	print STDERR "FATAL: deadlock detected\n";
		134	exit (51);
66	};	135	};
67		136
68	=item $main	137	# this coroutine is necessary because a coroutine
		138	# cannot destroy itself.
		139	my @destroy;
		140	my $manager; $manager = new Coro sub {
		141	while () {
		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} \|\| []};
69		151
70	This coroutine represents the main program.	152	# the next line destroys the coro state, but keeps the
71		153	# coroutine itself intact (we basically make it a zombie
72	=cut	154	# coroutine that always runs the manager thread, so it's possible
73		155	# to transfer() to this coroutine).
74	$main = new Coro;	156	$coro->_clone_state_from ($manager);
75		157	}
76	=item $current	158	&schedule;
77		159	}
78	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	160	};
79
80	=cut
81
82	# maybe some other module used Coro::Specific before...
83	if ($current) {
84	$main->{specific} = $current->{specific};
85	}
86
87	$current = $main;
88
89	# we really need priorities...
90	my @ready = (); # the ready queue. hehe, rather broken ;)
91		161
92	# static methods. not really.	162	# static methods. not really.
93		163
		164	=back
		165
94	=head2 STATIC METHODS	166	=head2 STATIC METHODS
95		167
96	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.
97		169
98	=over 4	170	=over 4
99		171
100	=item async { ... };	172	=item async { ... } [@args...]
101		173
102	Create a new asynchronous process and return it's process object	174	Create a new asynchronous coroutine and return it's coroutine object
103	(usually unused). When the sub returns the new process is automatically	175	(usually unused). When the sub returns the new coroutine is automatically
104	terminated.	176	terminated.
105		177
106	=cut	178	Calling C<exit> in a coroutine will not work correctly, so do not do that.
107		179
		180	When the coroutine dies, the program will exit, just as in the main
		181	program.
		182
		183	# create a new coroutine that just prints its arguments
		184	async {
		185	print "@_\n";
		186	} 1,2,3,4;
		187
		188	=cut
		189
108	sub async(&) {	190	sub async(&@) {
109	(new Coro $_[0])->ready;	191	my $pid = new Coro @_;
		192	$pid->ready;
		193	$pid
110	}	194	}
111		195
112	=item schedule	196	=item schedule
113		197
114	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
115	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
116	never be called again.	200	never be called again unless something else (e.g. an event handler) calls
		201	ready.
117		202
118	=cut	203	The canonical way to wait on external events is this:
119		204
120	my $prev;	205	{
		206	# remember current coroutine
		207	my $current = $Coro::current;
121		208
122	sub schedule {	209	# register a hypothetical event handler
123	($prev, $current) = ($current, shift @ready);	210	on_event_invoke sub {
124	Coro::State::transfer($prev, $current);	211	# wake up sleeping coroutine
125	}
126
127	=item yield
128
129	Yield to other processes. This function puts the current process into the
130	ready queue and calls C<schedule>.
131
132	=cut
133
134	sub yield {
135	$current->ready;	212	$current->ready;
136	&schedule;	213	undef $current;
137	}	214	};
138		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	}
		221
		222	=item cede
		223
		224	"Cede" to other coroutines. This function puts the current coroutine into the
		225	ready queue and calls C<schedule>, which has the effect of giving up the
		226	current "timeslice" to other coroutines of the same or higher priority.
		227
139	=item terminate	228	=item terminate [arg...]
140		229
141	Terminates the current process.	230	Terminates the current coroutine with the given status values (see L<cancel>).
142		231
143	=cut	232	=cut
144		233
145	sub terminate {	234	sub terminate {
146	&schedule;	235	$current->cancel (@_);
147	}	236	}
148		237
149	=back	238	=back
150		239
151	# dynamic methods	240	# dynamic methods
152		241
153	=head2 PROCESS METHODS	242	=head2 COROUTINE METHODS
154		243
155	These are the methods you can call on process objects.	244	These are the methods you can call on coroutine objects.
156		245
157	=over 4	246	=over 4
158		247
159	=item new Coro \⊂	248	=item new Coro \&sub [, @args...]
160		249
161	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
162	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
163	the ready queue by calling the ready method.	253	by calling the ready method.
164		254
		255	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		256
165	=cut	257	=cut
		258
		259	sub _run_coro {
		260	terminate &{+shift};
		261	}
166		262
167	sub new {	263	sub new {
168	my $class = shift;	264	my $class = shift;
		265
		266	$class->SUPER::new (\&_run_coro, @_)
		267	}
		268
		269	=item $success = $coroutine->ready
		270
		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).
		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 {
169	my $proc = $_[0];	346	my $old = $_[0]{desc};
170	bless {	347	$_[0]{desc} = $_[1] if @_ > 1;
171	_coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc),	348	$old;
172	}, $class;
173	}
174
175	=item $process->ready
176
177	Put the current process into the ready queue.
178
179	=cut
180
181	sub ready {
182	push @ready, $_[0];
183	}	349	}
184		350
185	=back	351	=back
186		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
187	=cut	418	=cut
188		419
189	1;	420	1;
190		421
		422	=head1 BUGS/LIMITATIONS
		423
		424	- you must make very sure that no coro is still active on global
		425	destruction. very bad things might happen otherwise (usually segfaults).
		426
		427	- this module is not thread-safe. You should only ever use this module
		428	from the same thread (this requirement might be losened in the future
		429	to allow per-thread schedulers, but Coro::State does not yet allow
		430	this).
		431
		432	=head1 SEE ALSO
		433
		434	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
		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>
		441
191	=head1 AUTHOR	442	=head1 AUTHOR
192		443
193	Marc Lehmann <pcg@goof.com>	444	Marc Lehmann <schmorp@schmorp.de>
194	http://www.goof.com/pcg/marc/	445	http://home.schmorp.de/
195		446
196	=cut	447	=cut
197		448

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Comparing Coro/Coro.pm (file contents): Revision 1.8 by root, Sat Jul 14 22:14:21 2001 UTC vs. Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.8 by root, Sat Jul 14 22:14:21 2001 UTC vs.
Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC