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

Comparing Coro/Coro.pm (file contents):
Revision 1.12 by root, Sun Jul 15 15:58:16 2001 UTC vs.
Revision 1.93 by root, Fri Dec 1 19:41:06 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
		42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
		45
31	$VERSION = 0.05;	46	our $VERSION = '3.0';
32		47
33	@EXPORT = qw(async yield schedule);	48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
34	@EXPORT_OK = qw($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}};
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	}
		87
		88	=over 4
63		89
64	=item $main	90	=item $main
65		91
66	This coroutine represents the main program.	92	This coroutine represents the main program.
67		93
68	=cut	94	=cut
69		95
70	our $main = new Coro;	96	$main = new Coro;
71		97
72	=item $current	98	=item $current (or as function: current)
73		99
74	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$main> (of course).
		102
		103	This variable is B<strictly> I<read-only>. It is provided for performance
		104	reasons. If performance is not essentiel you are encouraged to use the
		105	C<Coro::current> function instead.
75		106
76	=cut	107	=cut
77		108
78	# maybe some other module used Coro::Specific before...	109	# maybe some other module used Coro::Specific before...
79	if ($current) {
80	$main->{specific} = $current->{specific};	110	$main->{specific} = $current->{specific}
81	}	111	if $current;
82		112
83	our $current = $main;	113	_set_current $main;
		114
		115	sub current() { $current }
84		116
85	=item $idle	117	=item $idle
86		118
87	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
88	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.
89		122
90	=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.
91		126
92	# should be done using priorities :(	127	Please note that if your callback recursively invokes perl (e.g. for event
93	our $idle = new Coro sub {	128	handlers), then it must be prepared to be called recursively.
		129
		130	=cut
		131
		132	$idle = sub {
94	print STDERR "FATAL: deadlock detected\n";	133	print STDERR "FATAL: deadlock detected\n";
95	exit(51);	134	exit (51);
96	};	135	};
97		136
98	# we really need priorities...	137	# this coroutine is necessary because a coroutine
99	my @ready = (); # the ready queue. hehe, rather broken ;)	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} \|\| []};
		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	}
		158	&schedule;
		159	}
		160	};
100		161
101	# static methods. not really.	162	# static methods. not really.
102		163
		164	=back
		165
103	=head2 STATIC METHODS	166	=head2 STATIC METHODS
104		167
105	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.
106		169
107	=over 4	170	=over 4
108		171
109	=item async { ... };	172	=item async { ... } [@args...]
110		173
111	Create a new asynchronous process and return it's process object	174	Create a new asynchronous coroutine and return it's coroutine object
112	(usually unused). When the sub returns the new process is automatically	175	(usually unused). When the sub returns the new coroutine is automatically
113	terminated.	176	terminated.
114		177
115	=cut	178	Calling C<exit> in a coroutine will not work correctly, so do not do that.
116		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
117	sub async(&) {	190	sub async(&@) {
118	my $pid = new Coro $_[0];	191	my $pid = new Coro @_;
119	$pid->ready;	192	$pid->ready;
120	$pid;	193	$pid
121	}	194	}
122		195
123	=item schedule	196	=item schedule
124		197
125	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
126	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
127	never be called again.	200	never be called again unless something else (e.g. an event handler) calls
		201	ready.
128		202
129	=cut	203	The canonical way to wait on external events is this:
130		204
131	my $prev;	205	{
		206	# remember current coroutine
		207	my $current = $Coro::current;
132		208
133	sub schedule {	209	# register a hypothetical event handler
134	local @_;	210	on_event_invoke sub {
135	# should be done using priorities :(	211	# wake up sleeping coroutine
136	($prev, $current) = ($current, shift @ready \|\| $idle);
137	Coro::State::transfer($prev, $current);
138	}
139
140	=item yield
141
142	Yield to other processes. This function puts the current process into the
143	ready queue and calls C<schedule>.
144
145	=cut
146
147	sub yield {
148	$current->ready;	212	$current->ready;
149	&schedule;	213	undef $current;
150	}	214	};
151		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
152	=item terminate	228	=item terminate [arg...]
153		229
154	Terminates the current process.	230	Terminates the current coroutine with the given status values (see L<cancel>).
155		231
156	=cut	232	=cut
157		233
158	sub terminate {	234	sub terminate {
159	&schedule;	235	$current->cancel (@_);
160	}	236	}
161		237
162	=back	238	=back
163		239
164	# dynamic methods	240	# dynamic methods
165		241
166	=head2 PROCESS METHODS	242	=head2 COROUTINE METHODS
167		243
168	These are the methods you can call on process objects.	244	These are the methods you can call on coroutine objects.
169		245
170	=over 4	246	=over 4
171		247
172	=item new Coro \⊂	248	=item new Coro \&sub [, @args...]
173		249
174	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
175	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
176	the ready queue by calling the ready method.	253	by calling the ready method.
177		254
		255	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		256
178	=cut	257	=cut
		258
		259	sub _new_coro {
		260	terminate &{+shift};
		261	}
179		262
180	sub new {	263	sub new {
181	my $class = shift;	264	my $class = shift;
		265
		266	$class->SUPER::new (\&_new_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 {
182	my $proc = $_[0];	346	my $old = $_[0]{desc};
183	bless {	347	$_[0]{desc} = $_[1] if @_ > 1;
184	_coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc),	348	$old;
185	}, $class;
186	}
187
188	=item $process->ready
189
190	Put the current process into the ready queue.
191
192	=cut
193
194	sub ready {
195	push @ready, $_[0];
196	}	349	}
197		350
198	=back	351	=back
199		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
200	=cut	418	=cut
201		419
202	1;	420	1;
203		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
204	=head1 SEE ALSO	432	=head1 SEE ALSO
205		433
206	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>.
207	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>
208		441
209	=head1 AUTHOR	442	=head1 AUTHOR
210		443
211	Marc Lehmann <pcg@goof.com>	444	Marc Lehmann <schmorp@schmorp.de>
212	http://www.goof.com/pcg/marc/	445	http://home.schmorp.de/
213		446
214	=cut	447	=cut
215		448

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Comparing Coro/Coro.pm (file contents): Revision 1.12 by root, Sun Jul 15 15:58:16 2001 UTC vs. Revision 1.93 by root, Fri Dec 1 19:41:06 2006 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.12 by root, Sun Jul 15 15:58:16 2001 UTC vs.
Revision 1.93 by root, Fri Dec 1 19:41:06 2006 UTC