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

Comparing Coro/Coro.pm (file contents):
Revision 1.13 by root, Tue Jul 17 00:24:14 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	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 = 0.05;	42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
32		45
33	@EXPORT = qw(async yield schedule terminate);	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}}, qw(nready));
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.
94	print STDERR "FATAL: deadlock detected\n";	129
95	exit(51);	130	=cut
		131
		132	$idle = sub {
		133	require Carp;
		134	Carp::croak ("FATAL: deadlock detected");
96	};	135	};
97		136
98	# we really need priorities...	137	# this coroutine is necessary because a coroutine
99	## my @ready; #d#	138	# cannot destroy itself.
100	our @ready = (); # the ready queue. hehe, rather broken ;)	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	};
101		161
102	# static methods. not really.	162	# static methods. not really.
103		163
		164	=back
		165
104	=head2 STATIC METHODS	166	=head2 STATIC METHODS
105		167
106	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.
107		169
108	=over 4	170	=over 4
109		171
110	=item async { ... } [@args...]	172	=item async { ... } [@args...]
111		173
112	Create a new asynchronous process and return it's process object	174	Create a new asynchronous coroutine and return it's coroutine object
113	(usually unused). When the sub returns the new process is automatically	175	(usually unused). When the sub returns the new coroutine is automatically
114	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.
115		182
116	# create a new coroutine that just prints its arguments	183	# create a new coroutine that just prints its arguments
117	async {	184	async {
118	print "@_\n";	185	print "@_\n";
119	} 1,2,3,4;	186	} 1,2,3,4;
120		187
121	The coderef you submit MUST NOT be a closure that refers to variables
122	in an outer scope. This does NOT work. Pass arguments into it instead.
123
124	=cut	188	=cut
125		189
126	sub async(&@) {	190	sub async(&@) {
127	my $pid = new Coro @_;	191	my $pid = new Coro @_;
128	$pid->ready;	192	$pid->ready;
129	$pid;	193	$pid
130	}	194	}
131		195
132	=item schedule	196	=item schedule
133		197
134	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
135	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
136	never be called again.	200	never be called again unless something else (e.g. an event handler) calls
		201	ready.
137		202
138	=cut	203	The canonical way to wait on external events is this:
139		204
140	my $prev;	205	{
		206	# remember current coroutine
		207	my $current = $Coro::current;
141		208
142	sub schedule {	209	# register a hypothetical event handler
143	# should be done using priorities :(	210	on_event_invoke sub {
144	($prev, $current) = ($current, shift @ready \|\| $idle);	211	# wake up sleeping coroutine
145	Coro::State::transfer($prev, $current);
146	}
147
148	=item yield
149
150	Yield to other processes. This function puts the current process into the
151	ready queue and calls C<schedule>.
152
153	=cut
154
155	sub yield {
156	$current->ready;	212	$current->ready;
157	&schedule;	213	undef $current;
158	}	214	};
159		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
160	=item terminate	228	=item terminate [arg...]
161		229
162	Terminates the current process.	230	Terminates the current coroutine with the given status values (see L<cancel>).
163
164	Future versions of this function will allow result arguments.
165		231
166	=cut	232	=cut
167		233
168	sub terminate {	234	sub terminate {
169	$current->{_results} = [@_];	235	$current->cancel (@_);
170	&schedule;
171	}	236	}
172		237
173	=back	238	=back
174		239
175	# dynamic methods	240	# dynamic methods
176		241
177	=head2 PROCESS METHODS	242	=head2 COROUTINE METHODS
178		243
179	These are the methods you can call on process objects.	244	These are the methods you can call on coroutine objects.
180		245
181	=over 4	246	=over 4
182		247
183	=item new Coro \&sub [, @args...]	248	=item new Coro \&sub [, @args...]
184		249
185	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
186	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
187	the ready queue by calling the ready method.	253	by calling the ready method.
188		254
189	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.
190	in an outer scope. This does NOT work. Pass arguments into it instead.
191		256
192	=cut	257	=cut
193		258
194	sub _newcoro {	259	sub _run_coro {
195	terminate &{+shift};	260	terminate &{+shift};
196	}	261	}
197		262
198	sub new {	263	sub new {
199	my $class = shift;	264	my $class = shift;
200	bless {
201	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
202	}, $class;
203	}
204		265
205	=item $process->ready	266	$class->SUPER::new (\&_run_coro, @_)
		267	}
206		268
207	Put the current process into the ready queue.	269	=item $success = $coroutine->ready
208		270
209	=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.
210		274
211	sub ready {	275	=item $is_ready = $coroutine->is_ready
212	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;
213	}	349	}
214		350
215	=back	351	=back
216		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
217	=cut	426	=cut
218		427
219	1;	428	1;
220		429
		430	=head1 BUGS/LIMITATIONS
		431
		432	- you must make very sure that no coro is still active on global
		433	destruction. very bad things might happen otherwise (usually segfaults).
		434
		435	- this module is not thread-safe. You should only ever use this module
		436	from the same thread (this requirement might be losened in the future
		437	to allow per-thread schedulers, but Coro::State does not yet allow
		438	this).
		439
221	=head1 SEE ALSO	440	=head1 SEE ALSO
222		441
223	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>.
224	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.	443
		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>
225		449
226	=head1 AUTHOR	450	=head1 AUTHOR
227		451
228	Marc Lehmann <pcg@goof.com>	452	Marc Lehmann <schmorp@schmorp.de>
229	http://www.goof.com/pcg/marc/	453	http://home.schmorp.de/
230		454
231	=cut	455	=cut
232		456

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Comparing Coro/Coro.pm (file contents): Revision 1.13 by root, Tue Jul 17 00:24:14 2001 UTC vs. Revision 1.97 by root, Mon Dec 4 13:47:56 2006 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.13 by root, Tue Jul 17 00:24:14 2001 UTC vs.
Revision 1.97 by root, Mon Dec 4 13:47:56 2006 UTC