[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 1.92 by root, Fri Dec 1 03:47:55 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 = 0.03;	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	}
63		87
64	my $idle = new Coro sub {	88	=over 4
65	&yield while 1;
66	};
67		89
68	=item $main	90	=item $main
69		91
70	This coroutine represents the main program.	92	This coroutine represents the main program.
71		93
72	=cut	94	=cut
73		95
74	$main = new Coro;	96	$main = new Coro;
75		97
76	=item $current	98	=item $current (or as function: current)
77		99
78	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$main> (of course).
		102
		103	This variable is B<strictly> I<read-only>. It is provided for performance
		104	reasons. If performance is not essentiel you are encouraged to use the
		105	C<Coro::current> function instead.
79		106
80	=cut	107	=cut
81		108
82	# maybe some other module used Coro::Specific before...	109	# maybe some other module used Coro::Specific before...
83	if ($current) {	110	if ($current) {
84	$main->{specific} = $current->{specific};	111	$main->{specific} = $current->{specific};
85	}	112	}
86		113
87	$current = $main;	114	$current = $main;
88		115
89	# we really need priorities...	116	sub current() { $current }
90	my @ready = (); # the ready queue. hehe, rather broken ;)	117
		118	=item $idle
		119
		120	A callback that is called whenever the scheduler finds no ready coroutines
		121	to run. The default implementation prints "FATAL: deadlock detected" and
		122	exits, because the program has no other way to continue.
		123
		124	This hook is overwritten by modules such as C<Coro::Timer> and
		125	C<Coro::Event> to wait on an external event that hopefully wake up a
		126	coroutine so the scheduler can run it.
		127
		128	Please note that if your callback recursively invokes perl (e.g. for event
		129	handlers), then it must be prepared to be called recursively.
		130
		131	=cut
		132
		133	$idle = sub {
		134	print STDERR "FATAL: deadlock detected\n";
		135	exit (51);
		136	};
		137
		138	# this coroutine is necessary because a coroutine
		139	# cannot destroy itself.
		140	my @destroy;
		141	my $manager; $manager = new Coro sub {
		142	while () {
		143	# by overwriting the state object with the manager we destroy it
		144	# while still being able to schedule this coroutine (in case it has
		145	# been readied multiple times. this is harmless since the manager
		146	# can be called as many times as neccessary and will always
		147	# remove itself from the runqueue
		148	while (@destroy) {
		149	my $coro = pop @destroy;
		150	$coro->{status} \|\|= [];
		151	$_->ready for @{delete $coro->{join} \|\| []};
		152
		153	# the next line destroys the coro state, but keeps the
		154	# coroutine itself intact (we basically make it a zombie
		155	# coroutine that always runs the manager thread, so it's possible
		156	# to transfer() to this coroutine).
		157	$coro->_clone_state_from ($manager);
		158	}
		159	&schedule;
		160	}
		161	};
91		162
92	# static methods. not really.	163	# static methods. not really.
93		164
		165	=back
		166
94	=head2 STATIC METHODS	167	=head2 STATIC METHODS
95		168
96	Static methods are actually functions that operate on the current process only.	169	Static methods are actually functions that operate on the current coroutine only.
97		170
98	=over 4	171	=over 4
99		172
100	=item async { ... };	173	=item async { ... } [@args...]
101		174
102	Create a new asynchronous process and return it's process object	175	Create a new asynchronous coroutine and return it's coroutine object
103	(usually unused). When the sub returns the new process is automatically	176	(usually unused). When the sub returns the new coroutine is automatically
104	terminated.	177	terminated.
105		178
106	=cut	179	Calling C<exit> in a coroutine will not work correctly, so do not do that.
107		180
		181	When the coroutine dies, the program will exit, just as in the main
		182	program.
		183
		184	# create a new coroutine that just prints its arguments
		185	async {
		186	print "@_\n";
		187	} 1,2,3,4;
		188
		189	=cut
		190
108	sub async(&) {	191	sub async(&@) {
109	(new Coro $_[0])->ready;	192	my $pid = new Coro @_;
		193	$pid->ready;
		194	$pid
110	}	195	}
111		196
112	=item schedule	197	=item schedule
113		198
114	Calls the scheduler. Please note that the current process will not be put	199	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	200	into the ready queue, so calling this function usually means you will
116	never be called again.	201	never be called again unless something else (e.g. an event handler) calls
		202	ready.
117		203
118	=cut	204	The canonical way to wait on external events is this:
119		205
120	my $prev;	206	{
		207	# remember current coroutine
		208	my $current = $Coro::current;
121		209
122	sub schedule {	210	# register a hypothetical event handler
123	($prev, $current) = ($current, shift @ready);	211	on_event_invoke sub {
124	Coro::State::transfer($prev, $current);	212	# 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;	213	$current->ready;
136	&schedule;	214	undef $current;
137	}	215	};
138		216
		217	# call schedule until event occured.
		218	# in case we are woken up for other reasons
		219	# (current still defined), loop.
		220	Coro::schedule while $current;
		221	}
		222
		223	=item cede
		224
		225	"Cede" to other coroutines. This function puts the current coroutine into the
		226	ready queue and calls C<schedule>, which has the effect of giving up the
		227	current "timeslice" to other coroutines of the same or higher priority.
		228
139	=item terminate	229	=item terminate [arg...]
140		230
141	Terminates the current process.	231	Terminates the current coroutine with the given status values (see L<cancel>).
142		232
143	=cut	233	=cut
144		234
145	sub terminate {	235	sub terminate {
146	&schedule;	236	$current->cancel (@_);
147	}	237	}
148		238
149	=back	239	=back
150		240
151	# dynamic methods	241	# dynamic methods
152		242
153	=head2 PROCESS METHODS	243	=head2 COROUTINE METHODS
154		244
155	These are the methods you can call on process objects.	245	These are the methods you can call on coroutine objects.
156		246
157	=over 4	247	=over 4
158		248
159	=item new Coro \⊂	249	=item new Coro \&sub [, @args...]
160		250
161	Create a new process and return it. When the sub returns the process	251	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	252	automatically terminates as if C<terminate> with the returned values were
		253	called. To make the coroutine run you must first put it into the ready queue
163	the ready queue by calling the ready method.	254	by calling the ready method.
164		255
		256	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		257
165	=cut	258	=cut
		259
		260	sub _new_coro {
		261	terminate &{+shift};
		262	}
166		263
167	sub new {	264	sub new {
168	my $class = shift;	265	my $class = shift;
		266
		267	$class->SUPER::new (\&_new_coro, @_)
		268	}
		269
		270	=item $success = $coroutine->ready
		271
		272	Put the given coroutine into the ready queue (according to it's priority)
		273	and return true. If the coroutine is already in the ready queue, do nothing
		274	and return false.
		275
		276	=item $is_ready = $coroutine->is_ready
		277
		278	Return wether the coroutine is currently the ready queue or not,
		279
		280	=item $coroutine->cancel (arg...)
		281
		282	Terminates the given coroutine and makes it return the given arguments as
		283	status (default: the empty list).
		284
		285	=cut
		286
		287	sub cancel {
		288	my $self = shift;
		289	$self->{status} = [@_];
		290	push @destroy, $self;
		291	$manager->ready;
		292	&schedule if $current == $self;
		293	}
		294
		295	=item $coroutine->join
		296
		297	Wait until the coroutine terminates and return any values given to the
		298	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		299	from multiple coroutine.
		300
		301	=cut
		302
		303	sub join {
		304	my $self = shift;
		305	unless ($self->{status}) {
		306	push @{$self->{join}}, $current;
		307	&schedule;
		308	}
		309	wantarray ? @{$self->{status}} : $self->{status}[0];
		310	}
		311
		312	=item $oldprio = $coroutine->prio ($newprio)
		313
		314	Sets (or gets, if the argument is missing) the priority of the
		315	coroutine. Higher priority coroutines get run before lower priority
		316	coroutines. Priorities are small signed integers (currently -4 .. +3),
		317	that you can refer to using PRIO_xxx constants (use the import tag :prio
		318	to get then):
		319
		320	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		321	3 > 1 > 0 > -1 > -3 > -4
		322
		323	# set priority to HIGH
		324	current->prio(PRIO_HIGH);
		325
		326	The idle coroutine ($Coro::idle) always has a lower priority than any
		327	existing coroutine.
		328
		329	Changing the priority of the current coroutine will take effect immediately,
		330	but changing the priority of coroutines in the ready queue (but not
		331	running) will only take effect after the next schedule (of that
		332	coroutine). This is a bug that will be fixed in some future version.
		333
		334	=item $newprio = $coroutine->nice ($change)
		335
		336	Similar to C<prio>, but subtract the given value from the priority (i.e.
		337	higher values mean lower priority, just as in unix).
		338
		339	=item $olddesc = $coroutine->desc ($newdesc)
		340
		341	Sets (or gets in case the argument is missing) the description for this
		342	coroutine. This is just a free-form string you can associate with a coroutine.
		343
		344	=cut
		345
		346	sub desc {
169	my $proc = $_[0];	347	my $old = $_[0]{desc};
170	bless {	348	$_[0]{desc} = $_[1] if @_ > 1;
171	_coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc),	349	$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	}	350	}
184		351
185	=back	352	=back
186		353
		354	=head2 UTILITY FUNCTIONS
		355
		356	=over 4
		357
		358	=item unblock_sub { ... }
		359
		360	This utility function takes a BLOCK or code reference and "unblocks" it,
		361	returning the new coderef. This means that the new coderef will return
		362	immediately without blocking, returning nothing, while the original code
		363	ref will be called (with parameters) from within its own coroutine.
		364
		365	The reason this fucntion exists is that many event libraries (such as the
		366	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		367	of thread-safety). This means you must not block within event callbacks,
		368	otherwise you might suffer from crashes or worse.
		369
		370	This function allows your callbacks to block by executing them in another
		371	coroutine where it is safe to block. One example where blocking is handy
		372	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		373	disk.
		374
		375	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		376	creating event callbacks that want to block.
		377
		378	=cut
		379
		380	our @unblock_pool;
		381	our @unblock_queue;
		382	our $UNBLOCK_POOL_SIZE = 2;
		383
		384	sub unblock_handler_ {
		385	while () {
		386	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		387	$cb->(@arg);
		388
		389	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		390	push @unblock_pool, $Coro::current;
		391	schedule;
		392	}
		393	}
		394
		395	our $unblock_scheduler = async {
		396	while () {
		397	while (my $cb = pop @unblock_queue) {
		398	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		399	$handler->{arg} = $cb;
		400	$handler->ready;
		401	cede;
		402	}
		403
		404	schedule;
		405	}
		406	};
		407
		408	sub unblock_sub(&) {
		409	my $cb = shift;
		410
		411	sub {
		412	push @unblock_queue, [$cb, @_];
		413	$unblock_scheduler->ready;
		414	}
		415	}
		416
		417	=back
		418
187	=cut	419	=cut
188		420
189	1;	421	1;
190		422
		423	=head1 BUGS/LIMITATIONS
		424
		425	- you must make very sure that no coro is still active on global
		426	destruction. very bad things might happen otherwise (usually segfaults).
		427
		428	- this module is not thread-safe. You should only ever use this module
		429	from the same thread (this requirement might be losened in the future
		430	to allow per-thread schedulers, but Coro::State does not yet allow
		431	this).
		432
		433	=head1 SEE ALSO
		434
		435	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
		436
		437	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		438
		439	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		440
		441	Embedding: L<Coro:MakeMaker>
		442
191	=head1 AUTHOR	443	=head1 AUTHOR
192		444
193	Marc Lehmann <pcg@goof.com>	445	Marc Lehmann <schmorp@schmorp.de>
194	http://www.goof.com/pcg/marc/	446	http://home.schmorp.de/
195		447
196	=cut	448	=cut
197		449

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing Coro/Coro.pm (file contents): Revision 1.8 by root, Sat Jul 14 22:14:21 2001 UTC vs. Revision 1.92 by root, Fri Dec 1 03:47:55 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 1.92 by root, Fri Dec 1 03:47:55 2006 UTC