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

Comparing Coro/Coro.pm (file contents):
Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs.
Revision 1.83 by root, Fri Nov 24 15:34:33 2006 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	Coro - create an manage coroutines	3	Coro - coroutine process abstraction
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use Coro;	7	use Coro;
8		8
9	$new = new Coro sub {	9	async {
10	print "in coroutine, switching back\n";	10	# some asynchronous thread of execution
11	$Coro::main->resume;
12	print "in coroutine again, switching back\n";
13	$Coro::main->resume;
14	};	11	};
15		12
16	print "in main, switching to coroutine\n";	13	# alternatively create an async process like this:
17	$new->resume;	14
18	print "back in main, switch to coroutine again\n";	15	sub some_func : Coro {
19	$new->resume;	16	# some more async code
20	print "back in main\n";	17	}
		18
		19	cede;
21		20
22	=head1 DESCRIPTION	21	=head1 DESCRIPTION
23		22
24	This module implements coroutines. Coroutines, similar to continuations,	23	This module collection manages coroutines. Coroutines are similar to
25	allow you to run more than one "thread of execution" in parallel. Unlike	24	threads but don't run in parallel.
26	threads this, only voluntary switching is used so locking problems are
27	greatly reduced.
28		25
29	Although this is the "main" module of the Coro family it provides only	26	In this module, coroutines are defined as "callchain + lexical variables
30	low-level functionality. See L<Coro::Process> and related modules for a	27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
31	more useful process abstraction including scheduling.	28	callchain, it's own set of lexicals and it's own set of perl's most
		29	important global variables.
		30
		31	=cut
		32
		33	package Coro;
		34
		35	use strict;
		36	no warnings "uninitialized";
		37
		38	use Coro::State;
		39
		40	use base qw(Coro::State Exporter);
		41
		42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
		45
		46	our $VERSION = '2.5';
		47
		48	our @EXPORT = qw(async cede schedule terminate current);
		49	our %EXPORT_TAGS = (
		50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		51	);
		52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
		53
		54	{
		55	my @async;
		56	my $init;
		57
		58	# this way of handling attributes simply is NOT scalable ;()
		59	sub import {
		60	no strict 'refs';
		61
		62	Coro->export_to_level(1, @_);
		63
		64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		66	my ($package, $ref) = (shift, shift);
		67	my @attrs;
		68	for (@_) {
		69	if ($_ eq "Coro") {
		70	push @async, $ref;
		71	unless ($init++) {
		72	eval q{
		73	sub INIT {
		74	&async(pop @async) while @async;
		75	}
		76	};
		77	}
		78	} else {
		79	push @attrs, $_;
		80	}
		81	}
		82	return $old ? $old->($package, $ref, @attrs) : @attrs;
		83	};
		84	}
		85
		86	}
32		87
33	=over 4	88	=over 4
34		89
35	=cut
36
37	package Coro;
38
39	BEGIN {
40	$VERSION = 0.01;
41
42	require XSLoader;
43	XSLoader::load Coro, $VERSION;
44	}
45
46	=item $main	90	=item $main
47		91
48	This coroutine represents the main program.	92	This coroutine represents the main program.
49		93
50	=item $current	94	=cut
51		95
		96	$main = new Coro;
		97
		98	=item $current (or as function: current)
		99
52	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$main> (of course).
53		102
54	=cut	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.
55		106
56	$main = $current = _newprocess {	107	=cut
57	# never being called	108
		109	# maybe some other module used Coro::Specific before...
		110	if ($current) {
		111	$main->{specific} = $current->{specific};
		112	}
		113
		114	$current = $main;
		115
		116	sub current() { $current }
		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.
		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 wakes up some
		126	coroutine.
		127
		128	=cut
		129
		130	$idle = sub {
		131	print STDERR "FATAL: deadlock detected\n";
		132	exit (51);
58	};	133	};
59		134
60	=item $error, $error_msg, $error_coro	135	# this coroutine is necessary because a coroutine
		136	# cannot destroy itself.
		137	my @destroy;
		138	my $manager;
		139	$manager = new Coro sub {
		140	while () {
		141	# by overwriting the state object with the manager we destroy it
		142	# while still being able to schedule this coroutine (in case it has
		143	# been readied multiple times. this is harmless since the manager
		144	# can be called as many times as neccessary and will always
		145	# remove itself from the runqueue
		146	while (@destroy) {
		147	my $coro = pop @destroy;
		148	$coro->{status} \|\|= [];
		149	$_->ready for @{delete $coro->{join} \|\| []};
61		150
62	This coroutine will be called on fatal errors. C<$error_msg> and	151	# the next line destroys the coro state, but keeps the
63	C<$error_coro> return the error message and the error-causing coroutine,	152	# process itself intact (we basically make it a zombie
64	respectively.	153	# process that always runs the manager thread, so it's possible
65		154	# to transfer() to this process).
66	=cut	155	$coro->_clone_state_from ($manager);
67		156	}
68	$error_msg =	157	&schedule;
69	$error_coro = undef;	158	}
70
71	$error = _newprocess {
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";
73	exit 250;
74	};	159	};
75		160
76	=item $coro = new $coderef [, @args]	161	# static methods. not really.
77		162
78	Create a new coroutine and return it. The first C<resume> call to this	163	=back
79	coroutine will start execution at the given coderef. If it returns it
80	should return a coroutine to switch to. If, after returning, the coroutine
81	is C<resume>d again it starts execution again at the givne coderef.
82		164
		165	=head2 STATIC METHODS
		166
		167	Static methods are actually functions that operate on the current process only.
		168
		169	=over 4
		170
		171	=item async { ... } [@args...]
		172
		173	Create a new asynchronous process and return it's process object
		174	(usually unused). When the sub returns the new process is automatically
		175	terminated.
		176
		177	When the coroutine dies, the program will exit, just as in the main
		178	program.
		179
		180	# create a new coroutine that just prints its arguments
		181	async {
		182	print "@_\n";
		183	} 1,2,3,4;
		184
83	=cut	185	=cut
		186
		187	sub async(&@) {
		188	my $pid = new Coro @_;
		189	$manager->ready; # this ensures that the stack is cloned from the manager
		190	$pid->ready;
		191	$pid;
		192	}
		193
		194	=item schedule
		195
		196	Calls the scheduler. Please note that the current process will not be put
		197	into the ready queue, so calling this function usually means you will
		198	never be called again.
		199
		200	=cut
		201
		202	=item cede
		203
		204	"Cede" to other processes. This function puts the current process into the
		205	ready queue and calls C<schedule>, which has the effect of giving up the
		206	current "timeslice" to other coroutines of the same or higher priority.
		207
		208	=cut
		209
		210	=item terminate [arg...]
		211
		212	Terminates the current process with the given status values (see L<cancel>).
		213
		214	=cut
		215
		216	sub terminate {
		217	$current->cancel (@_);
		218	}
		219
		220	=back
		221
		222	# dynamic methods
		223
		224	=head2 PROCESS METHODS
		225
		226	These are the methods you can call on process objects.
		227
		228	=over 4
		229
		230	=item new Coro \&sub [, @args...]
		231
		232	Create a new process and return it. When the sub returns the process
		233	automatically terminates as if C<terminate> with the returned values were
		234	called. To make the process run you must first put it into the ready queue
		235	by calling the ready method.
		236
		237	=cut
		238
		239	sub _newcoro {
		240	terminate &{+shift};
		241	}
84		242
85	sub new {	243	sub new {
86	my $class = $_[0];	244	my $class = shift;
87	my $proc = $_[1];
88	bless _newprocess {
89	do {
90	eval { &$proc->resume };
91	if ($@) {
92	($error_msg, $error_coro) = ($@, $current);
93	$error->resume;
94	}
95	} while ();
96	}, $class;
97	}
98		245
99	=item $coro->resume	246	$class->SUPER::new (\&_newcoro, @_)
100
101	Resume execution at the given coroutine.
102
103	=cut
104
105	my $prev;
106
107	sub resume {
108	$prev = $current; $current = $_[0];
109	_transfer($prev, $current);
110	}	247	}
		248
		249	=item $process->ready
		250
		251	Put the given process into the ready queue.
		252
		253	=cut
		254
		255	=item $process->cancel (arg...)
		256
		257	Terminates the given process and makes it return the given arguments as
		258	status (default: the empty list).
		259
		260	=cut
		261
		262	sub cancel {
		263	my $self = shift;
		264	$self->{status} = [@_];
		265	push @destroy, $self;
		266	$manager->ready;
		267	&schedule if $current == $self;
		268	}
		269
		270	=item $process->join
		271
		272	Wait until the coroutine terminates and return any values given to the
		273	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		274	from multiple processes.
		275
		276	=cut
		277
		278	sub join {
		279	my $self = shift;
		280	unless ($self->{status}) {
		281	push @{$self->{join}}, $current;
		282	&schedule;
		283	}
		284	wantarray ? @{$self->{status}} : $self->{status}[0];
		285	}
		286
		287	=item $oldprio = $process->prio ($newprio)
		288
		289	Sets (or gets, if the argument is missing) the priority of the
		290	process. Higher priority processes get run before lower priority
		291	processes. Priorities are small signed integers (currently -4 .. +3),
		292	that you can refer to using PRIO_xxx constants (use the import tag :prio
		293	to get then):
		294
		295	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		296	3 > 1 > 0 > -1 > -3 > -4
		297
		298	# set priority to HIGH
		299	current->prio(PRIO_HIGH);
		300
		301	The idle coroutine ($Coro::idle) always has a lower priority than any
		302	existing coroutine.
		303
		304	Changing the priority of the current process will take effect immediately,
		305	but changing the priority of processes in the ready queue (but not
		306	running) will only take effect after the next schedule (of that
		307	process). This is a bug that will be fixed in some future version.
		308
		309	=item $newprio = $process->nice ($change)
		310
		311	Similar to C<prio>, but subtract the given value from the priority (i.e.
		312	higher values mean lower priority, just as in unix).
		313
		314	=item $olddesc = $process->desc ($newdesc)
		315
		316	Sets (or gets in case the argument is missing) the description for this
		317	process. This is just a free-form string you can associate with a process.
		318
		319	=cut
		320
		321	sub desc {
		322	my $old = $_[0]{desc};
		323	$_[0]{desc} = $_[1] if @_ > 1;
		324	$old;
		325	}
		326
		327	=back
		328
		329	=cut
111		330
112	1;	331	1;
113		332
114	=back	333	=head1 BUGS/LIMITATIONS
115		334
116	=head1 BUGS	335	- you must make very sure that no coro is still active on global
		336	destruction. very bad things might happen otherwise (usually segfaults).
117		337
118	This module has not yet been extensively tested.	338	- this module is not thread-safe. You should only ever use this module
		339	from the same thread (this requirement might be losened in the future
		340	to allow per-thread schedulers, but Coro::State does not yet allow
		341	this).
119		342
120	=head1 SEE ALSO	343	=head1 SEE ALSO
121		344
122	L<Coro::Process>, L<Coro::Signal>.	345	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
		346
		347	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		348
		349	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		350
		351	Embedding: L<Coro:MakeMaker>
123		352
124	=head1 AUTHOR	353	=head1 AUTHOR
125		354
126	Marc Lehmann <pcg@goof.com>	355	Marc Lehmann <schmorp@schmorp.de>
127	http://www.goof.com/pcg/marc/	356	http://home.schmorp.de/
128		357
129	=cut	358	=cut
130		359

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Comparing Coro/Coro.pm (file contents): Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs. Revision 1.83 by root, Fri Nov 24 15:34:33 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs.
Revision 1.83 by root, Fri Nov 24 15:34:33 2006 UTC