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

Comparing Coro/Coro.pm (file contents):
Revision 1.4 by root, Tue Jul 3 05:05:45 2001 UTC vs.
Revision 1.80 by root, Mon Nov 6 19:56:26 2006 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	Coro - create and 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 Exporter::;
		41
		42	our $idle; # idle coroutine
		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
		95
		96	$main = new Coro;
		97
		98	=item $current (or as function: current)
51		99
52	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
53		101
54	=cut	102	=cut
55		103
56	$main = $current = _newprocess {	104	# maybe some other module used Coro::Specific before...
57	# never being called	105	if ($current) {
		106	$main->{specific} = $current->{specific};
		107	}
		108
		109	$current = $main;
		110
		111	sub current() { $current }
		112
		113	=item $idle
		114
		115	The coroutine to switch to when no other coroutine is running. The default
		116	implementation prints "FATAL: deadlock detected" and exits.
		117
		118	=cut
		119
		120	# should be done using priorities :(
		121	$idle = new Coro sub {
		122	print STDERR "FATAL: deadlock detected\n";
		123	exit(51);
58	};	124	};
59		125
60	=item $error, $error_msg, $error_coro	126	# this coroutine is necessary because a coroutine
		127	# cannot destroy itself.
		128	my @destroy;
		129	my $manager;
		130	$manager = new Coro sub {
		131	while () {
		132	# by overwriting the state object with the manager we destroy it
		133	# while still being able to schedule this coroutine (in case it has
		134	# been readied multiple times. this is harmless since the manager
		135	# can be called as many times as neccessary and will always
		136	# remove itself from the runqueue
		137	while (@destroy) {
		138	my $coro = pop @destroy;
		139	$coro->{status} \|\|= [];
		140	$_->ready for @{delete $coro->{join} \|\| []};
61		141
62	This coroutine will be called on fatal errors. C<$error_msg> and	142	# the next line destroys the _coro_state, but keeps the
63	C<$error_coro> return the error message and the error-causing coroutine,	143	# process itself intact (we basically make it a zombie
64	respectively.	144	# process that always runs the manager thread, so it's possible
65		145	# to transfer() to this process).
66	=cut	146	$coro->{_coro_state} = $manager->{_coro_state};
67		147	}
68	$error_msg =	148	&schedule;
69	$error_coro = undef;	149	}
70
71	$error = _newprocess {
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";
73	exit 250;
74	};	150	};
75		151
76	=item $coro = new $coderef [, @args]	152	# static methods. not really.
77		153
78	Create a new coroutine and return it. The first C<resume> call to this	154	=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		155
		156	=head2 STATIC METHODS
		157
		158	Static methods are actually functions that operate on the current process only.
		159
		160	=over 4
		161
		162	=item async { ... } [@args...]
		163
		164	Create a new asynchronous process and return it's process object
		165	(usually unused). When the sub returns the new process is automatically
		166	terminated.
		167
		168	When the coroutine dies, the program will exit, just as in the main
		169	program.
		170
		171	# create a new coroutine that just prints its arguments
		172	async {
		173	print "@_\n";
		174	} 1,2,3,4;
		175
83	=cut	176	=cut
		177
		178	sub async(&@) {
		179	my $pid = new Coro @_;
		180	$manager->ready; # this ensures that the stack is cloned from the manager
		181	$pid->ready;
		182	$pid;
		183	}
		184
		185	=item schedule
		186
		187	Calls the scheduler. Please note that the current process will not be put
		188	into the ready queue, so calling this function usually means you will
		189	never be called again.
		190
		191	=cut
		192
		193	=item cede
		194
		195	"Cede" to other processes. This function puts the current process into the
		196	ready queue and calls C<schedule>, which has the effect of giving up the
		197	current "timeslice" to other coroutines of the same or higher priority.
		198
		199	=cut
		200
		201	=item terminate [arg...]
		202
		203	Terminates the current process with the given status values (see L<cancel>).
		204
		205	=cut
		206
		207	sub terminate {
		208	$current->cancel (@_);
		209	}
		210
		211	=back
		212
		213	# dynamic methods
		214
		215	=head2 PROCESS METHODS
		216
		217	These are the methods you can call on process objects.
		218
		219	=over 4
		220
		221	=item new Coro \&sub [, @args...]
		222
		223	Create a new process and return it. When the sub returns the process
		224	automatically terminates as if C<terminate> with the returned values were
		225	called. To make the process run you must first put it into the ready queue
		226	by calling the ready method.
		227
		228	=cut
		229
		230	sub _newcoro {
		231	terminate &{+shift};
		232	}
84		233
85	sub new {	234	sub new {
86	my $class = $_[0];	235	my $class = shift;
87	my $proc = $_[1];	236	bless {
88	bless _newprocess {	237	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
89	do {
90	eval { &$proc->resume };
91	if ($@) {
92	($error_msg, $error_coro) = ($@, $current);
93	$error->resume;
94	}
95	} while (1);
96	}, $class;	238	}, $class;
97	}	239	}
98		240
99	=item $coro->resume	241	=item $process->ready
100		242
101	Resume execution at the given coroutine.	243	Put the given process into the ready queue.
102		244
103	=cut	245	=cut
104		246
105	my $prev;	247	=item $process->cancel (arg...)
106		248
107	sub resume {	249	Terminates the given process and makes it return the given arguments as
108	$prev = $current; $current = $_[0];	250	status (default: the empty list).
109	_transfer($prev, $current);	251
		252	=cut
		253
		254	sub cancel {
		255	my $self = shift;
		256	$self->{status} = [@_];
		257	push @destroy, $self;
		258	$manager->ready;
		259	&schedule if $current == $self;
110	}	260	}
		261
		262	=item $process->join
		263
		264	Wait until the coroutine terminates and return any values given to the
		265	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		266	from multiple processes.
		267
		268	=cut
		269
		270	sub join {
		271	my $self = shift;
		272	unless ($self->{status}) {
		273	push @{$self->{join}}, $current;
		274	&schedule;
		275	}
		276	wantarray ? @{$self->{status}} : $self->{status}[0];
		277	}
		278
		279	=item $oldprio = $process->prio($newprio)
		280
		281	Sets (or gets, if the argument is missing) the priority of the
		282	process. Higher priority processes get run before lower priority
		283	processes. Priorities are small signed integers (currently -4 .. +3),
		284	that you can refer to using PRIO_xxx constants (use the import tag :prio
		285	to get then):
		286
		287	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		288	3 > 1 > 0 > -1 > -3 > -4
		289
		290	# set priority to HIGH
		291	current->prio(PRIO_HIGH);
		292
		293	The idle coroutine ($Coro::idle) always has a lower priority than any
		294	existing coroutine.
		295
		296	Changing the priority of the current process will take effect immediately,
		297	but changing the priority of processes in the ready queue (but not
		298	running) will only take effect after the next schedule (of that
		299	process). This is a bug that will be fixed in some future version.
		300
		301	=cut
		302
		303	sub prio {
		304	my $old = $_[0]{prio};
		305	$_[0]{prio} = $_[1] if @_ > 1;
		306	$old;
		307	}
		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	=cut
		315
		316	sub nice {
		317	$_[0]{prio} -= $_[1];
		318	}
		319
		320	=item $olddesc = $process->desc($newdesc)
		321
		322	Sets (or gets in case the argument is missing) the description for this
		323	process. This is just a free-form string you can associate with a process.
		324
		325	=cut
		326
		327	sub desc {
		328	my $old = $_[0]{desc};
		329	$_[0]{desc} = $_[1] if @_ > 1;
		330	$old;
		331	}
		332
		333	=back
		334
		335	=cut
111		336
112	1;	337	1;
113		338
114	=back	339	=head1 BUGS/LIMITATIONS
115		340
116	=head1 BUGS	341	- you must make very sure that no coro is still active on global
		342	destruction. very bad things might happen otherwise (usually segfaults).
117		343
118	This module has not yet been extensively tested.	344	- this module is not thread-safe. You should only ever use this module
		345	from the same thread (this requirement might be losened in the future
		346	to allow per-thread schedulers, but Coro::State does not yet allow
		347	this).
119		348
120	=head1 SEE ALSO	349	=head1 SEE ALSO
121		350
122	L<Coro::Process>, L<Coro::Signal>.	351	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
		352
		353	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		354
		355	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		356
		357	Embedding: L<Coro:MakeMaker>
123		358
124	=head1 AUTHOR	359	=head1 AUTHOR
125		360
126	Marc Lehmann <pcg@goof.com>	361	Marc Lehmann <schmorp@schmorp.de>
127	http://www.goof.com/pcg/marc/	362	http://home.schmorp.de/
128		363
129	=cut	364	=cut
130		365

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Comparing Coro/Coro.pm (file contents): Revision 1.4 by root, Tue Jul 3 05:05:45 2001 UTC vs. Revision 1.80 by root, Mon Nov 6 19:56:26 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.4 by root, Tue Jul 3 05:05:45 2001 UTC vs.
Revision 1.80 by root, Mon Nov 6 19:56:26 2006 UTC