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

Comparing Coro/Coro.pm (file contents):
Revision 1.3 by root, Tue Jul 3 04:02:31 2001 UTC vs.
Revision 1.36 by root, Mon Sep 24 01:36:20 2001 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	This module is still experimental, see the BUGS section below.
30	low-level functionality. See L<Coro::Process> and related modules for a	27
31	more useful process abstraction including scheduling.	28	In this module, coroutines are defined as "callchain + lexical variables
		29	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
		30	callchain, it's own set of lexicals and it's own set of perl's most
		31	important global variables.
		32
		33	=cut
		34
		35	package Coro;
		36
		37	no warnings qw(uninitialized);
		38
		39	use Coro::State;
		40
		41	use base Exporter;
		42
		43	$VERSION = 0.5;
		44
		45	@EXPORT = qw(async cede schedule terminate current);
		46	%EXPORT_TAGS = (
		47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		48	);
		49	@EXPORT_OK = @{$EXPORT_TAGS{prio}};
		50
		51	{
		52	my @async;
		53	my $init;
		54
		55	# this way of handling attributes simply is NOT scalable ;()
		56	sub import {
		57	Coro->export_to_level(1, @_);
		58	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		59	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		60	my ($package, $ref) = (shift, shift);
		61	my @attrs;
		62	for (@_) {
		63	if ($_ eq "Coro") {
		64	push @async, $ref;
		65	unless ($init++) {
		66	eval q{
		67	sub INIT {
		68	&async(pop @async) while @async;
		69	}
		70	};
		71	}
		72	} else {
		73	push @attrs, $_;
		74	}
		75	}
		76	return $old ? $old->($package, $ref, @attrs) : @attrs;
		77	};
		78	}
		79
		80	}
		81
		82	=item $main
		83
		84	This coroutine represents the main program.
		85
		86	=cut
		87
		88	our $main = new Coro;
		89
		90	=item $current (or as function: current)
		91
		92	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		93
		94	=cut
		95
		96	# maybe some other module used Coro::Specific before...
		97	if ($current) {
		98	$main->{specific} = $current->{specific};
		99	}
		100
		101	our $current = $main;
		102
		103	sub current() { $current }
		104
		105	=item $idle
		106
		107	The coroutine to switch to when no other coroutine is running. The default
		108	implementation prints "FATAL: deadlock detected" and exits.
		109
		110	=cut
		111
		112	# should be done using priorities :(
		113	our $idle = new Coro sub {
		114	print STDERR "FATAL: deadlock detected\n";
		115	exit(51);
		116	};
		117
		118	# this coroutine is necessary because a coroutine
		119	# cannot destroy itself.
		120	my @destroy;
		121	my $manager = new Coro sub {
		122	while() {
		123	delete ((pop @destroy)->{_coro_state}) while @destroy;
		124	&schedule;
		125	}
		126	};
		127
		128	# static methods. not really.
		129
		130	=head2 STATIC METHODS
		131
		132	Static methods are actually functions that operate on the current process only.
32		133
33	=over 4	134	=over 4
34		135
35	=cut	136	=item async { ... } [@args...]
36		137
37	package Coro;	138	Create a new asynchronous process and return it's process object
		139	(usually unused). When the sub returns the new process is automatically
		140	terminated.
38		141
39	BEGIN {	142	# create a new coroutine that just prints its arguments
40	$VERSION = 0.01;	143	async {
		144	print "@_\n";
		145	} 1,2,3,4;
41		146
42	require XSLoader;	147	The coderef you submit MUST NOT be a closure that refers to variables
43	XSLoader::load Coro, $VERSION;	148	in an outer scope. This does NOT work. Pass arguments into it instead.
44	}
45		149
46	=item $main
47
48	This coroutine represents the main program.
49
50	=item $current
51
52	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
53
54	=cut	150	=cut
55		151
56	$main = $current = _newprocess {	152	sub async(&@) {
57	# never being called	153	my $pid = new Coro @_;
58	};	154	$manager->ready; # this ensures that the stack is cloned from the manager
		155	$pid->ready;
		156	$pid;
		157	}
59		158
60	=item $error, $error_msg, $error_coro	159	=item schedule
61		160
62	This coroutine will be called on fatal errors. C<$error_msg> and	161	Calls the scheduler. Please note that the current process will not be put
63	C<$error_coro> return the error message and the error-causing coroutine,	162	into the ready queue, so calling this function usually means you will
64	respectively.	163	never be called again.
65		164
66	=cut	165	=cut
67		166
68	$error_msg =	167	=item cede
69	$error_coro = undef;
70		168
71	$error = _newprocess {	169	"Cede" to other processes. This function puts the current process into the
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	170	ready queue and calls C<schedule>, which has the effect of giving up the
73	exit 250;	171	current "timeslice" to other coroutines of the same or higher priority.
74	};
75		172
76	=item $coro = new $coderef [, @args]
77
78	Create a new coroutine and return it. The first C<resume> call to this
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
83	=cut	173	=cut
		174
		175	=item terminate
		176
		177	Terminates the current process.
		178
		179	Future versions of this function will allow result arguments.
		180
		181	=cut
		182
		183	sub terminate {
		184	$current->cancel;
		185	&schedule;
		186	die; # NORETURN
		187	}
		188
		189	=back
		190
		191	# dynamic methods
		192
		193	=head2 PROCESS METHODS
		194
		195	These are the methods you can call on process objects.
		196
		197	=over 4
		198
		199	=item new Coro \&sub [, @args...]
		200
		201	Create a new process and return it. When the sub returns the process
		202	automatically terminates. To start the process you must first put it into
		203	the ready queue by calling the ready method.
		204
		205	The coderef you submit MUST NOT be a closure that refers to variables
		206	in an outer scope. This does NOT work. Pass arguments into it instead.
		207
		208	=cut
		209
		210	sub _newcoro {
		211	terminate &{+shift};
		212	}
84		213
85	sub new {	214	sub new {
86	my $class = $_[0];	215	my $class = shift;
87	my $proc = $_[1];	216	bless {
88	bless _newprocess {	217	_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 ();
96	}, $class;	218	}, $class;
97	}	219	}
98		220
99	=item $coro->resume	221	=item $process->ready
100		222
101	Resume execution at the given coroutine.	223	Put the current process into the ready queue.
102		224
103	=cut	225	=cut
104		226
105	my $prev;	227	=item $process->cancel
106		228
107	sub resume {	229	Like C<terminate>, but terminates the specified process instead.
108	$prev = $current; $current = $_[0];	230
109	_transfer($prev, $current);	231	=cut
		232
		233	sub cancel {
		234	push @destroy, $_[0];
		235	$manager->ready;
		236	&schedule if $current == $_[0];
110	}	237	}
		238
		239	=item $oldprio = $process->prio($newprio)
		240
		241	Sets the priority of the process. Higher priority processes get run before
		242	lower priority processes. Priorities are smalled signed integer (currently
		243	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import
		244	tag :prio to get then):
		245
		246	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		247	3 > 1 > 0 > -1 > -3 > -4
		248
		249	# set priority to HIGH
		250	current->prio(PRIO_HIGH);
		251
		252	The idle coroutine ($Coro::idle) always has a lower priority than any
		253	existing coroutine.
		254
		255	Changing the priority of the current process will take effect immediately,
		256	but changing the priority of processes in the ready queue (but not
		257	running) will only take effect after the next schedule (of that
		258	process). This is a bug that will be fixed in some future version.
		259
		260	=cut
		261
		262	sub prio {
		263	my $old = $_[0]{prio};
		264	$_[0]{prio} = $_[1] if @_ > 1;
		265	$old;
		266	}
		267
		268	=item $newprio = $process->nice($change)
		269
		270	Similar to C<prio>, but subtract the given value from the priority (i.e.
		271	higher values mean lower priority, just as in unix).
		272
		273	=cut
		274
		275	sub nice {
		276	$_[0]{prio} -= $_[1];
		277	}
		278
		279	=back
		280
		281	=cut
111		282
112	1;	283	1;
113		284
114	=back	285	=head1 BUGS/LIMITATIONS
115		286
116	=head1 BUGS	287	- you must make very sure that no coro is still active on global destruction.
117		288	very bad things might happen otherwise (usually segfaults).
118	This module has not yet been extensively tested.	289	- this module is not thread-safe. You must only ever use this module from
		290	the same thread (this requirement might be loosened in the future to
		291	allow per-thread schedulers, but Coro::State does not yet allow this).
119		292
120	=head1 SEE ALSO	293	=head1 SEE ALSO
121		294
122	L<Coro::Process>, L<Coro::Signal>.	295	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		296	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		297	L<Coro::Handle>, L<Coro::Socket>.
123		298
124	=head1 AUTHOR	299	=head1 AUTHOR
125		300
126	Marc Lehmann <pcg@goof.com>	301	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	302	http://www.goof.com/pcg/marc/

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Comparing Coro/Coro.pm (file contents): Revision 1.3 by root, Tue Jul 3 04:02:31 2001 UTC vs. Revision 1.36 by root, Mon Sep 24 01:36:20 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.3 by root, Tue Jul 3 04:02:31 2001 UTC vs.
Revision 1.36 by root, Mon Sep 24 01:36:20 2001 UTC