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

Comparing Coro/Coro.pm (file contents):
Revision 1.7 by root, Fri Jul 13 13:05:38 2001 UTC vs.
Revision 1.8 by root, Sat Jul 14 22:14:21 2001 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	Coro - create and manage simple 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	$new->transfer($main);
12	print "in coroutine again, switching back\n";
13	$new->transfer($main);
14	};	11	};
15		12
16	$main = new Coro;	13	# alternatively create an async process like this:
17		14
18	print "in main, switching to coroutine\n";	15	sub some_func : Coro {
19	$main->transfer($new);	16	# some more async code
20	print "back in main, switch to coroutine again\n";	17	}
21	$main->transfer($new);	18
22	print "back in main\n";	19	yield;
23		20
24	=head1 DESCRIPTION	21	=head1 DESCRIPTION
25
26	This module implements coroutines. Coroutines, similar to continuations,
27	allow you to run more than one "thread of execution" in parallel. Unlike
28	threads this, only voluntary switching is used so locking problems are
29	greatly reduced.
30
31	Although this is the "main" module of the Coro family it provides only
32	low-level functionality. See L<Coro::Process> and related modules for a
33	more useful process abstraction including scheduling.
34
35	=over 4
36		22
37	=cut	23	=cut
38		24
39	package Coro;	25	package Coro;
40		26
41	BEGIN {	27	use Coro::State;
42	$VERSION = 0.03;
43		28
44	require XSLoader;	29	use base Exporter;
45	XSLoader::load Coro, $VERSION;	30
		31	$VERSION = 0.03;
		32
		33	@EXPORT = qw(async yield schedule);
		34	@EXPORT_OK = qw($current);
		35
		36	{
		37	use subs 'async';
		38
		39	my @async;
		40
		41	# this way of handling attributes simply is NOT scalable ;()
		42	sub import {
		43	Coro->export_to_level(1, @_);
		44	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		45	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		46	my ($package, $ref) = (shift, shift);
		47	my @attrs;
		48	for (@_) {
		49	if ($_ eq "Coro") {
		50	push @async, $ref;
		51	} else {
		52	push @attrs, @_;
		53	}
		54	}
		55	return $old ? $old->($package, $name, @attrs) : @attrs;
		56	};
		57	}
		58
		59	sub INIT {
		60	async pop @async while @async;
		61	}
46	}	62	}
47		63
48	=item $coro = new [$coderef [, @args]]	64	my $idle = new Coro sub {
		65	&yield while 1;
		66	};
49		67
50	Create a new coroutine and return it. The first C<transfer> call to this	68	=item $main
51	coroutine will start execution at the given coderef. If, the subroutine
52	returns it will be executed again.
53		69
54	If the coderef is omitted this function will create a new "empty"	70	This coroutine represents the main program.
55	coroutine, i.e. a coroutine that cannot be transfered to but can be used	71
56	to save the current coroutine in.	72	=cut
		73
		74	$main = new Coro;
		75
		76	=item $current
		77
		78	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		79
		80	=cut
		81
		82	# maybe some other module used Coro::Specific before...
		83	if ($current) {
		84	$main->{specific} = $current->{specific};
		85	}
		86
		87	$current = $main;
		88
		89	# we really need priorities...
		90	my @ready = (); # the ready queue. hehe, rather broken ;)
		91
		92	# static methods. not really.
		93
		94	=head2 STATIC METHODS
		95
		96	Static methods are actually functions that operate on the current process only.
		97
		98	=over 4
		99
		100	=item async { ... };
		101
		102	Create a new asynchronous process and return it's process object
		103	(usually unused). When the sub returns the new process is automatically
		104	terminated.
		105
		106	=cut
		107
		108	sub async(&) {
		109	(new Coro $_[0])->ready;
		110	}
		111
		112	=item schedule
		113
		114	Calls the scheduler. Please note that the current process will not be put
		115	into the ready queue, so calling this function usually means you will
		116	never be called again.
		117
		118	=cut
		119
		120	my $prev;
		121
		122	sub schedule {
		123	($prev, $current) = ($current, shift @ready);
		124	Coro::State::transfer($prev, $current);
		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;
		136	&schedule;
		137	}
		138
		139	=item terminate
		140
		141	Terminates the current process.
		142
		143	=cut
		144
		145	sub terminate {
		146	&schedule;
		147	}
		148
		149	=back
		150
		151	# dynamic methods
		152
		153	=head2 PROCESS METHODS
		154
		155	These are the methods you can call on process objects.
		156
		157	=over 4
		158
		159	=item new Coro \⊂
		160
		161	Create a new process and return it. When the sub returns the process
		162	automatically terminates. To start the process you must first put it into
		163	the ready queue by calling the ready method.
57		164
58	=cut	165	=cut
59		166
60	sub new {	167	sub new {
		168	my $class = shift;
61	my $class = $_[0];	169	my $proc = $_[0];
62	my $proc = $_[1] \|\| sub { die "tried to transfer to an empty coroutine" };	170	bless {
63	bless _newprocess {	171	_coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc),
64	do {
65	eval { &$proc };
66	if ($@) {
67	$error_msg = $@;
68	$error_coro = _newprocess { };
69	&transfer($error_coro, $error);
70	}
71	} while (1);
72	}, $class;	172	}, $class;
73	}	173	}
74		174
75	=item $prev->transfer($next)	175	=item $process->ready
76		176
77	Save the state of the current subroutine in C<$prev> and switch to the	177	Put the current process into the ready queue.
78	coroutine saved in C<$next>.
79
80	The "state" of a subroutine only ever includes scope, i.e. lexical
81	variables and the current execution state. It does not save/restore any
82	global variables such as C<$_> or C<$@> or any other special or non
83	special variables. So remember that every function call that might call
84	C<transfer> (such as C<Coro::Channel::put>) might clobber any global
85	and/or special variables. Yes, this is by design ;) You cna always create
86	your own process abstraction model that saves these variables.
87
88	The easiest way to do this is to create your own scheduling primitive like this:
89
90	sub schedule {
91	local ($_, $@, ...);
92	$old->transfer($new);
93	}
94		178
95	=cut	179	=cut
96		180
97	# I call the _transfer function from a perl function	181	sub ready {
98	# because that way perl saves all important things on	182	push @ready, $_[0];
99	# the stack. Actually, I'd do it from within XS, but
100	# I couldn't get it to work.
101	sub transfer {
102	_transfer($_[0], $_[1]);
103	}	183	}
104		184
105	=item $error, $error_msg, $error_coro	185	=back
106
107	This coroutine will be called on fatal errors. C<$error_msg> and
108	C<$error_coro> return the error message and the error-causing coroutine
109	(NOT an object) respectively. This API might change.
110		186
111	=cut	187	=cut
112		188
113	$error_msg =
114	$error_coro = undef;
115
116	$error = _newprocess {
117	print STDERR "FATAL: $error_msg\nprogram aborted\n";
118	exit 50;
119	};
120
121	1;	189	1;
122
123	=back
124
125	=head1 BUGS
126
127	This module has not yet been extensively tested.
128
129	=head1 SEE ALSO
130
131	L<Coro::Process>, L<Coro::Signal>.
132		190
133	=head1 AUTHOR	191	=head1 AUTHOR
134		192
135	Marc Lehmann <pcg@goof.com>	193	Marc Lehmann <pcg@goof.com>
136	http://www.goof.com/pcg/marc/	194	http://www.goof.com/pcg/marc/

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Comparing Coro/Coro.pm (file contents): Revision 1.7 by root, Fri Jul 13 13:05:38 2001 UTC vs. Revision 1.8 by root, Sat Jul 14 22:14:21 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.7 by root, Fri Jul 13 13:05:38 2001 UTC vs.
Revision 1.8 by root, Sat Jul 14 22:14:21 2001 UTC