[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 1.13 by root, Tue Jul 17 00:24:14 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		22
26	This module implements coroutines. Coroutines, similar to continuations,	23	=cut
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		24
31	Although this is the "main" module of the Coro family it provides only	25	package Coro;
32	low-level functionality. See L<Coro::Process> and related modules for a	26
33	more useful process abstraction including scheduling.	27	use Coro::State;
		28
		29	use base Exporter;
		30
		31	$VERSION = 0.05;
		32
		33	@EXPORT = qw(async yield schedule terminate);
		34	@EXPORT_OK = qw($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	}
		62	}
		63
		64	=item $main
		65
		66	This coroutine represents the main program.
		67
		68	=cut
		69
		70	our $main = new Coro;
		71
		72	=item $current
		73
		74	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		75
		76	=cut
		77
		78	# maybe some other module used Coro::Specific before...
		79	if ($current) {
		80	$main->{specific} = $current->{specific};
		81	}
		82
		83	our $current = $main;
		84
		85	=item $idle
		86
		87	The coroutine to switch to when no other coroutine is running. The default
		88	implementation prints "FATAL: deadlock detected" and exits.
		89
		90	=cut
		91
		92	# should be done using priorities :(
		93	our $idle = new Coro sub {
		94	print STDERR "FATAL: deadlock detected\n";
		95	exit(51);
		96	};
		97
		98	# we really need priorities...
		99	## my @ready; #d#
		100	our @ready = (); # the ready queue. hehe, rather broken ;)
		101
		102	# static methods. not really.
		103
		104	=head2 STATIC METHODS
		105
		106	Static methods are actually functions that operate on the current process only.
34		107
35	=over 4	108	=over 4
36		109
37	=cut	110	=item async { ... } [@args...]
38		111
39	package Coro;	112	Create a new asynchronous process and return it's process object
		113	(usually unused). When the sub returns the new process is automatically
		114	terminated.
40		115
41	BEGIN {	116	# create a new coroutine that just prints its arguments
42	$VERSION = 0.03;	117	async {
		118	print "@_\n";
		119	} 1,2,3,4;
43		120
44	require XSLoader;	121	The coderef you submit MUST NOT be a closure that refers to variables
45	XSLoader::load Coro, $VERSION;	122	in an outer scope. This does NOT work. Pass arguments into it instead.
46	}
47		123
48	=item $coro = new [$coderef [, @args]]
49
50	Create a new coroutine and return it. The first C<transfer> call to this
51	coroutine will start execution at the given coderef. If, the subroutine
52	returns it will be executed again.
53
54	If the coderef is omitted this function will create a new "empty"
55	coroutine, i.e. a coroutine that cannot be transfered to but can be used
56	to save the current coroutine in.
57
58	=cut	124	=cut
		125
		126	sub async(&@) {
		127	my $pid = new Coro @_;
		128	$pid->ready;
		129	$pid;
		130	}
		131
		132	=item schedule
		133
		134	Calls the scheduler. Please note that the current process will not be put
		135	into the ready queue, so calling this function usually means you will
		136	never be called again.
		137
		138	=cut
		139
		140	my $prev;
		141
		142	sub schedule {
		143	# should be done using priorities :(
		144	($prev, $current) = ($current, shift @ready \|\| $idle);
		145	Coro::State::transfer($prev, $current);
		146	}
		147
		148	=item yield
		149
		150	Yield to other processes. This function puts the current process into the
		151	ready queue and calls C<schedule>.
		152
		153	=cut
		154
		155	sub yield {
		156	$current->ready;
		157	&schedule;
		158	}
		159
		160	=item terminate
		161
		162	Terminates the current process.
		163
		164	Future versions of this function will allow result arguments.
		165
		166	=cut
		167
		168	sub terminate {
		169	$current->{_results} = [@_];
		170	&schedule;
		171	}
		172
		173	=back
		174
		175	# dynamic methods
		176
		177	=head2 PROCESS METHODS
		178
		179	These are the methods you can call on process objects.
		180
		181	=over 4
		182
		183	=item new Coro \&sub [, @args...]
		184
		185	Create a new process and return it. When the sub returns the process
		186	automatically terminates. To start the process you must first put it into
		187	the ready queue by calling the ready method.
		188
		189	The coderef you submit MUST NOT be a closure that refers to variables
		190	in an outer scope. This does NOT work. Pass arguments into it instead.
		191
		192	=cut
		193
		194	sub _newcoro {
		195	terminate &{+shift};
		196	}
59		197
60	sub new {	198	sub new {
61	my $class = $_[0];	199	my $class = shift;
62	my $proc = $_[1] \|\| sub { die "tried to transfer to an empty coroutine" };	200	bless {
63	bless _newprocess {	201	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
64	do {
65	eval { &$proc };
66	if ($@) {
67	$error_msg = $@;
68	$error_coro = _newprocess { };
69	&transfer($error_coro, $error);
70	}
71	} while (1);
72	}, $class;	202	}, $class;
73	}	203	}
74		204
75	=item $prev->transfer($next)	205	=item $process->ready
76		206
77	Save the state of the current subroutine in C<$prev> and switch to the	207	Put the current process into the ready queue.
78	coroutine saved in C<$next>.
79		208
80	The "state" of a subroutine only ever includes scope, i.e. lexical
81	variables and the current execution state. It does not save/restore any
82	global variables such as C<$_> 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
95	=cut	209	=cut
96		210
97	# I call the _transfer function from a perl function	211	sub ready {
98	# because that way perl saves all important things on	212	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	}	213	}
104		214
105	=item $error, $error_msg, $error_coro	215	=back
106		216
107	This coroutine will be called on fatal errors. C<$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
111	=cut	217	=cut
112
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		218
121	1;	219	1;
122		220
123	=back
124
125	=head1 BUGS
126
127	This module has not yet been extensively tested.
128
129	=head1 SEE ALSO	221	=head1 SEE ALSO
130		222
131	L<Coro::Process>, L<Coro::Signal>.	223	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		224	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
132		225
133	=head1 AUTHOR	226	=head1 AUTHOR
134		227
135	Marc Lehmann <pcg@goof.com>	228	Marc Lehmann <pcg@goof.com>
136	http://www.goof.com/pcg/marc/	229	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 1.13 by root, Tue Jul 17 00:24:14 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 1.13 by root, Tue Jul 17 00:24:14 2001 UTC