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

Comparing Coro/Coro.pm (file contents):
Revision 1.6 by root, Tue Jul 10 21:19:47 2001 UTC vs.
Revision 1.19 by root, Sat Jul 21 03:44:06 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	This module collection manages coroutines. Coroutines are similar to
27	allow you to run more than one "thread of execution" in parallel. Unlike	24	Threads but don't run in parallel.
28	threads this, only voluntary switching is used so locking problems are
29	greatly reduced.
30		25
31	Although this is the "main" module of the Coro family it provides only	26	This module is still experimental, see the BUGS section below.
32	low-level functionality. See L<Coro::Process> and related modules for a	27
33	more useful process abstraction including scheduling.	28	=cut
		29
		30	package Coro;
		31
		32	use Coro::State;
		33
		34	use base Exporter;
		35
		36	$VERSION = 0.09;
		37
		38	@EXPORT = qw(async yield schedule terminate current);
		39	@EXPORT_OK = qw($current);
		40
		41	{
		42	use subs 'async';
		43
		44	my @async;
		45
		46	# this way of handling attributes simply is NOT scalable ;()
		47	sub import {
		48	Coro->export_to_level(1, @_);
		49	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		50	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		51	my ($package, $ref) = (shift, shift);
		52	my @attrs;
		53	for (@_) {
		54	if ($_ eq "Coro") {
		55	push @async, $ref;
		56	} else {
		57	push @attrs, $_;
		58	}
		59	}
		60	return $old ? $old->($package, $ref, @attrs) : @attrs;
		61	};
		62	}
		63
		64	sub INIT {
		65	async pop @async while @async;
		66	}
		67	}
		68
		69	=item $main
		70
		71	This coroutine represents the main program.
		72
		73	=cut
		74
		75	our $main = new Coro;
		76
		77	=item $current (or as function: current)
		78
		79	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		80
		81	=cut
		82
		83	# maybe some other module used Coro::Specific before...
		84	if ($current) {
		85	$main->{specific} = $current->{specific};
		86	}
		87
		88	our $current = $main;
		89
		90	sub current() { $current }
		91
		92	=item $idle
		93
		94	The coroutine to switch to when no other coroutine is running. The default
		95	implementation prints "FATAL: deadlock detected" and exits.
		96
		97	=cut
		98
		99	# should be done using priorities :(
		100	our $idle = new Coro sub {
		101	print STDERR "FATAL: deadlock detected\n";
		102	exit(51);
		103	};
		104
		105	# we really need priorities...
		106	my @ready; # the ready queue. hehe, rather broken ;)
		107
		108	# static methods. not really.
		109
		110	=head2 STATIC METHODS
		111
		112	Static methods are actually functions that operate on the current process only.
34		113
35	=over 4	114	=over 4
36		115
37	=cut	116	=item async { ... } [@args...]
38		117
39	package Coro;	118	Create a new asynchronous process and return it's process object
		119	(usually unused). When the sub returns the new process is automatically
		120	terminated.
40		121
41	BEGIN {	122	# create a new coroutine that just prints its arguments
42	$VERSION = 0.03;	123	async {
		124	print "@_\n";
		125	} 1,2,3,4;
43		126
44	require XSLoader;	127	The coderef you submit MUST NOT be a closure that refers to variables
45	XSLoader::load Coro, $VERSION;	128	in an outer scope. This does NOT work. Pass arguments into it instead.
46	}
47		129
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	130	=cut
		131
		132	sub async(&@) {
		133	my $pid = new Coro @_;
		134	$pid->ready;
		135	$pid;
		136	}
		137
		138	=item schedule
		139
		140	Calls the scheduler. Please note that the current process will not be put
		141	into the ready queue, so calling this function usually means you will
		142	never be called again.
		143
		144	=cut
		145
		146	my $prev;
		147
		148	sub schedule {
		149	# should be done using priorities :(
		150	($prev, $current) = ($current, shift @ready \|\| $idle);
		151	Coro::State::transfer($prev, $current);
		152	}
		153
		154	=item yield
		155
		156	Yield to other processes. This function puts the current process into the
		157	ready queue and calls C<schedule>.
		158
		159	=cut
		160
		161	sub yield {
		162	$current->ready;
		163	&schedule;
		164	}
		165
		166	=item terminate
		167
		168	Terminates the current process.
		169
		170	Future versions of this function will allow result arguments.
		171
		172	=cut
		173
		174	sub terminate {
		175	$current->{_results} = [@_];
		176	&schedule;
		177	}
		178
		179	=back
		180
		181	# dynamic methods
		182
		183	=head2 PROCESS METHODS
		184
		185	These are the methods you can call on process objects.
		186
		187	=over 4
		188
		189	=item new Coro \&sub [, @args...]
		190
		191	Create a new process and return it. When the sub returns the process
		192	automatically terminates. To start the process you must first put it into
		193	the ready queue by calling the ready method.
		194
		195	The coderef you submit MUST NOT be a closure that refers to variables
		196	in an outer scope. This does NOT work. Pass arguments into it instead.
		197
		198	=cut
		199
		200	sub _newcoro {
		201	terminate &{+shift};
		202	}
59		203
60	sub new {	204	sub new {
61	my $class = $_[0];	205	my $class = shift;
62	my $proc = $_[1] \|\| sub { die "tried to transfer to an empty coroutine" };	206	bless {
63	bless _newprocess {	207	_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;	208	}, $class;
73	}	209	}
74		210
75	=item $prev->transfer($next)	211	=item $process->ready
76		212
77	Save the state of the current subroutine in $prev and switch to the	213	Put the current process into the ready queue.
78	coroutine saved in $next.
79		214
80	=cut	215	=cut
81		216
82	# I call the _transfer function from a perl function	217	sub ready {
83	# because that way perl saves all important things on	218	push @ready, $_[0];
84	# the stack.
85	sub transfer {
86	_transfer($_[0], $_[1]);
87	}	219	}
88		220
89	=item $error, $error_msg, $error_coro	221	=back
90		222
91	This coroutine will be called on fatal errors. C<$error_msg> and
92	C<$error_coro> return the error message and the error-causing coroutine
93	(NOT an object) respectively. This API might change.
94
95	=cut	223	=cut
96
97	$error_msg =
98	$error_coro = undef;
99
100	$error = _newprocess {
101	print STDERR "FATAL: $error_msg\nprogram aborted\n";
102	exit 50;
103	};
104		224
105	1;	225	1;
106		226
107	=back	227	=head1 BUGS/LIMITATIONS
108		228
109	=head1 BUGS	229	- could be faster, especially when the core would introduce special
110		230	support for coroutines (like it does for threads).
111	This module has not yet been extensively tested.	231	- there is still a memleak on coroutine termination that I could not
		232	identify. Could be as small as a single SV.
		233	- this module is not well-tested.
		234	- if variables or arguments "disappear" (become undef) or become
		235	corrupted please contact the author so he cen iron out the
		236	remaining bugs.
		237	- this module is not thread-safe. You must only ever use this module from
		238	the same thread (this requirement might be loosened in the future to
		239	allow per-thread schedulers, but Coro::Satte does not yet allow this).
112		240
113	=head1 SEE ALSO	241	=head1 SEE ALSO
114		242
115	L<Coro::Process>, L<Coro::Signal>.	243	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		244	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
116		245
117	=head1 AUTHOR	246	=head1 AUTHOR
118		247
119	Marc Lehmann <pcg@goof.com>	248	Marc Lehmann <pcg@goof.com>
120	http://www.goof.com/pcg/marc/	249	http://www.goof.com/pcg/marc/

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Comparing Coro/Coro.pm (file contents): Revision 1.6 by root, Tue Jul 10 21:19:47 2001 UTC vs. Revision 1.19 by root, Sat Jul 21 03:44:06 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.6 by root, Tue Jul 10 21:19:47 2001 UTC vs.
Revision 1.19 by root, Sat Jul 21 03:44:06 2001 UTC