[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 1.20 by root, Sat Jul 21 18:21:45 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	In this module, coroutines are defined as "callchain + lexical variables
		29	+ @_ + $_ + $@ + $^W), that is, a coroutine has it's own callchain, it's
		30	own set of lexicals and it's own set of perl's most important global
		31	variables.
		32
		33	=cut
		34
		35	package Coro;
		36
		37	use Coro::State;
		38
		39	use base Exporter;
		40
		41	$VERSION = 0.10;
		42
		43	@EXPORT = qw(async yield schedule terminate current);
		44	@EXPORT_OK = qw($current);
		45
		46	{
		47	my @async;
		48
		49	# this way of handling attributes simply is NOT scalable ;()
		50	sub import {
		51	Coro->export_to_level(1, @_);
		52	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		53	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		54	my ($package, $ref) = (shift, shift);
		55	my @attrs;
		56	for (@_) {
		57	if ($_ eq "Coro") {
		58	push @async, $ref;
		59	} else {
		60	push @attrs, $_;
		61	}
		62	}
		63	return $old ? $old->($package, $ref, @attrs) : @attrs;
		64	};
		65	}
		66
		67	sub INIT {
		68	&async(pop @async) while @async;
		69	}
		70	}
		71
		72	=item $main
		73
		74	This coroutine represents the main program.
		75
		76	=cut
		77
		78	our $main = new Coro;
		79
		80	=item $current (or as function: current)
		81
		82	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		83
		84	=cut
		85
		86	# maybe some other module used Coro::Specific before...
		87	if ($current) {
		88	$main->{specific} = $current->{specific};
		89	}
		90
		91	our $current = $main;
		92
		93	sub current() { $current }
		94
		95	=item $idle
		96
		97	The coroutine to switch to when no other coroutine is running. The default
		98	implementation prints "FATAL: deadlock detected" and exits.
		99
		100	=cut
		101
		102	# should be done using priorities :(
		103	our $idle = new Coro sub {
		104	print STDERR "FATAL: deadlock detected\n";
		105	exit(51);
		106	};
		107
		108	# we really need priorities...
		109	my @ready; # the ready queue. hehe, rather broken ;)
		110
		111	# static methods. not really.
		112
		113	=head2 STATIC METHODS
		114
		115	Static methods are actually functions that operate on the current process only.
34		116
35	=over 4	117	=over 4
36		118
37	=cut	119	=item async { ... } [@args...]
38		120
39	package Coro;	121	Create a new asynchronous process and return it's process object
		122	(usually unused). When the sub returns the new process is automatically
		123	terminated.
40		124
41	BEGIN {	125	# create a new coroutine that just prints its arguments
42	$VERSION = 0.03;	126	async {
		127	print "@_\n";
		128	} 1,2,3,4;
43		129
44	require XSLoader;	130	The coderef you submit MUST NOT be a closure that refers to variables
45	XSLoader::load Coro, $VERSION;	131	in an outer scope. This does NOT work. Pass arguments into it instead.
46	}
47		132
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	133	=cut
		134
		135	sub async(&@) {
		136	my $pid = new Coro @_;
		137	$pid->ready;
		138	$pid;
		139	}
		140
		141	=item schedule
		142
		143	Calls the scheduler. Please note that the current process will not be put
		144	into the ready queue, so calling this function usually means you will
		145	never be called again.
		146
		147	=cut
		148
		149	my $prev;
		150
		151	sub schedule {
		152	# should be done using priorities :(
		153	($prev, $current) = ($current, shift @ready \|\| $idle);
		154	Coro::State::transfer($prev, $current);
		155	}
		156
		157	=item yield
		158
		159	Yield to other processes. This function puts the current process into the
		160	ready queue and calls C<schedule>.
		161
		162	=cut
		163
		164	sub yield {
		165	$current->ready;
		166	&schedule;
		167	}
		168
		169	=item terminate
		170
		171	Terminates the current process.
		172
		173	Future versions of this function will allow result arguments.
		174
		175	=cut
		176
		177	sub terminate {
		178	$current->{_results} = [@_];
		179	&schedule;
		180	}
		181
		182	=back
		183
		184	# dynamic methods
		185
		186	=head2 PROCESS METHODS
		187
		188	These are the methods you can call on process objects.
		189
		190	=over 4
		191
		192	=item new Coro \&sub [, @args...]
		193
		194	Create a new process and return it. When the sub returns the process
		195	automatically terminates. To start the process you must first put it into
		196	the ready queue by calling the ready method.
		197
		198	The coderef you submit MUST NOT be a closure that refers to variables
		199	in an outer scope. This does NOT work. Pass arguments into it instead.
		200
		201	=cut
		202
		203	sub _newcoro {
		204	terminate &{+shift};
		205	}
59		206
60	sub new {	207	sub new {
61	my $class = $_[0];	208	my $class = shift;
62	my $proc = $_[1] \|\| sub { die "tried to transfer to an empty coroutine" };	209	bless {
63	bless _newprocess {	210	_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;	211	}, $class;
73	}	212	}
74		213
75	=item $prev->transfer($next)	214	=item $process->ready
76		215
77	Save the state of the current subroutine in $prev and switch to the	216	Put the current process into the ready queue.
78	coroutine saved in $next.
79		217
80	=cut	218	=cut
81		219
82	# I call the _transfer function from a perl function	220	sub ready {
83	# because that way perl saves all important things on	221	push @ready, $_[0];
84	# the stack.
85	sub transfer {
86	_transfer($_[0], $_[1]);
87	}	222	}
88		223
89	=item $error, $error_msg, $error_coro	224	=back
90		225
91	This coroutine will be called on fatal errors. C<$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	226	=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		227
105	1;	228	1;
106		229
107	=back	230	=head1 BUGS/LIMITATIONS
108		231
109	=head1 BUGS	232	- could be faster, especially when the core would introduce special
110		233	support for coroutines (like it does for threads).
111	This module has not yet been extensively tested.	234	- there is still a memleak on coroutine termination that I could not
		235	identify. Could be as small as a single SV.
		236	- this module is not well-tested.
		237	- if variables or arguments "disappear" (become undef) or become
		238	corrupted please contact the author so he cen iron out the
		239	remaining bugs.
		240	- this module is not thread-safe. You must only ever use this module from
		241	the same thread (this requirement might be loosened in the future to
		242	allow per-thread schedulers, but Coro::State does not yet allow this).
112		243
113	=head1 SEE ALSO	244	=head1 SEE ALSO
114		245
115	L<Coro::Process>, L<Coro::Signal>.	246	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		247	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
116		248
117	=head1 AUTHOR	249	=head1 AUTHOR
118		250
119	Marc Lehmann <pcg@goof.com>	251	Marc Lehmann <pcg@goof.com>
120	http://www.goof.com/pcg/marc/	252	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 1.20 by root, Sat Jul 21 18:21:45 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 1.20 by root, Sat Jul 21 18:21:45 2001 UTC