[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 1.21 by root, Sun Jul 22 03:24:10 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	WARNING: When using this module, make sure that, at program end, no
		34	coroutines are still running OR just call exit before falling off the
		35	end. The reason for this is that some coroutine of yours might have called
		36	into a C function, and falling off the end of main:: results in returning
		37	to that C function instead if to the main C interpreter.
		38
		39	=cut
		40
		41	package Coro;
		42
		43	use Coro::State;
		44
		45	use base Exporter;
		46
		47	$VERSION = 0.10;
		48
		49	@EXPORT = qw(async yield schedule terminate current);
		50	@EXPORT_OK = qw($current);
		51
		52	{
		53	my @async;
		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	} else {
		66	push @attrs, $_;
		67	}
		68	}
		69	return $old ? $old->($package, $ref, @attrs) : @attrs;
		70	};
		71	}
		72
		73	sub INIT {
		74	&async(pop @async) while @async;
		75	}
		76	}
		77
		78	=item $main
		79
		80	This coroutine represents the main program.
		81
		82	=cut
		83
		84	our $main = new Coro;
		85
		86	=item $current (or as function: current)
		87
		88	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		89
		90	=cut
		91
		92	# maybe some other module used Coro::Specific before...
		93	if ($current) {
		94	$main->{specific} = $current->{specific};
		95	}
		96
		97	our $current = $main;
		98
		99	sub current() { $current }
		100
		101	=item $idle
		102
		103	The coroutine to switch to when no other coroutine is running. The default
		104	implementation prints "FATAL: deadlock detected" and exits.
		105
		106	=cut
		107
		108	# should be done using priorities :(
		109	our $idle = new Coro sub {
		110	print STDERR "FATAL: deadlock detected\n";
		111	exit(51);
		112	};
		113
		114	# we really need priorities...
		115	my @ready; # the ready queue. hehe, rather broken ;)
		116
		117	# static methods. not really.
		118
		119	=head2 STATIC METHODS
		120
		121	Static methods are actually functions that operate on the current process only.
34		122
35	=over 4	123	=over 4
36		124
37	=cut	125	=item async { ... } [@args...]
38		126
39	package Coro;	127	Create a new asynchronous process and return it's process object
		128	(usually unused). When the sub returns the new process is automatically
		129	terminated.
40		130
41	BEGIN {	131	# create a new coroutine that just prints its arguments
42	$VERSION = 0.03;	132	async {
		133	print "@_\n";
		134	} 1,2,3,4;
43		135
44	require XSLoader;	136	The coderef you submit MUST NOT be a closure that refers to variables
45	XSLoader::load Coro, $VERSION;	137	in an outer scope. This does NOT work. Pass arguments into it instead.
46	}
47		138
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	139	=cut
		140
		141	sub async(&@) {
		142	my $pid = new Coro @_;
		143	$pid->ready;
		144	$pid;
		145	}
		146
		147	=item schedule
		148
		149	Calls the scheduler. Please note that the current process will not be put
		150	into the ready queue, so calling this function usually means you will
		151	never be called again.
		152
		153	=cut
		154
		155	my $prev;
		156
		157	sub schedule {
		158	# should be done using priorities :(
		159	($prev, $current) = ($current, shift @ready \|\| $idle);
		160	Coro::State::transfer($prev, $current);
		161	}
		162
		163	=item yield
		164
		165	Yield to other processes. This function puts the current process into the
		166	ready queue and calls C<schedule>.
		167
		168	=cut
		169
		170	sub yield {
		171	$current->ready;
		172	&schedule;
		173	}
		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->{_results} = [@_];
		185	delete $current->{_coro_state};
		186	&schedule;
		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	}
59		213
60	sub new {	214	sub new {
61	my $class = $_[0];	215	my $class = shift;
62	my $proc = $_[1] \|\| sub { die "tried to transfer to an empty coroutine" };	216	bless {
63	bless _newprocess {	217	_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;	218	}, $class;
73	}	219	}
74		220
75	=item $prev->transfer($next)	221	=item $process->ready
76		222
77	Save the state of the current subroutine in $prev and switch to the	223	Put the current process into the ready queue.
78	coroutine saved in $next.
79		224
80	=cut	225	=cut
81		226
82	# I call the _transfer function from a perl function	227	sub ready {
83	# because that way perl saves all important things on	228	push @ready, $_[0];
84	# the stack.
85	sub transfer {
86	_transfer($_[0], $_[1]);
87	}	229	}
88		230
89	=item $error, $error_msg, $error_coro	231	=back
90		232
91	This coroutine will be called on fatal errors. C<$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	233	=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		234
105	1;	235	1;
106		236
107	=back	237	=head1 BUGS/LIMITATIONS
108		238
109	=head1 BUGS	239	- could be faster, especially when the core would introduce special
110		240	support for coroutines (like it does for threads).
111	This module has not yet been extensively tested.	241	- there is still a memleak on coroutine termination that I could not
		242	identify. Could be as small as a single SV.
		243	- this module is not well-tested.
		244	- if variables or arguments "disappear" (become undef) or become
		245	corrupted please contact the author so he cen iron out the
		246	remaining bugs.
		247	- this module is not thread-safe. You must only ever use this module from
		248	the same thread (this requirement might be loosened in the future to
		249	allow per-thread schedulers, but Coro::State does not yet allow this).
112		250
113	=head1 SEE ALSO	251	=head1 SEE ALSO
114		252
115	L<Coro::Process>, L<Coro::Signal>.	253	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		254	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
116		255
117	=head1 AUTHOR	256	=head1 AUTHOR
118		257
119	Marc Lehmann <pcg@goof.com>	258	Marc Lehmann <pcg@goof.com>
120	http://www.goof.com/pcg/marc/	259	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 1.21 by root, Sun Jul 22 03:24:10 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 1.21 by root, Sun Jul 22 03:24:10 2001 UTC