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

Comparing Coro/Coro.pm (file contents):
Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs.
Revision 1.25 by root, Wed Jul 25 21:12:57 2001 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	Coro - create an manage 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	$Coro::main->resume;
12	print "in coroutine again, switching back\n";
13	$Coro::main->resume;
14	};	11	};
15		12
16	print "in main, switching to coroutine\n";	13	# alternatively create an async process like this:
17	$new->resume;	14
18	print "back in main, switch to coroutine again\n";	15	sub some_func : Coro {
19	$new->resume;	16	# some more async code
20	print "back in main\n";	17	}
		18
		19	cede;
21		20
22	=head1 DESCRIPTION	21	=head1 DESCRIPTION
23		22
24	This module implements coroutines. Coroutines, similar to continuations,	23	This module collection manages coroutines. Coroutines are similar to
25	allow you to run more than one "thread of execution" in parallel. Unlike	24	Threads but don't run in parallel.
26	threads this, only voluntary switching is used so locking problems are
27	greatly reduced.
28		25
29	Although this is the "main" module of the Coro family it provides only	26	This module is still experimental, see the BUGS section below.
30	low-level functionality. See L<Coro::Process> and related modules for a	27
31	more useful process abstraction including scheduling.	28	In this module, coroutines are defined as "callchain + lexical variables
		29	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
		30	callchain, it's own set of lexicals and it's own set of perl's most
		31	important global variables.
		32
		33	=cut
		34
		35	package Coro;
		36
		37	use Coro::State;
		38
		39	use base Exporter;
		40
		41	$VERSION = 0.12;
		42
		43	@EXPORT = qw(async cede schedule terminate current);
		44	@EXPORT_OK = qw($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	# this coroutine is necessary because a coroutine
		109	# cannot destroy itself.
		110	my @destroy;
		111	my $manager = new Coro sub {
		112	while() {
		113	delete ((pop @destroy)->{_coro_state}) while @destroy;
		114	&schedule;
		115	}
		116	};
		117
		118	# we really need priorities...
		119	my @ready; # the ready queue. hehe, rather broken ;)
		120
		121	# static methods. not really.
		122
		123	=head2 STATIC METHODS
		124
		125	Static methods are actually functions that operate on the current process only.
32		126
33	=over 4	127	=over 4
34		128
35	=cut	129	=item async { ... } [@args...]
36		130
37	package Coro;	131	Create a new asynchronous process and return it's process object
		132	(usually unused). When the sub returns the new process is automatically
		133	terminated.
38		134
39	BEGIN {	135	# create a new coroutine that just prints its arguments
40	$VERSION = 0.01;	136	async {
		137	print "@_\n";
		138	} 1,2,3,4;
41		139
42	require XSLoader;	140	The coderef you submit MUST NOT be a closure that refers to variables
43	XSLoader::load Coro, $VERSION;	141	in an outer scope. This does NOT work. Pass arguments into it instead.
44	}
45		142
46	=item $main
47
48	This coroutine represents the main program.
49
50	=item $current
51
52	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
53
54	=cut	143	=cut
55		144
56	$main = $current = _newprocess {	145	sub async(&@) {
57	# never being called	146	my $pid = new Coro @_;
58	};	147	$manager->ready; # this ensures that the stack is cloned from the manager
		148	$pid->ready;
		149	$pid;
		150	}
59		151
60	=item $error, $error_msg, $error_coro	152	=item schedule
61		153
62	This coroutine will be called on fatal errors. C<$error_msg> and	154	Calls the scheduler. Please note that the current process will not be put
63	C<$error_coro> return the error message and the error-causing coroutine,	155	into the ready queue, so calling this function usually means you will
64	respectively.	156	never be called again.
65		157
66	=cut	158	=cut
67		159
68	$error_msg =	160	my $prev;
69	$error_coro = undef;
70		161
71	$error = _newprocess {	162	sub schedule {
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	163	# should be done using priorities :(
73	exit 250;	164	($prev, $current) = ($current, shift @ready \|\| $idle);
74	};	165	Coro::State::transfer($prev, $current);
		166	}
75		167
76	=item $coro = new $coderef [, @args]	168	=item cede
77		169
78	Create a new coroutine and return it. The first C<resume> call to this	170	"Cede" to other processes. This function puts the current process into the
79	coroutine will start execution at the given coderef. If it returns it	171	ready queue and calls C<schedule>, which has the effect of giving up the
80	should return a coroutine to switch to. If, after returning, the coroutine	172	current "timeslice" to other coroutines of the same or higher priority.
81	is C<resume>d again it starts execution again at the givne coderef.
82		173
83	=cut	174	=cut
		175
		176	sub cede {
		177	$current->ready;
		178	&schedule;
		179	}
		180
		181	=item terminate
		182
		183	Terminates the current process.
		184
		185	Future versions of this function will allow result arguments.
		186
		187	=cut
		188
		189	sub terminate {
		190	push @destroy, $current;
		191	$manager->ready;
		192	&schedule;
		193	# NORETURN
		194	}
		195
		196	=back
		197
		198	# dynamic methods
		199
		200	=head2 PROCESS METHODS
		201
		202	These are the methods you can call on process objects.
		203
		204	=over 4
		205
		206	=item new Coro \&sub [, @args...]
		207
		208	Create a new process and return it. When the sub returns the process
		209	automatically terminates. To start the process you must first put it into
		210	the ready queue by calling the ready method.
		211
		212	The coderef you submit MUST NOT be a closure that refers to variables
		213	in an outer scope. This does NOT work. Pass arguments into it instead.
		214
		215	=cut
		216
		217	sub _newcoro {
		218	terminate &{+shift};
		219	}
84		220
85	sub new {	221	sub new {
86	my $class = $_[0];	222	my $class = shift;
87	my $proc = $_[1];	223	bless {
88	bless _newprocess {	224	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
89	do {
90	eval { &$proc->resume };
91	if ($@) {
92	($error_msg, $error_coro) = ($@, $current);
93	$error->resume;
94	}
95	} while ();
96	}, $class;	225	}, $class;
97	}	226	}
98		227
99	=item $coro->resume	228	=item $process->ready
100		229
101	Resume execution at the given coroutine.	230	Put the current process into the ready queue.
102		231
103	=cut	232	=cut
104		233
105	my $prev;	234	sub ready {
106		235	push @ready, $_[0];
107	sub resume {
108	$prev = $current; $current = $_[0];
109	_transfer($prev, $current);
110	}	236	}
		237
		238	=back
		239
		240	=cut
111		241
112	1;	242	1;
113		243
114	=back	244	=head1 BUGS/LIMITATIONS
115		245
116	=head1 BUGS	246	- could be faster, especially when the core would introduce special
117		247	support for coroutines (like it does for threads).
118	This module has not yet been extensively tested.	248	- there is still a memleak on coroutine termination that I could not
		249	identify. Could be as small as a single SV.
		250	- this module is not well-tested.
		251	- if variables or arguments "disappear" (become undef) or become
		252	corrupted please contact the author so he cen iron out the
		253	remaining bugs.
		254	- this module is not thread-safe. You must only ever use this module from
		255	the same thread (this requirement might be loosened in the future to
		256	allow per-thread schedulers, but Coro::State does not yet allow this).
119		257
120	=head1 SEE ALSO	258	=head1 SEE ALSO
121		259
122	L<Coro::Process>, L<Coro::Signal>.	260	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		261	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		262	L<Coro::L<Coro::Handle>, L<Coro::Socket>.
123		263
124	=head1 AUTHOR	264	=head1 AUTHOR
125		265
126	Marc Lehmann <pcg@goof.com>	266	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	267	http://www.goof.com/pcg/marc/

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Comparing Coro/Coro.pm (file contents): Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs. Revision 1.25 by root, Wed Jul 25 21:12:57 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs.
Revision 1.25 by root, Wed Jul 25 21:12:57 2001 UTC