[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 1.23 by root, Mon Jul 23 04:23:32 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	$VERSION = 0.10;
		42
		43	@EXPORT = qw(async cede schedule terminate current);
		44	@EXPORT_OK = qw($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	# 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.
32		116
33	=over 4	117	=over 4
34		118
35	=cut	119	=item async { ... } [@args...]
36		120
37	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.
38		124
39	BEGIN {	125	# create a new coroutine that just prints its arguments
40	$VERSION = 0.01;	126	async {
		127	print "@_\n";
		128	} 1,2,3,4;
41		129
42	require XSLoader;	130	The coderef you submit MUST NOT be a closure that refers to variables
43	XSLoader::load Coro, $VERSION;	131	in an outer scope. This does NOT work. Pass arguments into it instead.
44	}
45		132
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	133	=cut
55		134
56	$main = $current = _newprocess {	135	sub async(&@) {
57	# never being called	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 cede
		158
		159	"Cede" to other processes. This function puts the current process into the
		160	ready queue and calls C<schedule>, which has the effect of giving up the
		161	current "timeslice" to other coroutines of the same or higher priority.
		162
		163	=cut
		164
		165	sub cede {
		166	$current->ready;
		167	&schedule;
		168	}
		169
		170	=item terminate
		171
		172	Terminates the current process.
		173
		174	Future versions of this function will allow result arguments.
		175
		176	=cut
		177
		178	# this coroutine is necessary because a coroutine
		179	# cannot destroy itself.
		180	my @destroy;
		181	my $terminate = new Coro sub {
		182	while() {
		183	delete ((pop @destroy)->{_coro_state}) while @destroy;
		184	&schedule;
		185	}
58	};	186	};
59		187
60	=item $error, $error_msg, $error_coro	188	sub terminate {
		189	push @destroy, $current;
		190	$terminate->ready;
		191	&schedule;
		192	# NORETURN
		193	}
61		194
62	This coroutine will be called on fatal errors. C<$error_msg> and	195	=back
63	C<$error_coro> return the error message and the error-causing coroutine,
64	respectively.
65		196
66	=cut	197	# dynamic methods
67		198
68	$error_msg =	199	=head2 PROCESS METHODS
69	$error_coro = undef;
70		200
71	$error = _newprocess {	201	These are the methods you can call on process objects.
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";
73	exit 250;
74	};
75		202
76	=item $coro = new $coderef [, @args]	203	=over 4
77		204
78	Create a new coroutine and return it. The first C<resume> call to this	205	=item new Coro \&sub [, @args...]
79	coroutine will start execution at the given coderef. If it returns it
80	should return a coroutine to switch to. If, after returning, the coroutine
81	is C<resume>d again it starts execution again at the givne coderef.
82		206
		207	Create a new process and return it. When the sub returns the process
		208	automatically terminates. To start the process you must first put it into
		209	the ready queue by calling the ready method.
		210
		211	The coderef you submit MUST NOT be a closure that refers to variables
		212	in an outer scope. This does NOT work. Pass arguments into it instead.
		213
83	=cut	214	=cut
		215
		216	sub _newcoro {
		217	terminate &{+shift};
		218	}
84		219
85	sub new {	220	sub new {
86	my $class = $_[0];	221	my $class = shift;
87	my $proc = $_[1];	222	bless {
88	bless _newprocess {	223	_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;	224	}, $class;
97	}	225	}
98		226
99	=item $coro->resume	227	=item $process->ready
100		228
101	Resume execution at the given coroutine.	229	Put the current process into the ready queue.
102		230
103	=cut	231	=cut
104		232
105	my $prev;	233	sub ready {
106		234	push @ready, $_[0];
107	sub resume {
108	$prev = $current; $current = $_[0];
109	_transfer($prev, $current);
110	}	235	}
		236
		237	=back
		238
		239	=cut
111		240
112	1;	241	1;
113		242
114	=back	243	=head1 BUGS/LIMITATIONS
115		244
116	=head1 BUGS	245	- could be faster, especially when the core would introduce special
117		246	support for coroutines (like it does for threads).
118	This module has not yet been extensively tested.	247	- there is still a memleak on coroutine termination that I could not
		248	identify. Could be as small as a single SV.
		249	- this module is not well-tested.
		250	- if variables or arguments "disappear" (become undef) or become
		251	corrupted please contact the author so he cen iron out the
		252	remaining bugs.
		253	- this module is not thread-safe. You must only ever use this module from
		254	the same thread (this requirement might be loosened in the future to
		255	allow per-thread schedulers, but Coro::State does not yet allow this).
119		256
120	=head1 SEE ALSO	257	=head1 SEE ALSO
121		258
122	L<Coro::Process>, L<Coro::Signal>.	259	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		260	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
123		261
124	=head1 AUTHOR	262	=head1 AUTHOR
125		263
126	Marc Lehmann <pcg@goof.com>	264	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	265	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 1.23 by root, Mon Jul 23 04:23:32 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 1.23 by root, Mon Jul 23 04:23:32 2001 UTC