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

Comparing Coro/Coro.pm (file contents):
Revision 1.1 by root, Tue Jul 3 02:53:34 2001 UTC vs.
Revision 1.22 by root, Mon Jul 23 02:14:19 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	async {
		10	# some asynchronous thread of execution
		11	};
		12
		13	# alternatively create an async process like this:
		14
		15	sub some_func : Coro {
		16	# some more async code
		17	}
		18
		19	cede;
		20
9	=head1 DESCRIPTION	21	=head1 DESCRIPTION
10		22
		23	This module collection manages coroutines. Coroutines are similar to
		24	Threads but don't run in parallel.
		25
		26	This module is still experimental, see the BUGS section below.
		27
		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	WARNING: Unless you really know what you are doing, do NOT do context
		40	switches inside callbacks from the XS level. The reason for this is
		41	similar to the reason above: A callback calls a perl function, this
		42	perl function does a context switch, some other callback is called, the
		43	original function returns from it - to what? To the wrong XS function,
		44	with totally different return values. Unfortunately, this includes
		45	callbacks done by perl itself (tie'd variables!).
		46
		47	The only workaround for this is to do coroutines on C level.
		48
		49	=cut
		50
		51	package Coro;
		52
		53	use Coro::State;
		54
		55	use base Exporter;
		56
		57	$VERSION = 0.10;
		58
		59	@EXPORT = qw(async cede schedule terminate current);
		60	@EXPORT_OK = qw($current);
		61
		62	{
		63	my @async;
		64
		65	# this way of handling attributes simply is NOT scalable ;()
		66	sub import {
		67	Coro->export_to_level(1, @_);
		68	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		69	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		70	my ($package, $ref) = (shift, shift);
		71	my @attrs;
		72	for (@_) {
		73	if ($_ eq "Coro") {
		74	push @async, $ref;
		75	} else {
		76	push @attrs, $_;
		77	}
		78	}
		79	return $old ? $old->($package, $ref, @attrs) : @attrs;
		80	};
		81	}
		82
		83	sub INIT {
		84	&async(pop @async) while @async;
		85	}
		86	}
		87
		88	=item $main
		89
		90	This coroutine represents the main program.
		91
		92	=cut
		93
		94	our $main = new Coro;
		95
		96	=item $current (or as function: current)
		97
		98	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		99
		100	=cut
		101
		102	# maybe some other module used Coro::Specific before...
		103	if ($current) {
		104	$main->{specific} = $current->{specific};
		105	}
		106
		107	our $current = $main;
		108
		109	sub current() { $current }
		110
		111	=item $idle
		112
		113	The coroutine to switch to when no other coroutine is running. The default
		114	implementation prints "FATAL: deadlock detected" and exits.
		115
		116	=cut
		117
		118	# should be done using priorities :(
		119	our $idle = new Coro sub {
		120	print STDERR "FATAL: deadlock detected\n";
		121	exit(51);
		122	};
		123
		124	# we really need priorities...
		125	my @ready; # the ready queue. hehe, rather broken ;)
		126
		127	# static methods. not really.
		128
		129	=head2 STATIC METHODS
		130
		131	Static methods are actually functions that operate on the current process only.
		132
11	=over 4	133	=over 4
12		134
13	=cut	135	=item async { ... } [@args...]
14		136
15	package Coro;	137	Create a new asynchronous process and return it's process object
		138	(usually unused). When the sub returns the new process is automatically
		139	terminated.
16		140
17	BEGIN {	141	# create a new coroutine that just prints its arguments
18	$VERSION = 0.01;	142	async {
		143	print "@_\n";
		144	} 1,2,3,4;
19		145
20	require XSLoader;	146	The coderef you submit MUST NOT be a closure that refers to variables
21	XSLoader::load Coro, $VERSION;	147	in an outer scope. This does NOT work. Pass arguments into it instead.
22	}
23		148
24	=item $main
25
26	This coroutine represents the main program.
27
28	=item $current
29
30	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
31
32	=cut	149	=cut
33		150
34	$main = $current = _newprocess {	151	sub async(&@) {
35	# never being called	152	my $pid = new Coro @_;
36	};	153	$pid->ready;
		154	$pid;
		155	}
37		156
38	=item $error, $error_msg, $error_coro	157	=item schedule
39		158
40	This coroutine will be called on fatal errors. C<$error_msg> and	159	Calls the scheduler. Please note that the current process will not be put
41	C<$error_coro> return the error message and the error-causing coroutine,	160	into the ready queue, so calling this function usually means you will
42	respectively.	161	never be called again.
43		162
44	=cut	163	=cut
45		164
46	$error_msg =	165	my $prev;
47	$error_coro = undef;
48		166
49	$error = _newprocess {	167	sub schedule {
50	print STDERR "FATAL: $error_msg, program aborted\n";	168	# should be done using priorities :(
51	exit 250;	169	($prev, $current) = ($current, shift @ready \|\| $idle);
52	};	170	Coro::State::transfer($prev, $current);
		171	}
53		172
54	=item $coro = new $coderef [, @args]	173	=item cede
55		174
56	Create a new coroutine and return it. The first C<resume> call to this	175	"Cede" to other processes. This function puts the current process into the
57	coroutine will start execution at the given coderef. If it returns it	176	ready queue and calls C<schedule>, which has the effect of giving up the
58	should return a coroutine to switch to. If, after returning, the coroutine	177	current "timeslice" to other coroutines of the same or higher priority.
59	is C<resume>d again it starts execution again at the givne coderef.
60		178
61	=cut	179	=cut
		180
		181	sub cede {
		182	$current->ready;
		183	&schedule;
		184	}
		185
		186	=item terminate
		187
		188	Terminates the current process.
		189
		190	Future versions of this function will allow result arguments.
		191
		192	=cut
		193
		194	sub terminate {
		195	my $self = $current;
		196	$self->{_results} = [@_];
		197	$current = shift @ready \|\| $idle;
		198	Coro::State::transfer(delete $self->{_coro_state}, $current);
		199	# cannot return
		200	die;
		201	}
		202
		203	=back
		204
		205	# dynamic methods
		206
		207	=head2 PROCESS METHODS
		208
		209	These are the methods you can call on process objects.
		210
		211	=over 4
		212
		213	=item new Coro \&sub [, @args...]
		214
		215	Create a new process and return it. When the sub returns the process
		216	automatically terminates. To start the process you must first put it into
		217	the ready queue by calling the ready method.
		218
		219	The coderef you submit MUST NOT be a closure that refers to variables
		220	in an outer scope. This does NOT work. Pass arguments into it instead.
		221
		222	=cut
		223
		224	sub _newcoro {
		225	terminate &{+shift};
		226	}
62		227
63	sub new {	228	sub new {
64	my $class = $_[0];	229	my $class = shift;
65	my $proc = $_[1];	230	bless {
66	bless _newprocess {	231	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
67	do {
68	eval { &$proc->resume };
69	if ($@) {
70	($error_msg, $error_coro) = ($@, $current);
71	$error->resume;
72	}
73	} while ();
74	}, $class;	232	}, $class;
75	}	233	}
76		234
77	=item $coro->resume	235	=item $process->ready
78		236
79	Resume execution at the given coroutine.	237	Put the current process into the ready queue.
80		238
81	=cut	239	=cut
82		240
83	my $prev;	241	sub ready {
84		242	push @ready, $_[0];
85	sub resume {
86	$prev = $current; $current = $_[0];
87	_transfer($prev, $current);
88	}	243	}
		244
		245	=back
		246
		247	=cut
89		248
90	1;	249	1;
91		250
92	=back	251	=head1 BUGS/LIMITATIONS
93		252
94	=head1 BUGS	253	- could be faster, especially when the core would introduce special
		254	support for coroutines (like it does for threads).
		255	- there is still a memleak on coroutine termination that I could not
		256	identify. Could be as small as a single SV.
		257	- this module is not well-tested.
		258	- if variables or arguments "disappear" (become undef) or become
		259	corrupted please contact the author so he cen iron out the
		260	remaining bugs.
		261	- this module is not thread-safe. You must only ever use this module from
		262	the same thread (this requirement might be loosened in the future to
		263	allow per-thread schedulers, but Coro::State does not yet allow this).
95		264
96	This module has not yet been extensively tested.	265	=head1 SEE ALSO
		266
		267	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		268	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
97		269
98	=head1 AUTHOR	270	=head1 AUTHOR
99		271
100	Marc Lehmann <pcg@goof.com>	272	Marc Lehmann <pcg@goof.com>
101	http://www.goof.com/pcg/marc/	273	http://www.goof.com/pcg/marc/

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Comparing Coro/Coro.pm (file contents): Revision 1.1 by root, Tue Jul 3 02:53:34 2001 UTC vs. Revision 1.22 by root, Mon Jul 23 02:14:19 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.1 by root, Tue Jul 3 02:53:34 2001 UTC vs.
Revision 1.22 by root, Mon Jul 23 02:14:19 2001 UTC