[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 1.29 by root, Sat Aug 11 00:37:31 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	$VERSION = 0.45;
		42
		43	@EXPORT = qw(async cede schedule terminate current);
		44	@EXPORT_OK = qw($current);
		45
		46	{
		47	my @async;
		48	my $init;
		49
		50	# this way of handling attributes simply is NOT scalable ;()
		51	sub import {
		52	Coro->export_to_level(1, @_);
		53	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		54	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		55	my ($package, $ref) = (shift, shift);
		56	my @attrs;
		57	for (@_) {
		58	if ($_ eq "Coro") {
		59	push @async, $ref;
		60	unless ($init++) {
		61	eval q{
		62	sub INIT {
		63	&async(pop @async) while @async;
		64	}
		65	};
		66	}
		67	} else {
		68	push @attrs, $_;
		69	}
		70	}
		71	return $old ? $old->($package, $ref, @attrs) : @attrs;
		72	};
		73	}
		74
		75	}
		76
		77	=item $main
		78
		79	This coroutine represents the main program.
		80
		81	=cut
		82
		83	our $main = new Coro;
		84
		85	=item $current (or as function: current)
		86
		87	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		88
		89	=cut
		90
		91	# maybe some other module used Coro::Specific before...
		92	if ($current) {
		93	$main->{specific} = $current->{specific};
		94	}
		95
		96	our $current = $main;
		97
		98	sub current() { $current }
		99
		100	=item $idle
		101
		102	The coroutine to switch to when no other coroutine is running. The default
		103	implementation prints "FATAL: deadlock detected" and exits.
		104
		105	=cut
		106
		107	# should be done using priorities :(
		108	our $idle = new Coro sub {
		109	print STDERR "FATAL: deadlock detected\n";
		110	exit(51);
		111	};
		112
		113	# this coroutine is necessary because a coroutine
		114	# cannot destroy itself.
		115	my @destroy;
		116	my $manager = new Coro sub {
		117	while() {
		118	delete ((pop @destroy)->{_coro_state}) while @destroy;
		119	&schedule;
		120	}
		121	};
		122
		123	# we really need priorities...
		124	my @ready; # the ready queue. hehe, rather broken ;)
		125
		126	# static methods. not really.
		127
		128	=head2 STATIC METHODS
		129
		130	Static methods are actually functions that operate on the current process only.
32		131
33	=over 4	132	=over 4
34		133
35	=cut	134	=item async { ... } [@args...]
36		135
37	package Coro;	136	Create a new asynchronous process and return it's process object
		137	(usually unused). When the sub returns the new process is automatically
		138	terminated.
38		139
39	BEGIN {	140	# create a new coroutine that just prints its arguments
40	$VERSION = 0.01;	141	async {
		142	print "@_\n";
		143	} 1,2,3,4;
41		144
42	require XSLoader;	145	The coderef you submit MUST NOT be a closure that refers to variables
43	XSLoader::load Coro, $VERSION;	146	in an outer scope. This does NOT work. Pass arguments into it instead.
44	}
45		147
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	148	=cut
55		149
56	$main = $current = _newprocess {	150	sub async(&@) {
57	# never being called	151	my $pid = new Coro @_;
58	};	152	$manager->ready; # this ensures that the stack is cloned from the manager
		153	$pid->ready;
		154	$pid;
		155	}
59		156
60	=item $error, $error_msg, $error_coro	157	=item schedule
61		158
62	This coroutine will be called on fatal errors. C<$error_msg> and	159	Calls the scheduler. Please note that the current process will not be put
63	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
64	respectively.	161	never be called again.
65		162
66	=cut	163	=cut
67		164
68	$error_msg =	165	my $prev;
69	$error_coro = undef;
70		166
71	$error = _newprocess {	167	sub schedule {
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	168	# should be done using priorities :(
73	exit 250;	169	($prev, $current) = ($current, shift @ready \|\| $idle);
74	};	170	Coro::State::transfer($prev, $current);
		171	}
75		172
76	=item $coro = new $coderef [, @args]	173	=item cede
77		174
78	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
79	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
80	should return a coroutine to switch to. If, after returning, the coroutine	177	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		178
83	=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	$current->cancel;
		196	&schedule;
		197	die; # NORETURN
		198	}
		199
		200	=back
		201
		202	# dynamic methods
		203
		204	=head2 PROCESS METHODS
		205
		206	These are the methods you can call on process objects.
		207
		208	=over 4
		209
		210	=item new Coro \&sub [, @args...]
		211
		212	Create a new process and return it. When the sub returns the process
		213	automatically terminates. To start the process you must first put it into
		214	the ready queue by calling the ready method.
		215
		216	The coderef you submit MUST NOT be a closure that refers to variables
		217	in an outer scope. This does NOT work. Pass arguments into it instead.
		218
		219	=cut
		220
		221	sub _newcoro {
		222	terminate &{+shift};
		223	}
84		224
85	sub new {	225	sub new {
86	my $class = $_[0];	226	my $class = shift;
87	my $proc = $_[1];	227	bless {
88	bless _newprocess {	228	_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;	229	}, $class;
97	}	230	}
98		231
99	=item $coro->resume	232	=item $process->ready
100		233
101	Resume execution at the given coroutine.	234	Put the current process into the ready queue.
102		235
103	=cut	236	=cut
104		237
105	my $prev;	238	sub ready {
106		239	push @ready, $_[0];
107	sub resume {
108	$prev = $current; $current = $_[0];
109	_transfer($prev, $current);
110	}	240	}
		241
		242	=item $process->cancel
		243
		244	Like C<terminate>, but terminates the specified process instead.
		245
		246	=cut
		247
		248	sub cancel {
		249	push @destroy, $_[0];
		250	$manager->ready;
		251	}
		252
		253	=back
		254
		255	=cut
111		256
112	1;	257	1;
113		258
114	=back	259	=head1 BUGS/LIMITATIONS
115		260
116	=head1 BUGS	261	- could be faster, especially when the core would introduce special
117		262	support for coroutines (like it does for threads).
118	This module has not yet been extensively tested.	263	- there is still a memleak on coroutine termination that I could not
		264	identify. Could be as small as a single SV.
		265	- this module is not well-tested.
		266	- if variables or arguments "disappear" (become undef) or become
		267	corrupted please contact the author so he cen iron out the
		268	remaining bugs.
		269	- this module is not thread-safe. You must only ever use this module from
		270	the same thread (this requirement might be loosened in the future to
		271	allow per-thread schedulers, but Coro::State does not yet allow this).
119		272
120	=head1 SEE ALSO	273	=head1 SEE ALSO
121		274
122	L<Coro::Process>, L<Coro::Signal>.	275	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		276	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		277	L<Coro::Handle>, L<Coro::Socket>.
123		278
124	=head1 AUTHOR	279	=head1 AUTHOR
125		280
126	Marc Lehmann <pcg@goof.com>	281	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	282	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 1.29 by root, Sat Aug 11 00:37:31 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 1.29 by root, Sat Aug 11 00:37:31 2001 UTC