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

Comparing Coro/Coro.pm (file contents):
Revision 1.3 by root, Tue Jul 3 04:02:31 2001 UTC vs.
Revision 1.37 by root, Mon Sep 24 02:25:44 2001 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	Coro - create and 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	no warnings qw(uninitialized);
		38
		39	use Coro::State;
		40
		41	use base Exporter;
		42
		43	$VERSION = 0.5;
		44
		45	@EXPORT = qw(async cede schedule terminate current);
		46	%EXPORT_TAGS = (
		47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		48	);
		49	@EXPORT_OK = @{$EXPORT_TAGS{prio}};
		50
		51	{
		52	my @async;
		53	my $init;
		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, $ref;
		65	unless ($init++) {
		66	eval q{
		67	sub INIT {
		68	&async(pop @async) while @async;
		69	}
		70	};
		71	}
		72	} else {
		73	push @attrs, $_;
		74	}
		75	}
		76	return $old ? $old->($package, $ref, @attrs) : @attrs;
		77	};
		78	}
		79
		80	}
		81
		82	=item $main
		83
		84	This coroutine represents the main program.
		85
		86	=cut
		87
		88	our $main = new Coro;
		89
		90	=item $current (or as function: current)
		91
		92	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		93
		94	=cut
		95
		96	# maybe some other module used Coro::Specific before...
		97	if ($current) {
		98	$main->{specific} = $current->{specific};
		99	}
		100
		101	our $current = $main;
		102
		103	sub current() { $current }
		104
		105	=item $idle
		106
		107	The coroutine to switch to when no other coroutine is running. The default
		108	implementation prints "FATAL: deadlock detected" and exits.
		109
		110	=cut
		111
		112	# should be done using priorities :(
		113	our $idle = new Coro sub {
		114	print STDERR "FATAL: deadlock detected\n";
		115	exit(51);
		116	};
		117
		118	# this coroutine is necessary because a coroutine
		119	# cannot destroy itself.
		120	my @destroy;
		121	my $manager = new Coro sub {
		122	while() {
		123	# by overwriting the state object with the manager we destroy it
		124	# while still being able to schedule this coroutine (in case it has
		125	# been readied multiple times. this is harmless since the manager
		126	# can be called as many times as neccessary and will always
		127	# remove itself from the runqueue
		128	(pop @destroy)->{_coro_state} = $manager->{_coro_state} while @destroy;
		129	&schedule;
		130	}
		131	};
		132
		133	# static methods. not really.
		134
		135	=head2 STATIC METHODS
		136
		137	Static methods are actually functions that operate on the current process only.
32		138
33	=over 4	139	=over 4
34		140
35	=cut	141	=item async { ... } [@args...]
36		142
37	package Coro;	143	Create a new asynchronous process and return it's process object
		144	(usually unused). When the sub returns the new process is automatically
		145	terminated.
38		146
39	BEGIN {	147	# create a new coroutine that just prints its arguments
40	$VERSION = 0.01;	148	async {
		149	print "@_\n";
		150	} 1,2,3,4;
41		151
42	require XSLoader;	152	The coderef you submit MUST NOT be a closure that refers to variables
43	XSLoader::load Coro, $VERSION;	153	in an outer scope. This does NOT work. Pass arguments into it instead.
44	}
45		154
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	155	=cut
55		156
56	$main = $current = _newprocess {	157	sub async(&@) {
57	# never being called	158	my $pid = new Coro @_;
58	};	159	$manager->ready; # this ensures that the stack is cloned from the manager
		160	$pid->ready;
		161	$pid;
		162	}
59		163
60	=item $error, $error_msg, $error_coro	164	=item schedule
61		165
62	This coroutine will be called on fatal errors. C<$error_msg> and	166	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,	167	into the ready queue, so calling this function usually means you will
64	respectively.	168	never be called again.
65		169
66	=cut	170	=cut
67		171
68	$error_msg =	172	=item cede
69	$error_coro = undef;
70		173
71	$error = _newprocess {	174	"Cede" to other processes. This function puts the current process into the
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	175	ready queue and calls C<schedule>, which has the effect of giving up the
73	exit 250;	176	current "timeslice" to other coroutines of the same or higher priority.
74	};
75		177
76	=item $coro = new $coderef [, @args]
77
78	Create a new coroutine and return it. The first C<resume> call to this
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
83	=cut	178	=cut
		179
		180	=item terminate
		181
		182	Terminates the current process.
		183
		184	Future versions of this function will allow result arguments.
		185
		186	=cut
		187
		188	sub terminate {
		189	$current->cancel;
		190	&schedule;
		191	die; # NORETURN
		192	}
		193
		194	=back
		195
		196	# dynamic methods
		197
		198	=head2 PROCESS METHODS
		199
		200	These are the methods you can call on process objects.
		201
		202	=over 4
		203
		204	=item new Coro \&sub [, @args...]
		205
		206	Create a new process and return it. When the sub returns the process
		207	automatically terminates. To start the process you must first put it into
		208	the ready queue by calling the ready method.
		209
		210	The coderef you submit MUST NOT be a closure that refers to variables
		211	in an outer scope. This does NOT work. Pass arguments into it instead.
		212
		213	=cut
		214
		215	sub _newcoro {
		216	terminate &{+shift};
		217	}
84		218
85	sub new {	219	sub new {
86	my $class = $_[0];	220	my $class = shift;
87	my $proc = $_[1];	221	bless {
88	bless _newprocess {	222	_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;	223	}, $class;
97	}	224	}
98		225
99	=item $coro->resume	226	=item $process->ready
100		227
101	Resume execution at the given coroutine.	228	Put the current process into the ready queue.
102		229
103	=cut	230	=cut
104		231
105	my $prev;	232	=item $process->cancel
106		233
107	sub resume {	234	Like C<terminate>, but terminates the specified process instead.
108	$prev = $current; $current = $_[0];	235
109	_transfer($prev, $current);	236	=cut
		237
		238	sub cancel {
		239	push @destroy, $_[0];
		240	$manager->ready;
		241	&schedule if $current == $_[0];
110	}	242	}
		243
		244	=item $oldprio = $process->prio($newprio)
		245
		246	Sets the priority of the process. Higher priority processes get run before
		247	lower priority processes. Priorities are smalled signed integer (currently
		248	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import
		249	tag :prio to get then):
		250
		251	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		252	3 > 1 > 0 > -1 > -3 > -4
		253
		254	# set priority to HIGH
		255	current->prio(PRIO_HIGH);
		256
		257	The idle coroutine ($Coro::idle) always has a lower priority than any
		258	existing coroutine.
		259
		260	Changing the priority of the current process will take effect immediately,
		261	but changing the priority of processes in the ready queue (but not
		262	running) will only take effect after the next schedule (of that
		263	process). This is a bug that will be fixed in some future version.
		264
		265	=cut
		266
		267	sub prio {
		268	my $old = $_[0]{prio};
		269	$_[0]{prio} = $_[1] if @_ > 1;
		270	$old;
		271	}
		272
		273	=item $newprio = $process->nice($change)
		274
		275	Similar to C<prio>, but subtract the given value from the priority (i.e.
		276	higher values mean lower priority, just as in unix).
		277
		278	=cut
		279
		280	sub nice {
		281	$_[0]{prio} -= $_[1];
		282	}
		283
		284	=back
		285
		286	=cut
111		287
112	1;	288	1;
113		289
114	=back	290	=head1 BUGS/LIMITATIONS
115		291
116	=head1 BUGS	292	- you must make very sure that no coro is still active on global destruction.
117		293	very bad things might happen otherwise (usually segfaults).
118	This module has not yet been extensively tested.	294	- this module is not thread-safe. You must only ever use this module from
		295	the same thread (this requirement might be loosened in the future to
		296	allow per-thread schedulers, but Coro::State does not yet allow this).
119		297
120	=head1 SEE ALSO	298	=head1 SEE ALSO
121		299
122	L<Coro::Process>, L<Coro::Signal>.	300	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		301	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		302	L<Coro::Handle>, L<Coro::Socket>.
123		303
124	=head1 AUTHOR	304	=head1 AUTHOR
125		305
126	Marc Lehmann <pcg@goof.com>	306	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	307	http://www.goof.com/pcg/marc/

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Comparing Coro/Coro.pm (file contents): Revision 1.3 by root, Tue Jul 3 04:02:31 2001 UTC vs. Revision 1.37 by root, Mon Sep 24 02:25:44 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.3 by root, Tue Jul 3 04:02:31 2001 UTC vs.
Revision 1.37 by root, Mon Sep 24 02:25:44 2001 UTC