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

Comparing Coro/Coro.pm (file contents):
Revision 1.4 by root, Tue Jul 3 05:05:45 2001 UTC vs.
Revision 1.39 by root, Tue Oct 9 00:39:08 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	$VERSION = 0.51;
		44
		45	@EXPORT = qw(async cede schedule terminate current);
		46	%EXPORT_TAGS = (
		47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		48	);
		49	@EXPORT_OK = @{$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;
		122	$manager = new Coro sub {
		123	while() {
		124	# by overwriting the state object with the manager we destroy it
		125	# while still being able to schedule this coroutine (in case it has
		126	# been readied multiple times. this is harmless since the manager
		127	# can be called as many times as neccessary and will always
		128	# remove itself from the runqueue
		129	(pop @destroy)->{_coro_state} = $manager->{_coro_state} while @destroy;
		130	&schedule;
		131	}
		132	};
		133
		134	# static methods. not really.
		135
		136	=head2 STATIC METHODS
		137
		138	Static methods are actually functions that operate on the current process only.
32		139
33	=over 4	140	=over 4
34		141
35	=cut	142	=item async { ... } [@args...]
36		143
37	package Coro;	144	Create a new asynchronous process and return it's process object
		145	(usually unused). When the sub returns the new process is automatically
		146	terminated.
38		147
39	BEGIN {	148	# create a new coroutine that just prints its arguments
40	$VERSION = 0.01;	149	async {
		150	print "@_\n";
		151	} 1,2,3,4;
41		152
42	require XSLoader;	153	The coderef you submit MUST NOT be a closure that refers to variables
43	XSLoader::load Coro, $VERSION;	154	in an outer scope. This does NOT work. Pass arguments into it instead.
44	}
45		155
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	156	=cut
55		157
56	$main = $current = _newprocess {	158	sub async(&@) {
57	# never being called	159	my $pid = new Coro @_;
58	};	160	$manager->ready; # this ensures that the stack is cloned from the manager
		161	$pid->ready;
		162	$pid;
		163	}
59		164
60	=item $error, $error_msg, $error_coro	165	=item schedule
61		166
62	This coroutine will be called on fatal errors. C<$error_msg> and	167	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,	168	into the ready queue, so calling this function usually means you will
64	respectively.	169	never be called again.
65		170
66	=cut	171	=cut
67		172
68	$error_msg =	173	=item cede
69	$error_coro = undef;
70		174
71	$error = _newprocess {	175	"Cede" to other processes. This function puts the current process into the
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	176	ready queue and calls C<schedule>, which has the effect of giving up the
73	exit 250;	177	current "timeslice" to other coroutines of the same or higher priority.
74	};
75		178
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	179	=cut
		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	$current->cancel;
		191	&schedule;
		192	die; # NORETURN
		193	}
		194
		195	=back
		196
		197	# dynamic methods
		198
		199	=head2 PROCESS METHODS
		200
		201	These are the methods you can call on process objects.
		202
		203	=over 4
		204
		205	=item new Coro \&sub [, @args...]
		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
		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 (1);
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 given process into the ready queue.
102		230
103	=cut	231	=cut
104		232
105	my $prev;	233	=item $process->cancel
106		234
107	sub resume {	235	Like C<terminate>, but terminates the specified process instead.
108	$prev = $current; $current = $_[0];	236
109	_transfer($prev, $current);	237	=cut
		238
		239	sub cancel {
		240	push @destroy, $_[0];
		241	$manager->ready;
		242	&schedule if $current == $_[0];
110	}	243	}
		244
		245	=item $oldprio = $process->prio($newprio)
		246
		247	Sets the priority of the process. Higher priority processes get run before
		248	lower priority processes. Priorities are smalled signed integer (currently
		249	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import
		250	tag :prio to get then):
		251
		252	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		253	3 > 1 > 0 > -1 > -3 > -4
		254
		255	# set priority to HIGH
		256	current->prio(PRIO_HIGH);
		257
		258	The idle coroutine ($Coro::idle) always has a lower priority than any
		259	existing coroutine.
		260
		261	Changing the priority of the current process will take effect immediately,
		262	but changing the priority of processes in the ready queue (but not
		263	running) will only take effect after the next schedule (of that
		264	process). This is a bug that will be fixed in some future version.
		265
		266	=cut
		267
		268	sub prio {
		269	my $old = $_[0]{prio};
		270	$_[0]{prio} = $_[1] if @_ > 1;
		271	$old;
		272	}
		273
		274	=item $newprio = $process->nice($change)
		275
		276	Similar to C<prio>, but subtract the given value from the priority (i.e.
		277	higher values mean lower priority, just as in unix).
		278
		279	=cut
		280
		281	sub nice {
		282	$_[0]{prio} -= $_[1];
		283	}
		284
		285	=back
		286
		287	=cut
111		288
112	1;	289	1;
113		290
114	=back	291	=head1 BUGS/LIMITATIONS
115		292
116	=head1 BUGS	293	- you must make very sure that no coro is still active on global destruction.
117		294	very bad things might happen otherwise (usually segfaults).
118	This module has not yet been extensively tested.	295	- this module is not thread-safe. You must only ever use this module from
		296	the same thread (this requirement might be loosened in the future to
		297	allow per-thread schedulers, but Coro::State does not yet allow this).
119		298
120	=head1 SEE ALSO	299	=head1 SEE ALSO
121		300
122	L<Coro::Process>, L<Coro::Signal>.	301	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		302	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		303	L<Coro::Handle>, L<Coro::Socket>.
123		304
124	=head1 AUTHOR	305	=head1 AUTHOR
125		306
126	Marc Lehmann <pcg@goof.com>	307	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	308	http://www.goof.com/pcg/marc/

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Comparing Coro/Coro.pm (file contents): Revision 1.4 by root, Tue Jul 3 05:05:45 2001 UTC vs. Revision 1.39 by root, Tue Oct 9 00:39:08 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.4 by root, Tue Jul 3 05:05:45 2001 UTC vs.
Revision 1.39 by root, Tue Oct 9 00:39:08 2001 UTC