[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 1.58 by pcg, Fri Feb 13 23:17:41 2004 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	In this module, coroutines are defined as "callchain + lexical variables
30	low-level functionality. See L<Coro::Process> and related modules for a	27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
31	more useful process abstraction including scheduling.	28	callchain, it's own set of lexicals and it's own set of perl's most
		29	important global variables.
		30
		31	=cut
		32
		33	package Coro;
		34
		35	BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") }
		36
		37	use Coro::State;
		38
		39	use vars qw($idle $main $current);
		40
		41	use base Exporter;
		42
		43	$VERSION = 0.95;
		44
		45	@EXPORT = qw(async cede schedule terminate current);
		46	%EXPORT_TAGS = (
		47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		48	);
		49	@EXPORT_OK = @{$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	}
32		81
33	=over 4	82	=over 4
34		83
35	=cut
36
37	package Coro;
38
39	BEGIN {
40	$VERSION = 0.01;
41
42	require XSLoader;
43	XSLoader::load Coro, $VERSION;
44	}
45
46	=item $main	84	=item $main
47		85
48	This coroutine represents the main program.	86	This coroutine represents the main program.
49		87
50	=item $current	88	=cut
		89
		90	$main = new Coro;
		91
		92	=item $current (or as function: current)
51		93
52	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	94	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
53		95
54	=cut	96	=cut
55		97
56	$main = $current = _newprocess {	98	# maybe some other module used Coro::Specific before...
57	# never being called	99	if ($current) {
		100	$main->{specific} = $current->{specific};
		101	}
		102
		103	$current = $main;
		104
		105	sub current() { $current }
		106
		107	=item $idle
		108
		109	The coroutine to switch to when no other coroutine is running. The default
		110	implementation prints "FATAL: deadlock detected" and exits.
		111
		112	=cut
		113
		114	# should be done using priorities :(
		115	$idle = new Coro sub {
		116	print STDERR "FATAL: deadlock detected\n";
		117	exit(51);
58	};	118	};
59		119
60	=item $error, $error_msg, $error_coro	120	# this coroutine is necessary because a coroutine
61		121	# cannot destroy itself.
62	This coroutine will be called on fatal errors. C<$error_msg> and	122	my @destroy;
63	C<$error_coro> return the error message and the error-causing coroutine,	123	my $manager;
64	respectively.	124	$manager = new Coro sub {
65		125	while () {
66	=cut	126	# by overwriting the state object with the manager we destroy it
67		127	# while still being able to schedule this coroutine (in case it has
68	$error_msg =	128	# been readied multiple times. this is harmless since the manager
69	$error_coro = undef;	129	# can be called as many times as neccessary and will always
70		130	# remove itself from the runqueue
71	$error = _newprocess {	131	while (@destroy) {
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	132	my $coro = pop @destroy;
73	exit 250;	133	$coro->{status} \|\|= [];
		134	$_->ready for @{delete $coro->{join} \|\| []};
		135	$coro->{_coro_state} = $manager->{_coro_state};
		136	}
		137	&schedule;
		138	}
74	};	139	};
75		140
76	=item $coro = new $coderef [, @args]	141	# static methods. not really.
77		142
78	Create a new coroutine and return it. The first C<resume> call to this	143	=back
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		144
		145	=head2 STATIC METHODS
		146
		147	Static methods are actually functions that operate on the current process only.
		148
		149	=over 4
		150
		151	=item async { ... } [@args...]
		152
		153	Create a new asynchronous process and return it's process object
		154	(usually unused). When the sub returns the new process is automatically
		155	terminated.
		156
		157	# create a new coroutine that just prints its arguments
		158	async {
		159	print "@_\n";
		160	} 1,2,3,4;
		161
83	=cut	162	=cut
		163
		164	sub async(&@) {
		165	my $pid = new Coro @_;
		166	$manager->ready; # this ensures that the stack is cloned from the manager
		167	$pid->ready;
		168	$pid;
		169	}
		170
		171	=item schedule
		172
		173	Calls the scheduler. Please note that the current process will not be put
		174	into the ready queue, so calling this function usually means you will
		175	never be called again.
		176
		177	=cut
		178
		179	=item cede
		180
		181	"Cede" to other processes. This function puts the current process into the
		182	ready queue and calls C<schedule>, which has the effect of giving up the
		183	current "timeslice" to other coroutines of the same or higher priority.
		184
		185	=cut
		186
		187	=item terminate [arg...]
		188
		189	Terminates the current process.
		190
		191	Future versions of this function will allow result arguments.
		192
		193	=cut
		194
		195	sub terminate {
		196	$current->{status} = [@_];
		197	$current->cancel;
		198	&schedule;
		199	die; # NORETURN
		200	}
		201
		202	=back
		203
		204	# dynamic methods
		205
		206	=head2 PROCESS METHODS
		207
		208	These are the methods you can call on process objects.
		209
		210	=over 4
		211
		212	=item new Coro \&sub [, @args...]
		213
		214	Create a new process and return it. When the sub returns the process
		215	automatically terminates as if C<terminate> with the returned values were
		216	called. To make the process run you must first put it into the ready queue
		217	by calling the ready method.
		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 given process into the ready queue.
102		235
103	=cut	236	=cut
104		237
105	my $prev;	238	=item $process->cancel
106		239
107	sub resume {	240	Like C<terminate>, but terminates the specified process instead.
108	$prev = $current; $current = $_[0];	241
109	_transfer($prev, $current);	242	=cut
		243
		244	sub cancel {
		245	push @destroy, $_[0];
		246	$manager->ready;
		247	&schedule if $current == $_[0];
110	}	248	}
		249
		250	=item $process->join
		251
		252	Wait until the coroutine terminates and return any values given to the
		253	C<terminate> function. C<join> can be called multiple times from multiple
		254	processes.
		255
		256	=cut
		257
		258	sub join {
		259	my $self = shift;
		260	unless ($self->{status}) {
		261	push @{$self->{join}}, $current;
		262	&schedule;
		263	}
		264	wantarray ? @{$self->{status}} : $self->{status}[0];
		265	}
		266
		267	=item $oldprio = $process->prio($newprio)
		268
		269	Sets (or gets, if the argument is missing) the priority of the
		270	process. Higher priority processes get run before lower priority
		271	processes. Priorities are small signed integers (currently -4 .. +3),
		272	that you can refer to using PRIO_xxx constants (use the import tag :prio
		273	to get then):
		274
		275	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		276	3 > 1 > 0 > -1 > -3 > -4
		277
		278	# set priority to HIGH
		279	current->prio(PRIO_HIGH);
		280
		281	The idle coroutine ($Coro::idle) always has a lower priority than any
		282	existing coroutine.
		283
		284	Changing the priority of the current process will take effect immediately,
		285	but changing the priority of processes in the ready queue (but not
		286	running) will only take effect after the next schedule (of that
		287	process). This is a bug that will be fixed in some future version.
		288
		289	=cut
		290
		291	sub prio {
		292	my $old = $_[0]{prio};
		293	$_[0]{prio} = $_[1] if @_ > 1;
		294	$old;
		295	}
		296
		297	=item $newprio = $process->nice($change)
		298
		299	Similar to C<prio>, but subtract the given value from the priority (i.e.
		300	higher values mean lower priority, just as in unix).
		301
		302	=cut
		303
		304	sub nice {
		305	$_[0]{prio} -= $_[1];
		306	}
		307
		308	=item $olddesc = $process->desc($newdesc)
		309
		310	Sets (or gets in case the argument is missing) the description for this
		311	process. This is just a free-form string you can associate with a process.
		312
		313	=cut
		314
		315	sub desc {
		316	my $old = $_[0]{desc};
		317	$_[0]{desc} = $_[1] if @_ > 1;
		318	$old;
		319	}
		320
		321	=back
		322
		323	=cut
111		324
112	1;	325	1;
113		326
114	=back	327	=head1 BUGS/LIMITATIONS
115		328
116	=head1 BUGS	329	- you must make very sure that no coro is still active on global
		330	destruction. very bad things might happen otherwise (usually segfaults).
117		331
118	This module has not yet been extensively tested.	332	- this module is not thread-safe. You should only ever use this module
		333	from the same thread (this requirement might be losened in the future
		334	to allow per-thread schedulers, but Coro::State does not yet allow
		335	this).
119		336
120	=head1 SEE ALSO	337	=head1 SEE ALSO
121		338
122	L<Coro::Process>, L<Coro::Signal>.	339	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		340	L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,
		341	L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>.
123		342
124	=head1 AUTHOR	343	=head1 AUTHOR
125		344
126	Marc Lehmann <pcg@goof.com>	345	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	346	http://www.goof.com/pcg/marc/

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing Coro/Coro.pm (file contents): Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs. Revision 1.58 by pcg, Fri Feb 13 23:17:41 2004 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.2 by root, Tue Jul 3 03:40:07 2001 UTC vs.
Revision 1.58 by pcg, Fri Feb 13 23:17:41 2004 UTC