[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 1.31 by root, Sat Aug 11 23:10:56 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	use Coro::State;
		38
		39	use base Exporter;
		40
		41	$VERSION = 0.45;
		42
		43	@EXPORT = qw(async cede schedule terminate current);
		44	%EXPORT_TAGS = (
		45	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		46	);
		47	@EXPORT_OK = @{$EXPORT_TAGS{prio}};
		48
		49	{
		50	my @async;
		51	my $init;
		52
		53	# this way of handling attributes simply is NOT scalable ;()
		54	sub import {
		55	Coro->export_to_level(1, @_);
		56	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
		57	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
		58	my ($package, $ref) = (shift, shift);
		59	my @attrs;
		60	for (@_) {
		61	if ($_ eq "Coro") {
		62	push @async, $ref;
		63	unless ($init++) {
		64	eval q{
		65	sub INIT {
		66	&async(pop @async) while @async;
		67	}
		68	};
		69	}
		70	} else {
		71	push @attrs, $_;
		72	}
		73	}
		74	return $old ? $old->($package, $ref, @attrs) : @attrs;
		75	};
		76	}
		77
		78	}
		79
		80	=item $main
		81
		82	This coroutine represents the main program.
		83
		84	=cut
		85
		86	our $main = new Coro;
		87
		88	=item $current (or as function: current)
		89
		90	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
		91
		92	=cut
		93
		94	# maybe some other module used Coro::Specific before...
		95	if ($current) {
		96	$main->{specific} = $current->{specific};
		97	}
		98
		99	our $current = $main;
		100
		101	sub current() { $current }
		102
		103	=item $idle
		104
		105	The coroutine to switch to when no other coroutine is running. The default
		106	implementation prints "FATAL: deadlock detected" and exits.
		107
		108	=cut
		109
		110	# should be done using priorities :(
		111	our $idle = new Coro sub {
		112	print STDERR "FATAL: deadlock detected\n";
		113	exit(51);
		114	};
		115
		116	# this coroutine is necessary because a coroutine
		117	# cannot destroy itself.
		118	my @destroy;
		119	my $manager = new Coro sub {
		120	while() {
		121	delete ((pop @destroy)->{_coro_state}) while @destroy;
		122	&schedule;
		123	}
		124	};
		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	=item cede
69	$error_coro = undef;
70		166
71	$error = _newprocess {	167	"Cede" to other processes. This function puts the current process into the
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	168	ready queue and calls C<schedule>, which has the effect of giving up the
73	exit 250;	169	current "timeslice" to other coroutines of the same or higher priority.
74	};
75		170
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	171	=cut
		172
		173	=item terminate
		174
		175	Terminates the current process.
		176
		177	Future versions of this function will allow result arguments.
		178
		179	=cut
		180
		181	sub terminate {
		182	$current->cancel;
		183	&schedule;
		184	die; # NORETURN
		185	}
		186
		187	=back
		188
		189	# dynamic methods
		190
		191	=head2 PROCESS METHODS
		192
		193	These are the methods you can call on process objects.
		194
		195	=over 4
		196
		197	=item new Coro \&sub [, @args...]
		198
		199	Create a new process and return it. When the sub returns the process
		200	automatically terminates. To start the process you must first put it into
		201	the ready queue by calling the ready method.
		202
		203	The coderef you submit MUST NOT be a closure that refers to variables
		204	in an outer scope. This does NOT work. Pass arguments into it instead.
		205
		206	=cut
		207
		208	sub _newcoro {
		209	terminate &{+shift};
		210	}
84		211
85	sub new {	212	sub new {
86	my $class = $_[0];	213	my $class = shift;
87	my $proc = $_[1];	214	bless {
88	bless _newprocess {	215	_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;	216	}, $class;
97	}	217	}
98		218
99	=item $coro->resume	219	=item $process->ready
100		220
101	Resume execution at the given coroutine.	221	Put the current process into the ready queue.
102		222
103	=cut	223	=cut
104		224
105	my $prev;	225	=item $process->cancel
106		226
107	sub resume {	227	Like C<terminate>, but terminates the specified process instead.
108	$prev = $current; $current = $_[0];	228
109	_transfer($prev, $current);	229	=cut
		230
		231	sub cancel {
		232	push @destroy, $_[0];
		233	$manager->ready;
110	}	234	}
		235
		236	=item $oldprio = $process->prio($newprio)
		237
		238	Sets the priority of the process. Higher priority processes get run before
		239	lower priority processes. Priorities are smalled signed integer (currently
		240	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import
		241	tag :prio to get then):
		242
		243	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		244	3 > 1 > 0 > -1 > -3 > -4
		245
		246	# set priority to HIGH
		247	current->prio(PRIO_HIGH);
		248
		249	The idle coroutine ($Coro::idle) always has a lower priority than any
		250	existing coroutine.
		251
		252	Changing the priority of the current process will take effect immediately,
		253	but changing the priority of processes in the ready queue (but not
		254	running) will only take effect after the next schedule (of that
		255	process). This is a bug that will be fixed in some future version.
		256
		257	=cut
		258
		259	sub prio {
		260	my $old = $_[0]{prio};
		261	$_[0]{prio} = $_[1] if @_ > 1;
		262	$old;
		263	}
		264
		265	=item $newprio = $process->nice($change)
		266
		267	Similar to C<prio>, but subtract the given value from the priority (i.e.
		268	higher values mean lower priority, just as in unix).
		269
		270	=cut
		271
		272	sub nice {
		273	$_[0]{prio} -= $_[1];
		274	}
		275
		276	=back
		277
		278	=cut
111		279
112	1;	280	1;
113		281
114	=back	282	=head1 BUGS/LIMITATIONS
115		283
116	=head1 BUGS	284	- could be faster, especially when the core would introduce special
117		285	support for coroutines (like it does for threads).
118	This module has not yet been extensively tested.	286	- there is still a memleak on coroutine termination that I could not
		287	identify. Could be as small as a single SV.
		288	- this module is not well-tested.
		289	- if variables or arguments "disappear" (become undef) or become
		290	corrupted please contact the author so he cen iron out the
		291	remaining bugs.
		292	- this module is not thread-safe. You must only ever use this module from
		293	the same thread (this requirement might be loosened in the future to
		294	allow per-thread schedulers, but Coro::State does not yet allow this).
119		295
120	=head1 SEE ALSO	296	=head1 SEE ALSO
121		297
122	L<Coro::Process>, L<Coro::Signal>.	298	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		299	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		300	L<Coro::Handle>, L<Coro::Socket>.
123		301
124	=head1 AUTHOR	302	=head1 AUTHOR
125		303
126	Marc Lehmann <pcg@goof.com>	304	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	305	http://www.goof.com/pcg/marc/

Diff Legend

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

Comparing Coro/Coro.pm (file contents): Revision 1.4 by root, Tue Jul 3 05:05:45 2001 UTC vs. Revision 1.31 by root, Sat Aug 11 23:10:56 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 1.31 by root, Sat Aug 11 23:10:56 2001 UTC