[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 1.41 by root, Tue Nov 6 20:34:09 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	no warnings qw(uninitialized);
		38
		39	use Coro::State;
		40
		41	use base Exporter;
		42
		43	$VERSION = 0.52;
		44
		45	@EXPORT = qw(async cede schedule terminate current);
		46	%EXPORT_TAGS = (
		47	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		48	);
		49	@EXPORT_OK = @{$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	while (@destroy) {
		130	my $coro = pop @destroy;
		131	$coro->{status} \|\|= [];
		132	$_->ready for @{delete $coro->{join} \|\| []};
		133	$coro->{_coro_state} = $manager->{_coro_state};
		134	}
		135	&schedule;
		136	}
		137	};
		138
		139	# static methods. not really.
		140
		141	=head2 STATIC METHODS
		142
		143	Static methods are actually functions that operate on the current process only.
32		144
33	=over 4	145	=over 4
34		146
35	=cut	147	=item async { ... } [@args...]
36		148
37	package Coro;	149	Create a new asynchronous process and return it's process object
		150	(usually unused). When the sub returns the new process is automatically
		151	terminated.
38		152
39	BEGIN {	153	# create a new coroutine that just prints its arguments
40	$VERSION = 0.01;	154	async {
		155	print "@_\n";
		156	} 1,2,3,4;
41		157
42	require XSLoader;	158	The coderef you submit MUST NOT be a closure that refers to variables
43	XSLoader::load Coro, $VERSION;	159	in an outer scope. This does NOT work. Pass arguments into it instead.
44	}
45		160
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	161	=cut
55		162
56	$main = $current = _newprocess {	163	sub async(&@) {
57	# never being called	164	my $pid = new Coro @_;
58	};	165	$manager->ready; # this ensures that the stack is cloned from the manager
		166	$pid->ready;
		167	$pid;
		168	}
59		169
60	=item $error, $error_msg, $error_coro	170	=item schedule
61		171
62	This coroutine will be called on fatal errors. C<$error_msg> and	172	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,	173	into the ready queue, so calling this function usually means you will
64	respectively.	174	never be called again.
65		175
66	=cut	176	=cut
67		177
68	$error_msg =	178	=item cede
69	$error_coro = undef;
70		179
71	$error = _newprocess {	180	"Cede" to other processes. This function puts the current process into the
72	print STDERR "FATAL: $error_msg\nprogram aborted\n";	181	ready queue and calls C<schedule>, which has the effect of giving up the
73	exit 250;	182	current "timeslice" to other coroutines of the same or higher priority.
74	};
75		183
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	184	=cut
		185
		186	=item terminate [arg...]
		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->{status} = [@_];
		196	$current->cancel;
		197	&schedule;
		198	die; # NORETURN
		199	}
		200
		201	=back
		202
		203	# dynamic methods
		204
		205	=head2 PROCESS METHODS
		206
		207	These are the methods you can call on process objects.
		208
		209	=over 4
		210
		211	=item new Coro \&sub [, @args...]
		212
		213	Create a new process and return it. When the sub returns the process
		214	automatically terminates as if C<terminate> with the returned values were
		215	called. To make the process run you must first put it into the ready queue
		216	by calling the ready method.
		217
		218	=cut
		219
		220	sub _newcoro {
		221	terminate &{+shift};
		222	}
84		223
85	sub new {	224	sub new {
86	my $class = $_[0];	225	my $class = shift;
87	my $proc = $_[1];	226	bless {
88	bless _newprocess {	227	_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;	228	}, $class;
97	}	229	}
98		230
99	=item $coro->resume	231	=item $process->ready
100		232
101	Resume execution at the given coroutine.	233	Put the given process into the ready queue.
102		234
103	=cut	235	=cut
104		236
105	my $prev;	237	=item $process->cancel
106		238
107	sub resume {	239	Like C<terminate>, but terminates the specified process instead.
108	$prev = $current; $current = $_[0];	240
109	_transfer($prev, $current);	241	=cut
		242
		243	sub cancel {
		244	push @destroy, $_[0];
		245	$manager->ready;
		246	&schedule if $current == $_[0];
110	}	247	}
		248
		249	=item $process->join
		250
		251	Wait until the coroutine terminates and return any values given to the
		252	C<terminate> function. C<join> can be called multiple times from multiple
		253	processes.
		254
		255	=cut
		256
		257	sub join {
		258	my $self = shift;
		259	unless ($self->{status}) {
		260	push @{$self->{join}}, $current;
		261	&schedule;
		262	}
		263	wantarray ? @{$self->{status}} : $self->{status}[0];
		264	}
		265
		266	=item $oldprio = $process->prio($newprio)
		267
		268	Sets (or gets, if the argument is missing) the priority of the
		269	process. Higher priority processes get run before lower priority
		270	processes. Priorities are smalled signed integer (currently -4 .. +3),
		271	that you can refer to using PRIO_xxx constants (use the import tag :prio
		272	to get then):
		273
		274	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		275	3 > 1 > 0 > -1 > -3 > -4
		276
		277	# set priority to HIGH
		278	current->prio(PRIO_HIGH);
		279
		280	The idle coroutine ($Coro::idle) always has a lower priority than any
		281	existing coroutine.
		282
		283	Changing the priority of the current process will take effect immediately,
		284	but changing the priority of processes in the ready queue (but not
		285	running) will only take effect after the next schedule (of that
		286	process). This is a bug that will be fixed in some future version.
		287
		288	=cut
		289
		290	sub prio {
		291	my $old = $_[0]{prio};
		292	$_[0]{prio} = $_[1] if @_ > 1;
		293	$old;
		294	}
		295
		296	=item $newprio = $process->nice($change)
		297
		298	Similar to C<prio>, but subtract the given value from the priority (i.e.
		299	higher values mean lower priority, just as in unix).
		300
		301	=cut
		302
		303	sub nice {
		304	$_[0]{prio} -= $_[1];
		305	}
		306
		307	=item $olddesc = $process->desc($newdesc)
		308
		309	Sets (or gets in case the argument is missing) the description for this
		310	process. This is just a free-form string you can associate with a process.
		311
		312	=cut
		313
		314	sub desc {
		315	my $old = $_[0]{desc};
		316	$_[0]{desc} = $_[1] if @_ > 1;
		317	$old;
		318	}
		319
		320	=back
		321
		322	=cut
111		323
112	1;	324	1;
113		325
114	=back	326	=head1 BUGS/LIMITATIONS
115		327
116	=head1 BUGS	328	- you must make very sure that no coro is still active on global destruction.
117		329	very bad things might happen otherwise (usually segfaults).
118	This module has not yet been extensively tested.	330	- this module is not thread-safe. You must only ever use this module from
		331	the same thread (this requirement might be loosened in the future to
		332	allow per-thread schedulers, but Coro::State does not yet allow this).
119		333
120	=head1 SEE ALSO	334	=head1 SEE ALSO
121		335
122	L<Coro::Process>, L<Coro::Signal>.	336	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		337	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		338	L<Coro::Handle>, L<Coro::Socket>.
123		339
124	=head1 AUTHOR	340	=head1 AUTHOR
125		341
126	Marc Lehmann <pcg@goof.com>	342	Marc Lehmann <pcg@goof.com>
127	http://www.goof.com/pcg/marc/	343	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 1.41 by root, Tue Nov 6 20:34:09 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 1.41 by root, Tue Nov 6 20:34:09 2001 UTC