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

Comparing Coro/Coro.pm (file contents):
Revision 1.5 by root, Tue Jul 10 01:43:21 2001 UTC vs.
Revision 1.40 by root, Sun Oct 28 17:00:05 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	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 = 0.03;	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 start the process you must first put it into the ready queue by
		216	calling the ready method.
		217
		218	The coderef you submit MUST NOT be a closure that refers to variables
		219	in an outer scope. This does NOT work. Pass arguments into it instead.
		220
		221	=cut
		222
		223	sub _newcoro {
		224	terminate &{+shift};
		225	}
84		226
85	sub new {	227	sub new {
86	my $class = $_[0];	228	my $class = shift;
87	my $proc = $_[1];	229	bless {
88	bless _newprocess {	230	_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;	231	}, $class;
97	}	232	}
98		233
99	=item $coro->resume	234	=item $process->ready
100		235
101	Resume execution at the given coroutine.	236	Put the given process into the ready queue.
102		237
103	=cut	238	=cut
104		239
105	my $prev;	240	=item $process->cancel
106		241
107	# I call the _transfer function from a pelr function	242	Like C<terminate>, but terminates the specified process instead.
108	# because that way perl saves all important things on	243
109	# the stack.	244	=cut
110	sub resume {	245
111	$prev = $current; $current = $_[0];	246	sub cancel {
112	_transfer($prev, $current);	247	push @destroy, $_[0];
		248	$manager->ready;
		249	&schedule if $current == $_[0];
113	}	250	}
		251
		252	=item $process->join
		253
		254	Wait until the coroutine terminates and return any values given to the
		255	C<terminate> function. C<join> can be called multiple times from multiple
		256	processes.
		257
		258	=cut
		259
		260	sub join {
		261	my $self = shift;
		262	unless ($self->{status}) {
		263	push @{$self->{join}}, $current;
		264	&schedule;
		265	}
		266	wantarray ? @{$self->{status}} : $self->{status}[0];
		267	}
		268
		269	=item $oldprio = $process->prio($newprio)
		270
		271	Sets the priority of the process. Higher priority processes get run before
		272	lower priority processes. Priorities are smalled signed integer (currently
		273	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import
		274	tag :prio to get then):
		275
		276	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		277	3 > 1 > 0 > -1 > -3 > -4
		278
		279	# set priority to HIGH
		280	current->prio(PRIO_HIGH);
		281
		282	The idle coroutine ($Coro::idle) always has a lower priority than any
		283	existing coroutine.
		284
		285	Changing the priority of the current process will take effect immediately,
		286	but changing the priority of processes in the ready queue (but not
		287	running) will only take effect after the next schedule (of that
		288	process). This is a bug that will be fixed in some future version.
		289
		290	=cut
		291
		292	sub prio {
		293	my $old = $_[0]{prio};
		294	$_[0]{prio} = $_[1] if @_ > 1;
		295	$old;
		296	}
		297
		298	=item $newprio = $process->nice($change)
		299
		300	Similar to C<prio>, but subtract the given value from the priority (i.e.
		301	higher values mean lower priority, just as in unix).
		302
		303	=cut
		304
		305	sub nice {
		306	$_[0]{prio} -= $_[1];
		307	}
		308
		309	=back
		310
		311	=cut
114		312
115	1;	313	1;
116		314
117	=back	315	=head1 BUGS/LIMITATIONS
118		316
119	=head1 BUGS	317	- you must make very sure that no coro is still active on global destruction.
120		318	very bad things might happen otherwise (usually segfaults).
121	This module has not yet been extensively tested.	319	- this module is not thread-safe. You must only ever use this module from
		320	the same thread (this requirement might be loosened in the future to
		321	allow per-thread schedulers, but Coro::State does not yet allow this).
122		322
123	=head1 SEE ALSO	323	=head1 SEE ALSO
124		324
125	L<Coro::Process>, L<Coro::Signal>.	325	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
		326	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
		327	L<Coro::Handle>, L<Coro::Socket>.
126		328
127	=head1 AUTHOR	329	=head1 AUTHOR
128		330
129	Marc Lehmann <pcg@goof.com>	331	Marc Lehmann <pcg@goof.com>
130	http://www.goof.com/pcg/marc/	332	http://www.goof.com/pcg/marc/

Diff Legend

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

Comparing Coro/Coro.pm (file contents): Revision 1.5 by root, Tue Jul 10 01:43:21 2001 UTC vs. Revision 1.40 by root, Sun Oct 28 17:00:05 2001 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.5 by root, Tue Jul 10 01:43:21 2001 UTC vs.
Revision 1.40 by root, Sun Oct 28 17:00:05 2001 UTC