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

Comparing Coro/Coro.pm (file contents):
Revision 1.22 by root, Mon Jul 23 02:14:19 2001 UTC vs.
Revision 1.85 by root, Sat Nov 25 00:56:35 2006 UTC

…		…
19	cede;	19	cede;
20		20
21	=head1 DESCRIPTION	21	=head1 DESCRIPTION
22		22
23	This module collection manages coroutines. Coroutines are similar to	23	This module collection manages coroutines. Coroutines are similar to
24	Threads but don't run in parallel.	24	threads but don't run in parallel.
25
26	This module is still experimental, see the BUGS section below.
27		25
28	In this module, coroutines are defined as "callchain + lexical variables	26	In this module, coroutines are defined as "callchain + lexical variables
29	+ @_ + $_ + $@ + $^W), that is, a coroutine has it's own callchain, it's	27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30	own set of lexicals and it's own set of perl's most important global	28	callchain, it's own set of lexicals and it's own set of perl's most
31	variables.	29	important global variables.
32
33	WARNING: When using this module, make sure that, at program end, no
34	coroutines are still running OR just call exit before falling off the
35	end. The reason for this is that some coroutine of yours might have called
36	into a C function, and falling off the end of main:: results in returning
37	to that C function instead if to the main C interpreter.
38
39	WARNING: Unless you really know what you are doing, do NOT do context
40	switches inside callbacks from the XS level. The reason for this is
41	similar to the reason above: A callback calls a perl function, this
42	perl function does a context switch, some other callback is called, the
43	original function returns from it - to what? To the wrong XS function,
44	with totally different return values. Unfortunately, this includes
45	callbacks done by perl itself (tie'd variables!).
46
47	The only workaround for this is to do coroutines on C level.
48		30
49	=cut	31	=cut
50		32
51	package Coro;	33	package Coro;
52		34
		35	use strict;
		36	no warnings "uninitialized";
		37
53	use Coro::State;	38	use Coro::State;
54		39
55	use base Exporter;	40	use base qw(Coro::State Exporter);
56		41
57	$VERSION = 0.10;	42	our $idle; # idle handler
		43	our $main; # main coroutine
		44	our $current; # current coroutine
58		45
		46	our $VERSION = '2.5';
		47
59	@EXPORT = qw(async cede schedule terminate current);	48	our @EXPORT = qw(async cede schedule terminate current);
60	@EXPORT_OK = qw($current);	49	our %EXPORT_TAGS = (
		50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
		51	);
		52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
61		53
62	{	54	{
63	my @async;	55	my @async;
		56	my $init;
64		57
65	# this way of handling attributes simply is NOT scalable ;()	58	# this way of handling attributes simply is NOT scalable ;()
66	sub import {	59	sub import {
		60	no strict 'refs';
		61
67	Coro->export_to_level(1, @_);	62	Coro->export_to_level(1, @_);
		63
68	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
69	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
70	my ($package, $ref) = (shift, shift);	66	my ($package, $ref) = (shift, shift);
71	my @attrs;	67	my @attrs;
72	for (@_) {	68	for (@_) {
73	if ($_ eq "Coro") {	69	if ($_ eq "Coro") {
74	push @async, $ref;	70	push @async, $ref;
		71	unless ($init++) {
		72	eval q{
		73	sub INIT {
		74	&async(pop @async) while @async;
		75	}
		76	};
		77	}
75	} else {	78	} else {
76	push @attrs, $_;	79	push @attrs, $_;
77	}	80	}
78	}	81	}
79	return $old ? $old->($package, $ref, @attrs) : @attrs;	82	return $old ? $old->($package, $ref, @attrs) : @attrs;
80	};	83	};
81	}	84	}
82		85
83	sub INIT {
84	&async(pop @async) while @async;
85	}
86	}	86	}
		87
		88	=over 4
87		89
88	=item $main	90	=item $main
89		91
90	This coroutine represents the main program.	92	This coroutine represents the main program.
91		93
92	=cut	94	=cut
93		95
94	our $main = new Coro;	96	$main = new Coro;
95		97
96	=item $current (or as function: current)	98	=item $current (or as function: current)
97		99
98	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	100	The current coroutine (the last coroutine switched to). The initial value
		101	is C<$main> (of course).
		102
		103	This variable is B<strictly> I<read-only>. It is provided for performance
		104	reasons. If performance is not essentiel you are encouraged to use the
		105	C<Coro::current> function instead.
99		106
100	=cut	107	=cut
101		108
102	# maybe some other module used Coro::Specific before...	109	# maybe some other module used Coro::Specific before...
103	if ($current) {	110	if ($current) {
104	$main->{specific} = $current->{specific};	111	$main->{specific} = $current->{specific};
105	}	112	}
106		113
107	our $current = $main;	114	$current = $main;
108		115
109	sub current() { $current }	116	sub current() { $current }
110		117
111	=item $idle	118	=item $idle
112		119
113	The coroutine to switch to when no other coroutine is running. The default	120	A callback that is called whenever the scheduler finds no ready coroutines
114	implementation prints "FATAL: deadlock detected" and exits.	121	to run. The default implementation prints "FATAL: deadlock detected" and
		122	exits.
115		123
116	=cut	124	This hook is overwritten by modules such as C<Coro::Timer> and
		125	C<Coro::Event> to wait on an external event that hopefully wakes up some
		126	coroutine.
117		127
118	# should be done using priorities :(	128	=cut
119	our $idle = new Coro sub {	129
		130	$idle = sub {
120	print STDERR "FATAL: deadlock detected\n";	131	print STDERR "FATAL: deadlock detected\n";
121	exit(51);	132	exit (51);
122	};	133	};
123		134
124	# we really need priorities...	135	# this coroutine is necessary because a coroutine
125	my @ready; # the ready queue. hehe, rather broken ;)	136	# cannot destroy itself.
		137	my @destroy;
		138	my $manager;
		139	$manager = new Coro sub {
		140	while () {
		141	# by overwriting the state object with the manager we destroy it
		142	# while still being able to schedule this coroutine (in case it has
		143	# been readied multiple times. this is harmless since the manager
		144	# can be called as many times as neccessary and will always
		145	# remove itself from the runqueue
		146	while (@destroy) {
		147	my $coro = pop @destroy;
		148	$coro->{status} \|\|= [];
		149	$_->ready for @{delete $coro->{join} \|\| []};
		150
		151	# the next line destroys the coro state, but keeps the
		152	# process itself intact (we basically make it a zombie
		153	# process that always runs the manager thread, so it's possible
		154	# to transfer() to this process).
		155	$coro->_clone_state_from ($manager);
		156	}
		157	&schedule;
		158	}
		159	};
126		160
127	# static methods. not really.	161	# static methods. not really.
		162
		163	=back
128		164
129	=head2 STATIC METHODS	165	=head2 STATIC METHODS
130		166
131	Static methods are actually functions that operate on the current process only.	167	Static methods are actually functions that operate on the current process only.
132		168
…		…
135	=item async { ... } [@args...]	171	=item async { ... } [@args...]
136		172
137	Create a new asynchronous process and return it's process object	173	Create a new asynchronous process and return it's process object
138	(usually unused). When the sub returns the new process is automatically	174	(usually unused). When the sub returns the new process is automatically
139	terminated.	175	terminated.
		176
		177	When the coroutine dies, the program will exit, just as in the main
		178	program.
140		179
141	# create a new coroutine that just prints its arguments	180	# create a new coroutine that just prints its arguments
142	async {	181	async {
143	print "@_\n";	182	print "@_\n";
144	} 1,2,3,4;	183	} 1,2,3,4;
145		184
146	The coderef you submit MUST NOT be a closure that refers to variables
147	in an outer scope. This does NOT work. Pass arguments into it instead.
148
149	=cut	185	=cut
150		186
151	sub async(&@) {	187	sub async(&@) {
152	my $pid = new Coro @_;	188	my $pid = new Coro @_;
153	$pid->ready;	189	$pid->ready;
154	$pid;	190	$pid
155	}	191	}
156		192
157	=item schedule	193	=item schedule
158		194
159	Calls the scheduler. Please note that the current process will not be put	195	Calls the scheduler. Please note that the current process will not be put
160	into the ready queue, so calling this function usually means you will	196	into the ready queue, so calling this function usually means you will
161	never be called again.	197	never be called again.
162		198
163	=cut	199	=cut
164		200
165	my $prev;
166
167	sub schedule {
168	# should be done using priorities :(
169	($prev, $current) = ($current, shift @ready \|\| $idle);
170	Coro::State::transfer($prev, $current);
171	}
172
173	=item cede	201	=item cede
174		202
175	"Cede" to other processes. This function puts the current process into the	203	"Cede" to other processes. This function puts the current process into the
176	ready queue and calls C<schedule>, which has the effect of giving up the	204	ready queue and calls C<schedule>, which has the effect of giving up the
177	current "timeslice" to other coroutines of the same or higher priority.	205	current "timeslice" to other coroutines of the same or higher priority.
178		206
179	=cut	207	=cut
180		208
181	sub cede {
182	$current->ready;
183	&schedule;
184	}
185
186	=item terminate	209	=item terminate [arg...]
187		210
188	Terminates the current process.	211	Terminates the current process with the given status values (see L<cancel>).
189
190	Future versions of this function will allow result arguments.
191		212
192	=cut	213	=cut
193		214
194	sub terminate {	215	sub terminate {
195	my $self = $current;	216	$current->cancel (@_);
196	$self->{_results} = [@_];
197	$current = shift @ready \|\| $idle;
198	Coro::State::transfer(delete $self->{_coro_state}, $current);
199	# cannot return
200	die;
201	}	217	}
202		218
203	=back	219	=back
204		220
205	# dynamic methods	221	# dynamic methods
…		…
211	=over 4	227	=over 4
212		228
213	=item new Coro \&sub [, @args...]	229	=item new Coro \&sub [, @args...]
214		230
215	Create a new process and return it. When the sub returns the process	231	Create a new process and return it. When the sub returns the process
216	automatically terminates. To start the process you must first put it into	232	automatically terminates as if C<terminate> with the returned values were
		233	called. To make the process run you must first put it into the ready queue
217	the ready queue by calling the ready method.	234	by calling the ready method.
218		235
219	The coderef you submit MUST NOT be a closure that refers to variables
220	in an outer scope. This does NOT work. Pass arguments into it instead.
221
222	=cut	236	=cut
223		237
224	sub _newcoro {	238	sub _new_coro {
		239	$current->_clear_idle_sp; # set the idle sp on the following cede
		240	_set_cede_self; # ensures that cede cede's us first
		241	cede;
225	terminate &{+shift};	242	terminate &{+shift};
226	}	243	}
227		244
228	sub new {	245	sub new {
229	my $class = shift;	246	my $class = shift;
230	bless {	247
231	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),	248	$class->SUPER::new (\&_new_coro, @_)
232	}, $class;
233	}	249	}
234		250
235	=item $process->ready	251	=item $process->ready
236		252
237	Put the current process into the ready queue.	253	Put the given process into the ready queue.
238		254
239	=cut	255	=cut
240		256
241	sub ready {	257	=item $process->cancel (arg...)
242	push @ready, $_[0];	258
		259	Terminates the given process and makes it return the given arguments as
		260	status (default: the empty list).
		261
		262	=cut
		263
		264	sub cancel {
		265	my $self = shift;
		266	$self->{status} = [@_];
		267	push @destroy, $self;
		268	$manager->ready;
		269	&schedule if $current == $self;
		270	}
		271
		272	=item $process->join
		273
		274	Wait until the coroutine terminates and return any values given to the
		275	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		276	from multiple processes.
		277
		278	=cut
		279
		280	sub join {
		281	my $self = shift;
		282	unless ($self->{status}) {
		283	push @{$self->{join}}, $current;
		284	&schedule;
		285	}
		286	wantarray ? @{$self->{status}} : $self->{status}[0];
		287	}
		288
		289	=item $oldprio = $process->prio ($newprio)
		290
		291	Sets (or gets, if the argument is missing) the priority of the
		292	process. Higher priority processes get run before lower priority
		293	processes. Priorities are small signed integers (currently -4 .. +3),
		294	that you can refer to using PRIO_xxx constants (use the import tag :prio
		295	to get then):
		296
		297	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		298	3 > 1 > 0 > -1 > -3 > -4
		299
		300	# set priority to HIGH
		301	current->prio(PRIO_HIGH);
		302
		303	The idle coroutine ($Coro::idle) always has a lower priority than any
		304	existing coroutine.
		305
		306	Changing the priority of the current process will take effect immediately,
		307	but changing the priority of processes in the ready queue (but not
		308	running) will only take effect after the next schedule (of that
		309	process). This is a bug that will be fixed in some future version.
		310
		311	=item $newprio = $process->nice ($change)
		312
		313	Similar to C<prio>, but subtract the given value from the priority (i.e.
		314	higher values mean lower priority, just as in unix).
		315
		316	=item $olddesc = $process->desc ($newdesc)
		317
		318	Sets (or gets in case the argument is missing) the description for this
		319	process. This is just a free-form string you can associate with a process.
		320
		321	=cut
		322
		323	sub desc {
		324	my $old = $_[0]{desc};
		325	$_[0]{desc} = $_[1] if @_ > 1;
		326	$old;
243	}	327	}
244		328
245	=back	329	=back
246		330
247	=cut	331	=cut
248		332
249	1;	333	1;
250		334
251	=head1 BUGS/LIMITATIONS	335	=head1 BUGS/LIMITATIONS
252		336
253	- could be faster, especially when the core would introduce special	337	- you must make very sure that no coro is still active on global
254	support for coroutines (like it does for threads).	338	destruction. very bad things might happen otherwise (usually segfaults).
255	- there is still a memleak on coroutine termination that I could not	339
256	identify. Could be as small as a single SV.
257	- this module is not well-tested.
258	- if variables or arguments "disappear" (become undef) or become
259	corrupted please contact the author so he cen iron out the
260	remaining bugs.
261	- this module is not thread-safe. You must only ever use this module from	340	- this module is not thread-safe. You should only ever use this module
262	the same thread (this requirement might be loosened in the future to	341	from the same thread (this requirement might be losened in the future
263	allow per-thread schedulers, but Coro::State does not yet allow this).	342	to allow per-thread schedulers, but Coro::State does not yet allow
		343	this).
264		344
265	=head1 SEE ALSO	345	=head1 SEE ALSO
266		346
267	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	347	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
268	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.	348
		349	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		350
		351	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		352
		353	Embedding: L<Coro:MakeMaker>
269		354
270	=head1 AUTHOR	355	=head1 AUTHOR
271		356
272	Marc Lehmann <pcg@goof.com>	357	Marc Lehmann <schmorp@schmorp.de>
273	http://www.goof.com/pcg/marc/	358	http://home.schmorp.de/
274		359
275	=cut	360	=cut
276		361

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Comparing Coro/Coro.pm (file contents): Revision 1.22 by root, Mon Jul 23 02:14:19 2001 UTC vs. Revision 1.85 by root, Sat Nov 25 00:56:35 2006 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.22 by root, Mon Jul 23 02:14:19 2001 UTC vs.
Revision 1.85 by root, Sat Nov 25 00:56:35 2006 UTC