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

Comparing Coro/Coro.pm (file contents):
Revision 1.35 by root, Mon Sep 24 00:16:30 2001 UTC vs.
Revision 1.100 by root, Tue Dec 12 13:56:45 2006 UTC

…		…
8		8
9	async {	9	async {
10	# some asynchronous thread of execution	10	# some asynchronous thread of execution
11	};	11	};
12		12
13	# alternatively create an async process like this:	13	# alternatively create an async coroutine like this:
14		14
15	sub some_func : Coro {	15	sub some_func : Coro {
16	# some more async code	16	# some more async code
17	}	17	}
18		18
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
24	Threads but don't run in parallel.	24	to threads but don't run in parallel at the same time even on SMP
		25	machines. The specific flavor of coroutine use din this module also
		26	guarentees you that it will not switch between coroutines unless
		27	necessary, at easily-identified points in your program, so locking and
		28	parallel access are rarely an issue, making coroutine programming much
		29	safer than threads programming.
25		30
26	This module is still experimental, see the BUGS section below.	31	(Perl, however, does not natively support real threads but instead does a
		32	very slow and memory-intensive emulation of processes using threads. This
		33	is a performance win on Windows machines, and a loss everywhere else).
27		34
28	In this module, coroutines are defined as "callchain + lexical variables	35	In this module, coroutines are defined as "callchain + lexical variables +
29	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own	36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
30	callchain, it's own set of lexicals and it's own set of perl's most	37	its own set of lexicals and its own set of perls most important global
31	important global variables.	38	variables.
32		39
33	=cut	40	=cut
34		41
35	package Coro;	42	package Coro;
36		43
		44	use strict;
		45	no warnings "uninitialized";
		46
37	use Coro::State;	47	use Coro::State;
38		48
39	use base Exporter;	49	use base qw(Coro::State Exporter);
40		50
41	$VERSION = 0.5;	51	our $idle; # idle handler
		52	our $main; # main coroutine
		53	our $current; # current coroutine
42		54
		55	our $VERSION = '3.2';
		56
43	@EXPORT = qw(async cede schedule terminate current);	57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
44	%EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
45	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
46	);	60	);
47	@EXPORT_OK = @{$EXPORT_TAGS{prio}};	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
48		62
49	{	63	{
50	my @async;	64	my @async;
51	my $init;	65	my $init;
52		66
53	# this way of handling attributes simply is NOT scalable ;()	67	# this way of handling attributes simply is NOT scalable ;()
54	sub import {	68	sub import {
		69	no strict 'refs';
		70
55	Coro->export_to_level(1, @_);	71	Coro->export_to_level (1, @_);
		72
56	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
57	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
58	my ($package, $ref) = (shift, shift);	75	my ($package, $ref) = (shift, shift);
59	my @attrs;	76	my @attrs;
60	for (@_) {	77	for (@_) {
…		…
75	};	92	};
76	}	93	}
77		94
78	}	95	}
79		96
		97	=over 4
		98
80	=item $main	99	=item $main
81		100
82	This coroutine represents the main program.	101	This coroutine represents the main program.
83		102
84	=cut	103	=cut
85		104
86	our $main = new Coro;	105	$main = new Coro;
87		106
88	=item $current (or as function: current)	107	=item $current (or as function: current)
89		108
90	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	109	The current coroutine (the last coroutine switched to). The initial value
		110	is C<$main> (of course).
		111
		112	This variable is B<strictly> I<read-only>. It is provided for performance
		113	reasons. If performance is not essentiel you are encouraged to use the
		114	C<Coro::current> function instead.
91		115
92	=cut	116	=cut
93		117
94	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
95	if ($current) {
96	$main->{specific} = $current->{specific};	119	$main->{specific} = $current->{specific}
97	}	120	if $current;
98		121
99	our $current = $main;	122	_set_current $main;
100		123
101	sub current() { $current }	124	sub current() { $current }
102		125
103	=item $idle	126	=item $idle
104		127
105	The coroutine to switch to when no other coroutine is running. The default	128	A callback that is called whenever the scheduler finds no ready coroutines
106	implementation prints "FATAL: deadlock detected" and exits.	129	to run. The default implementation prints "FATAL: deadlock detected" and
		130	exits, because the program has no other way to continue.
107		131
108	=cut	132	This hook is overwritten by modules such as C<Coro::Timer> and
		133	C<Coro::Event> to wait on an external event that hopefully wake up a
		134	coroutine so the scheduler can run it.
109		135
110	# should be done using priorities :(	136	Please note that if your callback recursively invokes perl (e.g. for event
111	our $idle = new Coro sub {	137	handlers), then it must be prepared to be called recursively.
112	print STDERR "FATAL: deadlock detected\n";	138
113	exit(51);	139	=cut
		140
		141	$idle = sub {
		142	require Carp;
		143	Carp::croak ("FATAL: deadlock detected");
114	};	144	};
115		145
116	# this coroutine is necessary because a coroutine	146	# this coroutine is necessary because a coroutine
117	# cannot destroy itself.	147	# cannot destroy itself.
118	my @destroy;	148	my @destroy;
119	my $manager = new Coro sub {	149	my $manager; $manager = new Coro sub {
120	while() {	150	while () {
121	delete ((pop @destroy)->{_coro_state}) while @destroy;	151	# by overwriting the state object with the manager we destroy it
		152	# while still being able to schedule this coroutine (in case it has
		153	# been readied multiple times. this is harmless since the manager
		154	# can be called as many times as neccessary and will always
		155	# remove itself from the runqueue
		156	while (@destroy) {
		157	my $coro = pop @destroy;
		158	$coro->{status} \|\|= [];
		159	$_->ready for @{delete $coro->{join} \|\| []};
		160
		161	# the next line destroys the coro state, but keeps the
		162	# coroutine itself intact (we basically make it a zombie
		163	# coroutine that always runs the manager thread, so it's possible
		164	# to transfer() to this coroutine).
		165	$coro->_clone_state_from ($manager);
		166	}
122	&schedule;	167	&schedule;
123	}	168	}
124	};	169	};
125		170
126	# static methods. not really.	171	# static methods. not really.
127		172
		173	=back
		174
128	=head2 STATIC METHODS	175	=head2 STATIC METHODS
129		176
130	Static methods are actually functions that operate on the current process only.	177	Static methods are actually functions that operate on the current coroutine only.
131		178
132	=over 4	179	=over 4
133		180
134	=item async { ... } [@args...]	181	=item async { ... } [@args...]
135		182
136	Create a new asynchronous process and return it's process object	183	Create a new asynchronous coroutine and return it's coroutine object
137	(usually unused). When the sub returns the new process is automatically	184	(usually unused). When the sub returns the new coroutine is automatically
138	terminated.	185	terminated.
		186
		187	Calling C<exit> in a coroutine will not work correctly, so do not do that.
		188
		189	When the coroutine dies, the program will exit, just as in the main
		190	program.
139		191
140	# create a new coroutine that just prints its arguments	192	# create a new coroutine that just prints its arguments
141	async {	193	async {
142	print "@_\n";	194	print "@_\n";
143	} 1,2,3,4;	195	} 1,2,3,4;
144		196
145	The coderef you submit MUST NOT be a closure that refers to variables
146	in an outer scope. This does NOT work. Pass arguments into it instead.
147
148	=cut	197	=cut
149		198
150	sub async(&@) {	199	sub async(&@) {
151	my $pid = new Coro @_;	200	my $pid = new Coro @_;
152	$manager->ready; # this ensures that the stack is cloned from the manager
153	$pid->ready;	201	$pid->ready;
154	$pid;	202	$pid
155	}	203	}
156		204
157	=item schedule	205	=item schedule
158		206
159	Calls the scheduler. Please note that the current process will not be put	207	Calls the scheduler. Please note that the current coroutine will not be put
160	into the ready queue, so calling this function usually means you will	208	into the ready queue, so calling this function usually means you will
161	never be called again.	209	never be called again unless something else (e.g. an event handler) calls
		210	ready.
162		211
163	=cut	212	The canonical way to wait on external events is this:
		213
		214	{
		215	# remember current coroutine
		216	my $current = $Coro::current;
		217
		218	# register a hypothetical event handler
		219	on_event_invoke sub {
		220	# wake up sleeping coroutine
		221	$current->ready;
		222	undef $current;
		223	};
		224
		225	# call schedule until event occured.
		226	# in case we are woken up for other reasons
		227	# (current still defined), loop.
		228	Coro::schedule while $current;
		229	}
164		230
165	=item cede	231	=item cede
166		232
167	"Cede" to other processes. This function puts the current process into the	233	"Cede" to other coroutines. This function puts the current coroutine into the
168	ready queue and calls C<schedule>, which has the effect of giving up the	234	ready queue and calls C<schedule>, which has the effect of giving up the
169	current "timeslice" to other coroutines of the same or higher priority.	235	current "timeslice" to other coroutines of the same or higher priority.
170		236
171	=cut
172
173	=item terminate	237	=item terminate [arg...]
174		238
175	Terminates the current process.	239	Terminates the current coroutine with the given status values (see L<cancel>).
176
177	Future versions of this function will allow result arguments.
178		240
179	=cut	241	=cut
180		242
181	sub terminate {	243	sub terminate {
182	$current->cancel;	244	$current->cancel (@_);
183	&schedule;
184	die; # NORETURN
185	}	245	}
186		246
187	=back	247	=back
188		248
189	# dynamic methods	249	# dynamic methods
190		250
191	=head2 PROCESS METHODS	251	=head2 COROUTINE METHODS
192		252
193	These are the methods you can call on process objects.	253	These are the methods you can call on coroutine objects.
194		254
195	=over 4	255	=over 4
196		256
197	=item new Coro \&sub [, @args...]	257	=item new Coro \&sub [, @args...]
198		258
199	Create a new process and return it. When the sub returns the process	259	Create a new coroutine and return it. When the sub returns the coroutine
200	automatically terminates. To start the process you must first put it into	260	automatically terminates as if C<terminate> with the returned values were
		261	called. To make the coroutine run you must first put it into the ready queue
201	the ready queue by calling the ready method.	262	by calling the ready method.
202		263
203	The coderef you submit MUST NOT be a closure that refers to variables	264	Calling C<exit> in a coroutine will not work correctly, so do not do that.
204	in an outer scope. This does NOT work. Pass arguments into it instead.
205		265
206	=cut	266	=cut
207		267
208	sub _newcoro {	268	sub _run_coro {
209	terminate &{+shift};	269	terminate &{+shift};
210	}	270	}
211		271
212	sub new {	272	sub new {
213	my $class = shift;	273	my $class = shift;
214	bless {
215	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
216	}, $class;
217	}
218		274
219	=item $process->ready	275	$class->SUPER::new (\&_run_coro, @_)
		276	}
220		277
221	Put the current process into the ready queue.	278	=item $success = $coroutine->ready
222		279
223	=cut	280	Put the given coroutine into the ready queue (according to it's priority)
		281	and return true. If the coroutine is already in the ready queue, do nothing
		282	and return false.
224		283
225	=item $process->cancel	284	=item $is_ready = $coroutine->is_ready
226		285
227	Like C<terminate>, but terminates the specified process instead.	286	Return wether the coroutine is currently the ready queue or not,
		287
		288	=item $coroutine->cancel (arg...)
		289
		290	Terminates the given coroutine and makes it return the given arguments as
		291	status (default: the empty list).
228		292
229	=cut	293	=cut
230		294
231	sub cancel {	295	sub cancel {
		296	my $self = shift;
		297	$self->{status} = [@_];
232	push @destroy, $_[0];	298	push @destroy, $self;
233	$manager->ready;	299	$manager->ready;
234	&schedule if $current == $_[0];	300	&schedule if $current == $self;
235	}	301	}
236		302
		303	=item $coroutine->join
		304
		305	Wait until the coroutine terminates and return any values given to the
		306	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		307	from multiple coroutine.
		308
		309	=cut
		310
		311	sub join {
		312	my $self = shift;
		313	unless ($self->{status}) {
		314	push @{$self->{join}}, $current;
		315	&schedule;
		316	}
		317	wantarray ? @{$self->{status}} : $self->{status}[0];
		318	}
		319
237	=item $oldprio = $process->prio($newprio)	320	=item $oldprio = $coroutine->prio ($newprio)
238		321
239	Sets the priority of the process. Higher priority processes get run before	322	Sets (or gets, if the argument is missing) the priority of the
240	lower priority processes. Priorities are smalled signed integer (currently	323	coroutine. Higher priority coroutines get run before lower priority
		324	coroutines. Priorities are small signed integers (currently -4 .. +3),
241	-4 .. +3), that you can refer to using PRIO_xxx constants (use the import	325	that you can refer to using PRIO_xxx constants (use the import tag :prio
242	tag :prio to get then):	326	to get then):
243		327
244	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	328	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
245	3 > 1 > 0 > -1 > -3 > -4	329	3 > 1 > 0 > -1 > -3 > -4
246		330
247	# set priority to HIGH	331	# set priority to HIGH
248	current->prio(PRIO_HIGH);	332	current->prio(PRIO_HIGH);
249		333
250	The idle coroutine ($Coro::idle) always has a lower priority than any	334	The idle coroutine ($Coro::idle) always has a lower priority than any
251	existing coroutine.	335	existing coroutine.
252		336
253	Changing the priority of the current process will take effect immediately,	337	Changing the priority of the current coroutine will take effect immediately,
254	but changing the priority of processes in the ready queue (but not	338	but changing the priority of coroutines in the ready queue (but not
255	running) will only take effect after the next schedule (of that	339	running) will only take effect after the next schedule (of that
256	process). This is a bug that will be fixed in some future version.	340	coroutine). This is a bug that will be fixed in some future version.
257		341
258	=cut
259
260	sub prio {
261	my $old = $_[0]{prio};
262	$_[0]{prio} = $_[1] if @_ > 1;
263	$old;
264	}
265
266	=item $newprio = $process->nice($change)	342	=item $newprio = $coroutine->nice ($change)
267		343
268	Similar to C<prio>, but subtract the given value from the priority (i.e.	344	Similar to C<prio>, but subtract the given value from the priority (i.e.
269	higher values mean lower priority, just as in unix).	345	higher values mean lower priority, just as in unix).
270		346
271	=cut	347	=item $olddesc = $coroutine->desc ($newdesc)
272		348
273	sub nice {	349	Sets (or gets in case the argument is missing) the description for this
274	$_[0]{prio} -= $_[1];	350	coroutine. This is just a free-form string you can associate with a coroutine.
		351
		352	=cut
		353
		354	sub desc {
		355	my $old = $_[0]{desc};
		356	$_[0]{desc} = $_[1] if @_ > 1;
		357	$old;
275	}	358	}
276		359
277	=back	360	=back
278		361
		362	=head2 GLOBAL FUNCTIONS
		363
		364	=over 4
		365
		366	=item Coro::nready
		367
		368	Returns the number of coroutines that are currently in the ready state,
		369	i.e. that can be swicthed to. The value C<0> means that the only runnable
		370	coroutine is the currently running one, so C<cede> would have no effect,
		371	and C<schedule> would cause a deadlock unless there is an idle handler
		372	that wakes up some coroutines.
		373
		374	=item unblock_sub { ... }
		375
		376	This utility function takes a BLOCK or code reference and "unblocks" it,
		377	returning the new coderef. This means that the new coderef will return
		378	immediately without blocking, returning nothing, while the original code
		379	ref will be called (with parameters) from within its own coroutine.
		380
		381	The reason this fucntion exists is that many event libraries (such as the
		382	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		383	of thread-safety). This means you must not block within event callbacks,
		384	otherwise you might suffer from crashes or worse.
		385
		386	This function allows your callbacks to block by executing them in another
		387	coroutine where it is safe to block. One example where blocking is handy
		388	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		389	disk.
		390
		391	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		392	creating event callbacks that want to block.
		393
		394	=cut
		395
		396	our @unblock_pool;
		397	our @unblock_queue;
		398	our $UNBLOCK_POOL_SIZE = 2;
		399
		400	sub unblock_handler_ {
		401	while () {
		402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		403	$cb->(@arg);
		404
		405	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		406	push @unblock_pool, $Coro::current;
		407	schedule;
		408	}
		409	}
		410
		411	our $unblock_scheduler = async {
		412	while () {
		413	while (my $cb = pop @unblock_queue) {
		414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		415	$handler->{arg} = $cb;
		416	$handler->ready;
		417	cede;
		418	}
		419
		420	schedule;
		421	}
		422	};
		423
		424	sub unblock_sub(&) {
		425	my $cb = shift;
		426
		427	sub {
		428	push @unblock_queue, [$cb, @_];
		429	$unblock_scheduler->ready;
		430	}
		431	}
		432
		433	=back
		434
279	=cut	435	=cut
280		436
281	1;	437	1;
282		438
283	=head1 BUGS/LIMITATIONS	439	=head1 BUGS/LIMITATIONS
284		440
285	- you must make very sure that no coro is still active on global destruction.	441	- you must make very sure that no coro is still active on global
286	very bad things might happen otherwise (usually segfaults).	442	destruction. very bad things might happen otherwise (usually segfaults).
		443
287	- this module is not thread-safe. You must only ever use this module from	444	- this module is not thread-safe. You should only ever use this module
288	the same thread (this requirement might be loosened in the future to	445	from the same thread (this requirement might be losened in the future
289	allow per-thread schedulers, but Coro::State does not yet allow this).	446	to allow per-thread schedulers, but Coro::State does not yet allow
		447	this).
290		448
291	=head1 SEE ALSO	449	=head1 SEE ALSO
292		450
293	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	451	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
294	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,	452
295	L<Coro::Handle>, L<Coro::Socket>.	453	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		454
		455	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		456
		457	Embedding: L<Coro:MakeMaker>
296		458
297	=head1 AUTHOR	459	=head1 AUTHOR
298		460
299	Marc Lehmann <pcg@goof.com>	461	Marc Lehmann <schmorp@schmorp.de>
300	http://www.goof.com/pcg/marc/	462	http://home.schmorp.de/
301		463
302	=cut	464	=cut
303		465

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Comparing Coro/Coro.pm (file contents): Revision 1.35 by root, Mon Sep 24 00:16:30 2001 UTC vs. Revision 1.100 by root, Tue Dec 12 13:56:45 2006 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.35 by root, Mon Sep 24 00:16:30 2001 UTC vs.
Revision 1.100 by root, Tue Dec 12 13:56:45 2006 UTC