[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 1.86 by root, Sat Nov 25 01:14:11 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; $manager = new Coro sub {
		139	while () {
		140	# by overwriting the state object with the manager we destroy it
		141	# while still being able to schedule this coroutine (in case it has
		142	# been readied multiple times. this is harmless since the manager
		143	# can be called as many times as neccessary and will always
		144	# remove itself from the runqueue
		145	while (@destroy) {
		146	my $coro = pop @destroy;
		147	$coro->{status} \|\|= [];
		148	$_->ready for @{delete $coro->{join} \|\| []};
		149
		150	# the next line destroys the coro state, but keeps the
		151	# process itself intact (we basically make it a zombie
		152	# process that always runs the manager thread, so it's possible
		153	# to transfer() to this process).
		154	$coro->_clone_state_from ($manager);
		155	}
		156	&schedule;
		157	}
		158	};
126		159
127	# static methods. not really.	160	# static methods. not really.
		161
		162	=back
128		163
129	=head2 STATIC METHODS	164	=head2 STATIC METHODS
130		165
131	Static methods are actually functions that operate on the current process only.	166	Static methods are actually functions that operate on the current process only.
132		167
…		…
135	=item async { ... } [@args...]	170	=item async { ... } [@args...]
136		171
137	Create a new asynchronous process and return it's process object	172	Create a new asynchronous process and return it's process object
138	(usually unused). When the sub returns the new process is automatically	173	(usually unused). When the sub returns the new process is automatically
139	terminated.	174	terminated.
		175
		176	When the coroutine dies, the program will exit, just as in the main
		177	program.
140		178
141	# create a new coroutine that just prints its arguments	179	# create a new coroutine that just prints its arguments
142	async {	180	async {
143	print "@_\n";	181	print "@_\n";
144	} 1,2,3,4;	182	} 1,2,3,4;
145		183
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	184	=cut
150		185
151	sub async(&@) {	186	sub async(&@) {
152	my $pid = new Coro @_;	187	my $pid = new Coro @_;
153	$pid->ready;	188	$pid->ready;
154	$pid;	189	$pid
155	}	190	}
156		191
157	=item schedule	192	=item schedule
158		193
159	Calls the scheduler. Please note that the current process will not be put	194	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	195	into the ready queue, so calling this function usually means you will
161	never be called again.	196	never be called again.
162		197
163	=cut	198	=cut
164		199
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	200	=item cede
174		201
175	"Cede" to other processes. This function puts the current process into the	202	"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	203	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.	204	current "timeslice" to other coroutines of the same or higher priority.
178		205
179	=cut	206	=cut
180		207
181	sub cede {
182	$current->ready;
183	&schedule;
184	}
185
186	=item terminate	208	=item terminate [arg...]
187		209
188	Terminates the current process.	210	Terminates the current process with the given status values (see L<cancel>).
189
190	Future versions of this function will allow result arguments.
191		211
192	=cut	212	=cut
193		213
194	sub terminate {	214	sub terminate {
195	my $self = $current;	215	$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	}	216	}
202		217
203	=back	218	=back
204		219
205	# dynamic methods	220	# dynamic methods
…		…
211	=over 4	226	=over 4
212		227
213	=item new Coro \&sub [, @args...]	228	=item new Coro \&sub [, @args...]
214		229
215	Create a new process and return it. When the sub returns the process	230	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	231	automatically terminates as if C<terminate> with the returned values were
		232	called. To make the process run you must first put it into the ready queue
217	the ready queue by calling the ready method.	233	by calling the ready method.
218		234
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	235	=cut
223		236
224	sub _newcoro {	237	sub _new_coro {
		238	$current->_clear_idle_sp; # (re-)set the idle sp on the following cede
		239	_set_cede_self; # ensures that cede cede's us first
		240	cede;
225	terminate &{+shift};	241	terminate &{+shift};
226	}	242	}
227		243
228	sub new {	244	sub new {
229	my $class = shift;	245	my $class = shift;
230	bless {	246
231	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),	247	$class->SUPER::new (\&_new_coro, @_)
232	}, $class;
233	}	248	}
234		249
235	=item $process->ready	250	=item $process->ready
236		251
237	Put the current process into the ready queue.	252	Put the given process into the ready queue.
238		253
239	=cut	254	=cut
240		255
241	sub ready {	256	=item $process->cancel (arg...)
242	push @ready, $_[0];	257
		258	Terminates the given process and makes it return the given arguments as
		259	status (default: the empty list).
		260
		261	=cut
		262
		263	sub cancel {
		264	my $self = shift;
		265	$self->{status} = [@_];
		266	push @destroy, $self;
		267	$manager->ready;
		268	&schedule if $current == $self;
		269	}
		270
		271	=item $process->join
		272
		273	Wait until the coroutine terminates and return any values given to the
		274	C<terminate> or C<cancel> functions. C<join> can be called multiple times
		275	from multiple processes.
		276
		277	=cut
		278
		279	sub join {
		280	my $self = shift;
		281	unless ($self->{status}) {
		282	push @{$self->{join}}, $current;
		283	&schedule;
		284	}
		285	wantarray ? @{$self->{status}} : $self->{status}[0];
		286	}
		287
		288	=item $oldprio = $process->prio ($newprio)
		289
		290	Sets (or gets, if the argument is missing) the priority of the
		291	process. Higher priority processes get run before lower priority
		292	processes. Priorities are small signed integers (currently -4 .. +3),
		293	that you can refer to using PRIO_xxx constants (use the import tag :prio
		294	to get then):
		295
		296	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
		297	3 > 1 > 0 > -1 > -3 > -4
		298
		299	# set priority to HIGH
		300	current->prio(PRIO_HIGH);
		301
		302	The idle coroutine ($Coro::idle) always has a lower priority than any
		303	existing coroutine.
		304
		305	Changing the priority of the current process will take effect immediately,
		306	but changing the priority of processes in the ready queue (but not
		307	running) will only take effect after the next schedule (of that
		308	process). This is a bug that will be fixed in some future version.
		309
		310	=item $newprio = $process->nice ($change)
		311
		312	Similar to C<prio>, but subtract the given value from the priority (i.e.
		313	higher values mean lower priority, just as in unix).
		314
		315	=item $olddesc = $process->desc ($newdesc)
		316
		317	Sets (or gets in case the argument is missing) the description for this
		318	process. This is just a free-form string you can associate with a process.
		319
		320	=cut
		321
		322	sub desc {
		323	my $old = $_[0]{desc};
		324	$_[0]{desc} = $_[1] if @_ > 1;
		325	$old;
243	}	326	}
244		327
245	=back	328	=back
246		329
247	=cut	330	=cut
248		331
249	1;	332	1;
250		333
251	=head1 BUGS/LIMITATIONS	334	=head1 BUGS/LIMITATIONS
252		335
253	- could be faster, especially when the core would introduce special	336	- you must make very sure that no coro is still active on global
254	support for coroutines (like it does for threads).	337	destruction. very bad things might happen otherwise (usually segfaults).
255	- there is still a memleak on coroutine termination that I could not	338
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	339	- 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	340	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).	341	to allow per-thread schedulers, but Coro::State does not yet allow
		342	this).
264		343
265	=head1 SEE ALSO	344	=head1 SEE ALSO
266		345
267	L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,	346	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
268	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.	347
		348	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
		349
		350	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
		351
		352	Embedding: L<Coro:MakeMaker>
269		353
270	=head1 AUTHOR	354	=head1 AUTHOR
271		355
272	Marc Lehmann <pcg@goof.com>	356	Marc Lehmann <schmorp@schmorp.de>
273	http://www.goof.com/pcg/marc/	357	http://home.schmorp.de/
274		358
275	=cut	359	=cut
276		360

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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 1.86 by root, Sat Nov 25 01:14:11 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 1.86 by root, Sat Nov 25 01:14:11 2006 UTC