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Revision 1.9 by root, Sun Jul 15 02:35:52 2001 UTC vs.
Revision 1.58 by pcg, Fri Feb 13 23:17:41 2004 UTC

… …
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 yield; 19 cede;
20 20
21=head1 DESCRIPTION 21=head1 DESCRIPTION
22 22
23This module collection manages coroutines. Coroutines are similar to
24threads but don't run in parallel.
25
26In this module, coroutines are defined as "callchain + lexical variables
27+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
28callchain, it's own set of lexicals and it's own set of perl's most
29important global variables.
30
23=cut 31=cut
24 32
25package Coro; 33package Coro;
26 34
35BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") }
36
27use Coro::State; 37use Coro::State;
28 38
39use vars qw($idle $main $current);
40
29use base Exporter; 41use base Exporter;
30 42
31$VERSION = 0.04; 43$VERSION = 0.95;
32 44
33@EXPORT = qw(async yield schedule); 45@EXPORT = qw(async cede schedule terminate current);
34@EXPORT_OK = qw($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}};
35 50
36{ 51{
37 use subs 'async';
38
39 my @async; 52 my @async;
53 my $init;
40 54
41 # this way of handling attributes simply is NOT scalable ;() 55 # this way of handling attributes simply is NOT scalable ;()
42 sub import { 56 sub import {
43 Coro->export_to_level(1, @_); 57 Coro->export_to_level(1, @_);
44 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 58 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
… …
46 my ($package, $ref) = (shift, shift); 60 my ($package, $ref) = (shift, shift);
47 my @attrs; 61 my @attrs;
48 for (@_) { 62 for (@_) {
49 if ($_ eq "Coro") { 63 if ($_ eq "Coro") {
50 push @async, $ref; 64 push @async, $ref;
65 unless ($init++) {
66 eval q{
67 sub INIT {
68 &async(pop @async) while @async;
69 }
70 };
71 }
51 } else { 72 } else {
52 push @attrs, @_; 73 push @attrs, $_;
53 } 74 }
54 } 75 }
55 return $old ? $old->($package, $name, @attrs) : @attrs; 76 return $old ? $old->($package, $ref, @attrs) : @attrs;
56 }; 77 };
57 } 78 }
58 79
59 sub INIT {
60 async pop @async while @async;
61 }
62} 80}
81
82=over 4
63 83
64=item $main 84=item $main
65 85
66This coroutine represents the main program. 86This coroutine represents the main program.
67 87
68=cut 88=cut
69 89
70our $main = new Coro; 90$main = new Coro;
71 91
72=item $current 92=item $current (or as function: current)
73 93
74The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 94The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
75 95
76=cut 96=cut
77 97
78# maybe some other module used Coro::Specific before... 98# maybe some other module used Coro::Specific before...
79if ($current) { 99if ($current) {
80 $main->{specific} = $current->{specific}; 100 $main->{specific} = $current->{specific};
81} 101}
82 102
83our $current = $main; 103$current = $main;
104
105sub current() { $current }
84 106
85=item $idle 107=item $idle
86 108
87The coroutine to switch to when no other coroutine is running. The default 109The coroutine to switch to when no other coroutine is running. The default
88implementation prints "FATAL: deadlock detected" and exits. 110implementation prints "FATAL: deadlock detected" and exits.
89 111
90=cut 112=cut
91 113
92# should be done using priorities :( 114# should be done using priorities :(
93our $idle = new Coro sub { 115$idle = new Coro sub {
94 print STDERR "FATAL: deadlock detected\n"; 116 print STDERR "FATAL: deadlock detected\n";
95 exit(51); 117 exit(51);
96}; 118};
97 119
98# we really need priorities... 120# this coroutine is necessary because a coroutine
99my @ready = (); # the ready queue. hehe, rather broken ;) 121# cannot destroy itself.
122my @destroy;
123my $manager;
124$manager = new Coro sub {
125 while () {
126 # by overwriting the state object with the manager we destroy it
127 # while still being able to schedule this coroutine (in case it has
128 # been readied multiple times. this is harmless since the manager
129 # can be called as many times as neccessary and will always
130 # remove itself from the runqueue
131 while (@destroy) {
132 my $coro = pop @destroy;
133 $coro->{status} ||= [];
134 $_->ready for @{delete $coro->{join} || []};
135 $coro->{_coro_state} = $manager->{_coro_state};
136 }
137 &schedule;
138 }
139};
100 140
101# static methods. not really. 141# static methods. not really.
102 142
143=back
144
103=head2 STATIC METHODS 145=head2 STATIC METHODS
104 146
105Static methods are actually functions that operate on the current process only. 147Static methods are actually functions that operate on the current process only.
106 148
107=over 4 149=over 4
108 150
109=item async { ... }; 151=item async { ... } [@args...]
110 152
111Create a new asynchronous process and return it's process object 153Create a new asynchronous process and return it's process object
112(usually unused). When the sub returns the new process is automatically 154(usually unused). When the sub returns the new process is automatically
113terminated. 155terminated.
114 156
115=cut 157 # create a new coroutine that just prints its arguments
158 async {
159 print "@_\n";
160 } 1,2,3,4;
116 161
162=cut
163
117sub async(&) { 164sub async(&@) {
118 (new Coro $_[0])->ready; 165 my $pid = new Coro @_;
166 $manager->ready; # this ensures that the stack is cloned from the manager
167 $pid->ready;
168 $pid;
119} 169}
120 170
121=item schedule 171=item schedule
122 172
123Calls the scheduler. Please note that the current process will not be put 173Calls the scheduler. Please note that the current process will not be put
124into the ready queue, so calling this function usually means you will 174into the ready queue, so calling this function usually means you will
125never be called again. 175never be called again.
126 176
127=cut 177=cut
128 178
129my $prev;
130
131sub schedule {
132 # should be done using priorities :(
133 ($prev, $current) = ($current, shift @ready || $idle);
134 Coro::State::transfer($prev, $current);
135}
136
137=item yield 179=item cede
138 180
139Yield to other processes. This function puts the current process into the 181"Cede" to other processes. This function puts the current process into the
140ready queue and calls C<schedule>. 182ready queue and calls C<schedule>, which has the effect of giving up the
183current "timeslice" to other coroutines of the same or higher priority.
141 184
142=cut 185=cut
143 186
144sub yield { 187=item terminate [arg...]
188
189Terminates the current process.
190
191Future versions of this function will allow result arguments.
192
193=cut
194
195sub terminate {
196 $current->{status} = [@_];
145 $current->ready; 197 $current->cancel;
146 &schedule; 198 &schedule;
147} 199 die; # NORETURN
148
149=item terminate
150
151Terminates the current process.
152
153=cut
154
155sub terminate {
156 &schedule;
157} 200}
158 201
159=back 202=back
160 203
161# dynamic methods 204# dynamic methods
… …
164 207
165These are the methods you can call on process objects. 208These are the methods you can call on process objects.
166 209
167=over 4 210=over 4
168 211
169=item new Coro \&sub; 212=item new Coro \&sub [, @args...]
170 213
171Create a new process and return it. When the sub returns the process 214Create a new process and return it. When the sub returns the process
172automatically terminates. To start the process you must first put it into 215automatically terminates as if C<terminate> with the returned values were
216called. To make the process run you must first put it into the ready queue
173the ready queue by calling the ready method. 217by calling the ready method.
174 218
175=cut 219=cut
220
221sub _newcoro {
222 terminate &{+shift};
223}
176 224
177sub new { 225sub new {
178 my $class = shift; 226 my $class = shift;
179 my $proc = $_[0];
180 bless { 227 bless {
181 _coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc), 228 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
182 }, $class; 229 }, $class;
183} 230}
184 231
185=item $process->ready 232=item $process->ready
186 233
187Put the current process into the ready queue. 234Put the given process into the ready queue.
188 235
189=cut 236=cut
190 237
191sub ready { 238=item $process->cancel
239
240Like C<terminate>, but terminates the specified process instead.
241
242=cut
243
244sub cancel {
192 push @ready, $_[0]; 245 push @destroy, $_[0];
246 $manager->ready;
247 &schedule if $current == $_[0];
248}
249
250=item $process->join
251
252Wait until the coroutine terminates and return any values given to the
253C<terminate> function. C<join> can be called multiple times from multiple
254processes.
255
256=cut
257
258sub join {
259 my $self = shift;
260 unless ($self->{status}) {
261 push @{$self->{join}}, $current;
262 &schedule;
263 }
264 wantarray ? @{$self->{status}} : $self->{status}[0];
265}
266
267=item $oldprio = $process->prio($newprio)
268
269Sets (or gets, if the argument is missing) the priority of the
270process. Higher priority processes get run before lower priority
271processes. Priorities are small signed integers (currently -4 .. +3),
272that you can refer to using PRIO_xxx constants (use the import tag :prio
273to get then):
274
275 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
276 3 > 1 > 0 > -1 > -3 > -4
277
278 # set priority to HIGH
279 current->prio(PRIO_HIGH);
280
281The idle coroutine ($Coro::idle) always has a lower priority than any
282existing coroutine.
283
284Changing the priority of the current process will take effect immediately,
285but changing the priority of processes in the ready queue (but not
286running) will only take effect after the next schedule (of that
287process). This is a bug that will be fixed in some future version.
288
289=cut
290
291sub prio {
292 my $old = $_[0]{prio};
293 $_[0]{prio} = $_[1] if @_ > 1;
294 $old;
295}
296
297=item $newprio = $process->nice($change)
298
299Similar to C<prio>, but subtract the given value from the priority (i.e.
300higher values mean lower priority, just as in unix).
301
302=cut
303
304sub nice {
305 $_[0]{prio} -= $_[1];
306}
307
308=item $olddesc = $process->desc($newdesc)
309
310Sets (or gets in case the argument is missing) the description for this
311process. This is just a free-form string you can associate with a process.
312
313=cut
314
315sub desc {
316 my $old = $_[0]{desc};
317 $_[0]{desc} = $_[1] if @_ > 1;
318 $old;
193} 319}
194 320
195=back 321=back
196 322
197=cut 323=cut
198 324
1991; 3251;
200 326
327=head1 BUGS/LIMITATIONS
328
329 - you must make very sure that no coro is still active on global
330 destruction. very bad things might happen otherwise (usually segfaults).
331
332 - this module is not thread-safe. You should only ever use this module
333 from the same thread (this requirement might be losened in the future
334 to allow per-thread schedulers, but Coro::State does not yet allow
335 this).
336
201=head1 SEE ALSO 337=head1 SEE ALSO
202 338
203L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 339L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
204L<Coro::Signal>, L<Coro::State>. 340L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,
341L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>.
205 342
206=head1 AUTHOR 343=head1 AUTHOR
207 344
208 Marc Lehmann <pcg@goof.com> 345 Marc Lehmann <pcg@goof.com>
209 http://www.goof.com/pcg/marc/ 346 http://www.goof.com/pcg/marc/

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