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Revision 1.23 by root, Mon Jul 23 04:23:32 2001 UTC vs.
Revision 1.42 by root, Tue Nov 6 20:37:20 2001 UTC

… …
19 cede; 19 cede;
20 20
21=head1 DESCRIPTION 21=head1 DESCRIPTION
22 22
23This module collection manages coroutines. Coroutines are similar to 23This module collection manages coroutines. Coroutines are similar to
24Threads but don't run in parallel. 24threads but don't run in parallel.
25
26This module is still experimental, see the BUGS section below.
27 25
28In this module, coroutines are defined as "callchain + lexical variables 26In this module, coroutines are defined as "callchain + lexical variables
29+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own 27+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35no warnings qw(uninitialized);
36
37use Coro::State; 37use Coro::State;
38 38
39use base Exporter; 39use base Exporter;
40 40
41$VERSION = 0.10; 41$VERSION = 0.52;
42 42
43@EXPORT = qw(async cede schedule terminate current); 43@EXPORT = qw(async cede schedule terminate current);
44@EXPORT_OK = qw($current); 44%EXPORT_TAGS = (
45 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
46);
47@EXPORT_OK = @{$EXPORT_TAGS{prio}};
45 48
46{ 49{
47 my @async; 50 my @async;
51 my $init;
48 52
49 # this way of handling attributes simply is NOT scalable ;() 53 # this way of handling attributes simply is NOT scalable ;()
50 sub import { 54 sub import {
51 Coro->export_to_level(1, @_); 55 Coro->export_to_level(1, @_);
52 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 56 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
… …
54 my ($package, $ref) = (shift, shift); 58 my ($package, $ref) = (shift, shift);
55 my @attrs; 59 my @attrs;
56 for (@_) { 60 for (@_) {
57 if ($_ eq "Coro") { 61 if ($_ eq "Coro") {
58 push @async, $ref; 62 push @async, $ref;
63 unless ($init++) {
64 eval q{
65 sub INIT {
66 &async(pop @async) while @async;
67 }
68 };
69 }
59 } else { 70 } else {
60 push @attrs, $_; 71 push @attrs, $_;
61 } 72 }
62 } 73 }
63 return $old ? $old->($package, $ref, @attrs) : @attrs; 74 return $old ? $old->($package, $ref, @attrs) : @attrs;
64 }; 75 };
65 } 76 }
66 77
67 sub INIT {
68 &async(pop @async) while @async;
69 }
70} 78}
71 79
72=item $main 80=item $main
73 81
74This coroutine represents the main program. 82This coroutine represents the main program.
… …
103our $idle = new Coro sub { 111our $idle = new Coro sub {
104 print STDERR "FATAL: deadlock detected\n"; 112 print STDERR "FATAL: deadlock detected\n";
105 exit(51); 113 exit(51);
106}; 114};
107 115
108# we really need priorities... 116# this coroutine is necessary because a coroutine
109my @ready; # the ready queue. hehe, rather broken ;) 117# cannot destroy itself.
118my @destroy;
119my $manager;
120$manager = new Coro sub {
121 while() {
122 # by overwriting the state object with the manager we destroy it
123 # while still being able to schedule this coroutine (in case it has
124 # been readied multiple times. this is harmless since the manager
125 # can be called as many times as neccessary and will always
126 # remove itself from the runqueue
127 while (@destroy) {
128 my $coro = pop @destroy;
129 $coro->{status} ||= [];
130 $_->ready for @{delete $coro->{join} || []};
131 $coro->{_coro_state} = $manager->{_coro_state};
132 }
133 &schedule;
134 }
135};
110 136
111# static methods. not really. 137# static methods. not really.
112 138
113=head2 STATIC METHODS 139=head2 STATIC METHODS
114 140
… …
132 158
133=cut 159=cut
134 160
135sub async(&@) { 161sub async(&@) {
136 my $pid = new Coro @_; 162 my $pid = new Coro @_;
163 $manager->ready; # this ensures that the stack is cloned from the manager
137 $pid->ready; 164 $pid->ready;
138 $pid; 165 $pid;
139} 166}
140 167
141=item schedule 168=item schedule
… …
144into the ready queue, so calling this function usually means you will 171into the ready queue, so calling this function usually means you will
145never be called again. 172never be called again.
146 173
147=cut 174=cut
148 175
149my $prev;
150
151sub schedule {
152 # should be done using priorities :(
153 ($prev, $current) = ($current, shift @ready || $idle);
154 Coro::State::transfer($prev, $current);
155}
156
157=item cede 176=item cede
158 177
159"Cede" to other processes. This function puts the current process into the 178"Cede" to other processes. This function puts the current process into the
160ready queue and calls C<schedule>, which has the effect of giving up the 179ready queue and calls C<schedule>, which has the effect of giving up the
161current "timeslice" to other coroutines of the same or higher priority. 180current "timeslice" to other coroutines of the same or higher priority.
162 181
163=cut 182=cut
164 183
165sub cede { 184=item terminate [arg...]
185
186Terminates the current process.
187
188Future versions of this function will allow result arguments.
189
190=cut
191
192sub terminate {
193 $current->{status} = [@_];
166 $current->ready; 194 $current->cancel;
167 &schedule; 195 &schedule;
168}
169
170=item terminate
171
172Terminates the current process.
173
174Future versions of this function will allow result arguments.
175
176=cut
177
178# this coroutine is necessary because a coroutine
179# cannot destroy itself.
180my @destroy;
181my $terminate = new Coro sub {
182 while() {
183 delete ((pop @destroy)->{_coro_state}) while @destroy;
184 &schedule;
185 }
186};
187
188sub terminate {
189 push @destroy, $current;
190 $terminate->ready;
191 &schedule;
192 # NORETURN 196 die; # NORETURN
193} 197}
194 198
195=back 199=back
196 200
197# dynamic methods 201# dynamic methods
… …
203=over 4 207=over 4
204 208
205=item new Coro \&sub [, @args...] 209=item new Coro \&sub [, @args...]
206 210
207Create a new process and return it. When the sub returns the process 211Create a new process and return it. When the sub returns the process
208automatically terminates. To start the process you must first put it into 212automatically terminates as if C<terminate> with the returned values were
213called. To make the process run you must first put it into the ready queue
209the ready queue by calling the ready method. 214by calling the ready method.
210
211The coderef you submit MUST NOT be a closure that refers to variables
212in an outer scope. This does NOT work. Pass arguments into it instead.
213 215
214=cut 216=cut
215 217
216sub _newcoro { 218sub _newcoro {
217 terminate &{+shift}; 219 terminate &{+shift};
… …
224 }, $class; 226 }, $class;
225} 227}
226 228
227=item $process->ready 229=item $process->ready
228 230
229Put the current process into the ready queue. 231Put the given process into the ready queue.
230 232
231=cut 233=cut
232 234
233sub ready { 235=item $process->cancel
236
237Like C<terminate>, but terminates the specified process instead.
238
239=cut
240
241sub cancel {
234 push @ready, $_[0]; 242 push @destroy, $_[0];
243 $manager->ready;
244 &schedule if $current == $_[0];
245}
246
247=item $process->join
248
249Wait until the coroutine terminates and return any values given to the
250C<terminate> function. C<join> can be called multiple times from multiple
251processes.
252
253=cut
254
255sub join {
256 my $self = shift;
257 unless ($self->{status}) {
258 push @{$self->{join}}, $current;
259 &schedule;
260 }
261 wantarray ? @{$self->{status}} : $self->{status}[0];
262}
263
264=item $oldprio = $process->prio($newprio)
265
266Sets (or gets, if the argument is missing) the priority of the
267process. Higher priority processes get run before lower priority
268processes. Priorities are smalled signed integer (currently -4 .. +3),
269that you can refer to using PRIO_xxx constants (use the import tag :prio
270to get then):
271
272 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
273 3 > 1 > 0 > -1 > -3 > -4
274
275 # set priority to HIGH
276 current->prio(PRIO_HIGH);
277
278The idle coroutine ($Coro::idle) always has a lower priority than any
279existing coroutine.
280
281Changing the priority of the current process will take effect immediately,
282but changing the priority of processes in the ready queue (but not
283running) will only take effect after the next schedule (of that
284process). This is a bug that will be fixed in some future version.
285
286=cut
287
288sub prio {
289 my $old = $_[0]{prio};
290 $_[0]{prio} = $_[1] if @_ > 1;
291 $old;
292}
293
294=item $newprio = $process->nice($change)
295
296Similar to C<prio>, but subtract the given value from the priority (i.e.
297higher values mean lower priority, just as in unix).
298
299=cut
300
301sub nice {
302 $_[0]{prio} -= $_[1];
303}
304
305=item $olddesc = $process->desc($newdesc)
306
307Sets (or gets in case the argument is missing) the description for this
308process. This is just a free-form string you can associate with a process.
309
310=cut
311
312sub desc {
313 my $old = $_[0]{desc};
314 $_[0]{desc} = $_[1] if @_ > 1;
315 $old;
235} 316}
236 317
237=back 318=back
238 319
239=cut 320=cut
240 321
2411; 3221;
242 323
243=head1 BUGS/LIMITATIONS 324=head1 BUGS/LIMITATIONS
244 325
245 - could be faster, especially when the core would introduce special 326 - you must make very sure that no coro is still active on global destruction.
246 support for coroutines (like it does for threads). 327 very bad things might happen otherwise (usually segfaults).
247 - there is still a memleak on coroutine termination that I could not
248 identify. Could be as small as a single SV.
249 - this module is not well-tested.
250 - if variables or arguments "disappear" (become undef) or become
251 corrupted please contact the author so he cen iron out the
252 remaining bugs.
253 - this module is not thread-safe. You must only ever use this module from 328 - this module is not thread-safe. You should only ever use this module from
254 the same thread (this requirement might be loosened in the future to 329 the same thread (this requirement might be loosened in the future to
255 allow per-thread schedulers, but Coro::State does not yet allow this). 330 allow per-thread schedulers, but Coro::State does not yet allow this).
256 331
257=head1 SEE ALSO 332=head1 SEE ALSO
258 333
259L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 334L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
260L<Coro::Signal>, L<Coro::State>, L<Coro::Event>. 335L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
336L<Coro::Handle>, L<Coro::Socket>.
261 337
262=head1 AUTHOR 338=head1 AUTHOR
263 339
264 Marc Lehmann <pcg@goof.com> 340 Marc Lehmann <pcg@goof.com>
265 http://www.goof.com/pcg/marc/ 341 http://www.goof.com/pcg/marc/

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