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Revision 1.36 by root, Mon Sep 24 01:36:20 2001 UTC vs.
Revision 1.65 by root, Tue Feb 22 19:51:58 2005 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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
37no warnings qw(uninitialized); 35BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") }
38 36
39use Coro::State; 37use Coro::State;
40 38
39use vars qw($idle $main $current);
40
41use base Exporter; 41use base Exporter;
42 42
43$VERSION = 0.5; 43$VERSION = 1.1;
44 44
45@EXPORT = qw(async cede schedule terminate current); 45@EXPORT = qw(async cede schedule terminate current);
46%EXPORT_TAGS = ( 46%EXPORT_TAGS = (
47 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 47 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48); 48);
77 }; 77 };
78 } 78 }
79 79
80} 80}
81 81
82=over 4
83
82=item $main 84=item $main
83 85
84This coroutine represents the main program. 86This coroutine represents the main program.
85 87
86=cut 88=cut
87 89
88our $main = new Coro; 90$main = new Coro;
89 91
90=item $current (or as function: current) 92=item $current (or as function: current)
91 93
92The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 94The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
93 95
96# maybe some other module used Coro::Specific before... 98# maybe some other module used Coro::Specific before...
97if ($current) { 99if ($current) {
98 $main->{specific} = $current->{specific}; 100 $main->{specific} = $current->{specific};
99} 101}
100 102
101our $current = $main; 103$current = $main;
102 104
103sub current() { $current } 105sub current() { $current }
104 106
105=item $idle 107=item $idle
106 108
108implementation prints "FATAL: deadlock detected" and exits. 110implementation prints "FATAL: deadlock detected" and exits.
109 111
110=cut 112=cut
111 113
112# should be done using priorities :( 114# should be done using priorities :(
113our $idle = new Coro sub { 115$idle = new Coro sub {
114 print STDERR "FATAL: deadlock detected\n"; 116 print STDERR "FATAL: deadlock detected\n";
115 exit(51); 117 exit(51);
116}; 118};
117 119
118# this coroutine is necessary because a coroutine 120# this coroutine is necessary because a coroutine
119# cannot destroy itself. 121# cannot destroy itself.
120my @destroy; 122my @destroy;
123my $manager;
121my $manager = new Coro sub { 124$manager = new Coro sub {
122 while() { 125 while () {
123 delete ((pop @destroy)->{_coro_state}) while @destroy; 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
136 # the next line destroys the _coro_state, but keeps the
137 # process itself intact (we basically make it a zombie
138 # process that always runs the manager thread, so it's possible
139 # to transfer() to this process).
140 $coro->{_coro_state} = $manager->{_coro_state};
141 }
124 &schedule; 142 &schedule;
125 } 143 }
126}; 144};
127 145
128# static methods. not really. 146# static methods. not really.
147
148=back
129 149
130=head2 STATIC METHODS 150=head2 STATIC METHODS
131 151
132Static methods are actually functions that operate on the current process only. 152Static methods are actually functions that operate on the current process only.
133 153
141 161
142 # create a new coroutine that just prints its arguments 162 # create a new coroutine that just prints its arguments
143 async { 163 async {
144 print "@_\n"; 164 print "@_\n";
145 } 1,2,3,4; 165 } 1,2,3,4;
146
147The coderef you submit MUST NOT be a closure that refers to variables
148in an outer scope. This does NOT work. Pass arguments into it instead.
149 166
150=cut 167=cut
151 168
152sub async(&@) { 169sub async(&@) {
153 my $pid = new Coro @_; 170 my $pid = new Coro @_;
170ready queue and calls C<schedule>, which has the effect of giving up the 187ready queue and calls C<schedule>, which has the effect of giving up the
171current "timeslice" to other coroutines of the same or higher priority. 188current "timeslice" to other coroutines of the same or higher priority.
172 189
173=cut 190=cut
174 191
175=item terminate 192=item terminate [arg...]
176 193
177Terminates the current process. 194Terminates the current process with the given status values (see L<cancel>).
178
179Future versions of this function will allow result arguments.
180 195
181=cut 196=cut
182 197
183sub terminate { 198sub terminate {
184 $current->cancel; 199 $current->cancel (@_);
185 &schedule;
186 die; # NORETURN
187} 200}
188 201
189=back 202=back
190 203
191# dynamic methods 204# dynamic methods
197=over 4 210=over 4
198 211
199=item new Coro \&sub [, @args...] 212=item new Coro \&sub [, @args...]
200 213
201Create 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
202automatically 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
203the ready queue by calling the ready method. 217by calling the ready method.
204
205The coderef you submit MUST NOT be a closure that refers to variables
206in an outer scope. This does NOT work. Pass arguments into it instead.
207 218
208=cut 219=cut
209 220
210sub _newcoro { 221sub _newcoro {
211 terminate &{+shift}; 222 terminate &{+shift};
218 }, $class; 229 }, $class;
219} 230}
220 231
221=item $process->ready 232=item $process->ready
222 233
223Put the current process into the ready queue. 234Put the given process into the ready queue.
224 235
225=cut 236=cut
226 237
227=item $process->cancel 238=item $process->cancel (arg...)
228 239
229Like C<terminate>, but terminates the specified process instead. 240Temrinates the given process and makes it return the given arguments as
241status (default: the empty list).
230 242
231=cut 243=cut
232 244
233sub cancel { 245sub cancel {
246 my $self = shift;
247 $self->{status} = [@_];
234 push @destroy, $_[0]; 248 push @destroy, $self;
235 $manager->ready; 249 $manager->ready;
236 &schedule if $current == $_[0]; 250 &schedule if $current == $self;
251}
252
253=item $process->join
254
255Wait until the coroutine terminates and return any values given to the
256C<terminate> or C<cancel> functions. C<join> can be called multiple times
257from multiple processes.
258
259=cut
260
261sub join {
262 my $self = shift;
263 unless ($self->{status}) {
264 push @{$self->{join}}, $current;
265 &schedule;
266 }
267 wantarray ? @{$self->{status}} : $self->{status}[0];
237} 268}
238 269
239=item $oldprio = $process->prio($newprio) 270=item $oldprio = $process->prio($newprio)
240 271
241Sets the priority of the process. Higher priority processes get run before 272Sets (or gets, if the argument is missing) the priority of the
273process. Higher priority processes get run before lower priority
242lower priority processes. Priorities are smalled signed integer (currently 274processes. Priorities are small signed integers (currently -4 .. +3),
243-4 .. +3), that you can refer to using PRIO_xxx constants (use the import 275that you can refer to using PRIO_xxx constants (use the import tag :prio
244tag :prio to get then): 276to get then):
245 277
246 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 278 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
247 3 > 1 > 0 > -1 > -3 > -4 279 3 > 1 > 0 > -1 > -3 > -4
248 280
249 # set priority to HIGH 281 # set priority to HIGH
274 306
275sub nice { 307sub nice {
276 $_[0]{prio} -= $_[1]; 308 $_[0]{prio} -= $_[1];
277} 309}
278 310
311=item $olddesc = $process->desc($newdesc)
312
313Sets (or gets in case the argument is missing) the description for this
314process. This is just a free-form string you can associate with a process.
315
316=cut
317
318sub desc {
319 my $old = $_[0]{desc};
320 $_[0]{desc} = $_[1] if @_ > 1;
321 $old;
322}
323
279=back 324=back
280 325
281=cut 326=cut
282 327
2831; 3281;
284 329
285=head1 BUGS/LIMITATIONS 330=head1 BUGS/LIMITATIONS
286 331
287 - you must make very sure that no coro is still active on global destruction. 332 - you must make very sure that no coro is still active on global
288 very bad things might happen otherwise (usually segfaults). 333 destruction. very bad things might happen otherwise (usually segfaults).
334
289 - this module is not thread-safe. You must only ever use this module from 335 - this module is not thread-safe. You should only ever use this module
290 the same thread (this requirement might be loosened in the future to 336 from the same thread (this requirement might be losened in the future
291 allow per-thread schedulers, but Coro::State does not yet allow this). 337 to allow per-thread schedulers, but Coro::State does not yet allow
338 this).
292 339
293=head1 SEE ALSO 340=head1 SEE ALSO
294 341
295L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 342L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
296L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 343L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,
297L<Coro::Handle>, L<Coro::Socket>. 344L<Coro::Handle>, L<Coro::RWLock>, L<Coro::Socket>.
298 345
299=head1 AUTHOR 346=head1 AUTHOR
300 347
301 Marc Lehmann <pcg@goof.com> 348 Marc Lehmann <pcg@goof.com>
302 http://www.goof.com/pcg/marc/ 349 http://home.schmorp.de/
303 350
304=cut 351=cut
305 352

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