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Revision 1.38 by root, Wed Oct 3 01:09:56 2001 UTC vs.
Revision 1.61 by pcg, Fri May 14 13:25:08 2004 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 = 0.51; 43$VERSION = 0.97;
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;
121my $manager; 123my $manager;
122$manager = new Coro sub { 124$manager = new Coro sub {
123 while() { 125 while () {
124 # by overwriting the state object with the manager we destroy it 126 # by overwriting the state object with the manager we destroy it
125 # while still being able to schedule this coroutine (in case it has 127 # while still being able to schedule this coroutine (in case it has
126 # been readied multiple times. this is harmless since the manager 128 # been readied multiple times. this is harmless since the manager
127 # can be called as many times as neccessary and will always 129 # can be called as many times as neccessary and will always
128 # remove itself from the runqueue 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).
129 (pop @destroy)->{_coro_state} = $manager->{_coro_state} while @destroy; 140 $coro->{_coro_state} = $manager->{_coro_state};
141 }
130 &schedule; 142 &schedule;
131 } 143 }
132}; 144};
133 145
134# static methods. not really. 146# static methods. not really.
147
148=back
135 149
136=head2 STATIC METHODS 150=head2 STATIC METHODS
137 151
138Static methods are actually functions that operate on the current process only. 152Static methods are actually functions that operate on the current process only.
139 153
147 161
148 # create a new coroutine that just prints its arguments 162 # create a new coroutine that just prints its arguments
149 async { 163 async {
150 print "@_\n"; 164 print "@_\n";
151 } 1,2,3,4; 165 } 1,2,3,4;
152
153The coderef you submit MUST NOT be a closure that refers to variables
154in an outer scope. This does NOT work. Pass arguments into it instead.
155 166
156=cut 167=cut
157 168
158sub async(&@) { 169sub async(&@) {
159 my $pid = new Coro @_; 170 my $pid = new Coro @_;
176ready 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
177current "timeslice" to other coroutines of the same or higher priority. 188current "timeslice" to other coroutines of the same or higher priority.
178 189
179=cut 190=cut
180 191
181=item terminate 192=item terminate [arg...]
182 193
183Terminates the current process. 194Terminates the current process with the given status values (see L<cancel>).
184
185Future versions of this function will allow result arguments.
186 195
187=cut 196=cut
188 197
189sub terminate { 198sub terminate {
190 $current->cancel; 199 $current->cancel (@_);
191 &schedule;
192 die; # NORETURN
193} 200}
194 201
195=back 202=back
196 203
197# dynamic methods 204# dynamic methods
203=over 4 210=over 4
204 211
205=item new Coro \&sub [, @args...] 212=item new Coro \&sub [, @args...]
206 213
207Create 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
208automatically 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
209the ready queue by calling the ready method. 217by 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.
213 218
214=cut 219=cut
215 220
216sub _newcoro { 221sub _newcoro {
217 terminate &{+shift}; 222 terminate &{+shift};
224 }, $class; 229 }, $class;
225} 230}
226 231
227=item $process->ready 232=item $process->ready
228 233
229Put the current process into the ready queue. 234Put the given process into the ready queue.
230 235
231=cut 236=cut
232 237
233=item $process->cancel 238=item $process->cancel (arg...)
234 239
235Like 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).
236 242
237=cut 243=cut
238 244
239sub cancel { 245sub cancel {
246 my $self = shift;
247 $self->{status} = [@_];
240 push @destroy, $_[0]; 248 push @destroy, $self;
241 $manager->ready; 249 $manager->ready;
242 &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];
243} 268}
244 269
245=item $oldprio = $process->prio($newprio) 270=item $oldprio = $process->prio($newprio)
246 271
247Sets 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
248lower priority processes. Priorities are smalled signed integer (currently 274processes. Priorities are small signed integers (currently -4 .. +3),
249-4 .. +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
250tag :prio to get then): 276to get then):
251 277
252 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
253 3 > 1 > 0 > -1 > -3 > -4 279 3 > 1 > 0 > -1 > -3 > -4
254 280
255 # set priority to HIGH 281 # set priority to HIGH
280 306
281sub nice { 307sub nice {
282 $_[0]{prio} -= $_[1]; 308 $_[0]{prio} -= $_[1];
283} 309}
284 310
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
285=back 324=back
286 325
287=cut 326=cut
288 327
2891; 3281;
290 329
291=head1 BUGS/LIMITATIONS 330=head1 BUGS/LIMITATIONS
292 331
293 - 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
294 very bad things might happen otherwise (usually segfaults). 333 destruction. very bad things might happen otherwise (usually segfaults).
334
295 - 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
296 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
297 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).
298 339
299=head1 SEE ALSO 340=head1 SEE ALSO
300 341
301L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 342L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
302L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 343L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,
303L<Coro::Handle>, L<Coro::Socket>. 344L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>.
304 345
305=head1 AUTHOR 346=head1 AUTHOR
306 347
307 Marc Lehmann <pcg@goof.com> 348 Marc Lehmann <pcg@goof.com>
308 http://www.goof.com/pcg/marc/ 349 http://www.goof.com/pcg/marc/

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