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Revision 1.30 by root, Sat Aug 11 19:59:19 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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") }
36
37use Coro::State; 37use Coro::State;
38 38
39use vars qw($idle $main $current);
40
39use base Exporter; 41use base Exporter;
40 42
41$VERSION = 0.45; 43$VERSION = 0.97;
42 44
43@EXPORT = qw(async cede schedule terminate current); 45@EXPORT = qw(async cede schedule terminate current);
44@EXPORT_OK = qw($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}};
45 50
46{ 51{
47 my @async; 52 my @async;
48 my $init; 53 my $init;
49 54
72 }; 77 };
73 } 78 }
74 79
75} 80}
76 81
82=over 4
83
77=item $main 84=item $main
78 85
79This coroutine represents the main program. 86This coroutine represents the main program.
80 87
81=cut 88=cut
82 89
83our $main = new Coro; 90$main = new Coro;
84 91
85=item $current (or as function: current) 92=item $current (or as function: current)
86 93
87The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 94The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
88 95
91# maybe some other module used Coro::Specific before... 98# maybe some other module used Coro::Specific before...
92if ($current) { 99if ($current) {
93 $main->{specific} = $current->{specific}; 100 $main->{specific} = $current->{specific};
94} 101}
95 102
96our $current = $main; 103$current = $main;
97 104
98sub current() { $current } 105sub current() { $current }
99 106
100=item $idle 107=item $idle
101 108
103implementation prints "FATAL: deadlock detected" and exits. 110implementation prints "FATAL: deadlock detected" and exits.
104 111
105=cut 112=cut
106 113
107# should be done using priorities :( 114# should be done using priorities :(
108our $idle = new Coro sub { 115$idle = new Coro sub {
109 print STDERR "FATAL: deadlock detected\n"; 116 print STDERR "FATAL: deadlock detected\n";
110 exit(51); 117 exit(51);
111}; 118};
112 119
113# this coroutine is necessary because a coroutine 120# this coroutine is necessary because a coroutine
114# cannot destroy itself. 121# cannot destroy itself.
115my @destroy; 122my @destroy;
123my $manager;
116my $manager = new Coro sub { 124$manager = new Coro sub {
117 while() { 125 while () {
118 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 }
119 &schedule; 142 &schedule;
120 } 143 }
121}; 144};
122 145
123# static methods. not really. 146# static methods. not really.
147
148=back
124 149
125=head2 STATIC METHODS 150=head2 STATIC METHODS
126 151
127Static methods are actually functions that operate on the current process only. 152Static methods are actually functions that operate on the current process only.
128 153
136 161
137 # create a new coroutine that just prints its arguments 162 # create a new coroutine that just prints its arguments
138 async { 163 async {
139 print "@_\n"; 164 print "@_\n";
140 } 1,2,3,4; 165 } 1,2,3,4;
141
142The coderef you submit MUST NOT be a closure that refers to variables
143in an outer scope. This does NOT work. Pass arguments into it instead.
144 166
145=cut 167=cut
146 168
147sub async(&@) { 169sub async(&@) {
148 my $pid = new Coro @_; 170 my $pid = new Coro @_;
165ready 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
166current "timeslice" to other coroutines of the same or higher priority. 188current "timeslice" to other coroutines of the same or higher priority.
167 189
168=cut 190=cut
169 191
170=item terminate 192=item terminate [arg...]
171 193
172Terminates the current process. 194Terminates the current process with the given status values (see L<cancel>).
173
174Future versions of this function will allow result arguments.
175 195
176=cut 196=cut
177 197
178sub terminate { 198sub terminate {
179 $current->cancel; 199 $current->cancel (@_);
180 &schedule;
181 die; # NORETURN
182} 200}
183 201
184=back 202=back
185 203
186# dynamic methods 204# dynamic methods
192=over 4 210=over 4
193 211
194=item new Coro \&sub [, @args...] 212=item new Coro \&sub [, @args...]
195 213
196Create 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
197automatically 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
198the ready queue by calling the ready method. 217by calling the ready method.
199
200The coderef you submit MUST NOT be a closure that refers to variables
201in an outer scope. This does NOT work. Pass arguments into it instead.
202 218
203=cut 219=cut
204 220
205sub _newcoro { 221sub _newcoro {
206 terminate &{+shift}; 222 terminate &{+shift};
213 }, $class; 229 }, $class;
214} 230}
215 231
216=item $process->ready 232=item $process->ready
217 233
218Put the current process into the ready queue. 234Put the given process into the ready queue.
219 235
220=cut 236=cut
221 237
222=item $process->cancel 238=item $process->cancel (arg...)
223 239
224Like 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).
225 242
226=cut 243=cut
227 244
228sub cancel { 245sub cancel {
246 my $self = shift;
247 $self->{status} = [@_];
229 push @destroy, $_[0]; 248 push @destroy, $self;
230 $manager->ready; 249 $manager->ready;
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];
268}
269
270=item $oldprio = $process->prio($newprio)
271
272Sets (or gets, if the argument is missing) the priority of the
273process. Higher priority processes get run before lower priority
274processes. Priorities are small signed integers (currently -4 .. +3),
275that you can refer to using PRIO_xxx constants (use the import tag :prio
276to get then):
277
278 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
279 3 > 1 > 0 > -1 > -3 > -4
280
281 # set priority to HIGH
282 current->prio(PRIO_HIGH);
283
284The idle coroutine ($Coro::idle) always has a lower priority than any
285existing coroutine.
286
287Changing the priority of the current process will take effect immediately,
288but changing the priority of processes in the ready queue (but not
289running) will only take effect after the next schedule (of that
290process). This is a bug that will be fixed in some future version.
291
292=cut
293
294sub prio {
295 my $old = $_[0]{prio};
296 $_[0]{prio} = $_[1] if @_ > 1;
297 $old;
298}
299
300=item $newprio = $process->nice($change)
301
302Similar to C<prio>, but subtract the given value from the priority (i.e.
303higher values mean lower priority, just as in unix).
304
305=cut
306
307sub nice {
308 $_[0]{prio} -= $_[1];
309}
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;
231} 322}
232 323
233=back 324=back
234 325
235=cut 326=cut
236 327
2371; 3281;
238 329
239=head1 BUGS/LIMITATIONS 330=head1 BUGS/LIMITATIONS
240 331
241 - could be faster, especially when the core would introduce special 332 - you must make very sure that no coro is still active on global
242 support for coroutines (like it does for threads). 333 destruction. very bad things might happen otherwise (usually segfaults).
243 - there is still a memleak on coroutine termination that I could not 334
244 identify. Could be as small as a single SV.
245 - this module is not well-tested.
246 - if variables or arguments "disappear" (become undef) or become
247 corrupted please contact the author so he cen iron out the
248 remaining bugs.
249 - 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
250 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
251 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).
252 339
253=head1 SEE ALSO 340=head1 SEE ALSO
254 341
255L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 342L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
256L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 343L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,
257L<Coro::Handle>, L<Coro::Socket>. 344L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>.
258 345
259=head1 AUTHOR 346=head1 AUTHOR
260 347
261 Marc Lehmann <pcg@goof.com> 348 Marc Lehmann <pcg@goof.com>
262 http://www.goof.com/pcg/marc/ 349 http://www.goof.com/pcg/marc/

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