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Revision 1.30 by root, Sat Aug 11 19:59:19 2001 UTC vs.
Revision 1.74 by root, Mon Dec 26 18:48:11 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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35use strict;
36no warnings "uninitialized";
37
37use Coro::State; 38use Coro::State;
38 39
39use base Exporter; 40use base Exporter::;
40 41
41$VERSION = 0.45; 42our $idle; # idle coroutine
43our $main; # main coroutine
44our $current; # current coroutine
42 45
46our $VERSION = 1.7;
47
43@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
44@EXPORT_OK = qw($current); 49our %EXPORT_TAGS = (
50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51);
52our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
45 53
46{ 54{
47 my @async; 55 my @async;
48 my $init; 56 my $init;
49 57
50 # this way of handling attributes simply is NOT scalable ;() 58 # this way of handling attributes simply is NOT scalable ;()
51 sub import { 59 sub import {
60 no strict 'refs';
61
52 Coro->export_to_level(1, @_); 62 Coro->export_to_level(1, @_);
63
53 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 64 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
54 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { 65 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
55 my ($package, $ref) = (shift, shift); 66 my ($package, $ref) = (shift, shift);
56 my @attrs; 67 my @attrs;
57 for (@_) { 68 for (@_) {
72 }; 83 };
73 } 84 }
74 85
75} 86}
76 87
88=over 4
89
77=item $main 90=item $main
78 91
79This coroutine represents the main program. 92This coroutine represents the main program.
80 93
81=cut 94=cut
82 95
83our $main = new Coro; 96$main = new Coro;
84 97
85=item $current (or as function: current) 98=item $current (or as function: current)
86 99
87The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 100The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
88 101
91# maybe some other module used Coro::Specific before... 104# maybe some other module used Coro::Specific before...
92if ($current) { 105if ($current) {
93 $main->{specific} = $current->{specific}; 106 $main->{specific} = $current->{specific};
94} 107}
95 108
96our $current = $main; 109$current = $main;
97 110
98sub current() { $current } 111sub current() { $current }
99 112
100=item $idle 113=item $idle
101 114
103implementation prints "FATAL: deadlock detected" and exits. 116implementation prints "FATAL: deadlock detected" and exits.
104 117
105=cut 118=cut
106 119
107# should be done using priorities :( 120# should be done using priorities :(
108our $idle = new Coro sub { 121$idle = new Coro sub {
109 print STDERR "FATAL: deadlock detected\n"; 122 print STDERR "FATAL: deadlock detected\n";
110 exit(51); 123 exit(51);
111}; 124};
112 125
113# this coroutine is necessary because a coroutine 126# this coroutine is necessary because a coroutine
114# cannot destroy itself. 127# cannot destroy itself.
115my @destroy; 128my @destroy;
129my $manager;
116my $manager = new Coro sub { 130$manager = new Coro sub {
117 while() { 131 while () {
118 delete ((pop @destroy)->{_coro_state}) while @destroy; 132 # by overwriting the state object with the manager we destroy it
133 # while still being able to schedule this coroutine (in case it has
134 # been readied multiple times. this is harmless since the manager
135 # can be called as many times as neccessary and will always
136 # remove itself from the runqueue
137 while (@destroy) {
138 my $coro = pop @destroy;
139 $coro->{status} ||= [];
140 $_->ready for @{delete $coro->{join} || []};
141
142 # the next line destroys the _coro_state, but keeps the
143 # process itself intact (we basically make it a zombie
144 # process that always runs the manager thread, so it's possible
145 # to transfer() to this process).
146 $coro->{_coro_state} = $manager->{_coro_state};
147 }
119 &schedule; 148 &schedule;
120 } 149 }
121}; 150};
122 151
123# static methods. not really. 152# static methods. not really.
153
154=back
124 155
125=head2 STATIC METHODS 156=head2 STATIC METHODS
126 157
127Static methods are actually functions that operate on the current process only. 158Static methods are actually functions that operate on the current process only.
128 159
136 167
137 # create a new coroutine that just prints its arguments 168 # create a new coroutine that just prints its arguments
138 async { 169 async {
139 print "@_\n"; 170 print "@_\n";
140 } 1,2,3,4; 171 } 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.
144 172
145=cut 173=cut
146 174
147sub async(&@) { 175sub async(&@) {
148 my $pid = new Coro @_; 176 my $pid = new Coro @_;
165ready queue and calls C<schedule>, which has the effect of giving up the 193ready queue and calls C<schedule>, which has the effect of giving up the
166current "timeslice" to other coroutines of the same or higher priority. 194current "timeslice" to other coroutines of the same or higher priority.
167 195
168=cut 196=cut
169 197
170=item terminate 198=item terminate [arg...]
171 199
172Terminates the current process. 200Terminates the current process with the given status values (see L<cancel>).
173
174Future versions of this function will allow result arguments.
175 201
176=cut 202=cut
177 203
178sub terminate { 204sub terminate {
179 $current->cancel; 205 $current->cancel (@_);
180 &schedule;
181 die; # NORETURN
182} 206}
183 207
184=back 208=back
185 209
186# dynamic methods 210# dynamic methods
192=over 4 216=over 4
193 217
194=item new Coro \&sub [, @args...] 218=item new Coro \&sub [, @args...]
195 219
196Create a new process and return it. When the sub returns the process 220Create a new process and return it. When the sub returns the process
197automatically terminates. To start the process you must first put it into 221automatically terminates as if C<terminate> with the returned values were
222called. To make the process run you must first put it into the ready queue
198the ready queue by calling the ready method. 223by 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.
202 224
203=cut 225=cut
204 226
205sub _newcoro { 227sub _newcoro {
206 terminate &{+shift}; 228 terminate &{+shift};
213 }, $class; 235 }, $class;
214} 236}
215 237
216=item $process->ready 238=item $process->ready
217 239
218Put the current process into the ready queue. 240Put the given process into the ready queue.
219 241
220=cut 242=cut
221 243
222=item $process->cancel 244=item $process->cancel (arg...)
223 245
224Like C<terminate>, but terminates the specified process instead. 246Temrinates the given process and makes it return the given arguments as
247status (default: the empty list).
225 248
226=cut 249=cut
227 250
228sub cancel { 251sub cancel {
252 my $self = shift;
253 $self->{status} = [@_];
229 push @destroy, $_[0]; 254 push @destroy, $self;
230 $manager->ready; 255 $manager->ready;
256 &schedule if $current == $self;
257}
258
259=item $process->join
260
261Wait until the coroutine terminates and return any values given to the
262C<terminate> or C<cancel> functions. C<join> can be called multiple times
263from multiple processes.
264
265=cut
266
267sub join {
268 my $self = shift;
269 unless ($self->{status}) {
270 push @{$self->{join}}, $current;
271 &schedule;
272 }
273 wantarray ? @{$self->{status}} : $self->{status}[0];
274}
275
276=item $oldprio = $process->prio($newprio)
277
278Sets (or gets, if the argument is missing) the priority of the
279process. Higher priority processes get run before lower priority
280processes. Priorities are small signed integers (currently -4 .. +3),
281that you can refer to using PRIO_xxx constants (use the import tag :prio
282to get then):
283
284 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
285 3 > 1 > 0 > -1 > -3 > -4
286
287 # set priority to HIGH
288 current->prio(PRIO_HIGH);
289
290The idle coroutine ($Coro::idle) always has a lower priority than any
291existing coroutine.
292
293Changing the priority of the current process will take effect immediately,
294but changing the priority of processes in the ready queue (but not
295running) will only take effect after the next schedule (of that
296process). This is a bug that will be fixed in some future version.
297
298=cut
299
300sub prio {
301 my $old = $_[0]{prio};
302 $_[0]{prio} = $_[1] if @_ > 1;
303 $old;
304}
305
306=item $newprio = $process->nice($change)
307
308Similar to C<prio>, but subtract the given value from the priority (i.e.
309higher values mean lower priority, just as in unix).
310
311=cut
312
313sub nice {
314 $_[0]{prio} -= $_[1];
315}
316
317=item $olddesc = $process->desc($newdesc)
318
319Sets (or gets in case the argument is missing) the description for this
320process. This is just a free-form string you can associate with a process.
321
322=cut
323
324sub desc {
325 my $old = $_[0]{desc};
326 $_[0]{desc} = $_[1] if @_ > 1;
327 $old;
231} 328}
232 329
233=back 330=back
234 331
235=cut 332=cut
236 333
2371; 3341;
238 335
239=head1 BUGS/LIMITATIONS 336=head1 BUGS/LIMITATIONS
240 337
241 - could be faster, especially when the core would introduce special 338 - you must make very sure that no coro is still active on global
242 support for coroutines (like it does for threads). 339 destruction. very bad things might happen otherwise (usually segfaults).
243 - there is still a memleak on coroutine termination that I could not 340
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 341 - 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 342 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). 343 to allow per-thread schedulers, but Coro::State does not yet allow
344 this).
252 345
253=head1 SEE ALSO 346=head1 SEE ALSO
254 347
255L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 348Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
256L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 349
257L<Coro::Handle>, L<Coro::Socket>. 350Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
351
352Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
353
354Embedding: L<Coro:MakeMaker>
258 355
259=head1 AUTHOR 356=head1 AUTHOR
260 357
261 Marc Lehmann <pcg@goof.com> 358 Marc Lehmann <schmorp@schmorp.de>
262 http://www.goof.com/pcg/marc/ 359 http://home.schmorp.de/
263 360
264=cut 361=cut
265 362

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