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Revision 1.28 by root, Fri Aug 10 21:03:40 2001 UTC vs.
Revision 1.78 by root, Wed Nov 1 01:21:21 2006 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
42our $idle; # idle coroutine
43our $main; # main coroutine
44our $current; # current coroutine
45
41$VERSION = 0.13; 46our $VERSION = '2.1';
42 47
43@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
44@EXPORT_OK = qw($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# we really need priorities...
124my @ready; # the ready queue. hehe, rather broken ;)
125
126# static methods. not really. 152# static methods. not really.
153
154=back
127 155
128=head2 STATIC METHODS 156=head2 STATIC METHODS
129 157
130Static methods are actually functions that operate on the current process only. 158Static methods are actually functions that operate on the current process only.
131 159
139 167
140 # create a new coroutine that just prints its arguments 168 # create a new coroutine that just prints its arguments
141 async { 169 async {
142 print "@_\n"; 170 print "@_\n";
143 } 1,2,3,4; 171 } 1,2,3,4;
144
145The coderef you submit MUST NOT be a closure that refers to variables
146in an outer scope. This does NOT work. Pass arguments into it instead.
147 172
148=cut 173=cut
149 174
150sub async(&@) { 175sub async(&@) {
151 my $pid = new Coro @_; 176 my $pid = new Coro @_;
160into the ready queue, so calling this function usually means you will 185into the ready queue, so calling this function usually means you will
161never be called again. 186never be called again.
162 187
163=cut 188=cut
164 189
165my $prev;
166
167sub schedule {
168 # should be done using priorities :(
169 ($prev, $current) = ($current, shift @ready || $idle);
170 Coro::State::transfer($prev, $current);
171}
172
173=item cede 190=item cede
174 191
175"Cede" to other processes. This function puts the current process into the 192"Cede" to other processes. This function puts the current process into the
176ready 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
177current "timeslice" to other coroutines of the same or higher priority. 194current "timeslice" to other coroutines of the same or higher priority.
178 195
179=cut 196=cut
180 197
181sub cede {
182 $current->ready;
183 &schedule;
184}
185
186=item terminate 198=item terminate [arg...]
187 199
188Terminates the current process. 200Terminates the current process with the given status values (see L<cancel>).
189
190Future versions of this function will allow result arguments.
191 201
192=cut 202=cut
193 203
194sub terminate { 204sub terminate {
195 $current->cancel; 205 $current->cancel (@_);
196 &schedule;
197 die; # NORETURN
198} 206}
199 207
200=back 208=back
201 209
202# dynamic methods 210# dynamic methods
208=over 4 216=over 4
209 217
210=item new Coro \&sub [, @args...] 218=item new Coro \&sub [, @args...]
211 219
212Create 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
213automatically 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
214the ready queue by calling the ready method. 223by calling the ready method.
215
216The coderef you submit MUST NOT be a closure that refers to variables
217in an outer scope. This does NOT work. Pass arguments into it instead.
218 224
219=cut 225=cut
220 226
221sub _newcoro { 227sub _newcoro {
222 terminate &{+shift}; 228 terminate &{+shift};
229 }, $class; 235 }, $class;
230} 236}
231 237
232=item $process->ready 238=item $process->ready
233 239
234Put the current process into the ready queue. 240Put the given process into the ready queue.
235 241
236=cut 242=cut
237 243
238sub ready {
239 push @ready, $_[0];
240}
241
242=item $process->cancel 244=item $process->cancel (arg...)
243 245
244Like 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).
245 248
246=cut 249=cut
247 250
248sub cancel { 251sub cancel {
252 my $self = shift;
253 $self->{status} = [@_];
249 push @destroy, $_[0]; 254 push @destroy, $self;
250 $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;
251} 328}
252 329
253=back 330=back
254 331
255=cut 332=cut
256 333
2571; 3341;
258 335
259=head1 BUGS/LIMITATIONS 336=head1 BUGS/LIMITATIONS
260 337
261 - could be faster, especially when the core would introduce special 338 - you must make very sure that no coro is still active on global
262 support for coroutines (like it does for threads). 339 destruction. very bad things might happen otherwise (usually segfaults).
263 - there is still a memleak on coroutine termination that I could not 340
264 identify. Could be as small as a single SV.
265 - this module is not well-tested.
266 - if variables or arguments "disappear" (become undef) or become
267 corrupted please contact the author so he cen iron out the
268 remaining bugs.
269 - 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
270 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
271 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).
272 345
273=head1 SEE ALSO 346=head1 SEE ALSO
274 347
275L<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>.
276L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 349
277L<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>
278 355
279=head1 AUTHOR 356=head1 AUTHOR
280 357
281 Marc Lehmann <pcg@goof.com> 358 Marc Lehmann <schmorp@schmorp.de>
282 http://www.goof.com/pcg/marc/ 359 http://home.schmorp.de/
283 360
284=cut 361=cut
285 362

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