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Revision 1.32 by root, Sun Sep 2 01:03:53 2001 UTC vs.
Revision 1.80 by root, Mon Nov 6 19:56:26 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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35use strict;
36no warnings "uninitialized";
37
37use Coro::State; 38use Coro::State;
38 39
39use base Exporter; 40use base Exporter::;
40 41
41$VERSION = 0.49; 42our $idle; # idle coroutine
43our $main; # main coroutine
44our $current; # current coroutine
42 45
46our $VERSION = '2.5';
47
43@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
44%EXPORT_TAGS = ( 49our %EXPORT_TAGS = (
45 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
46); 51);
47@EXPORT_OK = @{$EXPORT_TAGS{prio}}; 52our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
48 53
49{ 54{
50 my @async; 55 my @async;
51 my $init; 56 my $init;
52 57
53 # this way of handling attributes simply is NOT scalable ;() 58 # this way of handling attributes simply is NOT scalable ;()
54 sub import { 59 sub import {
60 no strict 'refs';
61
55 Coro->export_to_level(1, @_); 62 Coro->export_to_level(1, @_);
63
56 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 64 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
57 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { 65 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
58 my ($package, $ref) = (shift, shift); 66 my ($package, $ref) = (shift, shift);
59 my @attrs; 67 my @attrs;
60 for (@_) { 68 for (@_) {
75 }; 83 };
76 } 84 }
77 85
78} 86}
79 87
88=over 4
89
80=item $main 90=item $main
81 91
82This coroutine represents the main program. 92This coroutine represents the main program.
83 93
84=cut 94=cut
85 95
86our $main = new Coro; 96$main = new Coro;
87 97
88=item $current (or as function: current) 98=item $current (or as function: current)
89 99
90The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 100The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
91 101
94# maybe some other module used Coro::Specific before... 104# maybe some other module used Coro::Specific before...
95if ($current) { 105if ($current) {
96 $main->{specific} = $current->{specific}; 106 $main->{specific} = $current->{specific};
97} 107}
98 108
99our $current = $main; 109$current = $main;
100 110
101sub current() { $current } 111sub current() { $current }
102 112
103=item $idle 113=item $idle
104 114
106implementation prints "FATAL: deadlock detected" and exits. 116implementation prints "FATAL: deadlock detected" and exits.
107 117
108=cut 118=cut
109 119
110# should be done using priorities :( 120# should be done using priorities :(
111our $idle = new Coro sub { 121$idle = new Coro sub {
112 print STDERR "FATAL: deadlock detected\n"; 122 print STDERR "FATAL: deadlock detected\n";
113 exit(51); 123 exit(51);
114}; 124};
115 125
116# this coroutine is necessary because a coroutine 126# this coroutine is necessary because a coroutine
117# cannot destroy itself. 127# cannot destroy itself.
118my @destroy; 128my @destroy;
129my $manager;
119my $manager = new Coro sub { 130$manager = new Coro sub {
120 while() { 131 while () {
121 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 }
122 &schedule; 148 &schedule;
123 } 149 }
124}; 150};
125 151
126# static methods. not really. 152# static methods. not really.
127 153
154=back
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
132=over 4 160=over 4
134=item async { ... } [@args...] 162=item async { ... } [@args...]
135 163
136Create a new asynchronous process and return it's process object 164Create a new asynchronous process and return it's process object
137(usually unused). When the sub returns the new process is automatically 165(usually unused). When the sub returns the new process is automatically
138terminated. 166terminated.
167
168When the coroutine dies, the program will exit, just as in the main
169program.
139 170
140 # create a new coroutine that just prints its arguments 171 # create a new coroutine that just prints its arguments
141 async { 172 async {
142 print "@_\n"; 173 print "@_\n";
143 } 1,2,3,4; 174 } 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.
147 175
148=cut 176=cut
149 177
150sub async(&@) { 178sub async(&@) {
151 my $pid = new Coro @_; 179 my $pid = new Coro @_;
168ready queue and calls C<schedule>, which has the effect of giving up the 196ready queue and calls C<schedule>, which has the effect of giving up the
169current "timeslice" to other coroutines of the same or higher priority. 197current "timeslice" to other coroutines of the same or higher priority.
170 198
171=cut 199=cut
172 200
173=item terminate 201=item terminate [arg...]
174 202
175Terminates the current process. 203Terminates the current process with the given status values (see L<cancel>).
176
177Future versions of this function will allow result arguments.
178 204
179=cut 205=cut
180 206
181sub terminate { 207sub terminate {
182 $current->cancel; 208 $current->cancel (@_);
183 &schedule;
184 die; # NORETURN
185} 209}
186 210
187=back 211=back
188 212
189# dynamic methods 213# dynamic methods
195=over 4 219=over 4
196 220
197=item new Coro \&sub [, @args...] 221=item new Coro \&sub [, @args...]
198 222
199Create a new process and return it. When the sub returns the process 223Create a new process and return it. When the sub returns the process
200automatically terminates. To start the process you must first put it into 224automatically terminates as if C<terminate> with the returned values were
225called. To make the process run you must first put it into the ready queue
201the ready queue by calling the ready method. 226by calling the ready method.
202
203The coderef you submit MUST NOT be a closure that refers to variables
204in an outer scope. This does NOT work. Pass arguments into it instead.
205 227
206=cut 228=cut
207 229
208sub _newcoro { 230sub _newcoro {
209 terminate &{+shift}; 231 terminate &{+shift};
216 }, $class; 238 }, $class;
217} 239}
218 240
219=item $process->ready 241=item $process->ready
220 242
221Put the current process into the ready queue. 243Put the given process into the ready queue.
222 244
223=cut 245=cut
224 246
225=item $process->cancel 247=item $process->cancel (arg...)
226 248
227Like C<terminate>, but terminates the specified process instead. 249Terminates the given process and makes it return the given arguments as
250status (default: the empty list).
228 251
229=cut 252=cut
230 253
231sub cancel { 254sub cancel {
255 my $self = shift;
256 $self->{status} = [@_];
232 push @destroy, $_[0]; 257 push @destroy, $self;
233 $manager->ready; 258 $manager->ready;
259 &schedule if $current == $self;
260}
261
262=item $process->join
263
264Wait until the coroutine terminates and return any values given to the
265C<terminate> or C<cancel> functions. C<join> can be called multiple times
266from multiple processes.
267
268=cut
269
270sub join {
271 my $self = shift;
272 unless ($self->{status}) {
273 push @{$self->{join}}, $current;
274 &schedule;
275 }
276 wantarray ? @{$self->{status}} : $self->{status}[0];
234} 277}
235 278
236=item $oldprio = $process->prio($newprio) 279=item $oldprio = $process->prio($newprio)
237 280
238Sets the priority of the process. Higher priority processes get run before 281Sets (or gets, if the argument is missing) the priority of the
282process. Higher priority processes get run before lower priority
239lower priority processes. Priorities are smalled signed integer (currently 283processes. Priorities are small signed integers (currently -4 .. +3),
240-4 .. +3), that you can refer to using PRIO_xxx constants (use the import 284that you can refer to using PRIO_xxx constants (use the import tag :prio
241tag :prio to get then): 285to get then):
242 286
243 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 287 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
244 3 > 1 > 0 > -1 > -3 > -4 288 3 > 1 > 0 > -1 > -3 > -4
245 289
246 # set priority to HIGH 290 # set priority to HIGH
271 315
272sub nice { 316sub nice {
273 $_[0]{prio} -= $_[1]; 317 $_[0]{prio} -= $_[1];
274} 318}
275 319
320=item $olddesc = $process->desc($newdesc)
321
322Sets (or gets in case the argument is missing) the description for this
323process. This is just a free-form string you can associate with a process.
324
325=cut
326
327sub desc {
328 my $old = $_[0]{desc};
329 $_[0]{desc} = $_[1] if @_ > 1;
330 $old;
331}
332
276=back 333=back
277 334
278=cut 335=cut
279 336
2801; 3371;
281 338
282=head1 BUGS/LIMITATIONS 339=head1 BUGS/LIMITATIONS
283 340
284 - could be faster, especially when the core would introduce special 341 - you must make very sure that no coro is still active on global
285 support for coroutines (like it does for threads). 342 destruction. very bad things might happen otherwise (usually segfaults).
286 - there is still a memleak on coroutine termination that I could not 343
287 identify. Could be as small as a single SV.
288 - this module is not well-tested.
289 - if variables or arguments "disappear" (become undef) or become
290 corrupted please contact the author so he cen iron out the
291 remaining bugs.
292 - this module is not thread-safe. You must only ever use this module from 344 - this module is not thread-safe. You should only ever use this module
293 the same thread (this requirement might be loosened in the future to 345 from the same thread (this requirement might be losened in the future
294 allow per-thread schedulers, but Coro::State does not yet allow this). 346 to allow per-thread schedulers, but Coro::State does not yet allow
347 this).
295 348
296=head1 SEE ALSO 349=head1 SEE ALSO
297 350
298L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 351Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
299L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 352
300L<Coro::Handle>, L<Coro::Socket>. 353Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
354
355Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
356
357Embedding: L<Coro:MakeMaker>
301 358
302=head1 AUTHOR 359=head1 AUTHOR
303 360
304 Marc Lehmann <pcg@goof.com> 361 Marc Lehmann <schmorp@schmorp.de>
305 http://www.goof.com/pcg/marc/ 362 http://home.schmorp.de/
306 363
307=cut 364=cut
308 365

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