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Revision 1.40 by root, Sun Oct 28 17:00:05 2001 UTC vs.
Revision 1.88 by root, Sun Nov 26 02:54:55 2006 UTC

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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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35use strict;
37no warnings qw(uninitialized); 36no warnings "uninitialized";
38 37
39use Coro::State; 38use Coro::State;
40 39
41use base Exporter; 40use base qw(Coro::State Exporter);
42 41
43$VERSION = 0.51; 42our $idle; # idle handler
43our $main; # main coroutine
44our $current; # current coroutine
44 45
46our $VERSION = '3.0';
47
45@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
46%EXPORT_TAGS = ( 49our %EXPORT_TAGS = (
47 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48); 51);
49@EXPORT_OK = @{$EXPORT_TAGS{prio}}; 52our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
50 53
51{ 54{
52 my @async; 55 my @async;
53 my $init; 56 my $init;
54 57
55 # this way of handling attributes simply is NOT scalable ;() 58 # this way of handling attributes simply is NOT scalable ;()
56 sub import { 59 sub import {
60 no strict 'refs';
61
57 Coro->export_to_level(1, @_); 62 Coro->export_to_level(1, @_);
63
58 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 64 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
59 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { 65 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
60 my ($package, $ref) = (shift, shift); 66 my ($package, $ref) = (shift, shift);
61 my @attrs; 67 my @attrs;
62 for (@_) { 68 for (@_) {
… …
77 }; 83 };
78 } 84 }
79 85
80} 86}
81 87
88=over 4
89
82=item $main 90=item $main
83 91
84This coroutine represents the main program. 92This coroutine represents the main program.
85 93
86=cut 94=cut
87 95
88our $main = new Coro; 96$main = new Coro;
89 97
90=item $current (or as function: current) 98=item $current (or as function: current)
91 99
92The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 100The current coroutine (the last coroutine switched to). The initial value
101is C<$main> (of course).
102
103This variable is B<strictly> I<read-only>. It is provided for performance
104reasons. If performance is not essentiel you are encouraged to use the
105C<Coro::current> function instead.
93 106
94=cut 107=cut
95 108
96# maybe some other module used Coro::Specific before... 109# maybe some other module used Coro::Specific before...
97if ($current) { 110if ($current) {
98 $main->{specific} = $current->{specific}; 111 $main->{specific} = $current->{specific};
99} 112}
100 113
101our $current = $main; 114$current = $main;
102 115
103sub current() { $current } 116sub current() { $current }
104 117
105=item $idle 118=item $idle
106 119
107The coroutine to switch to when no other coroutine is running. The default 120A callback that is called whenever the scheduler finds no ready coroutines
108implementation prints "FATAL: deadlock detected" and exits. 121to run. The default implementation prints "FATAL: deadlock detected" and
122exits.
109 123
110=cut 124This hook is overwritten by modules such as C<Coro::Timer> and
125C<Coro::Event> to wait on an external event that hopefully wakes up some
126coroutine.
111 127
112# should be done using priorities :( 128=cut
113our $idle = new Coro sub { 129
130$idle = sub {
114 print STDERR "FATAL: deadlock detected\n"; 131 print STDERR "FATAL: deadlock detected\n";
115 exit(51); 132 exit (51);
116}; 133};
117 134
118# this coroutine is necessary because a coroutine 135# this coroutine is necessary because a coroutine
119# cannot destroy itself. 136# cannot destroy itself.
120my @destroy; 137my @destroy;
121my $manager;
122$manager = new Coro sub { 138my $manager; $manager = new Coro sub {
123 while() { 139 while () {
124 # by overwriting the state object with the manager we destroy it 140 # by overwriting the state object with the manager we destroy it
125 # while still being able to schedule this coroutine (in case it has 141 # while still being able to schedule this coroutine (in case it has
126 # been readied multiple times. this is harmless since the manager 142 # been readied multiple times. this is harmless since the manager
127 # can be called as many times as neccessary and will always 143 # can be called as many times as neccessary and will always
128 # remove itself from the runqueue 144 # remove itself from the runqueue
129 while (@destroy) { 145 while (@destroy) {
130 my $coro = pop @destroy; 146 my $coro = pop @destroy;
131 $coro->{status} ||= []; 147 $coro->{status} ||= [];
132 $_->ready for @{delete $coro->{join} || []}; 148 $_->ready for @{delete $coro->{join} || []};
133 $coro->{_coro_state} = $manager->{_coro_state}; 149
150 # the next line destroys the coro state, but keeps the
151 # process itself intact (we basically make it a zombie
152 # process that always runs the manager thread, so it's possible
153 # to transfer() to this process).
154 $coro->_clone_state_from ($manager);
134 } 155 }
135 &schedule; 156 &schedule;
136 } 157 }
137}; 158};
138 159
139# static methods. not really. 160# static methods. not really.
140 161
162=back
163
141=head2 STATIC METHODS 164=head2 STATIC METHODS
142 165
143Static methods are actually functions that operate on the current process only. 166Static methods are actually functions that operate on the current process only.
144 167
145=over 4 168=over 4
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147=item async { ... } [@args...] 170=item async { ... } [@args...]
148 171
149Create a new asynchronous process and return it's process object 172Create a new asynchronous process and return it's process object
150(usually unused). When the sub returns the new process is automatically 173(usually unused). When the sub returns the new process is automatically
151terminated. 174terminated.
175
176When the coroutine dies, the program will exit, just as in the main
177program.
152 178
153 # create a new coroutine that just prints its arguments 179 # create a new coroutine that just prints its arguments
154 async { 180 async {
155 print "@_\n"; 181 print "@_\n";
156 } 1,2,3,4; 182 } 1,2,3,4;
157 183
158The coderef you submit MUST NOT be a closure that refers to variables
159in an outer scope. This does NOT work. Pass arguments into it instead.
160
161=cut 184=cut
162 185
163sub async(&@) { 186sub async(&@) {
164 my $pid = new Coro @_; 187 my $pid = new Coro @_;
165 $manager->ready; # this ensures that the stack is cloned from the manager
166 $pid->ready; 188 $pid->ready;
167 $pid; 189 $pid
168} 190}
169 191
170=item schedule 192=item schedule
171 193
172Calls the scheduler. Please note that the current process will not be put 194Calls the scheduler. Please note that the current process will not be put
… …
183 205
184=cut 206=cut
185 207
186=item terminate [arg...] 208=item terminate [arg...]
187 209
188Terminates the current process. 210Terminates the current process with the given status values (see L<cancel>).
189
190Future versions of this function will allow result arguments.
191 211
192=cut 212=cut
193 213
194sub terminate { 214sub terminate {
195 $current->{status} = [@_];
196 $current->cancel; 215 $current->cancel (@_);
197 &schedule;
198 die; # NORETURN
199} 216}
200 217
201=back 218=back
202 219
203# dynamic methods 220# dynamic methods
… …
210 227
211=item new Coro \&sub [, @args...] 228=item new Coro \&sub [, @args...]
212 229
213Create a new process and return it. When the sub returns the process 230Create a new process and return it. When the sub returns the process
214automatically terminates as if C<terminate> with the returned values were 231automatically terminates as if C<terminate> with the returned values were
215called. To start the process you must first put it into the ready queue by 232called. To make the process run you must first put it into the ready queue
216calling the ready method. 233by calling the ready method.
217 234
218The coderef you submit MUST NOT be a closure that refers to variables
219in an outer scope. This does NOT work. Pass arguments into it instead.
220
221=cut 235=cut
222 236
223sub _newcoro { 237sub _new_coro {
224 terminate &{+shift}; 238 terminate &{+shift};
225} 239}
226 240
227sub new { 241sub new {
228 my $class = shift; 242 my $class = shift;
229 bless { 243
230 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 244 $class->SUPER::new (\&_new_coro, @_)
231 }, $class;
232} 245}
233 246
234=item $process->ready 247=item $process->ready
235 248
236Put the given process into the ready queue. 249Put the given process into the ready queue.
237 250
238=cut 251=cut
239 252
240=item $process->cancel 253=item $process->cancel (arg...)
241 254
242Like C<terminate>, but terminates the specified process instead. 255Terminates the given process and makes it return the given arguments as
256status (default: the empty list).
243 257
244=cut 258=cut
245 259
246sub cancel { 260sub cancel {
261 my $self = shift;
262 $self->{status} = [@_];
247 push @destroy, $_[0]; 263 push @destroy, $self;
248 $manager->ready; 264 $manager->ready;
249 &schedule if $current == $_[0]; 265 &schedule if $current == $self;
250} 266}
251 267
252=item $process->join 268=item $process->join
253 269
254Wait until the coroutine terminates and return any values given to the 270Wait until the coroutine terminates and return any values given to the
255C<terminate> function. C<join> can be called multiple times from multiple 271C<terminate> or C<cancel> functions. C<join> can be called multiple times
256processes. 272from multiple processes.
257 273
258=cut 274=cut
259 275
260sub join { 276sub join {
261 my $self = shift; 277 my $self = shift;
… …
264 &schedule; 280 &schedule;
265 } 281 }
266 wantarray ? @{$self->{status}} : $self->{status}[0]; 282 wantarray ? @{$self->{status}} : $self->{status}[0];
267} 283}
268 284
269=item $oldprio = $process->prio($newprio) 285=item $oldprio = $process->prio ($newprio)
270 286
271Sets the priority of the process. Higher priority processes get run before 287Sets (or gets, if the argument is missing) the priority of the
288process. Higher priority processes get run before lower priority
272lower priority processes. Priorities are smalled signed integer (currently 289processes. Priorities are small signed integers (currently -4 .. +3),
273-4 .. +3), that you can refer to using PRIO_xxx constants (use the import 290that you can refer to using PRIO_xxx constants (use the import tag :prio
274tag :prio to get then): 291to get then):
275 292
276 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 293 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
277 3 > 1 > 0 > -1 > -3 > -4 294 3 > 1 > 0 > -1 > -3 > -4
278 295
279 # set priority to HIGH 296 # set priority to HIGH
… …
285Changing the priority of the current process will take effect immediately, 302Changing the priority of the current process will take effect immediately,
286but changing the priority of processes in the ready queue (but not 303but changing the priority of processes in the ready queue (but not
287running) will only take effect after the next schedule (of that 304running) will only take effect after the next schedule (of that
288process). This is a bug that will be fixed in some future version. 305process). This is a bug that will be fixed in some future version.
289 306
290=cut
291
292sub prio {
293 my $old = $_[0]{prio};
294 $_[0]{prio} = $_[1] if @_ > 1;
295 $old;
296}
297
298=item $newprio = $process->nice($change) 307=item $newprio = $process->nice ($change)
299 308
300Similar to C<prio>, but subtract the given value from the priority (i.e. 309Similar to C<prio>, but subtract the given value from the priority (i.e.
301higher values mean lower priority, just as in unix). 310higher values mean lower priority, just as in unix).
302 311
303=cut 312=item $olddesc = $process->desc ($newdesc)
304 313
305sub nice { 314Sets (or gets in case the argument is missing) the description for this
306 $_[0]{prio} -= $_[1]; 315process. This is just a free-form string you can associate with a process.
316
317=cut
318
319sub desc {
320 my $old = $_[0]{desc};
321 $_[0]{desc} = $_[1] if @_ > 1;
322 $old;
307} 323}
308 324
309=back 325=back
310 326
311=cut 327=cut
312 328
3131; 3291;
314 330
315=head1 BUGS/LIMITATIONS 331=head1 BUGS/LIMITATIONS
316 332
317 - you must make very sure that no coro is still active on global destruction. 333 - you must make very sure that no coro is still active on global
318 very bad things might happen otherwise (usually segfaults). 334 destruction. very bad things might happen otherwise (usually segfaults).
335
319 - this module is not thread-safe. You must only ever use this module from 336 - this module is not thread-safe. You should only ever use this module
320 the same thread (this requirement might be loosened in the future to 337 from the same thread (this requirement might be losened in the future
321 allow per-thread schedulers, but Coro::State does not yet allow this). 338 to allow per-thread schedulers, but Coro::State does not yet allow
339 this).
322 340
323=head1 SEE ALSO 341=head1 SEE ALSO
324 342
325L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 343Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
326L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 344
327L<Coro::Handle>, L<Coro::Socket>. 345Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
346
347Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
348
349Embedding: L<Coro:MakeMaker>
328 350
329=head1 AUTHOR 351=head1 AUTHOR
330 352
331 Marc Lehmann <pcg@goof.com> 353 Marc Lehmann <schmorp@schmorp.de>
332 http://www.goof.com/pcg/marc/ 354 http://home.schmorp.de/
333 355
334=cut 356=cut
335 357

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