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Revision 1.36 by root, Mon Sep 24 01:36:20 2001 UTC vs.
Revision 1.85 by root, Sat Nov 25 00:56:35 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;
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
42our $idle; # idle handler
43our $main; # main coroutine
44our $current; # current coroutine
45
43$VERSION = 0.5; 46our $VERSION = '2.5';
44 47
45@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
46%EXPORT_TAGS = ( 49our %EXPORT_TAGS = (
47 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48); 51);
49@EXPORT_OK = @{$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;
138my $manager;
121my $manager = new Coro sub { 139$manager = new Coro sub {
122 while() { 140 while () {
123 delete ((pop @destroy)->{_coro_state}) while @destroy; 141 # by overwriting the state object with the manager we destroy it
142 # while still being able to schedule this coroutine (in case it has
143 # been readied multiple times. this is harmless since the manager
144 # can be called as many times as neccessary and will always
145 # remove itself from the runqueue
146 while (@destroy) {
147 my $coro = pop @destroy;
148 $coro->{status} ||= [];
149 $_->ready for @{delete $coro->{join} || []};
150
151 # the next line destroys the coro state, but keeps the
152 # process itself intact (we basically make it a zombie
153 # process that always runs the manager thread, so it's possible
154 # to transfer() to this process).
155 $coro->_clone_state_from ($manager);
156 }
124 &schedule; 157 &schedule;
125 } 158 }
126}; 159};
127 160
128# static methods. not really. 161# static methods. not really.
129 162
163=back
164
130=head2 STATIC METHODS 165=head2 STATIC METHODS
131 166
132Static methods are actually functions that operate on the current process only. 167Static methods are actually functions that operate on the current process only.
133 168
134=over 4 169=over 4
… …
136=item async { ... } [@args...] 171=item async { ... } [@args...]
137 172
138Create a new asynchronous process and return it's process object 173Create a new asynchronous process and return it's process object
139(usually unused). When the sub returns the new process is automatically 174(usually unused). When the sub returns the new process is automatically
140terminated. 175terminated.
176
177When the coroutine dies, the program will exit, just as in the main
178program.
141 179
142 # create a new coroutine that just prints its arguments 180 # create a new coroutine that just prints its arguments
143 async { 181 async {
144 print "@_\n"; 182 print "@_\n";
145 } 1,2,3,4; 183 } 1,2,3,4;
146 184
147The coderef you submit MUST NOT be a closure that refers to variables
148in an outer scope. This does NOT work. Pass arguments into it instead.
149
150=cut 185=cut
151 186
152sub async(&@) { 187sub async(&@) {
153 my $pid = new Coro @_; 188 my $pid = new Coro @_;
154 $manager->ready; # this ensures that the stack is cloned from the manager
155 $pid->ready; 189 $pid->ready;
156 $pid; 190 $pid
157} 191}
158 192
159=item schedule 193=item schedule
160 194
161Calls the scheduler. Please note that the current process will not be put 195Calls the scheduler. Please note that the current process will not be put
… …
170ready queue and calls C<schedule>, which has the effect of giving up the 204ready queue and calls C<schedule>, which has the effect of giving up the
171current "timeslice" to other coroutines of the same or higher priority. 205current "timeslice" to other coroutines of the same or higher priority.
172 206
173=cut 207=cut
174 208
175=item terminate 209=item terminate [arg...]
176 210
177Terminates the current process. 211Terminates the current process with the given status values (see L<cancel>).
178
179Future versions of this function will allow result arguments.
180 212
181=cut 213=cut
182 214
183sub terminate { 215sub terminate {
184 $current->cancel; 216 $current->cancel (@_);
185 &schedule;
186 die; # NORETURN
187} 217}
188 218
189=back 219=back
190 220
191# dynamic methods 221# dynamic methods
… …
197=over 4 227=over 4
198 228
199=item new Coro \&sub [, @args...] 229=item new Coro \&sub [, @args...]
200 230
201Create a new process and return it. When the sub returns the process 231Create a new process and return it. When the sub returns the process
202automatically terminates. To start the process you must first put it into 232automatically terminates as if C<terminate> with the returned values were
233called. To make the process run you must first put it into the ready queue
203the ready queue by calling the ready method. 234by calling the ready method.
204 235
205The coderef you submit MUST NOT be a closure that refers to variables
206in an outer scope. This does NOT work. Pass arguments into it instead.
207
208=cut 236=cut
209 237
210sub _newcoro { 238sub _new_coro {
239 $current->_clear_idle_sp; # set the idle sp on the following cede
240 _set_cede_self; # ensures that cede cede's us first
241 cede;
211 terminate &{+shift}; 242 terminate &{+shift};
212} 243}
213 244
214sub new { 245sub new {
215 my $class = shift; 246 my $class = shift;
216 bless { 247
217 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 248 $class->SUPER::new (\&_new_coro, @_)
218 }, $class;
219} 249}
220 250
221=item $process->ready 251=item $process->ready
222 252
223Put the current process into the ready queue. 253Put the given process into the ready queue.
224 254
225=cut 255=cut
226 256
227=item $process->cancel 257=item $process->cancel (arg...)
228 258
229Like C<terminate>, but terminates the specified process instead. 259Terminates the given process and makes it return the given arguments as
260status (default: the empty list).
230 261
231=cut 262=cut
232 263
233sub cancel { 264sub cancel {
265 my $self = shift;
266 $self->{status} = [@_];
234 push @destroy, $_[0]; 267 push @destroy, $self;
235 $manager->ready; 268 $manager->ready;
236 &schedule if $current == $_[0]; 269 &schedule if $current == $self;
237} 270}
238 271
272=item $process->join
273
274Wait until the coroutine terminates and return any values given to the
275C<terminate> or C<cancel> functions. C<join> can be called multiple times
276from multiple processes.
277
278=cut
279
280sub join {
281 my $self = shift;
282 unless ($self->{status}) {
283 push @{$self->{join}}, $current;
284 &schedule;
285 }
286 wantarray ? @{$self->{status}} : $self->{status}[0];
287}
288
239=item $oldprio = $process->prio($newprio) 289=item $oldprio = $process->prio ($newprio)
240 290
241Sets the priority of the process. Higher priority processes get run before 291Sets (or gets, if the argument is missing) the priority of the
292process. Higher priority processes get run before lower priority
242lower priority processes. Priorities are smalled signed integer (currently 293processes. Priorities are small signed integers (currently -4 .. +3),
243-4 .. +3), that you can refer to using PRIO_xxx constants (use the import 294that you can refer to using PRIO_xxx constants (use the import tag :prio
244tag :prio to get then): 295to get then):
245 296
246 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 297 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
247 3 > 1 > 0 > -1 > -3 > -4 298 3 > 1 > 0 > -1 > -3 > -4
248 299
249 # set priority to HIGH 300 # set priority to HIGH
… …
255Changing the priority of the current process will take effect immediately, 306Changing the priority of the current process will take effect immediately,
256but changing the priority of processes in the ready queue (but not 307but changing the priority of processes in the ready queue (but not
257running) will only take effect after the next schedule (of that 308running) will only take effect after the next schedule (of that
258process). This is a bug that will be fixed in some future version. 309process). This is a bug that will be fixed in some future version.
259 310
260=cut
261
262sub prio {
263 my $old = $_[0]{prio};
264 $_[0]{prio} = $_[1] if @_ > 1;
265 $old;
266}
267
268=item $newprio = $process->nice($change) 311=item $newprio = $process->nice ($change)
269 312
270Similar to C<prio>, but subtract the given value from the priority (i.e. 313Similar to C<prio>, but subtract the given value from the priority (i.e.
271higher values mean lower priority, just as in unix). 314higher values mean lower priority, just as in unix).
272 315
273=cut 316=item $olddesc = $process->desc ($newdesc)
274 317
275sub nice { 318Sets (or gets in case the argument is missing) the description for this
276 $_[0]{prio} -= $_[1]; 319process. This is just a free-form string you can associate with a process.
320
321=cut
322
323sub desc {
324 my $old = $_[0]{desc};
325 $_[0]{desc} = $_[1] if @_ > 1;
326 $old;
277} 327}
278 328
279=back 329=back
280 330
281=cut 331=cut
282 332
2831; 3331;
284 334
285=head1 BUGS/LIMITATIONS 335=head1 BUGS/LIMITATIONS
286 336
287 - you must make very sure that no coro is still active on global destruction. 337 - you must make very sure that no coro is still active on global
288 very bad things might happen otherwise (usually segfaults). 338 destruction. very bad things might happen otherwise (usually segfaults).
339
289 - this module is not thread-safe. You must only ever use this module from 340 - this module is not thread-safe. You should only ever use this module
290 the same thread (this requirement might be loosened in the future to 341 from the same thread (this requirement might be losened in the future
291 allow per-thread schedulers, but Coro::State does not yet allow this). 342 to allow per-thread schedulers, but Coro::State does not yet allow
343 this).
292 344
293=head1 SEE ALSO 345=head1 SEE ALSO
294 346
295L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 347Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
296L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 348
297L<Coro::Handle>, L<Coro::Socket>. 349Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
350
351Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
352
353Embedding: L<Coro:MakeMaker>
298 354
299=head1 AUTHOR 355=head1 AUTHOR
300 356
301 Marc Lehmann <pcg@goof.com> 357 Marc Lehmann <schmorp@schmorp.de>
302 http://www.goof.com/pcg/marc/ 358 http://home.schmorp.de/
303 359
304=cut 360=cut
305 361

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