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Revision 1.32 by root, Sun Sep 2 01:03:53 2001 UTC vs.
Revision 1.90 by root, Thu Nov 30 18:21:14 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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35use strict;
36no warnings "uninitialized";
37
37use Coro::State; 38use Coro::State;
38 39
39use base Exporter; 40use base qw(Coro::State Exporter);
40 41
41$VERSION = 0.49; 42our $idle; # idle handler
43our $main; # main coroutine
44our $current; # current coroutine
42 45
46our $VERSION = '3.0';
47
43@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
44%EXPORT_TAGS = ( 49our %EXPORT_TAGS = (
45 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
46); 51);
47@EXPORT_OK = @{$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
101is C<$main> (of course).
102
103This variable is B<strictly> I<read-only>. It is provided for performance
104reasons. If performance is not essentiel you are encouraged to use the
105C<Coro::current> function instead.
91 106
92=cut 107=cut
93 108
94# maybe some other module used Coro::Specific before... 109# maybe some other module used Coro::Specific before...
95if ($current) { 110if ($current) {
96 $main->{specific} = $current->{specific}; 111 $main->{specific} = $current->{specific};
97} 112}
98 113
99our $current = $main; 114$current = $main;
100 115
101sub current() { $current } 116sub current() { $current }
102 117
103=item $idle 118=item $idle
104 119
105The coroutine to switch to when no other coroutine is running. The default 120A callback that is called whenever the scheduler finds no ready coroutines
106implementation prints "FATAL: deadlock detected" and exits. 121to run. The default implementation prints "FATAL: deadlock detected" and
122exits.
107 123
108=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.
109 127
110# should be done using priorities :( 128=cut
111our $idle = new Coro sub { 129
130$idle = sub {
112 print STDERR "FATAL: deadlock detected\n"; 131 print STDERR "FATAL: deadlock detected\n";
113 exit(51); 132 exit (51);
114}; 133};
115 134
116# this coroutine is necessary because a coroutine 135# this coroutine is necessary because a coroutine
117# cannot destroy itself. 136# cannot destroy itself.
118my @destroy; 137my @destroy;
119my $manager = new Coro sub { 138my $manager; $manager = new Coro sub {
120 while() { 139 while () {
121 delete ((pop @destroy)->{_coro_state}) while @destroy; 140 # by overwriting the state object with the manager we destroy it
141 # while still being able to schedule this coroutine (in case it has
142 # been readied multiple times. this is harmless since the manager
143 # can be called as many times as neccessary and will always
144 # remove itself from the runqueue
145 while (@destroy) {
146 my $coro = pop @destroy;
147 $coro->{status} ||= [];
148 $_->ready for @{delete $coro->{join} || []};
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);
155 }
122 &schedule; 156 &schedule;
123 } 157 }
124}; 158};
125 159
126# static methods. not really. 160# static methods. not really.
127 161
162=back
163
128=head2 STATIC METHODS 164=head2 STATIC METHODS
129 165
130Static methods are actually functions that operate on the current process only. 166Static methods are actually functions that operate on the current process only.
131 167
132=over 4 168=over 4
… …
134=item async { ... } [@args...] 170=item async { ... } [@args...]
135 171
136Create a new asynchronous process and return it's process object 172Create a new asynchronous process and return it's process object
137(usually unused). When the sub returns the new process is automatically 173(usually unused). When the sub returns the new process is automatically
138terminated. 174terminated.
175
176Calling C<exit> in a coroutine will not work correctly, so do not do that.
177
178When the coroutine dies, the program will exit, just as in the main
179program.
139 180
140 # create a new coroutine that just prints its arguments 181 # create a new coroutine that just prints its arguments
141 async { 182 async {
142 print "@_\n"; 183 print "@_\n";
143 } 1,2,3,4; 184 } 1,2,3,4;
144 185
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
148=cut 186=cut
149 187
150sub async(&@) { 188sub async(&@) {
151 my $pid = new Coro @_; 189 my $pid = new Coro @_;
152 $manager->ready; # this ensures that the stack is cloned from the manager
153 $pid->ready; 190 $pid->ready;
154 $pid; 191 $pid
155} 192}
156 193
157=item schedule 194=item schedule
158 195
159Calls the scheduler. Please note that the current process will not be put 196Calls the scheduler. Please note that the current process will not be put
… …
168ready queue and calls C<schedule>, which has the effect of giving up the 205ready queue and calls C<schedule>, which has the effect of giving up the
169current "timeslice" to other coroutines of the same or higher priority. 206current "timeslice" to other coroutines of the same or higher priority.
170 207
171=cut 208=cut
172 209
173=item terminate 210=item terminate [arg...]
174 211
175Terminates the current process. 212Terminates the current process with the given status values (see L<cancel>).
176
177Future versions of this function will allow result arguments.
178 213
179=cut 214=cut
180 215
181sub terminate { 216sub terminate {
182 $current->cancel; 217 $current->cancel (@_);
183 &schedule;
184 die; # NORETURN
185} 218}
186 219
187=back 220=back
188 221
189# dynamic methods 222# dynamic methods
… …
195=over 4 228=over 4
196 229
197=item new Coro \&sub [, @args...] 230=item new Coro \&sub [, @args...]
198 231
199Create a new process and return it. When the sub returns the process 232Create a new process and return it. When the sub returns the process
200automatically terminates. To start the process you must first put it into 233automatically terminates as if C<terminate> with the returned values were
234called. To make the process run you must first put it into the ready queue
201the ready queue by calling the ready method. 235by calling the ready method.
202 236
203The coderef you submit MUST NOT be a closure that refers to variables 237Calling C<exit> in a coroutine will not work correctly, so do not do that.
204in an outer scope. This does NOT work. Pass arguments into it instead.
205 238
206=cut 239=cut
207 240
208sub _newcoro { 241sub _new_coro {
209 terminate &{+shift}; 242 terminate &{+shift};
210} 243}
211 244
212sub new { 245sub new {
213 my $class = shift; 246 my $class = shift;
214 bless {
215 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
216 }, $class;
217}
218 247
248 $class->SUPER::new (\&_new_coro, @_)
249}
250
219=item $process->ready 251=item $success = $process->ready
220 252
221Put the current process into the ready queue. 253Put the given process into the ready queue (according to it's priority)
254and return true. If the process is already in the ready queue, do nothing
255and return false.
222 256
223=cut 257=item $is_ready = $process->is_ready
224 258
259Return wether the process is currently the ready queue or not,
260
225=item $process->cancel 261=item $process->cancel (arg...)
226 262
227Like C<terminate>, but terminates the specified process instead. 263Terminates the given process and makes it return the given arguments as
264status (default: the empty list).
228 265
229=cut 266=cut
230 267
231sub cancel { 268sub cancel {
269 my $self = shift;
270 $self->{status} = [@_];
232 push @destroy, $_[0]; 271 push @destroy, $self;
233 $manager->ready; 272 $manager->ready;
273 &schedule if $current == $self;
234} 274}
235 275
276=item $process->join
277
278Wait until the coroutine terminates and return any values given to the
279C<terminate> or C<cancel> functions. C<join> can be called multiple times
280from multiple processes.
281
282=cut
283
284sub join {
285 my $self = shift;
286 unless ($self->{status}) {
287 push @{$self->{join}}, $current;
288 &schedule;
289 }
290 wantarray ? @{$self->{status}} : $self->{status}[0];
291}
292
236=item $oldprio = $process->prio($newprio) 293=item $oldprio = $process->prio ($newprio)
237 294
238Sets the priority of the process. Higher priority processes get run before 295Sets (or gets, if the argument is missing) the priority of the
296process. Higher priority processes get run before lower priority
239lower priority processes. Priorities are smalled signed integer (currently 297processes. Priorities are small signed integers (currently -4 .. +3),
240-4 .. +3), that you can refer to using PRIO_xxx constants (use the import 298that you can refer to using PRIO_xxx constants (use the import tag :prio
241tag :prio to get then): 299to get then):
242 300
243 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 301 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
244 3 > 1 > 0 > -1 > -3 > -4 302 3 > 1 > 0 > -1 > -3 > -4
245 303
246 # set priority to HIGH 304 # set priority to HIGH
… …
252Changing the priority of the current process will take effect immediately, 310Changing the priority of the current process will take effect immediately,
253but changing the priority of processes in the ready queue (but not 311but changing the priority of processes in the ready queue (but not
254running) will only take effect after the next schedule (of that 312running) will only take effect after the next schedule (of that
255process). This is a bug that will be fixed in some future version. 313process). This is a bug that will be fixed in some future version.
256 314
257=cut
258
259sub prio {
260 my $old = $_[0]{prio};
261 $_[0]{prio} = $_[1] if @_ > 1;
262 $old;
263}
264
265=item $newprio = $process->nice($change) 315=item $newprio = $process->nice ($change)
266 316
267Similar to C<prio>, but subtract the given value from the priority (i.e. 317Similar to C<prio>, but subtract the given value from the priority (i.e.
268higher values mean lower priority, just as in unix). 318higher values mean lower priority, just as in unix).
269 319
270=cut 320=item $olddesc = $process->desc ($newdesc)
271 321
272sub nice { 322Sets (or gets in case the argument is missing) the description for this
273 $_[0]{prio} -= $_[1]; 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;
274} 331}
275 332
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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