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Revision 1.34 by root, Sun Sep 16 01:34:35 2001 UTC vs.
Revision 1.83 by root, Fri Nov 24 15:34:33 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
42our $idle; # idle handler
43our $main; # main coroutine
44our $current; # current coroutine
45
41$VERSION = 0.5; 46our $VERSION = '2.5';
42 47
43@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
44%EXPORT_TAGS = ( 49our %EXPORT_TAGS = (
45 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
46); 51);
47@EXPORT_OK = @{$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;
138my $manager;
119my $manager = new Coro sub { 139$manager = new Coro sub {
120 while() { 140 while () {
121 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 }
122 &schedule; 157 &schedule;
123 } 158 }
124}; 159};
125 160
126# static methods. not really. 161# static methods. not really.
127 162
163=back
164
128=head2 STATIC METHODS 165=head2 STATIC METHODS
129 166
130Static methods are actually functions that operate on the current process only. 167Static methods are actually functions that operate on the current process only.
131 168
132=over 4 169=over 4
… …
134=item async { ... } [@args...] 171=item async { ... } [@args...]
135 172
136Create a new asynchronous process and return it's process object 173Create a new asynchronous process and return it's process object
137(usually unused). When the sub returns the new process is automatically 174(usually unused). When the sub returns the new process is automatically
138terminated. 175terminated.
176
177When the coroutine dies, the program will exit, just as in the main
178program.
139 179
140 # create a new coroutine that just prints its arguments 180 # create a new coroutine that just prints its arguments
141 async { 181 async {
142 print "@_\n"; 182 print "@_\n";
143 } 1,2,3,4; 183 } 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.
147 184
148=cut 185=cut
149 186
150sub async(&@) { 187sub async(&@) {
151 my $pid = new Coro @_; 188 my $pid = new Coro @_;
… …
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
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.
205 236
206=cut 237=cut
207 238
208sub _newcoro { 239sub _newcoro {
209 terminate &{+shift}; 240 terminate &{+shift};
210} 241}
211 242
212sub new { 243sub new {
213 my $class = shift; 244 my $class = shift;
214 bless { 245
215 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 246 $class->SUPER::new (\&_newcoro, @_)
216 }, $class;
217} 247}
218 248
219=item $process->ready 249=item $process->ready
220 250
221Put the current process into the ready queue. 251Put the given process into the ready queue.
222 252
223=cut 253=cut
224 254
225=item $process->cancel 255=item $process->cancel (arg...)
226 256
227Like C<terminate>, but terminates the specified process instead. 257Terminates the given process and makes it return the given arguments as
258status (default: the empty list).
228 259
229=cut 260=cut
230 261
231sub cancel { 262sub cancel {
263 my $self = shift;
264 $self->{status} = [@_];
232 push @destroy, $_[0]; 265 push @destroy, $self;
233 $manager->ready; 266 $manager->ready;
267 &schedule if $current == $self;
234} 268}
235 269
270=item $process->join
271
272Wait until the coroutine terminates and return any values given to the
273C<terminate> or C<cancel> functions. C<join> can be called multiple times
274from multiple processes.
275
276=cut
277
278sub join {
279 my $self = shift;
280 unless ($self->{status}) {
281 push @{$self->{join}}, $current;
282 &schedule;
283 }
284 wantarray ? @{$self->{status}} : $self->{status}[0];
285}
286
236=item $oldprio = $process->prio($newprio) 287=item $oldprio = $process->prio ($newprio)
237 288
238Sets the priority of the process. Higher priority processes get run before 289Sets (or gets, if the argument is missing) the priority of the
290process. Higher priority processes get run before lower priority
239lower priority processes. Priorities are smalled signed integer (currently 291processes. Priorities are small signed integers (currently -4 .. +3),
240-4 .. +3), that you can refer to using PRIO_xxx constants (use the import 292that you can refer to using PRIO_xxx constants (use the import tag :prio
241tag :prio to get then): 293to get then):
242 294
243 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 295 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
244 3 > 1 > 0 > -1 > -3 > -4 296 3 > 1 > 0 > -1 > -3 > -4
245 297
246 # set priority to HIGH 298 # set priority to HIGH
… …
252Changing the priority of the current process will take effect immediately, 304Changing the priority of the current process will take effect immediately,
253but changing the priority of processes in the ready queue (but not 305but changing the priority of processes in the ready queue (but not
254running) will only take effect after the next schedule (of that 306running) will only take effect after the next schedule (of that
255process). This is a bug that will be fixed in some future version. 307process). This is a bug that will be fixed in some future version.
256 308
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) 309=item $newprio = $process->nice ($change)
266 310
267Similar to C<prio>, but subtract the given value from the priority (i.e. 311Similar to C<prio>, but subtract the given value from the priority (i.e.
268higher values mean lower priority, just as in unix). 312higher values mean lower priority, just as in unix).
269 313
270=cut 314=item $olddesc = $process->desc ($newdesc)
271 315
272sub nice { 316Sets (or gets in case the argument is missing) the description for this
273 $_[0]{prio} -= $_[1]; 317process. This is just a free-form string you can associate with a process.
318
319=cut
320
321sub desc {
322 my $old = $_[0]{desc};
323 $_[0]{desc} = $_[1] if @_ > 1;
324 $old;
274} 325}
275 326
276=back 327=back
277 328
278=cut 329=cut
279 330
2801; 3311;
281 332
282=head1 BUGS/LIMITATIONS 333=head1 BUGS/LIMITATIONS
283 334
284 - you must make very sure that no coro is still active on global destruction. 335 - you must make very sure that no coro is still active on global
285 very bad things might happen otherwise (usually segfaults). 336 destruction. very bad things might happen otherwise (usually segfaults).
337
286 - this module is not thread-safe. You must only ever use this module from 338 - this module is not thread-safe. You should only ever use this module
287 the same thread (this requirement might be loosened in the future to 339 from the same thread (this requirement might be losened in the future
288 allow per-thread schedulers, but Coro::State does not yet allow this). 340 to allow per-thread schedulers, but Coro::State does not yet allow
341 this).
289 342
290=head1 SEE ALSO 343=head1 SEE ALSO
291 344
292L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 345Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
293L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 346
294L<Coro::Handle>, L<Coro::Socket>. 347Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
348
349Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
350
351Embedding: L<Coro:MakeMaker>
295 352
296=head1 AUTHOR 353=head1 AUTHOR
297 354
298 Marc Lehmann <pcg@goof.com> 355 Marc Lehmann <schmorp@schmorp.de>
299 http://www.goof.com/pcg/marc/ 356 http://home.schmorp.de/
300 357
301=cut 358=cut
302 359

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