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Revision 1.33 by root, Sun Sep 16 00:44:05 2001 UTC vs.
Revision 1.88 by root, Sun Nov 26 02:54:55 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
176When the coroutine dies, the program will exit, just as in the main
177program.
139 178
140 # create a new coroutine that just prints its arguments 179 # create a new coroutine that just prints its arguments
141 async { 180 async {
142 print "@_\n"; 181 print "@_\n";
143 } 1,2,3,4; 182 } 1,2,3,4;
144 183
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 184=cut
149 185
150sub async(&@) { 186sub async(&@) {
151 my $pid = new Coro @_; 187 my $pid = new Coro @_;
152 $manager->ready; # this ensures that the stack is cloned from the manager
153 $pid->ready; 188 $pid->ready;
154 $pid; 189 $pid
155} 190}
156 191
157=item schedule 192=item schedule
158 193
159Calls 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
168ready queue and calls C<schedule>, which has the effect of giving up the 203ready queue and calls C<schedule>, which has the effect of giving up the
169current "timeslice" to other coroutines of the same or higher priority. 204current "timeslice" to other coroutines of the same or higher priority.
170 205
171=cut 206=cut
172 207
173=item terminate 208=item terminate [arg...]
174 209
175Terminates the current process. 210Terminates the current process with the given status values (see L<cancel>).
176
177Future versions of this function will allow result arguments.
178 211
179=cut 212=cut
180 213
181sub terminate { 214sub terminate {
182 $current->cancel; 215 $current->cancel (@_);
183 &schedule;
184 die; # NORETURN
185} 216}
186 217
187=back 218=back
188 219
189# dynamic methods 220# dynamic methods
195=over 4 226=over 4
196 227
197=item new Coro \&sub [, @args...] 228=item new Coro \&sub [, @args...]
198 229
199Create 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
200automatically terminates. To start the process you must first put it into 231automatically terminates as if C<terminate> with the returned values were
232called. To make the process run you must first put it into the ready queue
201the ready queue by calling the ready method. 233by calling the ready method.
202 234
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
206=cut 235=cut
207 236
208sub _newcoro { 237sub _new_coro {
209 terminate &{+shift}; 238 terminate &{+shift};
210} 239}
211 240
212sub new { 241sub new {
213 my $class = shift; 242 my $class = shift;
214 bless { 243
215 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 244 $class->SUPER::new (\&_new_coro, @_)
216 }, $class;
217} 245}
218 246
219=item $process->ready 247=item $process->ready
220 248
221Put the current process into the ready queue. 249Put the given process into the ready queue.
222 250
223=cut 251=cut
224 252
225=item $process->cancel 253=item $process->cancel (arg...)
226 254
227Like 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).
228 257
229=cut 258=cut
230 259
231sub cancel { 260sub cancel {
261 my $self = shift;
262 $self->{status} = [@_];
232 push @destroy, $_[0]; 263 push @destroy, $self;
233 $manager->ready; 264 $manager->ready;
265 &schedule if $current == $self;
234} 266}
235 267
268=item $process->join
269
270Wait until the coroutine terminates and return any values given to the
271C<terminate> or C<cancel> functions. C<join> can be called multiple times
272from multiple processes.
273
274=cut
275
276sub join {
277 my $self = shift;
278 unless ($self->{status}) {
279 push @{$self->{join}}, $current;
280 &schedule;
281 }
282 wantarray ? @{$self->{status}} : $self->{status}[0];
283}
284
236=item $oldprio = $process->prio($newprio) 285=item $oldprio = $process->prio ($newprio)
237 286
238Sets 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
239lower priority processes. Priorities are smalled signed integer (currently 289processes. Priorities are small signed integers (currently -4 .. +3),
240-4 .. +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
241tag :prio to get then): 291to get then):
242 292
243 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
244 3 > 1 > 0 > -1 > -3 > -4 294 3 > 1 > 0 > -1 > -3 > -4
245 295
246 # set priority to HIGH 296 # set priority to HIGH
252Changing the priority of the current process will take effect immediately, 302Changing the priority of the current process will take effect immediately,
253but changing the priority of processes in the ready queue (but not 303but changing the priority of processes in the ready queue (but not
254running) will only take effect after the next schedule (of that 304running) will only take effect after the next schedule (of that
255process). 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.
256 306
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) 307=item $newprio = $process->nice ($change)
266 308
267Similar 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.
268higher values mean lower priority, just as in unix). 310higher values mean lower priority, just as in unix).
269 311
270=cut 312=item $olddesc = $process->desc ($newdesc)
271 313
272sub nice { 314Sets (or gets in case the argument is missing) the description for this
273 $_[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;
274} 323}
275 324
276=back 325=back
277 326
278=cut 327=cut
279 328
2801; 3291;
281 330
282=head1 BUGS/LIMITATIONS 331=head1 BUGS/LIMITATIONS
283 332
284 - 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
285 very bad things might happen otherwise (usually segfaults). 334 destruction. very bad things might happen otherwise (usually segfaults).
335
286 - 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
287 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
288 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).
289 340
290=head1 SEE ALSO 341=head1 SEE ALSO
291 342
292L<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>.
293L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 344
294L<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>
295 350
296=head1 AUTHOR 351=head1 AUTHOR
297 352
298 Marc Lehmann <pcg@goof.com> 353 Marc Lehmann <schmorp@schmorp.de>
299 http://www.goof.com/pcg/marc/ 354 http://home.schmorp.de/
300 355
301=cut 356=cut
302 357

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