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Revision 1.30 by root, Sat Aug 11 19:59:19 2001 UTC vs.
Revision 1.86 by root, Sat Nov 25 01:14:11 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 = 0.45; 46our $VERSION = '2.5';
42 47
43@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
44@EXPORT_OK = qw($current); 49our %EXPORT_TAGS = (
50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51);
52our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
45 53
46{ 54{
47 my @async; 55 my @async;
48 my $init; 56 my $init;
49 57
50 # this way of handling attributes simply is NOT scalable ;() 58 # this way of handling attributes simply is NOT scalable ;()
51 sub import { 59 sub import {
60 no strict 'refs';
61
52 Coro->export_to_level(1, @_); 62 Coro->export_to_level(1, @_);
63
53 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 64 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
54 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { 65 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
55 my ($package, $ref) = (shift, shift); 66 my ($package, $ref) = (shift, shift);
56 my @attrs; 67 my @attrs;
57 for (@_) { 68 for (@_) {
… …
72 }; 83 };
73 } 84 }
74 85
75} 86}
76 87
88=over 4
89
77=item $main 90=item $main
78 91
79This coroutine represents the main program. 92This coroutine represents the main program.
80 93
81=cut 94=cut
82 95
83our $main = new Coro; 96$main = new Coro;
84 97
85=item $current (or as function: current) 98=item $current (or as function: current)
86 99
87The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 100The current coroutine (the last coroutine switched to). The initial value
101is C<$main> (of course).
102
103This variable is B<strictly> I<read-only>. It is provided for performance
104reasons. If performance is not essentiel you are encouraged to use the
105C<Coro::current> function instead.
88 106
89=cut 107=cut
90 108
91# maybe some other module used Coro::Specific before... 109# maybe some other module used Coro::Specific before...
92if ($current) { 110if ($current) {
93 $main->{specific} = $current->{specific}; 111 $main->{specific} = $current->{specific};
94} 112}
95 113
96our $current = $main; 114$current = $main;
97 115
98sub current() { $current } 116sub current() { $current }
99 117
100=item $idle 118=item $idle
101 119
102The coroutine to switch to when no other coroutine is running. The default 120A callback that is called whenever the scheduler finds no ready coroutines
103implementation prints "FATAL: deadlock detected" and exits. 121to run. The default implementation prints "FATAL: deadlock detected" and
122exits.
104 123
105=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.
106 127
107# should be done using priorities :( 128=cut
108our $idle = new Coro sub { 129
130$idle = sub {
109 print STDERR "FATAL: deadlock detected\n"; 131 print STDERR "FATAL: deadlock detected\n";
110 exit(51); 132 exit (51);
111}; 133};
112 134
113# this coroutine is necessary because a coroutine 135# this coroutine is necessary because a coroutine
114# cannot destroy itself. 136# cannot destroy itself.
115my @destroy; 137my @destroy;
116my $manager = new Coro sub { 138my $manager; $manager = new Coro sub {
117 while() { 139 while () {
118 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 }
119 &schedule; 156 &schedule;
120 } 157 }
121}; 158};
122 159
123# static methods. not really. 160# static methods. not really.
124 161
162=back
163
125=head2 STATIC METHODS 164=head2 STATIC METHODS
126 165
127Static methods are actually functions that operate on the current process only. 166Static methods are actually functions that operate on the current process only.
128 167
129=over 4 168=over 4
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131=item async { ... } [@args...] 170=item async { ... } [@args...]
132 171
133Create a new asynchronous process and return it's process object 172Create a new asynchronous process and return it's process object
134(usually unused). When the sub returns the new process is automatically 173(usually unused). When the sub returns the new process is automatically
135terminated. 174terminated.
175
176When the coroutine dies, the program will exit, just as in the main
177program.
136 178
137 # create a new coroutine that just prints its arguments 179 # create a new coroutine that just prints its arguments
138 async { 180 async {
139 print "@_\n"; 181 print "@_\n";
140 } 1,2,3,4; 182 } 1,2,3,4;
141 183
142The coderef you submit MUST NOT be a closure that refers to variables
143in an outer scope. This does NOT work. Pass arguments into it instead.
144
145=cut 184=cut
146 185
147sub async(&@) { 186sub async(&@) {
148 my $pid = new Coro @_; 187 my $pid = new Coro @_;
149 $manager->ready; # this ensures that the stack is cloned from the manager
150 $pid->ready; 188 $pid->ready;
151 $pid; 189 $pid
152} 190}
153 191
154=item schedule 192=item schedule
155 193
156Calls 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
… …
165ready 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
166current "timeslice" to other coroutines of the same or higher priority. 204current "timeslice" to other coroutines of the same or higher priority.
167 205
168=cut 206=cut
169 207
170=item terminate 208=item terminate [arg...]
171 209
172Terminates the current process. 210Terminates the current process with the given status values (see L<cancel>).
173
174Future versions of this function will allow result arguments.
175 211
176=cut 212=cut
177 213
178sub terminate { 214sub terminate {
179 $current->cancel; 215 $current->cancel (@_);
180 &schedule;
181 die; # NORETURN
182} 216}
183 217
184=back 218=back
185 219
186# dynamic methods 220# dynamic methods
… …
192=over 4 226=over 4
193 227
194=item new Coro \&sub [, @args...] 228=item new Coro \&sub [, @args...]
195 229
196Create 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
197automatically 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
198the ready queue by calling the ready method. 233by calling the ready method.
199 234
200The coderef you submit MUST NOT be a closure that refers to variables
201in an outer scope. This does NOT work. Pass arguments into it instead.
202
203=cut 235=cut
204 236
205sub _newcoro { 237sub _new_coro {
238 $current->_clear_idle_sp; # (re-)set the idle sp on the following cede
239 _set_cede_self; # ensures that cede cede's us first
240 cede;
206 terminate &{+shift}; 241 terminate &{+shift};
207} 242}
208 243
209sub new { 244sub new {
210 my $class = shift; 245 my $class = shift;
211 bless { 246
212 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 247 $class->SUPER::new (\&_new_coro, @_)
213 }, $class;
214} 248}
215 249
216=item $process->ready 250=item $process->ready
217 251
218Put the current process into the ready queue. 252Put the given process into the ready queue.
219 253
220=cut 254=cut
221 255
222=item $process->cancel 256=item $process->cancel (arg...)
223 257
224Like C<terminate>, but terminates the specified process instead. 258Terminates the given process and makes it return the given arguments as
259status (default: the empty list).
225 260
226=cut 261=cut
227 262
228sub cancel { 263sub cancel {
264 my $self = shift;
265 $self->{status} = [@_];
229 push @destroy, $_[0]; 266 push @destroy, $self;
230 $manager->ready; 267 $manager->ready;
268 &schedule if $current == $self;
269}
270
271=item $process->join
272
273Wait until the coroutine terminates and return any values given to the
274C<terminate> or C<cancel> functions. C<join> can be called multiple times
275from multiple processes.
276
277=cut
278
279sub join {
280 my $self = shift;
281 unless ($self->{status}) {
282 push @{$self->{join}}, $current;
283 &schedule;
284 }
285 wantarray ? @{$self->{status}} : $self->{status}[0];
286}
287
288=item $oldprio = $process->prio ($newprio)
289
290Sets (or gets, if the argument is missing) the priority of the
291process. Higher priority processes get run before lower priority
292processes. Priorities are small signed integers (currently -4 .. +3),
293that you can refer to using PRIO_xxx constants (use the import tag :prio
294to get then):
295
296 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
297 3 > 1 > 0 > -1 > -3 > -4
298
299 # set priority to HIGH
300 current->prio(PRIO_HIGH);
301
302The idle coroutine ($Coro::idle) always has a lower priority than any
303existing coroutine.
304
305Changing the priority of the current process will take effect immediately,
306but changing the priority of processes in the ready queue (but not
307running) will only take effect after the next schedule (of that
308process). This is a bug that will be fixed in some future version.
309
310=item $newprio = $process->nice ($change)
311
312Similar to C<prio>, but subtract the given value from the priority (i.e.
313higher values mean lower priority, just as in unix).
314
315=item $olddesc = $process->desc ($newdesc)
316
317Sets (or gets in case the argument is missing) the description for this
318process. This is just a free-form string you can associate with a process.
319
320=cut
321
322sub desc {
323 my $old = $_[0]{desc};
324 $_[0]{desc} = $_[1] if @_ > 1;
325 $old;
231} 326}
232 327
233=back 328=back
234 329
235=cut 330=cut
236 331
2371; 3321;
238 333
239=head1 BUGS/LIMITATIONS 334=head1 BUGS/LIMITATIONS
240 335
241 - could be faster, especially when the core would introduce special 336 - you must make very sure that no coro is still active on global
242 support for coroutines (like it does for threads). 337 destruction. very bad things might happen otherwise (usually segfaults).
243 - there is still a memleak on coroutine termination that I could not 338
244 identify. Could be as small as a single SV.
245 - this module is not well-tested.
246 - if variables or arguments "disappear" (become undef) or become
247 corrupted please contact the author so he cen iron out the
248 remaining bugs.
249 - this module is not thread-safe. You must only ever use this module from 339 - this module is not thread-safe. You should only ever use this module
250 the same thread (this requirement might be loosened in the future to 340 from the same thread (this requirement might be losened in the future
251 allow per-thread schedulers, but Coro::State does not yet allow this). 341 to allow per-thread schedulers, but Coro::State does not yet allow
342 this).
252 343
253=head1 SEE ALSO 344=head1 SEE ALSO
254 345
255L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 346Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
256L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 347
257L<Coro::Handle>, L<Coro::Socket>. 348Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
349
350Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
351
352Embedding: L<Coro:MakeMaker>
258 353
259=head1 AUTHOR 354=head1 AUTHOR
260 355
261 Marc Lehmann <pcg@goof.com> 356 Marc Lehmann <schmorp@schmorp.de>
262 http://www.goof.com/pcg/marc/ 357 http://home.schmorp.de/
263 358
264=cut 359=cut
265 360

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