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Revision 1.22 by root, Mon Jul 23 02:14:19 2001 UTC vs.
Revision 1.38 by root, Wed Oct 3 01:09:56 2001 UTC

… …
24Threads but don't run in parallel. 24Threads but don't run in parallel.
25 25
26This module is still experimental, see the BUGS section below. 26This module is still experimental, see the BUGS section below.
27 27
28In this module, coroutines are defined as "callchain + lexical variables 28In this module, coroutines are defined as "callchain + lexical variables
29+ @_ + $_ + $@ + $^W), that is, a coroutine has it's own callchain, it's 29+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30own set of lexicals and it's own set of perl's most important global 30callchain, it's own set of lexicals and it's own set of perl's most
31variables. 31important global variables.
32
33WARNING: When using this module, make sure that, at program end, no
34coroutines are still running OR just call exit before falling off the
35end. The reason for this is that some coroutine of yours might have called
36into a C function, and falling off the end of main:: results in returning
37to that C function instead if to the main C interpreter.
38
39WARNING: Unless you really know what you are doing, do NOT do context
40switches inside callbacks from the XS level. The reason for this is
41similar to the reason above: A callback calls a perl function, this
42perl function does a context switch, some other callback is called, the
43original function returns from it - to what? To the wrong XS function,
44with totally different return values. Unfortunately, this includes
45callbacks done by perl itself (tie'd variables!).
46
47The only workaround for this is to do coroutines on C level.
48 32
49=cut 33=cut
50 34
51package Coro; 35package Coro;
52 36
37no warnings qw(uninitialized);
38
53use Coro::State; 39use Coro::State;
54 40
55use base Exporter; 41use base Exporter;
56 42
57$VERSION = 0.10; 43$VERSION = 0.51;
58 44
59@EXPORT = qw(async cede schedule terminate current); 45@EXPORT = qw(async cede schedule terminate current);
60@EXPORT_OK = qw($current); 46%EXPORT_TAGS = (
47 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48);
49@EXPORT_OK = @{$EXPORT_TAGS{prio}};
61 50
62{ 51{
63 my @async; 52 my @async;
53 my $init;
64 54
65 # this way of handling attributes simply is NOT scalable ;() 55 # this way of handling attributes simply is NOT scalable ;()
66 sub import { 56 sub import {
67 Coro->export_to_level(1, @_); 57 Coro->export_to_level(1, @_);
68 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 58 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
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70 my ($package, $ref) = (shift, shift); 60 my ($package, $ref) = (shift, shift);
71 my @attrs; 61 my @attrs;
72 for (@_) { 62 for (@_) {
73 if ($_ eq "Coro") { 63 if ($_ eq "Coro") {
74 push @async, $ref; 64 push @async, $ref;
65 unless ($init++) {
66 eval q{
67 sub INIT {
68 &async(pop @async) while @async;
69 }
70 };
71 }
75 } else { 72 } else {
76 push @attrs, $_; 73 push @attrs, $_;
77 } 74 }
78 } 75 }
79 return $old ? $old->($package, $ref, @attrs) : @attrs; 76 return $old ? $old->($package, $ref, @attrs) : @attrs;
80 }; 77 };
81 } 78 }
82 79
83 sub INIT {
84 &async(pop @async) while @async;
85 }
86} 80}
87 81
88=item $main 82=item $main
89 83
90This coroutine represents the main program. 84This coroutine represents the main program.
… …
119our $idle = new Coro sub { 113our $idle = new Coro sub {
120 print STDERR "FATAL: deadlock detected\n"; 114 print STDERR "FATAL: deadlock detected\n";
121 exit(51); 115 exit(51);
122}; 116};
123 117
124# we really need priorities... 118# this coroutine is necessary because a coroutine
125my @ready; # the ready queue. hehe, rather broken ;) 119# cannot destroy itself.
120my @destroy;
121my $manager;
122$manager = new Coro sub {
123 while() {
124 # by overwriting the state object with the manager we destroy it
125 # while still being able to schedule this coroutine (in case it has
126 # been readied multiple times. this is harmless since the manager
127 # can be called as many times as neccessary and will always
128 # remove itself from the runqueue
129 (pop @destroy)->{_coro_state} = $manager->{_coro_state} while @destroy;
130 &schedule;
131 }
132};
126 133
127# static methods. not really. 134# static methods. not really.
128 135
129=head2 STATIC METHODS 136=head2 STATIC METHODS
130 137
… …
148 155
149=cut 156=cut
150 157
151sub async(&@) { 158sub async(&@) {
152 my $pid = new Coro @_; 159 my $pid = new Coro @_;
160 $manager->ready; # this ensures that the stack is cloned from the manager
153 $pid->ready; 161 $pid->ready;
154 $pid; 162 $pid;
155} 163}
156 164
157=item schedule 165=item schedule
… …
160into the ready queue, so calling this function usually means you will 168into the ready queue, so calling this function usually means you will
161never be called again. 169never be called again.
162 170
163=cut 171=cut
164 172
165my $prev;
166
167sub schedule {
168 # should be done using priorities :(
169 ($prev, $current) = ($current, shift @ready || $idle);
170 Coro::State::transfer($prev, $current);
171}
172
173=item cede 173=item cede
174 174
175"Cede" to other processes. This function puts the current process into the 175"Cede" to other processes. This function puts the current process into the
176ready queue and calls C<schedule>, which has the effect of giving up the 176ready queue and calls C<schedule>, which has the effect of giving up the
177current "timeslice" to other coroutines of the same or higher priority. 177current "timeslice" to other coroutines of the same or higher priority.
178 178
179=cut 179=cut
180 180
181sub cede { 181=item terminate
182
183Terminates the current process.
184
185Future versions of this function will allow result arguments.
186
187=cut
188
189sub terminate {
182 $current->ready; 190 $current->cancel;
183 &schedule; 191 &schedule;
184} 192 die; # NORETURN
185
186=item terminate
187
188Terminates the current process.
189
190Future versions of this function will allow result arguments.
191
192=cut
193
194sub terminate {
195 my $self = $current;
196 $self->{_results} = [@_];
197 $current = shift @ready || $idle;
198 Coro::State::transfer(delete $self->{_coro_state}, $current);
199 # cannot return
200 die;
201} 193}
202 194
203=back 195=back
204 196
205# dynamic methods 197# dynamic methods
… …
236 228
237Put the current process into the ready queue. 229Put the current process into the ready queue.
238 230
239=cut 231=cut
240 232
241sub ready { 233=item $process->cancel
234
235Like C<terminate>, but terminates the specified process instead.
236
237=cut
238
239sub cancel {
242 push @ready, $_[0]; 240 push @destroy, $_[0];
241 $manager->ready;
242 &schedule if $current == $_[0];
243}
244
245=item $oldprio = $process->prio($newprio)
246
247Sets the priority of the process. Higher priority processes get run before
248lower priority processes. Priorities are smalled signed integer (currently
249-4 .. +3), that you can refer to using PRIO_xxx constants (use the import
250tag :prio to get then):
251
252 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
253 3 > 1 > 0 > -1 > -3 > -4
254
255 # set priority to HIGH
256 current->prio(PRIO_HIGH);
257
258The idle coroutine ($Coro::idle) always has a lower priority than any
259existing coroutine.
260
261Changing the priority of the current process will take effect immediately,
262but changing the priority of processes in the ready queue (but not
263running) will only take effect after the next schedule (of that
264process). This is a bug that will be fixed in some future version.
265
266=cut
267
268sub prio {
269 my $old = $_[0]{prio};
270 $_[0]{prio} = $_[1] if @_ > 1;
271 $old;
272}
273
274=item $newprio = $process->nice($change)
275
276Similar to C<prio>, but subtract the given value from the priority (i.e.
277higher values mean lower priority, just as in unix).
278
279=cut
280
281sub nice {
282 $_[0]{prio} -= $_[1];
243} 283}
244 284
245=back 285=back
246 286
247=cut 287=cut
248 288
2491; 2891;
250 290
251=head1 BUGS/LIMITATIONS 291=head1 BUGS/LIMITATIONS
252 292
253 - could be faster, especially when the core would introduce special 293 - you must make very sure that no coro is still active on global destruction.
254 support for coroutines (like it does for threads). 294 very bad things might happen otherwise (usually segfaults).
255 - there is still a memleak on coroutine termination that I could not
256 identify. Could be as small as a single SV.
257 - this module is not well-tested.
258 - if variables or arguments "disappear" (become undef) or become
259 corrupted please contact the author so he cen iron out the
260 remaining bugs.
261 - this module is not thread-safe. You must only ever use this module from 295 - this module is not thread-safe. You must only ever use this module from
262 the same thread (this requirement might be loosened in the future to 296 the same thread (this requirement might be loosened in the future to
263 allow per-thread schedulers, but Coro::State does not yet allow this). 297 allow per-thread schedulers, but Coro::State does not yet allow this).
264 298
265=head1 SEE ALSO 299=head1 SEE ALSO
266 300
267L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 301L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
268L<Coro::Signal>, L<Coro::State>, L<Coro::Event>. 302L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>,
303L<Coro::Handle>, L<Coro::Socket>.
269 304
270=head1 AUTHOR 305=head1 AUTHOR
271 306
272 Marc Lehmann <pcg@goof.com> 307 Marc Lehmann <pcg@goof.com>
273 http://www.goof.com/pcg/marc/ 308 http://www.goof.com/pcg/marc/

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