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Revision 1.25 by root, Wed Jul 25 21:12:57 2001 UTC vs.
Revision 1.61 by pcg, Fri May 14 13:25:08 2004 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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") }
36
37use Coro::State; 37use Coro::State;
38 38
39use vars qw($idle $main $current);
40
39use base Exporter; 41use base Exporter;
40 42
41$VERSION = 0.12; 43$VERSION = 0.97;
42 44
43@EXPORT = qw(async cede schedule terminate current); 45@EXPORT = qw(async cede schedule terminate current);
44@EXPORT_OK = qw($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}};
45 50
46{ 51{
47 my @async; 52 my @async;
53 my $init;
48 54
49 # this way of handling attributes simply is NOT scalable ;() 55 # this way of handling attributes simply is NOT scalable ;()
50 sub import { 56 sub import {
51 Coro->export_to_level(1, @_); 57 Coro->export_to_level(1, @_);
52 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 58 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
… …
54 my ($package, $ref) = (shift, shift); 60 my ($package, $ref) = (shift, shift);
55 my @attrs; 61 my @attrs;
56 for (@_) { 62 for (@_) {
57 if ($_ eq "Coro") { 63 if ($_ eq "Coro") {
58 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 }
59 } else { 72 } else {
60 push @attrs, $_; 73 push @attrs, $_;
61 } 74 }
62 } 75 }
63 return $old ? $old->($package, $ref, @attrs) : @attrs; 76 return $old ? $old->($package, $ref, @attrs) : @attrs;
64 }; 77 };
65 } 78 }
66 79
67 sub INIT {
68 &async(pop @async) while @async;
69 }
70} 80}
81
82=over 4
71 83
72=item $main 84=item $main
73 85
74This coroutine represents the main program. 86This coroutine represents the main program.
75 87
76=cut 88=cut
77 89
78our $main = new Coro; 90$main = new Coro;
79 91
80=item $current (or as function: current) 92=item $current (or as function: current)
81 93
82The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 94The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
83 95
… …
86# maybe some other module used Coro::Specific before... 98# maybe some other module used Coro::Specific before...
87if ($current) { 99if ($current) {
88 $main->{specific} = $current->{specific}; 100 $main->{specific} = $current->{specific};
89} 101}
90 102
91our $current = $main; 103$current = $main;
92 104
93sub current() { $current } 105sub current() { $current }
94 106
95=item $idle 107=item $idle
96 108
… …
98implementation prints "FATAL: deadlock detected" and exits. 110implementation prints "FATAL: deadlock detected" and exits.
99 111
100=cut 112=cut
101 113
102# should be done using priorities :( 114# should be done using priorities :(
103our $idle = new Coro sub { 115$idle = new Coro sub {
104 print STDERR "FATAL: deadlock detected\n"; 116 print STDERR "FATAL: deadlock detected\n";
105 exit(51); 117 exit(51);
106}; 118};
107 119
108# this coroutine is necessary because a coroutine 120# this coroutine is necessary because a coroutine
109# cannot destroy itself. 121# cannot destroy itself.
110my @destroy; 122my @destroy;
123my $manager;
111my $manager = new Coro sub { 124$manager = new Coro sub {
112 while() { 125 while () {
113 delete ((pop @destroy)->{_coro_state}) while @destroy; 126 # by overwriting the state object with the manager we destroy it
127 # while still being able to schedule this coroutine (in case it has
128 # been readied multiple times. this is harmless since the manager
129 # can be called as many times as neccessary and will always
130 # remove itself from the runqueue
131 while (@destroy) {
132 my $coro = pop @destroy;
133 $coro->{status} ||= [];
134 $_->ready for @{delete $coro->{join} || []};
135
136 # the next line destroys the _coro_state, but keeps the
137 # process itself intact (we basically make it a zombie
138 # process that always runs the manager thread, so it's possible
139 # to transfer() to this process).
140 $coro->{_coro_state} = $manager->{_coro_state};
141 }
114 &schedule; 142 &schedule;
115 } 143 }
116}; 144};
117 145
118# we really need priorities...
119my @ready; # the ready queue. hehe, rather broken ;)
120
121# static methods. not really. 146# static methods. not really.
147
148=back
122 149
123=head2 STATIC METHODS 150=head2 STATIC METHODS
124 151
125Static methods are actually functions that operate on the current process only. 152Static methods are actually functions that operate on the current process only.
126 153
… …
134 161
135 # create a new coroutine that just prints its arguments 162 # create a new coroutine that just prints its arguments
136 async { 163 async {
137 print "@_\n"; 164 print "@_\n";
138 } 1,2,3,4; 165 } 1,2,3,4;
139
140The coderef you submit MUST NOT be a closure that refers to variables
141in an outer scope. This does NOT work. Pass arguments into it instead.
142 166
143=cut 167=cut
144 168
145sub async(&@) { 169sub async(&@) {
146 my $pid = new Coro @_; 170 my $pid = new Coro @_;
… …
155into the ready queue, so calling this function usually means you will 179into the ready queue, so calling this function usually means you will
156never be called again. 180never be called again.
157 181
158=cut 182=cut
159 183
160my $prev;
161
162sub schedule {
163 # should be done using priorities :(
164 ($prev, $current) = ($current, shift @ready || $idle);
165 Coro::State::transfer($prev, $current);
166}
167
168=item cede 184=item cede
169 185
170"Cede" to other processes. This function puts the current process into the 186"Cede" to other processes. This function puts the current process into the
171ready queue and calls C<schedule>, which has the effect of giving up the 187ready queue and calls C<schedule>, which has the effect of giving up the
172current "timeslice" to other coroutines of the same or higher priority. 188current "timeslice" to other coroutines of the same or higher priority.
173 189
174=cut 190=cut
175 191
176sub cede {
177 $current->ready;
178 &schedule;
179}
180
181=item terminate 192=item terminate [arg...]
182 193
183Terminates the current process. 194Terminates the current process with the given status values (see L<cancel>).
184
185Future versions of this function will allow result arguments.
186 195
187=cut 196=cut
188 197
189sub terminate { 198sub terminate {
190 push @destroy, $current; 199 $current->cancel (@_);
191 $manager->ready;
192 &schedule;
193 # NORETURN
194} 200}
195 201
196=back 202=back
197 203
198# dynamic methods 204# dynamic methods
… …
204=over 4 210=over 4
205 211
206=item new Coro \&sub [, @args...] 212=item new Coro \&sub [, @args...]
207 213
208Create a new process and return it. When the sub returns the process 214Create a new process and return it. When the sub returns the process
209automatically terminates. To start the process you must first put it into 215automatically terminates as if C<terminate> with the returned values were
216called. To make the process run you must first put it into the ready queue
210the ready queue by calling the ready method. 217by calling the ready method.
211
212The coderef you submit MUST NOT be a closure that refers to variables
213in an outer scope. This does NOT work. Pass arguments into it instead.
214 218
215=cut 219=cut
216 220
217sub _newcoro { 221sub _newcoro {
218 terminate &{+shift}; 222 terminate &{+shift};
… …
225 }, $class; 229 }, $class;
226} 230}
227 231
228=item $process->ready 232=item $process->ready
229 233
230Put the current process into the ready queue. 234Put the given process into the ready queue.
231 235
232=cut 236=cut
233 237
234sub ready { 238=item $process->cancel (arg...)
235 push @ready, $_[0]; 239
240Temrinates the given process and makes it return the given arguments as
241status (default: the empty list).
242
243=cut
244
245sub cancel {
246 my $self = shift;
247 $self->{status} = [@_];
248 push @destroy, $self;
249 $manager->ready;
250 &schedule if $current == $self;
251}
252
253=item $process->join
254
255Wait until the coroutine terminates and return any values given to the
256C<terminate> or C<cancel> functions. C<join> can be called multiple times
257from multiple processes.
258
259=cut
260
261sub join {
262 my $self = shift;
263 unless ($self->{status}) {
264 push @{$self->{join}}, $current;
265 &schedule;
266 }
267 wantarray ? @{$self->{status}} : $self->{status}[0];
268}
269
270=item $oldprio = $process->prio($newprio)
271
272Sets (or gets, if the argument is missing) the priority of the
273process. Higher priority processes get run before lower priority
274processes. Priorities are small signed integers (currently -4 .. +3),
275that you can refer to using PRIO_xxx constants (use the import tag :prio
276to get then):
277
278 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
279 3 > 1 > 0 > -1 > -3 > -4
280
281 # set priority to HIGH
282 current->prio(PRIO_HIGH);
283
284The idle coroutine ($Coro::idle) always has a lower priority than any
285existing coroutine.
286
287Changing the priority of the current process will take effect immediately,
288but changing the priority of processes in the ready queue (but not
289running) will only take effect after the next schedule (of that
290process). This is a bug that will be fixed in some future version.
291
292=cut
293
294sub prio {
295 my $old = $_[0]{prio};
296 $_[0]{prio} = $_[1] if @_ > 1;
297 $old;
298}
299
300=item $newprio = $process->nice($change)
301
302Similar to C<prio>, but subtract the given value from the priority (i.e.
303higher values mean lower priority, just as in unix).
304
305=cut
306
307sub nice {
308 $_[0]{prio} -= $_[1];
309}
310
311=item $olddesc = $process->desc($newdesc)
312
313Sets (or gets in case the argument is missing) the description for this
314process. This is just a free-form string you can associate with a process.
315
316=cut
317
318sub desc {
319 my $old = $_[0]{desc};
320 $_[0]{desc} = $_[1] if @_ > 1;
321 $old;
236} 322}
237 323
238=back 324=back
239 325
240=cut 326=cut
241 327
2421; 3281;
243 329
244=head1 BUGS/LIMITATIONS 330=head1 BUGS/LIMITATIONS
245 331
246 - could be faster, especially when the core would introduce special 332 - you must make very sure that no coro is still active on global
247 support for coroutines (like it does for threads). 333 destruction. very bad things might happen otherwise (usually segfaults).
248 - there is still a memleak on coroutine termination that I could not 334
249 identify. Could be as small as a single SV.
250 - this module is not well-tested.
251 - if variables or arguments "disappear" (become undef) or become
252 corrupted please contact the author so he cen iron out the
253 remaining bugs.
254 - this module is not thread-safe. You must only ever use this module from 335 - this module is not thread-safe. You should only ever use this module
255 the same thread (this requirement might be loosened in the future to 336 from the same thread (this requirement might be losened in the future
256 allow per-thread schedulers, but Coro::State does not yet allow this). 337 to allow per-thread schedulers, but Coro::State does not yet allow
338 this).
257 339
258=head1 SEE ALSO 340=head1 SEE ALSO
259 341
260L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 342L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
261L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 343L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>,
262L<Coro::L<Coro::Handle>, L<Coro::Socket>. 344L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>.
263 345
264=head1 AUTHOR 346=head1 AUTHOR
265 347
266 Marc Lehmann <pcg@goof.com> 348 Marc Lehmann <pcg@goof.com>
267 http://www.goof.com/pcg/marc/ 349 http://www.goof.com/pcg/marc/

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