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Revision 1.41 by root, Tue Nov 6 20:34:09 2001 UTC vs.
Revision 1.83 by root, Fri Nov 24 15:34:33 2006 UTC

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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;
37no warnings qw(uninitialized); 36no warnings "uninitialized";
38 37
39use Coro::State; 38use Coro::State;
40 39
41use base Exporter; 40use base qw(Coro::State Exporter);
42 41
42our $idle; # idle handler
43our $main; # main coroutine
44our $current; # current coroutine
45
43$VERSION = 0.52; 46our $VERSION = '2.5';
44 47
45@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
46%EXPORT_TAGS = ( 49our %EXPORT_TAGS = (
47 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48); 51);
49@EXPORT_OK = @{$EXPORT_TAGS{prio}}; 52our @EXPORT_OK = @{$EXPORT_TAGS{prio}};
50 53
51{ 54{
52 my @async; 55 my @async;
53 my $init; 56 my $init;
54 57
55 # this way of handling attributes simply is NOT scalable ;() 58 # this way of handling attributes simply is NOT scalable ;()
56 sub import { 59 sub import {
60 no strict 'refs';
61
57 Coro->export_to_level(1, @_); 62 Coro->export_to_level(1, @_);
63
58 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; 64 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
59 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { 65 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
60 my ($package, $ref) = (shift, shift); 66 my ($package, $ref) = (shift, shift);
61 my @attrs; 67 my @attrs;
62 for (@_) { 68 for (@_) {
… …
77 }; 83 };
78 } 84 }
79 85
80} 86}
81 87
88=over 4
89
82=item $main 90=item $main
83 91
84This coroutine represents the main program. 92This coroutine represents the main program.
85 93
86=cut 94=cut
87 95
88our $main = new Coro; 96$main = new Coro;
89 97
90=item $current (or as function: current) 98=item $current (or as function: current)
91 99
92The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). 100The current coroutine (the last coroutine switched to). The initial value
101is C<$main> (of course).
102
103This variable is B<strictly> I<read-only>. It is provided for performance
104reasons. If performance is not essentiel you are encouraged to use the
105C<Coro::current> function instead.
93 106
94=cut 107=cut
95 108
96# maybe some other module used Coro::Specific before... 109# maybe some other module used Coro::Specific before...
97if ($current) { 110if ($current) {
98 $main->{specific} = $current->{specific}; 111 $main->{specific} = $current->{specific};
99} 112}
100 113
101our $current = $main; 114$current = $main;
102 115
103sub current() { $current } 116sub current() { $current }
104 117
105=item $idle 118=item $idle
106 119
107The coroutine to switch to when no other coroutine is running. The default 120A callback that is called whenever the scheduler finds no ready coroutines
108implementation prints "FATAL: deadlock detected" and exits. 121to run. The default implementation prints "FATAL: deadlock detected" and
122exits.
109 123
110=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.
111 127
112# should be done using priorities :( 128=cut
113our $idle = new Coro sub { 129
130$idle = sub {
114 print STDERR "FATAL: deadlock detected\n"; 131 print STDERR "FATAL: deadlock detected\n";
115 exit(51); 132 exit (51);
116}; 133};
117 134
118# this coroutine is necessary because a coroutine 135# this coroutine is necessary because a coroutine
119# cannot destroy itself. 136# cannot destroy itself.
120my @destroy; 137my @destroy;
121my $manager; 138my $manager;
122$manager = new Coro sub { 139$manager = new Coro sub {
123 while() { 140 while () {
124 # by overwriting the state object with the manager we destroy it 141 # by overwriting the state object with the manager we destroy it
125 # while still being able to schedule this coroutine (in case it has 142 # while still being able to schedule this coroutine (in case it has
126 # been readied multiple times. this is harmless since the manager 143 # been readied multiple times. this is harmless since the manager
127 # can be called as many times as neccessary and will always 144 # can be called as many times as neccessary and will always
128 # remove itself from the runqueue 145 # remove itself from the runqueue
129 while (@destroy) { 146 while (@destroy) {
130 my $coro = pop @destroy; 147 my $coro = pop @destroy;
131 $coro->{status} ||= []; 148 $coro->{status} ||= [];
132 $_->ready for @{delete $coro->{join} || []}; 149 $_->ready for @{delete $coro->{join} || []};
133 $coro->{_coro_state} = $manager->{_coro_state}; 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);
134 } 156 }
135 &schedule; 157 &schedule;
136 } 158 }
137}; 159};
138 160
139# static methods. not really. 161# static methods. not really.
140 162
163=back
164
141=head2 STATIC METHODS 165=head2 STATIC METHODS
142 166
143Static methods are actually functions that operate on the current process only. 167Static methods are actually functions that operate on the current process only.
144 168
145=over 4 169=over 4
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147=item async { ... } [@args...] 171=item async { ... } [@args...]
148 172
149Create a new asynchronous process and return it's process object 173Create a new asynchronous process and return it's process object
150(usually unused). When the sub returns the new process is automatically 174(usually unused). When the sub returns the new process is automatically
151terminated. 175terminated.
176
177When the coroutine dies, the program will exit, just as in the main
178program.
152 179
153 # create a new coroutine that just prints its arguments 180 # create a new coroutine that just prints its arguments
154 async { 181 async {
155 print "@_\n"; 182 print "@_\n";
156 } 1,2,3,4; 183 } 1,2,3,4;
157
158The coderef you submit MUST NOT be a closure that refers to variables
159in an outer scope. This does NOT work. Pass arguments into it instead.
160 184
161=cut 185=cut
162 186
163sub async(&@) { 187sub async(&@) {
164 my $pid = new Coro @_; 188 my $pid = new Coro @_;
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183 207
184=cut 208=cut
185 209
186=item terminate [arg...] 210=item terminate [arg...]
187 211
188Terminates the current process. 212Terminates the current process with the given status values (see L<cancel>).
189
190Future versions of this function will allow result arguments.
191 213
192=cut 214=cut
193 215
194sub terminate { 216sub terminate {
195 $current->{status} = [@_];
196 $current->cancel; 217 $current->cancel (@_);
197 &schedule;
198 die; # NORETURN
199} 218}
200 219
201=back 220=back
202 221
203# dynamic methods 222# dynamic methods
… …
221 terminate &{+shift}; 240 terminate &{+shift};
222} 241}
223 242
224sub new { 243sub new {
225 my $class = shift; 244 my $class = shift;
226 bless { 245
227 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 246 $class->SUPER::new (\&_newcoro, @_)
228 }, $class;
229} 247}
230 248
231=item $process->ready 249=item $process->ready
232 250
233Put the given process into the ready queue. 251Put the given process into the ready queue.
234 252
235=cut 253=cut
236 254
237=item $process->cancel 255=item $process->cancel (arg...)
238 256
239Like 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).
240 259
241=cut 260=cut
242 261
243sub cancel { 262sub cancel {
263 my $self = shift;
264 $self->{status} = [@_];
244 push @destroy, $_[0]; 265 push @destroy, $self;
245 $manager->ready; 266 $manager->ready;
246 &schedule if $current == $_[0]; 267 &schedule if $current == $self;
247} 268}
248 269
249=item $process->join 270=item $process->join
250 271
251Wait until the coroutine terminates and return any values given to the 272Wait until the coroutine terminates and return any values given to the
252C<terminate> function. C<join> can be called multiple times from multiple 273C<terminate> or C<cancel> functions. C<join> can be called multiple times
253processes. 274from multiple processes.
254 275
255=cut 276=cut
256 277
257sub join { 278sub join {
258 my $self = shift; 279 my $self = shift;
… …
261 &schedule; 282 &schedule;
262 } 283 }
263 wantarray ? @{$self->{status}} : $self->{status}[0]; 284 wantarray ? @{$self->{status}} : $self->{status}[0];
264} 285}
265 286
266=item $oldprio = $process->prio($newprio) 287=item $oldprio = $process->prio ($newprio)
267 288
268Sets (or gets, if the argument is missing) the priority of the 289Sets (or gets, if the argument is missing) the priority of the
269process. Higher priority processes get run before lower priority 290process. Higher priority processes get run before lower priority
270processes. Priorities are smalled signed integer (currently -4 .. +3), 291processes. Priorities are small signed integers (currently -4 .. +3),
271that you can refer to using PRIO_xxx constants (use the import tag :prio 292that you can refer to using PRIO_xxx constants (use the import tag :prio
272to get then): 293to get then):
273 294
274 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
275 3 > 1 > 0 > -1 > -3 > -4 296 3 > 1 > 0 > -1 > -3 > -4
… …
283Changing the priority of the current process will take effect immediately, 304Changing the priority of the current process will take effect immediately,
284but changing the priority of processes in the ready queue (but not 305but changing the priority of processes in the ready queue (but not
285running) will only take effect after the next schedule (of that 306running) will only take effect after the next schedule (of that
286process). 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.
287 308
288=cut
289
290sub prio {
291 my $old = $_[0]{prio};
292 $_[0]{prio} = $_[1] if @_ > 1;
293 $old;
294}
295
296=item $newprio = $process->nice($change) 309=item $newprio = $process->nice ($change)
297 310
298Similar 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.
299higher values mean lower priority, just as in unix). 312higher values mean lower priority, just as in unix).
300 313
301=cut
302
303sub nice {
304 $_[0]{prio} -= $_[1];
305}
306
307=item $olddesc = $process->desc($newdesc) 314=item $olddesc = $process->desc ($newdesc)
308 315
309Sets (or gets in case the argument is missing) the description for this 316Sets (or gets in case the argument is missing) the description for this
310process. This is just a free-form string you can associate with a process. 317process. This is just a free-form string you can associate with a process.
311 318
312=cut 319=cut
… …
323 330
3241; 3311;
325 332
326=head1 BUGS/LIMITATIONS 333=head1 BUGS/LIMITATIONS
327 334
328 - 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
329 very bad things might happen otherwise (usually segfaults). 336 destruction. very bad things might happen otherwise (usually segfaults).
337
330 - 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
331 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
332 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).
333 342
334=head1 SEE ALSO 343=head1 SEE ALSO
335 344
336L<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>.
337L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 346
338L<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>
339 352
340=head1 AUTHOR 353=head1 AUTHOR
341 354
342 Marc Lehmann <pcg@goof.com> 355 Marc Lehmann <schmorp@schmorp.de>
343 http://www.goof.com/pcg/marc/ 356 http://home.schmorp.de/
344 357
345=cut 358=cut
346 359

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