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Revision 1.37 by root, Mon Sep 24 02:25:44 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+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own
30callchain, it's own set of lexicals and it's own set of perl's most 28callchain, it's own set of lexicals and it's own set of perl's most
31important global variables. 29important global variables.
32 30
33=cut 31=cut
34 32
35package Coro; 33package Coro;
36 34
35use strict;
37no warnings qw(uninitialized); 36no warnings "uninitialized";
38 37
39use Coro::State; 38use Coro::State;
40 39
41use base Exporter; 40use base qw(Coro::State Exporter);
42 41
43$VERSION = 0.5; 42our $idle; # idle handler
43our $main; # main coroutine
44our $current; # current coroutine
44 45
46our $VERSION = '3.0';
47
45@EXPORT = qw(async cede schedule terminate current); 48our @EXPORT = qw(async cede schedule terminate current);
46%EXPORT_TAGS = ( 49our %EXPORT_TAGS = (
47 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 50 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
48); 51);
49@EXPORT_OK = @{$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 = new Coro sub { 138my $manager; $manager = new Coro sub {
122 while() { 139 while () {
123 # by overwriting the state object with the manager we destroy it 140 # by overwriting the state object with the manager we destroy it
124 # while still being able to schedule this coroutine (in case it has 141 # while still being able to schedule this coroutine (in case it has
125 # been readied multiple times. this is harmless since the manager 142 # been readied multiple times. this is harmless since the manager
126 # can be called as many times as neccessary and will always 143 # can be called as many times as neccessary and will always
127 # remove itself from the runqueue 144 # remove itself from the runqueue
128 (pop @destroy)->{_coro_state} = $manager->{_coro_state} while @destroy; 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 }
129 &schedule; 156 &schedule;
130 } 157 }
131}; 158};
132 159
133# static methods. not really. 160# static methods. not really.
134 161
162=back
163
135=head2 STATIC METHODS 164=head2 STATIC METHODS
136 165
137Static methods are actually functions that operate on the current process only. 166Static methods are actually functions that operate on the current process only.
138 167
139=over 4 168=over 4
141=item async { ... } [@args...] 170=item async { ... } [@args...]
142 171
143Create a new asynchronous process and return it's process object 172Create a new asynchronous process and return it's process object
144(usually unused). When the sub returns the new process is automatically 173(usually unused). When the sub returns the new process is automatically
145terminated. 174terminated.
175
176When the coroutine dies, the program will exit, just as in the main
177program.
146 178
147 # create a new coroutine that just prints its arguments 179 # create a new coroutine that just prints its arguments
148 async { 180 async {
149 print "@_\n"; 181 print "@_\n";
150 } 1,2,3,4; 182 } 1,2,3,4;
151 183
152The coderef you submit MUST NOT be a closure that refers to variables
153in an outer scope. This does NOT work. Pass arguments into it instead.
154
155=cut 184=cut
156 185
157sub async(&@) { 186sub async(&@) {
158 my $pid = new Coro @_; 187 my $pid = new Coro @_;
159 $manager->ready; # this ensures that the stack is cloned from the manager
160 $pid->ready; 188 $pid->ready;
161 $pid; 189 $pid
162} 190}
163 191
164=item schedule 192=item schedule
165 193
166Calls 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
175ready 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
176current "timeslice" to other coroutines of the same or higher priority. 204current "timeslice" to other coroutines of the same or higher priority.
177 205
178=cut 206=cut
179 207
180=item terminate 208=item terminate [arg...]
181 209
182Terminates the current process. 210Terminates the current process with the given status values (see L<cancel>).
183
184Future versions of this function will allow result arguments.
185 211
186=cut 212=cut
187 213
188sub terminate { 214sub terminate {
189 $current->cancel; 215 $current->cancel (@_);
190 &schedule;
191 die; # NORETURN
192} 216}
193 217
194=back 218=back
195 219
196# dynamic methods 220# dynamic methods
202=over 4 226=over 4
203 227
204=item new Coro \&sub [, @args...] 228=item new Coro \&sub [, @args...]
205 229
206Create 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
207automatically 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
208the ready queue by calling the ready method. 233by calling the ready method.
209 234
210The coderef you submit MUST NOT be a closure that refers to variables
211in an outer scope. This does NOT work. Pass arguments into it instead.
212
213=cut 235=cut
214 236
215sub _newcoro { 237sub _new_coro {
216 terminate &{+shift}; 238 terminate &{+shift};
217} 239}
218 240
219sub new { 241sub new {
220 my $class = shift; 242 my $class = shift;
221 bless { 243
222 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 244 $class->SUPER::new (\&_new_coro, @_)
223 }, $class;
224} 245}
225 246
226=item $process->ready 247=item $process->ready
227 248
228Put the current process into the ready queue. 249Put the given process into the ready queue.
229 250
230=cut 251=cut
231 252
232=item $process->cancel 253=item $process->cancel (arg...)
233 254
234Like 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).
235 257
236=cut 258=cut
237 259
238sub cancel { 260sub cancel {
261 my $self = shift;
262 $self->{status} = [@_];
239 push @destroy, $_[0]; 263 push @destroy, $self;
240 $manager->ready; 264 $manager->ready;
241 &schedule if $current == $_[0]; 265 &schedule if $current == $self;
242} 266}
243 267
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
244=item $oldprio = $process->prio($newprio) 285=item $oldprio = $process->prio ($newprio)
245 286
246Sets 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
247lower priority processes. Priorities are smalled signed integer (currently 289processes. Priorities are small signed integers (currently -4 .. +3),
248-4 .. +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
249tag :prio to get then): 291to get then):
250 292
251 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
252 3 > 1 > 0 > -1 > -3 > -4 294 3 > 1 > 0 > -1 > -3 > -4
253 295
254 # set priority to HIGH 296 # set priority to HIGH
260Changing the priority of the current process will take effect immediately, 302Changing the priority of the current process will take effect immediately,
261but changing the priority of processes in the ready queue (but not 303but changing the priority of processes in the ready queue (but not
262running) will only take effect after the next schedule (of that 304running) will only take effect after the next schedule (of that
263process). 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.
264 306
265=cut
266
267sub prio {
268 my $old = $_[0]{prio};
269 $_[0]{prio} = $_[1] if @_ > 1;
270 $old;
271}
272
273=item $newprio = $process->nice($change) 307=item $newprio = $process->nice ($change)
274 308
275Similar 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.
276higher values mean lower priority, just as in unix). 310higher values mean lower priority, just as in unix).
277 311
278=cut 312=item $olddesc = $process->desc ($newdesc)
279 313
280sub nice { 314Sets (or gets in case the argument is missing) the description for this
281 $_[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;
282} 323}
283 324
284=back 325=back
285 326
286=cut 327=cut
287 328
2881; 3291;
289 330
290=head1 BUGS/LIMITATIONS 331=head1 BUGS/LIMITATIONS
291 332
292 - 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
293 very bad things might happen otherwise (usually segfaults). 334 destruction. very bad things might happen otherwise (usually segfaults).
335
294 - 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
295 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
296 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).
297 340
298=head1 SEE ALSO 341=head1 SEE ALSO
299 342
300L<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>.
301L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 344
302L<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>
303 350
304=head1 AUTHOR 351=head1 AUTHOR
305 352
306 Marc Lehmann <pcg@goof.com> 353 Marc Lehmann <schmorp@schmorp.de>
307 http://www.goof.com/pcg/marc/ 354 http://home.schmorp.de/
308 355
309=cut 356=cut
310 357

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