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Revision 1.37 by root, Mon Sep 24 02:25:44 2001 UTC vs.
Revision 1.90 by root, Thu Nov 30 18:21:14 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
176Calling C<exit> in a coroutine will not work correctly, so do not do that.
177
178When the coroutine dies, the program will exit, just as in the main
179program.
146 180
147 # create a new coroutine that just prints its arguments 181 # create a new coroutine that just prints its arguments
148 async { 182 async {
149 print "@_\n"; 183 print "@_\n";
150 } 1,2,3,4; 184 } 1,2,3,4;
151 185
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 186=cut
156 187
157sub async(&@) { 188sub async(&@) {
158 my $pid = new Coro @_; 189 my $pid = new Coro @_;
159 $manager->ready; # this ensures that the stack is cloned from the manager
160 $pid->ready; 190 $pid->ready;
161 $pid; 191 $pid
162} 192}
163 193
164=item schedule 194=item schedule
165 195
166Calls the scheduler. Please note that the current process will not be put 196Calls 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 205ready queue and calls C<schedule>, which has the effect of giving up the
176current "timeslice" to other coroutines of the same or higher priority. 206current "timeslice" to other coroutines of the same or higher priority.
177 207
178=cut 208=cut
179 209
180=item terminate 210=item terminate [arg...]
181 211
182Terminates the current process. 212Terminates the current process with the given status values (see L<cancel>).
183
184Future versions of this function will allow result arguments.
185 213
186=cut 214=cut
187 215
188sub terminate { 216sub terminate {
189 $current->cancel; 217 $current->cancel (@_);
190 &schedule;
191 die; # NORETURN
192} 218}
193 219
194=back 220=back
195 221
196# dynamic methods 222# dynamic methods
202=over 4 228=over 4
203 229
204=item new Coro \&sub [, @args...] 230=item new Coro \&sub [, @args...]
205 231
206Create a new process and return it. When the sub returns the process 232Create a new process and return it. When the sub returns the process
207automatically terminates. To start the process you must first put it into 233automatically terminates as if C<terminate> with the returned values were
234called. To make the process run you must first put it into the ready queue
208the ready queue by calling the ready method. 235by calling the ready method.
209 236
210The coderef you submit MUST NOT be a closure that refers to variables 237Calling C<exit> in a coroutine will not work correctly, so do not do that.
211in an outer scope. This does NOT work. Pass arguments into it instead.
212 238
213=cut 239=cut
214 240
215sub _newcoro { 241sub _new_coro {
216 terminate &{+shift}; 242 terminate &{+shift};
217} 243}
218 244
219sub new { 245sub new {
220 my $class = shift; 246 my $class = shift;
221 bless {
222 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
223 }, $class;
224}
225 247
248 $class->SUPER::new (\&_new_coro, @_)
249}
250
226=item $process->ready 251=item $success = $process->ready
227 252
228Put the current process into the ready queue. 253Put the given process into the ready queue (according to it's priority)
254and return true. If the process is already in the ready queue, do nothing
255and return false.
229 256
230=cut 257=item $is_ready = $process->is_ready
231 258
259Return wether the process is currently the ready queue or not,
260
232=item $process->cancel 261=item $process->cancel (arg...)
233 262
234Like C<terminate>, but terminates the specified process instead. 263Terminates the given process and makes it return the given arguments as
264status (default: the empty list).
235 265
236=cut 266=cut
237 267
238sub cancel { 268sub cancel {
269 my $self = shift;
270 $self->{status} = [@_];
239 push @destroy, $_[0]; 271 push @destroy, $self;
240 $manager->ready; 272 $manager->ready;
241 &schedule if $current == $_[0]; 273 &schedule if $current == $self;
242} 274}
243 275
276=item $process->join
277
278Wait until the coroutine terminates and return any values given to the
279C<terminate> or C<cancel> functions. C<join> can be called multiple times
280from multiple processes.
281
282=cut
283
284sub join {
285 my $self = shift;
286 unless ($self->{status}) {
287 push @{$self->{join}}, $current;
288 &schedule;
289 }
290 wantarray ? @{$self->{status}} : $self->{status}[0];
291}
292
244=item $oldprio = $process->prio($newprio) 293=item $oldprio = $process->prio ($newprio)
245 294
246Sets the priority of the process. Higher priority processes get run before 295Sets (or gets, if the argument is missing) the priority of the
296process. Higher priority processes get run before lower priority
247lower priority processes. Priorities are smalled signed integer (currently 297processes. Priorities are small signed integers (currently -4 .. +3),
248-4 .. +3), that you can refer to using PRIO_xxx constants (use the import 298that you can refer to using PRIO_xxx constants (use the import tag :prio
249tag :prio to get then): 299to get then):
250 300
251 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 301 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
252 3 > 1 > 0 > -1 > -3 > -4 302 3 > 1 > 0 > -1 > -3 > -4
253 303
254 # set priority to HIGH 304 # set priority to HIGH
260Changing the priority of the current process will take effect immediately, 310Changing the priority of the current process will take effect immediately,
261but changing the priority of processes in the ready queue (but not 311but changing the priority of processes in the ready queue (but not
262running) will only take effect after the next schedule (of that 312running) will only take effect after the next schedule (of that
263process). This is a bug that will be fixed in some future version. 313process). This is a bug that will be fixed in some future version.
264 314
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) 315=item $newprio = $process->nice ($change)
274 316
275Similar to C<prio>, but subtract the given value from the priority (i.e. 317Similar to C<prio>, but subtract the given value from the priority (i.e.
276higher values mean lower priority, just as in unix). 318higher values mean lower priority, just as in unix).
277 319
278=cut 320=item $olddesc = $process->desc ($newdesc)
279 321
280sub nice { 322Sets (or gets in case the argument is missing) the description for this
281 $_[0]{prio} -= $_[1]; 323process. This is just a free-form string you can associate with a process.
324
325=cut
326
327sub desc {
328 my $old = $_[0]{desc};
329 $_[0]{desc} = $_[1] if @_ > 1;
330 $old;
282} 331}
283 332
284=back 333=back
285 334
286=cut 335=cut
287 336
2881; 3371;
289 338
290=head1 BUGS/LIMITATIONS 339=head1 BUGS/LIMITATIONS
291 340
292 - you must make very sure that no coro is still active on global destruction. 341 - you must make very sure that no coro is still active on global
293 very bad things might happen otherwise (usually segfaults). 342 destruction. very bad things might happen otherwise (usually segfaults).
343
294 - this module is not thread-safe. You must only ever use this module from 344 - 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 345 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). 346 to allow per-thread schedulers, but Coro::State does not yet allow
347 this).
297 348
298=head1 SEE ALSO 349=head1 SEE ALSO
299 350
300L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, 351Support/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>, 352
302L<Coro::Handle>, L<Coro::Socket>. 353Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
354
355Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
356
357Embedding: L<Coro:MakeMaker>
303 358
304=head1 AUTHOR 359=head1 AUTHOR
305 360
306 Marc Lehmann <pcg@goof.com> 361 Marc Lehmann <schmorp@schmorp.de>
307 http://www.goof.com/pcg/marc/ 362 http://home.schmorp.de/
308 363
309=cut 364=cut
310 365

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