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Revision 1.38 by root, Wed Oct 3 01:09:56 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 = 0.51; 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 $manager;
122$manager = new Coro sub { 138my $manager; $manager = new Coro sub {
123 while() { 139 while () {
124 # by overwriting the state object with the manager we destroy it 140 # by overwriting the state object with the manager we destroy it
125 # 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
126 # been readied multiple times. this is harmless since the manager 142 # been readied multiple times. this is harmless since the manager
127 # can be called as many times as neccessary and will always 143 # can be called as many times as neccessary and will always
128 # remove itself from the runqueue 144 # remove itself from the runqueue
129 (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 }
130 &schedule; 156 &schedule;
131 } 157 }
132}; 158};
133 159
134# static methods. not really. 160# static methods. not really.
135 161
162=back
163
136=head2 STATIC METHODS 164=head2 STATIC METHODS
137 165
138Static methods are actually functions that operate on the current process only. 166Static methods are actually functions that operate on the current process only.
139 167
140=over 4 168=over 4
142=item async { ... } [@args...] 170=item async { ... } [@args...]
143 171
144Create a new asynchronous process and return it's process object 172Create a new asynchronous process and return it's process object
145(usually unused). When the sub returns the new process is automatically 173(usually unused). When the sub returns the new process is automatically
146terminated. 174terminated.
175
176When the coroutine dies, the program will exit, just as in the main
177program.
147 178
148 # create a new coroutine that just prints its arguments 179 # create a new coroutine that just prints its arguments
149 async { 180 async {
150 print "@_\n"; 181 print "@_\n";
151 } 1,2,3,4; 182 } 1,2,3,4;
152 183
153The coderef you submit MUST NOT be a closure that refers to variables
154in an outer scope. This does NOT work. Pass arguments into it instead.
155
156=cut 184=cut
157 185
158sub async(&@) { 186sub async(&@) {
159 my $pid = new Coro @_; 187 my $pid = new Coro @_;
160 $manager->ready; # this ensures that the stack is cloned from the manager
161 $pid->ready; 188 $pid->ready;
162 $pid; 189 $pid
163} 190}
164 191
165=item schedule 192=item schedule
166 193
167Calls 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
176ready 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
177current "timeslice" to other coroutines of the same or higher priority. 204current "timeslice" to other coroutines of the same or higher priority.
178 205
179=cut 206=cut
180 207
181=item terminate 208=item terminate [arg...]
182 209
183Terminates the current process. 210Terminates the current process with the given status values (see L<cancel>).
184
185Future versions of this function will allow result arguments.
186 211
187=cut 212=cut
188 213
189sub terminate { 214sub terminate {
190 $current->cancel; 215 $current->cancel (@_);
191 &schedule;
192 die; # NORETURN
193} 216}
194 217
195=back 218=back
196 219
197# dynamic methods 220# dynamic methods
203=over 4 226=over 4
204 227
205=item new Coro \&sub [, @args...] 228=item new Coro \&sub [, @args...]
206 229
207Create 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
208automatically 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
209the ready queue by calling the ready method. 233by calling the ready method.
210 234
211The coderef you submit MUST NOT be a closure that refers to variables
212in an outer scope. This does NOT work. Pass arguments into it instead.
213
214=cut 235=cut
215 236
216sub _newcoro { 237sub _new_coro {
217 terminate &{+shift}; 238 terminate &{+shift};
218} 239}
219 240
220sub new { 241sub new {
221 my $class = shift; 242 my $class = shift;
222 bless { 243
223 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), 244 $class->SUPER::new (\&_new_coro, @_)
224 }, $class;
225} 245}
226 246
227=item $process->ready 247=item $process->ready
228 248
229Put the current process into the ready queue. 249Put the given process into the ready queue.
230 250
231=cut 251=cut
232 252
233=item $process->cancel 253=item $process->cancel (arg...)
234 254
235Like 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).
236 257
237=cut 258=cut
238 259
239sub cancel { 260sub cancel {
261 my $self = shift;
262 $self->{status} = [@_];
240 push @destroy, $_[0]; 263 push @destroy, $self;
241 $manager->ready; 264 $manager->ready;
242 &schedule if $current == $_[0]; 265 &schedule if $current == $self;
243} 266}
244 267
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
245=item $oldprio = $process->prio($newprio) 285=item $oldprio = $process->prio ($newprio)
246 286
247Sets 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
248lower priority processes. Priorities are smalled signed integer (currently 289processes. Priorities are small signed integers (currently -4 .. +3),
249-4 .. +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
250tag :prio to get then): 291to get then):
251 292
252 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
253 3 > 1 > 0 > -1 > -3 > -4 294 3 > 1 > 0 > -1 > -3 > -4
254 295
255 # set priority to HIGH 296 # set priority to HIGH
261Changing the priority of the current process will take effect immediately, 302Changing the priority of the current process will take effect immediately,
262but changing the priority of processes in the ready queue (but not 303but changing the priority of processes in the ready queue (but not
263running) will only take effect after the next schedule (of that 304running) will only take effect after the next schedule (of that
264process). 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.
265 306
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) 307=item $newprio = $process->nice ($change)
275 308
276Similar 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.
277higher values mean lower priority, just as in unix). 310higher values mean lower priority, just as in unix).
278 311
279=cut 312=item $olddesc = $process->desc ($newdesc)
280 313
281sub nice { 314Sets (or gets in case the argument is missing) the description for this
282 $_[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;
283} 323}
284 324
285=back 325=back
286 326
287=cut 327=cut
288 328
2891; 3291;
290 330
291=head1 BUGS/LIMITATIONS 331=head1 BUGS/LIMITATIONS
292 332
293 - 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
294 very bad things might happen otherwise (usually segfaults). 334 destruction. very bad things might happen otherwise (usually segfaults).
335
295 - 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
296 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
297 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).
298 340
299=head1 SEE ALSO 341=head1 SEE ALSO
300 342
301L<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>.
302L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, 344
303L<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>
304 350
305=head1 AUTHOR 351=head1 AUTHOR
306 352
307 Marc Lehmann <pcg@goof.com> 353 Marc Lehmann <schmorp@schmorp.de>
308 http://www.goof.com/pcg/marc/ 354 http://home.schmorp.de/
309 355
310=cut 356=cut
311 357

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