… | |
… | |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
9 | async { |
9 | async { |
10 | # some asynchronous thread of execution |
10 | # some asynchronous thread of execution |
|
|
11 | print "2\n"; |
|
|
12 | cede; # yield back to main |
|
|
13 | print "4\n"; |
11 | }; |
14 | }; |
|
|
15 | print "1\n"; |
|
|
16 | cede; # yield to coroutine |
|
|
17 | print "3\n"; |
|
|
18 | cede; # and again |
12 | |
19 | |
13 | # alternatively create an async process like this: |
20 | # use locking |
|
|
21 | my $lock = new Coro::Semaphore; |
|
|
22 | my $locked; |
14 | |
23 | |
15 | sub some_func : Coro { |
24 | $lock->down; |
16 | # some more async code |
25 | $locked = 1; |
17 | } |
26 | $lock->up; |
18 | |
|
|
19 | cede; |
|
|
20 | |
27 | |
21 | =head1 DESCRIPTION |
28 | =head1 DESCRIPTION |
22 | |
29 | |
23 | This module collection manages coroutines. Coroutines are similar to |
30 | This module collection manages coroutines. Coroutines are similar |
24 | Threads but don't run in parallel. |
31 | to threads but don't run in parallel at the same time even on SMP |
|
|
32 | machines. The specific flavor of coroutine used in this module also |
|
|
33 | guarantees you that it will not switch between coroutines unless |
|
|
34 | necessary, at easily-identified points in your program, so locking and |
|
|
35 | parallel access are rarely an issue, making coroutine programming much |
|
|
36 | safer than threads programming. |
25 | |
37 | |
26 | This module is still experimental, see the BUGS section below. |
38 | (Perl, however, does not natively support real threads but instead does a |
|
|
39 | very slow and memory-intensive emulation of processes using threads. This |
|
|
40 | is a performance win on Windows machines, and a loss everywhere else). |
27 | |
41 | |
28 | In this module, coroutines are defined as "callchain + lexical variables |
42 | In this module, coroutines are defined as "callchain + lexical variables + |
29 | + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own |
43 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
30 | callchain, it's own set of lexicals and it's own set of perl's most |
44 | its own set of lexicals and its own set of perls most important global |
31 | important global variables. |
45 | variables (see L<Coro::State> for more configuration). |
32 | |
46 | |
33 | =cut |
47 | =cut |
34 | |
48 | |
35 | package Coro; |
49 | package Coro; |
36 | |
50 | |
|
|
51 | use strict; |
|
|
52 | no warnings "uninitialized"; |
|
|
53 | |
37 | use Coro::State; |
54 | use Coro::State; |
38 | |
55 | |
39 | use base Exporter; |
56 | use base qw(Coro::State Exporter); |
40 | |
57 | |
41 | $VERSION = 0.49; |
58 | our $idle; # idle handler |
|
|
59 | our $main; # main coroutine |
|
|
60 | our $current; # current coroutine |
42 | |
61 | |
|
|
62 | our $VERSION = '4.51'; |
|
|
63 | |
43 | @EXPORT = qw(async cede schedule terminate current); |
64 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
44 | %EXPORT_TAGS = ( |
65 | our %EXPORT_TAGS = ( |
45 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
66 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
46 | ); |
67 | ); |
47 | @EXPORT_OK = @{$EXPORT_TAGS{prio}}; |
68 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
48 | |
69 | |
49 | { |
70 | { |
50 | my @async; |
71 | my @async; |
51 | my $init; |
72 | my $init; |
52 | |
73 | |
53 | # this way of handling attributes simply is NOT scalable ;() |
74 | # this way of handling attributes simply is NOT scalable ;() |
54 | sub import { |
75 | sub import { |
|
|
76 | no strict 'refs'; |
|
|
77 | |
55 | Coro->export_to_level(1, @_); |
78 | Coro->export_to_level (1, @_); |
|
|
79 | |
56 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
80 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
57 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
81 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
58 | my ($package, $ref) = (shift, shift); |
82 | my ($package, $ref) = (shift, shift); |
59 | my @attrs; |
83 | my @attrs; |
60 | for (@_) { |
84 | for (@_) { |
… | |
… | |
75 | }; |
99 | }; |
76 | } |
100 | } |
77 | |
101 | |
78 | } |
102 | } |
79 | |
103 | |
|
|
104 | =over 4 |
|
|
105 | |
80 | =item $main |
106 | =item $main |
81 | |
107 | |
82 | This coroutine represents the main program. |
108 | This coroutine represents the main program. |
83 | |
109 | |
84 | =cut |
110 | =cut |
85 | |
111 | |
86 | our $main = new Coro; |
112 | $main = new Coro; |
87 | |
113 | |
88 | =item $current (or as function: current) |
114 | =item $current (or as function: current) |
89 | |
115 | |
90 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
116 | The current coroutine (the last coroutine switched to). The initial value |
|
|
117 | is C<$main> (of course). |
91 | |
118 | |
|
|
119 | This variable is B<strictly> I<read-only>. It is provided for performance |
|
|
120 | reasons. If performance is not essential you are encouraged to use the |
|
|
121 | C<Coro::current> function instead. |
|
|
122 | |
92 | =cut |
123 | =cut |
|
|
124 | |
|
|
125 | $main->{desc} = "[main::]"; |
93 | |
126 | |
94 | # maybe some other module used Coro::Specific before... |
127 | # maybe some other module used Coro::Specific before... |
95 | if ($current) { |
|
|
96 | $main->{specific} = $current->{specific}; |
128 | $main->{_specific} = $current->{_specific} |
97 | } |
129 | if $current; |
98 | |
130 | |
99 | our $current = $main; |
131 | _set_current $main; |
100 | |
132 | |
101 | sub current() { $current } |
133 | sub current() { $current } |
102 | |
134 | |
103 | =item $idle |
135 | =item $idle |
104 | |
136 | |
105 | The coroutine to switch to when no other coroutine is running. The default |
137 | A callback that is called whenever the scheduler finds no ready coroutines |
106 | implementation prints "FATAL: deadlock detected" and exits. |
138 | to run. The default implementation prints "FATAL: deadlock detected" and |
|
|
139 | exits, because the program has no other way to continue. |
107 | |
140 | |
108 | =cut |
141 | This hook is overwritten by modules such as C<Coro::Timer> and |
|
|
142 | C<Coro::Event> to wait on an external event that hopefully wake up a |
|
|
143 | coroutine so the scheduler can run it. |
109 | |
144 | |
110 | # should be done using priorities :( |
145 | Please note that if your callback recursively invokes perl (e.g. for event |
111 | our $idle = new Coro sub { |
146 | handlers), then it must be prepared to be called recursively itself. |
112 | print STDERR "FATAL: deadlock detected\n"; |
147 | |
113 | exit(51); |
148 | =cut |
|
|
149 | |
|
|
150 | $idle = sub { |
|
|
151 | require Carp; |
|
|
152 | Carp::croak ("FATAL: deadlock detected"); |
114 | }; |
153 | }; |
|
|
154 | |
|
|
155 | sub _cancel { |
|
|
156 | my ($self) = @_; |
|
|
157 | |
|
|
158 | # free coroutine data and mark as destructed |
|
|
159 | $self->_destroy |
|
|
160 | or return; |
|
|
161 | |
|
|
162 | # call all destruction callbacks |
|
|
163 | $_->(@{$self->{_status}}) |
|
|
164 | for @{(delete $self->{_on_destroy}) || []}; |
|
|
165 | } |
115 | |
166 | |
116 | # this coroutine is necessary because a coroutine |
167 | # this coroutine is necessary because a coroutine |
117 | # cannot destroy itself. |
168 | # cannot destroy itself. |
118 | my @destroy; |
169 | my @destroy; |
|
|
170 | my $manager; |
|
|
171 | |
119 | my $manager = new Coro sub { |
172 | $manager = new Coro sub { |
120 | while() { |
173 | while () { |
121 | delete ((pop @destroy)->{_coro_state}) while @destroy; |
174 | (shift @destroy)->_cancel |
|
|
175 | while @destroy; |
|
|
176 | |
122 | &schedule; |
177 | &schedule; |
123 | } |
178 | } |
124 | }; |
179 | }; |
|
|
180 | $manager->desc ("[coro manager]"); |
|
|
181 | $manager->prio (PRIO_MAX); |
125 | |
182 | |
126 | # static methods. not really. |
183 | # static methods. not really. |
127 | |
184 | |
|
|
185 | =back |
|
|
186 | |
128 | =head2 STATIC METHODS |
187 | =head2 STATIC METHODS |
129 | |
188 | |
130 | Static methods are actually functions that operate on the current process only. |
189 | Static methods are actually functions that operate on the current coroutine only. |
131 | |
190 | |
132 | =over 4 |
191 | =over 4 |
133 | |
192 | |
134 | =item async { ... } [@args...] |
193 | =item async { ... } [@args...] |
135 | |
194 | |
136 | Create a new asynchronous process and return it's process object |
195 | Create a new asynchronous coroutine and return it's coroutine object |
137 | (usually unused). When the sub returns the new process is automatically |
196 | (usually unused). When the sub returns the new coroutine is automatically |
138 | terminated. |
197 | terminated. |
|
|
198 | |
|
|
199 | See the C<Coro::State::new> constructor for info about the coroutine |
|
|
200 | environment in which coroutines run. |
|
|
201 | |
|
|
202 | Calling C<exit> in a coroutine will do the same as calling exit outside |
|
|
203 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
|
|
204 | just as it would in the main program. |
139 | |
205 | |
140 | # create a new coroutine that just prints its arguments |
206 | # create a new coroutine that just prints its arguments |
141 | async { |
207 | async { |
142 | print "@_\n"; |
208 | print "@_\n"; |
143 | } 1,2,3,4; |
209 | } 1,2,3,4; |
144 | |
210 | |
145 | The coderef you submit MUST NOT be a closure that refers to variables |
|
|
146 | in an outer scope. This does NOT work. Pass arguments into it instead. |
|
|
147 | |
|
|
148 | =cut |
211 | =cut |
149 | |
212 | |
150 | sub async(&@) { |
213 | sub async(&@) { |
151 | my $pid = new Coro @_; |
214 | my $coro = new Coro @_; |
152 | $manager->ready; # this ensures that the stack is cloned from the manager |
|
|
153 | $pid->ready; |
215 | $coro->ready; |
154 | $pid; |
216 | $coro |
|
|
217 | } |
|
|
218 | |
|
|
219 | =item async_pool { ... } [@args...] |
|
|
220 | |
|
|
221 | Similar to C<async>, but uses a coroutine pool, so you should not call |
|
|
222 | terminate or join (although you are allowed to), and you get a coroutine |
|
|
223 | that might have executed other code already (which can be good or bad :). |
|
|
224 | |
|
|
225 | Also, the block is executed in an C<eval> context and a warning will be |
|
|
226 | issued in case of an exception instead of terminating the program, as |
|
|
227 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
|
|
228 | will not work in the expected way, unless you call terminate or cancel, |
|
|
229 | which somehow defeats the purpose of pooling. |
|
|
230 | |
|
|
231 | The priority will be reset to C<0> after each job, tracing will be |
|
|
232 | disabled, the description will be reset and the default output filehandle |
|
|
233 | gets restored, so you can change alkl these. Otherwise the coroutine will |
|
|
234 | be re-used "as-is": most notably if you change other per-coroutine global |
|
|
235 | stuff such as C<$/> you need to revert that change, which is most simply |
|
|
236 | done by using local as in C< local $/ >. |
|
|
237 | |
|
|
238 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
|
|
239 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
|
|
240 | required. |
|
|
241 | |
|
|
242 | If you are concerned about pooled coroutines growing a lot because a |
|
|
243 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
|
|
244 | { terminate }> once per second or so to slowly replenish the pool. In |
|
|
245 | addition to that, when the stacks used by a handler grows larger than 16kb |
|
|
246 | (adjustable with $Coro::POOL_RSS) it will also exit. |
|
|
247 | |
|
|
248 | =cut |
|
|
249 | |
|
|
250 | our $POOL_SIZE = 8; |
|
|
251 | our $POOL_RSS = 16 * 1024; |
|
|
252 | our @async_pool; |
|
|
253 | |
|
|
254 | sub pool_handler { |
|
|
255 | my $cb; |
|
|
256 | |
|
|
257 | while () { |
|
|
258 | eval { |
|
|
259 | while () { |
|
|
260 | _pool_1 $cb; |
|
|
261 | &$cb; |
|
|
262 | _pool_2 $cb; |
|
|
263 | &schedule; |
|
|
264 | } |
|
|
265 | }; |
|
|
266 | |
|
|
267 | last if $@ eq "\3async_pool terminate\2\n"; |
|
|
268 | warn $@ if $@; |
|
|
269 | } |
|
|
270 | } |
|
|
271 | |
|
|
272 | sub async_pool(&@) { |
|
|
273 | # this is also inlined into the unlock_scheduler |
|
|
274 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
275 | |
|
|
276 | $coro->{_invoke} = [@_]; |
|
|
277 | $coro->ready; |
|
|
278 | |
|
|
279 | $coro |
155 | } |
280 | } |
156 | |
281 | |
157 | =item schedule |
282 | =item schedule |
158 | |
283 | |
159 | Calls the scheduler. Please note that the current process will not be put |
284 | Calls the scheduler. Please note that the current coroutine will not be put |
160 | into the ready queue, so calling this function usually means you will |
285 | into the ready queue, so calling this function usually means you will |
161 | never be called again. |
286 | never be called again unless something else (e.g. an event handler) calls |
|
|
287 | ready. |
162 | |
288 | |
163 | =cut |
289 | The canonical way to wait on external events is this: |
|
|
290 | |
|
|
291 | { |
|
|
292 | # remember current coroutine |
|
|
293 | my $current = $Coro::current; |
|
|
294 | |
|
|
295 | # register a hypothetical event handler |
|
|
296 | on_event_invoke sub { |
|
|
297 | # wake up sleeping coroutine |
|
|
298 | $current->ready; |
|
|
299 | undef $current; |
|
|
300 | }; |
|
|
301 | |
|
|
302 | # call schedule until event occurred. |
|
|
303 | # in case we are woken up for other reasons |
|
|
304 | # (current still defined), loop. |
|
|
305 | Coro::schedule while $current; |
|
|
306 | } |
164 | |
307 | |
165 | =item cede |
308 | =item cede |
166 | |
309 | |
167 | "Cede" to other processes. This function puts the current process into the |
310 | "Cede" to other coroutines. This function puts the current coroutine into the |
168 | ready queue and calls C<schedule>, which has the effect of giving up the |
311 | ready queue and calls C<schedule>, which has the effect of giving up the |
169 | current "timeslice" to other coroutines of the same or higher priority. |
312 | current "timeslice" to other coroutines of the same or higher priority. |
170 | |
313 | |
171 | =cut |
314 | =item Coro::cede_notself |
172 | |
315 | |
|
|
316 | Works like cede, but is not exported by default and will cede to any |
|
|
317 | coroutine, regardless of priority, once. |
|
|
318 | |
173 | =item terminate |
319 | =item terminate [arg...] |
174 | |
320 | |
175 | Terminates the current process. |
321 | Terminates the current coroutine with the given status values (see L<cancel>). |
176 | |
322 | |
177 | Future versions of this function will allow result arguments. |
323 | =item killall |
|
|
324 | |
|
|
325 | Kills/terminates/cancels all coroutines except the currently running |
|
|
326 | one. This is useful after a fork, either in the child or the parent, as |
|
|
327 | usually only one of them should inherit the running coroutines. |
178 | |
328 | |
179 | =cut |
329 | =cut |
180 | |
330 | |
181 | sub terminate { |
331 | sub terminate { |
182 | $current->cancel; |
332 | $current->cancel (@_); |
183 | &schedule; |
333 | } |
184 | die; # NORETURN |
334 | |
|
|
335 | sub killall { |
|
|
336 | for (Coro::State::list) { |
|
|
337 | $_->cancel |
|
|
338 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
|
|
339 | } |
185 | } |
340 | } |
186 | |
341 | |
187 | =back |
342 | =back |
188 | |
343 | |
189 | # dynamic methods |
344 | # dynamic methods |
190 | |
345 | |
191 | =head2 PROCESS METHODS |
346 | =head2 COROUTINE METHODS |
192 | |
347 | |
193 | These are the methods you can call on process objects. |
348 | These are the methods you can call on coroutine objects. |
194 | |
349 | |
195 | =over 4 |
350 | =over 4 |
196 | |
351 | |
197 | =item new Coro \&sub [, @args...] |
352 | =item new Coro \&sub [, @args...] |
198 | |
353 | |
199 | Create a new process and return it. When the sub returns the process |
354 | Create a new coroutine and return it. When the sub returns the coroutine |
200 | automatically terminates. To start the process you must first put it into |
355 | automatically terminates as if C<terminate> with the returned values were |
|
|
356 | called. To make the coroutine run you must first put it into the ready queue |
201 | the ready queue by calling the ready method. |
357 | by calling the ready method. |
202 | |
358 | |
203 | The coderef you submit MUST NOT be a closure that refers to variables |
359 | See C<async> and C<Coro::State::new> for additional info about the |
204 | in an outer scope. This does NOT work. Pass arguments into it instead. |
360 | coroutine environment. |
205 | |
361 | |
206 | =cut |
362 | =cut |
207 | |
363 | |
208 | sub _newcoro { |
364 | sub _run_coro { |
209 | terminate &{+shift}; |
365 | terminate &{+shift}; |
210 | } |
366 | } |
211 | |
367 | |
212 | sub new { |
368 | sub new { |
213 | my $class = shift; |
369 | my $class = shift; |
214 | bless { |
|
|
215 | _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), |
|
|
216 | }, $class; |
|
|
217 | } |
|
|
218 | |
370 | |
219 | =item $process->ready |
371 | $class->SUPER::new (\&_run_coro, @_) |
|
|
372 | } |
220 | |
373 | |
221 | Put the current process into the ready queue. |
374 | =item $success = $coroutine->ready |
222 | |
375 | |
223 | =cut |
376 | Put the given coroutine into the ready queue (according to it's priority) |
|
|
377 | and return true. If the coroutine is already in the ready queue, do nothing |
|
|
378 | and return false. |
224 | |
379 | |
225 | =item $process->cancel |
380 | =item $is_ready = $coroutine->is_ready |
226 | |
381 | |
227 | Like C<terminate>, but terminates the specified process instead. |
382 | Return wether the coroutine is currently the ready queue or not, |
|
|
383 | |
|
|
384 | =item $coroutine->cancel (arg...) |
|
|
385 | |
|
|
386 | Terminates the given coroutine and makes it return the given arguments as |
|
|
387 | status (default: the empty list). Never returns if the coroutine is the |
|
|
388 | current coroutine. |
228 | |
389 | |
229 | =cut |
390 | =cut |
230 | |
391 | |
231 | sub cancel { |
392 | sub cancel { |
|
|
393 | my $self = shift; |
|
|
394 | $self->{_status} = [@_]; |
|
|
395 | |
|
|
396 | if ($current == $self) { |
232 | push @destroy, $_[0]; |
397 | push @destroy, $self; |
233 | $manager->ready; |
398 | $manager->ready; |
|
|
399 | &schedule while 1; |
|
|
400 | } else { |
|
|
401 | $self->_cancel; |
|
|
402 | } |
234 | } |
403 | } |
235 | |
404 | |
|
|
405 | =item $coroutine->join |
|
|
406 | |
|
|
407 | Wait until the coroutine terminates and return any values given to the |
|
|
408 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
|
|
409 | from multiple coroutines. |
|
|
410 | |
|
|
411 | =cut |
|
|
412 | |
|
|
413 | sub join { |
|
|
414 | my $self = shift; |
|
|
415 | |
|
|
416 | unless ($self->{_status}) { |
|
|
417 | my $current = $current; |
|
|
418 | |
|
|
419 | push @{$self->{_on_destroy}}, sub { |
|
|
420 | $current->ready; |
|
|
421 | undef $current; |
|
|
422 | }; |
|
|
423 | |
|
|
424 | &schedule while $current; |
|
|
425 | } |
|
|
426 | |
|
|
427 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
|
|
428 | } |
|
|
429 | |
|
|
430 | =item $coroutine->on_destroy (\&cb) |
|
|
431 | |
|
|
432 | Registers a callback that is called when this coroutine gets destroyed, |
|
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433 | but before it is joined. The callback gets passed the terminate arguments, |
|
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434 | if any. |
|
|
435 | |
|
|
436 | =cut |
|
|
437 | |
|
|
438 | sub on_destroy { |
|
|
439 | my ($self, $cb) = @_; |
|
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440 | |
|
|
441 | push @{ $self->{_on_destroy} }, $cb; |
|
|
442 | } |
|
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443 | |
236 | =item $oldprio = $process->prio($newprio) |
444 | =item $oldprio = $coroutine->prio ($newprio) |
237 | |
445 | |
238 | Sets the priority of the process. Higher priority processes get run before |
446 | Sets (or gets, if the argument is missing) the priority of the |
239 | lower priority processes. Priorities are smalled signed integer (currently |
447 | coroutine. Higher priority coroutines get run before lower priority |
|
|
448 | coroutines. Priorities are small signed integers (currently -4 .. +3), |
240 | -4 .. +3), that you can refer to using PRIO_xxx constants (use the import |
449 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
241 | tag :prio to get then): |
450 | to get then): |
242 | |
451 | |
243 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
452 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
244 | 3 > 1 > 0 > -1 > -3 > -4 |
453 | 3 > 1 > 0 > -1 > -3 > -4 |
245 | |
454 | |
246 | # set priority to HIGH |
455 | # set priority to HIGH |
247 | current->prio(PRIO_HIGH); |
456 | current->prio(PRIO_HIGH); |
248 | |
457 | |
249 | The idle coroutine ($Coro::idle) always has a lower priority than any |
458 | The idle coroutine ($Coro::idle) always has a lower priority than any |
250 | existing coroutine. |
459 | existing coroutine. |
251 | |
460 | |
252 | Changing the priority of the current process will take effect immediately, |
461 | Changing the priority of the current coroutine will take effect immediately, |
253 | but changing the priority of processes in the ready queue (but not |
462 | but changing the priority of coroutines in the ready queue (but not |
254 | running) will only take effect after the next schedule (of that |
463 | running) will only take effect after the next schedule (of that |
255 | process). This is a bug that will be fixed in some future version. |
464 | coroutine). This is a bug that will be fixed in some future version. |
256 | |
465 | |
257 | =cut |
|
|
258 | |
|
|
259 | sub prio { |
|
|
260 | my $old = $_[0]{prio}; |
|
|
261 | $_[0]{prio} = $_[1] if @_ > 1; |
|
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262 | $old; |
|
|
263 | } |
|
|
264 | |
|
|
265 | =item $newprio = $process->nice($change) |
466 | =item $newprio = $coroutine->nice ($change) |
266 | |
467 | |
267 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
468 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
268 | higher values mean lower priority, just as in unix). |
469 | higher values mean lower priority, just as in unix). |
269 | |
470 | |
270 | =cut |
471 | =item $olddesc = $coroutine->desc ($newdesc) |
271 | |
472 | |
272 | sub nice { |
473 | Sets (or gets in case the argument is missing) the description for this |
273 | $_[0]{prio} -= $_[1]; |
474 | coroutine. This is just a free-form string you can associate with a coroutine. |
|
|
475 | |
|
|
476 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
|
|
477 | can modify this member directly if you wish. |
|
|
478 | |
|
|
479 | =item $coroutine->throw ([$scalar]) |
|
|
480 | |
|
|
481 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
482 | inside the coroutine at the next convinient point in time (usually after |
|
|
483 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
484 | exception object. |
|
|
485 | |
|
|
486 | The exception object will be thrown "as is" with the specified scalar in |
|
|
487 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
488 | (unlike with C<die>). |
|
|
489 | |
|
|
490 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
491 | end itself, although there is no guarentee that the exception will lead to |
|
|
492 | termination, and if the exception isn't caught it might well end the whole |
|
|
493 | program. |
|
|
494 | |
|
|
495 | =cut |
|
|
496 | |
|
|
497 | sub desc { |
|
|
498 | my $old = $_[0]{desc}; |
|
|
499 | $_[0]{desc} = $_[1] if @_ > 1; |
|
|
500 | $old; |
274 | } |
501 | } |
275 | |
502 | |
276 | =back |
503 | =back |
277 | |
504 | |
|
|
505 | =head2 GLOBAL FUNCTIONS |
|
|
506 | |
|
|
507 | =over 4 |
|
|
508 | |
|
|
509 | =item Coro::nready |
|
|
510 | |
|
|
511 | Returns the number of coroutines that are currently in the ready state, |
|
|
512 | i.e. that can be switched to. The value C<0> means that the only runnable |
|
|
513 | coroutine is the currently running one, so C<cede> would have no effect, |
|
|
514 | and C<schedule> would cause a deadlock unless there is an idle handler |
|
|
515 | that wakes up some coroutines. |
|
|
516 | |
|
|
517 | =item my $guard = Coro::guard { ... } |
|
|
518 | |
|
|
519 | This creates and returns a guard object. Nothing happens until the object |
|
|
520 | gets destroyed, in which case the codeblock given as argument will be |
|
|
521 | executed. This is useful to free locks or other resources in case of a |
|
|
522 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
523 | guard block will be executed. The guard object supports only one method, |
|
|
524 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
|
525 | |
|
|
526 | Example: set some flag and clear it again when the coroutine gets canceled |
|
|
527 | or the function returns: |
|
|
528 | |
|
|
529 | sub do_something { |
|
|
530 | my $guard = Coro::guard { $busy = 0 }; |
|
|
531 | $busy = 1; |
|
|
532 | |
|
|
533 | # do something that requires $busy to be true |
|
|
534 | } |
|
|
535 | |
|
|
536 | =cut |
|
|
537 | |
|
|
538 | sub guard(&) { |
|
|
539 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
540 | } |
|
|
541 | |
|
|
542 | sub Coro::guard::cancel { |
|
|
543 | ${$_[0]} = sub { }; |
|
|
544 | } |
|
|
545 | |
|
|
546 | sub Coro::guard::DESTROY { |
|
|
547 | ${$_[0]}->(); |
|
|
548 | } |
|
|
549 | |
|
|
550 | |
|
|
551 | =item unblock_sub { ... } |
|
|
552 | |
|
|
553 | This utility function takes a BLOCK or code reference and "unblocks" it, |
|
|
554 | returning the new coderef. This means that the new coderef will return |
|
|
555 | immediately without blocking, returning nothing, while the original code |
|
|
556 | ref will be called (with parameters) from within its own coroutine. |
|
|
557 | |
|
|
558 | The reason this function exists is that many event libraries (such as the |
|
|
559 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
|
|
560 | of thread-safety). This means you must not block within event callbacks, |
|
|
561 | otherwise you might suffer from crashes or worse. |
|
|
562 | |
|
|
563 | This function allows your callbacks to block by executing them in another |
|
|
564 | coroutine where it is safe to block. One example where blocking is handy |
|
|
565 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
|
|
566 | disk. |
|
|
567 | |
|
|
568 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
|
|
569 | creating event callbacks that want to block. |
|
|
570 | |
|
|
571 | =cut |
|
|
572 | |
|
|
573 | our @unblock_queue; |
|
|
574 | |
|
|
575 | # we create a special coro because we want to cede, |
|
|
576 | # to reduce pressure on the coro pool (because most callbacks |
|
|
577 | # return immediately and can be reused) and because we cannot cede |
|
|
578 | # inside an event callback. |
|
|
579 | our $unblock_scheduler = new Coro sub { |
|
|
580 | while () { |
|
|
581 | while (my $cb = pop @unblock_queue) { |
|
|
582 | # this is an inlined copy of async_pool |
|
|
583 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
584 | |
|
|
585 | $coro->{_invoke} = $cb; |
|
|
586 | $coro->ready; |
|
|
587 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
588 | } |
|
|
589 | schedule; # sleep well |
|
|
590 | } |
|
|
591 | }; |
|
|
592 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
|
|
593 | |
|
|
594 | sub unblock_sub(&) { |
|
|
595 | my $cb = shift; |
|
|
596 | |
|
|
597 | sub { |
|
|
598 | unshift @unblock_queue, [$cb, @_]; |
|
|
599 | $unblock_scheduler->ready; |
|
|
600 | } |
|
|
601 | } |
|
|
602 | |
|
|
603 | =back |
|
|
604 | |
278 | =cut |
605 | =cut |
279 | |
606 | |
280 | 1; |
607 | 1; |
281 | |
608 | |
282 | =head1 BUGS/LIMITATIONS |
609 | =head1 BUGS/LIMITATIONS |
283 | |
610 | |
284 | - could be faster, especially when the core would introduce special |
611 | - you must make very sure that no coro is still active on global |
285 | support for coroutines (like it does for threads). |
612 | destruction. very bad things might happen otherwise (usually segfaults). |
286 | - there is still a memleak on coroutine termination that I could not |
613 | |
287 | identify. Could be as small as a single SV. |
|
|
288 | - this module is not well-tested. |
|
|
289 | - if variables or arguments "disappear" (become undef) or become |
|
|
290 | corrupted please contact the author so he cen iron out the |
|
|
291 | remaining bugs. |
|
|
292 | - this module is not thread-safe. You must only ever use this module from |
614 | - this module is not thread-safe. You should only ever use this module |
293 | the same thread (this requirement might be loosened in the future to |
615 | from the same thread (this requirement might be loosened in the future |
294 | allow per-thread schedulers, but Coro::State does not yet allow this). |
616 | to allow per-thread schedulers, but Coro::State does not yet allow |
|
|
617 | this). |
295 | |
618 | |
296 | =head1 SEE ALSO |
619 | =head1 SEE ALSO |
297 | |
620 | |
298 | L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
621 | Lower level Configuration, Coroutine Environment: L<Coro::State>. |
299 | L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, |
622 | |
300 | L<Coro::Handle>, L<Coro::Socket>. |
623 | Debugging: L<Coro::Debug>. |
|
|
624 | |
|
|
625 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
|
|
626 | |
|
|
627 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
|
|
628 | |
|
|
629 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>. |
|
|
630 | |
|
|
631 | Compatibility: L<Coro::LWP>, L<Coro::Storable>, L<Coro::Select>. |
|
|
632 | |
|
|
633 | Embedding: L<Coro::MakeMaker>. |
301 | |
634 | |
302 | =head1 AUTHOR |
635 | =head1 AUTHOR |
303 | |
636 | |
304 | Marc Lehmann <pcg@goof.com> |
637 | Marc Lehmann <schmorp@schmorp.de> |
305 | http://www.goof.com/pcg/marc/ |
638 | http://home.schmorp.de/ |
306 | |
639 | |
307 | =cut |
640 | =cut |
308 | |
641 | |