… | |
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2 | |
2 | |
3 | Coro - coroutine process abstraction |
3 | Coro - coroutine process abstraction |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
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"; |
11 | print "2\n"; |
12 | cede; # yield back to main |
12 | cede; # yield back to main |
13 | print "4\n"; |
13 | print "4\n"; |
14 | }; |
14 | }; |
15 | print "1\n"; |
15 | print "1\n"; |
16 | cede; # yield to coroutine |
16 | cede; # yield to coroutine |
17 | print "3\n"; |
17 | print "3\n"; |
18 | cede; # and again |
18 | cede; # and again |
19 | |
19 | |
20 | # use locking |
20 | # use locking |
21 | my $lock = new Coro::Semaphore; |
21 | my $lock = new Coro::Semaphore; |
22 | my $locked; |
22 | my $locked; |
23 | |
23 | |
24 | $lock->down; |
24 | $lock->down; |
25 | $locked = 1; |
25 | $locked = 1; |
26 | $lock->up; |
26 | $lock->up; |
27 | |
27 | |
28 | =head1 DESCRIPTION |
28 | =head1 DESCRIPTION |
29 | |
29 | |
30 | This module collection manages coroutines. Coroutines are similar |
30 | This module collection manages coroutines. Coroutines are similar to |
31 | to threads but don't run in parallel at the same time even on SMP |
31 | threads but don't (in general) run in parallel at the same time even |
32 | machines. The specific flavor of coroutine used in this module also |
32 | on SMP machines. The specific flavor of coroutine used in this module |
33 | guarantees you that it will not switch between coroutines unless |
33 | also guarantees you that it will not switch between coroutines unless |
34 | necessary, at easily-identified points in your program, so locking and |
34 | necessary, at easily-identified points in your program, so locking and |
35 | parallel access are rarely an issue, making coroutine programming much |
35 | parallel access are rarely an issue, making coroutine programming much |
36 | safer than threads programming. |
36 | safer and easier than threads programming. |
37 | |
37 | |
38 | (Perl, however, does not natively support real threads but instead does a |
38 | Unlike a normal perl program, however, coroutines allow you to have |
39 | very slow and memory-intensive emulation of processes using threads. This |
39 | multiple running interpreters that share data, which is especially useful |
40 | is a performance win on Windows machines, and a loss everywhere else). |
40 | to code pseudo-parallel processes, such as multiple HTTP-GET requests |
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41 | running concurrently. |
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42 | |
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43 | Coroutines are also useful because Perl has no support for threads (the so |
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44 | called "threads" that perl offers are nothing more than the (bad) process |
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45 | emulation coming from the Windows platform: On standard operating systems |
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46 | they serve no purpose whatsoever, except by making your programs slow and |
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47 | making them use a lot of memory. Best disable them when building perl, or |
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48 | aks your software vendor/distributor to do it for you). |
41 | |
49 | |
42 | In this module, coroutines are defined as "callchain + lexical variables + |
50 | In this module, coroutines are defined as "callchain + lexical variables + |
43 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
51 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
44 | its own set of lexicals and its own set of perls most important global |
52 | its own set of lexicals and its own set of perls most important global |
45 | variables (see L<Coro::State> for more configuration). |
53 | variables (see L<Coro::State> for more configuration). |
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57 | |
65 | |
58 | our $idle; # idle handler |
66 | our $idle; # idle handler |
59 | our $main; # main coroutine |
67 | our $main; # main coroutine |
60 | our $current; # current coroutine |
68 | our $current; # current coroutine |
61 | |
69 | |
62 | our $VERSION = '4.32'; |
70 | our $VERSION = 4.6; |
63 | |
71 | |
64 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
72 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
65 | our %EXPORT_TAGS = ( |
73 | our %EXPORT_TAGS = ( |
66 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
74 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
67 | ); |
75 | ); |
68 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
76 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
69 | |
77 | |
70 | { |
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71 | my @async; |
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72 | my $init; |
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73 | |
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74 | # this way of handling attributes simply is NOT scalable ;() |
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75 | sub import { |
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76 | no strict 'refs'; |
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77 | |
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78 | Coro->export_to_level (1, @_); |
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79 | |
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80 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
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81 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
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82 | my ($package, $ref) = (shift, shift); |
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83 | my @attrs; |
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84 | for (@_) { |
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85 | if ($_ eq "Coro") { |
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86 | push @async, $ref; |
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87 | unless ($init++) { |
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88 | eval q{ |
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89 | sub INIT { |
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90 | &async(pop @async) while @async; |
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91 | } |
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92 | }; |
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93 | } |
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94 | } else { |
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95 | push @attrs, $_; |
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96 | } |
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97 | } |
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98 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
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99 | }; |
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100 | } |
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101 | |
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102 | } |
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103 | |
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104 | =over 4 |
78 | =over 4 |
105 | |
79 | |
106 | =item $main |
80 | =item $Coro::main |
107 | |
81 | |
108 | This coroutine represents the main program. |
82 | This variable stores the coroutine object that represents the main |
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83 | program. While you cna C<ready> it and do most other things you can do to |
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84 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
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85 | wether you are running in the main program or not. |
109 | |
86 | |
110 | =cut |
87 | =cut |
111 | |
88 | |
112 | $main = new Coro; |
89 | $main = new Coro; |
113 | |
90 | |
114 | =item $current (or as function: current) |
91 | =item $Coro::current |
115 | |
92 | |
116 | The current coroutine (the last coroutine switched to). The initial value |
93 | The coroutine object representing the current coroutine (the last |
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94 | coroutine that the Coro scheduler switched to). The initial value is |
117 | is C<$main> (of course). |
95 | C<$main> (of course). |
118 | |
96 | |
119 | This variable is B<strictly> I<read-only>. It is provided for performance |
97 | This variable is B<strictly> I<read-only>. You can take copies of the |
120 | reasons. If performance is not essential you are encouraged to use the |
98 | value stored in it and use it as any other coroutine object, but you must |
121 | C<Coro::current> function instead. |
99 | not otherwise modify the variable itself. |
122 | |
100 | |
123 | =cut |
101 | =cut |
124 | |
102 | |
125 | $main->{desc} = "[main::]"; |
103 | $main->{desc} = "[main::]"; |
126 | |
104 | |
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128 | $main->{_specific} = $current->{_specific} |
106 | $main->{_specific} = $current->{_specific} |
129 | if $current; |
107 | if $current; |
130 | |
108 | |
131 | _set_current $main; |
109 | _set_current $main; |
132 | |
110 | |
133 | sub current() { $current } |
111 | sub current() { $current } # [DEPRECATED] |
134 | |
112 | |
135 | =item $idle |
113 | =item $Coro::idle |
136 | |
114 | |
137 | A callback that is called whenever the scheduler finds no ready coroutines |
115 | This variable is mainly useful to integrate Coro into event loops. It is |
138 | to run. The default implementation prints "FATAL: deadlock detected" and |
116 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
139 | exits, because the program has no other way to continue. |
117 | pretty low-level functionality. |
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118 | |
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119 | This variable stores a callback that is called whenever the scheduler |
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120 | finds no ready coroutines to run. The default implementation prints |
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121 | "FATAL: deadlock detected" and exits, because the program has no other way |
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122 | to continue. |
140 | |
123 | |
141 | This hook is overwritten by modules such as C<Coro::Timer> and |
124 | 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 |
125 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
143 | coroutine so the scheduler can run it. |
126 | coroutine so the scheduler can run it. |
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127 | |
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128 | Note that the callback I<must not>, under any circumstances, block |
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129 | the current coroutine. Normally, this is achieved by having an "idle |
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130 | coroutine" that calls the event loop and then blocks again, and then |
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131 | readying that coroutine in the idle handler. |
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132 | |
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133 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
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134 | technique. |
144 | |
135 | |
145 | Please note that if your callback recursively invokes perl (e.g. for event |
136 | Please note that if your callback recursively invokes perl (e.g. for event |
146 | handlers), then it must be prepared to be called recursively itself. |
137 | handlers), then it must be prepared to be called recursively itself. |
147 | |
138 | |
148 | =cut |
139 | =cut |
… | |
… | |
178 | } |
169 | } |
179 | }; |
170 | }; |
180 | $manager->desc ("[coro manager]"); |
171 | $manager->desc ("[coro manager]"); |
181 | $manager->prio (PRIO_MAX); |
172 | $manager->prio (PRIO_MAX); |
182 | |
173 | |
183 | # static methods. not really. |
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184 | |
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185 | =back |
174 | =back |
186 | |
175 | |
187 | =head2 STATIC METHODS |
176 | =head2 SIMPLE COROUTINE CREATION |
188 | |
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189 | Static methods are actually functions that operate on the current coroutine only. |
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190 | |
177 | |
191 | =over 4 |
178 | =over 4 |
192 | |
179 | |
193 | =item async { ... } [@args...] |
180 | =item async { ... } [@args...] |
194 | |
181 | |
195 | Create a new asynchronous coroutine and return it's coroutine object |
182 | Create a new coroutine and return it's coroutine object (usually |
196 | (usually unused). When the sub returns the new coroutine is automatically |
183 | unused). The coroutine will be put into the ready queue, so |
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184 | it will start running automatically on the next scheduler run. |
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185 | |
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186 | The first argument is a codeblock/closure that should be executed in the |
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187 | coroutine. When it returns argument returns the coroutine is automatically |
197 | terminated. |
188 | terminated. |
198 | |
189 | |
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190 | The remaining arguments are passed as arguments to the closure. |
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191 | |
199 | See the C<Coro::State::new> constructor for info about the coroutine |
192 | See the C<Coro::State::new> constructor for info about the coroutine |
200 | environment in which coroutines run. |
193 | environment in which coroutines are executed. |
201 | |
194 | |
202 | Calling C<exit> in a coroutine will do the same as calling exit outside |
195 | 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, |
196 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
204 | just as it would in the main program. |
197 | just as it would in the main program. |
205 | |
198 | |
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199 | If you do not want that, you can provide a default C<die> handler, or |
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200 | simply avoid dieing (by use of C<eval>). |
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201 | |
206 | # create a new coroutine that just prints its arguments |
202 | Example: Create a new coroutine that just prints its arguments. |
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203 | |
207 | async { |
204 | async { |
208 | print "@_\n"; |
205 | print "@_\n"; |
209 | } 1,2,3,4; |
206 | } 1,2,3,4; |
210 | |
207 | |
211 | =cut |
208 | =cut |
… | |
… | |
217 | } |
214 | } |
218 | |
215 | |
219 | =item async_pool { ... } [@args...] |
216 | =item async_pool { ... } [@args...] |
220 | |
217 | |
221 | Similar to C<async>, but uses a coroutine pool, so you should not call |
218 | 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 |
219 | terminate or join on it (although you are allowed to), and you get a |
223 | that might have executed other code already (which can be good or bad :). |
220 | coroutine that might have executed other code already (which can be good |
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221 | or bad :). |
224 | |
222 | |
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223 | On the plus side, this function is faster than creating (and destroying) |
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224 | a completely new coroutine, so if you need a lot of generic coroutines in |
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225 | quick successsion, use C<async_pool>, not C<async>. |
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226 | |
225 | Also, the block is executed in an C<eval> context and a warning will be |
227 | The code 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 |
228 | 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> |
229 | 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, |
230 | will not work in the expected way, unless you call terminate or cancel, |
229 | which somehow defeats the purpose of pooling. |
231 | which somehow defeats the purpose of pooling (but is fine in the |
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232 | exceptional case). |
230 | |
233 | |
231 | The priority will be reset to C<0> after each job, tracing will be |
234 | The priority will be reset to C<0> after each run, tracing will be |
232 | disabled, the description will be reset and the default output filehandle |
235 | disabled, the description will be reset and the default output filehandle |
233 | gets restored, so you can change alkl these. Otherwise the coroutine will |
236 | gets restored, so you can change all these. Otherwise the coroutine will |
234 | be re-used "as-is": most notably if you change other per-coroutine global |
237 | 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 |
238 | stuff such as C<$/> you I<must needs> to revert that change, which is most |
236 | done by using local as in C< local $/ >. |
239 | simply done by using local as in: C< local $/ >. |
237 | |
240 | |
238 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
241 | The pool size is limited to C<8> idle coroutines (this can be adjusted by |
239 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
242 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
240 | required. |
243 | required. |
241 | |
244 | |
242 | If you are concerned about pooled coroutines growing a lot because a |
245 | 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 |
246 | 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 |
247 | { 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 |
248 | addition to that, when the stacks used by a handler grows larger than 16kb |
246 | (adjustable with $Coro::POOL_RSS) it will also exit. |
249 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
247 | |
250 | |
248 | =cut |
251 | =cut |
249 | |
252 | |
250 | our $POOL_SIZE = 8; |
253 | our $POOL_SIZE = 8; |
251 | our $POOL_RSS = 16 * 1024; |
254 | our $POOL_RSS = 16 * 1024; |
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277 | $coro->ready; |
280 | $coro->ready; |
278 | |
281 | |
279 | $coro |
282 | $coro |
280 | } |
283 | } |
281 | |
284 | |
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285 | =back |
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286 | |
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287 | =head2 STATIC METHODS |
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288 | |
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289 | Static methods are actually functions that operate on the current coroutine. |
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290 | |
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291 | =over 4 |
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292 | |
282 | =item schedule |
293 | =item schedule |
283 | |
294 | |
284 | Calls the scheduler. Please note that the current coroutine will not be put |
295 | Calls the scheduler. The scheduler will find the next coroutine that is |
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296 | to be run from the ready queue and switches to it. The next coroutine |
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297 | to be run is simply the one with the highest priority that is longest |
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298 | in its ready queue. If there is no coroutine ready, it will clal the |
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299 | C<$Coro::idle> hook. |
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300 | |
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301 | Please note that the current coroutine will I<not> be put into the ready |
285 | into the ready queue, so calling this function usually means you will |
302 | queue, so calling this function usually means you will never be called |
286 | never be called again unless something else (e.g. an event handler) calls |
303 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
287 | ready. |
304 | thus waking you up. |
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305 | |
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306 | This makes C<schedule> I<the> generic method to use to block the current |
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307 | coroutine and wait for events: first you remember the current coroutine in |
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308 | a variable, then arrange for some callback of yours to call C<< ->ready |
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309 | >> on that once some event happens, and last you call C<schedule> to put |
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310 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
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311 | so you need to check wether the event indeed happened, e.g. by storing the |
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312 | status in a variable. |
288 | |
313 | |
289 | The canonical way to wait on external events is this: |
314 | The canonical way to wait on external events is this: |
290 | |
315 | |
291 | { |
316 | { |
292 | # remember current coroutine |
317 | # remember current coroutine |
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… | |
305 | Coro::schedule while $current; |
330 | Coro::schedule while $current; |
306 | } |
331 | } |
307 | |
332 | |
308 | =item cede |
333 | =item cede |
309 | |
334 | |
310 | "Cede" to other coroutines. This function puts the current coroutine into the |
335 | "Cede" to other coroutines. This function puts the current coroutine into |
311 | ready queue and calls C<schedule>, which has the effect of giving up the |
336 | the ready queue and calls C<schedule>, which has the effect of giving |
312 | current "timeslice" to other coroutines of the same or higher priority. |
337 | up the current "timeslice" to other coroutines of the same or higher |
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338 | priority. Once your coroutine gets its turn again it will automatically be |
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339 | resumed. |
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340 | |
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341 | This function is often called C<yield> in other languages. |
313 | |
342 | |
314 | =item Coro::cede_notself |
343 | =item Coro::cede_notself |
315 | |
344 | |
316 | Works like cede, but is not exported by default and will cede to any |
345 | Works like cede, but is not exported by default and will cede to I<any> |
317 | coroutine, regardless of priority, once. |
346 | coroutine, regardless of priority. This is useful sometimes to ensure |
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347 | progress is made. |
318 | |
348 | |
319 | =item terminate [arg...] |
349 | =item terminate [arg...] |
320 | |
350 | |
321 | Terminates the current coroutine with the given status values (see L<cancel>). |
351 | Terminates the current coroutine with the given status values (see L<cancel>). |
322 | |
352 | |
323 | =item killall |
353 | =item killall |
324 | |
354 | |
325 | Kills/terminates/cancels all coroutines except the currently running |
355 | 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 |
356 | 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. |
357 | usually only one of them should inherit the running coroutines. |
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358 | |
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359 | Note that while this will try to free some of the main programs resources, |
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360 | you cnanot free all of them, so if a coroutine that is not the main |
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361 | program calls this function, there will be some one-time resource leak. |
328 | |
362 | |
329 | =cut |
363 | =cut |
330 | |
364 | |
331 | sub terminate { |
365 | sub terminate { |
332 | $current->cancel (@_); |
366 | $current->cancel (@_); |
… | |
… | |
339 | } |
373 | } |
340 | } |
374 | } |
341 | |
375 | |
342 | =back |
376 | =back |
343 | |
377 | |
344 | # dynamic methods |
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345 | |
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346 | =head2 COROUTINE METHODS |
378 | =head2 COROUTINE METHODS |
347 | |
379 | |
348 | These are the methods you can call on coroutine objects. |
380 | These are the methods you can call on coroutine objects (or to create |
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381 | them). |
349 | |
382 | |
350 | =over 4 |
383 | =over 4 |
351 | |
384 | |
352 | =item new Coro \&sub [, @args...] |
385 | =item new Coro \&sub [, @args...] |
353 | |
386 | |
354 | Create a new coroutine and return it. When the sub returns the coroutine |
387 | Create a new coroutine and return it. When the sub returns, the coroutine |
355 | automatically terminates as if C<terminate> with the returned values were |
388 | 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 |
389 | called. To make the coroutine run you must first put it into the ready |
357 | by calling the ready method. |
390 | queue by calling the ready method. |
358 | |
391 | |
359 | See C<async> and C<Coro::State::new> for additional info about the |
392 | See C<async> and C<Coro::State::new> for additional info about the |
360 | coroutine environment. |
393 | coroutine environment. |
361 | |
394 | |
362 | =cut |
395 | =cut |
… | |
… | |
371 | $class->SUPER::new (\&_run_coro, @_) |
404 | $class->SUPER::new (\&_run_coro, @_) |
372 | } |
405 | } |
373 | |
406 | |
374 | =item $success = $coroutine->ready |
407 | =item $success = $coroutine->ready |
375 | |
408 | |
376 | Put the given coroutine into the ready queue (according to it's priority) |
409 | Put the given coroutine into the end of its ready queue (there is one |
377 | and return true. If the coroutine is already in the ready queue, do nothing |
410 | queue for each priority) and return true. If the coroutine is already in |
378 | and return false. |
411 | the ready queue, do nothing and return false. |
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412 | |
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413 | This ensures that the scheduler will resume this coroutine automatically |
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414 | once all the coroutines of higher priority and all coroutines of the same |
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415 | priority that were put into the ready queue earlier have been resumed. |
379 | |
416 | |
380 | =item $is_ready = $coroutine->is_ready |
417 | =item $is_ready = $coroutine->is_ready |
381 | |
418 | |
382 | Return wether the coroutine is currently the ready queue or not, |
419 | Return wether the coroutine is currently the ready queue or not, |
383 | |
420 | |
… | |
… | |
404 | |
441 | |
405 | =item $coroutine->join |
442 | =item $coroutine->join |
406 | |
443 | |
407 | Wait until the coroutine terminates and return any values given to the |
444 | Wait until the coroutine terminates and return any values given to the |
408 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
445 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
409 | from multiple coroutines. |
446 | from multiple coroutines, and all will be resumed and given the status |
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447 | return once the C<$coroutine> terminates. |
410 | |
448 | |
411 | =cut |
449 | =cut |
412 | |
450 | |
413 | sub join { |
451 | sub join { |
414 | my $self = shift; |
452 | my $self = shift; |
… | |
… | |
429 | |
467 | |
430 | =item $coroutine->on_destroy (\&cb) |
468 | =item $coroutine->on_destroy (\&cb) |
431 | |
469 | |
432 | Registers a callback that is called when this coroutine gets destroyed, |
470 | Registers a callback that is called when this coroutine gets destroyed, |
433 | but before it is joined. The callback gets passed the terminate arguments, |
471 | but before it is joined. The callback gets passed the terminate arguments, |
434 | if any. |
472 | if any, and I<must not> die, under any circumstances. |
435 | |
473 | |
436 | =cut |
474 | =cut |
437 | |
475 | |
438 | sub on_destroy { |
476 | sub on_destroy { |
439 | my ($self, $cb) = @_; |
477 | my ($self, $cb) = @_; |
… | |
… | |
507 | =over 4 |
545 | =over 4 |
508 | |
546 | |
509 | =item Coro::nready |
547 | =item Coro::nready |
510 | |
548 | |
511 | Returns the number of coroutines that are currently in the ready state, |
549 | 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 |
550 | i.e. that can be switched to by calling C<schedule> directory or |
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551 | indirectly. The value C<0> means that the only runnable coroutine is the |
513 | coroutine is the currently running one, so C<cede> would have no effect, |
552 | currently running one, so C<cede> would have no effect, and C<schedule> |
514 | and C<schedule> would cause a deadlock unless there is an idle handler |
553 | would cause a deadlock unless there is an idle handler that wakes up some |
515 | that wakes up some coroutines. |
554 | coroutines. |
516 | |
555 | |
517 | =item my $guard = Coro::guard { ... } |
556 | =item my $guard = Coro::guard { ... } |
518 | |
557 | |
519 | This creates and returns a guard object. Nothing happens until the object |
558 | 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 |
559 | gets destroyed, in which case the codeblock given as argument will be |
… | |
… | |
549 | |
588 | |
550 | |
589 | |
551 | =item unblock_sub { ... } |
590 | =item unblock_sub { ... } |
552 | |
591 | |
553 | This utility function takes a BLOCK or code reference and "unblocks" it, |
592 | 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 |
593 | returning a new coderef. Unblocking means that calling the new coderef |
555 | immediately without blocking, returning nothing, while the original code |
594 | will return immediately without blocking, returning nothing, while the |
556 | ref will be called (with parameters) from within its own coroutine. |
595 | original code ref will be called (with parameters) from within another |
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|
596 | coroutine. |
557 | |
597 | |
558 | The reason this function exists is that many event libraries (such as the |
598 | 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 |
599 | 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, |
600 | of thread-safety). This means you must not block within event callbacks, |
561 | otherwise you might suffer from crashes or worse. |
601 | otherwise you might suffer from crashes or worse. The only event library |
|
|
602 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
562 | |
603 | |
563 | This function allows your callbacks to block by executing them in another |
604 | 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 |
605 | 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 |
606 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
566 | disk. |
607 | disk, for example. |
567 | |
608 | |
568 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
609 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
569 | creating event callbacks that want to block. |
610 | creating event callbacks that want to block. |
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611 | |
|
|
612 | If your handler does not plan to block (e.g. simply sends a message to |
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|
613 | another coroutine, or puts some other coroutine into the ready queue), |
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614 | there is no reason to use C<unblock_sub>. |
570 | |
615 | |
571 | =cut |
616 | =cut |
572 | |
617 | |
573 | our @unblock_queue; |
618 | our @unblock_queue; |
574 | |
619 | |
… | |
… | |
606 | |
651 | |
607 | 1; |
652 | 1; |
608 | |
653 | |
609 | =head1 BUGS/LIMITATIONS |
654 | =head1 BUGS/LIMITATIONS |
610 | |
655 | |
611 | - you must make very sure that no coro is still active on global |
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612 | destruction. very bad things might happen otherwise (usually segfaults). |
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|
613 | |
|
|
614 | - this module is not thread-safe. You should only ever use this module |
656 | This module is not perl-pseudo-thread-safe. You should only ever use this |
615 | from the same thread (this requirement might be loosened in the future |
657 | module from the same thread (this requirement might be removed in the |
616 | to allow per-thread schedulers, but Coro::State does not yet allow |
658 | future to allow per-thread schedulers, but Coro::State does not yet allow |
617 | this). |
659 | this). I recommend disabling thread support and using processes, as this |
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|
660 | is much faster and uses less memory. |
618 | |
661 | |
619 | =head1 SEE ALSO |
662 | =head1 SEE ALSO |
620 | |
663 | |
621 | Lower level Configuration, Coroutine Environment: L<Coro::State>. |
664 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
622 | |
665 | |
623 | Debugging: L<Coro::Debug>. |
666 | Debugging: L<Coro::Debug>. |
624 | |
667 | |
625 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
668 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
626 | |
669 | |
627 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
670 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
628 | |
671 | |
629 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>. |
672 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
630 | |
673 | |
631 | Compatibility: L<Coro::LWP>, L<Coro::Storable>, L<Coro::Select>. |
674 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
632 | |
675 | |
633 | Embedding: L<Coro::MakeMaker>. |
676 | XS API: L<Coro::MakeMaker>. |
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677 | |
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678 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
634 | |
679 | |
635 | =head1 AUTHOR |
680 | =head1 AUTHOR |
636 | |
681 | |
637 | Marc Lehmann <schmorp@schmorp.de> |
682 | Marc Lehmann <schmorp@schmorp.de> |
638 | http://home.schmorp.de/ |
683 | http://home.schmorp.de/ |