… | |
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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 |
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11 | print "2\n"; |
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12 | cede; # yield back to main |
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13 | print "4\n"; |
11 | }; |
14 | }; |
12 | |
15 | print "1\n"; |
13 | # alternatively create an async coroutine like this: |
16 | cede; # yield to coroutine |
14 | |
17 | print "3\n"; |
15 | sub some_func : Coro { |
18 | cede; # and again |
16 | # some more async code |
19 | |
17 | } |
20 | # use locking |
18 | |
21 | my $lock = new Coro::Semaphore; |
19 | cede; |
22 | my $locked; |
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23 | |
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24 | $lock->down; |
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25 | $locked = 1; |
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26 | $lock->up; |
20 | |
27 | |
21 | =head1 DESCRIPTION |
28 | =head1 DESCRIPTION |
22 | |
29 | |
23 | This module collection manages coroutines. Coroutines are similar |
30 | This module collection manages coroutines. Coroutines are similar to |
24 | 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 |
25 | machines. The specific flavor of coroutine used in this module also |
32 | on SMP machines. The specific flavor of coroutine used in this module |
26 | guarantees you that it will not switch between coroutines unless |
33 | also guarantees you that it will not switch between coroutines unless |
27 | necessary, at easily-identified points in your program, so locking and |
34 | necessary, at easily-identified points in your program, so locking and |
28 | parallel access are rarely an issue, making coroutine programming much |
35 | parallel access are rarely an issue, making coroutine programming much |
29 | safer than threads programming. |
36 | safer and easier than threads programming. |
30 | |
37 | |
31 | (Perl, however, does not natively support real threads but instead does a |
38 | Unlike a normal perl program, however, coroutines allow you to have |
32 | very slow and memory-intensive emulation of processes using threads. This |
39 | multiple running interpreters that share data, which is especially useful |
33 | is a performance win on Windows machines, and a loss everywhere else). |
40 | to code pseudo-parallel processes and for event-based programming, such as |
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41 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
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42 | learn more. |
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43 | |
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44 | Coroutines are also useful because Perl has no support for threads (the so |
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45 | called "threads" that perl offers are nothing more than the (bad) process |
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46 | emulation coming from the Windows platform: On standard operating systems |
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47 | they serve no purpose whatsoever, except by making your programs slow and |
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48 | making them use a lot of memory. Best disable them when building perl, or |
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49 | aks your software vendor/distributor to do it for you). |
34 | |
50 | |
35 | In this module, coroutines are defined as "callchain + lexical variables + |
51 | In this module, coroutines are defined as "callchain + lexical variables + |
36 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
52 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
37 | its own set of lexicals and its own set of perls most important global |
53 | its own set of lexicals and its own set of perls most important global |
38 | variables. |
54 | variables (see L<Coro::State> for more configuration). |
39 | |
55 | |
40 | =cut |
56 | =cut |
41 | |
57 | |
42 | package Coro; |
58 | package Coro; |
43 | |
59 | |
… | |
… | |
50 | |
66 | |
51 | our $idle; # idle handler |
67 | our $idle; # idle handler |
52 | our $main; # main coroutine |
68 | our $main; # main coroutine |
53 | our $current; # current coroutine |
69 | our $current; # current coroutine |
54 | |
70 | |
55 | our $VERSION = '4.0'; |
71 | our $VERSION = 4.743; |
56 | |
72 | |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
73 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
58 | our %EXPORT_TAGS = ( |
74 | our %EXPORT_TAGS = ( |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
75 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
60 | ); |
76 | ); |
61 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
77 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
62 | |
78 | |
63 | { |
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64 | my @async; |
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65 | my $init; |
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66 | |
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67 | # this way of handling attributes simply is NOT scalable ;() |
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68 | sub import { |
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69 | no strict 'refs'; |
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70 | |
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71 | Coro->export_to_level (1, @_); |
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72 | |
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73 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
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74 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
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75 | my ($package, $ref) = (shift, shift); |
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76 | my @attrs; |
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77 | for (@_) { |
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78 | if ($_ eq "Coro") { |
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79 | push @async, $ref; |
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80 | unless ($init++) { |
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81 | eval q{ |
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82 | sub INIT { |
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83 | &async(pop @async) while @async; |
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84 | } |
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85 | }; |
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86 | } |
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87 | } else { |
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88 | push @attrs, $_; |
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89 | } |
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90 | } |
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91 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
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92 | }; |
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93 | } |
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94 | |
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95 | } |
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96 | |
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97 | =over 4 |
79 | =over 4 |
98 | |
80 | |
99 | =item $main |
81 | =item $Coro::main |
100 | |
82 | |
101 | This coroutine represents the main program. |
83 | This variable stores the coroutine object that represents the main |
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84 | program. While you cna C<ready> it and do most other things you can do to |
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85 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
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86 | wether you are running in the main program or not. |
102 | |
87 | |
103 | =cut |
88 | =cut |
104 | |
89 | |
105 | $main = new Coro; |
90 | $main = new Coro; |
106 | |
91 | |
107 | =item $current (or as function: current) |
92 | =item $Coro::current |
108 | |
93 | |
109 | The current coroutine (the last coroutine switched to). The initial value |
94 | The coroutine object representing the current coroutine (the last |
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95 | coroutine that the Coro scheduler switched to). The initial value is |
110 | is C<$main> (of course). |
96 | C<$main> (of course). |
111 | |
97 | |
112 | This variable is B<strictly> I<read-only>. It is provided for performance |
98 | This variable is B<strictly> I<read-only>. You can take copies of the |
113 | reasons. If performance is not essential you are encouraged to use the |
99 | value stored in it and use it as any other coroutine object, but you must |
114 | C<Coro::current> function instead. |
100 | not otherwise modify the variable itself. |
115 | |
101 | |
116 | =cut |
102 | =cut |
117 | |
103 | |
118 | $main->{desc} = "[main::]"; |
104 | $main->{desc} = "[main::]"; |
119 | |
105 | |
… | |
… | |
121 | $main->{_specific} = $current->{_specific} |
107 | $main->{_specific} = $current->{_specific} |
122 | if $current; |
108 | if $current; |
123 | |
109 | |
124 | _set_current $main; |
110 | _set_current $main; |
125 | |
111 | |
126 | sub current() { $current } |
112 | sub current() { $current } # [DEPRECATED] |
127 | |
113 | |
128 | =item $idle |
114 | =item $Coro::idle |
129 | |
115 | |
130 | A callback that is called whenever the scheduler finds no ready coroutines |
116 | This variable is mainly useful to integrate Coro into event loops. It is |
131 | to run. The default implementation prints "FATAL: deadlock detected" and |
117 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
132 | exits, because the program has no other way to continue. |
118 | pretty low-level functionality. |
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119 | |
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120 | This variable stores a callback that is called whenever the scheduler |
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121 | finds no ready coroutines to run. The default implementation prints |
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122 | "FATAL: deadlock detected" and exits, because the program has no other way |
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123 | to continue. |
133 | |
124 | |
134 | This hook is overwritten by modules such as C<Coro::Timer> and |
125 | This hook is overwritten by modules such as C<Coro::Timer> and |
135 | C<Coro::Event> to wait on an external event that hopefully wake up a |
126 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
136 | coroutine so the scheduler can run it. |
127 | coroutine so the scheduler can run it. |
137 | |
128 | |
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129 | Note that the callback I<must not>, under any circumstances, block |
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130 | the current coroutine. Normally, this is achieved by having an "idle |
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131 | coroutine" that calls the event loop and then blocks again, and then |
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132 | readying that coroutine in the idle handler. |
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133 | |
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134 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
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135 | technique. |
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136 | |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
137 | Please note that if your callback recursively invokes perl (e.g. for event |
139 | handlers), then it must be prepared to be called recursively. |
138 | handlers), then it must be prepared to be called recursively itself. |
140 | |
139 | |
141 | =cut |
140 | =cut |
142 | |
141 | |
143 | $idle = sub { |
142 | $idle = sub { |
144 | require Carp; |
143 | require Carp; |
… | |
… | |
171 | } |
170 | } |
172 | }; |
171 | }; |
173 | $manager->desc ("[coro manager]"); |
172 | $manager->desc ("[coro manager]"); |
174 | $manager->prio (PRIO_MAX); |
173 | $manager->prio (PRIO_MAX); |
175 | |
174 | |
176 | # static methods. not really. |
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177 | |
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178 | =back |
175 | =back |
179 | |
176 | |
180 | =head2 STATIC METHODS |
177 | =head2 SIMPLE COROUTINE CREATION |
181 | |
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182 | Static methods are actually functions that operate on the current coroutine only. |
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183 | |
178 | |
184 | =over 4 |
179 | =over 4 |
185 | |
180 | |
186 | =item async { ... } [@args...] |
181 | =item async { ... } [@args...] |
187 | |
182 | |
188 | Create a new asynchronous coroutine and return it's coroutine object |
183 | Create a new coroutine and return it's coroutine object (usually |
189 | (usually unused). When the sub returns the new coroutine is automatically |
184 | unused). The coroutine will be put into the ready queue, so |
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185 | it will start running automatically on the next scheduler run. |
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186 | |
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187 | The first argument is a codeblock/closure that should be executed in the |
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188 | coroutine. When it returns argument returns the coroutine is automatically |
190 | terminated. |
189 | terminated. |
191 | |
190 | |
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191 | The remaining arguments are passed as arguments to the closure. |
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192 | |
192 | See the C<Coro::State::new> constructor for info about the coroutine |
193 | See the C<Coro::State::new> constructor for info about the coroutine |
193 | environment. |
194 | environment in which coroutines are executed. |
194 | |
195 | |
195 | Calling C<exit> in a coroutine will do the same as calling exit outside |
196 | Calling C<exit> in a coroutine will do the same as calling exit outside |
196 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
197 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
197 | just as it would in the main program. |
198 | just as it would in the main program. |
198 | |
199 | |
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200 | If you do not want that, you can provide a default C<die> handler, or |
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201 | simply avoid dieing (by use of C<eval>). |
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202 | |
199 | # create a new coroutine that just prints its arguments |
203 | Example: Create a new coroutine that just prints its arguments. |
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204 | |
200 | async { |
205 | async { |
201 | print "@_\n"; |
206 | print "@_\n"; |
202 | } 1,2,3,4; |
207 | } 1,2,3,4; |
203 | |
208 | |
204 | =cut |
209 | =cut |
… | |
… | |
210 | } |
215 | } |
211 | |
216 | |
212 | =item async_pool { ... } [@args...] |
217 | =item async_pool { ... } [@args...] |
213 | |
218 | |
214 | Similar to C<async>, but uses a coroutine pool, so you should not call |
219 | Similar to C<async>, but uses a coroutine pool, so you should not call |
215 | terminate or join (although you are allowed to), and you get a coroutine |
220 | terminate or join on it (although you are allowed to), and you get a |
216 | that might have executed other code already (which can be good or bad :). |
221 | coroutine that might have executed other code already (which can be good |
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222 | or bad :). |
217 | |
223 | |
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224 | On the plus side, this function is faster than creating (and destroying) |
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225 | a completely new coroutine, so if you need a lot of generic coroutines in |
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226 | quick successsion, use C<async_pool>, not C<async>. |
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227 | |
218 | Also, the block is executed in an C<eval> context and a warning will be |
228 | The code block is executed in an C<eval> context and a warning will be |
219 | issued in case of an exception instead of terminating the program, as |
229 | issued in case of an exception instead of terminating the program, as |
220 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
230 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
221 | will not work in the expected way, unless you call terminate or cancel, |
231 | will not work in the expected way, unless you call terminate or cancel, |
222 | which somehow defeats the purpose of pooling. |
232 | which somehow defeats the purpose of pooling (but is fine in the |
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233 | exceptional case). |
223 | |
234 | |
224 | The priority will be reset to C<0> after each job, tracing will be |
235 | The priority will be reset to C<0> after each run, tracing will be |
225 | disabled, the description will be reset and the default output filehandle |
236 | disabled, the description will be reset and the default output filehandle |
226 | gets restored, so you can change alkl these. Otherwise the coroutine will |
237 | gets restored, so you can change all these. Otherwise the coroutine will |
227 | be re-used "as-is": most notably if you change other per-coroutine global |
238 | be re-used "as-is": most notably if you change other per-coroutine global |
228 | stuff such as C<$/> you need to revert that change, which is most simply |
239 | stuff such as C<$/> you I<must needs> to revert that change, which is most |
229 | done by using local as in C< local $/ >. |
240 | simply done by using local as in: C< local $/ >. |
230 | |
241 | |
231 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
242 | The pool size is limited to C<8> idle coroutines (this can be adjusted by |
232 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
243 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
233 | required. |
244 | required. |
234 | |
245 | |
235 | If you are concerned about pooled coroutines growing a lot because a |
246 | If you are concerned about pooled coroutines growing a lot because a |
236 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
247 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
237 | { terminate }> once per second or so to slowly replenish the pool. In |
248 | { terminate }> once per second or so to slowly replenish the pool. In |
238 | addition to that, when the stacks used by a handler grows larger than 16kb |
249 | addition to that, when the stacks used by a handler grows larger than 16kb |
239 | (adjustable with $Coro::POOL_RSS) it will also exit. |
250 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
240 | |
251 | |
241 | =cut |
252 | =cut |
242 | |
253 | |
243 | our $POOL_SIZE = 8; |
254 | our $POOL_SIZE = 8; |
244 | our $POOL_RSS = 16 * 1024; |
255 | our $POOL_RSS = 16 * 1024; |
… | |
… | |
255 | _pool_2 $cb; |
266 | _pool_2 $cb; |
256 | &schedule; |
267 | &schedule; |
257 | } |
268 | } |
258 | }; |
269 | }; |
259 | |
270 | |
260 | last if $@ eq "\3terminate\2\n"; |
271 | last if $@ eq "\3async_pool terminate\2\n"; |
261 | warn $@ if $@; |
272 | warn $@ if $@; |
262 | } |
273 | } |
263 | } |
274 | } |
264 | |
275 | |
265 | sub async_pool(&@) { |
276 | sub async_pool(&@) { |
… | |
… | |
270 | $coro->ready; |
281 | $coro->ready; |
271 | |
282 | |
272 | $coro |
283 | $coro |
273 | } |
284 | } |
274 | |
285 | |
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286 | =back |
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287 | |
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288 | =head2 STATIC METHODS |
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289 | |
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290 | Static methods are actually functions that operate on the current coroutine. |
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291 | |
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292 | =over 4 |
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293 | |
275 | =item schedule |
294 | =item schedule |
276 | |
295 | |
277 | Calls the scheduler. Please note that the current coroutine will not be put |
296 | Calls the scheduler. The scheduler will find the next coroutine that is |
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297 | to be run from the ready queue and switches to it. The next coroutine |
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298 | to be run is simply the one with the highest priority that is longest |
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299 | in its ready queue. If there is no coroutine ready, it will clal the |
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300 | C<$Coro::idle> hook. |
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301 | |
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302 | Please note that the current coroutine will I<not> be put into the ready |
278 | into the ready queue, so calling this function usually means you will |
303 | queue, so calling this function usually means you will never be called |
279 | never be called again unless something else (e.g. an event handler) calls |
304 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
280 | ready. |
305 | thus waking you up. |
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306 | |
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307 | This makes C<schedule> I<the> generic method to use to block the current |
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308 | coroutine and wait for events: first you remember the current coroutine in |
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309 | a variable, then arrange for some callback of yours to call C<< ->ready |
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310 | >> on that once some event happens, and last you call C<schedule> to put |
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311 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
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312 | so you need to check wether the event indeed happened, e.g. by storing the |
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313 | status in a variable. |
281 | |
314 | |
282 | The canonical way to wait on external events is this: |
315 | The canonical way to wait on external events is this: |
283 | |
316 | |
284 | { |
317 | { |
285 | # remember current coroutine |
318 | # remember current coroutine |
… | |
… | |
298 | Coro::schedule while $current; |
331 | Coro::schedule while $current; |
299 | } |
332 | } |
300 | |
333 | |
301 | =item cede |
334 | =item cede |
302 | |
335 | |
303 | "Cede" to other coroutines. This function puts the current coroutine into the |
336 | "Cede" to other coroutines. This function puts the current coroutine into |
304 | ready queue and calls C<schedule>, which has the effect of giving up the |
337 | the ready queue and calls C<schedule>, which has the effect of giving |
305 | current "timeslice" to other coroutines of the same or higher priority. |
338 | up the current "timeslice" to other coroutines of the same or higher |
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339 | priority. Once your coroutine gets its turn again it will automatically be |
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340 | resumed. |
306 | |
341 | |
307 | Returns true if at least one coroutine switch has happened. |
342 | This function is often called C<yield> in other languages. |
308 | |
343 | |
309 | =item Coro::cede_notself |
344 | =item Coro::cede_notself |
310 | |
345 | |
311 | Works like cede, but is not exported by default and will cede to any |
346 | Works like cede, but is not exported by default and will cede to I<any> |
312 | coroutine, regardless of priority, once. |
347 | coroutine, regardless of priority. This is useful sometimes to ensure |
313 | |
348 | progress is made. |
314 | Returns true if at least one coroutine switch has happened. |
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315 | |
349 | |
316 | =item terminate [arg...] |
350 | =item terminate [arg...] |
317 | |
351 | |
318 | Terminates the current coroutine with the given status values (see L<cancel>). |
352 | Terminates the current coroutine with the given status values (see L<cancel>). |
319 | |
353 | |
320 | =item killall |
354 | =item killall |
321 | |
355 | |
322 | Kills/terminates/cancels all coroutines except the currently running |
356 | Kills/terminates/cancels all coroutines except the currently running |
323 | one. This is useful after a fork, either in the child or the parent, as |
357 | one. This is useful after a fork, either in the child or the parent, as |
324 | usually only one of them should inherit the running coroutines. |
358 | usually only one of them should inherit the running coroutines. |
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359 | |
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360 | Note that while this will try to free some of the main programs resources, |
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361 | you cnanot free all of them, so if a coroutine that is not the main |
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362 | program calls this function, there will be some one-time resource leak. |
325 | |
363 | |
326 | =cut |
364 | =cut |
327 | |
365 | |
328 | sub terminate { |
366 | sub terminate { |
329 | $current->cancel (@_); |
367 | $current->cancel (@_); |
… | |
… | |
336 | } |
374 | } |
337 | } |
375 | } |
338 | |
376 | |
339 | =back |
377 | =back |
340 | |
378 | |
341 | # dynamic methods |
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342 | |
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343 | =head2 COROUTINE METHODS |
379 | =head2 COROUTINE METHODS |
344 | |
380 | |
345 | These are the methods you can call on coroutine objects. |
381 | These are the methods you can call on coroutine objects (or to create |
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382 | them). |
346 | |
383 | |
347 | =over 4 |
384 | =over 4 |
348 | |
385 | |
349 | =item new Coro \&sub [, @args...] |
386 | =item new Coro \&sub [, @args...] |
350 | |
387 | |
351 | Create a new coroutine and return it. When the sub returns the coroutine |
388 | Create a new coroutine and return it. When the sub returns, the coroutine |
352 | automatically terminates as if C<terminate> with the returned values were |
389 | automatically terminates as if C<terminate> with the returned values were |
353 | called. To make the coroutine run you must first put it into the ready queue |
390 | called. To make the coroutine run you must first put it into the ready |
354 | by calling the ready method. |
391 | queue by calling the ready method. |
355 | |
392 | |
356 | See C<async> and C<Coro::State::new> for additional info about the |
393 | See C<async> and C<Coro::State::new> for additional info about the |
357 | coroutine environment. |
394 | coroutine environment. |
358 | |
395 | |
359 | =cut |
396 | =cut |
… | |
… | |
368 | $class->SUPER::new (\&_run_coro, @_) |
405 | $class->SUPER::new (\&_run_coro, @_) |
369 | } |
406 | } |
370 | |
407 | |
371 | =item $success = $coroutine->ready |
408 | =item $success = $coroutine->ready |
372 | |
409 | |
373 | Put the given coroutine into the ready queue (according to it's priority) |
410 | Put the given coroutine into the end of its ready queue (there is one |
374 | and return true. If the coroutine is already in the ready queue, do nothing |
411 | queue for each priority) and return true. If the coroutine is already in |
375 | and return false. |
412 | the ready queue, do nothing and return false. |
|
|
413 | |
|
|
414 | This ensures that the scheduler will resume this coroutine automatically |
|
|
415 | once all the coroutines of higher priority and all coroutines of the same |
|
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416 | priority that were put into the ready queue earlier have been resumed. |
376 | |
417 | |
377 | =item $is_ready = $coroutine->is_ready |
418 | =item $is_ready = $coroutine->is_ready |
378 | |
419 | |
379 | Return wether the coroutine is currently the ready queue or not, |
420 | Return wether the coroutine is currently the ready queue or not, |
380 | |
421 | |
… | |
… | |
401 | |
442 | |
402 | =item $coroutine->join |
443 | =item $coroutine->join |
403 | |
444 | |
404 | Wait until the coroutine terminates and return any values given to the |
445 | Wait until the coroutine terminates and return any values given to the |
405 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
446 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
406 | from multiple coroutines. |
447 | from multiple coroutines, and all will be resumed and given the status |
|
|
448 | return once the C<$coroutine> terminates. |
407 | |
449 | |
408 | =cut |
450 | =cut |
409 | |
451 | |
410 | sub join { |
452 | sub join { |
411 | my $self = shift; |
453 | my $self = shift; |
… | |
… | |
426 | |
468 | |
427 | =item $coroutine->on_destroy (\&cb) |
469 | =item $coroutine->on_destroy (\&cb) |
428 | |
470 | |
429 | Registers a callback that is called when this coroutine gets destroyed, |
471 | Registers a callback that is called when this coroutine gets destroyed, |
430 | but before it is joined. The callback gets passed the terminate arguments, |
472 | but before it is joined. The callback gets passed the terminate arguments, |
431 | if any. |
473 | if any, and I<must not> die, under any circumstances. |
432 | |
474 | |
433 | =cut |
475 | =cut |
434 | |
476 | |
435 | sub on_destroy { |
477 | sub on_destroy { |
436 | my ($self, $cb) = @_; |
478 | my ($self, $cb) = @_; |
… | |
… | |
471 | coroutine. This is just a free-form string you can associate with a coroutine. |
513 | coroutine. This is just a free-form string you can associate with a coroutine. |
472 | |
514 | |
473 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
515 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
474 | can modify this member directly if you wish. |
516 | can modify this member directly if you wish. |
475 | |
517 | |
|
|
518 | =item $coroutine->throw ([$scalar]) |
|
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519 | |
|
|
520 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
521 | inside the coroutine at the next convinient point in time (usually after |
|
|
522 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
523 | exception object. |
|
|
524 | |
|
|
525 | The exception object will be thrown "as is" with the specified scalar in |
|
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526 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
527 | (unlike with C<die>). |
|
|
528 | |
|
|
529 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
530 | end itself, although there is no guarentee that the exception will lead to |
|
|
531 | termination, and if the exception isn't caught it might well end the whole |
|
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532 | program. |
|
|
533 | |
476 | =cut |
534 | =cut |
477 | |
535 | |
478 | sub desc { |
536 | sub desc { |
479 | my $old = $_[0]{desc}; |
537 | my $old = $_[0]{desc}; |
480 | $_[0]{desc} = $_[1] if @_ > 1; |
538 | $_[0]{desc} = $_[1] if @_ > 1; |
… | |
… | |
488 | =over 4 |
546 | =over 4 |
489 | |
547 | |
490 | =item Coro::nready |
548 | =item Coro::nready |
491 | |
549 | |
492 | Returns the number of coroutines that are currently in the ready state, |
550 | Returns the number of coroutines that are currently in the ready state, |
493 | i.e. that can be switched to. The value C<0> means that the only runnable |
551 | i.e. that can be switched to by calling C<schedule> directory or |
|
|
552 | indirectly. The value C<0> means that the only runnable coroutine is the |
494 | coroutine is the currently running one, so C<cede> would have no effect, |
553 | currently running one, so C<cede> would have no effect, and C<schedule> |
495 | and C<schedule> would cause a deadlock unless there is an idle handler |
554 | would cause a deadlock unless there is an idle handler that wakes up some |
496 | that wakes up some coroutines. |
555 | coroutines. |
497 | |
556 | |
498 | =item my $guard = Coro::guard { ... } |
557 | =item my $guard = Coro::guard { ... } |
499 | |
558 | |
500 | This creates and returns a guard object. Nothing happens until the object |
559 | This creates and returns a guard object. Nothing happens until the object |
501 | gets destroyed, in which case the codeblock given as argument will be |
560 | gets destroyed, in which case the codeblock given as argument will be |
… | |
… | |
530 | |
589 | |
531 | |
590 | |
532 | =item unblock_sub { ... } |
591 | =item unblock_sub { ... } |
533 | |
592 | |
534 | This utility function takes a BLOCK or code reference and "unblocks" it, |
593 | This utility function takes a BLOCK or code reference and "unblocks" it, |
535 | returning the new coderef. This means that the new coderef will return |
594 | returning a new coderef. Unblocking means that calling the new coderef |
536 | immediately without blocking, returning nothing, while the original code |
595 | will return immediately without blocking, returning nothing, while the |
537 | ref will be called (with parameters) from within its own coroutine. |
596 | original code ref will be called (with parameters) from within another |
|
|
597 | coroutine. |
538 | |
598 | |
539 | The reason this function exists is that many event libraries (such as the |
599 | The reason this function exists is that many event libraries (such as the |
540 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
600 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
541 | of thread-safety). This means you must not block within event callbacks, |
601 | of thread-safety). This means you must not block within event callbacks, |
542 | otherwise you might suffer from crashes or worse. |
602 | otherwise you might suffer from crashes or worse. The only event library |
|
|
603 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
543 | |
604 | |
544 | This function allows your callbacks to block by executing them in another |
605 | This function allows your callbacks to block by executing them in another |
545 | coroutine where it is safe to block. One example where blocking is handy |
606 | coroutine where it is safe to block. One example where blocking is handy |
546 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
607 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
547 | disk. |
608 | disk, for example. |
548 | |
609 | |
549 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
610 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
550 | creating event callbacks that want to block. |
611 | creating event callbacks that want to block. |
|
|
612 | |
|
|
613 | If your handler does not plan to block (e.g. simply sends a message to |
|
|
614 | another coroutine, or puts some other coroutine into the ready queue), |
|
|
615 | there is no reason to use C<unblock_sub>. |
|
|
616 | |
|
|
617 | Note that you also need to use C<unblock_sub> for any other callbacks that |
|
|
618 | are indirectly executed by any C-based event loop. For example, when you |
|
|
619 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
|
|
620 | provides callbacks that are the result of some event callback, then you |
|
|
621 | must not block either, or use C<unblock_sub>. |
551 | |
622 | |
552 | =cut |
623 | =cut |
553 | |
624 | |
554 | our @unblock_queue; |
625 | our @unblock_queue; |
555 | |
626 | |
… | |
… | |
587 | |
658 | |
588 | 1; |
659 | 1; |
589 | |
660 | |
590 | =head1 BUGS/LIMITATIONS |
661 | =head1 BUGS/LIMITATIONS |
591 | |
662 | |
592 | - you must make very sure that no coro is still active on global |
|
|
593 | destruction. very bad things might happen otherwise (usually segfaults). |
|
|
594 | |
|
|
595 | - this module is not thread-safe. You should only ever use this module |
663 | This module is not perl-pseudo-thread-safe. You should only ever use this |
596 | from the same thread (this requirement might be loosened in the future |
664 | module from the same thread (this requirement might be removed in the |
597 | to allow per-thread schedulers, but Coro::State does not yet allow |
665 | future to allow per-thread schedulers, but Coro::State does not yet allow |
598 | this). |
666 | this). I recommend disabling thread support and using processes, as this |
|
|
667 | is much faster and uses less memory. |
599 | |
668 | |
600 | =head1 SEE ALSO |
669 | =head1 SEE ALSO |
601 | |
670 | |
|
|
671 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
|
|
672 | |
|
|
673 | Debugging: L<Coro::Debug>. |
|
|
674 | |
602 | Support/Utility: L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
675 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
603 | |
676 | |
604 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
677 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
605 | |
678 | |
606 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
679 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
607 | |
680 | |
608 | Embedding: L<Coro:MakeMaker> |
681 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
|
|
682 | |
|
|
683 | XS API: L<Coro::MakeMaker>. |
|
|
684 | |
|
|
685 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
609 | |
686 | |
610 | =head1 AUTHOR |
687 | =head1 AUTHOR |
611 | |
688 | |
612 | Marc Lehmann <schmorp@schmorp.de> |
689 | Marc Lehmann <schmorp@schmorp.de> |
613 | http://home.schmorp.de/ |
690 | http://home.schmorp.de/ |