1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | Coro - coroutine process abstraction |
3 | Coro - the real perl threads |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
… | |
… | |
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 |
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21 | use Coro::Semaphore; |
21 | my $lock = new Coro::Semaphore; |
22 | my $lock = new Coro::Semaphore; |
22 | my $locked; |
23 | my $locked; |
23 | |
24 | |
24 | $lock->down; |
25 | $lock->down; |
25 | $locked = 1; |
26 | $locked = 1; |
26 | $lock->up; |
27 | $lock->up; |
27 | |
28 | |
28 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
29 | |
30 | |
30 | This module collection manages coroutines. Coroutines are similar |
31 | This module collection manages coroutines, that is, cooperative |
31 | to threads but don't run in parallel at the same time even on SMP |
32 | threads. Coroutines are similar to kernel threads but don't (in general) |
32 | machines. The specific flavor of coroutine used in this module also |
33 | run in parallel at the same time even on SMP machines. The specific flavor |
33 | guarantees you that it will not switch between coroutines unless |
34 | of coroutine used in this module also guarantees you that it will not |
34 | necessary, at easily-identified points in your program, so locking and |
35 | switch between coroutines unless necessary, at easily-identified points |
35 | parallel access are rarely an issue, making coroutine programming much |
36 | in your program, so locking and parallel access are rarely an issue, |
36 | safer than threads programming. |
37 | making coroutine programming much safer and easier than using other thread |
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38 | models. |
37 | |
39 | |
38 | (Perl, however, does not natively support real threads but instead does a |
40 | Unlike the so-called "Perl threads" (which are not actually real threads |
39 | very slow and memory-intensive emulation of processes using threads. This |
41 | but only the windows process emulation ported to unix), Coro provides a |
40 | is a performance win on Windows machines, and a loss everywhere else). |
42 | full shared address space, which makes communication between coroutines |
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43 | very easy. And coroutines are fast, too: disabling the Windows process |
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44 | emulation code in your perl and using Coro can easily result in a two to |
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45 | four times speed increase for your programs. |
41 | |
46 | |
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47 | Coro achieves that by supporting multiple running interpreters that share |
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48 | data, which is especially useful to code pseudo-parallel processes and |
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49 | for event-based programming, such as multiple HTTP-GET requests running |
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50 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
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51 | into an event-based environment. |
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52 | |
42 | In this module, coroutines are defined as "callchain + lexical variables + |
53 | In this module, a coroutines is defined as "callchain + lexical variables |
43 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
54 | + @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own |
44 | its own set of lexicals and its own set of perls most important global |
55 | callchain, its own set of lexicals and its own set of perls most important |
45 | variables (see L<Coro::State> for more configuration). |
56 | global variables (see L<Coro::State> for more configuration and background |
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57 | info). |
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58 | |
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59 | See also the C<SEE ALSO> section at the end of this document - the Coro |
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60 | module family is quite large. |
46 | |
61 | |
47 | =cut |
62 | =cut |
48 | |
63 | |
49 | package Coro; |
64 | package Coro; |
50 | |
65 | |
51 | use strict; |
66 | use strict qw(vars subs); |
52 | no warnings "uninitialized"; |
67 | no warnings "uninitialized"; |
53 | |
68 | |
54 | use Coro::State; |
69 | use Coro::State; |
55 | |
70 | |
56 | use base qw(Coro::State Exporter); |
71 | use base qw(Coro::State Exporter); |
57 | |
72 | |
58 | our $idle; # idle handler |
73 | our $idle; # idle handler |
59 | our $main; # main coroutine |
74 | our $main; # main coroutine |
60 | our $current; # current coroutine |
75 | our $current; # current coroutine |
61 | |
76 | |
62 | our $VERSION = 4.6; |
77 | our $VERSION = "5.0"; |
63 | |
78 | |
64 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
79 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
65 | our %EXPORT_TAGS = ( |
80 | our %EXPORT_TAGS = ( |
66 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
81 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
67 | ); |
82 | ); |
68 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
83 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
69 | |
84 | |
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85 | =head1 GLOBAL VARIABLES |
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86 | |
70 | =over 4 |
87 | =over 4 |
71 | |
88 | |
72 | =item $main |
89 | =item $Coro::main |
73 | |
90 | |
74 | This coroutine represents the main program. |
91 | This variable stores the coroutine object that represents the main |
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92 | program. While you cna C<ready> it and do most other things you can do to |
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93 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
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94 | whether you are running in the main program or not. |
75 | |
95 | |
76 | =cut |
96 | =cut |
77 | |
97 | |
78 | $main = new Coro; |
98 | # $main is now being initialised by Coro::State |
79 | |
99 | |
80 | =item $current (or as function: current) |
100 | =item $Coro::current |
81 | |
101 | |
82 | The current coroutine (the last coroutine switched to). The initial value |
102 | The coroutine object representing the current coroutine (the last |
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103 | coroutine that the Coro scheduler switched to). The initial value is |
83 | is C<$main> (of course). |
104 | C<$Coro::main> (of course). |
84 | |
105 | |
85 | This variable is B<strictly> I<read-only>. It is provided for performance |
106 | This variable is B<strictly> I<read-only>. You can take copies of the |
86 | reasons. If performance is not essential you are encouraged to use the |
107 | value stored in it and use it as any other coroutine object, but you must |
87 | C<Coro::current> function instead. |
108 | not otherwise modify the variable itself. |
88 | |
109 | |
89 | =cut |
110 | =cut |
90 | |
111 | |
91 | $main->{desc} = "[main::]"; |
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92 | |
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93 | # maybe some other module used Coro::Specific before... |
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94 | $main->{_specific} = $current->{_specific} |
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95 | if $current; |
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96 | |
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97 | _set_current $main; |
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98 | |
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99 | sub current() { $current } |
112 | sub current() { $current } # [DEPRECATED] |
100 | |
113 | |
101 | =item $idle |
114 | =item $Coro::idle |
102 | |
115 | |
103 | 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 |
104 | 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 |
105 | 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. |
106 | |
124 | |
107 | 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 |
108 | 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 |
109 | coroutine so the scheduler can run it. |
127 | coroutine so the scheduler can run it. |
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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. |
110 | |
136 | |
111 | 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 |
112 | handlers), then it must be prepared to be called recursively itself. |
138 | handlers), then it must be prepared to be called recursively itself. |
113 | |
139 | |
114 | =cut |
140 | =cut |
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116 | $idle = sub { |
142 | $idle = sub { |
117 | require Carp; |
143 | require Carp; |
118 | Carp::croak ("FATAL: deadlock detected"); |
144 | Carp::croak ("FATAL: deadlock detected"); |
119 | }; |
145 | }; |
120 | |
146 | |
121 | sub _cancel { |
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122 | my ($self) = @_; |
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123 | |
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124 | # free coroutine data and mark as destructed |
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125 | $self->_destroy |
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126 | or return; |
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127 | |
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128 | # call all destruction callbacks |
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129 | $_->(@{$self->{_status}}) |
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130 | for @{(delete $self->{_on_destroy}) || []}; |
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131 | } |
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132 | |
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133 | # this coroutine is necessary because a coroutine |
147 | # this coroutine is necessary because a coroutine |
134 | # cannot destroy itself. |
148 | # cannot destroy itself. |
135 | my @destroy; |
149 | our @destroy; |
136 | my $manager; |
150 | our $manager; |
137 | |
151 | |
138 | $manager = new Coro sub { |
152 | $manager = new Coro sub { |
139 | while () { |
153 | while () { |
140 | (shift @destroy)->_cancel |
154 | Coro::_cancel shift @destroy |
141 | while @destroy; |
155 | while @destroy; |
142 | |
156 | |
143 | &schedule; |
157 | &schedule; |
144 | } |
158 | } |
145 | }; |
159 | }; |
146 | $manager->desc ("[coro manager]"); |
160 | $manager->{desc} = "[coro manager]"; |
147 | $manager->prio (PRIO_MAX); |
161 | $manager->prio (PRIO_MAX); |
148 | |
162 | |
149 | =back |
163 | =back |
150 | |
164 | |
151 | =head2 STATIC METHODS |
165 | =head1 SIMPLE COROUTINE CREATION |
152 | |
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153 | Static methods are actually functions that operate on the current coroutine only. |
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154 | |
166 | |
155 | =over 4 |
167 | =over 4 |
156 | |
168 | |
157 | =item async { ... } [@args...] |
169 | =item async { ... } [@args...] |
158 | |
170 | |
159 | Create a new asynchronous coroutine and return it's coroutine object |
171 | Create a new coroutine and return it's coroutine object (usually |
160 | (usually unused). When the sub returns the new coroutine is automatically |
172 | unused). The coroutine will be put into the ready queue, so |
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173 | it will start running automatically on the next scheduler run. |
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174 | |
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175 | The first argument is a codeblock/closure that should be executed in the |
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176 | coroutine. When it returns argument returns the coroutine is automatically |
161 | terminated. |
177 | terminated. |
162 | |
178 | |
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179 | The remaining arguments are passed as arguments to the closure. |
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180 | |
163 | See the C<Coro::State::new> constructor for info about the coroutine |
181 | See the C<Coro::State::new> constructor for info about the coroutine |
164 | environment in which coroutines run. |
182 | environment in which coroutines are executed. |
165 | |
183 | |
166 | Calling C<exit> in a coroutine will do the same as calling exit outside |
184 | Calling C<exit> in a coroutine will do the same as calling exit outside |
167 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
185 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
168 | just as it would in the main program. |
186 | just as it would in the main program. |
169 | |
187 | |
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188 | If you do not want that, you can provide a default C<die> handler, or |
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189 | simply avoid dieing (by use of C<eval>). |
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190 | |
170 | # create a new coroutine that just prints its arguments |
191 | Example: Create a new coroutine that just prints its arguments. |
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192 | |
171 | async { |
193 | async { |
172 | print "@_\n"; |
194 | print "@_\n"; |
173 | } 1,2,3,4; |
195 | } 1,2,3,4; |
174 | |
196 | |
175 | =cut |
197 | =cut |
… | |
… | |
181 | } |
203 | } |
182 | |
204 | |
183 | =item async_pool { ... } [@args...] |
205 | =item async_pool { ... } [@args...] |
184 | |
206 | |
185 | Similar to C<async>, but uses a coroutine pool, so you should not call |
207 | Similar to C<async>, but uses a coroutine pool, so you should not call |
186 | terminate or join (although you are allowed to), and you get a coroutine |
208 | terminate or join on it (although you are allowed to), and you get a |
187 | that might have executed other code already (which can be good or bad :). |
209 | coroutine that might have executed other code already (which can be good |
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210 | or bad :). |
188 | |
211 | |
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212 | On the plus side, this function is about twice as fast as creating (and |
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213 | destroying) a completely new coroutine, so if you need a lot of generic |
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214 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
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215 | |
189 | Also, the block is executed in an C<eval> context and a warning will be |
216 | The code block is executed in an C<eval> context and a warning will be |
190 | issued in case of an exception instead of terminating the program, as |
217 | issued in case of an exception instead of terminating the program, as |
191 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
218 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
192 | will not work in the expected way, unless you call terminate or cancel, |
219 | will not work in the expected way, unless you call terminate or cancel, |
193 | which somehow defeats the purpose of pooling. |
220 | which somehow defeats the purpose of pooling (but is fine in the |
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221 | exceptional case). |
194 | |
222 | |
195 | The priority will be reset to C<0> after each job, tracing will be |
223 | The priority will be reset to C<0> after each run, tracing will be |
196 | disabled, the description will be reset and the default output filehandle |
224 | disabled, the description will be reset and the default output filehandle |
197 | gets restored, so you can change alkl these. Otherwise the coroutine will |
225 | gets restored, so you can change all these. Otherwise the coroutine will |
198 | be re-used "as-is": most notably if you change other per-coroutine global |
226 | be re-used "as-is": most notably if you change other per-coroutine global |
199 | stuff such as C<$/> you need to revert that change, which is most simply |
227 | stuff such as C<$/> you I<must needs> revert that change, which is most |
200 | done by using local as in C< local $/ >. |
228 | simply done by using local as in: C<< local $/ >>. |
201 | |
229 | |
202 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
230 | The idle pool size is limited to C<8> idle coroutines (this can be |
203 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
231 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
204 | required. |
232 | coros as required. |
205 | |
233 | |
206 | If you are concerned about pooled coroutines growing a lot because a |
234 | If you are concerned about pooled coroutines growing a lot because a |
207 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
235 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
208 | { terminate }> once per second or so to slowly replenish the pool. In |
236 | { terminate }> once per second or so to slowly replenish the pool. In |
209 | addition to that, when the stacks used by a handler grows larger than 16kb |
237 | addition to that, when the stacks used by a handler grows larger than 32kb |
210 | (adjustable with $Coro::POOL_RSS) it will also exit. |
238 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
211 | |
239 | |
212 | =cut |
240 | =cut |
213 | |
241 | |
214 | our $POOL_SIZE = 8; |
242 | our $POOL_SIZE = 8; |
215 | our $POOL_RSS = 16 * 1024; |
243 | our $POOL_RSS = 32 * 1024; |
216 | our @async_pool; |
244 | our @async_pool; |
217 | |
245 | |
218 | sub pool_handler { |
246 | sub pool_handler { |
219 | my $cb; |
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220 | |
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221 | while () { |
247 | while () { |
222 | eval { |
248 | eval { |
223 | while () { |
249 | &{&_pool_handler} while 1; |
224 | _pool_1 $cb; |
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225 | &$cb; |
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226 | _pool_2 $cb; |
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227 | &schedule; |
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228 | } |
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229 | }; |
250 | }; |
230 | |
251 | |
231 | last if $@ eq "\3async_pool terminate\2\n"; |
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232 | warn $@ if $@; |
252 | warn $@ if $@; |
233 | } |
253 | } |
234 | } |
254 | } |
235 | |
255 | |
236 | sub async_pool(&@) { |
256 | =back |
237 | # this is also inlined into the unlock_scheduler |
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238 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
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239 | |
257 | |
240 | $coro->{_invoke} = [@_]; |
258 | =head1 STATIC METHODS |
241 | $coro->ready; |
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242 | |
259 | |
243 | $coro |
260 | Static methods are actually functions that implicitly operate on the |
244 | } |
261 | current coroutine. |
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262 | |
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263 | =over 4 |
245 | |
264 | |
246 | =item schedule |
265 | =item schedule |
247 | |
266 | |
248 | Calls the scheduler. Please note that the current coroutine will not be put |
267 | Calls the scheduler. The scheduler will find the next coroutine that is |
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268 | to be run from the ready queue and switches to it. The next coroutine |
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269 | to be run is simply the one with the highest priority that is longest |
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270 | in its ready queue. If there is no coroutine ready, it will clal the |
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271 | C<$Coro::idle> hook. |
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272 | |
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273 | Please note that the current coroutine will I<not> be put into the ready |
249 | into the ready queue, so calling this function usually means you will |
274 | queue, so calling this function usually means you will never be called |
250 | never be called again unless something else (e.g. an event handler) calls |
275 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
251 | ready. |
276 | thus waking you up. |
252 | |
277 | |
253 | The canonical way to wait on external events is this: |
278 | This makes C<schedule> I<the> generic method to use to block the current |
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279 | coroutine and wait for events: first you remember the current coroutine in |
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280 | a variable, then arrange for some callback of yours to call C<< ->ready |
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281 | >> on that once some event happens, and last you call C<schedule> to put |
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282 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
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283 | so you need to check whether the event indeed happened, e.g. by storing the |
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284 | status in a variable. |
254 | |
285 | |
255 | { |
286 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
256 | # remember current coroutine |
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257 | my $current = $Coro::current; |
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258 | |
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259 | # register a hypothetical event handler |
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260 | on_event_invoke sub { |
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261 | # wake up sleeping coroutine |
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262 | $current->ready; |
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263 | undef $current; |
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264 | }; |
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265 | |
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266 | # call schedule until event occurred. |
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267 | # in case we are woken up for other reasons |
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268 | # (current still defined), loop. |
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269 | Coro::schedule while $current; |
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270 | } |
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271 | |
287 | |
272 | =item cede |
288 | =item cede |
273 | |
289 | |
274 | "Cede" to other coroutines. This function puts the current coroutine into the |
290 | "Cede" to other coroutines. This function puts the current coroutine into |
275 | ready queue and calls C<schedule>, which has the effect of giving up the |
291 | the ready queue and calls C<schedule>, which has the effect of giving |
276 | current "timeslice" to other coroutines of the same or higher priority. |
292 | up the current "timeslice" to other coroutines of the same or higher |
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293 | priority. Once your coroutine gets its turn again it will automatically be |
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294 | resumed. |
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295 | |
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296 | This function is often called C<yield> in other languages. |
277 | |
297 | |
278 | =item Coro::cede_notself |
298 | =item Coro::cede_notself |
279 | |
299 | |
280 | Works like cede, but is not exported by default and will cede to any |
300 | Works like cede, but is not exported by default and will cede to I<any> |
281 | coroutine, regardless of priority, once. |
301 | coroutine, regardless of priority. This is useful sometimes to ensure |
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302 | progress is made. |
282 | |
303 | |
283 | =item terminate [arg...] |
304 | =item terminate [arg...] |
284 | |
305 | |
285 | Terminates the current coroutine with the given status values (see L<cancel>). |
306 | Terminates the current coroutine with the given status values (see L<cancel>). |
286 | |
307 | |
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288 | |
309 | |
289 | Kills/terminates/cancels all coroutines except the currently running |
310 | Kills/terminates/cancels all coroutines except the currently running |
290 | one. This is useful after a fork, either in the child or the parent, as |
311 | one. This is useful after a fork, either in the child or the parent, as |
291 | usually only one of them should inherit the running coroutines. |
312 | usually only one of them should inherit the running coroutines. |
292 | |
313 | |
293 | =cut |
314 | Note that while this will try to free some of the main programs resources, |
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315 | you cannot free all of them, so if a coroutine that is not the main |
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316 | program calls this function, there will be some one-time resource leak. |
294 | |
317 | |
295 | sub terminate { |
318 | =cut |
296 | $current->cancel (@_); |
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297 | } |
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298 | |
319 | |
299 | sub killall { |
320 | sub killall { |
300 | for (Coro::State::list) { |
321 | for (Coro::State::list) { |
301 | $_->cancel |
322 | $_->cancel |
302 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
323 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
303 | } |
324 | } |
304 | } |
325 | } |
305 | |
326 | |
306 | =back |
327 | =back |
307 | |
328 | |
308 | =head2 COROUTINE METHODS |
329 | =head1 COROUTINE OBJECT METHODS |
309 | |
330 | |
310 | These are the methods you can call on coroutine objects. |
331 | These are the methods you can call on coroutine objects (or to create |
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332 | them). |
311 | |
333 | |
312 | =over 4 |
334 | =over 4 |
313 | |
335 | |
314 | =item new Coro \&sub [, @args...] |
336 | =item new Coro \&sub [, @args...] |
315 | |
337 | |
316 | Create a new coroutine and return it. When the sub returns the coroutine |
338 | Create a new coroutine and return it. When the sub returns, the coroutine |
317 | automatically terminates as if C<terminate> with the returned values were |
339 | automatically terminates as if C<terminate> with the returned values were |
318 | called. To make the coroutine run you must first put it into the ready queue |
340 | called. To make the coroutine run you must first put it into the ready |
319 | by calling the ready method. |
341 | queue by calling the ready method. |
320 | |
342 | |
321 | See C<async> and C<Coro::State::new> for additional info about the |
343 | See C<async> and C<Coro::State::new> for additional info about the |
322 | coroutine environment. |
344 | coroutine environment. |
323 | |
345 | |
324 | =cut |
346 | =cut |
325 | |
347 | |
326 | sub _run_coro { |
348 | sub _terminate { |
327 | terminate &{+shift}; |
349 | terminate &{+shift}; |
328 | } |
350 | } |
329 | |
351 | |
330 | sub new { |
|
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331 | my $class = shift; |
|
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332 | |
|
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333 | $class->SUPER::new (\&_run_coro, @_) |
|
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334 | } |
|
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335 | |
|
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336 | =item $success = $coroutine->ready |
352 | =item $success = $coroutine->ready |
337 | |
353 | |
338 | Put the given coroutine into the ready queue (according to it's priority) |
354 | Put the given coroutine into the end of its ready queue (there is one |
339 | and return true. If the coroutine is already in the ready queue, do nothing |
355 | queue for each priority) and return true. If the coroutine is already in |
340 | and return false. |
356 | the ready queue, do nothing and return false. |
|
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357 | |
|
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358 | This ensures that the scheduler will resume this coroutine automatically |
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359 | once all the coroutines of higher priority and all coroutines of the same |
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360 | priority that were put into the ready queue earlier have been resumed. |
341 | |
361 | |
342 | =item $is_ready = $coroutine->is_ready |
362 | =item $is_ready = $coroutine->is_ready |
343 | |
363 | |
344 | Return wether the coroutine is currently the ready queue or not, |
364 | Return whether the coroutine is currently the ready queue or not, |
345 | |
365 | |
346 | =item $coroutine->cancel (arg...) |
366 | =item $coroutine->cancel (arg...) |
347 | |
367 | |
348 | Terminates the given coroutine and makes it return the given arguments as |
368 | Terminates the given coroutine and makes it return the given arguments as |
349 | status (default: the empty list). Never returns if the coroutine is the |
369 | status (default: the empty list). Never returns if the coroutine is the |
… | |
… | |
351 | |
371 | |
352 | =cut |
372 | =cut |
353 | |
373 | |
354 | sub cancel { |
374 | sub cancel { |
355 | my $self = shift; |
375 | my $self = shift; |
356 | $self->{_status} = [@_]; |
|
|
357 | |
376 | |
358 | if ($current == $self) { |
377 | if ($current == $self) { |
359 | push @destroy, $self; |
378 | terminate @_; |
360 | $manager->ready; |
|
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361 | &schedule while 1; |
|
|
362 | } else { |
379 | } else { |
|
|
380 | $self->{_status} = [@_]; |
363 | $self->_cancel; |
381 | $self->_cancel; |
364 | } |
382 | } |
365 | } |
383 | } |
|
|
384 | |
|
|
385 | =item $coroutine->schedule_to |
|
|
386 | |
|
|
387 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
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388 | of continuing with the next coro from the ready queue, always switch to |
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389 | the given coroutine object (regardless of priority etc.). The readyness |
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390 | state of that coroutine isn't changed. |
|
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391 | |
|
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392 | This is an advanced method for special cases - I'd love to hear about any |
|
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393 | uses for this one. |
|
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394 | |
|
|
395 | =item $coroutine->cede_to |
|
|
396 | |
|
|
397 | Like C<schedule_to>, but puts the current coroutine into the ready |
|
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398 | queue. This has the effect of temporarily switching to the given |
|
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399 | coroutine, and continuing some time later. |
|
|
400 | |
|
|
401 | This is an advanced method for special cases - I'd love to hear about any |
|
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402 | uses for this one. |
|
|
403 | |
|
|
404 | =item $coroutine->throw ([$scalar]) |
|
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405 | |
|
|
406 | If C<$throw> is specified and defined, it will be thrown as an exception |
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407 | inside the coroutine at the next convenient point in time. Otherwise |
|
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408 | clears the exception object. |
|
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409 | |
|
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410 | Coro will check for the exception each time a schedule-like-function |
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411 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
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412 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
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413 | detect this case and return early in case an exception is pending. |
|
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414 | |
|
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415 | The exception object will be thrown "as is" with the specified scalar in |
|
|
416 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
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417 | (unlike with C<die>). |
|
|
418 | |
|
|
419 | This can be used as a softer means than C<cancel> to ask a coroutine to |
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420 | end itself, although there is no guarantee that the exception will lead to |
|
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421 | termination, and if the exception isn't caught it might well end the whole |
|
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422 | program. |
|
|
423 | |
|
|
424 | You might also think of C<throw> as being the moral equivalent of |
|
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425 | C<kill>ing a coroutine with a signal (in this case, a scalar). |
366 | |
426 | |
367 | =item $coroutine->join |
427 | =item $coroutine->join |
368 | |
428 | |
369 | Wait until the coroutine terminates and return any values given to the |
429 | Wait until the coroutine terminates and return any values given to the |
370 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
430 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
371 | from multiple coroutines. |
431 | from multiple coroutines, and all will be resumed and given the status |
|
|
432 | return once the C<$coroutine> terminates. |
372 | |
433 | |
373 | =cut |
434 | =cut |
374 | |
435 | |
375 | sub join { |
436 | sub join { |
376 | my $self = shift; |
437 | my $self = shift; |
… | |
… | |
391 | |
452 | |
392 | =item $coroutine->on_destroy (\&cb) |
453 | =item $coroutine->on_destroy (\&cb) |
393 | |
454 | |
394 | Registers a callback that is called when this coroutine gets destroyed, |
455 | Registers a callback that is called when this coroutine gets destroyed, |
395 | but before it is joined. The callback gets passed the terminate arguments, |
456 | but before it is joined. The callback gets passed the terminate arguments, |
396 | if any. |
457 | if any, and I<must not> die, under any circumstances. |
397 | |
458 | |
398 | =cut |
459 | =cut |
399 | |
460 | |
400 | sub on_destroy { |
461 | sub on_destroy { |
401 | my ($self, $cb) = @_; |
462 | my ($self, $cb) = @_; |
… | |
… | |
431 | higher values mean lower priority, just as in unix). |
492 | higher values mean lower priority, just as in unix). |
432 | |
493 | |
433 | =item $olddesc = $coroutine->desc ($newdesc) |
494 | =item $olddesc = $coroutine->desc ($newdesc) |
434 | |
495 | |
435 | Sets (or gets in case the argument is missing) the description for this |
496 | Sets (or gets in case the argument is missing) the description for this |
436 | coroutine. This is just a free-form string you can associate with a coroutine. |
497 | coroutine. This is just a free-form string you can associate with a |
|
|
498 | coroutine. |
437 | |
499 | |
438 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
500 | This method simply sets the C<< $coroutine->{desc} >> member to the given |
439 | can modify this member directly if you wish. |
501 | string. You can modify this member directly if you wish. |
440 | |
|
|
441 | =item $coroutine->throw ([$scalar]) |
|
|
442 | |
|
|
443 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
444 | inside the coroutine at the next convinient point in time (usually after |
|
|
445 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
446 | exception object. |
|
|
447 | |
|
|
448 | The exception object will be thrown "as is" with the specified scalar in |
|
|
449 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
450 | (unlike with C<die>). |
|
|
451 | |
|
|
452 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
453 | end itself, although there is no guarentee that the exception will lead to |
|
|
454 | termination, and if the exception isn't caught it might well end the whole |
|
|
455 | program. |
|
|
456 | |
502 | |
457 | =cut |
503 | =cut |
458 | |
504 | |
459 | sub desc { |
505 | sub desc { |
460 | my $old = $_[0]{desc}; |
506 | my $old = $_[0]{desc}; |
461 | $_[0]{desc} = $_[1] if @_ > 1; |
507 | $_[0]{desc} = $_[1] if @_ > 1; |
462 | $old; |
508 | $old; |
463 | } |
509 | } |
464 | |
510 | |
|
|
511 | sub transfer { |
|
|
512 | require Carp; |
|
|
513 | Carp::croak ("You must not call ->transfer on Coro objects. Use Coro::State objects or the ->schedule_to method. Caught"); |
|
|
514 | } |
|
|
515 | |
465 | =back |
516 | =back |
466 | |
517 | |
467 | =head2 GLOBAL FUNCTIONS |
518 | =head1 GLOBAL FUNCTIONS |
468 | |
519 | |
469 | =over 4 |
520 | =over 4 |
470 | |
521 | |
471 | =item Coro::nready |
522 | =item Coro::nready |
472 | |
523 | |
473 | Returns the number of coroutines that are currently in the ready state, |
524 | Returns the number of coroutines that are currently in the ready state, |
474 | i.e. that can be switched to. The value C<0> means that the only runnable |
525 | i.e. that can be switched to by calling C<schedule> directory or |
|
|
526 | indirectly. The value C<0> means that the only runnable coroutine is the |
475 | coroutine is the currently running one, so C<cede> would have no effect, |
527 | currently running one, so C<cede> would have no effect, and C<schedule> |
476 | and C<schedule> would cause a deadlock unless there is an idle handler |
528 | would cause a deadlock unless there is an idle handler that wakes up some |
477 | that wakes up some coroutines. |
529 | coroutines. |
478 | |
530 | |
479 | =item my $guard = Coro::guard { ... } |
531 | =item my $guard = Coro::guard { ... } |
480 | |
532 | |
481 | This creates and returns a guard object. Nothing happens until the object |
533 | This creates and returns a guard object. Nothing happens until the object |
482 | gets destroyed, in which case the codeblock given as argument will be |
534 | gets destroyed, in which case the codeblock given as argument will be |
… | |
… | |
511 | |
563 | |
512 | |
564 | |
513 | =item unblock_sub { ... } |
565 | =item unblock_sub { ... } |
514 | |
566 | |
515 | This utility function takes a BLOCK or code reference and "unblocks" it, |
567 | This utility function takes a BLOCK or code reference and "unblocks" it, |
516 | returning the new coderef. This means that the new coderef will return |
568 | returning a new coderef. Unblocking means that calling the new coderef |
517 | immediately without blocking, returning nothing, while the original code |
569 | will return immediately without blocking, returning nothing, while the |
518 | ref will be called (with parameters) from within its own coroutine. |
570 | original code ref will be called (with parameters) from within another |
|
|
571 | coroutine. |
519 | |
572 | |
520 | The reason this function exists is that many event libraries (such as the |
573 | The reason this function exists is that many event libraries (such as the |
521 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
574 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
522 | of thread-safety). This means you must not block within event callbacks, |
575 | of thread-safety). This means you must not block within event callbacks, |
523 | otherwise you might suffer from crashes or worse. |
576 | otherwise you might suffer from crashes or worse. The only event library |
|
|
577 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
524 | |
578 | |
525 | This function allows your callbacks to block by executing them in another |
579 | This function allows your callbacks to block by executing them in another |
526 | coroutine where it is safe to block. One example where blocking is handy |
580 | coroutine where it is safe to block. One example where blocking is handy |
527 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
581 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
528 | disk. |
582 | disk, for example. |
529 | |
583 | |
530 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
584 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
531 | creating event callbacks that want to block. |
585 | creating event callbacks that want to block. |
|
|
586 | |
|
|
587 | If your handler does not plan to block (e.g. simply sends a message to |
|
|
588 | another coroutine, or puts some other coroutine into the ready queue), |
|
|
589 | there is no reason to use C<unblock_sub>. |
|
|
590 | |
|
|
591 | Note that you also need to use C<unblock_sub> for any other callbacks that |
|
|
592 | are indirectly executed by any C-based event loop. For example, when you |
|
|
593 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
|
|
594 | provides callbacks that are the result of some event callback, then you |
|
|
595 | must not block either, or use C<unblock_sub>. |
532 | |
596 | |
533 | =cut |
597 | =cut |
534 | |
598 | |
535 | our @unblock_queue; |
599 | our @unblock_queue; |
536 | |
600 | |
… | |
… | |
539 | # return immediately and can be reused) and because we cannot cede |
603 | # return immediately and can be reused) and because we cannot cede |
540 | # inside an event callback. |
604 | # inside an event callback. |
541 | our $unblock_scheduler = new Coro sub { |
605 | our $unblock_scheduler = new Coro sub { |
542 | while () { |
606 | while () { |
543 | while (my $cb = pop @unblock_queue) { |
607 | while (my $cb = pop @unblock_queue) { |
544 | # this is an inlined copy of async_pool |
608 | &async_pool (@$cb); |
545 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
546 | |
609 | |
547 | $coro->{_invoke} = $cb; |
|
|
548 | $coro->ready; |
|
|
549 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
610 | # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
611 | # as the chance is very high that the async_poll coro will be back |
|
|
612 | # in the idle state when cede returns |
|
|
613 | cede; |
550 | } |
614 | } |
551 | schedule; # sleep well |
615 | schedule; # sleep well |
552 | } |
616 | } |
553 | }; |
617 | }; |
554 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
618 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
555 | |
619 | |
556 | sub unblock_sub(&) { |
620 | sub unblock_sub(&) { |
557 | my $cb = shift; |
621 | my $cb = shift; |
558 | |
622 | |
559 | sub { |
623 | sub { |
560 | unshift @unblock_queue, [$cb, @_]; |
624 | unshift @unblock_queue, [$cb, @_]; |
561 | $unblock_scheduler->ready; |
625 | $unblock_scheduler->ready; |
562 | } |
626 | } |
563 | } |
627 | } |
564 | |
628 | |
|
|
629 | =item $cb = Coro::rouse_cb |
|
|
630 | |
|
|
631 | Create and return a "rouse callback". That's a code reference that, when |
|
|
632 | called, will save its arguments and notify the owner coroutine of the |
|
|
633 | callback. |
|
|
634 | |
|
|
635 | See the next function. |
|
|
636 | |
|
|
637 | =item @args = Coro::rouse_wait [$cb] |
|
|
638 | |
|
|
639 | Wait for the specified rouse callback (or the last one tht was created in |
|
|
640 | this coroutine). |
|
|
641 | |
|
|
642 | As soon as the callback is invoked (or when the calback was invoked before |
|
|
643 | C<rouse_wait>), it will return a copy of the arguments originally passed |
|
|
644 | to the rouse callback. |
|
|
645 | |
|
|
646 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
|
|
647 | |
565 | =back |
648 | =back |
566 | |
649 | |
567 | =cut |
650 | =cut |
568 | |
651 | |
569 | 1; |
652 | 1; |
570 | |
653 | |
|
|
654 | =head1 HOW TO WAIT FOR A CALLBACK |
|
|
655 | |
|
|
656 | It is very common for a coroutine to wait for some callback to be |
|
|
657 | called. This occurs naturally when you use coroutines in an otherwise |
|
|
658 | event-based program, or when you use event-based libraries. |
|
|
659 | |
|
|
660 | These typically register a callback for some event, and call that callback |
|
|
661 | when the event occured. In a coroutine, however, you typically want to |
|
|
662 | just wait for the event, simplyifying things. |
|
|
663 | |
|
|
664 | For example C<< AnyEvent->child >> registers a callback to be called when |
|
|
665 | a specific child has exited: |
|
|
666 | |
|
|
667 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
|
|
668 | |
|
|
669 | But from withina coroutine, you often just want to write this: |
|
|
670 | |
|
|
671 | my $status = wait_for_child $pid; |
|
|
672 | |
|
|
673 | Coro offers two functions specifically designed to make this easy, |
|
|
674 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
|
|
675 | |
|
|
676 | The first function, C<rouse_cb>, generates and returns a callback that, |
|
|
677 | when invoked, will save it's arguments and notify the coroutine that |
|
|
678 | created the callback. |
|
|
679 | |
|
|
680 | The second function, C<rouse_wait>, waits for the callback to be called |
|
|
681 | (by calling C<schedule> to go to sleep) and returns the arguments |
|
|
682 | originally passed to the callback. |
|
|
683 | |
|
|
684 | Using these functions, it becomes easy to write the C<wait_for_child> |
|
|
685 | function mentioned above: |
|
|
686 | |
|
|
687 | sub wait_for_child($) { |
|
|
688 | my ($pid) = @_; |
|
|
689 | |
|
|
690 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
|
|
691 | |
|
|
692 | my ($rpid, $rstatus) = Coro::rouse_wait; |
|
|
693 | $rstatus |
|
|
694 | } |
|
|
695 | |
|
|
696 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
|
|
697 | you can roll your own, using C<schedule>: |
|
|
698 | |
|
|
699 | sub wait_for_child($) { |
|
|
700 | my ($pid) = @_; |
|
|
701 | |
|
|
702 | # store the current coroutine in $current, |
|
|
703 | # and provide result variables for the closure passed to ->child |
|
|
704 | my $current = $Coro::current; |
|
|
705 | my ($done, $rstatus); |
|
|
706 | |
|
|
707 | # pass a closure to ->child |
|
|
708 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
|
|
709 | $rstatus = $_[1]; # remember rstatus |
|
|
710 | $done = 1; # mark $rstatus as valud |
|
|
711 | }); |
|
|
712 | |
|
|
713 | # wait until the closure has been called |
|
|
714 | schedule while !$done; |
|
|
715 | |
|
|
716 | $rstatus |
|
|
717 | } |
|
|
718 | |
|
|
719 | |
571 | =head1 BUGS/LIMITATIONS |
720 | =head1 BUGS/LIMITATIONS |
572 | |
721 | |
573 | - you must make very sure that no coro is still active on global |
722 | =over 4 |
574 | destruction. very bad things might happen otherwise (usually segfaults). |
|
|
575 | |
723 | |
|
|
724 | =item fork with pthread backend |
|
|
725 | |
|
|
726 | When Coro is compiled using the pthread backend (which isn't recommended |
|
|
727 | but required on many BSDs as their libcs are completely broken), then |
|
|
728 | coroutines will not survive a fork. There is no known workaround except to |
|
|
729 | fix your libc and use a saner backend. |
|
|
730 | |
|
|
731 | =item perl process emulation ("threads") |
|
|
732 | |
576 | - this module is not thread-safe. You should only ever use this module |
733 | This module is not perl-pseudo-thread-safe. You should only ever use this |
577 | from the same thread (this requirement might be loosened in the future |
734 | module from the same thread (this requirement might be removed in the |
578 | to allow per-thread schedulers, but Coro::State does not yet allow |
735 | future to allow per-thread schedulers, but Coro::State does not yet allow |
579 | this). |
736 | this). I recommend disabling thread support and using processes, as having |
|
|
737 | the windows process emulation enabled under unix roughly halves perl |
|
|
738 | performance, even when not used. |
|
|
739 | |
|
|
740 | =item coroutine switching not signal safe |
|
|
741 | |
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|
742 | You must not switch to another coroutine from within a signal handler |
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743 | (only relevant with %SIG - most event libraries provide safe signals). |
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744 | |
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745 | That means you I<MUST NOT> call any function that might "block" the |
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746 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
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747 | anything that calls those. Everything else, including calling C<ready>, |
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748 | works. |
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749 | |
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750 | =back |
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751 | |
580 | |
752 | |
581 | =head1 SEE ALSO |
753 | =head1 SEE ALSO |
582 | |
754 | |
583 | Lower level Configuration, Coroutine Environment: L<Coro::State>. |
755 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
584 | |
756 | |
585 | Debugging: L<Coro::Debug>. |
757 | Debugging: L<Coro::Debug>. |
586 | |
758 | |
587 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
759 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
588 | |
760 | |
589 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
761 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
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762 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
590 | |
763 | |
591 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>. |
764 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
592 | |
765 | |
593 | Compatibility: L<Coro::LWP>, L<Coro::Storable>, L<Coro::Select>. |
766 | Compatibility: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
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767 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
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768 | L<Coro::Select>. |
594 | |
769 | |
595 | Embedding: L<Coro::MakeMaker>. |
770 | XS API: L<Coro::MakeMaker>. |
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771 | |
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772 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
596 | |
773 | |
597 | =head1 AUTHOR |
774 | =head1 AUTHOR |
598 | |
775 | |
599 | Marc Lehmann <schmorp@schmorp.de> |
776 | Marc Lehmann <schmorp@schmorp.de> |
600 | http://home.schmorp.de/ |
777 | http://home.schmorp.de/ |