1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | Coro - coroutine process abstraction |
3 | Coro - the only real threads in perl |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
… | |
… | |
11 | print "2\n"; |
11 | print "2\n"; |
12 | cede; # yield back to main |
12 | cede; # yield back to main |
13 | print "4\n"; |
13 | print "4\n"; |
14 | }; |
14 | }; |
15 | print "1\n"; |
15 | print "1\n"; |
16 | cede; # yield to coroutine |
16 | cede; # yield to coro |
17 | print "3\n"; |
17 | print "3\n"; |
18 | cede; # and again |
18 | cede; # and again |
19 | |
19 | |
20 | # use locking |
20 | # use locking |
21 | use Coro::Semaphore; |
21 | use Coro::Semaphore; |
… | |
… | |
26 | $locked = 1; |
26 | $locked = 1; |
27 | $lock->up; |
27 | $lock->up; |
28 | |
28 | |
29 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
30 | |
30 | |
31 | This module collection manages coroutines. Coroutines are similar to |
31 | For a tutorial-style introduction, please read the L<Coro::Intro> |
32 | threads but don't (in general) run in parallel at the same time even |
32 | manpage. This manpage mainly contains reference information. |
33 | on SMP machines. The specific flavor of coroutine used in this module |
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34 | also guarantees you that it will not switch between coroutines unless |
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35 | necessary, at easily-identified points in your program, so locking and |
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36 | parallel access are rarely an issue, making coroutine programming much |
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37 | safer and easier than threads programming. |
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38 | |
33 | |
39 | Unlike a normal perl program, however, coroutines allow you to have |
34 | This module collection manages continuations in general, most often in |
40 | multiple running interpreters that share data, which is especially useful |
35 | the form of cooperative threads (also called coros, or simply "coro" |
41 | to code pseudo-parallel processes and for event-based programming, such as |
36 | in the documentation). They are similar to kernel threads but don't (in |
42 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
37 | general) run in parallel at the same time even on SMP machines. The |
43 | learn more. |
38 | specific flavor of thread offered by this module also guarantees you that |
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39 | it will not switch between threads unless necessary, at easily-identified |
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40 | points in your program, so locking and parallel access are rarely an |
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41 | issue, making thread programming much safer and easier than using other |
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42 | thread models. |
44 | |
43 | |
45 | Coroutines are also useful because Perl has no support for threads (the so |
44 | Unlike the so-called "Perl threads" (which are not actually real threads |
46 | called "threads" that perl offers are nothing more than the (bad) process |
45 | but only the windows process emulation ported to unix), Coro provides a |
47 | emulation coming from the Windows platform: On standard operating systems |
46 | full shared address space, which makes communication between threads |
48 | they serve no purpose whatsoever, except by making your programs slow and |
47 | very easy. And threads are fast, too: disabling the Windows process |
49 | making them use a lot of memory. Best disable them when building perl, or |
48 | emulation code in your perl and using Coro can easily result in a two to |
50 | aks your software vendor/distributor to do it for you). |
49 | four times speed increase for your programs. |
51 | |
50 | |
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51 | Coro achieves that by supporting multiple running interpreters that share |
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52 | data, which is especially useful to code pseudo-parallel processes and |
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53 | for event-based programming, such as multiple HTTP-GET requests running |
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54 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
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55 | into an event-based environment. |
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56 | |
52 | In this module, coroutines are defined as "callchain + lexical variables + |
57 | In this module, a thread is defined as "callchain + lexical variables + |
53 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
58 | @_ + $_ + $@ + $/ + C stack), that is, a thread has its own callchain, |
54 | its own set of lexicals and its own set of perls most important global |
59 | its own set of lexicals and its own set of perls most important global |
55 | variables (see L<Coro::State> for more configuration). |
60 | variables (see L<Coro::State> for more configuration and background info). |
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61 | |
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62 | See also the C<SEE ALSO> section at the end of this document - the Coro |
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63 | module family is quite large. |
56 | |
64 | |
57 | =cut |
65 | =cut |
58 | |
66 | |
59 | package Coro; |
67 | package Coro; |
60 | |
68 | |
61 | use strict; |
69 | use strict qw(vars subs); |
62 | no warnings "uninitialized"; |
70 | no warnings "uninitialized"; |
63 | |
71 | |
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72 | use Guard (); |
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73 | |
64 | use Coro::State; |
74 | use Coro::State; |
65 | |
75 | |
66 | use base qw(Coro::State Exporter); |
76 | use base qw(Coro::State Exporter); |
67 | |
77 | |
68 | our $idle; # idle handler |
78 | our $idle; # idle handler |
69 | our $main; # main coroutine |
79 | our $main; # main coro |
70 | our $current; # current coroutine |
80 | our $current; # current coro |
71 | |
81 | |
72 | our $VERSION = 4.801; |
82 | our $VERSION = 5.13; |
73 | |
83 | |
74 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
84 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
75 | our %EXPORT_TAGS = ( |
85 | our %EXPORT_TAGS = ( |
76 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
86 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
77 | ); |
87 | ); |
78 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
88 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
79 | |
89 | |
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90 | =head1 GLOBAL VARIABLES |
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91 | |
80 | =over 4 |
92 | =over 4 |
81 | |
93 | |
82 | =item $Coro::main |
94 | =item $Coro::main |
83 | |
95 | |
84 | This variable stores the coroutine object that represents the main |
96 | This variable stores the Coro object that represents the main |
85 | program. While you cna C<ready> it and do most other things you can do to |
97 | program. While you cna C<ready> it and do most other things you can do to |
86 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
98 | coro, it is mainly useful to compare again C<$Coro::current>, to see |
87 | whether you are running in the main program or not. |
99 | whether you are running in the main program or not. |
88 | |
100 | |
89 | =cut |
101 | =cut |
90 | |
102 | |
91 | $main = new Coro; |
103 | # $main is now being initialised by Coro::State |
92 | |
104 | |
93 | =item $Coro::current |
105 | =item $Coro::current |
94 | |
106 | |
95 | The coroutine object representing the current coroutine (the last |
107 | The Coro object representing the current coro (the last |
96 | coroutine that the Coro scheduler switched to). The initial value is |
108 | coro that the Coro scheduler switched to). The initial value is |
97 | C<$main> (of course). |
109 | C<$Coro::main> (of course). |
98 | |
110 | |
99 | This variable is B<strictly> I<read-only>. You can take copies of the |
111 | This variable is B<strictly> I<read-only>. You can take copies of the |
100 | value stored in it and use it as any other coroutine object, but you must |
112 | value stored in it and use it as any other Coro object, but you must |
101 | not otherwise modify the variable itself. |
113 | not otherwise modify the variable itself. |
102 | |
114 | |
103 | =cut |
115 | =cut |
104 | |
116 | |
105 | $main->{desc} = "[main::]"; |
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106 | |
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107 | # maybe some other module used Coro::Specific before... |
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108 | $main->{_specific} = $current->{_specific} |
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109 | if $current; |
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110 | |
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111 | _set_current $main; |
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112 | |
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113 | sub current() { $current } # [DEPRECATED] |
117 | sub current() { $current } # [DEPRECATED] |
114 | |
118 | |
115 | =item $Coro::idle |
119 | =item $Coro::idle |
116 | |
120 | |
117 | This variable is mainly useful to integrate Coro into event loops. It is |
121 | This variable is mainly useful to integrate Coro into event loops. It is |
118 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
122 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
119 | pretty low-level functionality. |
123 | pretty low-level functionality. |
120 | |
124 | |
121 | This variable stores a callback that is called whenever the scheduler |
125 | This variable stores either a Coro object or a callback. |
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126 | |
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127 | If it is a callback, the it is called whenever the scheduler finds no |
122 | finds no ready coroutines to run. The default implementation prints |
128 | ready coros to run. The default implementation prints "FATAL: |
123 | "FATAL: deadlock detected" and exits, because the program has no other way |
129 | deadlock detected" and exits, because the program has no other way to |
124 | to continue. |
130 | continue. |
125 | |
131 | |
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132 | If it is a coro object, then this object will be readied (without |
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133 | invoking any ready hooks, however) when the scheduler finds no other ready |
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134 | coros to run. |
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135 | |
126 | This hook is overwritten by modules such as C<Coro::Timer> and |
136 | This hook is overwritten by modules such as C<Coro::EV> and |
127 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
137 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
128 | coroutine so the scheduler can run it. |
138 | coro so the scheduler can run it. |
129 | |
139 | |
130 | Note that the callback I<must not>, under any circumstances, block |
140 | Note that the callback I<must not>, under any circumstances, block |
131 | the current coroutine. Normally, this is achieved by having an "idle |
141 | the current coro. Normally, this is achieved by having an "idle |
132 | coroutine" that calls the event loop and then blocks again, and then |
142 | coro" that calls the event loop and then blocks again, and then |
133 | readying that coroutine in the idle handler. |
143 | readying that coro in the idle handler, or by simply placing the idle |
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144 | coro in this variable. |
134 | |
145 | |
135 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
146 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
136 | technique. |
147 | technique. |
137 | |
148 | |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
149 | Please note that if your callback recursively invokes perl (e.g. for event |
… | |
… | |
143 | $idle = sub { |
154 | $idle = sub { |
144 | require Carp; |
155 | require Carp; |
145 | Carp::croak ("FATAL: deadlock detected"); |
156 | Carp::croak ("FATAL: deadlock detected"); |
146 | }; |
157 | }; |
147 | |
158 | |
148 | sub _cancel { |
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149 | my ($self) = @_; |
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150 | |
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151 | # free coroutine data and mark as destructed |
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152 | $self->_destroy |
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153 | or return; |
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154 | |
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155 | # call all destruction callbacks |
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156 | $_->(@{$self->{_status}}) |
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157 | for @{(delete $self->{_on_destroy}) || []}; |
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158 | } |
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159 | |
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160 | # this coroutine is necessary because a coroutine |
159 | # this coro is necessary because a coro |
161 | # cannot destroy itself. |
160 | # cannot destroy itself. |
162 | my @destroy; |
161 | our @destroy; |
163 | my $manager; |
162 | our $manager; |
164 | |
163 | |
165 | $manager = new Coro sub { |
164 | $manager = new Coro sub { |
166 | while () { |
165 | while () { |
167 | (shift @destroy)->_cancel |
166 | Coro::State::cancel shift @destroy |
168 | while @destroy; |
167 | while @destroy; |
169 | |
168 | |
170 | &schedule; |
169 | &schedule; |
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 | =back |
175 | =back |
177 | |
176 | |
178 | =head2 SIMPLE COROUTINE CREATION |
177 | =head1 SIMPLE CORO CREATION |
179 | |
178 | |
180 | =over 4 |
179 | =over 4 |
181 | |
180 | |
182 | =item async { ... } [@args...] |
181 | =item async { ... } [@args...] |
183 | |
182 | |
184 | Create a new coroutine and return it's coroutine object (usually |
183 | Create a new coro and return its Coro object (usually |
185 | unused). The coroutine will be put into the ready queue, so |
184 | unused). The coro will be put into the ready queue, so |
186 | it will start running automatically on the next scheduler run. |
185 | it will start running automatically on the next scheduler run. |
187 | |
186 | |
188 | The first argument is a codeblock/closure that should be executed in the |
187 | The first argument is a codeblock/closure that should be executed in the |
189 | coroutine. When it returns argument returns the coroutine is automatically |
188 | coro. When it returns argument returns the coro is automatically |
190 | terminated. |
189 | terminated. |
191 | |
190 | |
192 | The remaining arguments are passed as arguments to the closure. |
191 | The remaining arguments are passed as arguments to the closure. |
193 | |
192 | |
194 | See the C<Coro::State::new> constructor for info about the coroutine |
193 | See the C<Coro::State::new> constructor for info about the coro |
195 | environment in which coroutines are executed. |
194 | environment in which coro are executed. |
196 | |
195 | |
197 | Calling C<exit> in a coroutine will do the same as calling exit outside |
196 | Calling C<exit> in a coro will do the same as calling exit outside |
198 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
197 | the coro. Likewise, when the coro dies, the program will exit, |
199 | just as it would in the main program. |
198 | just as it would in the main program. |
200 | |
199 | |
201 | If you do not want that, you can provide a default C<die> handler, or |
200 | If you do not want that, you can provide a default C<die> handler, or |
202 | simply avoid dieing (by use of C<eval>). |
201 | simply avoid dieing (by use of C<eval>). |
203 | |
202 | |
204 | Example: Create a new coroutine that just prints its arguments. |
203 | Example: Create a new coro that just prints its arguments. |
205 | |
204 | |
206 | async { |
205 | async { |
207 | print "@_\n"; |
206 | print "@_\n"; |
208 | } 1,2,3,4; |
207 | } 1,2,3,4; |
209 | |
208 | |
… | |
… | |
215 | $coro |
214 | $coro |
216 | } |
215 | } |
217 | |
216 | |
218 | =item async_pool { ... } [@args...] |
217 | =item async_pool { ... } [@args...] |
219 | |
218 | |
220 | Similar to C<async>, but uses a coroutine pool, so you should not call |
219 | Similar to C<async>, but uses a coro pool, so you should not call |
221 | terminate or join on it (although you are allowed to), and you get a |
220 | terminate or join on it (although you are allowed to), and you get a |
222 | coroutine that might have executed other code already (which can be good |
221 | coro that might have executed other code already (which can be good |
223 | or bad :). |
222 | or bad :). |
224 | |
223 | |
225 | On the plus side, this function is faster than creating (and destroying) |
224 | On the plus side, this function is about twice as fast as creating (and |
226 | a completly new coroutine, so if you need a lot of generic coroutines in |
225 | destroying) a completely new coro, so if you need a lot of generic |
227 | quick successsion, use C<async_pool>, not C<async>. |
226 | coros in quick successsion, use C<async_pool>, not C<async>. |
228 | |
227 | |
229 | The code 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 |
230 | 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 |
231 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
230 | C<async> does. As the coro is being reused, stuff like C<on_destroy> |
232 | 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, |
233 | which somehow defeats the purpose of pooling (but is fine in the |
232 | which somehow defeats the purpose of pooling (but is fine in the |
234 | exceptional case). |
233 | exceptional case). |
235 | |
234 | |
236 | The priority will be reset to C<0> after each run, tracing will be |
235 | The priority will be reset to C<0> after each run, tracing will be |
237 | disabled, the description will be reset and the default output filehandle |
236 | disabled, the description will be reset and the default output filehandle |
238 | gets restored, so you can change all these. Otherwise the coroutine will |
237 | gets restored, so you can change all these. Otherwise the coro will |
239 | 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-coro global |
240 | stuff such as C<$/> you I<must needs> revert that change, which is most |
239 | stuff such as C<$/> you I<must needs> revert that change, which is most |
241 | simply done by using local as in: C<< local $/ >>. |
240 | simply done by using local as in: C<< local $/ >>. |
242 | |
241 | |
243 | The idle pool size is limited to C<8> idle coroutines (this can be |
242 | The idle pool size is limited to C<8> idle coros (this can be |
244 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
243 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
245 | coros as required. |
244 | coros as required. |
246 | |
245 | |
247 | If you are concerned about pooled coroutines growing a lot because a |
246 | If you are concerned about pooled coros growing a lot because a |
248 | 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 |
249 | { 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 |
250 | 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 32kb |
251 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
250 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
252 | |
251 | |
253 | =cut |
252 | =cut |
254 | |
253 | |
255 | our $POOL_SIZE = 8; |
254 | our $POOL_SIZE = 8; |
256 | our $POOL_RSS = 16 * 1024; |
255 | our $POOL_RSS = 32 * 1024; |
257 | our @async_pool; |
256 | our @async_pool; |
258 | |
257 | |
259 | sub pool_handler { |
258 | sub pool_handler { |
260 | my $cb; |
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261 | |
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262 | while () { |
259 | while () { |
263 | eval { |
260 | eval { |
264 | while () { |
261 | &{&_pool_handler} while 1; |
265 | _pool_1 $cb; |
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266 | &$cb; |
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267 | _pool_2 $cb; |
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268 | &schedule; |
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269 | } |
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270 | }; |
262 | }; |
271 | |
263 | |
272 | if ($@) { |
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273 | last if $@ eq "\3async_pool terminate\2\n"; |
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274 | warn $@; |
264 | warn $@ if $@; |
275 | } |
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276 | } |
265 | } |
277 | } |
266 | } |
278 | |
267 | |
279 | sub async_pool(&@) { |
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280 | # this is also inlined into the unlock_scheduler |
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281 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
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282 | |
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283 | $coro->{_invoke} = [@_]; |
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284 | $coro->ready; |
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285 | |
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286 | $coro |
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287 | } |
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288 | |
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289 | =back |
268 | =back |
290 | |
269 | |
291 | =head2 STATIC METHODS |
270 | =head1 STATIC METHODS |
292 | |
271 | |
293 | Static methods are actually functions that operate on the current coroutine. |
272 | Static methods are actually functions that implicitly operate on the |
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273 | current coro. |
294 | |
274 | |
295 | =over 4 |
275 | =over 4 |
296 | |
276 | |
297 | =item schedule |
277 | =item schedule |
298 | |
278 | |
299 | Calls the scheduler. The scheduler will find the next coroutine that is |
279 | Calls the scheduler. The scheduler will find the next coro that is |
300 | to be run from the ready queue and switches to it. The next coroutine |
280 | to be run from the ready queue and switches to it. The next coro |
301 | to be run is simply the one with the highest priority that is longest |
281 | to be run is simply the one with the highest priority that is longest |
302 | in its ready queue. If there is no coroutine ready, it will clal the |
282 | in its ready queue. If there is no coro ready, it will clal the |
303 | C<$Coro::idle> hook. |
283 | C<$Coro::idle> hook. |
304 | |
284 | |
305 | Please note that the current coroutine will I<not> be put into the ready |
285 | Please note that the current coro will I<not> be put into the ready |
306 | queue, so calling this function usually means you will never be called |
286 | queue, so calling this function usually means you will never be called |
307 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
287 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
308 | thus waking you up. |
288 | thus waking you up. |
309 | |
289 | |
310 | This makes C<schedule> I<the> generic method to use to block the current |
290 | This makes C<schedule> I<the> generic method to use to block the current |
311 | coroutine and wait for events: first you remember the current coroutine in |
291 | coro and wait for events: first you remember the current coro in |
312 | a variable, then arrange for some callback of yours to call C<< ->ready |
292 | a variable, then arrange for some callback of yours to call C<< ->ready |
313 | >> on that once some event happens, and last you call C<schedule> to put |
293 | >> on that once some event happens, and last you call C<schedule> to put |
314 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
294 | yourself to sleep. Note that a lot of things can wake your coro up, |
315 | so you need to check whether the event indeed happened, e.g. by storing the |
295 | so you need to check whether the event indeed happened, e.g. by storing the |
316 | status in a variable. |
296 | status in a variable. |
317 | |
297 | |
318 | The canonical way to wait on external events is this: |
298 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
319 | |
299 | |
320 | { |
300 | =item cede |
321 | # remember current coroutine |
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322 | my $current = $Coro::current; |
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323 | |
301 | |
324 | # register a hypothetical event handler |
302 | "Cede" to other coros. This function puts the current coro into |
325 | on_event_invoke sub { |
303 | the ready queue and calls C<schedule>, which has the effect of giving |
326 | # wake up sleeping coroutine |
304 | up the current "timeslice" to other coros of the same or higher |
327 | $current->ready; |
305 | priority. Once your coro gets its turn again it will automatically be |
328 | undef $current; |
306 | resumed. |
|
|
307 | |
|
|
308 | This function is often called C<yield> in other languages. |
|
|
309 | |
|
|
310 | =item Coro::cede_notself |
|
|
311 | |
|
|
312 | Works like cede, but is not exported by default and will cede to I<any> |
|
|
313 | coro, regardless of priority. This is useful sometimes to ensure |
|
|
314 | progress is made. |
|
|
315 | |
|
|
316 | =item terminate [arg...] |
|
|
317 | |
|
|
318 | Terminates the current coro with the given status values (see L<cancel>). |
|
|
319 | |
|
|
320 | =item Coro::on_enter BLOCK, Coro::on_leave BLOCK |
|
|
321 | |
|
|
322 | These function install enter and leave winders in the current scope. The |
|
|
323 | enter block will be executed when on_enter is called and whenever the |
|
|
324 | current coro is re-entered by the scheduler, while the leave block is |
|
|
325 | executed whenever the current coro is blocked by the scheduler, and |
|
|
326 | also when the containing scope is exited (by whatever means, be it exit, |
|
|
327 | die, last etc.). |
|
|
328 | |
|
|
329 | I<Neither invoking the scheduler, nor exceptions, are allowed within those |
|
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330 | BLOCKs>. That means: do not even think about calling C<die> without an |
|
|
331 | eval, and do not even think of entering the scheduler in any way. |
|
|
332 | |
|
|
333 | Since both BLOCKs are tied to the current scope, they will automatically |
|
|
334 | be removed when the current scope exits. |
|
|
335 | |
|
|
336 | These functions implement the same concept as C<dynamic-wind> in scheme |
|
|
337 | does, and are useful when you want to localise some resource to a specific |
|
|
338 | coro. |
|
|
339 | |
|
|
340 | They slow down coro switching considerably for coros that use |
|
|
341 | them (But coro switching is still reasonably fast if the handlers are |
|
|
342 | fast). |
|
|
343 | |
|
|
344 | These functions are best understood by an example: The following function |
|
|
345 | will change the current timezone to "Antarctica/South_Pole", which |
|
|
346 | requires a call to C<tzset>, but by using C<on_enter> and C<on_leave>, |
|
|
347 | which remember/change the current timezone and restore the previous |
|
|
348 | value, respectively, the timezone is only changes for the coro that |
|
|
349 | installed those handlers. |
|
|
350 | |
|
|
351 | use POSIX qw(tzset); |
|
|
352 | |
|
|
353 | async { |
|
|
354 | my $old_tz; # store outside TZ value here |
|
|
355 | |
|
|
356 | Coro::on_enter { |
|
|
357 | $old_tz = $ENV{TZ}; # remember the old value |
|
|
358 | |
|
|
359 | $ENV{TZ} = "Antarctica/South_Pole"; |
|
|
360 | tzset; # enable new value |
329 | }; |
361 | }; |
330 | |
362 | |
331 | # call schedule until event occurred. |
363 | Coro::on_leave { |
332 | # in case we are woken up for other reasons |
364 | $ENV{TZ} = $old_tz; |
333 | # (current still defined), loop. |
365 | tzset; # restore old value |
334 | Coro::schedule while $current; |
366 | }; |
|
|
367 | |
|
|
368 | # at this place, the timezone is Antarctica/South_Pole, |
|
|
369 | # without disturbing the TZ of any other coro. |
335 | } |
370 | }; |
336 | |
371 | |
337 | =item cede |
372 | This can be used to localise about any resource (locale, uid, current |
338 | |
373 | working directory etc.) to a block, despite the existance of other |
339 | "Cede" to other coroutines. This function puts the current coroutine into |
374 | coros. |
340 | the ready queue and calls C<schedule>, which has the effect of giving |
|
|
341 | up the current "timeslice" to other coroutines of the same or higher |
|
|
342 | priority. Once your coroutine gets its turn again it will automatically be |
|
|
343 | resumed. |
|
|
344 | |
|
|
345 | This function is often called C<yield> in other languages. |
|
|
346 | |
|
|
347 | =item Coro::cede_notself |
|
|
348 | |
|
|
349 | Works like cede, but is not exported by default and will cede to I<any> |
|
|
350 | coroutine, regardless of priority. This is useful sometimes to ensure |
|
|
351 | progress is made. |
|
|
352 | |
|
|
353 | =item terminate [arg...] |
|
|
354 | |
|
|
355 | Terminates the current coroutine with the given status values (see L<cancel>). |
|
|
356 | |
375 | |
357 | =item killall |
376 | =item killall |
358 | |
377 | |
359 | Kills/terminates/cancels all coroutines except the currently running |
378 | Kills/terminates/cancels all coros except the currently running one. |
360 | one. This is useful after a fork, either in the child or the parent, as |
|
|
361 | usually only one of them should inherit the running coroutines. |
|
|
362 | |
379 | |
363 | Note that while this will try to free some of the main programs resources, |
380 | Note that while this will try to free some of the main interpreter |
|
|
381 | resources if the calling coro isn't the main coro, but one |
364 | you cannot free all of them, so if a coroutine that is not the main |
382 | cannot free all of them, so if a coro that is not the main coro |
365 | program calls this function, there will be some one-time resource leak. |
383 | calls this function, there will be some one-time resource leak. |
366 | |
384 | |
367 | =cut |
385 | =cut |
368 | |
|
|
369 | sub terminate { |
|
|
370 | $current->cancel (@_); |
|
|
371 | } |
|
|
372 | |
386 | |
373 | sub killall { |
387 | sub killall { |
374 | for (Coro::State::list) { |
388 | for (Coro::State::list) { |
375 | $_->cancel |
389 | $_->cancel |
376 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
390 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
377 | } |
391 | } |
378 | } |
392 | } |
379 | |
393 | |
380 | =back |
394 | =back |
381 | |
395 | |
382 | =head2 COROUTINE METHODS |
396 | =head1 CORO OBJECT METHODS |
383 | |
397 | |
384 | These are the methods you can call on coroutine objects (or to create |
398 | These are the methods you can call on coro objects (or to create |
385 | them). |
399 | them). |
386 | |
400 | |
387 | =over 4 |
401 | =over 4 |
388 | |
402 | |
389 | =item new Coro \&sub [, @args...] |
403 | =item new Coro \&sub [, @args...] |
390 | |
404 | |
391 | Create a new coroutine and return it. When the sub returns, the coroutine |
405 | Create a new coro and return it. When the sub returns, the coro |
392 | automatically terminates as if C<terminate> with the returned values were |
406 | automatically terminates as if C<terminate> with the returned values were |
393 | called. To make the coroutine run you must first put it into the ready |
407 | called. To make the coro run you must first put it into the ready |
394 | queue by calling the ready method. |
408 | queue by calling the ready method. |
395 | |
409 | |
396 | See C<async> and C<Coro::State::new> for additional info about the |
410 | See C<async> and C<Coro::State::new> for additional info about the |
397 | coroutine environment. |
411 | coro environment. |
398 | |
412 | |
399 | =cut |
413 | =cut |
400 | |
414 | |
401 | sub _run_coro { |
415 | sub _coro_run { |
402 | terminate &{+shift}; |
416 | terminate &{+shift}; |
403 | } |
417 | } |
404 | |
418 | |
405 | sub new { |
|
|
406 | my $class = shift; |
|
|
407 | |
|
|
408 | $class->SUPER::new (\&_run_coro, @_) |
|
|
409 | } |
|
|
410 | |
|
|
411 | =item $success = $coroutine->ready |
419 | =item $success = $coro->ready |
412 | |
420 | |
413 | Put the given coroutine into the end of its ready queue (there is one |
421 | Put the given coro into the end of its ready queue (there is one |
414 | queue for each priority) and return true. If the coroutine is already in |
422 | queue for each priority) and return true. If the coro is already in |
415 | the ready queue, do nothing and return false. |
423 | the ready queue, do nothing and return false. |
416 | |
424 | |
417 | This ensures that the scheduler will resume this coroutine automatically |
425 | This ensures that the scheduler will resume this coro automatically |
418 | once all the coroutines of higher priority and all coroutines of the same |
426 | once all the coro of higher priority and all coro of the same |
419 | priority that were put into the ready queue earlier have been resumed. |
427 | priority that were put into the ready queue earlier have been resumed. |
420 | |
428 | |
421 | =item $is_ready = $coroutine->is_ready |
429 | =item $is_ready = $coro->is_ready |
422 | |
430 | |
423 | Return whether the coroutine is currently the ready queue or not, |
431 | Returns true iff the Coro object is in the ready queue. Unless the Coro |
|
|
432 | object gets destroyed, it will eventually be scheduled by the scheduler. |
424 | |
433 | |
|
|
434 | =item $is_running = $coro->is_running |
|
|
435 | |
|
|
436 | Returns true iff the Coro object is currently running. Only one Coro object |
|
|
437 | can ever be in the running state (but it currently is possible to have |
|
|
438 | multiple running Coro::States). |
|
|
439 | |
|
|
440 | =item $is_suspended = $coro->is_suspended |
|
|
441 | |
|
|
442 | Returns true iff this Coro object has been suspended. Suspended Coros will |
|
|
443 | not ever be scheduled. |
|
|
444 | |
425 | =item $coroutine->cancel (arg...) |
445 | =item $coro->cancel (arg...) |
426 | |
446 | |
427 | Terminates the given coroutine and makes it return the given arguments as |
447 | Terminates the given Coro and makes it return the given arguments as |
428 | status (default: the empty list). Never returns if the coroutine is the |
448 | status (default: the empty list). Never returns if the Coro is the |
429 | current coroutine. |
449 | current Coro. |
430 | |
450 | |
431 | =cut |
451 | =cut |
432 | |
452 | |
433 | sub cancel { |
453 | sub cancel { |
434 | my $self = shift; |
454 | my $self = shift; |
435 | $self->{_status} = [@_]; |
|
|
436 | |
455 | |
437 | if ($current == $self) { |
456 | if ($current == $self) { |
438 | push @destroy, $self; |
457 | terminate @_; |
439 | $manager->ready; |
|
|
440 | &schedule while 1; |
|
|
441 | } else { |
458 | } else { |
442 | $self->_cancel; |
459 | $self->{_status} = [@_]; |
|
|
460 | Coro::State::cancel $self; |
443 | } |
461 | } |
444 | } |
462 | } |
445 | |
463 | |
|
|
464 | =item $coro->schedule_to |
|
|
465 | |
|
|
466 | Puts the current coro to sleep (like C<Coro::schedule>), but instead |
|
|
467 | of continuing with the next coro from the ready queue, always switch to |
|
|
468 | the given coro object (regardless of priority etc.). The readyness |
|
|
469 | state of that coro isn't changed. |
|
|
470 | |
|
|
471 | This is an advanced method for special cases - I'd love to hear about any |
|
|
472 | uses for this one. |
|
|
473 | |
|
|
474 | =item $coro->cede_to |
|
|
475 | |
|
|
476 | Like C<schedule_to>, but puts the current coro into the ready |
|
|
477 | queue. This has the effect of temporarily switching to the given |
|
|
478 | coro, and continuing some time later. |
|
|
479 | |
|
|
480 | This is an advanced method for special cases - I'd love to hear about any |
|
|
481 | uses for this one. |
|
|
482 | |
|
|
483 | =item $coro->throw ([$scalar]) |
|
|
484 | |
|
|
485 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
486 | inside the coro at the next convenient point in time. Otherwise |
|
|
487 | clears the exception object. |
|
|
488 | |
|
|
489 | Coro will check for the exception each time a schedule-like-function |
|
|
490 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
|
|
491 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
|
|
492 | detect this case and return early in case an exception is pending. |
|
|
493 | |
|
|
494 | The exception object will be thrown "as is" with the specified scalar in |
|
|
495 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
496 | (unlike with C<die>). |
|
|
497 | |
|
|
498 | This can be used as a softer means than C<cancel> to ask a coro to |
|
|
499 | end itself, although there is no guarantee that the exception will lead to |
|
|
500 | termination, and if the exception isn't caught it might well end the whole |
|
|
501 | program. |
|
|
502 | |
|
|
503 | You might also think of C<throw> as being the moral equivalent of |
|
|
504 | C<kill>ing a coro with a signal (in this case, a scalar). |
|
|
505 | |
446 | =item $coroutine->join |
506 | =item $coro->join |
447 | |
507 | |
448 | Wait until the coroutine terminates and return any values given to the |
508 | Wait until the coro terminates and return any values given to the |
449 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
509 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
450 | from multiple coroutines, and all will be resumed and given the status |
510 | from multiple coro, and all will be resumed and given the status |
451 | return once the C<$coroutine> terminates. |
511 | return once the C<$coro> terminates. |
452 | |
512 | |
453 | =cut |
513 | =cut |
454 | |
514 | |
455 | sub join { |
515 | sub join { |
456 | my $self = shift; |
516 | my $self = shift; |
… | |
… | |
467 | } |
527 | } |
468 | |
528 | |
469 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
529 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
470 | } |
530 | } |
471 | |
531 | |
472 | =item $coroutine->on_destroy (\&cb) |
532 | =item $coro->on_destroy (\&cb) |
473 | |
533 | |
474 | Registers a callback that is called when this coroutine gets destroyed, |
534 | Registers a callback that is called when this coro gets destroyed, |
475 | but before it is joined. The callback gets passed the terminate arguments, |
535 | but before it is joined. The callback gets passed the terminate arguments, |
476 | if any, and I<must not> die, under any circumstances. |
536 | if any, and I<must not> die, under any circumstances. |
477 | |
537 | |
478 | =cut |
538 | =cut |
479 | |
539 | |
… | |
… | |
481 | my ($self, $cb) = @_; |
541 | my ($self, $cb) = @_; |
482 | |
542 | |
483 | push @{ $self->{_on_destroy} }, $cb; |
543 | push @{ $self->{_on_destroy} }, $cb; |
484 | } |
544 | } |
485 | |
545 | |
486 | =item $oldprio = $coroutine->prio ($newprio) |
546 | =item $oldprio = $coro->prio ($newprio) |
487 | |
547 | |
488 | Sets (or gets, if the argument is missing) the priority of the |
548 | Sets (or gets, if the argument is missing) the priority of the |
489 | coroutine. Higher priority coroutines get run before lower priority |
549 | coro. Higher priority coro get run before lower priority |
490 | coroutines. Priorities are small signed integers (currently -4 .. +3), |
550 | coro. Priorities are small signed integers (currently -4 .. +3), |
491 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
551 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
492 | to get then): |
552 | to get then): |
493 | |
553 | |
494 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
554 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
495 | 3 > 1 > 0 > -1 > -3 > -4 |
555 | 3 > 1 > 0 > -1 > -3 > -4 |
496 | |
556 | |
497 | # set priority to HIGH |
557 | # set priority to HIGH |
498 | current->prio(PRIO_HIGH); |
558 | current->prio (PRIO_HIGH); |
499 | |
559 | |
500 | The idle coroutine ($Coro::idle) always has a lower priority than any |
560 | The idle coro ($Coro::idle) always has a lower priority than any |
501 | existing coroutine. |
561 | existing coro. |
502 | |
562 | |
503 | Changing the priority of the current coroutine will take effect immediately, |
563 | Changing the priority of the current coro will take effect immediately, |
504 | but changing the priority of coroutines in the ready queue (but not |
564 | but changing the priority of coro in the ready queue (but not |
505 | running) will only take effect after the next schedule (of that |
565 | running) will only take effect after the next schedule (of that |
506 | coroutine). This is a bug that will be fixed in some future version. |
566 | coro). This is a bug that will be fixed in some future version. |
507 | |
567 | |
508 | =item $newprio = $coroutine->nice ($change) |
568 | =item $newprio = $coro->nice ($change) |
509 | |
569 | |
510 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
570 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
511 | higher values mean lower priority, just as in unix). |
571 | higher values mean lower priority, just as in unix). |
512 | |
572 | |
513 | =item $olddesc = $coroutine->desc ($newdesc) |
573 | =item $olddesc = $coro->desc ($newdesc) |
514 | |
574 | |
515 | Sets (or gets in case the argument is missing) the description for this |
575 | Sets (or gets in case the argument is missing) the description for this |
516 | coroutine. This is just a free-form string you can associate with a coroutine. |
576 | coro. This is just a free-form string you can associate with a |
|
|
577 | coro. |
517 | |
578 | |
518 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
579 | This method simply sets the C<< $coro->{desc} >> member to the given |
519 | can modify this member directly if you wish. |
580 | string. You can modify this member directly if you wish. |
520 | |
|
|
521 | =item $coroutine->throw ([$scalar]) |
|
|
522 | |
|
|
523 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
524 | inside the coroutine at the next convinient point in time (usually after |
|
|
525 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
526 | exception object. |
|
|
527 | |
|
|
528 | The exception object will be thrown "as is" with the specified scalar in |
|
|
529 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
530 | (unlike with C<die>). |
|
|
531 | |
|
|
532 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
533 | end itself, although there is no guarentee that the exception will lead to |
|
|
534 | termination, and if the exception isn't caught it might well end the whole |
|
|
535 | program. |
|
|
536 | |
581 | |
537 | =cut |
582 | =cut |
538 | |
583 | |
539 | sub desc { |
584 | sub desc { |
540 | my $old = $_[0]{desc}; |
585 | my $old = $_[0]{desc}; |
541 | $_[0]{desc} = $_[1] if @_ > 1; |
586 | $_[0]{desc} = $_[1] if @_ > 1; |
542 | $old; |
587 | $old; |
543 | } |
588 | } |
544 | |
589 | |
|
|
590 | sub transfer { |
|
|
591 | require Carp; |
|
|
592 | Carp::croak ("You must not call ->transfer on Coro objects. Use Coro::State objects or the ->schedule_to method. Caught"); |
|
|
593 | } |
|
|
594 | |
545 | =back |
595 | =back |
546 | |
596 | |
547 | =head2 GLOBAL FUNCTIONS |
597 | =head1 GLOBAL FUNCTIONS |
548 | |
598 | |
549 | =over 4 |
599 | =over 4 |
550 | |
600 | |
551 | =item Coro::nready |
601 | =item Coro::nready |
552 | |
602 | |
553 | Returns the number of coroutines that are currently in the ready state, |
603 | Returns the number of coro that are currently in the ready state, |
554 | i.e. that can be switched to by calling C<schedule> directory or |
604 | i.e. that can be switched to by calling C<schedule> directory or |
555 | indirectly. The value C<0> means that the only runnable coroutine is the |
605 | indirectly. The value C<0> means that the only runnable coro is the |
556 | currently running one, so C<cede> would have no effect, and C<schedule> |
606 | currently running one, so C<cede> would have no effect, and C<schedule> |
557 | would cause a deadlock unless there is an idle handler that wakes up some |
607 | would cause a deadlock unless there is an idle handler that wakes up some |
558 | coroutines. |
608 | coro. |
559 | |
609 | |
560 | =item my $guard = Coro::guard { ... } |
610 | =item my $guard = Coro::guard { ... } |
561 | |
611 | |
562 | This creates and returns a guard object. Nothing happens until the object |
612 | This function still exists, but is deprecated. Please use the |
563 | gets destroyed, in which case the codeblock given as argument will be |
613 | C<Guard::guard> function instead. |
564 | executed. This is useful to free locks or other resources in case of a |
|
|
565 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
566 | guard block will be executed. The guard object supports only one method, |
|
|
567 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
|
568 | |
614 | |
569 | Example: set some flag and clear it again when the coroutine gets canceled |
|
|
570 | or the function returns: |
|
|
571 | |
|
|
572 | sub do_something { |
|
|
573 | my $guard = Coro::guard { $busy = 0 }; |
|
|
574 | $busy = 1; |
|
|
575 | |
|
|
576 | # do something that requires $busy to be true |
|
|
577 | } |
|
|
578 | |
|
|
579 | =cut |
615 | =cut |
580 | |
616 | |
581 | sub guard(&) { |
617 | BEGIN { *guard = \&Guard::guard } |
582 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
583 | } |
|
|
584 | |
|
|
585 | sub Coro::guard::cancel { |
|
|
586 | ${$_[0]} = sub { }; |
|
|
587 | } |
|
|
588 | |
|
|
589 | sub Coro::guard::DESTROY { |
|
|
590 | ${$_[0]}->(); |
|
|
591 | } |
|
|
592 | |
|
|
593 | |
618 | |
594 | =item unblock_sub { ... } |
619 | =item unblock_sub { ... } |
595 | |
620 | |
596 | This utility function takes a BLOCK or code reference and "unblocks" it, |
621 | This utility function takes a BLOCK or code reference and "unblocks" it, |
597 | returning a new coderef. Unblocking means that calling the new coderef |
622 | returning a new coderef. Unblocking means that calling the new coderef |
598 | will return immediately without blocking, returning nothing, while the |
623 | will return immediately without blocking, returning nothing, while the |
599 | original code ref will be called (with parameters) from within another |
624 | original code ref will be called (with parameters) from within another |
600 | coroutine. |
625 | coro. |
601 | |
626 | |
602 | The reason this function exists is that many event libraries (such as the |
627 | The reason this function exists is that many event libraries (such as the |
603 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
628 | venerable L<Event|Event> module) are not thread-safe (a weaker form |
604 | of thread-safety). This means you must not block within event callbacks, |
629 | of reentrancy). This means you must not block within event callbacks, |
605 | otherwise you might suffer from crashes or worse. The only event library |
630 | otherwise you might suffer from crashes or worse. The only event library |
606 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
631 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
607 | |
632 | |
608 | This function allows your callbacks to block by executing them in another |
633 | This function allows your callbacks to block by executing them in another |
609 | coroutine where it is safe to block. One example where blocking is handy |
634 | coro where it is safe to block. One example where blocking is handy |
610 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
635 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
611 | disk, for example. |
636 | disk, for example. |
612 | |
637 | |
613 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
638 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
614 | creating event callbacks that want to block. |
639 | creating event callbacks that want to block. |
615 | |
640 | |
616 | If your handler does not plan to block (e.g. simply sends a message to |
641 | If your handler does not plan to block (e.g. simply sends a message to |
617 | another coroutine, or puts some other coroutine into the ready queue), |
642 | another coro, or puts some other coro into the ready queue), there is |
618 | there is no reason to use C<unblock_sub>. |
643 | no reason to use C<unblock_sub>. |
619 | |
644 | |
620 | Note that you also need to use C<unblock_sub> for any other callbacks that |
645 | Note that you also need to use C<unblock_sub> for any other callbacks that |
621 | are indirectly executed by any C-based event loop. For example, when you |
646 | are indirectly executed by any C-based event loop. For example, when you |
622 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
647 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
623 | provides callbacks that are the result of some event callback, then you |
648 | provides callbacks that are the result of some event callback, then you |
… | |
… | |
632 | # return immediately and can be reused) and because we cannot cede |
657 | # return immediately and can be reused) and because we cannot cede |
633 | # inside an event callback. |
658 | # inside an event callback. |
634 | our $unblock_scheduler = new Coro sub { |
659 | our $unblock_scheduler = new Coro sub { |
635 | while () { |
660 | while () { |
636 | while (my $cb = pop @unblock_queue) { |
661 | while (my $cb = pop @unblock_queue) { |
637 | # this is an inlined copy of async_pool |
662 | &async_pool (@$cb); |
638 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
639 | |
663 | |
640 | $coro->{_invoke} = $cb; |
|
|
641 | $coro->ready; |
|
|
642 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
664 | # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
665 | # as the chance is very high that the async_poll coro will be back |
|
|
666 | # in the idle state when cede returns |
|
|
667 | cede; |
643 | } |
668 | } |
644 | schedule; # sleep well |
669 | schedule; # sleep well |
645 | } |
670 | } |
646 | }; |
671 | }; |
647 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
672 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
648 | |
673 | |
649 | sub unblock_sub(&) { |
674 | sub unblock_sub(&) { |
650 | my $cb = shift; |
675 | my $cb = shift; |
651 | |
676 | |
652 | sub { |
677 | sub { |
653 | unshift @unblock_queue, [$cb, @_]; |
678 | unshift @unblock_queue, [$cb, @_]; |
654 | $unblock_scheduler->ready; |
679 | $unblock_scheduler->ready; |
655 | } |
680 | } |
656 | } |
681 | } |
657 | |
682 | |
|
|
683 | =item $cb = Coro::rouse_cb |
|
|
684 | |
|
|
685 | Create and return a "rouse callback". That's a code reference that, |
|
|
686 | when called, will remember a copy of its arguments and notify the owner |
|
|
687 | coro of the callback. |
|
|
688 | |
|
|
689 | See the next function. |
|
|
690 | |
|
|
691 | =item @args = Coro::rouse_wait [$cb] |
|
|
692 | |
|
|
693 | Wait for the specified rouse callback (or the last one that was created in |
|
|
694 | this coro). |
|
|
695 | |
|
|
696 | As soon as the callback is invoked (or when the callback was invoked |
|
|
697 | before C<rouse_wait>), it will return the arguments originally passed to |
|
|
698 | the rouse callback. |
|
|
699 | |
|
|
700 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
|
|
701 | |
658 | =back |
702 | =back |
659 | |
703 | |
660 | =cut |
704 | =cut |
661 | |
705 | |
662 | 1; |
706 | 1; |
663 | |
707 | |
|
|
708 | =head1 HOW TO WAIT FOR A CALLBACK |
|
|
709 | |
|
|
710 | It is very common for a coro to wait for some callback to be |
|
|
711 | called. This occurs naturally when you use coro in an otherwise |
|
|
712 | event-based program, or when you use event-based libraries. |
|
|
713 | |
|
|
714 | These typically register a callback for some event, and call that callback |
|
|
715 | when the event occured. In a coro, however, you typically want to |
|
|
716 | just wait for the event, simplyifying things. |
|
|
717 | |
|
|
718 | For example C<< AnyEvent->child >> registers a callback to be called when |
|
|
719 | a specific child has exited: |
|
|
720 | |
|
|
721 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
|
|
722 | |
|
|
723 | But from within a coro, you often just want to write this: |
|
|
724 | |
|
|
725 | my $status = wait_for_child $pid; |
|
|
726 | |
|
|
727 | Coro offers two functions specifically designed to make this easy, |
|
|
728 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
|
|
729 | |
|
|
730 | The first function, C<rouse_cb>, generates and returns a callback that, |
|
|
731 | when invoked, will save its arguments and notify the coro that |
|
|
732 | created the callback. |
|
|
733 | |
|
|
734 | The second function, C<rouse_wait>, waits for the callback to be called |
|
|
735 | (by calling C<schedule> to go to sleep) and returns the arguments |
|
|
736 | originally passed to the callback. |
|
|
737 | |
|
|
738 | Using these functions, it becomes easy to write the C<wait_for_child> |
|
|
739 | function mentioned above: |
|
|
740 | |
|
|
741 | sub wait_for_child($) { |
|
|
742 | my ($pid) = @_; |
|
|
743 | |
|
|
744 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
|
|
745 | |
|
|
746 | my ($rpid, $rstatus) = Coro::rouse_wait; |
|
|
747 | $rstatus |
|
|
748 | } |
|
|
749 | |
|
|
750 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
|
|
751 | you can roll your own, using C<schedule>: |
|
|
752 | |
|
|
753 | sub wait_for_child($) { |
|
|
754 | my ($pid) = @_; |
|
|
755 | |
|
|
756 | # store the current coro in $current, |
|
|
757 | # and provide result variables for the closure passed to ->child |
|
|
758 | my $current = $Coro::current; |
|
|
759 | my ($done, $rstatus); |
|
|
760 | |
|
|
761 | # pass a closure to ->child |
|
|
762 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
|
|
763 | $rstatus = $_[1]; # remember rstatus |
|
|
764 | $done = 1; # mark $rstatus as valud |
|
|
765 | }); |
|
|
766 | |
|
|
767 | # wait until the closure has been called |
|
|
768 | schedule while !$done; |
|
|
769 | |
|
|
770 | $rstatus |
|
|
771 | } |
|
|
772 | |
|
|
773 | |
664 | =head1 BUGS/LIMITATIONS |
774 | =head1 BUGS/LIMITATIONS |
665 | |
775 | |
|
|
776 | =over 4 |
|
|
777 | |
|
|
778 | =item fork with pthread backend |
|
|
779 | |
|
|
780 | When Coro is compiled using the pthread backend (which isn't recommended |
|
|
781 | but required on many BSDs as their libcs are completely broken), then |
|
|
782 | coro will not survive a fork. There is no known workaround except to |
|
|
783 | fix your libc and use a saner backend. |
|
|
784 | |
|
|
785 | =item perl process emulation ("threads") |
|
|
786 | |
666 | This module is not perl-pseudo-thread-safe. You should only ever use this |
787 | This module is not perl-pseudo-thread-safe. You should only ever use this |
667 | module from the same thread (this requirement might be removed in the |
788 | module from the first thread (this requirement might be removed in the |
668 | future to allow per-thread schedulers, but Coro::State does not yet allow |
789 | future to allow per-thread schedulers, but Coro::State does not yet allow |
669 | this). I recommend disabling thread support and using processes, as this |
790 | this). I recommend disabling thread support and using processes, as having |
670 | is much faster and uses less memory. |
791 | the windows process emulation enabled under unix roughly halves perl |
|
|
792 | performance, even when not used. |
|
|
793 | |
|
|
794 | =item coro switching is not signal safe |
|
|
795 | |
|
|
796 | You must not switch to another coro from within a signal handler |
|
|
797 | (only relevant with %SIG - most event libraries provide safe signals). |
|
|
798 | |
|
|
799 | That means you I<MUST NOT> call any function that might "block" the |
|
|
800 | current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
|
|
801 | anything that calls those. Everything else, including calling C<ready>, |
|
|
802 | works. |
|
|
803 | |
|
|
804 | =back |
|
|
805 | |
671 | |
806 | |
672 | =head1 SEE ALSO |
807 | =head1 SEE ALSO |
673 | |
808 | |
674 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
809 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
675 | |
810 | |
676 | Debugging: L<Coro::Debug>. |
811 | Debugging: L<Coro::Debug>. |
677 | |
812 | |
678 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
813 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
679 | |
814 | |
680 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
815 | Locking and IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
|
|
816 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
681 | |
817 | |
682 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
818 | I/O and Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
683 | |
819 | |
684 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
820 | Compatibility with other modules: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
|
|
821 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
|
|
822 | L<Coro::Select>. |
685 | |
823 | |
686 | XS API: L<Coro::MakeMaker>. |
824 | XS API: L<Coro::MakeMaker>. |
687 | |
825 | |
688 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
826 | Low level Configuration, Thread Environment, Continuations: L<Coro::State>. |
689 | |
827 | |
690 | =head1 AUTHOR |
828 | =head1 AUTHOR |
691 | |
829 | |
692 | Marc Lehmann <schmorp@schmorp.de> |
830 | Marc Lehmann <schmorp@schmorp.de> |
693 | http://home.schmorp.de/ |
831 | http://home.schmorp.de/ |