… | |
… | |
8 | |
8 | |
9 | async { |
9 | async { |
10 | # some asynchronous thread of execution |
10 | # some asynchronous thread of execution |
11 | }; |
11 | }; |
12 | |
12 | |
13 | # alternatively create an async process like this: |
13 | # alternatively create an async coroutine like this: |
14 | |
14 | |
15 | sub some_func : Coro { |
15 | sub some_func : Coro { |
16 | # some more async code |
16 | # some more async code |
17 | } |
17 | } |
18 | |
18 | |
19 | yield; |
19 | cede; |
20 | |
20 | |
21 | =head1 DESCRIPTION |
21 | =head1 DESCRIPTION |
22 | |
22 | |
23 | This module collection manages coroutines. Coroutines are similar to |
23 | This module collection manages coroutines. Coroutines are similar |
24 | Threads but don't run in parallel. |
24 | to threads but don't run in parallel at the same time even on SMP |
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25 | machines. The specific flavor of coroutine used in this module also |
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26 | guarantees you that it will not switch between coroutines unless |
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27 | necessary, at easily-identified points in your program, so locking and |
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28 | parallel access are rarely an issue, making coroutine programming much |
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29 | safer than threads programming. |
25 | |
30 | |
26 | This module is still experimental, see the BUGS section below. |
31 | (Perl, however, does not natively support real threads but instead does a |
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32 | very slow and memory-intensive emulation of processes using threads. This |
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33 | is a performance win on Windows machines, and a loss everywhere else). |
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34 | |
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35 | In this module, coroutines are defined as "callchain + lexical variables + |
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36 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
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37 | its own set of lexicals and its own set of perls most important global |
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38 | variables. |
27 | |
39 | |
28 | =cut |
40 | =cut |
29 | |
41 | |
30 | package Coro; |
42 | package Coro; |
31 | |
43 | |
|
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44 | use strict; |
|
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45 | no warnings "uninitialized"; |
|
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46 | |
32 | use Coro::State; |
47 | use Coro::State; |
33 | |
48 | |
34 | use base Exporter; |
49 | use base qw(Coro::State Exporter); |
35 | |
50 | |
36 | $VERSION = 0.09; |
51 | our $idle; # idle handler |
|
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52 | our $main; # main coroutine |
|
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53 | our $current; # current coroutine |
37 | |
54 | |
|
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55 | our $VERSION = '3.8'; |
|
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56 | |
38 | @EXPORT = qw(async yield schedule terminate current); |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
39 | @EXPORT_OK = qw($current); |
58 | our %EXPORT_TAGS = ( |
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59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
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60 | ); |
|
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61 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
40 | |
62 | |
41 | { |
63 | { |
42 | use subs 'async'; |
|
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43 | |
|
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44 | my @async; |
64 | my @async; |
|
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65 | my $init; |
45 | |
66 | |
46 | # this way of handling attributes simply is NOT scalable ;() |
67 | # this way of handling attributes simply is NOT scalable ;() |
47 | sub import { |
68 | sub import { |
|
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69 | no strict 'refs'; |
|
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70 | |
48 | Coro->export_to_level(1, @_); |
71 | Coro->export_to_level (1, @_); |
|
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72 | |
49 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
73 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
50 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
74 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
51 | my ($package, $ref) = (shift, shift); |
75 | my ($package, $ref) = (shift, shift); |
52 | my @attrs; |
76 | my @attrs; |
53 | for (@_) { |
77 | for (@_) { |
54 | if ($_ eq "Coro") { |
78 | if ($_ eq "Coro") { |
55 | push @async, $ref; |
79 | push @async, $ref; |
|
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80 | unless ($init++) { |
|
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81 | eval q{ |
|
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82 | sub INIT { |
|
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83 | &async(pop @async) while @async; |
|
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84 | } |
|
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85 | }; |
|
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86 | } |
56 | } else { |
87 | } else { |
57 | push @attrs, $_; |
88 | push @attrs, $_; |
58 | } |
89 | } |
59 | } |
90 | } |
60 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
91 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
61 | }; |
92 | }; |
62 | } |
93 | } |
63 | |
94 | |
64 | sub INIT { |
|
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65 | async pop @async while @async; |
|
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66 | } |
|
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67 | } |
95 | } |
|
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96 | |
|
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97 | =over 4 |
68 | |
98 | |
69 | =item $main |
99 | =item $main |
70 | |
100 | |
71 | This coroutine represents the main program. |
101 | This coroutine represents the main program. |
72 | |
102 | |
73 | =cut |
103 | =cut |
74 | |
104 | |
75 | our $main = new Coro; |
105 | $main = new Coro; |
76 | |
106 | |
77 | =item $current (or as function: current) |
107 | =item $current (or as function: current) |
78 | |
108 | |
79 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
109 | The current coroutine (the last coroutine switched to). The initial value |
|
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110 | is C<$main> (of course). |
80 | |
111 | |
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112 | This variable is B<strictly> I<read-only>. It is provided for performance |
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113 | reasons. If performance is not essential you are encouraged to use the |
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114 | C<Coro::current> function instead. |
|
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115 | |
81 | =cut |
116 | =cut |
|
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117 | |
|
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118 | $main->{desc} = "[main::]"; |
82 | |
119 | |
83 | # maybe some other module used Coro::Specific before... |
120 | # maybe some other module used Coro::Specific before... |
84 | if ($current) { |
|
|
85 | $main->{specific} = $current->{specific}; |
121 | $main->{_specific} = $current->{_specific} |
86 | } |
122 | if $current; |
87 | |
123 | |
88 | our $current = $main; |
124 | _set_current $main; |
89 | |
125 | |
90 | sub current() { $current } |
126 | sub current() { $current } |
91 | |
127 | |
92 | =item $idle |
128 | =item $idle |
93 | |
129 | |
94 | The coroutine to switch to when no other coroutine is running. The default |
130 | A callback that is called whenever the scheduler finds no ready coroutines |
95 | implementation prints "FATAL: deadlock detected" and exits. |
131 | to run. The default implementation prints "FATAL: deadlock detected" and |
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132 | exits, because the program has no other way to continue. |
96 | |
133 | |
97 | =cut |
134 | This hook is overwritten by modules such as C<Coro::Timer> and |
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135 | C<Coro::Event> to wait on an external event that hopefully wake up a |
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136 | coroutine so the scheduler can run it. |
98 | |
137 | |
99 | # should be done using priorities :( |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
100 | our $idle = new Coro sub { |
139 | handlers), then it must be prepared to be called recursively. |
101 | print STDERR "FATAL: deadlock detected\n"; |
140 | |
102 | exit(51); |
141 | =cut |
|
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142 | |
|
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143 | $idle = sub { |
|
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144 | require Carp; |
|
|
145 | Carp::croak ("FATAL: deadlock detected"); |
103 | }; |
146 | }; |
104 | |
147 | |
105 | # we really need priorities... |
148 | sub _cancel { |
106 | my @ready; # the ready queue. hehe, rather broken ;) |
149 | my ($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 | |
|
|
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 |
|
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161 | # cannot destroy itself. |
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162 | my @destroy; |
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163 | my $manager; |
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164 | |
|
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165 | $manager = new Coro sub { |
|
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166 | while () { |
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167 | (shift @destroy)->_cancel |
|
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168 | while @destroy; |
|
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169 | |
|
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170 | &schedule; |
|
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171 | } |
|
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172 | }; |
|
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173 | $manager->desc ("[coro manager]"); |
|
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174 | $manager->prio (PRIO_MAX); |
107 | |
175 | |
108 | # static methods. not really. |
176 | # static methods. not really. |
109 | |
177 | |
|
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178 | =back |
|
|
179 | |
110 | =head2 STATIC METHODS |
180 | =head2 STATIC METHODS |
111 | |
181 | |
112 | Static methods are actually functions that operate on the current process only. |
182 | Static methods are actually functions that operate on the current coroutine only. |
113 | |
183 | |
114 | =over 4 |
184 | =over 4 |
115 | |
185 | |
116 | =item async { ... } [@args...] |
186 | =item async { ... } [@args...] |
117 | |
187 | |
118 | Create a new asynchronous process and return it's process object |
188 | Create a new asynchronous coroutine and return it's coroutine object |
119 | (usually unused). When the sub returns the new process is automatically |
189 | (usually unused). When the sub returns the new coroutine is automatically |
120 | terminated. |
190 | terminated. |
|
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191 | |
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192 | Calling C<exit> in a coroutine will do the same as calling exit outside |
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193 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
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194 | just as it would in the main program. |
121 | |
195 | |
122 | # create a new coroutine that just prints its arguments |
196 | # create a new coroutine that just prints its arguments |
123 | async { |
197 | async { |
124 | print "@_\n"; |
198 | print "@_\n"; |
125 | } 1,2,3,4; |
199 | } 1,2,3,4; |
126 | |
200 | |
127 | The coderef you submit MUST NOT be a closure that refers to variables |
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128 | in an outer scope. This does NOT work. Pass arguments into it instead. |
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129 | |
|
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130 | =cut |
201 | =cut |
131 | |
202 | |
132 | sub async(&@) { |
203 | sub async(&@) { |
133 | my $pid = new Coro @_; |
204 | my $coro = new Coro @_; |
134 | $pid->ready; |
205 | $coro->ready; |
135 | $pid; |
206 | $coro |
|
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207 | } |
|
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208 | |
|
|
209 | =item async_pool { ... } [@args...] |
|
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210 | |
|
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211 | Similar to C<async>, but uses a coroutine pool, so you should not call |
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212 | terminate or join (although you are allowed to), and you get a coroutine |
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213 | that might have executed other code already (which can be good or bad :). |
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214 | |
|
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215 | Also, the block is executed in an C<eval> context and a warning will be |
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216 | issued in case of an exception instead of terminating the program, as |
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217 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
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218 | will not work in the expected way, unless you call terminate or cancel, |
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219 | which somehow defeats the purpose of pooling. |
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220 | |
|
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221 | The priority will be reset to C<0> after each job, otherwise the coroutine |
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222 | will be re-used "as-is". |
|
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223 | |
|
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224 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
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225 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
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226 | required. |
|
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227 | |
|
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228 | If you are concerned about pooled coroutines growing a lot because a |
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229 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
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230 | { terminate }> once per second or so to slowly replenish the pool. In |
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231 | addition to that, when the stacks used by a handler grows larger than 16kb |
|
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232 | (adjustable with $Coro::POOL_RSS) it will also exit. |
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233 | |
|
|
234 | =cut |
|
|
235 | |
|
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236 | our $POOL_SIZE = 8; |
|
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237 | our $POOL_RSS = 16 * 1024; |
|
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238 | our @async_pool; |
|
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239 | |
|
|
240 | sub pool_handler { |
|
|
241 | my $cb; |
|
|
242 | |
|
|
243 | while () { |
|
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244 | eval { |
|
|
245 | while () { |
|
|
246 | _pool_1 $cb; |
|
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247 | &$cb; |
|
|
248 | _pool_2 $cb; |
|
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249 | &schedule; |
|
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250 | } |
|
|
251 | }; |
|
|
252 | |
|
|
253 | last if $@ eq "\3terminate\2\n"; |
|
|
254 | warn $@ if $@; |
|
|
255 | } |
|
|
256 | } |
|
|
257 | |
|
|
258 | sub async_pool(&@) { |
|
|
259 | # this is also inlined into the unlock_scheduler |
|
|
260 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
261 | |
|
|
262 | $coro->{_invoke} = [@_]; |
|
|
263 | $coro->ready; |
|
|
264 | |
|
|
265 | $coro |
136 | } |
266 | } |
137 | |
267 | |
138 | =item schedule |
268 | =item schedule |
139 | |
269 | |
140 | Calls the scheduler. Please note that the current process will not be put |
270 | Calls the scheduler. Please note that the current coroutine will not be put |
141 | into the ready queue, so calling this function usually means you will |
271 | into the ready queue, so calling this function usually means you will |
142 | never be called again. |
272 | never be called again unless something else (e.g. an event handler) calls |
|
|
273 | ready. |
143 | |
274 | |
144 | =cut |
275 | The canonical way to wait on external events is this: |
145 | |
276 | |
146 | my $prev; |
277 | { |
|
|
278 | # remember current coroutine |
|
|
279 | my $current = $Coro::current; |
147 | |
280 | |
148 | sub schedule { |
281 | # register a hypothetical event handler |
149 | # should be done using priorities :( |
282 | on_event_invoke sub { |
150 | ($prev, $current) = ($current, shift @ready || $idle); |
283 | # wake up sleeping coroutine |
151 | Coro::State::transfer($prev, $current); |
|
|
152 | } |
|
|
153 | |
|
|
154 | =item yield |
|
|
155 | |
|
|
156 | Yield to other processes. This function puts the current process into the |
|
|
157 | ready queue and calls C<schedule>. |
|
|
158 | |
|
|
159 | =cut |
|
|
160 | |
|
|
161 | sub yield { |
|
|
162 | $current->ready; |
284 | $current->ready; |
163 | &schedule; |
285 | undef $current; |
164 | } |
286 | }; |
165 | |
287 | |
|
|
288 | # call schedule until event occurred. |
|
|
289 | # in case we are woken up for other reasons |
|
|
290 | # (current still defined), loop. |
|
|
291 | Coro::schedule while $current; |
|
|
292 | } |
|
|
293 | |
|
|
294 | =item cede |
|
|
295 | |
|
|
296 | "Cede" to other coroutines. This function puts the current coroutine into the |
|
|
297 | ready queue and calls C<schedule>, which has the effect of giving up the |
|
|
298 | current "timeslice" to other coroutines of the same or higher priority. |
|
|
299 | |
|
|
300 | Returns true if at least one coroutine switch has happened. |
|
|
301 | |
|
|
302 | =item Coro::cede_notself |
|
|
303 | |
|
|
304 | Works like cede, but is not exported by default and will cede to any |
|
|
305 | coroutine, regardless of priority, once. |
|
|
306 | |
|
|
307 | Returns true if at least one coroutine switch has happened. |
|
|
308 | |
166 | =item terminate |
309 | =item terminate [arg...] |
167 | |
310 | |
168 | Terminates the current process. |
311 | Terminates the current coroutine with the given status values (see L<cancel>). |
169 | |
312 | |
170 | Future versions of this function will allow result arguments. |
313 | =item killall |
|
|
314 | |
|
|
315 | Kills/terminates/cancels all coroutines except the currently running |
|
|
316 | one. This is useful after a fork, either in the child or the parent, as |
|
|
317 | usually only one of them should inherit the running coroutines. |
171 | |
318 | |
172 | =cut |
319 | =cut |
173 | |
320 | |
174 | sub terminate { |
321 | sub terminate { |
175 | $current->{_results} = [@_]; |
322 | $current->cancel (@_); |
176 | &schedule; |
323 | } |
|
|
324 | |
|
|
325 | sub killall { |
|
|
326 | for (Coro::State::list) { |
|
|
327 | $_->cancel |
|
|
328 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
|
|
329 | } |
177 | } |
330 | } |
178 | |
331 | |
179 | =back |
332 | =back |
180 | |
333 | |
181 | # dynamic methods |
334 | # dynamic methods |
182 | |
335 | |
183 | =head2 PROCESS METHODS |
336 | =head2 COROUTINE METHODS |
184 | |
337 | |
185 | These are the methods you can call on process objects. |
338 | These are the methods you can call on coroutine objects. |
186 | |
339 | |
187 | =over 4 |
340 | =over 4 |
188 | |
341 | |
189 | =item new Coro \&sub [, @args...] |
342 | =item new Coro \&sub [, @args...] |
190 | |
343 | |
191 | Create a new process and return it. When the sub returns the process |
344 | Create a new coroutine and return it. When the sub returns the coroutine |
192 | automatically terminates. To start the process you must first put it into |
345 | automatically terminates as if C<terminate> with the returned values were |
|
|
346 | called. To make the coroutine run you must first put it into the ready queue |
193 | the ready queue by calling the ready method. |
347 | by calling the ready method. |
194 | |
348 | |
195 | The coderef you submit MUST NOT be a closure that refers to variables |
349 | See C<async> for additional discussion. |
196 | in an outer scope. This does NOT work. Pass arguments into it instead. |
|
|
197 | |
350 | |
198 | =cut |
351 | =cut |
199 | |
352 | |
200 | sub _newcoro { |
353 | sub _run_coro { |
201 | terminate &{+shift}; |
354 | terminate &{+shift}; |
202 | } |
355 | } |
203 | |
356 | |
204 | sub new { |
357 | sub new { |
205 | my $class = shift; |
358 | my $class = shift; |
206 | bless { |
|
|
207 | _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), |
|
|
208 | }, $class; |
|
|
209 | } |
|
|
210 | |
359 | |
211 | =item $process->ready |
360 | $class->SUPER::new (\&_run_coro, @_) |
|
|
361 | } |
212 | |
362 | |
213 | Put the current process into the ready queue. |
363 | =item $success = $coroutine->ready |
214 | |
364 | |
215 | =cut |
365 | Put the given coroutine into the ready queue (according to it's priority) |
|
|
366 | and return true. If the coroutine is already in the ready queue, do nothing |
|
|
367 | and return false. |
216 | |
368 | |
217 | sub ready { |
369 | =item $is_ready = $coroutine->is_ready |
218 | push @ready, $_[0]; |
370 | |
|
|
371 | Return wether the coroutine is currently the ready queue or not, |
|
|
372 | |
|
|
373 | =item $coroutine->cancel (arg...) |
|
|
374 | |
|
|
375 | Terminates the given coroutine and makes it return the given arguments as |
|
|
376 | status (default: the empty list). Never returns if the coroutine is the |
|
|
377 | current coroutine. |
|
|
378 | |
|
|
379 | =cut |
|
|
380 | |
|
|
381 | sub cancel { |
|
|
382 | my $self = shift; |
|
|
383 | $self->{_status} = [@_]; |
|
|
384 | |
|
|
385 | if ($current == $self) { |
|
|
386 | push @destroy, $self; |
|
|
387 | $manager->ready; |
|
|
388 | &schedule while 1; |
|
|
389 | } else { |
|
|
390 | $self->_cancel; |
|
|
391 | } |
|
|
392 | } |
|
|
393 | |
|
|
394 | =item $coroutine->join |
|
|
395 | |
|
|
396 | Wait until the coroutine terminates and return any values given to the |
|
|
397 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
|
|
398 | from multiple coroutines. |
|
|
399 | |
|
|
400 | =cut |
|
|
401 | |
|
|
402 | sub join { |
|
|
403 | my $self = shift; |
|
|
404 | |
|
|
405 | unless ($self->{_status}) { |
|
|
406 | my $current = $current; |
|
|
407 | |
|
|
408 | push @{$self->{_on_destroy}}, sub { |
|
|
409 | $current->ready; |
|
|
410 | undef $current; |
|
|
411 | }; |
|
|
412 | |
|
|
413 | &schedule while $current; |
|
|
414 | } |
|
|
415 | |
|
|
416 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
|
|
417 | } |
|
|
418 | |
|
|
419 | =item $coroutine->on_destroy (\&cb) |
|
|
420 | |
|
|
421 | Registers a callback that is called when this coroutine gets destroyed, |
|
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422 | but before it is joined. The callback gets passed the terminate arguments, |
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423 | if any. |
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424 | |
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425 | =cut |
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426 | |
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427 | sub on_destroy { |
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428 | my ($self, $cb) = @_; |
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429 | |
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430 | push @{ $self->{_on_destroy} }, $cb; |
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431 | } |
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432 | |
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433 | =item $oldprio = $coroutine->prio ($newprio) |
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434 | |
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435 | Sets (or gets, if the argument is missing) the priority of the |
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436 | coroutine. Higher priority coroutines get run before lower priority |
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437 | coroutines. Priorities are small signed integers (currently -4 .. +3), |
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438 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
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439 | to get then): |
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440 | |
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441 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
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442 | 3 > 1 > 0 > -1 > -3 > -4 |
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443 | |
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444 | # set priority to HIGH |
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445 | current->prio(PRIO_HIGH); |
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446 | |
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447 | The idle coroutine ($Coro::idle) always has a lower priority than any |
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448 | existing coroutine. |
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449 | |
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450 | Changing the priority of the current coroutine will take effect immediately, |
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451 | but changing the priority of coroutines in the ready queue (but not |
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452 | running) will only take effect after the next schedule (of that |
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453 | coroutine). This is a bug that will be fixed in some future version. |
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454 | |
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455 | =item $newprio = $coroutine->nice ($change) |
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456 | |
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457 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
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458 | higher values mean lower priority, just as in unix). |
|
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459 | |
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460 | =item $olddesc = $coroutine->desc ($newdesc) |
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461 | |
|
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462 | Sets (or gets in case the argument is missing) the description for this |
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463 | coroutine. This is just a free-form string you can associate with a coroutine. |
|
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464 | |
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465 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
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466 | can modify this member directly if you wish. |
|
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467 | |
|
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468 | =cut |
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469 | |
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470 | sub desc { |
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471 | my $old = $_[0]{desc}; |
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472 | $_[0]{desc} = $_[1] if @_ > 1; |
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473 | $old; |
219 | } |
474 | } |
220 | |
475 | |
221 | =back |
476 | =back |
222 | |
477 | |
|
|
478 | =head2 GLOBAL FUNCTIONS |
|
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479 | |
|
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480 | =over 4 |
|
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481 | |
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|
482 | =item Coro::nready |
|
|
483 | |
|
|
484 | Returns the number of coroutines that are currently in the ready state, |
|
|
485 | i.e. that can be switched to. The value C<0> means that the only runnable |
|
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486 | coroutine is the currently running one, so C<cede> would have no effect, |
|
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487 | and C<schedule> would cause a deadlock unless there is an idle handler |
|
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488 | that wakes up some coroutines. |
|
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489 | |
|
|
490 | =item my $guard = Coro::guard { ... } |
|
|
491 | |
|
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492 | This creates and returns a guard object. Nothing happens until the object |
|
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493 | gets destroyed, in which case the codeblock given as argument will be |
|
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494 | executed. This is useful to free locks or other resources in case of a |
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495 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
496 | guard block will be executed. The guard object supports only one method, |
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497 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
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498 | |
|
|
499 | Example: set some flag and clear it again when the coroutine gets canceled |
|
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500 | or the function returns: |
|
|
501 | |
|
|
502 | sub do_something { |
|
|
503 | my $guard = Coro::guard { $busy = 0 }; |
|
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504 | $busy = 1; |
|
|
505 | |
|
|
506 | # do something that requires $busy to be true |
|
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507 | } |
|
|
508 | |
|
|
509 | =cut |
|
|
510 | |
|
|
511 | sub guard(&) { |
|
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512 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
513 | } |
|
|
514 | |
|
|
515 | sub Coro::guard::cancel { |
|
|
516 | ${$_[0]} = sub { }; |
|
|
517 | } |
|
|
518 | |
|
|
519 | sub Coro::guard::DESTROY { |
|
|
520 | ${$_[0]}->(); |
|
|
521 | } |
|
|
522 | |
|
|
523 | |
|
|
524 | =item unblock_sub { ... } |
|
|
525 | |
|
|
526 | This utility function takes a BLOCK or code reference and "unblocks" it, |
|
|
527 | returning the new coderef. This means that the new coderef will return |
|
|
528 | immediately without blocking, returning nothing, while the original code |
|
|
529 | ref will be called (with parameters) from within its own coroutine. |
|
|
530 | |
|
|
531 | The reason this function exists is that many event libraries (such as the |
|
|
532 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
|
|
533 | of thread-safety). This means you must not block within event callbacks, |
|
|
534 | otherwise you might suffer from crashes or worse. |
|
|
535 | |
|
|
536 | This function allows your callbacks to block by executing them in another |
|
|
537 | coroutine where it is safe to block. One example where blocking is handy |
|
|
538 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
|
|
539 | disk. |
|
|
540 | |
|
|
541 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
|
|
542 | creating event callbacks that want to block. |
|
|
543 | |
|
|
544 | =cut |
|
|
545 | |
|
|
546 | our @unblock_queue; |
|
|
547 | |
|
|
548 | # we create a special coro because we want to cede, |
|
|
549 | # to reduce pressure on the coro pool (because most callbacks |
|
|
550 | # return immediately and can be reused) and because we cannot cede |
|
|
551 | # inside an event callback. |
|
|
552 | our $unblock_scheduler = new Coro sub { |
|
|
553 | while () { |
|
|
554 | while (my $cb = pop @unblock_queue) { |
|
|
555 | # this is an inlined copy of async_pool |
|
|
556 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
557 | |
|
|
558 | $coro->{_invoke} = $cb; |
|
|
559 | $coro->ready; |
|
|
560 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
561 | } |
|
|
562 | schedule; # sleep well |
|
|
563 | } |
|
|
564 | }; |
|
|
565 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
|
|
566 | |
|
|
567 | sub unblock_sub(&) { |
|
|
568 | my $cb = shift; |
|
|
569 | |
|
|
570 | sub { |
|
|
571 | unshift @unblock_queue, [$cb, @_]; |
|
|
572 | $unblock_scheduler->ready; |
|
|
573 | } |
|
|
574 | } |
|
|
575 | |
|
|
576 | =back |
|
|
577 | |
223 | =cut |
578 | =cut |
224 | |
579 | |
225 | 1; |
580 | 1; |
226 | |
581 | |
227 | =head1 BUGS/LIMITATIONS |
582 | =head1 BUGS/LIMITATIONS |
228 | |
583 | |
229 | - could be faster, especially when the core would introduce special |
584 | - you must make very sure that no coro is still active on global |
230 | support for coroutines (like it does for threads). |
585 | destruction. very bad things might happen otherwise (usually segfaults). |
231 | - there is still a memleak on coroutine termination that I could not |
586 | |
232 | identify. Could be as small as a single SV. |
|
|
233 | - this module is not well-tested. |
|
|
234 | - if variables or arguments "disappear" (become undef) or become |
|
|
235 | corrupted please contact the author so he cen iron out the |
|
|
236 | remaining bugs. |
|
|
237 | - this module is not thread-safe. You must only ever use this module from |
587 | - this module is not thread-safe. You should only ever use this module |
238 | the same thread (this requirement might be loosened in the future to |
588 | from the same thread (this requirement might be loosened in the future |
239 | allow per-thread schedulers, but Coro::Satte does not yet allow this). |
589 | to allow per-thread schedulers, but Coro::State does not yet allow |
|
|
590 | this). |
240 | |
591 | |
241 | =head1 SEE ALSO |
592 | =head1 SEE ALSO |
242 | |
593 | |
243 | L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
594 | Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
244 | L<Coro::Signal>, L<Coro::State>, L<Coro::Event>. |
595 | |
|
|
596 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
|
|
597 | |
|
|
598 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
|
|
599 | |
|
|
600 | Embedding: L<Coro:MakeMaker> |
245 | |
601 | |
246 | =head1 AUTHOR |
602 | =head1 AUTHOR |
247 | |
603 | |
248 | Marc Lehmann <pcg@goof.com> |
604 | Marc Lehmann <schmorp@schmorp.de> |
249 | http://www.goof.com/pcg/marc/ |
605 | http://home.schmorp.de/ |
250 | |
606 | |
251 | =cut |
607 | =cut |
252 | |
608 | |