… | |
… | |
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 | cede; |
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 | |
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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 | |
26 | In this module, coroutines are defined as "callchain + lexical variables |
35 | In this module, coroutines are defined as "callchain + lexical variables + |
27 | + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own |
36 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
28 | callchain, it's own set of lexicals and it's own set of perl's most |
37 | its own set of lexicals and its own set of perls most important global |
29 | important global variables. |
38 | variables. |
30 | |
39 | |
31 | =cut |
40 | =cut |
32 | |
41 | |
33 | package Coro; |
42 | package Coro; |
34 | |
43 | |
35 | BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") } |
44 | use strict; |
|
|
45 | no warnings "uninitialized"; |
36 | |
46 | |
37 | use Coro::State; |
47 | use Coro::State; |
38 | |
48 | |
39 | use vars qw($idle $main $current); |
49 | use base qw(Coro::State Exporter); |
40 | |
50 | |
41 | use base Exporter; |
51 | our $idle; # idle handler |
|
|
52 | our $main; # main coroutine |
|
|
53 | our $current; # current coroutine |
42 | |
54 | |
43 | $VERSION = 0.95; |
55 | our $VERSION = '4.0'; |
44 | |
56 | |
45 | @EXPORT = qw(async cede schedule terminate current); |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
46 | %EXPORT_TAGS = ( |
58 | our %EXPORT_TAGS = ( |
47 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
48 | ); |
60 | ); |
49 | @EXPORT_OK = @{$EXPORT_TAGS{prio}}; |
61 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
50 | |
62 | |
51 | { |
63 | { |
52 | my @async; |
64 | my @async; |
53 | my $init; |
65 | my $init; |
54 | |
66 | |
55 | # this way of handling attributes simply is NOT scalable ;() |
67 | # this way of handling attributes simply is NOT scalable ;() |
56 | sub import { |
68 | sub import { |
|
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69 | no strict 'refs'; |
|
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70 | |
57 | Coro->export_to_level(1, @_); |
71 | Coro->export_to_level (1, @_); |
|
|
72 | |
58 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
73 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
59 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
74 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
60 | my ($package, $ref) = (shift, shift); |
75 | my ($package, $ref) = (shift, shift); |
61 | my @attrs; |
76 | my @attrs; |
62 | for (@_) { |
77 | for (@_) { |
… | |
… | |
89 | |
104 | |
90 | $main = new Coro; |
105 | $main = new Coro; |
91 | |
106 | |
92 | =item $current (or as function: current) |
107 | =item $current (or as function: current) |
93 | |
108 | |
94 | The current coroutine (the last coroutine switched to). The initial value is C<$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). |
95 | |
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 | |
96 | =cut |
116 | =cut |
|
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117 | |
|
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118 | $main->{desc} = "[main::]"; |
97 | |
119 | |
98 | # maybe some other module used Coro::Specific before... |
120 | # maybe some other module used Coro::Specific before... |
99 | if ($current) { |
|
|
100 | $main->{specific} = $current->{specific}; |
121 | $main->{_specific} = $current->{_specific} |
101 | } |
122 | if $current; |
102 | |
123 | |
103 | $current = $main; |
124 | _set_current $main; |
104 | |
125 | |
105 | sub current() { $current } |
126 | sub current() { $current } |
106 | |
127 | |
107 | =item $idle |
128 | =item $idle |
108 | |
129 | |
109 | 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 |
110 | 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. |
111 | |
133 | |
112 | =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. |
113 | |
137 | |
114 | # should be done using priorities :( |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
115 | $idle = new Coro sub { |
139 | handlers), then it must be prepared to be called recursively. |
116 | print STDERR "FATAL: deadlock detected\n"; |
140 | |
117 | exit(51); |
141 | =cut |
|
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142 | |
|
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143 | $idle = sub { |
|
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144 | require Carp; |
|
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145 | Carp::croak ("FATAL: deadlock detected"); |
118 | }; |
146 | }; |
|
|
147 | |
|
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148 | sub _cancel { |
|
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149 | my ($self) = @_; |
|
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150 | |
|
|
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 | } |
119 | |
159 | |
120 | # this coroutine is necessary because a coroutine |
160 | # this coroutine is necessary because a coroutine |
121 | # cannot destroy itself. |
161 | # cannot destroy itself. |
122 | my @destroy; |
162 | my @destroy; |
123 | my $manager; |
163 | my $manager; |
|
|
164 | |
124 | $manager = new Coro sub { |
165 | $manager = new Coro sub { |
125 | while () { |
166 | while () { |
126 | # by overwriting the state object with the manager we destroy it |
167 | (shift @destroy)->_cancel |
127 | # while still being able to schedule this coroutine (in case it has |
|
|
128 | # been readied multiple times. this is harmless since the manager |
|
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129 | # can be called as many times as neccessary and will always |
|
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130 | # remove itself from the runqueue |
|
|
131 | while (@destroy) { |
168 | while @destroy; |
132 | my $coro = pop @destroy; |
169 | |
133 | $coro->{status} ||= []; |
|
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134 | $_->ready for @{delete $coro->{join} || []}; |
|
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135 | $coro->{_coro_state} = $manager->{_coro_state}; |
|
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136 | } |
|
|
137 | &schedule; |
170 | &schedule; |
138 | } |
171 | } |
139 | }; |
172 | }; |
|
|
173 | $manager->desc ("[coro manager]"); |
|
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174 | $manager->prio (PRIO_MAX); |
140 | |
175 | |
141 | # static methods. not really. |
176 | # static methods. not really. |
142 | |
177 | |
143 | =back |
178 | =back |
144 | |
179 | |
145 | =head2 STATIC METHODS |
180 | =head2 STATIC METHODS |
146 | |
181 | |
147 | 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. |
148 | |
183 | |
149 | =over 4 |
184 | =over 4 |
150 | |
185 | |
151 | =item async { ... } [@args...] |
186 | =item async { ... } [@args...] |
152 | |
187 | |
153 | Create a new asynchronous process and return it's process object |
188 | Create a new asynchronous coroutine and return it's coroutine object |
154 | (usually unused). When the sub returns the new process is automatically |
189 | (usually unused). When the sub returns the new coroutine is automatically |
155 | terminated. |
190 | terminated. |
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191 | |
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192 | See the C<Coro::State::new> constructor for info about the coroutine |
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193 | environment. |
|
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194 | |
|
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195 | Calling C<exit> in a coroutine will do the same as calling exit outside |
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196 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
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197 | just as it would in the main program. |
156 | |
198 | |
157 | # create a new coroutine that just prints its arguments |
199 | # create a new coroutine that just prints its arguments |
158 | async { |
200 | async { |
159 | print "@_\n"; |
201 | print "@_\n"; |
160 | } 1,2,3,4; |
202 | } 1,2,3,4; |
161 | |
203 | |
162 | =cut |
204 | =cut |
163 | |
205 | |
164 | sub async(&@) { |
206 | sub async(&@) { |
165 | my $pid = new Coro @_; |
207 | my $coro = new Coro @_; |
166 | $manager->ready; # this ensures that the stack is cloned from the manager |
|
|
167 | $pid->ready; |
208 | $coro->ready; |
168 | $pid; |
209 | $coro |
|
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210 | } |
|
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211 | |
|
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212 | =item async_pool { ... } [@args...] |
|
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213 | |
|
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214 | Similar to C<async>, but uses a coroutine pool, so you should not call |
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215 | terminate or join (although you are allowed to), and you get a coroutine |
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216 | that might have executed other code already (which can be good or bad :). |
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217 | |
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218 | Also, the block is executed in an C<eval> context and a warning will be |
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219 | issued in case of an exception instead of terminating the program, as |
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220 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
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221 | will not work in the expected way, unless you call terminate or cancel, |
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222 | which somehow defeats the purpose of pooling. |
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223 | |
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224 | The priority will be reset to C<0> after each job, otherwise the coroutine |
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225 | will be re-used "as-is". |
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226 | |
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227 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
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228 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
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229 | required. |
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230 | |
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231 | If you are concerned about pooled coroutines growing a lot because a |
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232 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
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233 | { terminate }> once per second or so to slowly replenish the pool. In |
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234 | addition to that, when the stacks used by a handler grows larger than 16kb |
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235 | (adjustable with $Coro::POOL_RSS) it will also exit. |
|
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236 | |
|
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237 | =cut |
|
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238 | |
|
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239 | our $POOL_SIZE = 8; |
|
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240 | our $POOL_RSS = 16 * 1024; |
|
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241 | our @async_pool; |
|
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242 | |
|
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243 | sub pool_handler { |
|
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244 | my $cb; |
|
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245 | |
|
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246 | while () { |
|
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247 | eval { |
|
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248 | while () { |
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249 | _pool_1 $cb; |
|
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250 | &$cb; |
|
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251 | _pool_2 $cb; |
|
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252 | &schedule; |
|
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253 | } |
|
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254 | }; |
|
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255 | |
|
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256 | last if $@ eq "\3terminate\2\n"; |
|
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257 | warn $@ if $@; |
|
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258 | } |
|
|
259 | } |
|
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260 | |
|
|
261 | sub async_pool(&@) { |
|
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262 | # this is also inlined into the unlock_scheduler |
|
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263 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
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264 | |
|
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265 | $coro->{_invoke} = [@_]; |
|
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266 | $coro->ready; |
|
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267 | |
|
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268 | $coro |
169 | } |
269 | } |
170 | |
270 | |
171 | =item schedule |
271 | =item schedule |
172 | |
272 | |
173 | Calls the scheduler. Please note that the current process will not be put |
273 | Calls the scheduler. Please note that the current coroutine will not be put |
174 | into the ready queue, so calling this function usually means you will |
274 | into the ready queue, so calling this function usually means you will |
175 | never be called again. |
275 | never be called again unless something else (e.g. an event handler) calls |
|
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276 | ready. |
176 | |
277 | |
177 | =cut |
278 | The canonical way to wait on external events is this: |
|
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279 | |
|
|
280 | { |
|
|
281 | # remember current coroutine |
|
|
282 | my $current = $Coro::current; |
|
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283 | |
|
|
284 | # register a hypothetical event handler |
|
|
285 | on_event_invoke sub { |
|
|
286 | # wake up sleeping coroutine |
|
|
287 | $current->ready; |
|
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288 | undef $current; |
|
|
289 | }; |
|
|
290 | |
|
|
291 | # call schedule until event occurred. |
|
|
292 | # in case we are woken up for other reasons |
|
|
293 | # (current still defined), loop. |
|
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294 | Coro::schedule while $current; |
|
|
295 | } |
178 | |
296 | |
179 | =item cede |
297 | =item cede |
180 | |
298 | |
181 | "Cede" to other processes. This function puts the current process into the |
299 | "Cede" to other coroutines. This function puts the current coroutine into the |
182 | ready queue and calls C<schedule>, which has the effect of giving up the |
300 | ready queue and calls C<schedule>, which has the effect of giving up the |
183 | current "timeslice" to other coroutines of the same or higher priority. |
301 | current "timeslice" to other coroutines of the same or higher priority. |
184 | |
302 | |
185 | =cut |
303 | Returns true if at least one coroutine switch has happened. |
|
|
304 | |
|
|
305 | =item Coro::cede_notself |
|
|
306 | |
|
|
307 | Works like cede, but is not exported by default and will cede to any |
|
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308 | coroutine, regardless of priority, once. |
|
|
309 | |
|
|
310 | Returns true if at least one coroutine switch has happened. |
186 | |
311 | |
187 | =item terminate [arg...] |
312 | =item terminate [arg...] |
188 | |
313 | |
189 | Terminates the current process. |
314 | Terminates the current coroutine with the given status values (see L<cancel>). |
190 | |
315 | |
191 | Future versions of this function will allow result arguments. |
316 | =item killall |
|
|
317 | |
|
|
318 | Kills/terminates/cancels all coroutines except the currently running |
|
|
319 | one. This is useful after a fork, either in the child or the parent, as |
|
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320 | usually only one of them should inherit the running coroutines. |
192 | |
321 | |
193 | =cut |
322 | =cut |
194 | |
323 | |
195 | sub terminate { |
324 | sub terminate { |
196 | $current->{status} = [@_]; |
|
|
197 | $current->cancel; |
325 | $current->cancel (@_); |
198 | &schedule; |
326 | } |
199 | die; # NORETURN |
327 | |
|
|
328 | sub killall { |
|
|
329 | for (Coro::State::list) { |
|
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330 | $_->cancel |
|
|
331 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
|
|
332 | } |
200 | } |
333 | } |
201 | |
334 | |
202 | =back |
335 | =back |
203 | |
336 | |
204 | # dynamic methods |
337 | # dynamic methods |
205 | |
338 | |
206 | =head2 PROCESS METHODS |
339 | =head2 COROUTINE METHODS |
207 | |
340 | |
208 | These are the methods you can call on process objects. |
341 | These are the methods you can call on coroutine objects. |
209 | |
342 | |
210 | =over 4 |
343 | =over 4 |
211 | |
344 | |
212 | =item new Coro \&sub [, @args...] |
345 | =item new Coro \&sub [, @args...] |
213 | |
346 | |
214 | Create a new process and return it. When the sub returns the process |
347 | Create a new coroutine and return it. When the sub returns the coroutine |
215 | automatically terminates as if C<terminate> with the returned values were |
348 | automatically terminates as if C<terminate> with the returned values were |
216 | called. To make the process run you must first put it into the ready queue |
349 | called. To make the coroutine run you must first put it into the ready queue |
217 | by calling the ready method. |
350 | by calling the ready method. |
218 | |
351 | |
219 | =cut |
352 | See C<async> and C<Coro::State::new> for additional info about the |
|
|
353 | coroutine environment. |
220 | |
354 | |
|
|
355 | =cut |
|
|
356 | |
221 | sub _newcoro { |
357 | sub _run_coro { |
222 | terminate &{+shift}; |
358 | terminate &{+shift}; |
223 | } |
359 | } |
224 | |
360 | |
225 | sub new { |
361 | sub new { |
226 | my $class = shift; |
362 | my $class = shift; |
227 | bless { |
|
|
228 | _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), |
|
|
229 | }, $class; |
|
|
230 | } |
|
|
231 | |
363 | |
232 | =item $process->ready |
364 | $class->SUPER::new (\&_run_coro, @_) |
|
|
365 | } |
233 | |
366 | |
234 | Put the given process into the ready queue. |
367 | =item $success = $coroutine->ready |
235 | |
368 | |
236 | =cut |
369 | Put the given coroutine into the ready queue (according to it's priority) |
|
|
370 | and return true. If the coroutine is already in the ready queue, do nothing |
|
|
371 | and return false. |
237 | |
372 | |
238 | =item $process->cancel |
373 | =item $is_ready = $coroutine->is_ready |
239 | |
374 | |
240 | Like C<terminate>, but terminates the specified process instead. |
375 | Return wether the coroutine is currently the ready queue or not, |
|
|
376 | |
|
|
377 | =item $coroutine->cancel (arg...) |
|
|
378 | |
|
|
379 | Terminates the given coroutine and makes it return the given arguments as |
|
|
380 | status (default: the empty list). Never returns if the coroutine is the |
|
|
381 | current coroutine. |
241 | |
382 | |
242 | =cut |
383 | =cut |
243 | |
384 | |
244 | sub cancel { |
385 | sub cancel { |
|
|
386 | my $self = shift; |
|
|
387 | $self->{_status} = [@_]; |
|
|
388 | |
|
|
389 | if ($current == $self) { |
245 | push @destroy, $_[0]; |
390 | push @destroy, $self; |
246 | $manager->ready; |
391 | $manager->ready; |
247 | &schedule if $current == $_[0]; |
392 | &schedule while 1; |
|
|
393 | } else { |
|
|
394 | $self->_cancel; |
|
|
395 | } |
248 | } |
396 | } |
249 | |
397 | |
250 | =item $process->join |
398 | =item $coroutine->join |
251 | |
399 | |
252 | Wait until the coroutine terminates and return any values given to the |
400 | Wait until the coroutine terminates and return any values given to the |
253 | C<terminate> function. C<join> can be called multiple times from multiple |
401 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
254 | processes. |
402 | from multiple coroutines. |
255 | |
403 | |
256 | =cut |
404 | =cut |
257 | |
405 | |
258 | sub join { |
406 | sub join { |
259 | my $self = shift; |
407 | my $self = shift; |
|
|
408 | |
260 | unless ($self->{status}) { |
409 | unless ($self->{_status}) { |
261 | push @{$self->{join}}, $current; |
410 | my $current = $current; |
262 | &schedule; |
411 | |
|
|
412 | push @{$self->{_on_destroy}}, sub { |
|
|
413 | $current->ready; |
|
|
414 | undef $current; |
|
|
415 | }; |
|
|
416 | |
|
|
417 | &schedule while $current; |
263 | } |
418 | } |
|
|
419 | |
264 | wantarray ? @{$self->{status}} : $self->{status}[0]; |
420 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
265 | } |
421 | } |
266 | |
422 | |
|
|
423 | =item $coroutine->on_destroy (\&cb) |
|
|
424 | |
|
|
425 | Registers a callback that is called when this coroutine gets destroyed, |
|
|
426 | but before it is joined. The callback gets passed the terminate arguments, |
|
|
427 | if any. |
|
|
428 | |
|
|
429 | =cut |
|
|
430 | |
|
|
431 | sub on_destroy { |
|
|
432 | my ($self, $cb) = @_; |
|
|
433 | |
|
|
434 | push @{ $self->{_on_destroy} }, $cb; |
|
|
435 | } |
|
|
436 | |
267 | =item $oldprio = $process->prio($newprio) |
437 | =item $oldprio = $coroutine->prio ($newprio) |
268 | |
438 | |
269 | Sets (or gets, if the argument is missing) the priority of the |
439 | Sets (or gets, if the argument is missing) the priority of the |
270 | process. Higher priority processes get run before lower priority |
440 | coroutine. Higher priority coroutines get run before lower priority |
271 | processes. Priorities are small signed integers (currently -4 .. +3), |
441 | coroutines. Priorities are small signed integers (currently -4 .. +3), |
272 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
442 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
273 | to get then): |
443 | to get then): |
274 | |
444 | |
275 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
445 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
276 | 3 > 1 > 0 > -1 > -3 > -4 |
446 | 3 > 1 > 0 > -1 > -3 > -4 |
… | |
… | |
279 | current->prio(PRIO_HIGH); |
449 | current->prio(PRIO_HIGH); |
280 | |
450 | |
281 | The idle coroutine ($Coro::idle) always has a lower priority than any |
451 | The idle coroutine ($Coro::idle) always has a lower priority than any |
282 | existing coroutine. |
452 | existing coroutine. |
283 | |
453 | |
284 | Changing the priority of the current process will take effect immediately, |
454 | Changing the priority of the current coroutine will take effect immediately, |
285 | but changing the priority of processes in the ready queue (but not |
455 | but changing the priority of coroutines in the ready queue (but not |
286 | running) will only take effect after the next schedule (of that |
456 | running) will only take effect after the next schedule (of that |
287 | process). This is a bug that will be fixed in some future version. |
457 | coroutine). This is a bug that will be fixed in some future version. |
288 | |
458 | |
289 | =cut |
|
|
290 | |
|
|
291 | sub prio { |
|
|
292 | my $old = $_[0]{prio}; |
|
|
293 | $_[0]{prio} = $_[1] if @_ > 1; |
|
|
294 | $old; |
|
|
295 | } |
|
|
296 | |
|
|
297 | =item $newprio = $process->nice($change) |
459 | =item $newprio = $coroutine->nice ($change) |
298 | |
460 | |
299 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
461 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
300 | higher values mean lower priority, just as in unix). |
462 | higher values mean lower priority, just as in unix). |
301 | |
463 | |
302 | =cut |
|
|
303 | |
|
|
304 | sub nice { |
|
|
305 | $_[0]{prio} -= $_[1]; |
|
|
306 | } |
|
|
307 | |
|
|
308 | =item $olddesc = $process->desc($newdesc) |
464 | =item $olddesc = $coroutine->desc ($newdesc) |
309 | |
465 | |
310 | Sets (or gets in case the argument is missing) the description for this |
466 | Sets (or gets in case the argument is missing) the description for this |
311 | process. This is just a free-form string you can associate with a process. |
467 | coroutine. This is just a free-form string you can associate with a coroutine. |
|
|
468 | |
|
|
469 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
|
|
470 | can modify this member directly if you wish. |
312 | |
471 | |
313 | =cut |
472 | =cut |
314 | |
473 | |
315 | sub desc { |
474 | sub desc { |
316 | my $old = $_[0]{desc}; |
475 | my $old = $_[0]{desc}; |
… | |
… | |
318 | $old; |
477 | $old; |
319 | } |
478 | } |
320 | |
479 | |
321 | =back |
480 | =back |
322 | |
481 | |
|
|
482 | =head2 GLOBAL FUNCTIONS |
|
|
483 | |
|
|
484 | =over 4 |
|
|
485 | |
|
|
486 | =item Coro::nready |
|
|
487 | |
|
|
488 | Returns the number of coroutines that are currently in the ready state, |
|
|
489 | i.e. that can be switched to. The value C<0> means that the only runnable |
|
|
490 | coroutine is the currently running one, so C<cede> would have no effect, |
|
|
491 | and C<schedule> would cause a deadlock unless there is an idle handler |
|
|
492 | that wakes up some coroutines. |
|
|
493 | |
|
|
494 | =item my $guard = Coro::guard { ... } |
|
|
495 | |
|
|
496 | This creates and returns a guard object. Nothing happens until the object |
|
|
497 | gets destroyed, in which case the codeblock given as argument will be |
|
|
498 | executed. This is useful to free locks or other resources in case of a |
|
|
499 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
500 | guard block will be executed. The guard object supports only one method, |
|
|
501 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
|
502 | |
|
|
503 | Example: set some flag and clear it again when the coroutine gets canceled |
|
|
504 | or the function returns: |
|
|
505 | |
|
|
506 | sub do_something { |
|
|
507 | my $guard = Coro::guard { $busy = 0 }; |
|
|
508 | $busy = 1; |
|
|
509 | |
|
|
510 | # do something that requires $busy to be true |
|
|
511 | } |
|
|
512 | |
|
|
513 | =cut |
|
|
514 | |
|
|
515 | sub guard(&) { |
|
|
516 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
517 | } |
|
|
518 | |
|
|
519 | sub Coro::guard::cancel { |
|
|
520 | ${$_[0]} = sub { }; |
|
|
521 | } |
|
|
522 | |
|
|
523 | sub Coro::guard::DESTROY { |
|
|
524 | ${$_[0]}->(); |
|
|
525 | } |
|
|
526 | |
|
|
527 | |
|
|
528 | =item unblock_sub { ... } |
|
|
529 | |
|
|
530 | This utility function takes a BLOCK or code reference and "unblocks" it, |
|
|
531 | returning the new coderef. This means that the new coderef will return |
|
|
532 | immediately without blocking, returning nothing, while the original code |
|
|
533 | ref will be called (with parameters) from within its own coroutine. |
|
|
534 | |
|
|
535 | The reason this function exists is that many event libraries (such as the |
|
|
536 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
|
|
537 | of thread-safety). This means you must not block within event callbacks, |
|
|
538 | otherwise you might suffer from crashes or worse. |
|
|
539 | |
|
|
540 | This function allows your callbacks to block by executing them in another |
|
|
541 | coroutine where it is safe to block. One example where blocking is handy |
|
|
542 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
|
|
543 | disk. |
|
|
544 | |
|
|
545 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
|
|
546 | creating event callbacks that want to block. |
|
|
547 | |
|
|
548 | =cut |
|
|
549 | |
|
|
550 | our @unblock_queue; |
|
|
551 | |
|
|
552 | # we create a special coro because we want to cede, |
|
|
553 | # to reduce pressure on the coro pool (because most callbacks |
|
|
554 | # return immediately and can be reused) and because we cannot cede |
|
|
555 | # inside an event callback. |
|
|
556 | our $unblock_scheduler = new Coro sub { |
|
|
557 | while () { |
|
|
558 | while (my $cb = pop @unblock_queue) { |
|
|
559 | # this is an inlined copy of async_pool |
|
|
560 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
561 | |
|
|
562 | $coro->{_invoke} = $cb; |
|
|
563 | $coro->ready; |
|
|
564 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
565 | } |
|
|
566 | schedule; # sleep well |
|
|
567 | } |
|
|
568 | }; |
|
|
569 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
|
|
570 | |
|
|
571 | sub unblock_sub(&) { |
|
|
572 | my $cb = shift; |
|
|
573 | |
|
|
574 | sub { |
|
|
575 | unshift @unblock_queue, [$cb, @_]; |
|
|
576 | $unblock_scheduler->ready; |
|
|
577 | } |
|
|
578 | } |
|
|
579 | |
|
|
580 | =back |
|
|
581 | |
323 | =cut |
582 | =cut |
324 | |
583 | |
325 | 1; |
584 | 1; |
326 | |
585 | |
327 | =head1 BUGS/LIMITATIONS |
586 | =head1 BUGS/LIMITATIONS |
328 | |
587 | |
329 | - you must make very sure that no coro is still active on global |
588 | - you must make very sure that no coro is still active on global |
330 | destruction. very bad things might happen otherwise (usually segfaults). |
589 | destruction. very bad things might happen otherwise (usually segfaults). |
331 | |
590 | |
332 | - this module is not thread-safe. You should only ever use this module |
591 | - this module is not thread-safe. You should only ever use this module |
333 | from the same thread (this requirement might be losened in the future |
592 | from the same thread (this requirement might be loosened in the future |
334 | to allow per-thread schedulers, but Coro::State does not yet allow |
593 | to allow per-thread schedulers, but Coro::State does not yet allow |
335 | this). |
594 | this). |
336 | |
595 | |
337 | =head1 SEE ALSO |
596 | =head1 SEE ALSO |
338 | |
597 | |
339 | L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
598 | Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
340 | L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>, |
599 | |
341 | L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>. |
600 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
|
|
601 | |
|
|
602 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
|
|
603 | |
|
|
604 | Embedding: L<Coro:MakeMaker> |
342 | |
605 | |
343 | =head1 AUTHOR |
606 | =head1 AUTHOR |
344 | |
607 | |
345 | Marc Lehmann <pcg@goof.com> |
608 | Marc Lehmann <schmorp@schmorp.de> |
346 | http://www.goof.com/pcg/marc/ |
609 | http://home.schmorp.de/ |
347 | |
610 | |
348 | =cut |
611 | =cut |
349 | |
612 | |