… | |
… | |
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 | |
|
|
44 | use strict; |
35 | no warnings qw(uninitialized); |
45 | no warnings "uninitialized"; |
36 | |
46 | |
37 | use Coro::State; |
47 | use Coro::State; |
38 | |
48 | |
39 | use base Exporter; |
49 | use base qw(Coro::State Exporter); |
40 | |
50 | |
41 | $VERSION = 0.6; |
51 | our $idle; # idle handler |
|
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52 | our $main; # main coroutine |
|
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53 | our $current; # current coroutine |
42 | |
54 | |
|
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55 | our $VERSION = '4.02'; |
|
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56 | |
43 | @EXPORT = qw(async cede schedule terminate current); |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
44 | %EXPORT_TAGS = ( |
58 | our %EXPORT_TAGS = ( |
45 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
46 | ); |
60 | ); |
47 | @EXPORT_OK = @{$EXPORT_TAGS{prio}}; |
61 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
48 | |
62 | |
49 | { |
63 | { |
50 | my @async; |
64 | my @async; |
51 | my $init; |
65 | my $init; |
52 | |
66 | |
53 | # this way of handling attributes simply is NOT scalable ;() |
67 | # this way of handling attributes simply is NOT scalable ;() |
54 | sub import { |
68 | sub import { |
|
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69 | no strict 'refs'; |
|
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70 | |
55 | Coro->export_to_level(1, @_); |
71 | Coro->export_to_level (1, @_); |
|
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72 | |
56 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
73 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
57 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
74 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
58 | my ($package, $ref) = (shift, shift); |
75 | my ($package, $ref) = (shift, shift); |
59 | my @attrs; |
76 | my @attrs; |
60 | for (@_) { |
77 | for (@_) { |
… | |
… | |
83 | |
100 | |
84 | This coroutine represents the main program. |
101 | This coroutine represents the main program. |
85 | |
102 | |
86 | =cut |
103 | =cut |
87 | |
104 | |
88 | our $main = new Coro; |
105 | $main = new Coro; |
89 | |
106 | |
90 | =item $current (or as function: current) |
107 | =item $current (or as function: current) |
91 | |
108 | |
92 | The current coroutine (the last coroutine switched to). The initial value is C<$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). |
93 | |
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 | |
94 | =cut |
116 | =cut |
|
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117 | |
|
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118 | $main->{desc} = "[main::]"; |
95 | |
119 | |
96 | # maybe some other module used Coro::Specific before... |
120 | # maybe some other module used Coro::Specific before... |
97 | if ($current) { |
|
|
98 | $main->{specific} = $current->{specific}; |
121 | $main->{_specific} = $current->{_specific} |
99 | } |
122 | if $current; |
100 | |
123 | |
101 | our $current = $main; |
124 | _set_current $main; |
102 | |
125 | |
103 | sub current() { $current } |
126 | sub current() { $current } |
104 | |
127 | |
105 | =item $idle |
128 | =item $idle |
106 | |
129 | |
107 | 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 |
108 | 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. |
109 | |
133 | |
110 | =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. |
111 | |
137 | |
112 | # should be done using priorities :( |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
113 | our $idle = new Coro sub { |
139 | handlers), then it must be prepared to be called recursively. |
114 | print STDERR "FATAL: deadlock detected\n"; |
140 | |
115 | exit(51); |
141 | =cut |
|
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142 | |
|
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143 | $idle = sub { |
|
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144 | require Carp; |
|
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145 | Carp::croak ("FATAL: deadlock detected"); |
116 | }; |
146 | }; |
|
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147 | |
|
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148 | sub _cancel { |
|
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149 | my ($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 | } |
117 | |
159 | |
118 | # this coroutine is necessary because a coroutine |
160 | # this coroutine is necessary because a coroutine |
119 | # cannot destroy itself. |
161 | # cannot destroy itself. |
120 | my @destroy; |
162 | my @destroy; |
121 | my $manager; |
163 | my $manager; |
|
|
164 | |
122 | $manager = new Coro sub { |
165 | $manager = new Coro sub { |
123 | while() { |
166 | while () { |
124 | # by overwriting the state object with the manager we destroy it |
167 | (shift @destroy)->_cancel |
125 | # while still being able to schedule this coroutine (in case it has |
|
|
126 | # been readied multiple times. this is harmless since the manager |
|
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127 | # can be called as many times as neccessary and will always |
|
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128 | # remove itself from the runqueue |
|
|
129 | while (@destroy) { |
168 | while @destroy; |
130 | my $coro = pop @destroy; |
169 | |
131 | $coro->{status} ||= []; |
|
|
132 | $_->ready for @{delete $coro->{join} || []}; |
|
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133 | $coro->{_coro_state} = $manager->{_coro_state}; |
|
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134 | } |
|
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135 | &schedule; |
170 | &schedule; |
136 | } |
171 | } |
137 | }; |
172 | }; |
|
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173 | $manager->desc ("[coro manager]"); |
|
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174 | $manager->prio (PRIO_MAX); |
138 | |
175 | |
139 | # static methods. not really. |
176 | # static methods. not really. |
140 | |
177 | |
141 | =back |
178 | =back |
142 | |
179 | |
143 | =head2 STATIC METHODS |
180 | =head2 STATIC METHODS |
144 | |
181 | |
145 | 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. |
146 | |
183 | |
147 | =over 4 |
184 | =over 4 |
148 | |
185 | |
149 | =item async { ... } [@args...] |
186 | =item async { ... } [@args...] |
150 | |
187 | |
151 | Create a new asynchronous process and return it's process object |
188 | Create a new asynchronous coroutine and return it's coroutine object |
152 | (usually unused). When the sub returns the new process is automatically |
189 | (usually unused). When the sub returns the new coroutine is automatically |
153 | 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. |
154 | |
198 | |
155 | # create a new coroutine that just prints its arguments |
199 | # create a new coroutine that just prints its arguments |
156 | async { |
200 | async { |
157 | print "@_\n"; |
201 | print "@_\n"; |
158 | } 1,2,3,4; |
202 | } 1,2,3,4; |
159 | |
203 | |
160 | The coderef you submit MUST NOT be a closure that refers to variables |
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161 | in an outer scope. This does NOT work. Pass arguments into it instead. |
|
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162 | |
|
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163 | =cut |
204 | =cut |
164 | |
205 | |
165 | sub async(&@) { |
206 | sub async(&@) { |
166 | my $pid = new Coro @_; |
207 | my $coro = new Coro @_; |
167 | $manager->ready; # this ensures that the stack is cloned from the manager |
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168 | $pid->ready; |
208 | $coro->ready; |
169 | $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, tracing will be |
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225 | disabled, the description will be reset and the default output filehandle |
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226 | gets restored, so you can change alkl these. Otherwise the coroutine will |
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227 | be re-used "as-is": most notably if you change other per-coroutine global |
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228 | stuff such as C<$/> you need to revert that change, which is most simply |
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229 | done by using local as in C< local $/ >. |
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230 | |
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231 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
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232 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
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233 | required. |
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234 | |
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235 | If you are concerned about pooled coroutines growing a lot because a |
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236 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
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237 | { terminate }> once per second or so to slowly replenish the pool. In |
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238 | addition to that, when the stacks used by a handler grows larger than 16kb |
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239 | (adjustable with $Coro::POOL_RSS) it will also exit. |
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240 | |
|
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241 | =cut |
|
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242 | |
|
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243 | our $POOL_SIZE = 8; |
|
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244 | our $POOL_RSS = 16 * 1024; |
|
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245 | our @async_pool; |
|
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246 | |
|
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247 | sub pool_handler { |
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248 | my $cb; |
|
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249 | |
|
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250 | while () { |
|
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251 | eval { |
|
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252 | while () { |
|
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253 | _pool_1 $cb; |
|
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254 | &$cb; |
|
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255 | _pool_2 $cb; |
|
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256 | &schedule; |
|
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257 | } |
|
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258 | }; |
|
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259 | |
|
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260 | last if $@ eq "\3terminate\2\n"; |
|
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261 | warn $@ if $@; |
|
|
262 | } |
|
|
263 | } |
|
|
264 | |
|
|
265 | sub async_pool(&@) { |
|
|
266 | # this is also inlined into the unlock_scheduler |
|
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267 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
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268 | |
|
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269 | $coro->{_invoke} = [@_]; |
|
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270 | $coro->ready; |
|
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271 | |
|
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272 | $coro |
170 | } |
273 | } |
171 | |
274 | |
172 | =item schedule |
275 | =item schedule |
173 | |
276 | |
174 | Calls the scheduler. Please note that the current process will not be put |
277 | Calls the scheduler. Please note that the current coroutine will not be put |
175 | into the ready queue, so calling this function usually means you will |
278 | into the ready queue, so calling this function usually means you will |
176 | never be called again. |
279 | never be called again unless something else (e.g. an event handler) calls |
|
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280 | ready. |
177 | |
281 | |
178 | =cut |
282 | The canonical way to wait on external events is this: |
|
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283 | |
|
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284 | { |
|
|
285 | # remember current coroutine |
|
|
286 | my $current = $Coro::current; |
|
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287 | |
|
|
288 | # register a hypothetical event handler |
|
|
289 | on_event_invoke sub { |
|
|
290 | # wake up sleeping coroutine |
|
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291 | $current->ready; |
|
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292 | undef $current; |
|
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293 | }; |
|
|
294 | |
|
|
295 | # call schedule until event occurred. |
|
|
296 | # in case we are woken up for other reasons |
|
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297 | # (current still defined), loop. |
|
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298 | Coro::schedule while $current; |
|
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299 | } |
179 | |
300 | |
180 | =item cede |
301 | =item cede |
181 | |
302 | |
182 | "Cede" to other processes. This function puts the current process into the |
303 | "Cede" to other coroutines. This function puts the current coroutine into the |
183 | ready queue and calls C<schedule>, which has the effect of giving up the |
304 | ready queue and calls C<schedule>, which has the effect of giving up the |
184 | current "timeslice" to other coroutines of the same or higher priority. |
305 | current "timeslice" to other coroutines of the same or higher priority. |
185 | |
306 | |
186 | =cut |
307 | Returns true if at least one coroutine switch has happened. |
|
|
308 | |
|
|
309 | =item Coro::cede_notself |
|
|
310 | |
|
|
311 | Works like cede, but is not exported by default and will cede to any |
|
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312 | coroutine, regardless of priority, once. |
|
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313 | |
|
|
314 | Returns true if at least one coroutine switch has happened. |
187 | |
315 | |
188 | =item terminate [arg...] |
316 | =item terminate [arg...] |
189 | |
317 | |
190 | Terminates the current process. |
318 | Terminates the current coroutine with the given status values (see L<cancel>). |
191 | |
319 | |
192 | Future versions of this function will allow result arguments. |
320 | =item killall |
|
|
321 | |
|
|
322 | Kills/terminates/cancels all coroutines except the currently running |
|
|
323 | one. This is useful after a fork, either in the child or the parent, as |
|
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324 | usually only one of them should inherit the running coroutines. |
193 | |
325 | |
194 | =cut |
326 | =cut |
195 | |
327 | |
196 | sub terminate { |
328 | sub terminate { |
197 | $current->{status} = [@_]; |
|
|
198 | $current->cancel; |
329 | $current->cancel (@_); |
199 | &schedule; |
330 | } |
200 | die; # NORETURN |
331 | |
|
|
332 | sub killall { |
|
|
333 | for (Coro::State::list) { |
|
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334 | $_->cancel |
|
|
335 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
|
|
336 | } |
201 | } |
337 | } |
202 | |
338 | |
203 | =back |
339 | =back |
204 | |
340 | |
205 | # dynamic methods |
341 | # dynamic methods |
206 | |
342 | |
207 | =head2 PROCESS METHODS |
343 | =head2 COROUTINE METHODS |
208 | |
344 | |
209 | These are the methods you can call on process objects. |
345 | These are the methods you can call on coroutine objects. |
210 | |
346 | |
211 | =over 4 |
347 | =over 4 |
212 | |
348 | |
213 | =item new Coro \&sub [, @args...] |
349 | =item new Coro \&sub [, @args...] |
214 | |
350 | |
215 | Create a new process and return it. When the sub returns the process |
351 | Create a new coroutine and return it. When the sub returns the coroutine |
216 | automatically terminates as if C<terminate> with the returned values were |
352 | automatically terminates as if C<terminate> with the returned values were |
217 | called. To make the process run you must first put it into the ready queue |
353 | called. To make the coroutine run you must first put it into the ready queue |
218 | by calling the ready method. |
354 | by calling the ready method. |
219 | |
355 | |
220 | =cut |
356 | See C<async> and C<Coro::State::new> for additional info about the |
|
|
357 | coroutine environment. |
221 | |
358 | |
|
|
359 | =cut |
|
|
360 | |
222 | sub _newcoro { |
361 | sub _run_coro { |
223 | terminate &{+shift}; |
362 | terminate &{+shift}; |
224 | } |
363 | } |
225 | |
364 | |
226 | sub new { |
365 | sub new { |
227 | my $class = shift; |
366 | my $class = shift; |
228 | bless { |
|
|
229 | _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), |
|
|
230 | }, $class; |
|
|
231 | } |
|
|
232 | |
367 | |
233 | =item $process->ready |
368 | $class->SUPER::new (\&_run_coro, @_) |
|
|
369 | } |
234 | |
370 | |
235 | Put the given process into the ready queue. |
371 | =item $success = $coroutine->ready |
236 | |
372 | |
237 | =cut |
373 | Put the given coroutine into the ready queue (according to it's priority) |
|
|
374 | and return true. If the coroutine is already in the ready queue, do nothing |
|
|
375 | and return false. |
238 | |
376 | |
239 | =item $process->cancel |
377 | =item $is_ready = $coroutine->is_ready |
240 | |
378 | |
241 | Like C<terminate>, but terminates the specified process instead. |
379 | Return wether the coroutine is currently the ready queue or not, |
|
|
380 | |
|
|
381 | =item $coroutine->cancel (arg...) |
|
|
382 | |
|
|
383 | Terminates the given coroutine and makes it return the given arguments as |
|
|
384 | status (default: the empty list). Never returns if the coroutine is the |
|
|
385 | current coroutine. |
242 | |
386 | |
243 | =cut |
387 | =cut |
244 | |
388 | |
245 | sub cancel { |
389 | sub cancel { |
|
|
390 | my $self = shift; |
|
|
391 | $self->{_status} = [@_]; |
|
|
392 | |
|
|
393 | if ($current == $self) { |
246 | push @destroy, $_[0]; |
394 | push @destroy, $self; |
247 | $manager->ready; |
395 | $manager->ready; |
248 | &schedule if $current == $_[0]; |
396 | &schedule while 1; |
|
|
397 | } else { |
|
|
398 | $self->_cancel; |
|
|
399 | } |
249 | } |
400 | } |
250 | |
401 | |
251 | =item $process->join |
402 | =item $coroutine->join |
252 | |
403 | |
253 | Wait until the coroutine terminates and return any values given to the |
404 | Wait until the coroutine terminates and return any values given to the |
254 | C<terminate> function. C<join> can be called multiple times from multiple |
405 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
255 | processes. |
406 | from multiple coroutines. |
256 | |
407 | |
257 | =cut |
408 | =cut |
258 | |
409 | |
259 | sub join { |
410 | sub join { |
260 | my $self = shift; |
411 | my $self = shift; |
|
|
412 | |
261 | unless ($self->{status}) { |
413 | unless ($self->{_status}) { |
262 | push @{$self->{join}}, $current; |
414 | my $current = $current; |
263 | &schedule; |
415 | |
|
|
416 | push @{$self->{_on_destroy}}, sub { |
|
|
417 | $current->ready; |
|
|
418 | undef $current; |
|
|
419 | }; |
|
|
420 | |
|
|
421 | &schedule while $current; |
264 | } |
422 | } |
|
|
423 | |
265 | wantarray ? @{$self->{status}} : $self->{status}[0]; |
424 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
266 | } |
425 | } |
267 | |
426 | |
|
|
427 | =item $coroutine->on_destroy (\&cb) |
|
|
428 | |
|
|
429 | Registers a callback that is called when this coroutine gets destroyed, |
|
|
430 | but before it is joined. The callback gets passed the terminate arguments, |
|
|
431 | if any. |
|
|
432 | |
|
|
433 | =cut |
|
|
434 | |
|
|
435 | sub on_destroy { |
|
|
436 | my ($self, $cb) = @_; |
|
|
437 | |
|
|
438 | push @{ $self->{_on_destroy} }, $cb; |
|
|
439 | } |
|
|
440 | |
268 | =item $oldprio = $process->prio($newprio) |
441 | =item $oldprio = $coroutine->prio ($newprio) |
269 | |
442 | |
270 | Sets (or gets, if the argument is missing) the priority of the |
443 | Sets (or gets, if the argument is missing) the priority of the |
271 | process. Higher priority processes get run before lower priority |
444 | coroutine. Higher priority coroutines get run before lower priority |
272 | processes. Priorities are smalled signed integer (currently -4 .. +3), |
445 | coroutines. Priorities are small signed integers (currently -4 .. +3), |
273 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
446 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
274 | to get then): |
447 | to get then): |
275 | |
448 | |
276 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
449 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
277 | 3 > 1 > 0 > -1 > -3 > -4 |
450 | 3 > 1 > 0 > -1 > -3 > -4 |
… | |
… | |
280 | current->prio(PRIO_HIGH); |
453 | current->prio(PRIO_HIGH); |
281 | |
454 | |
282 | The idle coroutine ($Coro::idle) always has a lower priority than any |
455 | The idle coroutine ($Coro::idle) always has a lower priority than any |
283 | existing coroutine. |
456 | existing coroutine. |
284 | |
457 | |
285 | Changing the priority of the current process will take effect immediately, |
458 | Changing the priority of the current coroutine will take effect immediately, |
286 | but changing the priority of processes in the ready queue (but not |
459 | but changing the priority of coroutines in the ready queue (but not |
287 | running) will only take effect after the next schedule (of that |
460 | running) will only take effect after the next schedule (of that |
288 | process). This is a bug that will be fixed in some future version. |
461 | coroutine). This is a bug that will be fixed in some future version. |
289 | |
462 | |
290 | =cut |
|
|
291 | |
|
|
292 | sub prio { |
|
|
293 | my $old = $_[0]{prio}; |
|
|
294 | $_[0]{prio} = $_[1] if @_ > 1; |
|
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295 | $old; |
|
|
296 | } |
|
|
297 | |
|
|
298 | =item $newprio = $process->nice($change) |
463 | =item $newprio = $coroutine->nice ($change) |
299 | |
464 | |
300 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
465 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
301 | higher values mean lower priority, just as in unix). |
466 | higher values mean lower priority, just as in unix). |
302 | |
467 | |
303 | =cut |
|
|
304 | |
|
|
305 | sub nice { |
|
|
306 | $_[0]{prio} -= $_[1]; |
|
|
307 | } |
|
|
308 | |
|
|
309 | =item $olddesc = $process->desc($newdesc) |
468 | =item $olddesc = $coroutine->desc ($newdesc) |
310 | |
469 | |
311 | Sets (or gets in case the argument is missing) the description for this |
470 | Sets (or gets in case the argument is missing) the description for this |
312 | process. This is just a free-form string you can associate with a process. |
471 | coroutine. This is just a free-form string you can associate with a coroutine. |
|
|
472 | |
|
|
473 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
|
|
474 | can modify this member directly if you wish. |
313 | |
475 | |
314 | =cut |
476 | =cut |
315 | |
477 | |
316 | sub desc { |
478 | sub desc { |
317 | my $old = $_[0]{desc}; |
479 | my $old = $_[0]{desc}; |
… | |
… | |
319 | $old; |
481 | $old; |
320 | } |
482 | } |
321 | |
483 | |
322 | =back |
484 | =back |
323 | |
485 | |
|
|
486 | =head2 GLOBAL FUNCTIONS |
|
|
487 | |
|
|
488 | =over 4 |
|
|
489 | |
|
|
490 | =item Coro::nready |
|
|
491 | |
|
|
492 | Returns the number of coroutines that are currently in the ready state, |
|
|
493 | i.e. that can be switched to. The value C<0> means that the only runnable |
|
|
494 | coroutine is the currently running one, so C<cede> would have no effect, |
|
|
495 | and C<schedule> would cause a deadlock unless there is an idle handler |
|
|
496 | that wakes up some coroutines. |
|
|
497 | |
|
|
498 | =item my $guard = Coro::guard { ... } |
|
|
499 | |
|
|
500 | This creates and returns a guard object. Nothing happens until the object |
|
|
501 | gets destroyed, in which case the codeblock given as argument will be |
|
|
502 | executed. This is useful to free locks or other resources in case of a |
|
|
503 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
504 | guard block will be executed. The guard object supports only one method, |
|
|
505 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
|
506 | |
|
|
507 | Example: set some flag and clear it again when the coroutine gets canceled |
|
|
508 | or the function returns: |
|
|
509 | |
|
|
510 | sub do_something { |
|
|
511 | my $guard = Coro::guard { $busy = 0 }; |
|
|
512 | $busy = 1; |
|
|
513 | |
|
|
514 | # do something that requires $busy to be true |
|
|
515 | } |
|
|
516 | |
|
|
517 | =cut |
|
|
518 | |
|
|
519 | sub guard(&) { |
|
|
520 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
521 | } |
|
|
522 | |
|
|
523 | sub Coro::guard::cancel { |
|
|
524 | ${$_[0]} = sub { }; |
|
|
525 | } |
|
|
526 | |
|
|
527 | sub Coro::guard::DESTROY { |
|
|
528 | ${$_[0]}->(); |
|
|
529 | } |
|
|
530 | |
|
|
531 | |
|
|
532 | =item unblock_sub { ... } |
|
|
533 | |
|
|
534 | This utility function takes a BLOCK or code reference and "unblocks" it, |
|
|
535 | returning the new coderef. This means that the new coderef will return |
|
|
536 | immediately without blocking, returning nothing, while the original code |
|
|
537 | ref will be called (with parameters) from within its own coroutine. |
|
|
538 | |
|
|
539 | The reason this function exists is that many event libraries (such as the |
|
|
540 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
|
|
541 | of thread-safety). This means you must not block within event callbacks, |
|
|
542 | otherwise you might suffer from crashes or worse. |
|
|
543 | |
|
|
544 | This function allows your callbacks to block by executing them in another |
|
|
545 | coroutine where it is safe to block. One example where blocking is handy |
|
|
546 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
|
|
547 | disk. |
|
|
548 | |
|
|
549 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
|
|
550 | creating event callbacks that want to block. |
|
|
551 | |
|
|
552 | =cut |
|
|
553 | |
|
|
554 | our @unblock_queue; |
|
|
555 | |
|
|
556 | # we create a special coro because we want to cede, |
|
|
557 | # to reduce pressure on the coro pool (because most callbacks |
|
|
558 | # return immediately and can be reused) and because we cannot cede |
|
|
559 | # inside an event callback. |
|
|
560 | our $unblock_scheduler = new Coro sub { |
|
|
561 | while () { |
|
|
562 | while (my $cb = pop @unblock_queue) { |
|
|
563 | # this is an inlined copy of async_pool |
|
|
564 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
565 | |
|
|
566 | $coro->{_invoke} = $cb; |
|
|
567 | $coro->ready; |
|
|
568 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
569 | } |
|
|
570 | schedule; # sleep well |
|
|
571 | } |
|
|
572 | }; |
|
|
573 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
|
|
574 | |
|
|
575 | sub unblock_sub(&) { |
|
|
576 | my $cb = shift; |
|
|
577 | |
|
|
578 | sub { |
|
|
579 | unshift @unblock_queue, [$cb, @_]; |
|
|
580 | $unblock_scheduler->ready; |
|
|
581 | } |
|
|
582 | } |
|
|
583 | |
|
|
584 | =back |
|
|
585 | |
324 | =cut |
586 | =cut |
325 | |
587 | |
326 | 1; |
588 | 1; |
327 | |
589 | |
328 | =head1 BUGS/LIMITATIONS |
590 | =head1 BUGS/LIMITATIONS |
329 | |
591 | |
330 | - you must make very sure that no coro is still active on global destruction. |
592 | - you must make very sure that no coro is still active on global |
331 | very bad things might happen otherwise (usually segfaults). |
593 | destruction. very bad things might happen otherwise (usually segfaults). |
|
|
594 | |
332 | - this module is not thread-safe. You should only ever use this module from |
595 | - this module is not thread-safe. You should only ever use this module |
333 | the same thread (this requirement might be loosened in the future to |
596 | from the same thread (this requirement might be loosened in the future |
334 | allow per-thread schedulers, but Coro::State does not yet allow this). |
597 | to allow per-thread schedulers, but Coro::State does not yet allow |
|
|
598 | this). |
335 | |
599 | |
336 | =head1 SEE ALSO |
600 | =head1 SEE ALSO |
337 | |
601 | |
338 | L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
602 | Support/Utility: L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
339 | L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, |
603 | |
340 | L<Coro::Handle>, L<Coro::Socket>. |
604 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
|
|
605 | |
|
|
606 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
|
|
607 | |
|
|
608 | Embedding: L<Coro:MakeMaker> |
341 | |
609 | |
342 | =head1 AUTHOR |
610 | =head1 AUTHOR |
343 | |
611 | |
344 | Marc Lehmann <pcg@goof.com> |
612 | Marc Lehmann <schmorp@schmorp.de> |
345 | http://www.goof.com/pcg/marc/ |
613 | http://home.schmorp.de/ |
346 | |
614 | |
347 | =cut |
615 | =cut |
348 | |
616 | |