… | |
… | |
8 | |
8 | |
9 | my $loop = EV::Loop::Async::default; |
9 | my $loop = EV::Loop::Async::default; |
10 | my $timer; |
10 | my $timer; |
11 | my $flag; |
11 | my $flag; |
12 | |
12 | |
|
|
13 | # create a watcher, but make sure the loop is locked |
13 | { |
14 | { |
14 | $loop->scope_lock; # lock the loop structures |
15 | $loop->scope_lock; # lock the loop structures |
15 | $timer = $loop->timer (5, 1, sub { $flag = 1 }); |
16 | $timer = $loop->timer (5, 1, sub { $flag = 1 }); |
16 | $loop->nudge; # tell loop to take note of the timer |
17 | $loop->notify; # tell loop to take note of the timer |
17 | } |
18 | } |
18 | |
19 | |
19 | 1 while $flag; # $flag will be set asynchronously |
20 | 1 while $flag; # $flag will be set asynchronously |
20 | |
21 | |
|
|
22 | # implement a critical section, uninterrupted by any callbacks |
21 | { |
23 | { |
22 | $loop->interrupt->scope_block; |
24 | $loop->interrupt->scope_block; |
23 | # critical section, no watcher callback interruptions |
25 | # critical section, no watcher callback interruptions |
24 | } |
26 | } |
25 | |
27 | |
26 | # stop timer again |
28 | # stop the timer watcher again - locking is required once more |
27 | |
|
|
28 | { |
29 | { |
29 | $loop->scope_lock; # lock the loop structures |
30 | $loop->scope_lock; # lock the loop structures |
30 | $timer->stop; |
31 | $timer->stop; |
31 | # no need to nudge |
32 | # no need to notify |
32 | } |
33 | } |
33 | |
34 | |
34 | =head1 DESCRIPTION |
35 | =head1 DESCRIPTION |
35 | |
36 | |
36 | This module implements a rather specialised event loop - it takes a normal |
37 | This module implements a rather specialised event loop - it takes a normal |
… | |
… | |
45 | See the documentation for L<Async::Interrupt> for details on when and how |
46 | See the documentation for L<Async::Interrupt> for details on when and how |
46 | your perl program can be interrupted (and how to avoid it), and how to |
47 | your perl program can be interrupted (and how to avoid it), and how to |
47 | integrate background event loops into foreground ones. |
48 | integrate background event loops into foreground ones. |
48 | |
49 | |
49 | =head1 FAQ |
50 | =head1 FAQ |
|
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51 | |
|
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52 | =over 4 |
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53 | |
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54 | =item Why on earth...??? |
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55 | |
|
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56 | Sometimes you need lower latency for specific events, but it's too heavy |
|
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57 | to continuously poll for events. And perl already does this for you |
|
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58 | anyways, so this module only uses this existing mechanism. |
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59 | |
|
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60 | =item When do I have to lock? |
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61 | |
|
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62 | When in doubt, lock. Do not start or stop a watcher, do not create a |
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63 | watcher (unless with the C<_ns> methods) and do not DESTROY an active |
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64 | watcher without locking either. |
|
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65 | |
|
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66 | Any other event loop modifications need to be done while locked as |
|
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67 | well. So when in doubt, lock (best using C<scope_lock>). |
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68 | |
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69 | =item Why explicit locking? |
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70 | |
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71 | Because I was too lazy to wrap everything and there are probably only a |
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72 | few people on this world using this module. |
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73 | |
|
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74 | =back |
50 | |
75 | |
51 | =head1 FUNCTIONS, METHODS AND VARIABLES OF THIS MODULE |
76 | =head1 FUNCTIONS, METHODS AND VARIABLES OF THIS MODULE |
52 | |
77 | |
53 | =over 4 |
78 | =over 4 |
54 | |
79 | |
… | |
… | |
108 | $EV::Loop::Async::INTERRUPT->scope_block; |
133 | $EV::Loop::Async::INTERRUPT->scope_block; |
109 | # no default loop callbacks will be executed here. |
134 | # no default loop callbacks will be executed here. |
110 | # the loop will not be locked, however. |
135 | # the loop will not be locked, however. |
111 | } |
136 | } |
112 | |
137 | |
|
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138 | Example: embed the default EV::Async::Loop loop into the default L<EV> |
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139 | loop (note that it could be any other event loop as well). |
|
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140 | |
|
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141 | my $async_w = EV::io |
|
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142 | $EV::Loop::Async::LOOP->interrupt->pipe_fileno, |
|
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143 | EV::READ, |
|
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144 | sub { }; |
|
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145 | |
113 | =item $loop = new EV::Loop::Async $flags, [Async-Interrupt-Arguments...] |
146 | =item $loop = new EV::Loop::Async $flags, [Async-Interrupt-Arguments...] |
114 | |
147 | |
115 | This constructor: |
148 | This constructor: |
116 | |
149 | |
117 | =over 4 |
150 | =over 4 |
… | |
… | |
125 | =item 4. runs C<< $loop->run >> in that thread. |
158 | =item 4. runs C<< $loop->run >> in that thread. |
126 | |
159 | |
127 | =back |
160 | =back |
128 | |
161 | |
129 | The resulting loop will be running and unlocked when it is returned. |
162 | The resulting loop will be running and unlocked when it is returned. |
|
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163 | |
|
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164 | Example: create a new loop, block it's interrupt object and embed |
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165 | it into the foreground L<AnyEvent> event loop. This basically runs the |
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166 | C<EV::Loop::Async> loop in a synchronous way inside another loop. |
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167 | |
|
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168 | my $loop = new EV::Loop::Async 0; |
|
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169 | my $async = $loop->interrupt; |
|
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170 | |
|
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171 | $async->block; |
|
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172 | |
|
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173 | my $async_w = AnyEvent->io ( |
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174 | fh => $async->pipe_fileno, |
|
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175 | poll => "r", |
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176 | cb => sub { |
|
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177 | # temporarily unblock to handle events |
|
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178 | $async->unblock; |
|
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179 | $async->block; |
|
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180 | }, |
|
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181 | ); |
130 | |
182 | |
131 | =cut |
183 | =cut |
132 | |
184 | |
133 | sub new { |
185 | sub new { |
134 | my ($class, $flags, @asy) = @_; |
186 | my ($class, $flags, @asy) = @_; |
… | |
… | |
139 | $self->_attach ($asy, $asy->signal_func); |
191 | $self->_attach ($asy, $asy->signal_func); |
140 | |
192 | |
141 | $self |
193 | $self |
142 | } |
194 | } |
143 | |
195 | |
144 | =item $loop->nudge |
196 | =item $loop->notify |
145 | |
197 | |
146 | Wake up the asynchronous loop. This is useful after registering a new |
198 | Wake up the asynchronous loop. This is useful after registering a new |
147 | watcher, to ensure that the background event loop integrates the new |
199 | watcher, to ensure that the background event loop integrates the new |
148 | watcher(s) (which only happens when it iterates, which you can force by |
200 | watcher(s) (which only happens when it iterates, which you can force by |
149 | calling this method). |
201 | calling this method). |
150 | |
202 | |
151 | Without calling this method, the event loop I<eventually> takes notice |
203 | Without calling this method, the event loop I<eventually> takes notice |
152 | of new watchers, bit when this happens is not wlel-defined (can be |
204 | of new watchers, bit when this happens is not well-defined (can be |
153 | instantaneous, or take a few hours). |
205 | instantaneous, or take a few hours). |
154 | |
206 | |
155 | No locking is required. |
207 | No locking is required. |
156 | |
208 | |
157 | Example: lock the loop, create a timer, nudge the loop so it takes notice |
209 | Example: lock the loop, create a timer, nudge the loop so it takes notice |
… | |
… | |
161 | my $flag; |
213 | my $flag; |
162 | |
214 | |
163 | { |
215 | { |
164 | $loop->scope_lock; |
216 | $loop->scope_lock; |
165 | $timer = $loop->timer (1, 0, sub { $flag = 1 }); |
217 | $timer = $loop->timer (1, 0, sub { $flag = 1 }); |
166 | $loop->nudge; |
218 | $loop->notify; |
167 | } |
219 | } |
168 | |
220 | |
169 | 1 until $flag; |
221 | 1 until $flag; |
170 | |
222 | |
171 | =item $loop->lock |
223 | =item $loop->lock |
… | |
… | |
192 | =item $loop->scope_lock |
244 | =item $loop->scope_lock |
193 | |
245 | |
194 | Calls C<lock> immediately, and C<unlock> automatically whent he current |
246 | Calls C<lock> immediately, and C<unlock> automatically whent he current |
195 | scope is left. |
247 | scope is left. |
196 | |
248 | |
|
|
249 | =item $loop->set_max_foreground_loops ($max_loops) |
|
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250 | |
|
|
251 | The background loop will immediately stop polling for new events after it |
|
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252 | has collected at least one new event, regardless of how long it then takes |
|
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253 | to actually handle them. |
|
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254 | |
|
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255 | When Perl finally handles the events, there could be many more ready |
|
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256 | file descriptors. To improve latency and performance, you can ask |
|
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257 | C<EV::Loop::Async> to loop an additional number of times in the foreground |
|
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258 | after invoking the callbacks, effectively doing the polling in the |
|
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259 | foreground. |
|
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260 | |
|
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261 | The default is C<0>, meaning that no foreground polling will be done. A |
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262 | value of C<1> means that, after handling the pending events, it will call |
|
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263 | C<< $loop->loop (EV::LOOP_NONBLOCK) >> and handle the resulting events, if |
|
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264 | any. A value of C<2> means that this will be iterated twice. |
|
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265 | |
|
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266 | When a foreground event poll does not yield any new events, then no |
|
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267 | further iterations will be made, so this is only a I<maximum> value of |
|
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268 | additional loop runs. |
|
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269 | |
|
|
270 | Take also note of the standard EV C<set_io_collect_interval> |
|
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271 | functionality, which can achieve a similar, but different, effect - YMMV. |
|
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272 | |
197 | =back |
273 | =back |
198 | |
274 | |
199 | =head1 SEE ALSO |
275 | =head1 SEE ALSO |
200 | |
276 | |
201 | L<EV>, L<Async::Interrupt>. |
277 | L<EV>, L<Async::Interrupt>. |