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| 124 | =back |
124 | =back |
| 125 | |
125 | |
| 126 | For libev, you would typically use an C<ev_async> watcher: the |
126 | For libev, you would typically use an C<ev_async> watcher: the |
| 127 | C<want_poll> callback would invoke C<ev_async_send> to wake up the event |
127 | C<want_poll> callback would invoke C<ev_async_send> to wake up the event |
| 128 | loop. Inside the callback set for the watcher, one would call C<eio_poll |
128 | loop. Inside the callback set for the watcher, one would call C<eio_poll |
| 129 | ()> (followed by C<ev_async_send> again if C<eio_poll> indicates that not |
129 | ()>. |
| 130 | all requests have been handled yet). The race is taken care of because |
130 | |
| 131 | libev resets/rearms the async watcher before calling your callback, |
131 | If C<eio_poll ()> is configured to not handle all results in one go |
| 132 | and therefore, before calling C<eio_poll>. This might result in (some) |
132 | (i.e. it returns C<-1>) then you should start an idle watcher that calls |
| 133 | spurious wake-ups, but is generally harmless. |
133 | C<eio_poll> until it returns something C<!= -1>. |
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134 | |
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135 | A full-featured conenctor between libeio and libev would look as follows |
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136 | (if C<eio_poll> is handling all requests, it can of course be simplified a |
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137 | lot by removing the idle watcher logic): |
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138 | |
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139 | static struct ev_loop *loop; |
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140 | static ev_idle repeat_watcher; |
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141 | static ev_async ready_watcher; |
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142 | |
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143 | /* idle watcher callback, only used when eio_poll */ |
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144 | /* didn't handle all results in one call */ |
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145 | static void |
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146 | repeat (EV_P_ ev_idle *w, int revents) |
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147 | { |
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148 | if (eio_poll () != -1) |
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149 | ev_idle_stop (EV_A_ w); |
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150 | } |
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151 | |
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152 | /* eio has some results, process them */ |
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153 | static void |
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154 | ready (EV_P_ ev_async *w, int revents) |
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155 | { |
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156 | if (eio_poll () == -1) |
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157 | ev_idle_start (EV_A_ &repeat_watcher); |
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158 | } |
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159 | |
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160 | /* wake up the event loop */ |
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161 | static void |
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162 | want_poll (void) |
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163 | { |
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164 | ev_async_send (loop, &ready_watcher) |
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165 | } |
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166 | |
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167 | void |
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168 | my_init_eio () |
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169 | { |
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170 | loop = EV_DEFAULT; |
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171 | |
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172 | ev_idle_init (&repeat_watcher, repeat); |
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173 | ev_async_init (&ready_watcher, ready); |
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174 | ev_async_start (loop &watcher); |
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175 | |
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176 | eio_init (want_poll, 0); |
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177 | } |
| 134 | |
178 | |
| 135 | For most other event loops, you would typically use a pipe - the event |
179 | For most other event loops, you would typically use a pipe - the event |
| 136 | loop should be told to wait for read readiness on the read end. In |
180 | loop should be told to wait for read readiness on the read end. In |
| 137 | C<want_poll> you would write a single byte, in C<done_poll> you would try |
181 | C<want_poll> you would write a single byte, in C<done_poll> you would try |
| 138 | to read that byte, and in the callback for the read end, you would call |
182 | to read that byte, and in the callback for the read end, you would call |
| 139 | C<eio_poll>. The race is avoided here because the event loop should invoke |
183 | C<eio_poll>. |
| 140 | your callback again and again until the byte has been read (as the pipe |
184 | |
| 141 | read callback does not read it, only C<done_poll>). |
185 | You don't have to take special care in the case C<eio_poll> doesn't handle |
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186 | all requests, as the done callback will not be invoked, so the event loop |
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187 | will still signal readyness for the pipe until I<all> results have been |
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188 | processed. |
| 142 | |
189 | |
| 143 | |
190 | |
| 144 | =head1 HIGH LEVEL REQUEST API |
191 | =head1 HIGH LEVEL REQUEST API |
| 145 | |
192 | |
| 146 | Libeio has both a high-level API, which consists of calling a request |
193 | Libeio has both a high-level API, which consists of calling a request |
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| 323 | } |
370 | } |
| 324 | |
371 | |
| 325 | =item eio_realpath (const char *path, int pri, eio_cb cb, void *data) |
372 | =item eio_realpath (const char *path, int pri, eio_cb cb, void *data) |
| 326 | |
373 | |
| 327 | Similar to the realpath libc function, but unlike that one, result is |
374 | Similar to the realpath libc function, but unlike that one, result is |
| 328 | C<0> on failure and the length of the returned path in C<ptr2> - this is |
375 | C<-1> on failure and the length of the returned path in C<ptr2> (which is |
| 329 | similar to readlink. |
376 | not 0-terminated) - this is similar to readlink. |
| 330 | |
377 | |
| 331 | =item eio_stat (const char *path, int pri, eio_cb cb, void *data) |
378 | =item eio_stat (const char *path, int pri, eio_cb cb, void *data) |
| 332 | |
379 | |
| 333 | =item eio_lstat (const char *path, int pri, eio_cb cb, void *data) |
380 | =item eio_lstat (const char *path, int pri, eio_cb cb, void *data) |
| 334 | |
381 | |
