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comparison: ipc/chromium/src/third_party/libevent/bufferevent-internal.h
ipc/chromium/src/third_party/libevent/bufferevent-internal.h
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| 1 /* | |
| 2 * Copyright (c) 2008-2012 Niels Provos and Nick Mathewson | |
| 3 * | |
| 4 * Redistribution and use in source and binary forms, with or without | |
| 5 * modification, are permitted provided that the following conditions | |
| 6 * are met: | |
| 7 * 1. Redistributions of source code must retain the above copyright | |
| 8 * notice, this list of conditions and the following disclaimer. | |
| 9 * 2. Redistributions in binary form must reproduce the above copyright | |
| 10 * notice, this list of conditions and the following disclaimer in the | |
| 11 * documentation and/or other materials provided with the distribution. | |
| 12 * 3. The name of the author may not be used to endorse or promote products | |
| 13 * derived from this software without specific prior written permission. | |
| 14 * | |
| 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
| 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
| 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
| 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
| 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
| 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 25 */ | |
| 26 #ifndef _BUFFEREVENT_INTERNAL_H_ | |
| 27 #define _BUFFEREVENT_INTERNAL_H_ | |
| 28 | |
| 29 #ifdef __cplusplus | |
| 30 extern "C" { | |
| 31 #endif | |
| 32 | |
| 33 #include "event2/event-config.h" | |
| 34 #include "event2/util.h" | |
| 35 #include "defer-internal.h" | |
| 36 #include "evthread-internal.h" | |
| 37 #include "event2/thread.h" | |
| 38 #include "ratelim-internal.h" | |
| 39 #include "event2/bufferevent_struct.h" | |
| 40 | |
| 41 /* These flags are reasons that we might be declining to actually enable | |
| 42 reading or writing on a bufferevent. | |
| 43 */ | |
| 44 | |
| 45 /* On a all bufferevents, for reading: used when we have read up to the | |
| 46 watermark value. | |
| 47 | |
| 48 On a filtering bufferevent, for writing: used when the underlying | |
| 49 bufferevent's write buffer has been filled up to its watermark | |
| 50 value. | |
| 51 */ | |
| 52 #define BEV_SUSPEND_WM 0x01 | |
| 53 /* On a base bufferevent: when we have emptied a bandwidth buckets */ | |
| 54 #define BEV_SUSPEND_BW 0x02 | |
| 55 /* On a base bufferevent: when we have emptied the group's bandwidth bucket. */ | |
| 56 #define BEV_SUSPEND_BW_GROUP 0x04 | |
| 57 /* On a socket bufferevent: can't do any operations while we're waiting for | |
| 58 * name lookup to finish. */ | |
| 59 #define BEV_SUSPEND_LOOKUP 0x08 | |
| 60 /* On a base bufferevent, for reading: used when a filter has choked this | |
| 61 * (underlying) bufferevent because it has stopped reading from it. */ | |
| 62 #define BEV_SUSPEND_FILT_READ 0x10 | |
| 63 | |
| 64 typedef ev_uint16_t bufferevent_suspend_flags; | |
| 65 | |
| 66 struct bufferevent_rate_limit_group { | |
| 67 /** List of all members in the group */ | |
| 68 TAILQ_HEAD(rlim_group_member_list, bufferevent_private) members; | |
| 69 /** Current limits for the group. */ | |
| 70 struct ev_token_bucket rate_limit; | |
| 71 struct ev_token_bucket_cfg rate_limit_cfg; | |
| 72 | |
| 73 /** True iff we don't want to read from any member of the group.until | |
| 74 * the token bucket refills. */ | |
| 75 unsigned read_suspended : 1; | |
| 76 /** True iff we don't want to write from any member of the group.until | |
| 77 * the token bucket refills. */ | |
| 78 unsigned write_suspended : 1; | |
| 79 /** True iff we were unable to suspend one of the bufferevents in the | |
| 80 * group for reading the last time we tried, and we should try | |
| 81 * again. */ | |
| 82 unsigned pending_unsuspend_read : 1; | |
| 83 /** True iff we were unable to suspend one of the bufferevents in the | |
| 84 * group for writing the last time we tried, and we should try | |
| 85 * again. */ | |
| 86 unsigned pending_unsuspend_write : 1; | |
| 87 | |
| 88 /*@{*/ | |
| 89 /** Total number of bytes read or written in this group since last | |
| 90 * reset. */ | |
| 91 ev_uint64_t total_read; | |
| 92 ev_uint64_t total_written; | |
| 93 /*@}*/ | |
| 94 | |
| 95 /** The number of bufferevents in the group. */ | |
| 96 int n_members; | |
| 97 | |
| 98 /** The smallest number of bytes that any member of the group should | |
| 99 * be limited to read or write at a time. */ | |
| 100 ev_ssize_t min_share; | |
| 101 ev_ssize_t configured_min_share; | |
| 102 | |
| 103 /** Timeout event that goes off once a tick, when the bucket is ready | |
| 104 * to refill. */ | |
| 105 struct event master_refill_event; | |
| 106 /** Lock to protect the members of this group. This lock should nest | |
| 107 * within every bufferevent lock: if you are holding this lock, do | |
| 108 * not assume you can lock another bufferevent. */ | |
| 109 void *lock; | |
| 110 }; | |
| 111 | |
| 112 /** Fields for rate-limiting a single bufferevent. */ | |
| 113 struct bufferevent_rate_limit { | |
| 114 /* Linked-list elements for storing this bufferevent_private in a | |
| 115 * group. | |
| 116 * | |
| 117 * Note that this field is supposed to be protected by the group | |
| 118 * lock */ | |
| 119 TAILQ_ENTRY(bufferevent_private) next_in_group; | |
| 120 /** The rate-limiting group for this bufferevent, or NULL if it is | |
| 121 * only rate-limited on its own. */ | |
| 122 struct bufferevent_rate_limit_group *group; | |
| 123 | |
| 124 /* This bufferevent's current limits. */ | |
| 125 struct ev_token_bucket limit; | |
| 126 /* Pointer to the rate-limit configuration for this bufferevent. | |
| 127 * Can be shared. XXX reference-count this? */ | |
| 128 struct ev_token_bucket_cfg *cfg; | |
| 129 | |
| 130 /* Timeout event used when one this bufferevent's buckets are | |
| 131 * empty. */ | |
| 132 struct event refill_bucket_event; | |
| 133 }; | |
| 134 | |
| 135 /** Parts of the bufferevent structure that are shared among all bufferevent | |
| 136 * types, but not exposed in bufferevent_struct.h. */ | |
| 137 struct bufferevent_private { | |
| 138 /** The underlying bufferevent structure. */ | |
| 139 struct bufferevent bev; | |
| 140 | |
| 141 /** Evbuffer callback to enforce watermarks on input. */ | |
| 142 struct evbuffer_cb_entry *read_watermarks_cb; | |
| 143 | |
| 144 /** If set, we should free the lock when we free the bufferevent. */ | |
| 145 unsigned own_lock : 1; | |
| 146 | |
| 147 /** Flag: set if we have deferred callbacks and a read callback is | |
| 148 * pending. */ | |
| 149 unsigned readcb_pending : 1; | |
| 150 /** Flag: set if we have deferred callbacks and a write callback is | |
| 151 * pending. */ | |
| 152 unsigned writecb_pending : 1; | |
| 153 /** Flag: set if we are currently busy connecting. */ | |
| 154 unsigned connecting : 1; | |
| 155 /** Flag: set if a connect failed prematurely; this is a hack for | |
| 156 * getting around the bufferevent abstraction. */ | |
| 157 unsigned connection_refused : 1; | |
| 158 /** Set to the events pending if we have deferred callbacks and | |
| 159 * an events callback is pending. */ | |
| 160 short eventcb_pending; | |
| 161 | |
| 162 /** If set, read is suspended until one or more conditions are over. | |
| 163 * The actual value here is a bitfield of those conditions; see the | |
| 164 * BEV_SUSPEND_* flags above. */ | |
| 165 bufferevent_suspend_flags read_suspended; | |
| 166 | |
| 167 /** If set, writing is suspended until one or more conditions are over. | |
| 168 * The actual value here is a bitfield of those conditions; see the | |
| 169 * BEV_SUSPEND_* flags above. */ | |
| 170 bufferevent_suspend_flags write_suspended; | |
| 171 | |
| 172 /** Set to the current socket errno if we have deferred callbacks and | |
| 173 * an events callback is pending. */ | |
| 174 int errno_pending; | |
| 175 | |
| 176 /** The DNS error code for bufferevent_socket_connect_hostname */ | |
| 177 int dns_error; | |
| 178 | |
| 179 /** Used to implement deferred callbacks */ | |
| 180 struct deferred_cb deferred; | |
| 181 | |
| 182 /** The options this bufferevent was constructed with */ | |
| 183 enum bufferevent_options options; | |
| 184 | |
| 185 /** Current reference count for this bufferevent. */ | |
| 186 int refcnt; | |
| 187 | |
| 188 /** Lock for this bufferevent. Shared by the inbuf and the outbuf. | |
| 189 * If NULL, locking is disabled. */ | |
| 190 void *lock; | |
| 191 | |
| 192 /** Rate-limiting information for this bufferevent */ | |
| 193 struct bufferevent_rate_limit *rate_limiting; | |
| 194 }; | |
| 195 | |
| 196 /** Possible operations for a control callback. */ | |
| 197 enum bufferevent_ctrl_op { | |
| 198 BEV_CTRL_SET_FD, | |
| 199 BEV_CTRL_GET_FD, | |
| 200 BEV_CTRL_GET_UNDERLYING, | |
| 201 BEV_CTRL_CANCEL_ALL | |
| 202 }; | |
| 203 | |
| 204 /** Possible data types for a control callback */ | |
| 205 union bufferevent_ctrl_data { | |
| 206 void *ptr; | |
| 207 evutil_socket_t fd; | |
| 208 }; | |
| 209 | |
| 210 /** | |
| 211 Implementation table for a bufferevent: holds function pointers and other | |
| 212 information to make the various bufferevent types work. | |
| 213 */ | |
| 214 struct bufferevent_ops { | |
| 215 /** The name of the bufferevent's type. */ | |
| 216 const char *type; | |
| 217 /** At what offset into the implementation type will we find a | |
| 218 bufferevent structure? | |
| 219 | |
| 220 Example: if the type is implemented as | |
| 221 struct bufferevent_x { | |
| 222 int extra_data; | |
| 223 struct bufferevent bev; | |
| 224 } | |
| 225 then mem_offset should be offsetof(struct bufferevent_x, bev) | |
| 226 */ | |
| 227 off_t mem_offset; | |
| 228 | |
| 229 /** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does | |
| 230 not need to adjust the 'enabled' field. Returns 0 on success, -1 | |
| 231 on failure. | |
| 232 */ | |
| 233 int (*enable)(struct bufferevent *, short); | |
| 234 | |
| 235 /** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does | |
| 236 not need to adjust the 'enabled' field. Returns 0 on success, -1 | |
| 237 on failure. | |
| 238 */ | |
| 239 int (*disable)(struct bufferevent *, short); | |
| 240 | |
| 241 /** Free any storage and deallocate any extra data or structures used | |
| 242 in this implementation. | |
| 243 */ | |
| 244 void (*destruct)(struct bufferevent *); | |
| 245 | |
| 246 /** Called when the timeouts on the bufferevent have changed.*/ | |
| 247 int (*adj_timeouts)(struct bufferevent *); | |
| 248 | |
| 249 /** Called to flush data. */ | |
| 250 int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode); | |
| 251 | |
| 252 /** Called to access miscellaneous fields. */ | |
| 253 int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *); | |
| 254 | |
| 255 }; | |
| 256 | |
| 257 extern const struct bufferevent_ops bufferevent_ops_socket; | |
| 258 extern const struct bufferevent_ops bufferevent_ops_filter; | |
| 259 extern const struct bufferevent_ops bufferevent_ops_pair; | |
| 260 | |
| 261 #define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket) | |
| 262 #define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter) | |
| 263 #define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair) | |
| 264 | |
| 265 #ifdef WIN32 | |
| 266 extern const struct bufferevent_ops bufferevent_ops_async; | |
| 267 #define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async) | |
| 268 #else | |
| 269 #define BEV_IS_ASYNC(bevp) 0 | |
| 270 #endif | |
| 271 | |
| 272 /** Initialize the shared parts of a bufferevent. */ | |
| 273 int bufferevent_init_common(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options); | |
| 274 | |
| 275 /** For internal use: temporarily stop all reads on bufev, until the conditions | |
| 276 * in 'what' are over. */ | |
| 277 void bufferevent_suspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what); | |
| 278 /** For internal use: clear the conditions 'what' on bufev, and re-enable | |
| 279 * reading if there are no conditions left. */ | |
| 280 void bufferevent_unsuspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what); | |
| 281 | |
| 282 /** For internal use: temporarily stop all writes on bufev, until the conditions | |
| 283 * in 'what' are over. */ | |
| 284 void bufferevent_suspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what); | |
| 285 /** For internal use: clear the conditions 'what' on bufev, and re-enable | |
| 286 * writing if there are no conditions left. */ | |
| 287 void bufferevent_unsuspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what); | |
| 288 | |
| 289 #define bufferevent_wm_suspend_read(b) \ | |
| 290 bufferevent_suspend_read((b), BEV_SUSPEND_WM) | |
| 291 #define bufferevent_wm_unsuspend_read(b) \ | |
| 292 bufferevent_unsuspend_read((b), BEV_SUSPEND_WM) | |
| 293 | |
| 294 /* | |
| 295 Disable a bufferevent. Equivalent to bufferevent_disable(), but | |
| 296 first resets 'connecting' flag to force EV_WRITE down for sure. | |
| 297 | |
| 298 XXXX this method will go away in the future; try not to add new users. | |
| 299 See comment in evhttp_connection_reset() for discussion. | |
| 300 | |
| 301 @param bufev the bufferevent to be disabled | |
| 302 @param event any combination of EV_READ | EV_WRITE. | |
| 303 @return 0 if successful, or -1 if an error occurred | |
| 304 @see bufferevent_disable() | |
| 305 */ | |
| 306 int bufferevent_disable_hard(struct bufferevent *bufev, short event); | |
| 307 | |
| 308 /** Internal: Set up locking on a bufferevent. If lock is set, use it. | |
| 309 * Otherwise, use a new lock. */ | |
| 310 int bufferevent_enable_locking(struct bufferevent *bufev, void *lock); | |
| 311 /** Internal: Increment the reference count on bufev. */ | |
| 312 void bufferevent_incref(struct bufferevent *bufev); | |
| 313 /** Internal: Lock bufev and increase its reference count. | |
| 314 * unlocking it otherwise. */ | |
| 315 void _bufferevent_incref_and_lock(struct bufferevent *bufev); | |
| 316 /** Internal: Decrement the reference count on bufev. Returns 1 if it freed | |
| 317 * the bufferevent.*/ | |
| 318 int bufferevent_decref(struct bufferevent *bufev); | |
| 319 /** Internal: Drop the reference count on bufev, freeing as necessary, and | |
| 320 * unlocking it otherwise. Returns 1 if it freed the bufferevent. */ | |
| 321 int _bufferevent_decref_and_unlock(struct bufferevent *bufev); | |
| 322 | |
| 323 /** Internal: If callbacks are deferred and we have a read callback, schedule | |
| 324 * a readcb. Otherwise just run the readcb. */ | |
| 325 void _bufferevent_run_readcb(struct bufferevent *bufev); | |
| 326 /** Internal: If callbacks are deferred and we have a write callback, schedule | |
| 327 * a writecb. Otherwise just run the writecb. */ | |
| 328 void _bufferevent_run_writecb(struct bufferevent *bufev); | |
| 329 /** Internal: If callbacks are deferred and we have an eventcb, schedule | |
| 330 * it to run with events "what". Otherwise just run the eventcb. */ | |
| 331 void _bufferevent_run_eventcb(struct bufferevent *bufev, short what); | |
| 332 | |
| 333 /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in | |
| 334 * which case add ev with no timeout. */ | |
| 335 int _bufferevent_add_event(struct event *ev, const struct timeval *tv); | |
| 336 | |
| 337 /* ========= | |
| 338 * These next functions implement timeouts for bufferevents that aren't doing | |
| 339 * anything else with ev_read and ev_write, to handle timeouts. | |
| 340 * ========= */ | |
| 341 /** Internal use: Set up the ev_read and ev_write callbacks so that | |
| 342 * the other "generic_timeout" functions will work on it. Call this from | |
| 343 * the constructor function. */ | |
| 344 void _bufferevent_init_generic_timeout_cbs(struct bufferevent *bev); | |
| 345 /** Internal use: Delete the ev_read and ev_write callbacks if they're pending. | |
| 346 * Call this from the destructor function. */ | |
| 347 int _bufferevent_del_generic_timeout_cbs(struct bufferevent *bev); | |
| 348 /** Internal use: Add or delete the generic timeout events as appropriate. | |
| 349 * (If an event is enabled and a timeout is set, we add the event. Otherwise | |
| 350 * we delete it.) Call this from anything that changes the timeout values, | |
| 351 * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */ | |
| 352 int _bufferevent_generic_adj_timeouts(struct bufferevent *bev); | |
| 353 | |
| 354 /** Internal use: We have just successfully read data into an inbuf, so | |
| 355 * reset the read timeout (if any). */ | |
| 356 #define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \ | |
| 357 do { \ | |
| 358 if (evutil_timerisset(&(bev)->timeout_read)) \ | |
| 359 event_add(&(bev)->ev_read, &(bev)->timeout_read); \ | |
| 360 } while (0) | |
| 361 /** Internal use: We have just successfully written data from an inbuf, so | |
| 362 * reset the read timeout (if any). */ | |
| 363 #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \ | |
| 364 do { \ | |
| 365 if (evutil_timerisset(&(bev)->timeout_write)) \ | |
| 366 event_add(&(bev)->ev_write, &(bev)->timeout_write); \ | |
| 367 } while (0) | |
| 368 #define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \ | |
| 369 event_del(&(bev)->ev_read) | |
| 370 #define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \ | |
| 371 event_del(&(bev)->ev_write) | |
| 372 | |
| 373 | |
| 374 /** Internal: Given a bufferevent, return its corresponding | |
| 375 * bufferevent_private. */ | |
| 376 #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev) | |
| 377 | |
| 378 #ifdef _EVENT_DISABLE_THREAD_SUPPORT | |
| 379 #define BEV_LOCK(b) _EVUTIL_NIL_STMT | |
| 380 #define BEV_UNLOCK(b) _EVUTIL_NIL_STMT | |
| 381 #else | |
| 382 /** Internal: Grab the lock (if any) on a bufferevent */ | |
| 383 #define BEV_LOCK(b) do { \ | |
| 384 struct bufferevent_private *locking = BEV_UPCAST(b); \ | |
| 385 EVLOCK_LOCK(locking->lock, 0); \ | |
| 386 } while (0) | |
| 387 | |
| 388 /** Internal: Release the lock (if any) on a bufferevent */ | |
| 389 #define BEV_UNLOCK(b) do { \ | |
| 390 struct bufferevent_private *locking = BEV_UPCAST(b); \ | |
| 391 EVLOCK_UNLOCK(locking->lock, 0); \ | |
| 392 } while (0) | |
| 393 #endif | |
| 394 | |
| 395 | |
| 396 /* ==== For rate-limiting. */ | |
| 397 | |
| 398 int _bufferevent_decrement_write_buckets(struct bufferevent_private *bev, | |
| 399 ev_ssize_t bytes); | |
| 400 int _bufferevent_decrement_read_buckets(struct bufferevent_private *bev, | |
| 401 ev_ssize_t bytes); | |
| 402 ev_ssize_t _bufferevent_get_read_max(struct bufferevent_private *bev); | |
| 403 ev_ssize_t _bufferevent_get_write_max(struct bufferevent_private *bev); | |
| 404 | |
| 405 #ifdef __cplusplus | |
| 406 } | |
| 407 #endif | |
| 408 | |
| 409 | |
| 410 #endif /* _BUFFEREVENT_INTERNAL_H_ */ |
