deps/hiredis/async.c

   1 /*
   2  * Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are met:
   7  *
   8  *   * Redistributions of source code must retain the above copyright notice,
   9  *     this list of conditions and the following disclaimer.
  10  *   * Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  *   * Neither the name of Redis nor the names of its contributors may be used
  14  *     to endorse or promote products derived from this software without
  15  *     specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27  * POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include <string.h>
  31 #include <assert.h>
  32 #include "async.h"
  33 #include "sds.h"
  34 #include "util.h"
  35
  36 /* Forward declaration of function in hiredis.c */
  37 void __redisAppendCommand(redisContext *c, char *cmd, size_t len);
  38
  39 static redisAsyncContext *redisAsyncInitialize(redisContext *c) {
  40     redisAsyncContext *ac = realloc(c,sizeof(redisAsyncContext));
  41     /* Set all bytes in the async part of the context to 0 */
  42     memset(ac+sizeof(redisContext),0,sizeof(redisAsyncContext)-sizeof(redisContext));
  43     return ac;
  44 }
  45
  46 /* We want the error field to be accessible directly instead of requiring
  47  * an indirection to the redisContext struct. */
  48 static void __redisAsyncCopyError(redisAsyncContext *ac) {
  49     redisContext *c = &(ac->c);
  50     ac->err = c->err;
  51     ac->errstr = c->errstr;
  52 }
  53
  54 redisAsyncContext *redisAsyncConnect(const char *ip, int port) {
  55     redisContext *c = redisConnectNonBlock(ip,port);
  56     redisAsyncContext *ac = redisAsyncInitialize(c);
  57     __redisAsyncCopyError(ac);
  58     return ac;
  59 }
  60
  61 redisAsyncContext *redisAsyncConnectUnix(const char *path) {
  62     redisContext *c = redisConnectUnixNonBlock(path);
  63     redisAsyncContext *ac = redisAsyncInitialize(c);
  64     __redisAsyncCopyError(ac);
  65     return ac;
  66 }
  67
  68 int redisAsyncSetReplyObjectFunctions(redisAsyncContext *ac, redisReplyObjectFunctions *fn) {
  69     redisContext *c = &(ac->c);
  70     return redisSetReplyObjectFunctions(c,fn);
  71 }
  72
  73 int redisAsyncSetDisconnectCallback(redisAsyncContext *ac, redisDisconnectCallback *fn) {
  74     if (ac->onDisconnect == NULL) {
  75         ac->onDisconnect = fn;
  76         return REDIS_OK;
  77     }
  78     return REDIS_ERR;
  79 }
  80
  81 /* Helper functions to push/shift callbacks */
  82 static int __redisPushCallback(redisCallbackList *list, redisCallback *source) {
  83     redisCallback *cb;
  84
  85     /* Copy callback from stack to heap */
  86     cb = calloc(1,sizeof(*cb));
  87     if (!cb) redisOOM();
  88     if (source != NULL) {
  89         cb->fn = source->fn;
  90         cb->privdata = source->privdata;
  91     }
  92
  93     /* Store callback in list */
  94     if (list->head == NULL)
  95         list->head = cb;
  96     if (list->tail != NULL)
  97         list->tail->next = cb;
  98     list->tail = cb;
  99     return REDIS_OK;
 100 }
 101
 102 static int __redisShiftCallback(redisCallbackList *list, redisCallback *target) {
 103     redisCallback *cb = list->head;
 104     if (cb != NULL) {
 105         list->head = cb->next;
 106         if (cb == list->tail)
 107             list->tail = NULL;
 108
 109         /* Copy callback from heap to stack */
 110         if (target != NULL)
 111             memcpy(target,cb,sizeof(*cb));
 112         free(cb);
 113         return REDIS_OK;
 114     }
 115     return REDIS_ERR;
 116 }
 117
 118 /* Tries to do a clean disconnect from Redis, meaning it stops new commands
 119  * from being issued, but tries to flush the output buffer and execute
 120  * callbacks for all remaining replies.
 121  *
 122  * This functions is generally called from within a callback, so the
 123  * processCallbacks function will pick up the flag when there are no
 124  * more replies. */
 125 void redisAsyncDisconnect(redisAsyncContext *ac) {
 126     redisContext *c = &(ac->c);
 127     c->flags |= REDIS_DISCONNECTING;
 128 }
 129
 130 /* Helper function to make the disconnect happen and clean up. */
 131 static void __redisAsyncDisconnect(redisAsyncContext *ac) {
 132     redisContext *c = &(ac->c);
 133     redisCallback cb;
 134     int status;
 135
 136     /* Make sure error is accessible if there is any */
 137     __redisAsyncCopyError(ac);
 138     status = (ac->err == 0) ? REDIS_OK : REDIS_ERR;
 139
 140     if (status == REDIS_OK) {
 141         /* When the connection is cleanly disconnected, there should not
 142          * be pending callbacks. */
 143         assert(__redisShiftCallback(&ac->replies,NULL) == REDIS_ERR);
 144     } else {
 145         /* Callbacks should not be able to issue new commands. */
 146         c->flags |= REDIS_DISCONNECTING;
 147
 148         /* Execute pending callbacks with NULL reply. */
 149         while (__redisShiftCallback(&ac->replies,&cb) == REDIS_OK) {
 150             if (cb.fn != NULL)
 151                 cb.fn(ac,NULL,cb.privdata);
 152         }
 153     }
 154
 155     /* Signal event lib to clean up */
 156     if (ac->evCleanup) ac->evCleanup(ac->data);
 157
 158     /* Execute callback with proper status */
 159     if (ac->onDisconnect) ac->onDisconnect(ac,status);
 160
 161     /* Cleanup self */
 162     redisFree(c);
 163 }
 164
 165 void redisProcessCallbacks(redisAsyncContext *ac) {
 166     redisContext *c = &(ac->c);
 167     redisCallback cb;
 168     void *reply = NULL;
 169     int status;
 170
 171     while((status = redisGetReply(c,&reply)) == REDIS_OK) {
 172         if (reply == NULL) {
 173             /* When the connection is being disconnected and there are
 174              * no more replies, this is the cue to really disconnect. */
 175             if (c->flags & REDIS_DISCONNECTING && sdslen(c->obuf) == 0) {
 176                 __redisAsyncDisconnect(ac);
 177                 return;
 178             }
 179
 180             /* When the connection is not being disconnected, simply stop
 181              * trying to get replies and wait for the next loop tick. */
 182             break;
 183         }
 184
 185         /* Shift callback and execute it */
 186         assert(__redisShiftCallback(&ac->replies,&cb) == REDIS_OK);
 187         if (cb.fn != NULL) {
 188             cb.fn(ac,reply,cb.privdata);
 189         } else {
 190             c->fn->freeObject(reply);
 191         }
 192     }
 193
 194     /* Disconnect when there was an error reading the reply */
 195     if (status != REDIS_OK)
 196         __redisAsyncDisconnect(ac);
 197 }
 198
 199 /* This function should be called when the socket is readable.
 200  * It processes all replies that can be read and executes their callbacks.
 201  */
 202 void redisAsyncHandleRead(redisAsyncContext *ac) {
 203     redisContext *c = &(ac->c);
 204
 205     if (redisBufferRead(c) == REDIS_ERR) {
 206         __redisAsyncDisconnect(ac);
 207     } else {
 208         /* Always re-schedule reads */
 209         if (ac->evAddRead) ac->evAddRead(ac->data);
 210         redisProcessCallbacks(ac);
 211     }
 212 }
 213
 214 void redisAsyncHandleWrite(redisAsyncContext *ac) {
 215     redisContext *c = &(ac->c);
 216     int done = 0;
 217
 218     if (redisBufferWrite(c,&done) == REDIS_ERR) {
 219         __redisAsyncDisconnect(ac);
 220     } else {
 221         /* Continue writing when not done, stop writing otherwise */
 222         if (!done) {
 223             if (ac->evAddWrite) ac->evAddWrite(ac->data);
 224         } else {
 225             if (ac->evDelWrite) ac->evDelWrite(ac->data);
 226         }
 227
 228         /* Always schedule reads when something was written */
 229         if (ac->evAddRead) ac->evAddRead(ac->data);
 230     }
 231 }
 232
 233 /* Helper function for the redisAsyncCommand* family of functions.
 234  *
 235  * Write a formatted command to the output buffer and register the provided
 236  * callback function with the context.
 237  */
 238 static int __redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, char *cmd, size_t len) {
 239     redisContext *c = &(ac->c);
 240     redisCallback cb;
 241
 242     /* Don't accept new commands when the connection is lazily closed. */
 243     if (c->flags & REDIS_DISCONNECTING) return REDIS_ERR;
 244     __redisAppendCommand(c,cmd,len);
 245
 246     /* Store callback */
 247     cb.fn = fn;
 248     cb.privdata = privdata;
 249     __redisPushCallback(&ac->replies,&cb);
 250
 251     /* Always schedule a write when the write buffer is non-empty */
 252     if (ac->evAddWrite) ac->evAddWrite(ac->data);
 253
 254     return REDIS_OK;
 255 }
 256
 257 int redisvAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, va_list ap) {
 258     char *cmd;
 259     int len;
 260     int status;
 261     len = redisvFormatCommand(&cmd,format,ap);
 262     status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
 263     free(cmd);
 264     return status;
 265 }
 266
 267 int redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, ...) {
 268     va_list ap;
 269     int status;
 270     va_start(ap,format);
 271     status = redisvAsyncCommand(ac,fn,privdata,format,ap);
 272     va_end(ap);
 273     return status;
 274 }
 275
 276 int redisAsyncCommandArgv(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, int argc, const char **argv, const size_t *argvlen) {
 277     char *cmd;
 278     int len;
 279     int status;
 280     len = redisFormatCommandArgv(&cmd,argc,argv,argvlen);
 281     status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
 282     free(cmd);
 283     return status;
 284 }