deps/hiredis/async.c

   1 /*
   2  * Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
   3  * Copyright (c) 2010, Pieter Noordhuis <pcnoordhuis at gmail dot com>
   4  *
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are met:
   9  *
  10  *   * Redistributions of source code must retain the above copyright notice,
  11  *     this list of conditions and the following disclaimer.
  12  *   * Redistributions in binary form must reproduce the above copyright
  13  *     notice, this list of conditions and the following disclaimer in the
  14  *     documentation and/or other materials provided with the distribution.
  15  *   * Neither the name of Redis nor the names of its contributors may be used
  16  *     to endorse or promote products derived from this software without
  17  *     specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  20  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  23  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <string.h>
  33 #include <assert.h>
  34 #include "async.h"
  35 #include "sds.h"
  36 #include "util.h"
  37
  38 /* Forward declaration of function in hiredis.c */
  39 void __redisAppendCommand(redisContext *c, char *cmd, size_t len);
  40
  41 static redisAsyncContext *redisAsyncInitialize(redisContext *c) {
  42     redisAsyncContext *ac = realloc(c,sizeof(redisAsyncContext));
  43     c = &(ac->c);
  44
  45     /* The regular connect functions will always set the flag REDIS_CONNECTED.
  46      * For the async API, we want to wait until the first write event is
  47      * received up before setting this flag, so reset it here. */
  48     c->flags &= ~REDIS_CONNECTED;
  49
  50     ac->err = 0;
  51     ac->errstr = NULL;
  52     ac->data = NULL;
  53     ac->_adapter_data = NULL;
  54
  55     ac->evAddRead = NULL;
  56     ac->evDelRead = NULL;
  57     ac->evAddWrite = NULL;
  58     ac->evDelWrite = NULL;
  59     ac->evCleanup = NULL;
  60
  61     ac->onConnect = NULL;
  62     ac->onDisconnect = NULL;
  63
  64     ac->replies.head = NULL;
  65     ac->replies.tail = NULL;
  66     return ac;
  67 }
  68
  69 /* We want the error field to be accessible directly instead of requiring
  70  * an indirection to the redisContext struct. */
  71 static void __redisAsyncCopyError(redisAsyncContext *ac) {
  72     redisContext *c = &(ac->c);
  73     ac->err = c->err;
  74     ac->errstr = c->errstr;
  75 }
  76
  77 redisAsyncContext *redisAsyncConnect(const char *ip, int port) {
  78     redisContext *c = redisConnectNonBlock(ip,port);
  79     redisAsyncContext *ac = redisAsyncInitialize(c);
  80     __redisAsyncCopyError(ac);
  81     return ac;
  82 }
  83
  84 redisAsyncContext *redisAsyncConnectUnix(const char *path) {
  85     redisContext *c = redisConnectUnixNonBlock(path);
  86     redisAsyncContext *ac = redisAsyncInitialize(c);
  87     __redisAsyncCopyError(ac);
  88     return ac;
  89 }
  90
  91 int redisAsyncSetReplyObjectFunctions(redisAsyncContext *ac, redisReplyObjectFunctions *fn) {
  92     redisContext *c = &(ac->c);
  93     return redisSetReplyObjectFunctions(c,fn);
  94 }
  95
  96 int redisAsyncSetConnectCallback(redisAsyncContext *ac, redisConnectCallback *fn) {
  97     if (ac->onConnect == NULL) {
  98         ac->onConnect = fn;
  99         return REDIS_OK;
 100     }
 101     return REDIS_ERR;
 102 }
 103
 104 int redisAsyncSetDisconnectCallback(redisAsyncContext *ac, redisDisconnectCallback *fn) {
 105     if (ac->onDisconnect == NULL) {
 106         ac->onDisconnect = fn;
 107         return REDIS_OK;
 108     }
 109     return REDIS_ERR;
 110 }
 111
 112 /* Helper functions to push/shift callbacks */
 113 static int __redisPushCallback(redisCallbackList *list, redisCallback *source) {
 114     redisCallback *cb;
 115
 116     /* Copy callback from stack to heap */
 117     cb = calloc(1,sizeof(*cb));
 118     if (!cb) redisOOM();
 119     if (source != NULL) {
 120         cb->fn = source->fn;
 121         cb->privdata = source->privdata;
 122     }
 123
 124     /* Store callback in list */
 125     if (list->head == NULL)
 126         list->head = cb;
 127     if (list->tail != NULL)
 128         list->tail->next = cb;
 129     list->tail = cb;
 130     return REDIS_OK;
 131 }
 132
 133 static int __redisShiftCallback(redisCallbackList *list, redisCallback *target) {
 134     redisCallback *cb = list->head;
 135     if (cb != NULL) {
 136         list->head = cb->next;
 137         if (cb == list->tail)
 138             list->tail = NULL;
 139
 140         /* Copy callback from heap to stack */
 141         if (target != NULL)
 142             memcpy(target,cb,sizeof(*cb));
 143         free(cb);
 144         return REDIS_OK;
 145     }
 146     return REDIS_ERR;
 147 }
 148
 149 /* Tries to do a clean disconnect from Redis, meaning it stops new commands
 150  * from being issued, but tries to flush the output buffer and execute
 151  * callbacks for all remaining replies.
 152  *
 153  * This functions is generally called from within a callback, so the
 154  * processCallbacks function will pick up the flag when there are no
 155  * more replies. */
 156 void redisAsyncDisconnect(redisAsyncContext *ac) {
 157     redisContext *c = &(ac->c);
 158     c->flags |= REDIS_DISCONNECTING;
 159 }
 160
 161 /* Helper function to make the disconnect happen and clean up. */
 162 static void __redisAsyncDisconnect(redisAsyncContext *ac) {
 163     redisContext *c = &(ac->c);
 164     redisCallback cb;
 165     int status;
 166
 167     /* Make sure error is accessible if there is any */
 168     __redisAsyncCopyError(ac);
 169     status = (ac->err == 0) ? REDIS_OK : REDIS_ERR;
 170
 171     if (status == REDIS_OK) {
 172         /* When the connection is cleanly disconnected, there should not
 173          * be pending callbacks. */
 174         assert(__redisShiftCallback(&ac->replies,NULL) == REDIS_ERR);
 175     } else {
 176         /* Callbacks should not be able to issue new commands. */
 177         c->flags |= REDIS_DISCONNECTING;
 178
 179         /* Execute pending callbacks with NULL reply. */
 180         while (__redisShiftCallback(&ac->replies,&cb) == REDIS_OK) {
 181             if (cb.fn != NULL)
 182                 cb.fn(ac,NULL,cb.privdata);
 183         }
 184     }
 185
 186     /* Signal event lib to clean up */
 187     if (ac->evCleanup) ac->evCleanup(ac->_adapter_data);
 188
 189     /* Execute callback with proper status */
 190     if (ac->onDisconnect) ac->onDisconnect(ac,status);
 191
 192     /* Cleanup self */
 193     redisFree(c);
 194 }
 195
 196 void redisProcessCallbacks(redisAsyncContext *ac) {
 197     redisContext *c = &(ac->c);
 198     redisCallback cb;
 199     void *reply = NULL;
 200     int status;
 201
 202     while((status = redisGetReply(c,&reply)) == REDIS_OK) {
 203         if (reply == NULL) {
 204             /* When the connection is being disconnected and there are
 205              * no more replies, this is the cue to really disconnect. */
 206             if (c->flags & REDIS_DISCONNECTING && sdslen(c->obuf) == 0) {
 207                 __redisAsyncDisconnect(ac);
 208                 return;
 209             }
 210
 211             /* When the connection is not being disconnected, simply stop
 212              * trying to get replies and wait for the next loop tick. */
 213             break;
 214         }
 215
 216         /* Shift callback and execute it */
 217         assert(__redisShiftCallback(&ac->replies,&cb) == REDIS_OK);
 218         if (cb.fn != NULL) {
 219             cb.fn(ac,reply,cb.privdata);
 220         } else {
 221             c->fn->freeObject(reply);
 222         }
 223     }
 224
 225     /* Disconnect when there was an error reading the reply */
 226     if (status != REDIS_OK)
 227         __redisAsyncDisconnect(ac);
 228 }
 229
 230 /* This function should be called when the socket is readable.
 231  * It processes all replies that can be read and executes their callbacks.
 232  */
 233 void redisAsyncHandleRead(redisAsyncContext *ac) {
 234     redisContext *c = &(ac->c);
 235
 236     if (redisBufferRead(c) == REDIS_ERR) {
 237         __redisAsyncDisconnect(ac);
 238     } else {
 239         /* Always re-schedule reads */
 240         if (ac->evAddRead) ac->evAddRead(ac->_adapter_data);
 241         redisProcessCallbacks(ac);
 242     }
 243 }
 244
 245 void redisAsyncHandleWrite(redisAsyncContext *ac) {
 246     redisContext *c = &(ac->c);
 247     int done = 0;
 248
 249     if (redisBufferWrite(c,&done) == REDIS_ERR) {
 250         __redisAsyncDisconnect(ac);
 251     } else {
 252         /* Continue writing when not done, stop writing otherwise */
 253         if (!done) {
 254             if (ac->evAddWrite) ac->evAddWrite(ac->_adapter_data);
 255         } else {
 256             if (ac->evDelWrite) ac->evDelWrite(ac->_adapter_data);
 257         }
 258
 259         /* Always schedule reads after writes */
 260         if (ac->evAddRead) ac->evAddRead(ac->_adapter_data);
 261
 262         /* Fire onConnect when this is the first write event. */
 263         if (!(c->flags & REDIS_CONNECTED)) {
 264             c->flags |= REDIS_CONNECTED;
 265             if (ac->onConnect) ac->onConnect(ac);
 266         }
 267     }
 268 }
 269
 270 /* Helper function for the redisAsyncCommand* family of functions.
 271  *
 272  * Write a formatted command to the output buffer and register the provided
 273  * callback function with the context.
 274  */
 275 static int __redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, char *cmd, size_t len) {
 276     redisContext *c = &(ac->c);
 277     redisCallback cb;
 278
 279     /* Don't accept new commands when the connection is lazily closed. */
 280     if (c->flags & REDIS_DISCONNECTING) return REDIS_ERR;
 281     __redisAppendCommand(c,cmd,len);
 282
 283     /* Store callback */
 284     cb.fn = fn;
 285     cb.privdata = privdata;
 286     __redisPushCallback(&ac->replies,&cb);
 287
 288     /* Always schedule a write when the write buffer is non-empty */
 289     if (ac->evAddWrite) ac->evAddWrite(ac->_adapter_data);
 290
 291     return REDIS_OK;
 292 }
 293
 294 int redisvAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, va_list ap) {
 295     char *cmd;
 296     int len;
 297     int status;
 298     len = redisvFormatCommand(&cmd,format,ap);
 299     status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
 300     free(cmd);
 301     return status;
 302 }
 303
 304 int redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, ...) {
 305     va_list ap;
 306     int status;
 307     va_start(ap,format);
 308     status = redisvAsyncCommand(ac,fn,privdata,format,ap);
 309     va_end(ap);
 310     return status;
 311 }
 312
 313 int redisAsyncCommandArgv(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, int argc, const char **argv, const size_t *argvlen) {
 314     char *cmd;
 315     int len;
 316     int status;
 317     len = redisFormatCommandArgv(&cmd,argc,argv,argvlen);
 318     status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
 319     free(cmd);
 320     return status;
 321 }