hiredis/async.c

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/*
* Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
2010-12-16 21:08:39 +00:00
* Copyright (c) 2010, Pieter Noordhuis <pcnoordhuis at gmail dot com>
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <string.h>
#include <assert.h>
#include "async.h"
#include "sds.h"
#include "util.h"
/* Forward declaration of function in hiredis.c */
void __redisAppendCommand(redisContext *c, char *cmd, size_t len);
static redisAsyncContext *redisAsyncInitialize(redisContext *c) {
redisAsyncContext *ac = realloc(c,sizeof(redisAsyncContext));
c = &(ac->c);
/* The regular connect functions will always set the flag REDIS_CONNECTED.
* For the async API, we want to wait until the first write event is
* received up before setting this flag, so reset it here. */
c->flags &= ~REDIS_CONNECTED;
ac->err = 0;
ac->errstr = NULL;
ac->data = NULL;
ac->ev.data = NULL;
ac->ev.addRead = NULL;
ac->ev.delRead = NULL;
ac->ev.addWrite = NULL;
ac->ev.delWrite = NULL;
ac->ev.cleanup = NULL;
ac->onConnect = NULL;
ac->onDisconnect = NULL;
ac->replies.head = NULL;
ac->replies.tail = NULL;
return ac;
}
/* We want the error field to be accessible directly instead of requiring
* an indirection to the redisContext struct. */
static void __redisAsyncCopyError(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
ac->err = c->err;
ac->errstr = c->errstr;
}
redisAsyncContext *redisAsyncConnect(const char *ip, int port) {
redisContext *c = redisConnectNonBlock(ip,port);
redisAsyncContext *ac = redisAsyncInitialize(c);
__redisAsyncCopyError(ac);
return ac;
}
redisAsyncContext *redisAsyncConnectUnix(const char *path) {
redisContext *c = redisConnectUnixNonBlock(path);
redisAsyncContext *ac = redisAsyncInitialize(c);
__redisAsyncCopyError(ac);
return ac;
}
int redisAsyncSetReplyObjectFunctions(redisAsyncContext *ac, redisReplyObjectFunctions *fn) {
redisContext *c = &(ac->c);
return redisSetReplyObjectFunctions(c,fn);
}
int redisAsyncSetConnectCallback(redisAsyncContext *ac, redisConnectCallback *fn) {
if (ac->onConnect == NULL) {
ac->onConnect = fn;
/* The common way to detect an established connection is to wait for
* the first write event to be fired. This assumes the related event
* library functions are already set. */
if (ac->ev.addWrite) ac->ev.addWrite(ac->ev.data);
return REDIS_OK;
}
return REDIS_ERR;
}
int redisAsyncSetDisconnectCallback(redisAsyncContext *ac, redisDisconnectCallback *fn) {
if (ac->onDisconnect == NULL) {
ac->onDisconnect = fn;
return REDIS_OK;
}
return REDIS_ERR;
}
/* Helper functions to push/shift callbacks */
static int __redisPushCallback(redisCallbackList *list, redisCallback *source) {
redisCallback *cb;
/* Copy callback from stack to heap */
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cb = malloc(sizeof(*cb));
if (!cb) redisOOM();
if (source != NULL) {
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memcpy(cb,source,sizeof(*cb));
cb->next = NULL;
}
/* Store callback in list */
if (list->head == NULL)
list->head = cb;
if (list->tail != NULL)
list->tail->next = cb;
list->tail = cb;
return REDIS_OK;
}
static int __redisShiftCallback(redisCallbackList *list, redisCallback *target) {
redisCallback *cb = list->head;
if (cb != NULL) {
list->head = cb->next;
if (cb == list->tail)
list->tail = NULL;
/* Copy callback from heap to stack */
if (target != NULL)
memcpy(target,cb,sizeof(*cb));
free(cb);
return REDIS_OK;
}
return REDIS_ERR;
}
/* Helper function to free the context. */
static void __redisAsyncFree(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
redisCallback cb;
/* Execute pending callbacks with NULL reply. */
while (__redisShiftCallback(&ac->replies,&cb) == REDIS_OK) {
if (cb.fn != NULL) {
c->flags |= REDIS_IN_CALLBACK;
cb.fn(ac,NULL,cb.privdata);
c->flags &= ~REDIS_IN_CALLBACK;
}
}
/* Signal event lib to clean up */
if (ac->ev.cleanup) ac->ev.cleanup(ac->ev.data);
/* Execute disconnect callback. When redisAsyncFree() initiated destroying
* this context, the status will always be REDIS_OK. */
if (ac->onDisconnect && (c->flags & REDIS_CONNECTED)) {
if (c->flags & REDIS_FREEING) {
ac->onDisconnect(ac,REDIS_OK);
} else {
ac->onDisconnect(ac,(ac->err == 0) ? REDIS_OK : REDIS_ERR);
}
}
/* Cleanup self */
redisFree(c);
}
/* Free the async context. When this function is called from a callback,
* control needs to be returned to redisProcessCallbacks() before actual
* free'ing. To do so, a flag is set on the context which is picked up by
* redisProcessCallbacks(). Otherwise, the context is immediately free'd. */
void redisAsyncFree(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
c->flags |= REDIS_FREEING;
if (!(c->flags & REDIS_IN_CALLBACK))
__redisAsyncFree(ac);
}
/* Helper function to make the disconnect happen and clean up. */
static void __redisAsyncDisconnect(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
/* Make sure error is accessible if there is any */
__redisAsyncCopyError(ac);
if (ac->err == 0) {
/* For clean disconnects, there should be no pending callbacks. */
assert(__redisShiftCallback(&ac->replies,NULL) == REDIS_ERR);
} else {
/* Disconnection is caused by an error, make sure that pending
* callbacks cannot call new commands. */
c->flags |= REDIS_DISCONNECTING;
}
/* For non-clean disconnects, __redisAsyncFree() will execute pending
* callbacks with a NULL-reply. */
__redisAsyncFree(ac);
}
/* Tries to do a clean disconnect from Redis, meaning it stops new commands
* from being issued, but tries to flush the output buffer and execute
* callbacks for all remaining replies. When this function is called from a
* callback, there might be more replies and we can safely defer disconnecting
* to redisProcessCallbacks(). Otherwise, we can only disconnect immediately
* when there are no pending callbacks. */
void redisAsyncDisconnect(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
c->flags |= REDIS_DISCONNECTING;
if (!(c->flags & REDIS_IN_CALLBACK) && ac->replies.head == NULL)
__redisAsyncDisconnect(ac);
}
void redisProcessCallbacks(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
redisCallback cb;
void *reply = NULL;
int status;
while((status = redisGetReply(c,&reply)) == REDIS_OK) {
if (reply == NULL) {
/* When the connection is being disconnected and there are
* no more replies, this is the cue to really disconnect. */
if (c->flags & REDIS_DISCONNECTING && sdslen(c->obuf) == 0) {
__redisAsyncDisconnect(ac);
return;
}
/* When the connection is not being disconnected, simply stop
* trying to get replies and wait for the next loop tick. */
break;
}
/* Even if the context is subscribed, pending regular callbacks will
* get a reply before pub/sub messages arrive. */
if (__redisShiftCallback(&ac->replies,&cb) != REDIS_OK) {
/* No more regular callbacks, the context *must* be subscribed. */
assert(c->flags & REDIS_SUBSCRIBED);
/* TODO: find the right callback for pub/sub message. */
}
if (cb.fn != NULL) {
c->flags |= REDIS_IN_CALLBACK;
cb.fn(ac,reply,cb.privdata);
c->flags &= ~REDIS_IN_CALLBACK;
c->fn->freeObject(reply);
/* Proceed with free'ing when redisAsyncFree() was called. */
if (c->flags & REDIS_FREEING) {
__redisAsyncFree(ac);
return;
}
} else {
/* No callback for this reply. This can either be a NULL callback,
* or there were no callbacks to begin with. Either way, don't
* abort with an error, but simply ignore it because the client
* doesn't know what the server will spit out over the wire. */
c->fn->freeObject(reply);
}
}
/* Disconnect when there was an error reading the reply */
if (status != REDIS_OK)
__redisAsyncDisconnect(ac);
}
/* This function should be called when the socket is readable.
* It processes all replies that can be read and executes their callbacks.
*/
void redisAsyncHandleRead(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
if (redisBufferRead(c) == REDIS_ERR) {
__redisAsyncDisconnect(ac);
} else {
/* Always re-schedule reads */
if (ac->ev.addRead) ac->ev.addRead(ac->ev.data);
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redisProcessCallbacks(ac);
}
}
void redisAsyncHandleWrite(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
int done = 0;
if (redisBufferWrite(c,&done) == REDIS_ERR) {
__redisAsyncDisconnect(ac);
} else {
/* Continue writing when not done, stop writing otherwise */
if (!done) {
if (ac->ev.addWrite) ac->ev.addWrite(ac->ev.data);
} else {
if (ac->ev.delWrite) ac->ev.delWrite(ac->ev.data);
}
/* Always schedule reads after writes */
if (ac->ev.addRead) ac->ev.addRead(ac->ev.data);
/* Fire onConnect when this is the first write event. */
if (!(c->flags & REDIS_CONNECTED)) {
c->flags |= REDIS_CONNECTED;
if (ac->onConnect) ac->onConnect(ac);
}
}
}
/* Helper function for the redisAsyncCommand* family of functions.
*
* Write a formatted command to the output buffer and register the provided
* callback function with the context.
*/
static int __redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, char *cmd, size_t len) {
redisContext *c = &(ac->c);
redisCallback cb;
/* Don't accept new commands when the connection is about to be closed. */
if (c->flags & (REDIS_DISCONNECTING | REDIS_FREEING)) return REDIS_ERR;
__redisAppendCommand(c,cmd,len);
/* Store callback */
cb.fn = fn;
cb.privdata = privdata;
__redisPushCallback(&ac->replies,&cb);
/* Always schedule a write when the write buffer is non-empty */
if (ac->ev.addWrite) ac->ev.addWrite(ac->ev.data);
return REDIS_OK;
}
int redisvAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, va_list ap) {
char *cmd;
int len;
int status;
len = redisvFormatCommand(&cmd,format,ap);
status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
free(cmd);
return status;
}
int redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, const char *format, ...) {
va_list ap;
int status;
va_start(ap,format);
status = redisvAsyncCommand(ac,fn,privdata,format,ap);
va_end(ap);
return status;
}
int redisAsyncCommandArgv(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, int argc, const char **argv, const size_t *argvlen) {
char *cmd;
int len;
int status;
len = redisFormatCommandArgv(&cmd,argc,argv,argvlen);
status = __redisAsyncCommand(ac,fn,privdata,cmd,len);
free(cmd);
return status;
}