/* Helper function to free the context. */
static void __redisAsyncFree(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
redisCallback cb;
dictIterator *it;
dictEntry *de;
// 执行所有等待队列中回调函数，将空回复传进去
/* Execute pending callbacks with NULL reply. */
while (__redisShiftCallback(&ac->replies,&cb) == REDIS_OK)
__redisRunCallback(ac,&cb,NULL);
// 执行所有等待队列中回调函数，将空回复传进去
// 这里是无效命令的回调函数
/* Execute callbacks for invalid commands */
while (__redisShiftCallback(&ac->sub.invalid,&cb) == REDIS_OK)
__redisRunCallback(ac,&cb,NULL);
// 执行所有等待队列中回调函数，将空回复传进去
// 这里是订阅发布的回调函数
/* Run subscription callbacks callbacks with NULL reply */
it = dictGetIterator(ac->sub.channels);
while ((de = dictNext(it)) != NULL)
__redisRunCallback(ac,dictGetEntryVal(de),NULL);
dictReleaseIterator(it);
dictRelease(ac->sub.channels);
// 执行所有等待队列中回调函数，将空回复传进去
// 这里是订阅发布的回调函数
it = dictGetIterator(ac->sub.patterns);
while ((de = dictNext(it)) != NULL)
__redisRunCallback(ac,dictGetEntryVal(de),NULL);
dictReleaseIterator(it);
dictRelease(ac->sub.patterns);
// 注销连接上的读写事件
/* Signal event lib to clean up */
_EL_CLEANUP(ac);
// 执行连接关闭回调函数，可做一些清理工作
/* 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);
}
}
// 释放 redisContext 中的内存
/* Cleanup self */
redisFree(c);
}
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); */
if (c->flags & REDIS_SUBSCRIBED) {
__redisGetSubscribeCallback(ac,reply,&cb);
}
/* lig: monitor callback */
if (c->flags & REDIS_MONITOR) {
__redisGetMonitorCallback(ac,&cb);
}
}
if (cb.fn != NULL) {
__redisRunCallback(ac,&cb,reply);
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);
}
void redisProcessCallbacks(redisAsyncContext *ac) {
redisContext *c = &(ac->c);
redisCallback cb;
void *reply = NULL;
int status;
while((status = redisGetReply(c,&reply)) == REDIS_OK) {
// 回复内容为空
if (reply == NULL) {
// REDIS_DISCONNECTING 表示连接断开的时候遇到了错误，如果此时
// 写缓冲区为空，会再次尝试断开。之后的回调函数都得不到执行
// 的机会
/* 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;
}
// 监视模式下
/* If monitor mode, repush callback */
if(c->flags & REDIS_MONITORING) {
__redisPushCallback(&ac->replies,&cb);
}
/* 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. */
// 获取回调函数 redisCallback
if (__redisShiftCallback(&ac->replies,&cb) != REDIS_OK) {
/*
* A spontaneous reply in a not-subscribed context can be the error
* reply that is sent when a new connection exceeds the maximum
* number of allowed connections on the server side.
*
* This is seen as an error instead of a regular reply because the
* server closes the connection after sending it.
*
* To prevent the error from being overwritten by an EOF error the
* connection is closed here. See issue #43.
*
* Another possibility is that the server is loading its dataset.
* In this case we also want to close the connection, and have the
* user wait until the server is ready to take our request.
*/
if (((redisReply*)reply)->type == REDIS_REPLY_ERROR) {
c->err = REDIS_ERR_OTHER;
snprintf(c->errstr,sizeof(c->errstr),"%s",((redisReply*)reply)->str);
__redisAsyncDisconnect(ac);
return;
}
/* No more regular callbacks and no errors, the context *must* be subscribed or monitoring. */
assert((c->flags & REDIS_SUBSCRIBED || c->flags & REDIS_MONITORING));
if(c->flags & REDIS_SUBSCRIBED)
__redisGetSubscribeCallback(ac,reply,&cb);
}
// 执行回调函数
if (cb.fn != NULL) {
__redisRunCallback(ac,&cb,reply);
c->reader->fn->freeObject(reply);
// 可能是之前遇到了不可修复的错误，被标记了 REDIS_FREEING。
// 倘若是在 callback 里面遇到的错误，redis 不能立即释放连接，
// 因为可能需要返回一些数据给客户端。因此 redis 选择在 callback
// 执行过后，才释放（关闭）连接。这个方法好酷。
/* Proceed with free'ing when redisAsyncFree() was called. */
if (c->flags & REDIS_FREEING) {
__redisAsyncFree(ac);
return;
}
// 没有设置回调函数，直接释放收到的数据
} 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->reader->fn->freeObject(reply);
}
}
// 出错了，则直接关闭
/* Disconnect when there was an error reading the reply */
if (status != REDIS_OK)
__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) {
/* A spontaneous reply in a not-subscribed context can only be the
* error reply that is sent when a new connection exceeds the
* maximum number of allowed connections on the server side. This
* is seen as an error instead of a regular reply because the
* server closes the connection after sending it. To prevent the
* error from being overwritten by an EOF error the connection is
* closed here. See issue #43. */
if ( !(c->flags & REDIS_SUBSCRIBED) && ((redisReply*)reply)->type == REDIS_REPLY_ERROR ) {
c->err = REDIS_ERR_OTHER;
snprintf(c->errstr,sizeof(c->errstr),"%s",((redisReply*)reply)->str);
__redisAsyncDisconnect(ac);
return;
}
/* No more regular callbacks and no errors, the context *must* be subscribed. */
assert(c->flags & REDIS_SUBSCRIBED);
__redisGetSubscribeCallback(ac,reply,&cb);
}
if (cb.fn != NULL) {
__redisRunCallback(ac,&cb,reply);
c->reader->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->reader->fn->freeObject(reply);
}
}
/* Disconnect when there was an error reading the reply */
if (status != REDIS_OK)
__redisAsyncDisconnect(ac);
}
