void brpoplpushCommand(redisClient *c) {
time_t timeout;
if (getTimeoutFromObjectOrReply(c,c->argv[3],&timeout) != REDIS_OK)
return;
robj *key = lookupKeyWrite(c->db, c->argv[1]);
if (key == NULL) {
if (c->flags & REDIS_MULTI) {
/* Blocking against an empty list in a multi state
* returns immediately. */
addReply(c, shared.nullbulk);
} else {
/* The list is empty and the client blocks. */
blockForKeys(c, c->argv + 1, 1, timeout, c->argv[2]);
}
} else {
if (key->type != REDIS_LIST) {
addReply(c, shared.wrongtypeerr);
} else {
/* The list exists and has elements, so
* the regular rpoplpushCommand is executed. */
redisAssertWithInfo(c,key,listTypeLength(key) > 0);
rpoplpushCommand(c);
}
}
}
/* Blocking RPOP/LPOP */
void blockingPopGenericCommand(redisClient *c, int where) {
robj *o;
time_t timeout;
int j;
if (getTimeoutFromObjectOrReply(c,c->argv[c->argc-1],&timeout) != REDIS_OK)
return;
for (j = 1; j < c->argc-1; j++) {
o = lookupKeyWrite(c->db,c->argv[j]);
if (o != NULL) {
if (o->type != REDIS_LIST) {
addReply(c,shared.wrongtypeerr);
return;
} else {
if (listTypeLength(o) != 0) {
/* If the list contains elements fall back to the usual
* non-blocking POP operation */
robj *argv[2], **orig_argv;
int orig_argc;
/* We need to alter the command arguments before to call
* popGenericCommand() as the command takes a single key. */
orig_argv = c->argv;
orig_argc = c->argc;
argv[1] = c->argv[j];
c->argv = argv;
c->argc = 2;
/* Also the return value is different, we need to output
* the multi bulk reply header and the key name. The
* "real" command will add the last element (the value)
* for us. If this souds like an hack to you it's just
* because it is... */
addReplyMultiBulkLen(c,2);
addReplyBulk(c,argv[1]);
popGenericCommand(c,where);
/* Fix the client structure with the original stuff */
c->argv = orig_argv;
c->argc = orig_argc;
return;
}
}
}
}
/* If we are inside a MULTI/EXEC and the list is empty the only thing
* we can do is treating it as a timeout (even with timeout 0). */
if (c->flags & REDIS_MULTI) {
addReply(c,shared.nullmultibulk);
return;
}
/* If the list is empty or the key does not exists we must block */
blockForKeys(c, c->argv + 1, c->argc - 2, timeout, NULL);
}
/* Blocking RPOP/LPOP */
void blockingPopGenericCommand(redisClient *c, int where) {
robj *o;
mstime_t timeout;
int j;
int slotnum;
if (getTimeoutFromObjectOrReply(c,c->argv[c->argc-1],&timeout,UNIT_SECONDS)
!= REDIS_OK) return;
for (j = 1; j < c->argc-1; j++) {
slotnum = keyHashSlot(c->argv[j]->ptr, sdslen(c->argv[j]->ptr));
o = lookupKeyWrite(c->db,c->argv[j],slotnum);
if (o != NULL) {
if (o->type != REDIS_LIST) {
addReply(c,shared.wrongtypeerr);
return;
} else {
if (listTypeLength(o) != 0) {
/* Non empty list, this is like a non normal [LR]POP. */
char *event = (where == REDIS_HEAD) ? "lpop" : "rpop";
robj *value = listTypePop(o,where);
redisAssert(value != NULL);
addReplyMultiBulkLen(c,2);
addReplyBulk(c,c->argv[j]);
addReplyBulk(c,value);
decrRefCount(value);
notifyKeyspaceEvent(REDIS_NOTIFY_LIST,event,
c->argv[j],c->db->id);
if (listTypeLength(o) == 0) {
dbDelete(c->db,c->argv[j],slotnum);
notifyKeyspaceEvent(REDIS_NOTIFY_GENERIC,"del",
c->argv[j],c->db->id);
}
signalModifiedKey(c->db,c->argv[j],slotnum);
server.dirty++;
/* Replicate it as an [LR]POP instead of B[LR]POP. */
rewriteClientCommandVector(c,2,
(where == REDIS_HEAD) ? shared.lpop : shared.rpop,
c->argv[j]);
return;
}
}
}
}
/* If we are inside a MULTI/EXEC and the list is empty the only thing
* we can do is treating it as a timeout (even with timeout 0). */
if (c->flags & REDIS_MULTI) {
addReply(c,shared.nullmultibulk);
return;
}
/* If the list is empty or the key does not exists we must block */
blockForKeys(c, c->argv + 1, c->argc - 2, timeout, NULL);
}
/* Blocking RPOP/LPOP */
static void blockingPopGenericCommand(redisClient *c, int where) {
robj *o;
time_t timeout;
int j;
for (j = 1; j < c->argc-1; j++) {
o = lookupKeyWrite(c->db,c->argv[j]);
if (o != NULL) {
if (o->type != REDIS_LIST) {
addReply(c,shared.wrongtypeerr);
return;
} else {
list *list = o->ptr;
if (listLength(list) != 0) {
/* If the list contains elements fall back to the usual
* non-blocking POP operation */
robj *argv[2], **orig_argv;
int orig_argc;
/* We need to alter the command arguments before to call
* popGenericCommand() as the command takes a single key. */
orig_argv = c->argv;
orig_argc = c->argc;
argv[1] = c->argv[j];
c->argv = argv;
c->argc = 2;
/* Also the return value is different, we need to output
* the multi bulk reply header and the key name. The
* "real" command will add the last element (the value)
* for us. If this souds like an hack to you it's just
* because it is... */
addReplySds(c,sdsnew("*2\r\n"));
addReplyBulk(c,argv[1]);
popGenericCommand(c,where);
/* Fix the client structure with the original stuff */
c->argv = orig_argv;
c->argc = orig_argc;
return;
}
}
}
}
/* If the list is empty or the key does not exists we must block */
timeout = strtol(c->argv[c->argc-1]->ptr,NULL,10);
if (timeout > 0) timeout += time(NULL);
blockForKeys(c,c->argv+1,c->argc-2,timeout);
}
// BRPOPLPUSH source destination timeout
// BRPOPLPUSH命令的实现
void brpoplpushCommand(client *c) {
mstime_t timeout;
//以秒为单位取出超时时间
if (getTimeoutFromObjectOrReply(c,c->argv[3],&timeout,UNIT_SECONDS)
!= C_OK) return;
//以写操作读取出 source的值
robj *key = lookupKeyWrite(c->db, c->argv[1]);
//如果键为空，阻塞
if (key == NULL) {
// 如果命令在一个事务中执行，则发送一个空回复以避免死等待
if (c->flags & CLIENT_MULTI) {
/* Blocking against an empty list in a multi state
* returns immediately. */
addReply(c, shared.nullbulk);
} else {
/* The list is empty and the client blocks. */
// 列表为空，则将client阻塞
blockForKeys(c, c->argv + 1, 1, timeout, c->argv[2]);
}
//如果键不为空，指向RPOPLPUSH
} else {
//判断取出的value对象是否为列表类型，不是的话发送类型错误信息
if (key->type != OBJ_LIST) {
addReply(c, shared.wrongtypeerr);
} else {
/* The list exists and has elements, so
* the regular rpoplpushCommand is executed. */
// value对象的列表存在且有元素，所以调用普通的rpoplpush命令
serverAssertWithInfo(c,key,listTypeLength(key) > 0);
rpoplpushCommand(c);
}
}
}
// BRPOP BLPOP 命令的底层实现
// BLPOP key [key ...] timeout
void blockingPopGenericCommand(client *c, int where) {
robj *o;
mstime_t timeout;
int j;
// 以秒为单位取出timeout值
if (getTimeoutFromObjectOrReply(c,c->argv[c->argc-1],&timeout,UNIT_SECONDS)
!= C_OK) return;
//遍历所有的key
for (j = 1; j < c->argc-1; j++) {
//以写操作取出当前key的值
o = lookupKeyWrite(c->db,c->argv[j]);
// value对象不为空
if (o != NULL) {
// 如果value对象的类型不是列表类型，发送类型错误信息
if (o->type != OBJ_LIST) {
addReply(c,shared.wrongtypeerr);
return;
} else {
// 列表长度不为0
if (listTypeLength(o) != 0) {
/* Non empty list, this is like a non normal [LR]POP. */
// 保存事件名称
char *event = (where == LIST_HEAD) ? "lpop" : "rpop";
// 保存弹出的value对象
robj *value = listTypePop(o,where);
serverAssert(value != NULL);
// 发送回复给client
addReplyMultiBulkLen(c,2);
addReplyBulk(c,c->argv[j]);
addReplyBulk(c,value);
// 释放value
decrRefCount(value);
// 发送事件通知
notifyKeyspaceEvent(NOTIFY_LIST,event,
c->argv[j],c->db->id);
//如果弹出元素后列表为空
if (listTypeLength(o) == 0) {
//从数据库中删除当前的key
dbDelete(c->db,c->argv[j]);
// 发送"del"的事件通知
notifyKeyspaceEvent(NOTIFY_GENERIC,"del",
c->argv[j],c->db->id);
}
//数据库的键被修改，发送信号
signalModifiedKey(c->db,c->argv[j]);
//更新脏键
server.dirty++;
/* Replicate it as an [LR]POP instead of B[LR]POP. */
// 传播一个[LR]POP 而不是B[LR]POP
rewriteClientCommandVector(c,2,
(where == LIST_HEAD) ? shared.lpop : shared.rpop,
c->argv[j]);
return;
}
}
}
}
/* If we are inside a MULTI/EXEC and the list is empty the only thing
* we can do is treating it as a timeout (even with timeout 0). */
// 如果命令在一个事务中执行，则发送一个空回复以避免死等待
if (c->flags & CLIENT_MULTI) {
addReply(c,shared.nullmultibulk);
return;
}
/* If the list is empty or the key does not exists we must block */
// 参数中的所有键都不存在，则阻塞这些键
blockForKeys(c, c->argv + 1, c->argc - 2, timeout, NULL);
}
