/* 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 */
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);
}
void rpopCommand(redisClient *c) {
popGenericCommand(c,REDIS_TAIL);
}
void lpopCommand(redisClient *c) {
popGenericCommand(c,REDIS_HEAD);
}
// RPOP key
// RPOP命令的实现
void rpopCommand(client *c) {
popGenericCommand(c,LIST_TAIL);
}
// LPOP key
// LPOP命令的实现
void lpopCommand(client *c) {
popGenericCommand(c,LIST_HEAD);
}
