void lremCommand(redisClient *c) {
robj *subject, *obj;
obj = c->argv[3] = tryObjectEncoding(c->argv[3]);
long toremove;
long removed = 0;
listTypeEntry entry;
int slotnum = keyHashSlot(c->argv[1]->ptr, sdslen(c->argv[1]->ptr));
if ((getLongFromObjectOrReply(c, c->argv[2], &toremove, NULL) != REDIS_OK))
return;
subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero,slotnum);
if (subject == NULL || checkType(c,subject,REDIS_LIST)) return;
/* Make sure obj is raw when we're dealing with a ziplist */
if (subject->encoding == REDIS_ENCODING_ZIPLIST)
obj = getDecodedObject(obj);
listTypeIterator *li;
if (toremove < 0) {
toremove = -toremove;
li = listTypeInitIterator(subject,-1,REDIS_HEAD);
} else {
li = listTypeInitIterator(subject,0,REDIS_TAIL);
}
while (listTypeNext(li,&entry)) {
if (listTypeEqual(&entry,obj)) {
listTypeDelete(&entry);
server.dirty++;
removed++;
if (toremove && removed == toremove) break;
}
}
listTypeReleaseIterator(li);
/* Clean up raw encoded object */
if (subject->encoding == REDIS_ENCODING_ZIPLIST)
decrRefCount(obj);
if (listTypeLength(subject) == 0) dbDelete(c->db,c->argv[1],slotnum);
addReplyLongLong(c,removed);
if (removed) signalModifiedKey(c->db,c->argv[1],slotnum);
}
void lremCommand(client *c) {
robj *subject, *obj;
obj = c->argv[3];
long toremove;
long removed = 0;
if ((getLongFromObjectOrReply(c, c->argv[2], &toremove, NULL) != C_OK))
return;
subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero);
if (subject == NULL || checkType(c,subject,OBJ_LIST)) return;
listTypeIterator *li;
if (toremove < 0) {
toremove = -toremove;
li = listTypeInitIterator(subject,-1,LIST_HEAD);
} else {
li = listTypeInitIterator(subject,0,LIST_TAIL);
}
listTypeEntry entry;
while (listTypeNext(li,&entry)) {
if (listTypeEqual(&entry,obj)) {
listTypeDelete(li, &entry);
server.dirty++;
removed++;
if (toremove && removed == toremove) break;
}
}
listTypeReleaseIterator(li);
if (removed) {
signalModifiedKey(c->db,c->argv[1]);
notifyKeyspaceEvent(NOTIFY_GENERIC,"lrem",c->argv[1],c->db->id);
}
if (listTypeLength(subject) == 0) {
dbDelete(c->db,c->argv[1]);
notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
}
addReplyLongLong(c,removed);
}
void lremCommand(redisClient *c) {
robj *subject, *obj = c->argv[3];
int toremove = atoi(c->argv[2]->ptr);
int removed = 0;
listTypeEntry entry;
subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero);
if (subject == NULL || checkType(c,subject,REDIS_LIST)) return;
/* Make sure obj is raw when we're dealing with a ziplist */
if (subject->encoding == REDIS_ENCODING_ZIPLIST)
obj = getDecodedObject(obj);
listTypeIterator *li;
if (toremove < 0) {
toremove = -toremove;
li = listTypeInitIterator(subject,-1,REDIS_HEAD);
} else {
li = listTypeInitIterator(subject,0,REDIS_TAIL);
}
while (listTypeNext(li,&entry)) {
if (listTypeEqual(&entry,obj)) {
listTypeDelete(&entry);
server.dirty++;
removed++;
if (toremove && removed == toremove) break;
}
}
listTypeReleaseIterator(li);
/* Clean up raw encoded object */
if (subject->encoding == REDIS_ENCODING_ZIPLIST)
decrRefCount(obj);
if (listTypeLength(subject) == 0) dbDelete(c->db,c->argv[1]);
addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",removed));
if (removed) touchWatchedKey(c->db,c->argv[1]);
}
// LREM key count value
// LREM命令
void lremCommand(client *c) {
robj *subject, *obj;
obj = c->argv[3];
long toremove;
long removed = 0;
//将字符串类型的count参数转换为long类型的整数，保存在toremove中
if ((getLongFromObjectOrReply(c, c->argv[2], &toremove, NULL) != C_OK))
return;
//以写操作读取出key对象的value值
subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero);
//如果key不存在或value对象不是列表类型则直接返回
if (subject == NULL || checkType(c,subject,OBJ_LIST)) return;
listTypeIterator *li;
if (toremove < 0) {
//如果toremove小于零，则从尾部向头部删除
toremove = -toremove;
//创建迭代器，指向尾部元素
li = listTypeInitIterator(subject,-1,LIST_HEAD);
} else {
//如果toremove大于等于零，则从头部向尾部删除，创建迭代器
li = listTypeInitIterator(subject,0,LIST_TAIL);
}
listTypeEntry entry;
//遍历列表，保存迭代器当前指向的entry
while (listTypeNext(li,&entry)) {
//如果当前entry的值是obj
if (listTypeEqual(&entry,obj)) {
//删除当前的entry
listTypeDelete(li, &entry);
//更新脏键
server.dirty++;
//更新计数器
removed++;
//如果删除了count个，则跳出循环
if (toremove && removed == toremove) break;
}
}
//释放迭代器
listTypeReleaseIterator(li);
//如果删除成功
if (removed) {
//当数据库的键被改动，则会调用该函数发送信号
signalModifiedKey(c->db,c->argv[1]);
//发送"lrem"时间通知
notifyKeyspaceEvent(NOTIFY_GENERIC,"lrem",c->argv[1],c->db->id);
}
//如果将列表中的元素全部删除完了
if (listTypeLength(subject) == 0) {
//从数据库中删除键key
dbDelete(c->db,c->argv[1]);
//发送"del"时间通知
notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
}
//发送删除元素的个数给client
addReplyLongLong(c,removed);
}