void pushGenericCommand(client *c, int where) {
int j, waiting = 0, pushed = 0;
robj *lobj = lookupKeyWrite(c->db,c->argv[1]);
if (lobj && lobj->type != OBJ_LIST) {
addReply(c,shared.wrongtypeerr);
return;
}
for (j = 2; j < c->argc; j++) {
c->argv[j] = tryObjectEncoding(c->argv[j]);
if (!lobj) {
lobj = createQuicklistObject();
quicklistSetOptions(lobj->ptr, server.list_max_ziplist_size,
server.list_compress_depth);
dbAdd(c->db,c->argv[1],lobj);
}
listTypePush(lobj,c->argv[j],where);
pushed++;
}
addReplyLongLong(c, waiting + (lobj ? listTypeLength(lobj) : 0));
if (pushed) {
char *event = (where == LIST_HEAD) ? "lpush" : "rpush";
signalModifiedKey(c->db,c->argv[1]);
notifyKeyspaceEvent(NOTIFY_LIST,event,c->argv[1],c->db->id);
}
server.dirty += pushed;
}
void rpoplpushHandlePush(client *c, robj *dstkey, robj *dstobj, robj *value) {
/* Create the list if the key does not exist */
if (!dstobj) {
dstobj = createQuicklistObject();
quicklistSetOptions(dstobj->ptr, server.list_max_ziplist_size,
server.list_compress_depth);
dbAdd(c->db,dstkey,dstobj);
}
signalModifiedKey(c->db,dstkey);
listTypePush(dstobj,value,LIST_HEAD);
notifyKeyspaceEvent(NOTIFY_LIST,"lpush",dstkey,c->db->id);
/* Always send the pushed value to the client. */
addReplyBulk(c,value);
}
//PUSH命令的底层实现，where保存push的位置
void pushGenericCommand(client *c, int where) {
int j, waiting = 0, pushed = 0;
robj *lobj = lookupKeyWrite(c->db,c->argv[1]); //以写操作读取key对象的value
//如果value对象不是列表类型则发送错误信息，返回
if (lobj && lobj->type != OBJ_LIST) {
addReply(c,shared.wrongtypeerr);
return;
}
//从第一个value开始遍历
for (j = 2; j < c->argc; j++) {
c->argv[j] = tryObjectEncoding(c->argv[j]); //将value对象优化编码
//如果没有找到key对象
if (!lobj) {
//创建一个quicklist类型的对象
lobj = createQuicklistObject();
//设置ziplist最大的长度和压缩程度，配置文件指定
quicklistSetOptions(lobj->ptr, server.list_max_ziplist_size,
server.list_compress_depth);
//将新的key对象和优化编码过的value对象进行组成键值对
dbAdd(c->db,c->argv[1],lobj);
}
//在where推入一个value对象
listTypePush(lobj,c->argv[j],where);
pushed++; //更新计数器
}
//发送当前列表中元素的个数
addReplyLongLong(c, waiting + (lobj ? listTypeLength(lobj) : 0));
//如果推入元素成功
if (pushed) {
char *event = (where == LIST_HEAD) ? "lpush" : "rpush";
//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"lpush"或"rpush"事件通知
notifyKeyspaceEvent(NOTIFY_LIST,event,c->argv[1],c->db->id);
}
server.dirty += pushed; //更新脏键
}
//将一个value推入到列表头部，被rpoplpushCommand调用
void rpoplpushHandlePush(client *c, robj *dstkey, robj *dstobj, robj *value) {
/* Create the list if the key does not exist */
//如果目标dstkey不存在
if (!dstobj) {
//创建一个quicklist对象
dstobj = createQuicklistObject();
//设置ziplist的最大长度和压缩程度
quicklistSetOptions(dstobj->ptr, server.list_max_ziplist_size,
server.list_compress_depth);
//将key添加到数据库中
dbAdd(c->db,dstkey,dstobj);
}
//当数据库的键被改动，则会调用该函数发送信号
signalModifiedKey(c->db,dstkey);
//将vlaue推入到列表的头部
listTypePush(dstobj,value,LIST_HEAD);
//发送"lpush"时间通知
notifyKeyspaceEvent(NOTIFY_LIST,"lpush",dstkey,c->db->id);
/* Always send the pushed value to the client. */
//将value值发送给client
addReplyBulk(c,value);
}
