C++ signalModifiedKey函数代码示例

void renameGenericCommand(redisClient *c, int nx) {
    robj *o;
    long long expire;

    /* To use the same key as src and dst is probably an error */
    if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {
        addReply(c,shared.sameobjecterr);
        return;
    }

    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL)
        return;

    incrRefCount(o);
    expire = getExpire(c->db,c->argv[1]);
    if (lookupKeyWrite(c->db,c->argv[2]) != NULL) {
        if (nx) {
            decrRefCount(o);
            addReply(c,shared.czero);
            return;
        }
        /* Overwrite: delete the old key before creating the new one with the same name. */
        dbDelete(c->db,c->argv[2]);
    }
    dbAdd(c->db,c->argv[2],o);
    if (expire != -1) setExpire(c->db,c->argv[2],expire);
    dbDelete(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[2]);
    server.dirty++;
    addReply(c,nx ? shared.cone : shared.ok);
}

void renameGenericCommand(redisClient *c, int nx) {
    robj *o;

    /* To use the same key as src and dst is probably an error */
    if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) {
        addReply(c,shared.sameobjecterr);
        return;
    }

    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL)
        return;

    incrRefCount(o);
    if (dbAdd(c->db,c->argv[2],o) == REDIS_ERR) {
        if (nx) {
            decrRefCount(o);
            addReply(c,shared.czero);
            return;
        }
        dbReplace(c->db,c->argv[2],o);
    }
    dbDelete(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[2]);
    server.dirty++;
    addReply(c,nx ? shared.cone : shared.ok);
}

void expireGenericCommand(redisClient *c, robj *key, robj *param, long offset) {
    dictEntry *de;
    long seconds;

    if (getLongFromObjectOrReply(c, param, &seconds, NULL) != REDIS_OK) return;

    seconds -= offset;

    de = dictFind(c->db->dict,key->ptr);
    if (de == NULL) {
        addReply(c,shared.czero);
        return;
    }
    if (seconds <= 0) {
        if (dbDelete(c->db,key)) server.dirty++;
        addReply(c, shared.cone);
        signalModifiedKey(c->db,key);
        return;
    } else {
        time_t when = time(NULL)+seconds;
        setExpire(c->db,key,when);
        addReply(c,shared.cone);
        signalModifiedKey(c->db,key);
        server.dirty++;
        return;
    }
}

//当key存在时则push，PUSHX，INSERT命令的底层实现
void pushxGenericCommand(client *c, robj *refval, robj *val, int where) {
    robj *subject;
    listTypeIterator *iter;
    listTypeEntry entry;
    int inserted = 0;

    //以写操作读取key对象的value
    //如果读取失败或读取的value对象不是列表类型则返回
    if ((subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
        checkType(c,subject,OBJ_LIST)) return;

    //寻找基准值refval
    if (refval != NULL) {
        /* Seek refval from head to tail */
        //创建一个列表的迭代器
        iter = listTypeInitIterator(subject,0,LIST_TAIL);
        //将指向当前的entry节点保存到列表类型的entry中，然后指向下一个entry节点
        while (listTypeNext(iter,&entry)) {
            //当前的entry节点的值与基准值refval是否相等
            if (listTypeEqual(&entry,refval)) {
                //如果相等，根据where插入val对象
                listTypeInsert(&entry,val,where);
                inserted = 1;   //设置插入的标识，跳出循环
                break;
            }
        }
        //事项迭代器
        listTypeReleaseIterator(iter);

        //如果插入成功，键值被修改，则发送信号并且发送"linsert"时间通知
        if (inserted) {
            signalModifiedKey(c->db,c->argv[1]);
            notifyKeyspaceEvent(NOTIFY_LIST,"linsert",
                                c->argv[1],c->db->id);
            server.dirty++; //更新脏键
        } else {
            /* Notify client of a failed insert */
            //如果没有插入，则发送插入失败的信息
            addReply(c,shared.cnegone);
            return;
        }

    //如果基准值为空
    } else {
        //根据where判断出事件名称
        char *event = (where == LIST_HEAD) ? "lpush" : "rpush";

        //将val对象推入到列表的头部或尾部
        listTypePush(subject,val,where);
        //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]);
        //发送事件通知
        notifyKeyspaceEvent(NOTIFY_LIST,event,c->argv[1],c->db->id);
        server.dirty++; //更新脏键
    }

    //将插入val后的列表的元素个数发送给client
    addReplyLongLong(c,listTypeLength(subject));
}

void smoveCommand(client *c) {
    robj *srcset, *dstset, *ele;
    srcset = lookupKeyWrite(c->db,c->argv[1]);
    dstset = lookupKeyWrite(c->db,c->argv[2]);
    ele = c->argv[3];

    /* If the source key does not exist return 0 */
    if (srcset == NULL) {
        addReply(c,shared.czero);
        return;
    }

    /* If the source key has the wrong type, or the destination key
     * is set and has the wrong type, return with an error. */
    if (checkType(c,srcset,OBJ_SET) ||
        (dstset && checkType(c,dstset,OBJ_SET))) return;

    /* If srcset and dstset are equal, SMOVE is a no-op */
    if (srcset == dstset) {
        addReply(c,setTypeIsMember(srcset,ele->ptr) ?
            shared.cone : shared.czero);
        return;
    }

    /* If the element cannot be removed from the src set, return 0. */
    if (!setTypeRemove(srcset,ele->ptr)) {
        addReply(c,shared.czero);
        return;
    }
    notifyKeyspaceEvent(NOTIFY_SET,"srem",c->argv[1],c->db->id);

    /* Remove the src set from the database when empty */
    if (setTypeSize(srcset) == 0) {
        dbDelete(c->db,c->argv[1]);
        notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
    }

    /* Create the destination set when it doesn't exist */
    if (!dstset) {
        dstset = setTypeCreate(ele->ptr);
        dbAdd(c->db,c->argv[2],dstset);
    }

    signalModifiedKey(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[2]);
    server.dirty++;

    /* An extra key has changed when ele was successfully added to dstset */
    if (setTypeAdd(dstset,ele->ptr)) {
        server.dirty++;
        notifyKeyspaceEvent(NOTIFY_SET,"sadd",c->argv[2],c->db->id);
    }
    addReply(c,shared.cone);
}

void pushxGenericCommand(redisClient *c, robj *refval, robj *val, int where) {
    robj *subject;
    listTypeIterator *iter;
    listTypeEntry entry;
    int inserted = 0;
    int slotnum = keyHashSlot(c->argv[1]->ptr, sdslen(c->argv[1]->ptr));

    if ((subject = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
        checkType(c,subject,REDIS_LIST)) return;

    if (refval != NULL) {
        /* We're not sure if this value can be inserted yet, but we cannot
         * convert the list inside the iterator. We don't want to loop over
         * the list twice (once to see if the value can be inserted and once
         * to do the actual insert), so we assume this value can be inserted
         * and convert the ziplist to a regular list if necessary. */
        listTypeTryConversion(subject,val);

        /* Seek refval from head to tail */
        iter = listTypeInitIterator(subject,0,REDIS_TAIL);
        while (listTypeNext(iter,&entry)) {
            if (listTypeEqual(&entry,refval)) {
                listTypeInsert(&entry,val,where);
                inserted = 1;
                break;
            }
        }
        listTypeReleaseIterator(iter);

        if (inserted) {
            /* Check if the length exceeds the ziplist length threshold. */
            if (subject->encoding == REDIS_ENCODING_ZIPLIST &&
                ziplistLen(subject->ptr) > server.list_max_ziplist_entries)
                    listTypeConvert(subject,REDIS_ENCODING_LINKEDLIST);
            signalModifiedKey(c->db,c->argv[1],slotnum);
            notifyKeyspaceEvent(REDIS_NOTIFY_LIST,"linsert",
                                c->argv[1],c->db->id);
            server.dirty++;
        } else {
            /* Notify client of a failed insert */
            addReply(c,shared.cnegone);
            return;
        }
    } else {
        char *event = (where == REDIS_HEAD) ? "lpush" : "rpush";

        listTypePush(subject,val,where);
        signalModifiedKey(c->db,c->argv[1],slotnum);
        notifyKeyspaceEvent(REDIS_NOTIFY_LIST,event,c->argv[1],c->db->id);
        server.dirty++;
    }

    addReplyLongLong(c,listTypeLength(subject));
}

void pushxGenericCommand(redisClient *c, robj *refval, robj *val, int where) {
    robj *subject;
    listTypeIterator *iter;
    listTypeEntry entry;
    int inserted = 0;

    if ((subject = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
        checkType(c,subject,REDIS_LIST)) return;

    if (refval != NULL) {
        /* Note: we expect refval to be string-encoded because it is *not* the
         * last argument of the multi-bulk LINSERT. */
        redisAssertWithInfo(c,refval,refval->encoding == REDIS_ENCODING_RAW);

        /* We're not sure if this value can be inserted yet, but we cannot
         * convert the list inside the iterator. We don't want to loop over
         * the list twice (once to see if the value can be inserted and once
         * to do the actual insert), so we assume this value can be inserted
         * and convert the ziplist to a regular list if necessary. */
        listTypeTryConversion(subject,val);

        /* Seek refval from head to tail */
        iter = listTypeInitIterator(subject,0,REDIS_TAIL);
        while (listTypeNext(iter,&entry)) {
            if (listTypeEqual(&entry,refval)) {
                listTypeInsert(&entry,val,where);
                inserted = 1;
                break;
            }
        }
        listTypeReleaseIterator(iter);

        if (inserted) {
            /* Check if the length exceeds the ziplist length threshold. */
            if (subject->encoding == REDIS_ENCODING_ZIPLIST &&
                ziplistLen(subject->ptr) > server.list_max_ziplist_entries)
                    listTypeConvert(subject,REDIS_ENCODING_LINKEDLIST);
            signalModifiedKey(c->db,c->argv[1]);
            server.dirty++;
        } else {
            /* Notify client of a failed insert */
            addReply(c,shared.cnegone);
            return;
        }
    } else {
        listTypePush(subject,val,where);
        signalModifiedKey(c->db,c->argv[1]);
        server.dirty++;
    }

    addReplyLongLong(c,listTypeLength(subject));
}

void smoveCommand(redisClient* c)
{
    robj* srcset, *dstset, *ele;
    srcset = lookupKeyWrite(c->db, c->argv[1]);
    dstset = lookupKeyWrite(c->db, c->argv[2]);
    ele = c->argv[3] = tryObjectEncoding(c->argv[3]);

    /* If the source key does not exist return 0 */
    if (srcset == NULL) {
        addReply(c, shared.czero);
        return;
    }

    /* If the source key has the wrong type, or the destination key
     * is set and has the wrong type, return with an error. */
    if (checkType(c, srcset, REDIS_SET) ||
        (dstset && checkType(c, dstset, REDIS_SET))) {
        return;
    }

    /* If srcset and dstset are equal, SMOVE is a no-op */
    if (srcset == dstset) {
        addReply(c, shared.cone);
        return;
    }

    /* If the element cannot be removed from the src set, return 0. */
    if (!setTypeRemove(srcset, ele)) {
        addReply(c, shared.czero);
        return;
    }

    /* Remove the src set from the database when empty */
    if (setTypeSize(srcset) == 0) {
        dbDelete(c->db, c->argv[1]);
    }
    signalModifiedKey(c->db, c->argv[1]);
    signalModifiedKey(c->db, c->argv[2]);
    server.dirty++;

    /* Create the destination set when it doesn't exist */
    if (!dstset) {
        dstset = setTypeCreate(ele);
        dbAdd(c->db, c->argv[2], dstset);
    }

    /* An extra key has changed when ele was successfully added to dstset */
    if (setTypeAdd(dstset, ele)) {
        server.dirty++;
    }
    addReply(c, shared.cone);
}

/*SMOVE source destination member*/
void smoveCommand(redisClient *c) {//将member元素从source集合移动到destination集合
    robj *srcset, *dstset, *ele;
    srcset = lookupKeyWrite(c->db,c->argv[1]);
    dstset = lookupKeyWrite(c->db,c->argv[2]);
    ele = c->argv[3] = tryObjectEncoding(c->argv[3]);

    /* If the source key does not exist return 0 */
    if (srcset == NULL) {
        addReply(c,shared.czero);
        return;
    }

    /* If the source key has the wrong type, or the destination key
     * is set and has the wrong type, return with an error. */
    if (checkType(c,srcset,REDIS_SET) ||
        (dstset && checkType(c,dstset,REDIS_SET))) return;

    /* If srcset and dstset are equal, SMOVE is a no-op */
    if (srcset == dstset) {
        addReply(c,shared.cone);
        return;
    }

    /* If the element cannot be removed from the src set, return 0. */
    if (!setTypeRemove(srcset,ele)) {//从源集合中删除member元素
        addReply(c,shared.czero);
        return;
    }
    notifyKeyspaceEvent(REDIS_NOTIFY_SET,"srem",c->argv[1],c->db->id);

    /* Remove the src set from the database when empty */
    if (setTypeSize(srcset) == 0) {//移除member元素后，源集合为空，删除
        dbDelete(c->db,c->argv[1]);
        notifyKeyspaceEvent(REDIS_NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
    }
    signalModifiedKey(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[2]);
    server.dirty++;

    /* Create the destination set when it doesn't exist */
    if (!dstset) {//目标集合不存在，则新建
        dstset = setTypeCreate(ele);
        dbAdd(c->db,c->argv[2],dstset);
    }

    /* An extra key has changed when ele was successfully added to dstset */
    if (setTypeAdd(dstset,ele)) {//添加member元素到目标集合
        server.dirty++;
        notifyKeyspaceEvent(REDIS_NOTIFY_SET,"sadd",c->argv[2],c->db->id);
    }
    addReply(c,shared.cone);
}

//POP命令的底层实现，where保存pop的位置
void popGenericCommand(client *c, int where) {
    //以写操作取出key对象的value值
    robj *o = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk);
    // 如果key没找到或value对象不是列表类型则直接返回
    if (o == NULL || checkType(c,o,OBJ_LIST)) return;

    //从where 弹出一个value
    robj *value = listTypePop(o,where);
    //如果value为空，则发送空信息
    if (value == NULL) {
        addReply(c,shared.nullbulk);
    } else {
        //保存时间名称
        char *event = (where == LIST_HEAD) ? "lpop" : "rpop";

        //发送value给client
        addReplyBulk(c,value);
        //释放value对象
        decrRefCount(value);
        //发送事件通知
        notifyKeyspaceEvent(NOTIFY_LIST,event,c->argv[1],c->db->id);
        //如果弹出一个元素后，列表为空
        if (listTypeLength(o) == 0) {
            //发送"del"时间通知
            notifyKeyspaceEvent(NOTIFY_GENERIC,"del",
                                c->argv[1],c->db->id);
            //从数据库中删除当前的key
            dbDelete(c->db,c->argv[1]);
        }
        //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]);
        //更新脏键
        server.dirty++;
    }
}

void rpoplpushCommand(redisClient *c) {
    robj *sobj, *value;
    if ((sobj = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
        checkType(c,sobj,REDIS_LIST)) return;

    if (listTypeLength(sobj) == 0) {
        addReply(c,shared.nullbulk);
    } else {
        robj *dobj = lookupKeyWrite(c->db,c->argv[2]);
        robj *touchedkey = c->argv[1];

        if (dobj && checkType(c,dobj,REDIS_LIST)) return;
        value = listTypePop(sobj,REDIS_TAIL);
        /* We saved touched key, and protect it, since rpoplpushHandlePush
         * may change the client command argument vector. */
        incrRefCount(touchedkey);
        rpoplpushHandlePush(c,c,c->argv[2],dobj,value);

        /* listTypePop returns an object with its refcount incremented */
        decrRefCount(value);

        /* Delete the source list when it is empty */
        if (listTypeLength(sobj) == 0) dbDelete(c->db,touchedkey);
        signalModifiedKey(c->db,touchedkey);
        decrRefCount(touchedkey);
        server.dirty++;
    }
}

// t_hash.c
void hsetCommand(client *c) {
    robj *o;

    // create if not exist, default is ziplist
    if ((o = hashTypeLookupWriteOrCreate(c,c->argv[1])) == NULL) return;

    // if keylen or valuelen > hash_max_ziplist_value, then change to hashtable 
    // Notice: OBJ_ENCODING_HT never change back to OBJ_ENCODING_ZIPLIST
    hashTypeTryConversion(o,c->argv,2,3);
    hashTypeTryObjectEncoding(o,&c->argv[2], &c->argv[3]);

    update = hashTypeSet(o,c->argv[2],c->argv[3]);
        // if (o->encoding == OBJ_ENCODING_ZIPLIST) {
        //      ziplistDelete()
        //      ziplistInsert()
        //      
        //      if (hashTypeLength(o) > server.hash_max_ziplist_entries)
        //          hashTypeConvert(o, OBJ_ENCODING_HT);
        // }
        // else if (o->encoding == OBJ_ENCODING_HT) {
        //      dictReplace()
        // }

    // add to reply buffer 
    addReply(c, update ? shared.czero : shared.cone);

    signalModifiedKey(c->db,c->argv[1]);
    notifyKeyspaceEvent(NOTIFY_HASH,"hset",c->argv[1],c->db->id);
    server.dirty++;
}

void pushGenericCommand(redisClient *c, int where) {
    int j, addlen = 0, pushed = 0;
    robj *lobj = lookupKeyWrite(c->db,c->argv[1]);
    int may_have_waiting_clients = (lobj == NULL);

    if (lobj && lobj->type != REDIS_LIST) {
        addReply(c,shared.wrongtypeerr);
        return;
    }

    for (j = 2; j < c->argc; j++) {
        c->argv[j] = tryObjectEncoding(c->argv[j]);
        if (may_have_waiting_clients) {
            if (handleClientsWaitingListPush(c,c->argv[1],c->argv[j])) {
                addlen++;
                continue;
            } else {
                may_have_waiting_clients = 0;
            }
        }
        if (!lobj) {
            lobj = createZiplistObject();
            dbAdd(c->db,c->argv[1],lobj);
        }
        listTypePush(lobj,c->argv[j],where);
        pushed++;
    }
    addReplyLongLong(c,addlen + (lobj ? listTypeLength(lobj) : 0));
    if (pushed) signalModifiedKey(c->db,c->argv[1]);
    server.dirty += pushed;
}

void rpoplpushCommand(redisClient *c) {
    robj *sobj, *value;
    if ((sobj = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
        checkType(c,sobj,REDIS_LIST)) return;

    if (listTypeLength(sobj) == 0) {
        /* This may only happen after loading very old RDB files. Recent
         * versions of Redis delete keys of empty lists. */
        addReply(c,shared.nullbulk);
    } else {
        robj *dobj = lookupKeyWrite(c->db,c->argv[2]);
        robj *touchedkey = c->argv[1];

        if (dobj && checkType(c,dobj,REDIS_LIST)) return;
        value = listTypePop(sobj,REDIS_TAIL);
        /* We saved touched key, and protect it, since rpoplpushHandlePush
         * may change the client command argument vector (it does not
         * currently). */
        incrRefCount(touchedkey);
        rpoplpushHandlePush(c,c->argv[2],dobj,value);

        /* listTypePop returns an object with its refcount incremented */
        decrRefCount(value);

        /* Delete the source list when it is empty */
        if (listTypeLength(sobj) == 0) {
            dbDelete(c->db,touchedkey);
        }
        signalModifiedKey(c->db,touchedkey);
        decrRefCount(touchedkey);
    }
}

static void
slotsremove(redisClient *c, robj **keys, int n, int rewrite) {
    for (int i = 0; i < n; i ++) {
        dbDelete(c->db, keys[i]);
        signalModifiedKey(c->db, keys[i]);
        server.dirty ++;
    }
    if (!rewrite) {
        return;
    }
    for (int i = 0; i < n; i ++) {
        incrRefCount(keys[i]);
    }
    for (int i = 0; i < c->argc; i ++) {
        decrRefCount(c->argv[i]);
    }
    zfree(c->argv);
    c->argc = n + 1;
    c->argv = zmalloc(sizeof(robj *) * c->argc);
    c->argv[0] = createStringObject("DEL", 3);
    for (int i = 0; i < n; i ++) {
        c->argv[i + 1] = keys[i];
    }
    c->cmd = lookupCommandOrOriginal(c->argv[0]->ptr);
    redisAssertWithInfo(c, NULL, c->cmd != NULL);
}