[[red – это изучение исходного кода 5] анализ восстановления команды redis

RESTORE key ttl serialized-value [REPLACE] [ABSTTL] [IDLETIME seconds] [FREQ frequency]

redis> DEL mykey
0
redis> RESTORE mykey 0 "\n\x17\x17\x00\x00\x00\x12\x00\x00\x00\x03\x00\
                        x00\xc0\x01\x00\x04\xc0\x02\x00\x04\xc0\x03\x00\
                        xff\x04\x00u#<\xc0;.\xe9\xdd"
OK
redis> TYPE mykey
list
redis> LRANGE mykey 0 -1
1) "1"
2) "2"
3) "3"

void restoreCommand(client *c) {
    long long ttl, lfu_freq = -1, lru_idle = -1, lru_clock = -1;
    rio payload;
    int j, type, replace = 0, absttl = 0;
    robj *obj;
    /*Analytic parameters*/
    for (j = 4; j < c->argc; j++) {
        int additional = c->argc-j-1;
        if (!strcasecmp(c->argv[j]->ptr,"replace")) {
            replace = 1;
        } else if (!strcasecmp(c->argv[j]->ptr,"absttl")) {
            absttl = 1;
        } else if (!strcasecmp(c->argv[j]->ptr,"idletime") && additional >= 1 &&
                   lfu_freq == -1)
        {
            if (getLongLongFromObjectOrReply(c,c->argv[j+1],&lru_idle,NULL)
                    != C_OK) return;
            if (lru_idle < 0) {
                addReplyError(c,"Invalid IDLETIME value, must be >= 0");
                return;
            }
            lru_clock = LRU_CLOCK();
            j++; /* Consume additional arg. */
        } else if (!strcasecmp(c->argv[j]->ptr,"freq") && additional >= 1 &&
                   lru_idle == -1)
        {
            if (getLongLongFromObjectOrReply(c,c->argv[j+1],&lfu_freq,NULL)
                    != C_OK) return;
            if (lfu_freq < 0 || lfu_freq > 255) {
                addReplyError(c,"Invalid FREQ value, must be >= 0 and <= 255");
                return;
            }
            j++; /* Consume additional arg. */
        } else {
            addReply(c,shared.syntaxerr);
            return;
        }
    }

/*This is to ensure whether the key exists. This operation is only performed when the replace is equal to 0*/
    if (!replace && lookupKeyWrite(c->db,c->argv[1]) != NULL) {
        addReply(c,shared.busykeyerr);
        return;
    }
        
    /*Check whether TTL is legal. The rule is whether it is less than 0 and whether it can be converted to a number*/
    if (getLongLongFromObjectOrReply(c,c->argv[2],&ttl,NULL) != C_OK) {
        return;
    } else if (ttl < 0) {
        addReplyError(c,"Invalid TTL value, must be >= 0");
        return;
    }
    //Check RDB version and data checksum. If they do not match, an error is returned.
    if (verifyDumpPayload(c->argv[3]->ptr,sdslen(c->argv[3]->ptr)) == C_ERR)
    {
        addReplyError(c,"DUMP payload version or checksum are wrong");
        return;
    }
    rioInitWithBuffer(&payload,c->argv[3]->ptr);
    if (((type = rdbLoadObjectType(&payload)) == -1) ||
        ((obj = rdbLoadObject(type,&payload)) == NULL))
    {
        addReplyError(c,"Bad data format");
        return;
    }
    //If it is replace mode, delete the key
    if (replace) dbDelete(c->db,c->argv[1]);

/* Create the key and set the TTL if any */
    Dbadd (C - > dB, C - > argv [1], obj); // if the key exists, an error is reported
    if (ttl) {
        if (!absttl) ttl+=mstime();
        setExpire(c,c->db,c->argv[1],ttl);
    }
    //Create a new key.
    //Set if TTL is present
    //If TTL is 0, there will be no expiration when the key is created, otherwise the specified expiration time (in milliseconds) will be set
    objectSetLRUOrLFU(obj,lfu_freq,lru_idle,lru_clock);
    //Set frequency and time range limits
    signalModifiedKey(c->db,c->argv[1]);
    addReply(c,shared.ok);
    server.dirty++;
}