Function rewriteStreamObject

app/redis-6.2.6/src/aof.c:1286–1418

Emit the commands needed to rebuild a stream object. * The function returns 0 on error, 1 on success. */

/* Emit the commands needed to rebuild a stream object.
 * The function returns 0 on error, 1 on success. */
int rewriteStreamObject(rio *r, robj *key, robj *o) {
    stream *s = o->ptr;
    streamIterator si;
    streamIteratorStart(&si,s,NULL,NULL,0);
    streamID id;
    int64_t numfields;

    if (s->length) {
        /* Reconstruct the stream data using XADD commands. */
        while(streamIteratorGetID(&si,&id,&numfields)) {
            /* Emit a two elements array for each item. The first is
             * the ID, the second is an array of field-value pairs. */

            /* Emit the XADD <key> <id> ...fields... command. */
            if (!rioWriteBulkCount(r,'*',3+numfields*2) || 
                !rioWriteBulkString(r,"XADD",4) ||
                !rioWriteBulkObject(r,key) ||
                !rioWriteBulkStreamID(r,&id)) 
            {
                streamIteratorStop(&si);
                return 0;
            }
            while(numfields--) {
                unsigned char *field, *value;
                int64_t field_len, value_len;
                streamIteratorGetField(&si,&field,&value,&field_len,&value_len);
                if (!rioWriteBulkString(r,(char*)field,field_len) ||
                    !rioWriteBulkString(r,(char*)value,value_len)) 
                {
                    streamIteratorStop(&si);
                    return 0;                  
                }
            }
        }
    } else {
        /* Use the XADD MAXLEN 0 trick to generate an empty stream if
         * the key we are serializing is an empty string, which is possible
         * for the Stream type. */
        id.ms = 0; id.seq = 1; 
        if (!rioWriteBulkCount(r,'*',7) ||
            !rioWriteBulkString(r,"XADD",4) ||
            !rioWriteBulkObject(r,key) ||
            !rioWriteBulkString(r,"MAXLEN",6) ||
            !rioWriteBulkString(r,"0",1) ||
            !rioWriteBulkStreamID(r,&id) ||
            !rioWriteBulkString(r,"x",1) ||
            !rioWriteBulkString(r,"y",1))
        {
            streamIteratorStop(&si);
            return 0;     
        }
    }

    /* Append XSETID after XADD, make sure lastid is correct,
     * in case of XDEL lastid. */
    if (!rioWriteBulkCount(r,'*',3) ||
        !rioWriteBulkString(r,"XSETID",6) ||
        !rioWriteBulkObject(r,key) ||