Exemple #1
0
void verify(unsigned char *zl, zlentry *e) {
    int i;
    int len = ziplistLen(zl);
    zlentry _e;

    for (i = 0; i < len; i++) {
        memset(&e[i], 0, sizeof(zlentry));
        e[i] = zipEntry(ziplistIndex(zl, i));

        memset(&_e, 0, sizeof(zlentry));
        _e = zipEntry(ziplistIndex(zl, -len+i));

        assert(memcmp(&e[i], &_e, sizeof(zlentry)) == 0);
    }
}
Exemple #2
0
void lindexCommand(redisClient *c) {
    robj *o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk);
    if (o == NULL || checkType(c,o,REDIS_LIST)) return;
    int index = atoi(c->argv[2]->ptr);
    robj *value = NULL;

    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *p;
        unsigned char *vstr;
        unsigned int vlen;
        long long vlong;
        p = ziplistIndex(o->ptr,index);
        if (ziplistGet(p,&vstr,&vlen,&vlong)) {
            if (vstr) {
                value = createStringObject((char*)vstr,vlen);
            } else {
                value = createStringObjectFromLongLong(vlong);
            }
            addReplyBulk(c,value);
            decrRefCount(value);
        } else {
            addReply(c,shared.nullbulk);
        }
    } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
        listNode *ln = listIndex(o->ptr,index);
        if (ln != NULL) {
            value = listNodeValue(ln);
            addReplyBulk(c,value);
        } else {
            addReply(c,shared.nullbulk);
        }
    } else {
        redisPanic("Unknown list encoding");
    }
}
Exemple #3
0
/* Get the value from a ziplist encoded hash, identified by field.
 * Returns -1 when the field cannot be found. */
int hashTypeGetFromZiplist(robj *o, robj *field,
                           unsigned char **vstr,
                           unsigned int *vlen,
                           long long *vll)
{
    unsigned char *zl, *fptr = NULL, *vptr = NULL;
    int ret;

    logicErrorExpr(o->encoding == REDIS_ENCODING_ZIPLIST, "Never happend");

    field = getDecodedObject(field);

    zl = o->ptr;
    fptr = ziplistIndex(zl, ZIPLIST_HEAD);
    if (fptr != NULL) {
        fptr = ziplistFind(fptr, field->ptr, sdslen(field->ptr), 1);
        if (fptr != NULL) {
            /* Grab pointer to the value (fptr points to the field) */
            vptr = ziplistNext(zl, fptr);
            logicErrorExpr(vptr != NULL, "Never happend");
        }
    }

    decrRefCount(field);

    if (vptr != NULL) {
        ret = ziplistGet(vptr, vstr, vlen, vll);
        logicErrorExpr(ret, "Never happend");
        return 0;
    }

    return -1;
}
Exemple #4
0
/* Move to the next entry in the hash. Return REDIS_OK when the next entry
 * could be found and REDIS_ERR when the iterator reaches the end. */
int hashTypeNext(hashTypeIterator *hi) {
    if (hi->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *zl;
        unsigned char *fptr, *vptr;

        zl = hi->subject->ptr;
        fptr = hi->fptr;
        vptr = hi->vptr;

        if (fptr == NULL) {
            /* Initialize cursor */
                logicErrorExpr(vptr == NULL, "Never happend");
            fptr = ziplistIndex(zl, 0);
        } else {
            /* Advance cursor */
                logicErrorExpr(vptr != NULL, "Never happend");
            fptr = ziplistNext(zl, vptr);
        }
        if (fptr == NULL) return REDIS_ERR;

        /* Grab pointer to the value (fptr points to the field) */
        vptr = ziplistNext(zl, fptr);
        logicErrorExpr(vptr != NULL, "Never happend");

        /* fptr, vptr now point to the first or next pair */
        hi->fptr = fptr;
        hi->vptr = vptr;
    } else if (hi->encoding == REDIS_ENCODING_HT) {
        if ((hi->de = dictNext(hi->di)) == NULL) return REDIS_ERR;
    } else {
        logicError("Unknown hash encoding");
    }
    return REDIS_OK;
}
Exemple #5
0
/* Initialize an iterator at the specified index. */
listTypeIterator *listTypeInitIterator(robj *subject, PORT_LONG index, unsigned char direction) {
    listTypeIterator *li = zmalloc(sizeof(listTypeIterator));
    li->subject = subject;
    li->encoding = subject->encoding;
    li->direction = direction;
    if (li->encoding == REDIS_ENCODING_ZIPLIST) {
        li->zi = ziplistIndex(subject->ptr,(int)index);                         WIN_PORT_FIX /* cast (int) */
    } else if (li->encoding == REDIS_ENCODING_LINKEDLIST) {
Exemple #6
0
void lrangeCommand(redisClient *c) {
    robj *o;
    long start, end, llen, rangelen;

    if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != REDIS_OK) ||
        (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != REDIS_OK)) return;

    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptymultibulk)) == NULL
         || checkType(c,o,REDIS_LIST)) return;
    llen = listTypeLength(o);

    /* convert negative indexes */
    if (start < 0) start = llen+start;
    if (end < 0) end = llen+end;
    if (start < 0) start = 0;

    /* Invariant: start >= 0, so this test will be true when end < 0.
     * The range is empty when start > end or start >= length. */
    if (start > end || start >= llen) {
        addReply(c,shared.emptymultibulk);
        return;
    }
    if (end >= llen) end = llen-1;
    rangelen = (end-start)+1;

    /* Return the result in form of a multi-bulk reply */
    addReplyMultiBulkLen(c,rangelen);
    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *p = ziplistIndex(o->ptr,start);
        unsigned char *vstr;
        unsigned int vlen;
        long long vlong;

        while(rangelen--) {
            ziplistGet(p,&vstr,&vlen,&vlong);
            if (vstr) {
                addReplyBulkCBuffer(c,vstr,vlen);
            } else {
                addReplyBulkLongLong(c,vlong);
            }
            p = ziplistNext(o->ptr,p);
        }
    } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
        listNode *ln;

        /* If we are nearest to the end of the list, reach the element
         * starting from tail and going backward, as it is faster. */
        if (start > llen/2) start -= llen;
        ln = listIndex(o->ptr,start);

        while(rangelen--) {
            addReplyBulk(c,ln->value);
            ln = ln->next;
        }
    } else {
        redisPanic("List encoding is not LINKEDLIST nor ZIPLIST!");
    }
}
Exemple #7
0
/* Emit the commands needed to rebuild a list object.
 * The function returns 0 on error, 1 on success. */
int rewriteListObject(rio *r, robj *key, robj *o) {
    long long count = 0, items = listTypeLength(o);

    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *zl = o->ptr;
        unsigned char *p = ziplistIndex(zl,0);
        unsigned char *vstr;
        unsigned int vlen;
        long long vlong;

        while(ziplistGet(p,&vstr,&vlen,&vlong)) {
            if (count == 0) {
                int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ?
                    REDIS_AOF_REWRITE_ITEMS_PER_CMD : items;

                if (rioWriteBulkCount(r,'*',2+cmd_items) == 0) return 0;
                if (rioWriteBulkString(r,"RPUSH",5) == 0) return 0;
                if (rioWriteBulkObject(r,key) == 0) return 0;
            }
            if (vstr) {
                if (rioWriteBulkString(r,(char*)vstr,vlen) == 0) return 0;
            } else {
                if (rioWriteBulkLongLong(r,vlong) == 0) return 0;
            }
            p = ziplistNext(zl,p);
            if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0;
            items--;
        }
    } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
        list *list = o->ptr;
        listNode *ln;
        listIter li;

        listRewind(list,&li);
        while((ln = listNext(&li))) {
            robj *eleobj = listNodeValue(ln);

            if (count == 0) {
                int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ?
                    REDIS_AOF_REWRITE_ITEMS_PER_CMD : items;

                if (rioWriteBulkCount(r,'*',2+cmd_items) == 0) return 0;
                if (rioWriteBulkString(r,"RPUSH",5) == 0) return 0;
                if (rioWriteBulkObject(r,key) == 0) return 0;
            }
            if (rioWriteBulkObject(r,eleobj) == 0) return 0;
            if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0;
            items--;
        }
    } else {
        redisPanic("Unknown list encoding");
    }
    return 1;
}
Exemple #8
0
/* Add an element, discard the old if the key already exists.
 * Return 0 on insert and 1 on update.
 * This function will take care of incrementing the reference count of the
 * retained fields and value objects. */
int hashTypeSet(robj *o, robj *field, robj *value) {
    int update = 0;

    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *zl, *fptr, *vptr;

        field = getDecodedObject(field);
        value = getDecodedObject(value);

        zl = o->ptr;
        fptr = ziplistIndex(zl, ZIPLIST_HEAD);
        if (fptr != NULL) {
            fptr = ziplistFind(fptr, field->ptr, sdslen(field->ptr), 1);
            if (fptr != NULL) {
                /* Grab pointer to the value (fptr points to the field) */
                vptr = ziplistNext(zl, fptr);
                logicErrorExpr(vptr != NULL, "Never happend");
                update = 1;

                /* Delete value */
                zl = ziplistDelete(zl, &vptr);

                /* Insert new value */
                zl = ziplistInsert(zl, vptr, value->ptr, sdslen(value->ptr));
            }
        }

        if (!update) {
            /* Push new field/value pair onto the tail of the ziplist */
            zl = ziplistPush(zl, field->ptr, sdslen(field->ptr), ZIPLIST_TAIL);
            zl = ziplistPush(zl, value->ptr, sdslen(value->ptr), ZIPLIST_TAIL);
        }
        o->ptr = zl;
        decrRefCount(field);
        decrRefCount(value);

        /* Check if the ziplist needs to be converted to a hash table */
        if (hashTypeLength(o) > server.hash_max_ziplist_entries)
            hashTypeConvert(o, REDIS_ENCODING_HT);
    } else if (o->encoding == REDIS_ENCODING_HT) {
        if (dictReplace(o->ptr, field, value)) { /* Insert */
            incrRefCount(field);
        } else { /* Update */
            update = 1;
        }
        incrRefCount(value);
    } else {
        logicError("Unknown hash encoding");
    }
    return update;
}
Exemple #9
0
/* Initialize an iterator at the specified index. */
listTypeIterator *listTypeInitIterator(robj *subject, long index, unsigned char direction) {
    listTypeIterator *li = zmalloc(sizeof(listTypeIterator));
    li->subject = subject;
    li->encoding = subject->encoding;
    li->direction = direction;
    if (li->encoding == REDIS_ENCODING_ZIPLIST) {
        li->zi = ziplistIndex(subject->ptr,index);
    } else if (li->encoding == REDIS_ENCODING_LINKEDLIST) {
        li->ln = listIndex(subject->ptr,index);
    } else {
        redisPanic("Unknown list encoding");
    }
    return li;
}
Exemple #10
0
void lsetCommand(redisClient *c) {
	int slotnum = keyHashSlot(c->argv[1]->ptr, sdslen(c->argv[1]->ptr));
    robj *o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr,slotnum);
    if (o == NULL || checkType(c,o,REDIS_LIST)) return;
    long index;
    robj *value = (c->argv[3] = tryObjectEncoding(c->argv[3]));

    if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != REDIS_OK))
        return;

    listTypeTryConversion(o,value);
    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *p, *zl = o->ptr;
        p = ziplistIndex(zl,index);
        if (p == NULL) {
            addReply(c,shared.outofrangeerr);
        } else {
            o->ptr = ziplistDelete(o->ptr,&p);
            value = getDecodedObject(value);
            o->ptr = ziplistInsert(o->ptr,p,value->ptr,sdslen(value->ptr));
            decrRefCount(value);
            addReply(c,shared.ok);
            signalModifiedKey(c->db,c->argv[1],slotnum);
            notifyKeyspaceEvent(REDIS_NOTIFY_LIST,"lset",c->argv[1],c->db->id);
            server.dirty++;
        }
    } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
        listNode *ln = listIndex(o->ptr,index);
        if (ln == NULL) {
            addReply(c,shared.outofrangeerr);
        } else {
            decrRefCount((robj*)listNodeValue(ln));
            listNodeValue(ln) = value;
            incrRefCount(value);
            addReply(c,shared.ok);
            signalModifiedKey(c->db,c->argv[1],slotnum);
            notifyKeyspaceEvent(REDIS_NOTIFY_LIST,"lset",c->argv[1],c->db->id);
            server.dirty++;
        }
    } else {
        redisPanic("Unknown list encoding");
    }
}
Exemple #11
0
/* Get the value from a ziplist encoded hash, identified by field.
 * Returns -1 when the field cannot be found. */
int hashTypeGetFromZiplist(robj *o, robj *field,
                           unsigned char **vstr,
                           unsigned int *vlen,
                           PORT_LONGLONG *vll)
{
    unsigned char *zl, *fptr = NULL, *vptr = NULL;
    int ret;

    redisAssert(o->encoding == REDIS_ENCODING_ZIPLIST);

    field = getDecodedObject(field);

    zl = o->ptr;
    fptr = ziplistIndex(zl, ZIPLIST_HEAD);
    if (fptr != NULL) {
        fptr = ziplistFind(fptr, field->ptr, (unsigned int)sdslen(field->ptr), 1); WIN_PORT_FIX /* cast (unsigned int) */
        if (fptr != NULL) {
            /* Grab pointer to the value (fptr points to the field) */
            vptr = ziplistNext(zl, fptr);
            redisAssert(vptr != NULL);
        }
    }
Exemple #12
0
void lsetCommand(redisClient *c) {
    robj *o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr);
    if (o == NULL || checkType(c,o,REDIS_LIST)) return;
    int index = atoi(c->argv[2]->ptr);
    robj *value = (c->argv[3] = tryObjectEncoding(c->argv[3]));

    listTypeTryConversion(o,value);
    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *p, *zl = o->ptr;
        p = ziplistIndex(zl,index);
        if (p == NULL) {
            addReply(c,shared.outofrangeerr);
        } else {
            o->ptr = ziplistDelete(o->ptr,&p);
            value = getDecodedObject(value);
            o->ptr = ziplistInsert(o->ptr,p,value->ptr,sdslen(value->ptr));
            decrRefCount(value);
            addReply(c,shared.ok);
            signalModifiedKey(c->db,c->argv[1]);
            server.dirty++;
        }
    } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
        listNode *ln = listIndex(o->ptr,index);
        if (ln == NULL) {
            addReply(c,shared.outofrangeerr);
        } else {
            decrRefCount((robj*)listNodeValue(ln));
            listNodeValue(ln) = value;
            incrRefCount(value);
            addReply(c,shared.ok);
            signalModifiedKey(c->db,c->argv[1]);
            server.dirty++;
        }
    } else {
        redisPanic("Unknown list encoding");
    }
}
Exemple #13
0
robj *listTypePop(robj *subject, int where) {
    robj *value = NULL;
    if (subject->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *p;
        unsigned char *vstr;
        unsigned int vlen;
        long long vlong;
        int pos = (where == REDIS_HEAD) ? 0 : -1;
        p = ziplistIndex(subject->ptr,pos);
        if (ziplistGet(p,&vstr,&vlen,&vlong)) {
            if (vstr) {
                value = createStringObject((char*)vstr,vlen);
            } else {
                value = createStringObjectFromLongLong(vlong);
            }
            /* We only need to delete an element when it exists */
            subject->ptr = ziplistDelete(subject->ptr,&p);
        }
    } else if (subject->encoding == REDIS_ENCODING_LINKEDLIST) {
        list *list = subject->ptr;
        listNode *ln;
        if (where == REDIS_HEAD) {
            ln = listFirst(list);
        } else {
            ln = listLast(list);
        }
        if (ln != NULL) {
            value = listNodeValue(ln);
            incrRefCount(value);
            listDelNode(list,ln);
        }
    } else {
        redisPanic("Unknown list encoding");
    }
    return value;
}
Exemple #14
0
static void *loadZsetZiplistObject(unsigned char* zl, unsigned int *rlen) {
    unsigned int i = 0, len;
    unsigned char *eptr, *sptr;
    unsigned char *vstr;
    unsigned int vlen;
    int buf_len;
    long long vlong;
    double score;
    char buf[128];
    sds ele;

    len = ziplistLen (zl);
    eptr = ziplistIndex(zl,0);
    sptr = ziplistNext(zl,eptr);
    if(rdb_version < 2) {
        *rlen = len * 2;
    } else {
        *rlen = len;
    }
    sds *results = zmalloc(*rlen * sizeof(sds));
    while (eptr != NULL) {
        score = zzlGetScore(sptr);
        ziplistGet(eptr,&vstr,&vlen,&vlong);
        if (vstr == NULL)
            ele = sdsfromlonglong(vlong);
        else
            ele = sdsnewlen((char*)vstr,vlen);
        results[i] = ele;
        buf_len = snprintf(buf, 128, "%f", score);
        results[i+1] = sdsnewlen(buf, buf_len);
        i += 2;
        zzlNext(zl,&eptr,&sptr);
    }

    return results;
}
Exemple #15
0
/* Delete an element from a hash.
 * Return 1 on deleted and 0 on not found. */
int hashTypeDelete(robj *o, robj *field) {
    int deleted = 0;

    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *zl, *fptr;

        field = getDecodedObject(field);

        zl = o->ptr;
        fptr = ziplistIndex(zl, ZIPLIST_HEAD);
        if (fptr != NULL) {
            fptr = ziplistFind(fptr, field->ptr, sdslen(field->ptr), 1);
            if (fptr != NULL) {
                zl = ziplistDelete(zl,&fptr);
                zl = ziplistDelete(zl,&fptr);
                o->ptr = zl;
                deleted = 1;
            }
        }

        decrRefCount(field);

    } else if (o->encoding == REDIS_ENCODING_HT) {
        if (dictDelete((dict*)o->ptr, field) == REDIS_OK) {
            deleted = 1;

            /* Always check if the dictionary needs a resize after a delete. */
            if (htNeedsResize(o->ptr)) dictResize(o->ptr);
        }

    } else {
        logicError("Unknown hash encoding");
    }

    return deleted;
}
Exemple #16
0
void pop(unsigned char *zl, int where) {
    unsigned char *p, *vstr;
    unsigned int vlen;
    long long vlong;

    p = ziplistIndex(zl,where == ZIPLIST_HEAD ? 0 : -1);
    if (ziplistGet(p,&vstr,&vlen,&vlong)) {
        if (where == ZIPLIST_HEAD)
            printf("Pop head: ");
        else
            printf("Pop tail: ");

        if (vstr)
            if (vlen && fwrite(vstr,vlen,1,stdout) == 0) perror("fwrite");
        else
            printf("%lld", vlong);

        printf("\n");
        ziplistDeleteRange(zl,-1,1);
    } else {
        printf("ERROR: Could not pop\n");
        exit(1);
    }
}
Exemple #17
0
/* Write a sequence of commands able to fully rebuild the dataset into
 * "filename". Used both by REWRITEAOF and BGREWRITEAOF. */
int rewriteAppendOnlyFile(char *filename) {
    dictIterator *di = NULL;
    dictEntry *de;
    FILE *fp;
    char tmpfile[256];
    int j;
    time_t now = time(NULL);

    /* Note that we have to use a different temp name here compared to the
     * one used by rewriteAppendOnlyFileBackground() function. */
    snprintf(tmpfile,256,"temp-rewriteaof-%d.aof", (int) getpid());
    fp = fopen(tmpfile,"w");
    if (!fp) {
        redisLog(REDIS_WARNING, "Failed rewriting the append only file: %s", strerror(errno));
        return REDIS_ERR;
    }
    for (j = 0; j < server.dbnum; j++) {
        char selectcmd[] = "*2\r\n$6\r\nSELECT\r\n";
        redisDb *db = server.db+j;
        dict *d = db->dict;
        if (dictSize(d) == 0) continue;
        di = dictGetSafeIterator(d);
        if (!di) {
            fclose(fp);
            return REDIS_ERR;
        }

        /* SELECT the new DB */
        if (fwrite(selectcmd,sizeof(selectcmd)-1,1,fp) == 0) goto werr;
        if (fwriteBulkLongLong(fp,j) == 0) goto werr;

        /* Iterate this DB writing every entry */
        while((de = dictNext(di)) != NULL) {
            sds keystr = dictGetEntryKey(de);
            robj key, *o;
            time_t expiretime;
            int swapped;

            keystr = dictGetEntryKey(de);
            o = dictGetEntryVal(de);
            initStaticStringObject(key,keystr);
            /* If the value for this key is swapped, load a preview in memory.
             * We use a "swapped" flag to remember if we need to free the
             * value object instead to just increment the ref count anyway
             * in order to avoid copy-on-write of pages if we are forked() */
            if (!server.vm_enabled || o->storage == REDIS_VM_MEMORY ||
                o->storage == REDIS_VM_SWAPPING) {
                swapped = 0;
            } else {
                o = vmPreviewObject(o);
                swapped = 1;
            }
            expiretime = getExpire(db,&key);

            /* Save the key and associated value */
            if (o->type == REDIS_STRING) {
                /* Emit a SET command */
                char cmd[]="*3\r\n$3\r\nSET\r\n";
                if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                /* Key and value */
                if (fwriteBulkObject(fp,&key) == 0) goto werr;
                if (fwriteBulkObject(fp,o) == 0) goto werr;
            } else if (o->type == REDIS_LIST) {
                /* Emit the RPUSHes needed to rebuild the list */
                char cmd[]="*3\r\n$5\r\nRPUSH\r\n";
                if (o->encoding == REDIS_ENCODING_ZIPLIST) {
                    unsigned char *zl = o->ptr;
                    unsigned char *p = ziplistIndex(zl,0);
                    unsigned char *vstr;
                    unsigned int vlen;
                    long long vlong;

                    while(ziplistGet(p,&vstr,&vlen,&vlong)) {
                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (vstr) {
                            if (fwriteBulkString(fp,(char*)vstr,vlen) == 0)
                                goto werr;
                        } else {
                            if (fwriteBulkLongLong(fp,vlong) == 0)
                                goto werr;
                        }
                        p = ziplistNext(zl,p);
                    }
                } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
                    list *list = o->ptr;
                    listNode *ln;
                    listIter li;

                    listRewind(list,&li);
                    while((ln = listNext(&li))) {
                        robj *eleobj = listNodeValue(ln);

                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (fwriteBulkObject(fp,eleobj) == 0) goto werr;
                    }
                } else {
                    redisPanic("Unknown list encoding");
                }
            } else if (o->type == REDIS_SET) {
                char cmd[]="*3\r\n$4\r\nSADD\r\n";

                /* Emit the SADDs needed to rebuild the set */
                if (o->encoding == REDIS_ENCODING_INTSET) {
                    int ii = 0;
                    int64_t llval;
                    while(intsetGet(o->ptr,ii++,&llval)) {
                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (fwriteBulkLongLong(fp,llval) == 0) goto werr;
                    }
                } else if (o->encoding == REDIS_ENCODING_HT) {
                    dictIterator *di = dictGetIterator(o->ptr);
                    dictEntry *de;
                    while((de = dictNext(di)) != NULL) {
                        robj *eleobj = dictGetEntryKey(de);
                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (fwriteBulkObject(fp,eleobj) == 0) goto werr;
                    }
                    dictReleaseIterator(di);
                } else {
                    redisPanic("Unknown set encoding");
                }
            } else if (o->type == REDIS_ZSET) {
                /* Emit the ZADDs needed to rebuild the sorted set */
                char cmd[]="*4\r\n$4\r\nZADD\r\n";

                if (o->encoding == REDIS_ENCODING_ZIPLIST) {
                    unsigned char *zl = o->ptr;
                    unsigned char *eptr, *sptr;
                    unsigned char *vstr;
                    unsigned int vlen;
                    long long vll;
                    double score;

                    eptr = ziplistIndex(zl,0);
                    redisAssert(eptr != NULL);
                    sptr = ziplistNext(zl,eptr);
                    redisAssert(sptr != NULL);

                    while (eptr != NULL) {
                        redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
                        score = zzlGetScore(sptr);

                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (fwriteBulkDouble(fp,score) == 0) goto werr;
                        if (vstr != NULL) {
                            if (fwriteBulkString(fp,(char*)vstr,vlen) == 0)
                                goto werr;
                        } else {
                            if (fwriteBulkLongLong(fp,vll) == 0)
                                goto werr;
                        }
                        zzlNext(zl,&eptr,&sptr);
                    }
                } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
                    zset *zs = o->ptr;
                    dictIterator *di = dictGetIterator(zs->dict);
                    dictEntry *de;

                    while((de = dictNext(di)) != NULL) {
                        robj *eleobj = dictGetEntryKey(de);
                        double *score = dictGetEntryVal(de);

                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (fwriteBulkDouble(fp,*score) == 0) goto werr;
                        if (fwriteBulkObject(fp,eleobj) == 0) goto werr;
                    }
                    dictReleaseIterator(di);
                } else {
                    redisPanic("Unknown sorted set encoding");
                }
            } else if (o->type == REDIS_HASH) {
                char cmd[]="*4\r\n$4\r\nHSET\r\n";

                /* Emit the HSETs needed to rebuild the hash */
                if (o->encoding == REDIS_ENCODING_ZIPMAP) {
                    unsigned char *p = zipmapRewind(o->ptr);
                    unsigned char *field, *val;
                    unsigned int flen, vlen;

                    while((p = zipmapNext(p,&field,&flen,&val,&vlen)) != NULL) {
                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (fwriteBulkString(fp,(char*)field,flen) == 0)
                            goto werr;
                        if (fwriteBulkString(fp,(char*)val,vlen) == 0)
                            goto werr;
                    }
                } else {
                    dictIterator *di = dictGetIterator(o->ptr);
                    dictEntry *de;

                    while((de = dictNext(di)) != NULL) {
                        robj *field = dictGetEntryKey(de);
                        robj *val = dictGetEntryVal(de);

                        if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                        if (fwriteBulkObject(fp,&key) == 0) goto werr;
                        if (fwriteBulkObject(fp,field) == 0) goto werr;
                        if (fwriteBulkObject(fp,val) == 0) goto werr;
                    }
                    dictReleaseIterator(di);
                }
            } else {
                redisPanic("Unknown object type");
            }
            /* Save the expire time */
            if (expiretime != -1) {
                char cmd[]="*3\r\n$8\r\nEXPIREAT\r\n";
                /* If this key is already expired skip it */
                if (expiretime < now) continue;
                if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
                if (fwriteBulkObject(fp,&key) == 0) goto werr;
                if (fwriteBulkLongLong(fp,expiretime) == 0) goto werr;
            }
            if (swapped) decrRefCount(o);
        }
        dictReleaseIterator(di);
    }

    /* Make sure data will not remain on the OS's output buffers */
    fflush(fp);
    aof_fsync(fileno(fp));
    fclose(fp);

    /* Use RENAME to make sure the DB file is changed atomically only
     * if the generate DB file is ok. */
    if (rename(tmpfile,filename) == -1) {
        redisLog(REDIS_WARNING,"Error moving temp append only file on the final destination: %s", strerror(errno));
        unlink(tmpfile);
        return REDIS_ERR;
    }
    redisLog(REDIS_NOTICE,"SYNC append only file rewrite performed");
    return REDIS_OK;

werr:
    fclose(fp);
    unlink(tmpfile);
    redisLog(REDIS_WARNING,"Write error writing append only file on disk: %s", strerror(errno));
    if (di) dictReleaseIterator(di);
    return REDIS_ERR;
}
Exemple #18
0
/* Emit the commands needed to rebuild a sorted set object.
 * The function returns 0 on error, 1 on success. */
int rewriteSortedSetObject(rio *r, robj *key, robj *o) {
    long long count = 0, items = zsetLength(o);

    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
        unsigned char *zl = o->ptr;
        unsigned char *eptr, *sptr;
        unsigned char *vstr;
        unsigned int vlen;
        long long vll;
        double score;

        eptr = ziplistIndex(zl,0);
        redisAssert(eptr != NULL);
        sptr = ziplistNext(zl,eptr);
        redisAssert(sptr != NULL);

        while (eptr != NULL) {
            redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
            score = zzlGetScore(sptr);

            if (count == 0) {
                int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ?
                    REDIS_AOF_REWRITE_ITEMS_PER_CMD : items;

                if (rioWriteBulkCount(r,'*',2+cmd_items*2) == 0) return 0;
                if (rioWriteBulkString(r,"ZADD",4) == 0) return 0;
                if (rioWriteBulkObject(r,key) == 0) return 0;
            }
            if (rioWriteBulkDouble(r,score) == 0) return 0;
            if (vstr != NULL) {
                if (rioWriteBulkString(r,(char*)vstr,vlen) == 0) return 0;
            } else {
                if (rioWriteBulkLongLong(r,vll) == 0) return 0;
            }
            zzlNext(zl,&eptr,&sptr);
            if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0;
            items--;
        }
    } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
        zset *zs = o->ptr;
        dictIterator *di = dictGetIterator(zs->dict);
        dictEntry *de;

        while((de = dictNext(di)) != NULL) {
            robj *eleobj = dictGetKey(de);
            double *score = dictGetVal(de);

            if (count == 0) {
                int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ?
                    REDIS_AOF_REWRITE_ITEMS_PER_CMD : items;

                if (rioWriteBulkCount(r,'*',2+cmd_items*2) == 0) return 0;
                if (rioWriteBulkString(r,"ZADD",4) == 0) return 0;
                if (rioWriteBulkObject(r,key) == 0) return 0;
            }
            if (rioWriteBulkDouble(r,*score) == 0) return 0;
            if (rioWriteBulkObject(r,eleobj) == 0) return 0;
            if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0;
            items--;
        }
        dictReleaseIterator(di);
    } else {
        redisPanic("Unknown sorted zset encoding");
    }
    return 1;
}
Exemple #19
0
int 
main(int argc, char *argv[])
{
    unsigned char *zl, *p;
    unsigned char *entry;
    unsigned int elen;
    long long value;

    /* If an argument is given, use it as the random seed. */
    if (argc == 2)
        srand(atoi(argv[1]));

    zl = createIntList();
    ziplistRepr(zl);

    zl = createList();
    ziplistRepr(zl);

    pop(zl,ZIPLIST_TAIL);
    ziplistRepr(zl);

    pop(zl,ZIPLIST_HEAD);
    ziplistRepr(zl);

    pop(zl,ZIPLIST_TAIL);
    ziplistRepr(zl);

    pop(zl,ZIPLIST_TAIL);
    ziplistRepr(zl);

    printf("Get element at index 3:\n");
    {
        zl = createList();
        p = ziplistIndex(zl, 3);
        if (!ziplistGet(p, &entry, &elen, &value)) {
            printf("ERROR: Could not access index 3\n");
            return 1;
        }
        if (entry) {
            if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            printf("\n");
        } else {
            printf("%lld\n", value);
        }
        printf("\n");
    }

    printf("Get element at index 4 (out of range):\n");
    {
        zl = createList();
        p = ziplistIndex(zl, 4);
        if (p == NULL) {
            printf("No entry\n");
        } else {
            printf("ERROR: Out of range index should return NULL, returned offset: %ld\n", p-zl);
            return 1;
        }
        printf("\n");
    }

    printf("Get element at index -1 (last element):\n");
    {
        zl = createList();
        p = ziplistIndex(zl, -1);
        if (!ziplistGet(p, &entry, &elen, &value)) {
            printf("ERROR: Could not access index -1\n");
            return 1;
        }
        if (entry) {
            if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            printf("\n");
        } else {
            printf("%lld\n", value);
        }
        printf("\n");
    }

    printf("Get element at index -4 (first element):\n");
    {
        zl = createList();
        p = ziplistIndex(zl, -4);
        if (!ziplistGet(p, &entry, &elen, &value)) {
            printf("ERROR: Could not access index -4\n");
            return 1;
        }
        if (entry) {
            if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            printf("\n");
        } else {
            printf("%lld\n", value);
        }
        printf("\n");
    }

    printf("Get element at index -5 (reverse out of range):\n");
    {
        zl = createList();
        p = ziplistIndex(zl, -5);
        if (p == NULL) {
            printf("No entry\n");
        } else {
            printf("ERROR: Out of range index should return NULL, returned offset: %ld\n", p-zl);
            return 1;
        }
        printf("\n");
    }

    printf("Iterate list from 0 to end:\n");
    {
        zl = createList();
        p = ziplistIndex(zl, 0);
        while (ziplistGet(p, &entry, &elen, &value)) {
            printf("Entry: ");
            if (entry) {
                if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            } else {
                printf("%lld", value);
            }
            p = ziplistNext(zl,p);
            printf("\n");
        }
        printf("\n");
    }

    printf("Iterate list from 1 to end:\n");
    {
        zl = createList();
        p = ziplistIndex(zl, 1);
        while (ziplistGet(p, &entry, &elen, &value)) {
            printf("Entry: ");
            if (entry) {
                if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            } else {
                printf("%lld", value);
            }
            p = ziplistNext(zl,p);
            printf("\n");
        }
        printf("\n");
    }

    printf("Iterate list from 2 to end:\n");
    {
        zl = createList();
        p = ziplistIndex(zl, 2);
        while (ziplistGet(p, &entry, &elen, &value)) {
            printf("Entry: ");
            if (entry) {
                if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            } else {
                printf("%lld", value);
            }
            p = ziplistNext(zl,p);
            printf("\n");
        }
        printf("\n");
    }

    printf("Iterate starting out of range:\n");
    {
        zl = createList();
        p = ziplistIndex(zl, 4);
        if (!ziplistGet(p, &entry, &elen, &value)) {
            printf("No entry\n");
        } else {
            printf("ERROR\n");
        }
        printf("\n");
    }

    printf("Iterate from back to front:\n");
    {
        zl = createList();
        p = ziplistIndex(zl, -1);
        while (ziplistGet(p, &entry, &elen, &value)) {
            printf("Entry: ");
            if (entry) {
                if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            } else {
                printf("%lld", value);
            }
            p = ziplistPrev(zl,p);
            printf("\n");
        }
        printf("\n");
    }

    printf("Iterate from back to front, deleting all items:\n");
    {
        zl = createList();
        p = ziplistIndex(zl, -1);
        while (ziplistGet(p, &entry, &elen, &value)) {
            printf("Entry: ");
            if (entry) {
                if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
            } else {
                printf("%lld", value);
            }
            zl = ziplistDelete(zl,&p);
            p = ziplistPrev(zl,p);
            printf("\n");
        }
        printf("\n");
    }

    printf("Delete inclusive range 0,0:\n");
    {
        zl = createList();
        zl = ziplistDeleteRange(zl, 0, 1);
        ziplistRepr(zl);
    }

    printf("Delete inclusive range 0,1:\n");
    {
        zl = createList();
        zl = ziplistDeleteRange(zl, 0, 2);
        ziplistRepr(zl);
    }

    printf("Delete inclusive range 1,2:\n");
    {
        zl = createList();
        zl = ziplistDeleteRange(zl, 1, 2);
        ziplistRepr(zl);
    }

    printf("Delete with start index out of range:\n");
    {
        zl = createList();
        zl = ziplistDeleteRange(zl, 5, 1);
        ziplistRepr(zl);
    }

    printf("Delete with num overflow:\n");
    {
        zl = createList();
        zl = ziplistDeleteRange(zl, 1, 5);
        ziplistRepr(zl);
    }

    printf("Delete foo while iterating:\n");
    {
        zl = createList();
        p = ziplistIndex(zl,0);
        while (ziplistGet(p,&entry,&elen,&value)) {
            if (entry && strncmp("foo",(char*)entry,elen) == 0) {
                printf("Delete foo\n");
                zl = ziplistDelete(zl,&p);
            } else {
                printf("Entry: ");
                if (entry) {
                    if (elen && fwrite(entry,elen,1,stdout) == 0)
                        perror("fwrite");
                } else {
                    printf("%lld",value);
                }
                p = ziplistNext(zl,p);
                printf("\n");
            }
        }
        printf("\n");
        ziplistRepr(zl);
    }

    printf("Regression test for >255 byte strings:\n");
    {
        char v1[257],v2[257];
        memset(v1,'x',256);
        memset(v2,'y',256);
        zl = ziplistNew();
        zl = ziplistPush(zl,(unsigned char*)v1,strlen(v1),ZIPLIST_TAIL);
        zl = ziplistPush(zl,(unsigned char*)v2,strlen(v2),ZIPLIST_TAIL);

        /* Pop values again and compare their value. */
        p = ziplistIndex(zl,0);
        assert(ziplistGet(p,&entry,&elen,&value));
        assert(strncmp(v1,(char*)entry,elen) == 0);
        p = ziplistIndex(zl,1);
        assert(ziplistGet(p,&entry,&elen,&value));
        assert(strncmp(v2,(char*)entry,elen) == 0);
        printf("SUCCESS\n\n");
    }

    printf("Regression test deleting next to last entries:\n");
    {
        char v[3][257];
        zlentry e[3];
        int i;

        for (i = 0; i < (sizeof(v)/sizeof(v[0])); i++) {
            memset(v[i], 'a' + i, sizeof(v[0]));
        }

        v[0][256] = '\0';
        v[1][  1] = '\0';
        v[2][256] = '\0';

        zl = ziplistNew();
        for (i = 0; i < (sizeof(v)/sizeof(v[0])); i++) {
            zl = ziplistPush(zl, (unsigned char *) v[i], strlen(v[i]), ZIPLIST_TAIL);
        }

        verify(zl, e);

        assert(e[0].prevrawlensize == 1);
        assert(e[1].prevrawlensize == 5);
        assert(e[2].prevrawlensize == 1);

        /* Deleting entry 1 will increase `prevrawlensize` for entry 2 */
        unsigned char *p = e[1].p;
        zl = ziplistDelete(zl, &p);

        verify(zl, e);

        assert(e[0].prevrawlensize == 1);
        assert(e[1].prevrawlensize == 5);

        printf("SUCCESS\n\n");
    }

    printf("Create long list and check indices:\n");
    {
        zl = ziplistNew();
        char buf[32];
        int i,len;
        for (i = 0; i < 1000; i++) {
            len = sprintf(buf,"%d",i);
            zl = ziplistPush(zl,(unsigned char*)buf,len,ZIPLIST_TAIL);
        }
        for (i = 0; i < 1000; i++) {
            p = ziplistIndex(zl,i);
            assert(ziplistGet(p,NULL,NULL,&value));
            assert(i == value);

            p = ziplistIndex(zl,-i-1);
            assert(ziplistGet(p,NULL,NULL,&value));
            assert(999-i == value);
        }
        printf("SUCCESS\n\n");
    }

    printf("Compare strings with ziplist entries:\n");
    {
        zl = createList();
        p = ziplistIndex(zl,0);
        if (!ziplistCompare(p,(unsigned char*)"hello",5)) {
            printf("ERROR: not \"hello\"\n");
            return 1;
        }
        if (ziplistCompare(p,(unsigned char*)"hella",5)) {
            printf("ERROR: \"hella\"\n");
            return 1;
        }

        p = ziplistIndex(zl,3);
        if (!ziplistCompare(p,(unsigned char*)"1024",4)) {
            printf("ERROR: not \"1024\"\n");
            return 1;
        }
        if (ziplistCompare(p,(unsigned char*)"1025",4)) {
            printf("ERROR: \"1025\"\n");
            return 1;
        }
        printf("SUCCESS\n\n");
    }

    printf("Stress with random payloads of different encoding:\n");
    {
        int i,j,len,where;
        unsigned char *p;
        char buf[1024];
        int buflen;
        list *ref;
        listNode *refnode;

        /* Hold temp vars from ziplist */
        unsigned char *sstr;
        unsigned int slen;
        long long sval;

        for (i = 0; i < 20000; i++) {
            zl = ziplistNew();
            ref = listCreate();
            listSetFreeMethod(ref, sdsfree);
            len = rand() % 256;

            /* Create lists */
            for (j = 0; j < len; j++) {
                where = (rand() & 1) ? ZIPLIST_HEAD : ZIPLIST_TAIL;
                if (rand() % 2) {
                    buflen = randstring(buf,1,sizeof(buf)-1);
                } else {
                    switch(rand() % 3) {
                    case 0:
                        buflen = sprintf(buf,"%lld",(0LL + rand()) >> 20);
                        break;
                    case 1:
                        buflen = sprintf(buf,"%lld",(0LL + rand()));
                        break;
                    case 2:
                        buflen = sprintf(buf,"%lld",(0LL + rand()) << 20);
                        break;
                    default:
                        assert(NULL);
                    }
                }

                /* Add to ziplist */
                zl = ziplistPush(zl, (unsigned char*)buf, buflen, where);

                /* Add to reference list */
                if (where == ZIPLIST_HEAD) {
                    listAddNodeHead(ref,sdsnewlen(buf, buflen));
                } else if (where == ZIPLIST_TAIL) {
                    listAddNodeTail(ref,sdsnewlen(buf, buflen));
                } else {
                    assert(NULL);
                }
            }

            assert(listLength(ref) == ziplistLen(zl));
            for (j = 0; j < len; j++) {
                /* Naive way to get elements, but similar to the stresser
                 * executed from the Tcl test suite. */
                p = ziplistIndex(zl,j);
                refnode = listIndex(ref,j);

                assert(ziplistGet(p,&sstr,&slen,&sval));
                if (sstr == NULL) {
                    buflen = sprintf(buf,"%lld",sval);
                } else {
                    buflen = slen;
                    memcpy(buf,sstr,buflen);
                    buf[buflen] = '\0';
                }
                assert(memcmp(buf,listNodeValue(refnode),buflen) == 0);
            }
            zfree(zl);
            listRelease(ref);
        }
        printf("SUCCESS\n\n");
    }

    printf("Stress with variable ziplist size:\n");
    {
        stress(ZIPLIST_HEAD,100000,16384,256);
        stress(ZIPLIST_TAIL,100000,16384,256);
    }

    return 0;
}
Exemple #20
0
/* This command implements SCAN, HSCAN and SSCAN commands.
 * If object 'o' is passed, then it must be a Hash or Set object, otherwise
 * if 'o' is NULL the command will operate on the dictionary associated with
 * the current database.
 *
 * When 'o' is not NULL the function assumes that the first argument in
 * the client arguments vector is a key so it skips it before iterating
 * in order to parse options.
 *
 * In the case of a Hash object the function returns both the field and value
 * of every element on the Hash. */
void scanGenericCommand(client *c, robj *o, unsigned long cursor) {
    int i, j;
    list *keys = listCreate();
    listNode *node, *nextnode;
    long count = 10;
    sds pat = NULL;
    int patlen = 0, use_pattern = 0;
    dict *ht;

    /* Object must be NULL (to iterate keys names), or the type of the object
     * must be Set, Sorted Set, or Hash. */
    serverAssert(o == NULL || o->type == OBJ_SET || o->type == OBJ_HASH ||
                o->type == OBJ_ZSET);

    /* Set i to the first option argument. The previous one is the cursor. */
    i = (o == NULL) ? 2 : 3; /* Skip the key argument if needed. */

    /* Step 1: Parse options. */
    while (i < c->argc) {
        j = c->argc - i;
        if (!strcasecmp(c->argv[i]->ptr, "count") && j >= 2) {
            if (getLongFromObjectOrReply(c, c->argv[i+1], &count, NULL)
                != C_OK)
            {
                goto cleanup;
            }

            if (count < 1) {
                addReply(c,shared.syntaxerr);
                goto cleanup;
            }

            i += 2;
        } else if (!strcasecmp(c->argv[i]->ptr, "match") && j >= 2) {
            pat = c->argv[i+1]->ptr;
            patlen = sdslen(pat);

            /* The pattern always matches if it is exactly "*", so it is
             * equivalent to disabling it. */
            use_pattern = !(pat[0] == '*' && patlen == 1);

            i += 2;
        } else {
            addReply(c,shared.syntaxerr);
            goto cleanup;
        }
    }

    /* Step 2: Iterate the collection.
     *
     * Note that if the object is encoded with a ziplist, intset, or any other
     * representation that is not a hash table, we are sure that it is also
     * composed of a small number of elements. So to avoid taking state we
     * just return everything inside the object in a single call, setting the
     * cursor to zero to signal the end of the iteration. */

    /* Handle the case of a hash table. */
    ht = NULL;
    if (o == NULL) {
        ht = c->db->dict;
    } else if (o->type == OBJ_SET && o->encoding == OBJ_ENCODING_HT) {
        ht = o->ptr;
    } else if (o->type == OBJ_HASH && o->encoding == OBJ_ENCODING_HT) {
        ht = o->ptr;
        count *= 2; /* We return key / value for this type. */
    } else if (o->type == OBJ_ZSET && o->encoding == OBJ_ENCODING_SKIPLIST) {
        zset *zs = o->ptr;
        ht = zs->dict;
        count *= 2; /* We return key / value for this type. */
    }

    if (ht) {
        void *privdata[2];
        /* We set the max number of iterations to ten times the specified
         * COUNT, so if the hash table is in a pathological state (very
         * sparsely populated) we avoid to block too much time at the cost
         * of returning no or very few elements. */
        long maxiterations = count*10;

        /* We pass two pointers to the callback: the list to which it will
         * add new elements, and the object containing the dictionary so that
         * it is possible to fetch more data in a type-dependent way. */
        privdata[0] = keys;
        privdata[1] = o;
        do {
            cursor = dictScan(ht, cursor, scanCallback, privdata);
        } while (cursor &&
              maxiterations-- &&
              listLength(keys) < (unsigned long)count);
    } else if (o->type == OBJ_SET) {
        int pos = 0;
        int64_t ll;

        while(intsetGet(o->ptr,pos++,&ll))
            listAddNodeTail(keys,createStringObjectFromLongLong(ll));
        cursor = 0;
    } else if (o->type == OBJ_HASH || o->type == OBJ_ZSET) {
        unsigned char *p = ziplistIndex(o->ptr,0);
        unsigned char *vstr;
        unsigned int vlen;
        long long vll;

        while(p) {
            ziplistGet(p,&vstr,&vlen,&vll);
            listAddNodeTail(keys,
                (vstr != NULL) ? createStringObject((char*)vstr,vlen) :
                                 createStringObjectFromLongLong(vll));
            p = ziplistNext(o->ptr,p);
        }
        cursor = 0;
    } else {
        serverPanic("Not handled encoding in SCAN.");
    }

    /* Step 3: Filter elements. */
    node = listFirst(keys);
    while (node) {
        robj *kobj = listNodeValue(node);
        nextnode = listNextNode(node);
        int filter = 0;

        /* Filter element if it does not match the pattern. */
        if (!filter && use_pattern) {
            if (sdsEncodedObject(kobj)) {
                if (!stringmatchlen(pat, patlen, kobj->ptr, sdslen(kobj->ptr), 0))
                    filter = 1;
            } else {
                char buf[LONG_STR_SIZE];
                int len;

                serverAssert(kobj->encoding == OBJ_ENCODING_INT);
                len = ll2string(buf,sizeof(buf),(long)kobj->ptr);
                if (!stringmatchlen(pat, patlen, buf, len, 0)) filter = 1;
            }
        }

        /* Filter element if it is an expired key. */
        if (!filter && o == NULL && expireIfNeeded(c->db, kobj)) filter = 1;

        /* Remove the element and its associted value if needed. */
        if (filter) {
            decrRefCount(kobj);
            listDelNode(keys, node);
        }

        /* If this is a hash or a sorted set, we have a flat list of
         * key-value elements, so if this element was filtered, remove the
         * value, or skip it if it was not filtered: we only match keys. */
        if (o && (o->type == OBJ_ZSET || o->type == OBJ_HASH)) {
            node = nextnode;
            nextnode = listNextNode(node);
            if (filter) {
                kobj = listNodeValue(node);
                decrRefCount(kobj);
                listDelNode(keys, node);
            }
        }
        node = nextnode;
    }

    /* Step 4: Reply to the client. */
    addReplyMultiBulkLen(c, 2);
    addReplyBulkLongLong(c,cursor);

    addReplyMultiBulkLen(c, listLength(keys));
    while ((node = listFirst(keys)) != NULL) {
        robj *kobj = listNodeValue(node);
        addReplyBulk(c, kobj);
        decrRefCount(kobj);
        listDelNode(keys, node);
    }

cleanup:
    listSetFreeMethod(keys,decrRefCountVoid);
    listRelease(keys);
}