void keysCommand(redisClient *c) { dictIterator *di; dictEntry *de; sds pattern = c->argv[1]->ptr; int plen = sdslen(pattern), allkeys; unsigned long numkeys = 0; void *replylen = addDeferredMultiBulkLength(c); di = dictGetSafeIterator(c->db->dict); allkeys = (pattern[0] == '*' && pattern[1] == '\0'); while((de = dictNext(di)) != NULL) { sds key = dictGetKey(de); robj *keyobj; if (allkeys || stringmatchlen(pattern,plen,key,sdslen(key),0)) { keyobj = createStringObject(key,sdslen(key)); if (expireIfNeeded(c->db,keyobj) == 0) { addReplyBulk(c,keyobj); numkeys++; } decrRefCount(keyobj); } } dictReleaseIterator(di); setDeferredMultiBulkLength(c,replylen,numkeys); }
/* Output the representation of a Redis command. Used by the COMMAND command. */ static void addReplyCommand(client *c, struct redisCommand *cmd) { if (!cmd) { addReply(c, shared.nullbulk); } else { /* We are adding: command name, arg count, flags, first, last, offset */ addReplyMultiBulkLen(c, 6); addReplyBulkCString(c, cmd->name); addReplyLongLong(c, cmd->arity); int flagcount = 0; void *flaglen = addDeferredMultiBulkLength(c); flagcount += addReplyCommandFlag(c,cmd,CMD_WRITE, "write"); flagcount += addReplyCommandFlag(c,cmd,CMD_READONLY, "readonly"); flagcount += addReplyCommandFlag(c,cmd,CMD_DENYOOM, "denyoom"); flagcount += addReplyCommandFlag(c,cmd,CMD_ADMIN, "admin"); flagcount += addReplyCommandFlag(c,cmd,CMD_PUBSUB, "pubsub"); flagcount += addReplyCommandFlag(c,cmd,CMD_NOSCRIPT, "noscript"); flagcount += addReplyCommandFlag(c,cmd,CMD_RANDOM, "random"); flagcount += addReplyCommandFlag(c,cmd,CMD_SORT_FOR_SCRIPT,"sort_for_script"); flagcount += addReplyCommandFlag(c,cmd,CMD_LOADING, "loading"); flagcount += addReplyCommandFlag(c,cmd,CMD_STALE, "stale"); flagcount += addReplyCommandFlag(c,cmd,CMD_SKIP_MONITOR, "skip_monitor"); flagcount += addReplyCommandFlag(c,cmd,CMD_ASKING, "asking"); flagcount += addReplyCommandFlag(c,cmd,CMD_FAST, "fast"); if (cmd->getkeys_proc) { addReplyStatus(c, "movablekeys"); flagcount += 1; } setDeferredMultiBulkLength(c, flaglen, flagcount); addReplyLongLong(c, cmd->firstkey); addReplyLongLong(c, cmd->lastkey); addReplyLongLong(c, cmd->keystep); } }
/* PUBSUB command for Pub/Sub introspection. */ void pubsubCommand(redisClient *c) { // 处理PUBSUB CHANNELS [pattern]命令 if (!strcasecmp(c->argv[1]->ptr,"channels") && (c->argc == 2 || c->argc ==3)) { /* PUBSUB CHANNELS [<pattern>] */ // 获取pattern参数,如果没有则为NULL sds pat = (c->argc == 2) ? NULL : c->argv[2]->ptr; dictIterator *di = dictGetIterator(server.pubsub_channels); dictEntry *de; long mblen = 0; void *replylen; replylen = addDeferredMultiBulkLength(c); // 遍历server.pubsub_channels字典 while((de = dictNext(di)) != NULL) { // 取出当前频道channel robj *cobj = dictGetKey(de); sds channel = cobj->ptr; // 如果没有给定pattern参数,则打印出所有频道 // 如果给定pattern参数,则打印出与pattern参数相匹配的频道 if (!pat || stringmatchlen(pat, sdslen(pat), channel, sdslen(channel),0)) { addReplyBulk(c,cobj); mblen++; } } dictReleaseIterator(di); setDeferredMultiBulkLength(c,replylen,mblen); } // 处理PUBSUB NUMSUB [Channel_1 ... Channel_N]命令 else if (!strcasecmp(c->argv[1]->ptr,"numsub") && c->argc >= 2) { /* PUBSUB NUMSUB [Channel_1 ... Channel_N] */ int j; addReplyMultiBulkLen(c,(c->argc-2)*2); for (j = 2; j < c->argc; j++) { list *l = dictFetchValue(server.pubsub_channels,c->argv[j]); addReplyBulk(c,c->argv[j]); addReplyLongLong(c,l ? listLength(l) : 0); } } // 处理PUBSUB NUMPA命令 else if (!strcasecmp(c->argv[1]->ptr,"numpat") && c->argc == 2) { /* PUBSUB NUMPAT */ addReplyLongLong(c,listLength(server.pubsub_patterns)); } else { addReplyErrorFormat(c, "Unknown PUBSUB subcommand or wrong number of arguments for '%s'", (char*)c->argv[1]->ptr); } }
/* The SLOWLOG command. Implements all the subcommands needed to handle the * Redis slow log. * * SLOWLOG 命令的实现,支持 GET / RESET 和 LEN 参数 */ void slowlogCommand(redisClient *c) { // 重置 if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr,"reset")) { slowlogReset(); addReply(c,shared.ok); // 返回长度 } else if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr,"len")) { addReplyLongLong(c,listLength(server.slowlog)); // 获取某条或者全部日志 } else if ((c->argc == 2 || c->argc == 3) && !strcasecmp(c->argv[1]->ptr,"get")) { long count = 10, sent = 0; listIter li; void *totentries; listNode *ln; slowlogEntry *se; if (c->argc == 3 && getLongFromObjectOrReply(c,c->argv[2],&count,NULL) != REDIS_OK) return; // 遍历日志,取出指定数量的日志 listRewind(server.slowlog,&li); totentries = addDeferredMultiBulkLength(c); while(count-- && (ln = listNext(&li))) { int j; se = ln->value; addReplyMultiBulkLen(c,4); addReplyLongLong(c,se->id); addReplyLongLong(c,se->time); addReplyLongLong(c,se->duration); addReplyMultiBulkLen(c,se->argc); for (j = 0; j < se->argc; j++) addReplyBulk(c,se->argv[j]); sent++; } setDeferredMultiBulkLength(c,totentries,sent); } else { addReplyError(c, "Unknown SLOWLOG subcommand or wrong # of args. Try GET, RESET, LEN."); } }
/* latencyCommand() helper to produce a time-delay reply for all the samples * in memory for the specified time series. */ void latencyCommandReplyWithSamples(client *c, struct latencyTimeSeries *ts) { void *replylen = addDeferredMultiBulkLength(c); int samples = 0, j; for (j = 0; j < LATENCY_TS_LEN; j++) { int i = (ts->idx + j) % LATENCY_TS_LEN; if (ts->samples[i].time == 0) continue; addReplyMultiBulkLen(c,2); addReplyLongLong(c,ts->samples[i].time); addReplyLongLong(c,ts->samples[i].latency); samples++; } setDeferredMultiBulkLength(c,replylen,samples); }
/* * PUBSUB 命令, 内省命令 */ void pubsubCommand(redisClient *c) { if (!strcasecmp(c->argv[1]->ptr,"channels") && (c->argc == 2 || c->argc ==3)) //列出当前活跃的频道,每个频道至少有一个订阅者,订阅模式的客户端不计算在内 { /* PUBSUB CHANNELS [<pattern>] */ sds pat = (c->argc == 2) ? NULL : c->argv[2]->ptr; dictIterator *di = dictGetIterator(server.pubsub_channels); dictEntry *de; long mblen = 0; void *replylen; replylen = addDeferredMultiBulkLength(c); while((de = dictNext(di)) != NULL) { robj *cobj = dictGetKey(de); sds channel = cobj->ptr; if (!pat || stringmatchlen(pat, sdslen(pat), channel, sdslen(channel),0)) { addReplyBulk(c,cobj); mblen++; } } dictReleaseIterator(di); setDeferredMultiBulkLength(c,replylen,mblen); } else if (!strcasecmp(c->argv[1]->ptr,"numsub") && c->argc >= 2) { //返回给定频道的订阅者数量,订阅模式的客户端不计算在内 /* PUBSUB NUMSUB [Channel_1 ... Channel_N] */ int j; addReplyMultiBulkLen(c,(c->argc-2)*2); for (j = 2; j < c->argc; j++) { list *l = dictFetchValue(server.pubsub_channels,c->argv[j]); addReplyBulk(c,c->argv[j]); addReplyLongLong(c,l ? listLength(l) : 0); } } else if (!strcasecmp(c->argv[1]->ptr,"numpat") && c->argc == 2) { //返回订阅模式的数量 /* PUBSUB NUMPAT */ addReplyLongLong(c,listLength(server.pubsub_patterns)); } else { addReplyErrorFormat(c, "Unknown PUBSUB subcommand or wrong number of arguments for '%s'", (char*)c->argv[1]->ptr); } }
void luaReplyToRedisReply(redisClient *c, lua_State *lua) { int t = lua_type(lua,-1); switch(t) { case LUA_TSTRING: addReplyBulkCBuffer(c,(char*)lua_tostring(lua,-1),lua_strlen(lua,-1)); break; case LUA_TBOOLEAN: addReply(c,lua_toboolean(lua,-1) ? shared.cone : shared.nullbulk); break; case LUA_TNUMBER: addReplyLongLong(c,(long long)lua_tonumber(lua,-1)); break; case LUA_TTABLE: /* We need to check if it is an array, an error, or a status reply. * Error are returned as a single element table with 'err' field. * Status replies are returned as single element table with 'ok' field */ lua_pushstring(lua,"err"); lua_gettable(lua,-2); t = lua_type(lua,-1); if (t == LUA_TSTRING) { sds err = sdsnew(lua_tostring(lua,-1)); sdsmapchars(err,"\r\n"," ",2); addReplySds(c,sdscatprintf(sdsempty(),"-%s\r\n",err)); sdsfree(err); lua_pop(lua,2); return; } lua_pop(lua,1); lua_pushstring(lua,"ok"); lua_gettable(lua,-2); t = lua_type(lua,-1); if (t == LUA_TSTRING) { sds ok = sdsnew(lua_tostring(lua,-1)); sdsmapchars(ok,"\r\n"," ",2); addReplySds(c,sdscatprintf(sdsempty(),"+%s\r\n",ok)); sdsfree(ok); lua_pop(lua,1); } else { void *replylen = addDeferredMultiBulkLength(c); int j = 1, mbulklen = 0; lua_pop(lua,1); /* Discard the 'ok' field value we popped */ while(1) { lua_pushnumber(lua,j++); lua_gettable(lua,-2); t = lua_type(lua,-1); if (t == LUA_TNIL) { lua_pop(lua,1); break; } luaReplyToRedisReply(c, lua); mbulklen++; } setDeferredMultiBulkLength(c,replylen,mbulklen); } break; default: addReply(c,shared.nullbulk); } lua_pop(lua,1); }
/* This command implements ZRANGEBYSCORE, ZREVRANGEBYSCORE and ZCOUNT. * If "justcount", only the number of elements in the range is returned. */ void genericZrangebyscoreCommand(redisClient *c, int reverse, int justcount) { zrangespec range; robj *o, *emptyreply; zset *zsetobj; zskiplist *zsl; zskiplistNode *ln; int offset = 0, limit = -1; int withscores = 0; unsigned long rangelen = 0; void *replylen = NULL; /* Parse the range arguments. */ if (zslParseRange(c->argv[2],c->argv[3],&range) != REDIS_OK) { addReplyError(c,"min or max is not a double"); return; } /* Parse optional extra arguments. Note that ZCOUNT will exactly have * 4 arguments, so we'll never enter the following code path. */ if (c->argc > 4) { int remaining = c->argc - 4; int pos = 4; while (remaining) { if (remaining >= 1 && !strcasecmp(c->argv[pos]->ptr,"withscores")) { pos++; remaining--; withscores = 1; } else if (remaining >= 3 && !strcasecmp(c->argv[pos]->ptr,"limit")) { offset = atoi(c->argv[pos+1]->ptr); limit = atoi(c->argv[pos+2]->ptr); pos += 3; remaining -= 3; } else { addReply(c,shared.syntaxerr); return; } } } /* Ok, lookup the key and get the range */ emptyreply = justcount ? shared.czero : shared.emptymultibulk; if ((o = lookupKeyReadOrReply(c,c->argv[1],emptyreply)) == NULL || checkType(c,o,REDIS_ZSET)) return; zsetobj = o->ptr; zsl = zsetobj->zsl; /* If reversed, assume the elements are sorted from high to low score. */ ln = zslFirstWithScore(zsl,range.min); if (reverse) { /* If range.min is out of range, ln will be NULL and we need to use * the tail of the skiplist as first node of the range. */ if (ln == NULL) ln = zsl->tail; /* zslFirstWithScore returns the first element with where with * score >= range.min, so backtrack to make sure the element we use * here has score <= range.min. */ while (ln && ln->score > range.min) ln = ln->backward; /* Move to the right element according to the range spec. */ if (range.minex) { /* Find last element with score < range.min */ while (ln && ln->score == range.min) ln = ln->backward; } else { /* Find last element with score <= range.min */ while (ln && ln->level[0].forward && ln->level[0].forward->score == range.min) ln = ln->level[0].forward; } } else { if (range.minex) { /* Find first element with score > range.min */ while (ln && ln->score == range.min) ln = ln->level[0].forward; } } /* No "first" element in the specified interval. */ if (ln == NULL) { addReply(c,emptyreply); return; } /* We don't know in advance how many matching elements there * are in the list, so we push this object that will represent * the multi-bulk length in the output buffer, and will "fix" * it later */ if (!justcount) replylen = addDeferredMultiBulkLength(c); /* If there is an offset, just traverse the number of elements without * checking the score because that is done in the next loop. */ while(ln && offset--) { if (reverse) ln = ln->backward; else ln = ln->level[0].forward; } while (ln && limit--) { /* Check if this this element is in range. */ if (reverse) { if (range.maxex) { /* Element should have score > range.max */ if (ln->score <= range.max) break; } else { /* Element should have score >= range.max */ if (ln->score < range.max) break; } } else { if (range.maxex) { /* Element should have score < range.max */ if (ln->score >= range.max) break; } else { /* Element should have score <= range.max */ if (ln->score > range.max) break; } } /* Do our magic */ rangelen++; if (!justcount) { addReplyBulk(c,ln->obj); if (withscores) addReplyDouble(c,ln->score); } if (reverse) ln = ln->backward; else ln = ln->level[0].forward; } if (justcount) { addReplyLongLong(c,(long)rangelen); } else { setDeferredMultiBulkLength(c,replylen, withscores ? (rangelen*2) : rangelen); } }
void sinterGenericCommand(redisClient *c, robj **setkeys, unsigned long setnum, robj *dstkey) { robj **sets = zmalloc(sizeof(robj*)*setnum); setTypeIterator *si; robj *eleobj, *dstset = NULL; int64_t intobj; void *replylen = NULL; unsigned long j, cardinality = 0; int encoding; for (j = 0; j < setnum; j++) { robj *setobj = dstkey ? lookupKeyWrite(c->db,setkeys[j]) : lookupKeyRead(c->db,setkeys[j]); if (!setobj) { zfree(sets); if (dstkey) { if (dbDelete(c->db,dstkey)) { touchWatchedKey(c->db,dstkey); server.dirty++; } addReply(c,shared.czero); } else { addReply(c,shared.emptymultibulk); } return; } if (checkType(c,setobj,REDIS_SET)) { zfree(sets); return; } sets[j] = setobj; } /* Sort sets from the smallest to largest, this will improve our * algorithm's performace */ qsort(sets,setnum,sizeof(robj*),qsortCompareSetsByCardinality); /* The first thing we should output is the total number of elements... * since this is a multi-bulk write, but at this stage we don't know * the intersection set size, so we use a trick, append an empty object * to the output list and save the pointer to later modify it with the * right length */ if (!dstkey) { replylen = addDeferredMultiBulkLength(c); } else { /* If we have a target key where to store the resulting set * create this key with an empty set inside */ dstset = createIntsetObject(); } /* Iterate all the elements of the first (smallest) set, and test * the element against all the other sets, if at least one set does * not include the element it is discarded */ si = setTypeInitIterator(sets[0]); while((encoding = setTypeNext(si,&eleobj,&intobj)) != -1) { for (j = 1; j < setnum; j++) { if (encoding == REDIS_ENCODING_INTSET) { /* intset with intset is simple... and fast */ if (sets[j]->encoding == REDIS_ENCODING_INTSET && !intsetFind((intset*)sets[j]->ptr,intobj)) { break; /* in order to compare an integer with an object we * have to use the generic function, creating an object * for this */ } else if (sets[j]->encoding == REDIS_ENCODING_HT) { eleobj = createStringObjectFromLongLong(intobj); if (!setTypeIsMember(sets[j],eleobj)) { decrRefCount(eleobj); break; } decrRefCount(eleobj); } } else if (encoding == REDIS_ENCODING_HT) { /* Optimization... if the source object is integer * encoded AND the target set is an intset, we can get * a much faster path. */ if (eleobj->encoding == REDIS_ENCODING_INT && sets[j]->encoding == REDIS_ENCODING_INTSET && !intsetFind((intset*)sets[j]->ptr,(long)eleobj->ptr)) { break; /* else... object to object check is easy as we use the * type agnostic API here. */ } else if (!setTypeIsMember(sets[j],eleobj)) { break; } } } /* Only take action when all sets contain the member */ if (j == setnum) { if (!dstkey) { if (encoding == REDIS_ENCODING_HT) addReplyBulk(c,eleobj); else addReplyBulkLongLong(c,intobj); cardinality++; } else { if (encoding == REDIS_ENCODING_INTSET) { eleobj = createStringObjectFromLongLong(intobj); setTypeAdd(dstset,eleobj); decrRefCount(eleobj); } else { setTypeAdd(dstset,eleobj); } } } } setTypeReleaseIterator(si); if (dstkey) { /* Store the resulting set into the target, if the intersection * is not an empty set. */ dbDelete(c->db,dstkey); if (setTypeSize(dstset) > 0) { dbAdd(c->db,dstkey,dstset); addReplyLongLong(c,setTypeSize(dstset)); } else { decrRefCount(dstset); addReply(c,shared.czero); } touchWatchedKey(c->db,dstkey); server.dirty++; } else { setDeferredMultiBulkLength(c,replylen,cardinality); } zfree(sets); }
/* PUBSUB command for Pub/Sub introspection. */ void pubsubCommand(redisClient *c) { // PUBSUB CHANNELS [pattern] 子命令 if (!strcasecmp(c->argv[1]->ptr,"channels") && (c->argc == 2 || c->argc ==3)) { /* PUBSUB CHANNELS [<pattern>] */ // 检查命令请求是否给定了 pattern 参数 // 如果没有给定的话,就设为 NULL sds pat = (c->argc == 2) ? NULL : c->argv[2]->ptr; // 创建 pubsub_channels 的字典迭代器 // 该字典的键为频道,值为链表 // 链表中保存了所有订阅键所对应的频道的客户端 dictIterator *di = dictGetIterator(server.pubsub_channels); dictEntry *de; long mblen = 0; void *replylen; replylen = addDeferredMultiBulkLength(c); // 从迭代器中获取一个客户端 while((de = dictNext(di)) != NULL) { // 从字典中取出客户端所订阅的频道 robj *cobj = dictGetKey(de); sds channel = cobj->ptr; // 顺带一提 // 因为 Redis 的字典实现只能遍历字典的值(客户端) // 所以这里才会有遍历字典值然后通过字典值取出字典键(频道)的蹩脚用法 // 如果没有给定 pattern 参数,那么打印所有找到的频道 // 如果给定了 pattern 参数,那么只打印和 pattern 相匹配的频道 if (!pat || stringmatchlen(pat, sdslen(pat), channel, sdslen(channel),0)) { // 向客户端输出频道 addReplyBulk(c,cobj); mblen++; } } // 释放字典迭代器 dictReleaseIterator(di); setDeferredMultiBulkLength(c,replylen,mblen); // PUBSUB NUMSUB [channel-1 channel-2 ... channel-N] 子命令 } else if (!strcasecmp(c->argv[1]->ptr,"numsub") && c->argc >= 2) { /* PUBSUB NUMSUB [Channel_1 ... Channel_N] */ int j; addReplyMultiBulkLen(c,(c->argc-2)*2); for (j = 2; j < c->argc; j++) { // c->argv[j] 也即是客户端输入的第 N 个频道名字 // pubsub_channels 的字典为频道名字 // 而值则是保存了 c->argv[j] 频道所有订阅者的链表 // 而调用 dictFetchValue 也就是取出所有订阅给定频道的客户端 list *l = dictFetchValue(server.pubsub_channels,c->argv[j]); addReplyBulk(c,c->argv[j]); // 向客户端返回链表的长度属性 // 这个属性就是某个频道的订阅者数量 // 例如:如果一个频道有三个订阅者,那么链表的长度就是 3 // 而返回给客户端的数字也是三 addReplyBulkLongLong(c,l ? listLength(l) : 0); } // PUBSUB NUMPAT 子命令 } else if (!strcasecmp(c->argv[1]->ptr,"numpat") && c->argc == 2) { /* PUBSUB NUMPAT */ // pubsub_patterns 链表保存了服务器中所有被订阅的模式 // pubsub_patterns 的长度就是服务器中被订阅模式的数量 addReplyLongLong(c,listLength(server.pubsub_patterns)); // 错误处理 } else { addReplyErrorFormat(c, "Unknown PUBSUB subcommand or wrong number of arguments for '%s'", (char*)c->argv[1]->ptr); } }
/* BITPOS key [start end limit] */ static void bitallposCommand(redisClient *c) { robj *o; long start, end, limit = -1, strlen; void *replylen = NULL; unsigned char *p, byte; char llbuf[32]; unsigned long bytecount = 0; unsigned long bitcount = 0; /* Lookup, check for type, and return 0 for non existing keys. */ if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptymultibulk)) == NULL || checkType(c,o,REDIS_STRING)) return; /* Set the 'p' pointer to the string, that can be just a stack allocated * array if our string was integer encoded. */ if (o->encoding == REDIS_ENCODING_INT) { p = (unsigned char*) llbuf; strlen = ll2string(llbuf,sizeof(llbuf),(long)o->ptr); } else { p = (unsigned char*) o->ptr; strlen = sdslen(o->ptr); } /* Parse start/end range if any. */ if (c->argc == 5) { if (getLongFromObjectOrReply(c,c->argv[4],&limit,NULL) != REDIS_OK) return; } if (c->argc >= 4) { if (getLongFromObjectOrReply(c,c->argv[2],&start,NULL) != REDIS_OK) return; if (getLongFromObjectOrReply(c,c->argv[3],&end,NULL) != REDIS_OK) return; } else if (c->argc == 3) { if (getLongFromObjectOrReply(c,c->argv[2],&start,NULL) != REDIS_OK) return; end = strlen-1; } else if (c->argc == 2) { /* The whole string. */ start = 0; end = strlen-1; } else { /* Syntax error. */ addReply(c,shared.syntaxerr); return; } /* Convert negative indexes */ if (start < 0) start = strlen+start; if (end < 0) end = strlen+end; if (start < 0) start = 0; if (end < 0) end = 0; if (end >= strlen) end = strlen-1; /* Precondition: end >= 0 && end < strlen, so the only condition where * zero can be returned is: start > end. */ if (start > end) { addReply(c,shared.emptymultibulk); return; } p = (p + start); bytecount = (end - start + 1); replylen = addDeferredMultiBulkLength(c); /* iterate over bytes */ while (bytecount--) { unsigned int i = 128, pos = 0; byte = *p++; while (byte && limit) { if (byte & i) { addReplyBulkLongLong(c, (start * 8 + pos)); byte &= ~(1 << (7 - pos)); ++bitcount; --limit; limit = (((-1) > (limit)) ? (-1) : (limit)); } i >>= 1; pos++; } start++; } setDeferredMultiBulkLength(c, replylen, bitcount); }
void sinterGenericCommand(redisClient *c, robj **setkeys, unsigned long setnum, robj *dstkey) { robj **sets = zmalloc(sizeof(robj*)*setnum); setTypeIterator *si;//迭代器 robj *eleobj, *dstset = NULL; int64_t intobj; void *replylen = NULL; unsigned long j, cardinality = 0; int encoding; for (j = 0; j < setnum; j++) {//得到所有的集合 robj *setobj = dstkey ? lookupKeyWrite(c->db,setkeys[j]) : lookupKeyRead(c->db,setkeys[j]); if (!setobj) {//任何一个集合不存在,那么总的交集就为空 zfree(sets); if (dstkey) { if (dbDelete(c->db,dstkey)) { signalModifiedKey(c->db,dstkey); server.dirty++; } addReply(c,shared.czero); } else { addReply(c,shared.emptymultibulk); } return; } if (checkType(c,setobj,REDIS_SET)) { zfree(sets); return; } sets[j] = setobj; } /* Sort sets from the smallest to largest, this will improve our * algorithm's performance */ //按照集合元素个数从小到大排序 qsort(sets,setnum,sizeof(robj*),qsortCompareSetsByCardinality); /* The first thing we should output is the total number of elements... * since this is a multi-bulk write, but at this stage we don't know * the intersection set size, so we use a trick, append an empty object * to the output list and save the pointer to later modify it with the * right length */ if (!dstkey) { replylen = addDeferredMultiBulkLength(c); } else { /* If we have a target key where to store the resulting set * create this key with an empty set inside */ dstset = createIntsetObject(); } /* Iterate all the elements of the first (smallest) set, and test * the element against all the other sets, if at least one set does * not include the element it is discarded */ /** 求多个集合交集的算法思想: 首先按照集合元素个数对集合进行qsort,然后遍历排序后的第一个集合中的元素,查看该元素在 其他集合中是否存在,如果在其他集合中都存在,那么该元素为一个结果 */ si = setTypeInitIterator(sets[0]); while((encoding = setTypeNext(si,&eleobj,&intobj)) != -1) { for (j = 1; j < setnum; j++) { if (sets[j] == sets[0]) continue;//这段代码没意义啊 if (encoding == REDIS_ENCODING_INTSET) {//intset /* intset with intset is simple... and fast */ //集合sets[j]编码为intset if (sets[j]->encoding == REDIS_ENCODING_INTSET && !intsetFind((intset*)sets[j]->ptr,intobj))//在集合sets[j]中没有找到集合sets[0]的intobj { break; /* in order to compare an integer with an object we * have to use the generic function, creating an object * for this */ } else if (sets[j]->encoding == REDIS_ENCODING_HT) {//集合sets[j]编码为HT,sets[0]为INTSET eleobj = createStringObjectFromLongLong(intobj);//将sets[0]中的intobj转换为sds if (!setTypeIsMember(sets[j],eleobj)) {//如果eleobj不在集合sets[j]中 decrRefCount(eleobj); break; } decrRefCount(eleobj); } } else if (encoding == REDIS_ENCODING_HT) {//HT /* Optimization... if the source object is integer * encoded AND the target set is an intset, we can get * a much faster path. */ if (eleobj->encoding == REDIS_ENCODING_INT && sets[j]->encoding == REDIS_ENCODING_INTSET && !intsetFind((intset*)sets[j]->ptr,(long)eleobj->ptr)) { break; /* else... object to object check is easy as we use the * type agnostic API here. */ } else if (!setTypeIsMember(sets[j],eleobj)) { break; } } } /* Only take action when all sets contain the member */ if (j == setnum) { if (!dstkey) { if (encoding == REDIS_ENCODING_HT) addReplyBulk(c,eleobj); else addReplyBulkLongLong(c,intobj); cardinality++; } else {//添加到临时目标集合 if (encoding == REDIS_ENCODING_INTSET) { eleobj = createStringObjectFromLongLong(intobj); setTypeAdd(dstset,eleobj); decrRefCount(eleobj); } else { setTypeAdd(dstset,eleobj); } } } } setTypeReleaseIterator(si); if (dstkey) { /* Store the resulting set into the target, if the intersection * is not an empty set. */ int deleted = dbDelete(c->db,dstkey);//覆盖原来的目标集合 if (setTypeSize(dstset) > 0) { dbAdd(c->db,dstkey,dstset); addReplyLongLong(c,setTypeSize(dstset)); notifyKeyspaceEvent(REDIS_NOTIFY_SET,"sinterstore", dstkey,c->db->id); } else {//空集 decrRefCount(dstset); addReply(c,shared.czero); if (deleted) notifyKeyspaceEvent(REDIS_NOTIFY_GENERIC,"del", dstkey,c->db->id); } signalModifiedKey(c->db,dstkey); server.dirty++; } else { setDeferredMultiBulkLength(c,replylen,cardinality); } zfree(sets); }
void sinterGenericCommand(client *c, robj **setkeys, unsigned long setnum, robj *dstkey) { robj **sets = zmalloc(sizeof(robj*)*setnum); setTypeIterator *si; robj *dstset = NULL; sds elesds; int64_t intobj; void *replylen = NULL; unsigned long j, cardinality = 0; int encoding; for (j = 0; j < setnum; j++) { robj *setobj = dstkey ? lookupKeyWrite(c->db,setkeys[j]) : lookupKeyRead(c->db,setkeys[j]); if (!setobj) { zfree(sets); if (dstkey) { if (dbDelete(c->db,dstkey)) { signalModifiedKey(c->db,dstkey); server.dirty++; } addReply(c,shared.czero); } else { addReply(c,shared.emptymultibulk); } return; } if (checkType(c,setobj,OBJ_SET)) { zfree(sets); return; } sets[j] = setobj; } /* Sort sets from the smallest to largest, this will improve our * algorithm's performance */ qsort(sets,setnum,sizeof(robj*),qsortCompareSetsByCardinality); /* The first thing we should output is the total number of elements... * since this is a multi-bulk write, but at this stage we don't know * the intersection set size, so we use a trick, append an empty object * to the output list and save the pointer to later modify it with the * right length */ if (!dstkey) { replylen = addDeferredMultiBulkLength(c); } else { /* If we have a target key where to store the resulting set * create this key with an empty set inside */ dstset = createIntsetObject(); } /* Iterate all the elements of the first (smallest) set, and test * the element against all the other sets, if at least one set does * not include the element it is discarded */ si = setTypeInitIterator(sets[0]); while((encoding = setTypeNext(si,&elesds,&intobj)) != -1) { for (j = 1; j < setnum; j++) { if (sets[j] == sets[0]) continue; if (encoding == OBJ_ENCODING_INTSET) { /* intset with intset is simple... and fast */ if (sets[j]->encoding == OBJ_ENCODING_INTSET && !intsetFind((intset*)sets[j]->ptr,intobj)) { break; /* in order to compare an integer with an object we * have to use the generic function, creating an object * for this */ } else if (sets[j]->encoding == OBJ_ENCODING_HT) { elesds = sdsfromlonglong(intobj); if (!setTypeIsMember(sets[j],elesds)) { sdsfree(elesds); break; } sdsfree(elesds); } } else if (encoding == OBJ_ENCODING_HT) { if (!setTypeIsMember(sets[j],elesds)) { break; } } } /* Only take action when all sets contain the member */ if (j == setnum) { if (!dstkey) { if (encoding == OBJ_ENCODING_HT) addReplyBulkCBuffer(c,elesds,sdslen(elesds)); else addReplyBulkLongLong(c,intobj); cardinality++; } else { if (encoding == OBJ_ENCODING_INTSET) { elesds = sdsfromlonglong(intobj); setTypeAdd(dstset,elesds); sdsfree(elesds); } else { setTypeAdd(dstset,elesds); } } } } setTypeReleaseIterator(si); if (dstkey) { /* Store the resulting set into the target, if the intersection * is not an empty set. */ int deleted = dbDelete(c->db,dstkey); if (setTypeSize(dstset) > 0) { dbAdd(c->db,dstkey,dstset); addReplyLongLong(c,setTypeSize(dstset)); notifyKeyspaceEvent(NOTIFY_SET,"sinterstore", dstkey,c->db->id); } else { decrRefCount(dstset); addReply(c,shared.czero); if (deleted) notifyKeyspaceEvent(NOTIFY_GENERIC,"del", dstkey,c->db->id); } signalModifiedKey(c->db,dstkey); server.dirty++; } else { setDeferredMultiBulkLength(c,replylen,cardinality); } zfree(sets); }