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);
}