/* Convert the set to specified encoding. The resulting dict (when converting
* to a hashtable) is presized to hold the number of elements in the original
* set. */
void setTypeConvert(robj *setobj, int enc) {
setTypeIterator *si;
redisAssert(setobj->type == REDIS_SET &&
setobj->encoding == REDIS_ENCODING_INTSET);
if (enc == REDIS_ENCODING_HT) {
int64_t intele;
dict *d = dictCreate(&setDictType,NULL);
robj *element;
/* Presize the dict to avoid rehashing */
dictExpand(d,intsetLen(setobj->ptr));
/* To add the elements we extract integers and create redis objects */
si = setTypeInitIterator(setobj);
while (setTypeNext(si,NULL,&intele) != -1) {
element = createStringObjectFromLongLong(intele);
redisAssert(dictAdd(d,element,NULL) == DICT_OK);
}
setTypeReleaseIterator(si);
setobj->encoding = REDIS_ENCODING_HT;
zfree(setobj->ptr);
setobj->ptr = d;
} else {
redisPanic("Unsupported set conversion");
}
}
static void* loadSetIntsetObject(unsigned char* sl, unsigned int *rlen) {
int64_t intele;
unsigned int i = 0, len;
setTypeIterator *si;
len = ((intset*)sl)->length;
*rlen = len;
si = setTypeInitIterator(sl);
sds *results = zmalloc(len * sizeof(sds));
while (setTypeNext(si,&intele) != -1) {
results[i++] = sdsfromlonglong(intele);
}
setTypeReleaseIterator(si);
return results;
}
/* The not copy on write friendly version but easy to use version
* of setTypeNext() is setTypeNextObject(), returning new SDS
* strings. So if you don't retain a pointer to this object you should call
* sdsfree() against it.
*
* This function is the way to go for write operations where COW is not
* an issue. */
sds setTypeNextObject(setTypeIterator *si) {
int64_t intele;
sds sdsele;
int encoding;
encoding = setTypeNext(si,&sdsele,&intele);
switch(encoding) {
case -1: return NULL;
case OBJ_ENCODING_INTSET:
return sdsfromlonglong(intele);
case OBJ_ENCODING_HT:
return sdsdup(sdsele);
default:
serverPanic("Unsupported encoding");
}
return NULL; /* just to suppress warnings */
}
/* The not copy on write friendly version but easy to use version
* of setTypeNext() is setTypeNextObject(), returning new objects
* or incrementing the ref count of returned objects. So if you don't
* retain a pointer to this object you should call decrRefCount() against it.
*
* This function is the way to go for write operations where COW is not
* an issue as the result will be anyway of incrementing the ref count. */
robj *setTypeNextObject(setTypeIterator *si) {
int64_t intele;
robj *objele;
int encoding;
encoding = setTypeNext(si,&objele,&intele);
switch(encoding) {
case -1: return NULL;
case REDIS_ENCODING_INTSET:
return createStringObjectFromLongLong(intele);
case REDIS_ENCODING_HT:
incrRefCount(objele);
return objele;
default:
redisPanic("Unsupported encoding");
}
return NULL; /* just to suppress warnings */
}
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);
}
void srandmemberWithCountCommand(redisClient *c) {
long l;
unsigned long count, size;
int uniq = 1;
robj *set, *ele;
int64_t llele;
int encoding;
dict *d;
if (getLongFromObjectOrReply(c,c->argv[2],&l,NULL) != REDIS_OK) return;
if (l >= 0) {
count = (unsigned) l;
} else {
/* A negative count means: return the same elements multiple times
* (i.e. don't remove the extracted element after every extraction). */
count = -l;
uniq = 0;
}
if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.emptymultibulk))
== NULL || checkType(c,set,REDIS_SET)) return;
size = setTypeSize(set);
/* If count is zero, serve it ASAP to avoid special cases later. */
if (count == 0) {
addReply(c,shared.emptymultibulk);
return;
}
/* CASE 1: The count was negative, so the extraction method is just:
* "return N random elements" sampling the whole set every time.
* This case is trivial and can be served without auxiliary data
* structures. */
if (!uniq) {
addReplyMultiBulkLen(c,count);
while(count--) {
encoding = setTypeRandomElement(set,&ele,&llele);
if (encoding == REDIS_ENCODING_INTSET) {
addReplyBulkLongLong(c,llele);
} else {
addReplyBulk(c,ele);
}
}
return;
}
/* CASE 2:
* The number of requested elements is greater than the number of
* elements inside the set: simply return the whole set. */
if (count >= size) {
sunionDiffGenericCommand(c,c->argv+1,1,NULL,REDIS_OP_UNION);
return;
}
/* For CASE 3 and CASE 4 we need an auxiliary dictionary. */
d = dictCreate(&setDictType,NULL);
/* CASE 3:
* The number of elements inside the set is not greater than
* SRANDMEMBER_SUB_STRATEGY_MUL times the number of requested elements.
* In this case we create a set from scratch with all the elements, and
* subtract random elements to reach the requested number of elements.
*
* This is done because if the number of requsted elements is just
* a bit less than the number of elements in the set, the natural approach
* used into CASE 3 is highly inefficient. */
if (count*SRANDMEMBER_SUB_STRATEGY_MUL > size) {
setTypeIterator *si;
/* Add all the elements into the temporary dictionary. */
si = setTypeInitIterator(set);
while((encoding = setTypeNext(si,&ele,&llele)) != -1) {
int retval = DICT_ERR;
if (encoding == REDIS_ENCODING_INTSET) {
retval = dictAdd(d,createStringObjectFromLongLong(llele),NULL);
} else if (ele->encoding == REDIS_ENCODING_RAW) {
retval = dictAdd(d,dupStringObject(ele),NULL);
} else if (ele->encoding == REDIS_ENCODING_INT) {
retval = dictAdd(d,
createStringObjectFromLongLong((long)ele->ptr),NULL);
}
redisAssert(retval == DICT_OK);
}
setTypeReleaseIterator(si);
redisAssert(dictSize(d) == size);
/* Remove random elements to reach the right count. */
while(size > count) {
dictEntry *de;
de = dictGetRandomKey(d);
dictDelete(d,dictGetKey(de));
size--;
}
}
/* CASE 4: We have a big set compared to the requested number of elements.
* In this case we can simply get random elements from the set and add
* to the temporary set, trying to eventually get enough unique elements
* to reach the specified count. */
else {
unsigned long added = 0;
while(added < count) {
encoding = setTypeRandomElement(set,&ele,&llele);
if (encoding == REDIS_ENCODING_INTSET) {
ele = createStringObjectFromLongLong(llele);
} else if (ele->encoding == REDIS_ENCODING_RAW) {
ele = dupStringObject(ele);
} else if (ele->encoding == REDIS_ENCODING_INT) {
ele = createStringObjectFromLongLong((long)ele->ptr);
}
/* Try to add the object to the dictionary. If it already exists
* free it, otherwise increment the number of objects we have
* in the result dictionary. */
if (dictAdd(d,ele,NULL) == DICT_OK)
added++;
else
decrRefCount(ele);
}
}
/* CASE 3 & 4: send the result to the user. */
{
dictIterator *di;
dictEntry *de;
addReplyMultiBulkLen(c,count);
di = dictGetIterator(d);
while((de = dictNext(di)) != NULL)
addReplyBulk(c,dictGetKey(de));
dictReleaseIterator(di);
dictRelease(d);
}
}
void spopWithCountCommand(redisClient *c) {
long l;
unsigned long count, size;
robj *set;
/* Get the count argument */
if (getLongFromObjectOrReply(c,c->argv[2],&l,NULL) != REDIS_OK) return;
if (l >= 0) {
count = (unsigned) l;
} else {
addReply(c,shared.outofrangeerr);
return;
}
/* Make sure a key with the name inputted exists, and that it's type is
* indeed a set. Otherwise, return nil */
if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.emptymultibulk))
== NULL || checkType(c,set,REDIS_SET)) return;
/* If count is zero, serve an empty multibulk ASAP to avoid special
* cases later. */
if (count == 0) {
addReply(c,shared.emptymultibulk);
return;
}
size = setTypeSize(set);
/* Generate an SPOP keyspace notification */
notifyKeyspaceEvent(REDIS_NOTIFY_SET,"spop",c->argv[1],c->db->id);
server.dirty += count;
/* CASE 1:
* The number of requested elements is greater than or equal to
* the number of elements inside the set: simply return the whole set. */
if (count >= size) {
/* We just return the entire set */
sunionDiffGenericCommand(c,c->argv+1,1,NULL,REDIS_OP_UNION);
/* Delete the set as it is now empty */
dbDelete(c->db,c->argv[1]);
notifyKeyspaceEvent(REDIS_NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
/* Propagate this command as an DEL operation */
rewriteClientCommandVector(c,2,shared.del,c->argv[1]);
signalModifiedKey(c->db,c->argv[1]);
server.dirty++;
return;
}
/* Case 2 and 3 require to replicate SPOP as a set of SERM commands.
* Prepare our replication argument vector. Also send the array length
* which is common to both the code paths. */
robj *propargv[3];
propargv[0] = createStringObject("SREM",4);
propargv[1] = c->argv[1];
addReplyMultiBulkLen(c,count);
/* Common iteration vars. */
robj *objele;
int encoding;
int64_t llele;
unsigned long remaining = size-count; /* Elements left after SPOP. */
/* If we are here, the number of requested elements is less than the
* number of elements inside the set. Also we are sure that count < size.
* Use two different strategies.
*
* CASE 2: The number of elements to return is small compared to the
* set size. We can just extract random elements and return them to
* the set. */
if (remaining*SPOP_MOVE_STRATEGY_MUL > count) {
while(count--) {
encoding = setTypeRandomElement(set,&objele,&llele);
if (encoding == REDIS_ENCODING_INTSET) {
objele = createStringObjectFromLongLong(llele);
} else {
incrRefCount(objele);
}
/* Return the element to the client and remove from the set. */
addReplyBulk(c,objele);
setTypeRemove(set,objele);
/* Replicate/AOF this command as an SREM operation */
propargv[2] = objele;
alsoPropagate(server.sremCommand,c->db->id,propargv,3,
REDIS_PROPAGATE_AOF|REDIS_PROPAGATE_REPL);
decrRefCount(objele);
}
} else {
/* CASE 3: The number of elements to return is very big, approaching
* the size of the set itself. After some time extracting random elements
* from such a set becomes computationally expensive, so we use
* a different strategy, we extract random elements that we don't
* want to return (the elements that will remain part of the set),
* creating a new set as we do this (that will be stored as the original
* set). Then we return the elements left in the original set and
* release it. */
robj *newset = NULL;
/* Create a new set with just the remaining elements. */
while(remaining--) {
encoding = setTypeRandomElement(set,&objele,&llele);
if (encoding == REDIS_ENCODING_INTSET) {
objele = createStringObjectFromLongLong(llele);
} else {
incrRefCount(objele);
}
if (!newset) newset = setTypeCreate(objele);
setTypeAdd(newset,objele);
setTypeRemove(set,objele);
decrRefCount(objele);
}
/* Assign the new set as the key value. */
incrRefCount(set); /* Protect the old set value. */
dbOverwrite(c->db,c->argv[1],newset);
/* Tranfer the old set to the client and release it. */
setTypeIterator *si;
si = setTypeInitIterator(set);
while((encoding = setTypeNext(si,&objele,&llele)) != -1) {
if (encoding == REDIS_ENCODING_INTSET) {
objele = createStringObjectFromLongLong(llele);
} else {
incrRefCount(objele);
}
addReplyBulk(c,objele);
/* Replicate/AOF this command as an SREM operation */
propargv[2] = objele;
alsoPropagate(server.sremCommand,c->db->id,propargv,3,
REDIS_PROPAGATE_AOF|REDIS_PROPAGATE_REPL);
decrRefCount(objele);
}
setTypeReleaseIterator(si);
decrRefCount(set);
}
/* Don't propagate the command itself even if we incremented the
* dirty counter. We don't want to propagate an SPOP command since
* we propagated the command as a set of SREMs operations using
* the alsoPropagate() API. */
decrRefCount(propargv[0]);
preventCommandPropagation(c);
}
/* The SORT command is the most complex command in Redis. Warning: this code
* is optimized for speed and a bit less for readability */
void sortCommand(redisClient *c) {
list *operations;
unsigned int outputlen = 0;
int desc = 0, alpha = 0;
int limit_start = 0, limit_count = -1, start, end;
int j, dontsort = 0, vectorlen;
int getop = 0; /* GET operation counter */
robj *sortval, *sortby = NULL, *storekey = NULL;
redisSortObject *vector; /* Resulting vector to sort */
/* Lookup the key to sort. It must be of the right types */
sortval = lookupKeyRead(c->db,c->argv[1]);
if (sortval == NULL) {
addReply(c,shared.emptymultibulk);
return;
}
if (sortval->type != REDIS_SET && sortval->type != REDIS_LIST &&
sortval->type != REDIS_ZSET)
{
addReply(c,shared.wrongtypeerr);
return;
}
/* Create a list of operations to perform for every sorted element.
* Operations can be GET/DEL/INCR/DECR */
operations = listCreate();
listSetFreeMethod(operations,zfree);
j = 2;
/* Now we need to protect sortval incrementing its count, in the future
* SORT may have options able to overwrite/delete keys during the sorting
* and the sorted key itself may get destroied */
incrRefCount(sortval);
/* The SORT command has an SQL-alike syntax, parse it */
while(j < c->argc) {
int leftargs = c->argc-j-1;
if (!strcasecmp(c->argv[j]->ptr,"asc")) {
desc = 0;
} else if (!strcasecmp(c->argv[j]->ptr,"desc")) {
desc = 1;
} else if (!strcasecmp(c->argv[j]->ptr,"alpha")) {
alpha = 1;
} else if (!strcasecmp(c->argv[j]->ptr,"limit") && leftargs >= 2) {
limit_start = atoi(c->argv[j+1]->ptr);
limit_count = atoi(c->argv[j+2]->ptr);
j+=2;
} else if (!strcasecmp(c->argv[j]->ptr,"store") && leftargs >= 1) {
storekey = c->argv[j+1];
j++;
} else if (!strcasecmp(c->argv[j]->ptr,"by") && leftargs >= 1) {
sortby = c->argv[j+1];
/* If the BY pattern does not contain '*', i.e. it is constant,
* we don't need to sort nor to lookup the weight keys. */
if (strchr(c->argv[j+1]->ptr,'*') == NULL) dontsort = 1;
j++;
} else if (!strcasecmp(c->argv[j]->ptr,"get") && leftargs >= 1) {
listAddNodeTail(operations,createSortOperation(
REDIS_SORT_GET,c->argv[j+1]));
getop++;
j++;
} else {
decrRefCount(sortval);
listRelease(operations);
addReply(c,shared.syntaxerr);
return;
}
j++;
}
/* Load the sorting vector with all the objects to sort */
switch(sortval->type) {
case REDIS_LIST: vectorlen = listTypeLength(sortval); break;
case REDIS_SET: vectorlen = setTypeSize(sortval); break;
case REDIS_ZSET: vectorlen = dictSize(((zset*)sortval->ptr)->dict); break;
default: vectorlen = 0; redisPanic("Bad SORT type"); /* Avoid GCC warning */
}
vector = zmalloc(sizeof(redisSortObject)*vectorlen);
j = 0;
if (sortval->type == REDIS_LIST) {
listTypeIterator *li = listTypeInitIterator(sortval,0,REDIS_TAIL);
listTypeEntry entry;
while(listTypeNext(li,&entry)) {
vector[j].obj = listTypeGet(&entry);
vector[j].u.score = 0;
vector[j].u.cmpobj = NULL;
j++;
}
listTypeReleaseIterator(li);
} else if (sortval->type == REDIS_SET) {
setTypeIterator *si = setTypeInitIterator(sortval);
robj *ele;
while((ele = setTypeNext(si)) != NULL) {
vector[j].obj = ele;
vector[j].u.score = 0;
vector[j].u.cmpobj = NULL;
j++;
}
setTypeReleaseIterator(si);
} else if (sortval->type == REDIS_ZSET) {
dict *set = ((zset*)sortval->ptr)->dict;
dictIterator *di;
dictEntry *setele;
di = dictGetIterator(set);
while((setele = dictNext(di)) != NULL) {
vector[j].obj = dictGetEntryKey(setele);
vector[j].u.score = 0;
vector[j].u.cmpobj = NULL;
j++;
}
dictReleaseIterator(di);
} else {
redisPanic("Unknown type");
}
redisAssert(j == vectorlen);
/* Now it's time to load the right scores in the sorting vector */
if (dontsort == 0) {
for (j = 0; j < vectorlen; j++) {
robj *byval;
if (sortby) {
/* lookup value to sort by */
byval = lookupKeyByPattern(c->db,sortby,vector[j].obj);
if (!byval) continue;
} else {
/* use object itself to sort by */
byval = vector[j].obj;
}
if (alpha) {
if (sortby) vector[j].u.cmpobj = getDecodedObject(byval);
} else {
if (byval->encoding == REDIS_ENCODING_RAW) {
vector[j].u.score = strtod(byval->ptr,NULL);
} else if (byval->encoding == REDIS_ENCODING_INT) {
/* Don't need to decode the object if it's
* integer-encoded (the only encoding supported) so
* far. We can just cast it */
vector[j].u.score = (long)byval->ptr;
} else {
redisAssert(1 != 1);
}
}
/* when the object was retrieved using lookupKeyByPattern,
* its refcount needs to be decreased. */
if (sortby) {
decrRefCount(byval);
}
}
}
/* We are ready to sort the vector... perform a bit of sanity check
* on the LIMIT option too. We'll use a partial version of quicksort. */
start = (limit_start < 0) ? 0 : limit_start;
end = (limit_count < 0) ? vectorlen-1 : start+limit_count-1;
if (start >= vectorlen) {
start = vectorlen-1;
end = vectorlen-2;
}
if (end >= vectorlen) end = vectorlen-1;
if (dontsort == 0) {
server.sort_desc = desc;
server.sort_alpha = alpha;
server.sort_bypattern = sortby ? 1 : 0;
if (sortby && (start != 0 || end != vectorlen-1))
pqsort(vector,vectorlen,sizeof(redisSortObject),sortCompare, start,end);
else
qsort(vector,vectorlen,sizeof(redisSortObject),sortCompare);
}
/* Send command output to the output buffer, performing the specified
* GET/DEL/INCR/DECR operations if any. */
outputlen = getop ? getop*(end-start+1) : end-start+1;
if (storekey == NULL) {
/* STORE option not specified, sent the sorting result to client */
addReplyMultiBulkLen(c,outputlen);
for (j = start; j <= end; j++) {
listNode *ln;
listIter li;
if (!getop) addReplyBulk(c,vector[j].obj);
listRewind(operations,&li);
while((ln = listNext(&li))) {
redisSortOperation *sop = ln->value;
robj *val = lookupKeyByPattern(c->db,sop->pattern,
vector[j].obj);
if (sop->type == REDIS_SORT_GET) {
if (!val) {
addReply(c,shared.nullbulk);
} else {
addReplyBulk(c,val);
decrRefCount(val);
}
} else {
redisAssert(sop->type == REDIS_SORT_GET); /* always fails */
}
}
}
} else {
robj *sobj = createZiplistObject();
/* STORE option specified, set the sorting result as a List object */
for (j = start; j <= end; j++) {
listNode *ln;
listIter li;
if (!getop) {
listTypePush(sobj,vector[j].obj,REDIS_TAIL);
} else {
listRewind(operations,&li);
while((ln = listNext(&li))) {
redisSortOperation *sop = ln->value;
robj *val = lookupKeyByPattern(c->db,sop->pattern,
vector[j].obj);
if (sop->type == REDIS_SORT_GET) {
if (!val) val = createStringObject("",0);
/* listTypePush does an incrRefCount, so we should take care
* care of the incremented refcount caused by either
* lookupKeyByPattern or createStringObject("",0) */
listTypePush(sobj,val,REDIS_TAIL);
decrRefCount(val);
} else {
/* always fails */
redisAssert(sop->type == REDIS_SORT_GET);
}
}
}
}
dbReplace(c->db,storekey,sobj);
/* Note: we add 1 because the DB is dirty anyway since even if the
* SORT result is empty a new key is set and maybe the old content
* replaced. */
server.dirty += 1+outputlen;
touchWatchedKey(c->db,storekey);
addReplyLongLong(c,outputlen);
}
/* Cleanup */
if (sortval->type == REDIS_LIST || sortval->type == REDIS_SET)
for (j = 0; j < vectorlen; j++)
decrRefCount(vector[j].obj);
decrRefCount(sortval);
listRelease(operations);
for (j = 0; j < vectorlen; j++) {
if (alpha && vector[j].u.cmpobj)
decrRefCount(vector[j].u.cmpobj);
}
zfree(vector);
}
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);
}