Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

499 lines (452 sloc) 18.343 kb
#include "redis.h"
#include "pqsort.h" /* Partial qsort for SORT+LIMIT */
#include <math.h> /* isnan() */
zskiplistNode* zslGetElementByRank(zskiplist *zsl, unsigned long rank);
redisSortOperation *createSortOperation(int type, robj *pattern) {
redisSortOperation *so = zmalloc(sizeof(*so));
so->type = type;
so->pattern = pattern;
return so;
}
/* Return the value associated to the key with a name obtained using
* the following rules:
*
* 1) The first occurence of '*' in 'pattern' is substituted with 'subst'.
*
* 2) If 'pattern' matches the "->" string, everything on the left of
* the arrow is treated as the name of an hash field, and the part on the
* left as the key name containing an hash. The value of the specified
* field is returned.
*
* 3) If 'pattern' equals "#", the function simply returns 'subst' itself so
* that the SORT command can be used like: SORT key GET # to retrieve
* the Set/List elements directly.
*
* The returned object will always have its refcount increased by 1
* when it is non-NULL. */
robj *lookupKeyByPattern(redisDb *db, robj *pattern, robj *subst) {
char *p, *f, *k;
sds spat, ssub;
robj *keyobj, *fieldobj = NULL, *o;
int prefixlen, sublen, postfixlen, fieldlen;
/* If the pattern is "#" return the substitution object itself in order
* to implement the "SORT ... GET #" feature. */
spat = pattern->ptr;
if (spat[0] == '#' && spat[1] == '\0') {
incrRefCount(subst);
return subst;
}
/* The substitution object may be specially encoded. If so we create
* a decoded object on the fly. Otherwise getDecodedObject will just
* increment the ref count, that we'll decrement later. */
subst = getDecodedObject(subst);
ssub = subst->ptr;
/* If we can't find '*' in the pattern we return NULL as to GET a
* fixed key does not make sense. */
p = strchr(spat,'*');
if (!p) {
decrRefCount(subst);
return NULL;
}
/* Find out if we're dealing with a hash dereference. */
if ((f = strstr(p+1, "->")) != NULL && *(f+2) != '\0') {
fieldlen = sdslen(spat)-(f-spat)-2;
fieldobj = createStringObject(f+2,fieldlen);
} else {
fieldlen = 0;
}
/* Perform the '*' substitution. */
prefixlen = p-spat;
sublen = sdslen(ssub);
postfixlen = sdslen(spat)-(prefixlen+1)-(fieldlen ? fieldlen+2 : 0);
keyobj = createStringObject(NULL,prefixlen+sublen+postfixlen);
k = keyobj->ptr;
memcpy(k,spat,prefixlen);
memcpy(k+prefixlen,ssub,sublen);
memcpy(k+prefixlen+sublen,p+1,postfixlen);
decrRefCount(subst); /* Incremented by decodeObject() */
/* Lookup substituted key */
o = lookupKeyRead(db,keyobj);
if (o == NULL) goto noobj;
if (fieldobj) {
if (o->type != REDIS_HASH) goto noobj;
/* Retrieve value from hash by the field name. This operation
* already increases the refcount of the returned object. */
o = hashTypeGetObject(o, fieldobj);
} else {
if (o->type != REDIS_STRING) goto noobj;
/* Every object that this function returns needs to have its refcount
* increased. sortCommand decreases it again. */
incrRefCount(o);
}
decrRefCount(keyobj);
if (fieldobj) decrRefCount(fieldobj);
return o;
noobj:
decrRefCount(keyobj);
if (fieldlen) decrRefCount(fieldobj);
return NULL;
}
/* sortCompare() is used by qsort in sortCommand(). Given that qsort_r with
* the additional parameter is not standard but a BSD-specific we have to
* pass sorting parameters via the global 'server' structure */
int sortCompare(const void *s1, const void *s2) {
const redisSortObject *so1 = s1, *so2 = s2;
int cmp;
if (!server.sort_alpha) {
/* Numeric sorting. Here it's trivial as we precomputed scores */
if (so1->u.score > so2->u.score) {
cmp = 1;
} else if (so1->u.score < so2->u.score) {
cmp = -1;
} else {
/* Objects have the same score, but we don't want the comparison
* to be undefined, so we compare objects lexicographycally.
* This way the result of SORT is deterministic. */
cmp = compareStringObjects(so1->obj,so2->obj);
}
} else {
/* Alphanumeric sorting */
if (server.sort_bypattern) {
if (!so1->u.cmpobj || !so2->u.cmpobj) {
/* At least one compare object is NULL */
if (so1->u.cmpobj == so2->u.cmpobj)
cmp = 0;
else if (so1->u.cmpobj == NULL)
cmp = -1;
else
cmp = 1;
} else {
/* We have both the objects, use strcoll */
cmp = strcoll(so1->u.cmpobj->ptr,so2->u.cmpobj->ptr);
}
} else {
/* Compare elements directly. */
cmp = compareStringObjects(so1->obj,so2->obj);
}
}
return server.sort_desc ? -cmp : cmp;
}
/* 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;
long limit_start = 0, limit_count = -1, start, end;
int j, dontsort = 0, vectorlen;
int getop = 0; /* GET operation counter */
int int_convertion_error = 0;
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 && 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; /* options start at argv[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 */
if (sortval)
incrRefCount(sortval);
else
sortval = createListObject();
/* 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) {
if ((getLongFromObjectOrReply(c, c->argv[j+1], &limit_start, NULL) != REDIS_OK) ||
(getLongFromObjectOrReply(c, c->argv[j+2], &limit_count, NULL) != REDIS_OK)) return;
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++;
}
/* For the STORE option, or when SORT is called from a Lua script,
* we want to force a specific ordering even when no explicit ordering
* was asked (SORT BY nosort). This guarantees that replication / AOF
* is deterministic.
*
* However in the case 'dontsort' is true, but the type to sort is a
* sorted set, we don't need to do anything as ordering is guaranteed
* in this special case. */
if ((storekey || c->flags & REDIS_LUA_CLIENT) &&
(dontsort && sortval->type != REDIS_ZSET))
{
/* Force ALPHA sorting */
dontsort = 0;
alpha = 1;
sortby = NULL;
}
/* Destructively convert encoded sorted sets for SORT. */
if (sortval->type == REDIS_ZSET)
zsetConvert(sortval, REDIS_ENCODING_SKIPLIST);
/* Objtain the length of the object 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 */
}
/* Perform LIMIT start,count sanity checking. */
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;
/* Optimization:
*
* 1) if the object to sort is a sorted set.
* 2) There is nothing to sort as dontsort is true (BY <constant string>).
* 3) We have a LIMIT option that actually reduces the number of elements
* to fetch.
*
* In this case to load all the objects in the vector is a huge waste of
* resources. We just allocate a vector that is big enough for the selected
* range length, and make sure to load just this part in the vector. */
if (sortval->type == REDIS_ZSET &&
dontsort &&
(start != 0 || end != vectorlen-1))
{
vectorlen = end-start+1;
}
/* Load the sorting vector with all the objects to sort */
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 = setTypeNextObject(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 && dontsort) {
/* Special handling for a sorted set, if 'dontsort' is true.
* This makes sure we return elements in the sorted set original
* ordering, accordingly to DESC / ASC options.
*
* Note that in this case we also handle LIMIT here in a direct
* way, just getting the required range, as an optimization. */
zset *zs = sortval->ptr;
zskiplist *zsl = zs->zsl;
zskiplistNode *ln;
robj *ele;
int rangelen = vectorlen;
/* Check if starting point is trivial, before doing log(N) lookup. */
if (desc) {
long zsetlen = dictSize(((zset*)sortval->ptr)->dict);
ln = zsl->tail;
if (start > 0)
ln = zslGetElementByRank(zsl,zsetlen-start);
} else {
ln = zsl->header->level[0].forward;
if (start > 0)
ln = zslGetElementByRank(zsl,start+1);
}
while(rangelen--) {
redisAssertWithInfo(c,sortval,ln != NULL);
ele = ln->obj;
vector[j].obj = ele;
vector[j].u.score = 0;
vector[j].u.cmpobj = NULL;
j++;
ln = desc ? ln->backward : ln->level[0].forward;
}
/* The code producing the output does not know that in the case of
* sorted set, 'dontsort', and LIMIT, we are able to get just the
* range, already sorted, so we need to adjust "start" and "end"
* to make sure start is set to 0. */
end -= start;
start = 0;
} 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 = dictGetKey(setele);
vector[j].u.score = 0;
vector[j].u.cmpobj = NULL;
j++;
}
dictReleaseIterator(di);
} else {
redisPanic("Unknown type");
}
redisAssertWithInfo(c,sortval,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) {
char *eptr;
vector[j].u.score = strtod(byval->ptr,&eptr);
if (eptr[0] != '\0' || errno == ERANGE ||
isnan(vector[j].u.score))
{
int_convertion_error = 1;
}
} 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 {
redisAssertWithInfo(c,sortval,1 != 1);
}
}
/* when the object was retrieved using lookupKeyByPattern,
* its refcount needs to be decreased. */
if (sortby) {
decrRefCount(byval);
}
}
}
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 (int_convertion_error) {
addReplyError(c,"One or more scores can't be converted into double");
} else 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 {
/* Always fails */
redisAssertWithInfo(c,sortval,sop->type == REDIS_SORT_GET);
}
}
}
} 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 */
redisAssertWithInfo(c,sortval,sop->type == REDIS_SORT_GET);
}
}
}
}
if (outputlen) {
setKey(c->db,storekey,sobj);
server.dirty += outputlen;
} else if (dbDelete(c->db,storekey)) {
signalModifiedKey(c->db,storekey);
server.dirty++;
}
decrRefCount(sobj);
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);
}
Jump to Line
Something went wrong with that request. Please try again.