From a5be65f71c927601260f4518236cbc7bc3d87965 Mon Sep 17 00:00:00 2001 From: antirez Date: Thu, 9 Dec 2010 10:21:02 +0100 Subject: [PATCH] COW friendly versions of SPOP and SRANDMEMBER commands, with some change to the set encoding-agnostic API. --- src/intset.c | 2 +- src/intset.h | 2 +- src/redis.h | 2 +- src/t_set.c | 73 ++++++++++++++++++++++++++++++---------------------- 4 files changed, 45 insertions(+), 34 deletions(-) diff --git a/src/intset.c b/src/intset.c index 2f359b7f..bfd3307d 100644 --- a/src/intset.c +++ b/src/intset.c @@ -179,7 +179,7 @@ intset *intsetAdd(intset *is, int64_t value, uint8_t *success) { } /* Delete integer from intset */ -intset *intsetRemove(intset *is, int64_t value, uint8_t *success) { +intset *intsetRemove(intset *is, int64_t value, int *success) { uint8_t valenc = _intsetValueEncoding(value); uint32_t pos; if (success) *success = 0; diff --git a/src/intset.h b/src/intset.h index 25afc18d..10d49d2e 100644 --- a/src/intset.h +++ b/src/intset.h @@ -10,7 +10,7 @@ typedef struct intset { intset *intsetNew(void); intset *intsetAdd(intset *is, int64_t value, uint8_t *success); -intset *intsetRemove(intset *is, int64_t value, uint8_t *success); +intset *intsetRemove(intset *is, int64_t value, int *success); uint8_t intsetFind(intset *is, int64_t value); int64_t intsetRandom(intset *is); uint8_t intsetGet(intset *is, uint32_t pos, int64_t *value); diff --git a/src/redis.h b/src/redis.h index e5db917e..e012db4c 100644 --- a/src/redis.h +++ b/src/redis.h @@ -814,7 +814,7 @@ int setTypeIsMember(robj *subject, robj *value); setTypeIterator *setTypeInitIterator(robj *subject); void setTypeReleaseIterator(setTypeIterator *si); robj *setTypeNext(setTypeIterator *si); -robj *setTypeRandomElement(robj *subject); +int setTypeRandomElement(robj *setobj, robj **objele, long long *llele); unsigned long setTypeSize(robj *subject); void setTypeConvert(robj *subject, int enc); diff --git a/src/t_set.c b/src/t_set.c index 234efc7d..e15952c0 100644 --- a/src/t_set.c +++ b/src/t_set.c @@ -47,17 +47,17 @@ int setTypeAdd(robj *subject, robj *value) { return 0; } -int setTypeRemove(robj *subject, robj *value) { +int setTypeRemove(robj *setobj, robj *value) { long long llval; - if (subject->encoding == REDIS_ENCODING_HT) { - if (dictDelete(subject->ptr,value) == DICT_OK) { - if (htNeedsResize(subject->ptr)) dictResize(subject->ptr); + if (setobj->encoding == REDIS_ENCODING_HT) { + if (dictDelete(setobj->ptr,value) == DICT_OK) { + if (htNeedsResize(setobj->ptr)) dictResize(setobj->ptr); return 1; } - } else if (subject->encoding == REDIS_ENCODING_INTSET) { + } else if (setobj->encoding == REDIS_ENCODING_INTSET) { if (isObjectRepresentableAsLongLong(value,&llval) == REDIS_OK) { - uint8_t success; - subject->ptr = intsetRemove(subject->ptr,llval,&success); + int success; + setobj->ptr = intsetRemove(setobj->ptr,llval,&success); if (success) return 1; } } else { @@ -120,21 +120,29 @@ robj *setTypeNext(setTypeIterator *si) { } -/* Return random element from set. The returned object will always have - * an incremented refcount. */ -robj *setTypeRandomElement(robj *subject) { - robj *ret = NULL; - if (subject->encoding == REDIS_ENCODING_HT) { - dictEntry *de = dictGetRandomKey(subject->ptr); - ret = dictGetEntryKey(de); - incrRefCount(ret); - } else if (subject->encoding == REDIS_ENCODING_INTSET) { - long long llval = intsetRandom(subject->ptr); - ret = createStringObjectFromLongLong(llval); +/* Return random element from a non empty set. + * The returned element can be a long long value if the set is encoded + * as an "intset" blob of integers, or a redis object if the set + * is a regular set. + * + * The caller provides both pointers to be populated with the right + * object. The return value of the function is the object->encoding + * field of the object and is used by the caller to check if the + * long long pointer or the redis object pointere was populated. + * + * When an object is returned (the set was a real set) the ref count + * of the object is not incremented so this function can be considered + * copy-on-write friendly. */ +int setTypeRandomElement(robj *setobj, robj **objele, long long *llele) { + if (setobj->encoding == REDIS_ENCODING_HT) { + dictEntry *de = dictGetRandomKey(setobj->ptr); + *objele = dictGetEntryKey(de); + } else if (setobj->encoding == REDIS_ENCODING_INTSET) { + *llele = intsetRandom(setobj->ptr); } else { redisPanic("Unknown set encoding"); } - return ret; + return setobj->encoding; } unsigned long setTypeSize(robj *subject) { @@ -284,35 +292,38 @@ void scardCommand(redisClient *c) { void spopCommand(redisClient *c) { robj *set, *ele; + long long llele; + int encoding; if ((set = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL || checkType(c,set,REDIS_SET)) return; - ele = setTypeRandomElement(set); - if (ele == NULL) { - addReply(c,shared.nullbulk); + encoding = setTypeRandomElement(set,&ele,&llele); + if (encoding == REDIS_ENCODING_INTSET) { + addReplyBulkLongLong(c,llele); + set->ptr = intsetRemove(set->ptr,llele,NULL); } else { - setTypeRemove(set,ele); addReplyBulk(c,ele); - decrRefCount(ele); - if (setTypeSize(set) == 0) dbDelete(c->db,c->argv[1]); - touchWatchedKey(c->db,c->argv[1]); - server.dirty++; + setTypeRemove(set,ele); } + if (setTypeSize(set) == 0) dbDelete(c->db,c->argv[1]); + touchWatchedKey(c->db,c->argv[1]); + server.dirty++; } void srandmemberCommand(redisClient *c) { robj *set, *ele; + long long llele; + int encoding; if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL || checkType(c,set,REDIS_SET)) return; - ele = setTypeRandomElement(set); - if (ele == NULL) { - addReply(c,shared.nullbulk); + encoding = setTypeRandomElement(set,&ele,&llele); + if (encoding == REDIS_ENCODING_INTSET) { + addReplyBulkLongLong(c,llele); } else { addReplyBulk(c,ele); - decrRefCount(ele); } } -- 2.47.2