//扩展字典，在检查到需要扩展的时候,这里包含了检测的过程
static int _dictExpandIfNeeded(dict *d)
{
/* Incremental rehashing already in progress. Return. */
//如果正在执行rehash操作，直接返回
if (dictIsRehashing(d)) return DICT_OK;
/* If the hash table is empty expand it to the initial size. */
//第一次添加元素，执行扩展
if (d->ht[0].size == 0) return dictExpand(d, DICT_HT_INITIAL_SIZE);
/* If we reached the 1:1 ratio, and we are allowed to resize the hash
* table (global setting) or we should avoid it but the ratio between
* elements/buckets is over the "safe" threshold, we resize doubling
* the number of buckets. */
//如果设置了resize标记，那么在USED/BUCKET的比率大于1的时候就会执行扩展
//如果没有设置该标志，在该比率超过dict_force_resize_ratio的时候再进行扩展
if (d->ht[0].used >= d->ht[0].size &&
(dict_can_resize ||
d->ht[0].used/d->ht[0].size > dict_force_resize_ratio))
{
//扩展的结果是bucket的数目增大一倍
return dictExpand(d, ((d->ht[0].size > d->ht[0].used) ?
d->ht[0].size : d->ht[0].used)*2);
}
return DICT_OK;
}
/* Expand the hash table if needed */
static int _dictExpandIfNeeded(dict *ht) {
/* If the hash table is empty expand it to the initial size,
* if the table is "full" dobule its size. */
if (ht->size == 0)
return dictExpand(ht, DICT_HT_INITIAL_SIZE);
if (ht->used == ht->size)
return dictExpand(ht, ht->size*2);
return DICT_OK;
}
/* Expand the hash table if needed */
static int _dictExpandIfNeeded(dict *d)
{
/* If the hash table is empty expand it to the intial size,
* if the table is "full" dobule its size. */
if (dictIsRehashing(d)) return DICT_OK;
if (d->ht[0].size == 0)
return dictExpand(d, DICT_HT_INITIAL_SIZE);
if (d->ht[0].used >= d->ht[0].size && dict_can_resize)
return dictExpand(d, ((d->ht[0].size > d->ht[0].used) ?
d->ht[0].size : d->ht[0].used)*2);
return DICT_OK;
}
/* 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");
}
}
/* Resize the table to the minimal size that contains all the elements,
* but with the invariant of a USER/BUCKETS ratio near to <= 1 */
int dictResize(dict *d)
{
int minimal;
if (!dict_can_resize || dictIsRehashing(d)) return DICT_ERR;
minimal = d->ht[0].used;
if (minimal < DICT_HT_INITIAL_SIZE)
minimal = DICT_HT_INITIAL_SIZE;
return dictExpand(d, minimal);
}
ccache *cacheCreate() {
ccache *c = malloc(sizeof(*c));
c->accesslist = listCreate();
c->data = dictCreate(&ccacheType,NULL);
dictExpand(c->data,PRESERVED_CACHE_ENTRIES);
c->outboxOld = safeQueueCreate();
c->outboxNew = safeQueueCreate();
c->inboxNew = safeQueueCreate();
return c;
}
/* Expand the hash table if needed */
static int _dictExpandIfNeeded(dict *d)
{
/* Incremental rehashing already in progress. Return. */
if (dictIsRehashing(d)) return DICT_OK;
/* If the hash table is empty expand it to the initial size. */
if (d->ht[0].size == 0) return dictExpand(d, DICT_HT_INITIAL_SIZE);
/* If we reached the 1:1 ratio, and we are allowed to resize the hash
* table (global setting) or we should avoid it but the ratio between
* elements/buckets is over the "safe" threshold, we resize doubling
* the number of buckets. */
if (d->ht[0].used >= d->ht[0].size &&
(dict_can_resize ||
d->ht[0].used/d->ht[0].size > dict_force_resize_ratio))
{
return dictExpand(d, d->ht[0].used*2);
}
return DICT_OK;
}
/* Resize the table to the minimal size that contains all the elements,
* but with the invariant of a USED/BUCKETS ratio near to <= 1 */
int dictResize(dict *d)
{
int minimal;
//在未设置resize标记和rehash进行中的字典不能进行扩展
if (!dict_can_resize || dictIsRehashing(d)) return DICT_ERR;
//扩展之后的bucket数目将大于当前哈希表中的entry的总数，这样可以使USED/BUCKETS的
//比率小于1，尽量达到O(1)查询的效率
minimal = d->ht[0].used;
if (minimal < DICT_HT_INITIAL_SIZE)
minimal = DICT_HT_INITIAL_SIZE;
return dictExpand(d, minimal);
}
/*************************************************************
* Function : ExpandIfNeeded
* Author : bulldozer.ma
* Date : 2015-11-01
* Input : dict *pHeader
* Output : N/A
* Return : int
* Other : N/A
* Description : ExpandIfNeeded
**************************************************************/
static int ExpandIfNeeded(dict *pHeader)
{
if (NULL == pHeader || dictIsRehashing(pHeader))
{
return DICT_ERROR;
}
unsigned int uiUsed = 0, uiSize = 0;
uiSize = pHeader->ht[0]->size;
uiUsed = pHeader->ht[0]->used;
if (uiUsed > uiSize && 1 <= uiUsed / uiSize)
{
return dictExpand(pHeader, pHeader->ht[1]->size);
}
return DICT_ERROR;
}
void cacheMasterInit() {
pthread_attr_t attr;
master_cache = dictCreate(&objSdsDictType,NULL);
dictExpand(master_cache,PRESERVED_CACHE_ENTRIES);
slave_caches = listCreate();
master_total_mem = 0;
/* Default Http Not Found */
HTTP_NOT_FOUND = objSdsFromSds(sdsnew("HTTP/1.1 404 OK\r\nContent-Length: 9\r\n\r\nNot Found"));
objSdsAddRef(HTTP_NOT_FOUND);
HTTP_NOT_FOUND->state = OBJSDS_OK;
/* status */
statusQuery = sdsnew("/status");
objSds *status_value = objSdsCreate();
status_value->ref = 2; /* ensure that '/status' entry will not be freed */
next_master_refresh_time += time(NULL) + MASTER_STATUS_REFRESH_PERIOD;
dictAdd(master_cache,statusQuery,status_value);
status_value->ptr = _masterGetStatus();
status_value->state = OBJSDS_OK;
/* Initialize mutex and condition variable objects */
/* For portability, explicitly create threads in a joinable state */
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
pthread_create(&master_thread, &attr, _masterWatch, NULL);
bioInit();
/* favicon.ico */
faviconQuery = sdsnew("/favicon.ico");
objSds *favicon_value = objSdsCreate();
favicon_value->ref = 2; /* ensure that the entry will not be freed */
favicon_value->state = OBJSDS_WAITING;
dictAdd(master_cache,faviconQuery,favicon_value);
sds staticFaviconQuery = sdsnew("/static/favicon.ico"); /* static file query */
dictAdd(master_cache,staticFaviconQuery,favicon_value);
bioPushGeneralJob(staticFaviconQuery);
}
