/*
** Implementation of the sqlite3_pcache.xRekey method.
*/
static void pcache1Rekey(
sqlite3_pcache *p,
void *pPg,
unsigned int iOld,
unsigned int iNew
){
PCache1 *pCache = (PCache1 *)p;
PgHdr1 *pPage = PAGE_TO_PGHDR1(pPg);
PgHdr1 **pp;
unsigned int h;
assert( pPage->iKey==iOld );
pcache1EnterMutex();
h = iOld%pCache->nHash;
pp = &pCache->apHash[h];
while( (*pp)!=pPage ){
pp = &(*pp)->pNext;
}
*pp = pPage->pNext;
h = iNew%pCache->nHash;
pPage->iKey = iNew;
pPage->pNext = pCache->apHash[h];
pCache->apHash[h] = pPage;
if( iNew>pCache->iMaxKey ){
pCache->iMaxKey = iNew;
}
pcache1LeaveMutex();
}
/*
** Implementation of the sqlite3_pcache.xUnpin method.
**
** Mark a page as unpinned (eligible for asynchronous recycling).
*/
static void pcache1Unpin(sqlite3_pcache *p, void *pPg, int reuseUnlikely){
PCache1 *pCache = (PCache1 *)p;
PgHdr1 *pPage = PAGE_TO_PGHDR1(pPg);
pcache1EnterMutex();
/* It is an error to call this function if the page is already
** part of the global LRU list.
*/
assert( pPage->pLruPrev==0 && pPage->pLruNext==0 );
assert( pcache1.pLruHead!=pPage && pcache1.pLruTail!=pPage );
if( reuseUnlikely || pcache1.nCurrentPage>pcache1.nMaxPage ){
pcache1RemoveFromHash(pPage);
pcache1FreePage(pPage);
}else{
/* Add the page to the global LRU list. Normally, the page is added to
** the head of the list (last page to be recycled). However, if the
** reuseUnlikely flag passed to this function is true, the page is added
** to the tail of the list (first page to be recycled).
*/
if( pcache1.pLruHead ){
pcache1.pLruHead->pLruPrev = pPage;
pPage->pLruNext = pcache1.pLruHead;
pcache1.pLruHead = pPage;
}else{
pcache1.pLruTail = pPage;
pcache1.pLruHead = pPage;
}
pCache->nRecyclable++;
}
pcache1LeaveMutex();
}
/*
** Allocate a new page object initially associated with cache pCache.
*/
static PgHdr1 *pcache1AllocPage(PCache1 *pCache){
int nByte = sizeof(PgHdr1) + pCache->szPage;
void *pPg = pcache1Alloc(nByte);
PgHdr1 *p;
if( pPg ){
p = PAGE_TO_PGHDR1(pCache, pPg);
if( pCache->bPurgeable ){
pcache1.nCurrentPage++;
}
}else{
p = 0;
}
return p;
}
