public static void AddToDirtyList(PgHdr page)
{
var p = page.Cache;
page.DirtyNext = p.Dirty;
if (page.DirtyNext != null)
{
page.DirtyNext.DirtyPrev = page;
}
p.Dirty = page;
if (p.DirtyTail == null)
{
p.DirtyTail = page;
}
if ((p.Synced == null) && (0 == (page.Flags & PGHDR.NEED_SYNC)))
{
p.Synced = page;
}
}
//private int Fetch(uint pgno, bool createFlag, ref PgHdr ppPage)
//{
// PgHdr page = null;
// int eCreate;
// // If the pluggable cache (sqlite3_pcache*) has not been allocated, allocate it now.
// if ((Cache == null) && createFlag)
// {
// int bytes = PageSize + ExtraSize + sizeof(PgHdr);
// var p = sqlite3GlobalConfig_pcache.Create(bytes, Purgeable);
// if (p == null)
// rc = SQLITE_NOMEM;
// sqlite3GlobalConfig_pcache.Cachesize(p, Max);
// Cache = p;
// }
// eCreate = createFlag * (1 + (!Purgeable || (Dirty == null)));
// if (Cache != null)
// page = sqlite3GlobalConfig_pcache.Fetch(Cache, pgno, eCreate);
// if (!page && eCreate == 1)
// {
// PgHdr pPg;
// // Find a dirty page to write-out and recycle. First try to find a page that does not require a journal-sync (one with PGHDR_NEED_SYNC
// // cleared), but if that is not possible settle for any other unreferenced dirty page.
// for (pPg = Synced; (pPg != null) && ((pPg.Ref != 0) || ((pPg.Flags & PGHDR.NEED_SYNC) != 0)); pPg = pPg.DirtyPrev) { }
// Synced = pPg;
// if (pPg == null)
// for (pPg = DirtyTail; (pPg != null) && (pPg.Ref != 0); pPg = pPg.DirtyPrev) { }
// if (pPg != null)
// {
// int rc;
// rc = Stress(StressArg, pPg);
// if (rc != SQLITE_OK && rc != SQLITE_BUSY)
// return rc;
// }
// page = sqlite3GlobalConfig_pcache.xFetch(pCache->pCache, pgno, 2);
// }
// if (page)
// {
// if (!page->pData)
// {
// memset(page, 0, sizeof(PgHdr));
// page->pData = (void*)&page[1];
// page->pExtra = (void*)&((char*)page->pData)[pCache->szPage];
// memset(page->pExtra, 0, pCache->szExtra);
// page->pCache = pCache;
// page->pgno = pgno;
// }
// if (0 == page->nRef)
// pCache->nRef++;
// page->nRef++;
// if (pgno == 1)
// pCache->pPage1 = page;
// }
// ppPage = page;
// return ((page == 0) && eCreate ? SQLITE_NOMEM : SQLITE_OK);
//}
private static void Release(PgHdr p)
{
Contract.Assert(p.Ref > 0);
p.Ref--;
if (p.Ref == 0)
{
var cache = p.Cache;
cache.Ref--;
if ((p.Flags & PGHDR.DIRTY) == 0)
{
Unpin(p);
}
else
{
// Move the page to the head of the dirty list.
RemoveFromDirtyList(p);
AddToDirtyList(p);
}
}
}
private static PgHdr SortDirtyList(PgHdr pIn)
{
var a = new PgHdr[N_SORT_BUCKET];
PgHdr p;
//memset(a, 0, sizeof(a));
while (pIn != null)
{
p = pIn;
pIn = p.Dirty;
p.Dirty = null;
int i;
for (i = 0; i < N_SORT_BUCKET - 1; i++)
{
if (a[i] == null)
{
a[i] = p;
break;
}
else
{
p = MergeDirtyList(a[i], p);
a[i] = null;
}
}
if (i == N_SORT_BUCKET - 1)
{
// To get here, there need to be 2^(N_SORT_BUCKET) elements in the input list. But that is impossible.
a[i] = MergeDirtyList(a[i], p);
}
}
p = a[0];
for (int i = 1; i < N_SORT_BUCKET; i++)
{
p = MergeDirtyList(p, a[i]);
}
return(p);
}
private static int PageRefcount(PgHdr p)
{
return(p.Ref);
}
private static void Ref2(PgHdr p)
{
p.Ref++;
}
