internal static void copyNodeContent(MemPage pFrom, MemPage pTo, ref RC pRC)
{
if (pRC != RC.OK)
{
return;
}
var pBt = pFrom.Shared;
var aFrom = pFrom.Data;
var aTo = pTo.Data;
var iFromHdr = pFrom.HeaderOffset;
var iToHdr = (pTo.ID == 1 ? 100 : 0);
Debug.Assert(pFrom.HasInit);
Debug.Assert(pFrom.FreeBytes >= iToHdr);
Debug.Assert(ConvertEx.Get2(aFrom, iFromHdr + 5) <= (int)pBt.UsableSize);
// Copy the b-tree node content from page pFrom to page pTo.
var iData = (int)ConvertEx.Get2(aFrom, iFromHdr + 5);
Buffer.BlockCopy(aFrom, iData, aTo, iData, (int)pBt.UsableSize - iData);
Buffer.BlockCopy(aFrom, iFromHdr, aTo, iToHdr, pFrom.CellOffset + 2 * pFrom.Cells);
// Reinitialize page pTo so that the contents of the MemPage structure match the new data. The initialization of pTo can actually fail under
// fairly obscure circumstances, even though it is a copy of initialized page pFrom.
pTo.HasInit = false;
var rc = pTo.btreeInitPage();
if (rc != RC.OK)
{
pRC = rc;
return;
}
// If this is an auto-vacuum database, update the pointer-map entries for any b-tree or overflow pages that pTo now contains the pointers to.
#if !SQLITE_OMIT_AUTOVACUUM
if (pBt.AutoVacuum)
#else
if (false)
#endif
{
pRC = pTo.setChildPtrmaps();
}
}
internal static void copyNodeContent(MemPage pFrom, MemPage pTo, ref RC pRC)
{
if (pRC != RC.OK)
return;
var pBt = pFrom.Shared;
var aFrom = pFrom.Data;
var aTo = pTo.Data;
var iFromHdr = pFrom.HeaderOffset;
var iToHdr = (pTo.ID == 1 ? 100 : 0);
Debug.Assert(pFrom.HasInit);
Debug.Assert(pFrom.FreeBytes >= iToHdr);
Debug.Assert(ConvertEx.Get2(aFrom, iFromHdr + 5) <= (int)pBt.UsableSize);
// Copy the b-tree node content from page pFrom to page pTo.
var iData = (int)ConvertEx.Get2(aFrom, iFromHdr + 5);
Buffer.BlockCopy(aFrom, iData, aTo, iData, (int)pBt.UsableSize - iData);
Buffer.BlockCopy(aFrom, iFromHdr, aTo, iToHdr, pFrom.CellOffset + 2 * pFrom.Cells);
// Reinitialize page pTo so that the contents of the MemPage structure match the new data. The initialization of pTo can actually fail under
// fairly obscure circumstances, even though it is a copy of initialized page pFrom.
pTo.HasInit = false;
var rc = pTo.btreeInitPage();
if (rc != RC.OK)
{
pRC = rc;
return;
}
// If this is an auto-vacuum database, update the pointer-map entries for any b-tree or overflow pages that pTo now contains the pointers to.
#if !SQLITE_OMIT_AUTOVACUUM
if (pBt.AutoVacuum)
#else
if (false)
#endif
{
pRC = pTo.setChildPtrmaps();
}
}
internal static RC relocatePage(BtShared pBt, MemPage pDbPage, PTRMAP eType, Pgno iPtrPage, Pgno iFreePage, int isCommit)
{
var pPtrPage = new MemPage(); // The page that contains a pointer to pDbPage
var iDbPage = pDbPage.ID;
var pPager = pBt.Pager;
Debug.Assert(eType == PTRMAP.OVERFLOW2 || eType == PTRMAP.OVERFLOW1 || eType == PTRMAP.BTREE || eType == PTRMAP.ROOTPAGE);
Debug.Assert(MutexEx.Held(pBt.Mutex));
Debug.Assert(pDbPage.Shared == pBt);
// Move page iDbPage from its current location to page number iFreePage
Btree.TRACE("AUTOVACUUM: Moving %d to free page %d (ptr page %d type %d)\n", iDbPage, iFreePage, iPtrPage, eType);
var rc = pPager.sqlite3PagerMovepage(pDbPage.DbPage, iFreePage, isCommit);
if (rc != RC.OK)
{
return(rc);
}
pDbPage.ID = iFreePage;
// If pDbPage was a btree-page, then it may have child pages and/or cells that point to overflow pages. The pointer map entries for all these
// pages need to be changed.
// If pDbPage is an overflow page, then the first 4 bytes may store a pointer to a subsequent overflow page. If this is the case, then
// the pointer map needs to be updated for the subsequent overflow page.
if (eType == PTRMAP.BTREE || eType == PTRMAP.ROOTPAGE)
{
rc = pDbPage.setChildPtrmaps();
if (rc != RC.OK)
{
return(rc);
}
}
else
{
var nextOvfl = (Pgno)ConvertEx.Get4(pDbPage.Data);
if (nextOvfl != 0)
{
pBt.ptrmapPut(nextOvfl, PTRMAP.OVERFLOW2, iFreePage, ref rc);
if (rc != RC.OK)
{
return(rc);
}
}
}
// Fix the database pointer on page iPtrPage that pointed at iDbPage so that it points at iFreePage. Also fix the pointer map entry for iPtrPage.
if (eType != PTRMAP.ROOTPAGE)
{
rc = pBt.btreeGetPage(iPtrPage, ref pPtrPage, 0);
if (rc != RC.OK)
{
return(rc);
}
rc = Pager.Write(pPtrPage.DbPage);
if (rc != RC.OK)
{
pPtrPage.releasePage();
return(rc);
}
rc = pPtrPage.modifyPagePointer(iDbPage, iFreePage, eType);
pPtrPage.releasePage();
if (rc == RC.OK)
{
pBt.ptrmapPut(iFreePage, eType, iPtrPage, ref rc);
}
}
return(rc);
}
internal static RC relocatePage(BtShared pBt, MemPage pDbPage, PTRMAP eType, Pgno iPtrPage, Pgno iFreePage, int isCommit)
{
var pPtrPage = new MemPage(); // The page that contains a pointer to pDbPage
var iDbPage = pDbPage.ID;
var pPager = pBt.Pager;
Debug.Assert(eType == PTRMAP.OVERFLOW2 || eType == PTRMAP.OVERFLOW1 || eType == PTRMAP.BTREE || eType == PTRMAP.ROOTPAGE);
Debug.Assert(MutexEx.Held(pBt.Mutex));
Debug.Assert(pDbPage.Shared == pBt);
// Move page iDbPage from its current location to page number iFreePage
Btree.TRACE("AUTOVACUUM: Moving %d to free page %d (ptr page %d type %d)\n", iDbPage, iFreePage, iPtrPage, eType);
var rc = pPager.sqlite3PagerMovepage(pDbPage.DbPage, iFreePage, isCommit);
if (rc != RC.OK)
return rc;
pDbPage.ID = iFreePage;
// If pDbPage was a btree-page, then it may have child pages and/or cells that point to overflow pages. The pointer map entries for all these
// pages need to be changed.
// If pDbPage is an overflow page, then the first 4 bytes may store a pointer to a subsequent overflow page. If this is the case, then
// the pointer map needs to be updated for the subsequent overflow page.
if (eType == PTRMAP.BTREE || eType == PTRMAP.ROOTPAGE)
{
rc = pDbPage.setChildPtrmaps();
if (rc != RC.OK)
return rc;
}
else
{
var nextOvfl = (Pgno)ConvertEx.Get4(pDbPage.Data);
if (nextOvfl != 0)
{
pBt.ptrmapPut(nextOvfl, PTRMAP.OVERFLOW2, iFreePage, ref rc);
if (rc != RC.OK)
return rc;
}
}
// Fix the database pointer on page iPtrPage that pointed at iDbPage so that it points at iFreePage. Also fix the pointer map entry for iPtrPage.
if (eType != PTRMAP.ROOTPAGE)
{
rc = pBt.btreeGetPage(iPtrPage, ref pPtrPage, 0);
if (rc != RC.OK)
return rc;
rc = Pager.Write(pPtrPage.DbPage);
if (rc != RC.OK)
{
pPtrPage.releasePage();
return rc;
}
rc = pPtrPage.modifyPagePointer(iDbPage, iFreePage, eType);
pPtrPage.releasePage();
if (rc == RC.OK)
pBt.ptrmapPut(iFreePage, eType, iPtrPage, ref rc);
}
return rc;
}
