static int NB = (NN * 2 + 1); // Total pages involved in the balance
#endregion Fields
#if !SQLITE_OMIT_QUICKBALANCE
internal static RC balance_quick(MemPage parentPage, MemPage page, byte[] space)
{
Debug.Assert(MutexEx.Held(page.Shared.Mutex));
Debug.Assert(Pager.IsPageWriteable(parentPage.DbPage));
Debug.Assert(page.NOverflows == 1);
// This error condition is now caught prior to reaching this function
if (page.Cells <= 0)
return SysEx.SQLITE_CORRUPT_BKPT();
// Allocate a new page. This page will become the right-sibling of pPage. Make the parent page writable, so that the new divider cell
// may be inserted. If both these operations are successful, proceed.
var shared = page.Shared; // B-Tree Database
var newPage = new MemPage(); // Newly allocated page
Pgno pgnoNew = 0; // Page number of pNew
var rc = shared.allocateBtreePage(ref newPage, ref pgnoNew, 0, 0);
if (rc != RC.OK)
return rc;
var pOut = 4;
var pCell = page.Overflows[0].Cell;
var szCell = new int[1] { page.cellSizePtr(pCell) };
Debug.Assert(Pager.IsPageWriteable(newPage.DbPage));
Debug.Assert(page.Data[0] == (Btree.PTF_INTKEY | Btree.PTF_LEAFDATA | Btree.PTF_LEAF));
newPage.zeroPage(Btree.PTF_INTKEY | Btree.PTF_LEAFDATA | Btree.PTF_LEAF);
newPage.assemblePage(1, pCell, szCell);
// If this is an auto-vacuum database, update the pointer map with entries for the new page, and any pointer from the
// cell on the page to an overflow page. If either of these operations fails, the return code is set, but the contents
// of the parent page are still manipulated by thh code below. That is Ok, at this point the parent page is guaranteed to
// be marked as dirty. Returning an error code will cause a rollback, undoing any changes made to the parent page.
#if !SQLITE_OMIT_AUTOVACUUM
if (shared.AutoVacuum)
#else
if (false)
#endif
{
shared.ptrmapPut(pgnoNew, PTRMAP.BTREE, parentPage.ID, ref rc);
if (szCell[0] > newPage.MinLocal)
newPage.ptrmapPutOvflPtr(pCell, ref rc);
}
// Create a divider cell to insert into pParent. The divider cell consists of a 4-byte page number (the page number of pPage) and
// a variable length key value (which must be the same value as the largest key on pPage).
// To find the largest key value on pPage, first find the right-most cell on pPage. The first two fields of this cell are the
// record-length (a variable length integer at most 32-bits in size) and the key value (a variable length integer, may have any value).
// The first of the while(...) loops below skips over the record-length field. The second while(...) loop copies the key value from the
// cell on pPage into the pSpace buffer.
var iCell = page.FindCell(page.Cells - 1);
pCell = page.Data;
var _pCell = iCell;
var pStop = _pCell + 9;
while (((pCell[_pCell++]) & 0x80) != 0 && _pCell < pStop) ;
pStop = _pCell + 9;
while (((space[pOut++] = pCell[_pCell++]) & 0x80) != 0 && _pCell < pStop) ;
// Insert the new divider cell into pParent.
parentPage.insertCell(parentPage.Cells, space, pOut, null, page.ID, ref rc);
// Set the right-child pointer of pParent to point to the new page.
ConvertEx.Put4L(parentPage.Data, parentPage.HeaderOffset + 8, pgnoNew);
// Release the reference to the new page.
newPage.releasePage();
return rc;
}
internal RC clearDatabasePage(Pgno pgno, int freePageFlag, ref int pnChange)
{
var pPage = new MemPage();
Debug.Assert(MutexEx.Held(this.Mutex));
if (pgno > btreePagecount())
{
return(SysEx.SQLITE_CORRUPT_BKPT());
}
var rc = getAndInitPage(pgno, ref pPage);
if (rc != RC.OK)
{
return(rc);
}
for (var i = 0; i < pPage.Cells; i++)
{
var iCell = pPage.FindCell(i);
var pCell = pPage.Data;
if (pPage.Leaf == 0)
{
rc = clearDatabasePage(ConvertEx.Get4(pCell, iCell), 1, ref pnChange);
if (rc != RC.OK)
{
goto cleardatabasepage_out;
}
}
rc = pPage.clearCell(iCell);
if (rc != RC.OK)
{
goto cleardatabasepage_out;
}
}
if (pPage.Leaf == 0)
{
rc = clearDatabasePage(ConvertEx.Get4(pPage.Data, 8), 1, ref pnChange);
if (rc != RC.OK)
{
goto cleardatabasepage_out;
}
}
else
{
pnChange += pPage.Cells;
}
if (freePageFlag != 0)
{
pPage.freePage(ref rc);
}
else if ((rc = Pager.Write(pPage.DbPage)) == RC.OK)
{
pPage.zeroPage(pPage.Data[0] | Btree.PTF_LEAF);
}
cleardatabasepage_out:
pPage.releasePage();
return(rc);
}
internal RC getOverflowPage(Pgno ovfl, out MemPage ppPage, out Pgno pPgnoNext)
{
Pgno next = 0;
MemPage pPage = null;
ppPage = null;
var rc = RC.OK;
Debug.Assert(MutexEx.Held(this.Mutex));
// Debug.Assert( pPgnoNext != 0);
#if !SQLITE_OMIT_AUTOVACUUM
// Try to find the next page in the overflow list using the autovacuum pointer-map pages. Guess that the next page in
// the overflow list is page number (ovfl+1). If that guess turns out to be wrong, fall back to loading the data of page
// number ovfl to determine the next page number.
if (this.AutoVacuum)
{
Pgno pgno = 0;
Pgno iGuess = ovfl + 1;
PTRMAP eType = 0;
while (MemPage.PTRMAP_ISPAGE(this, iGuess) || iGuess == MemPage.PENDING_BYTE_PAGE(this))
{
iGuess++;
}
if (iGuess <= btreePagecount())
{
rc = ptrmapGet(iGuess, ref eType, ref pgno);
if (rc == RC.OK && eType == PTRMAP.OVERFLOW2 && pgno == ovfl)
{
next = iGuess;
rc = RC.DONE;
}
}
}
#endif
Debug.Assert(next == 0 || rc == RC.DONE);
if (rc == RC.OK)
{
rc = btreeGetPage(ovfl, ref pPage, 0);
Debug.Assert(rc == RC.OK || pPage == null);
if (rc == RC.OK)
{
next = ConvertEx.Get4(pPage.Data);
}
}
pPgnoNext = next;
if (ppPage != null)
{
ppPage = pPage;
}
else
{
pPage.releasePage();
}
return(rc == RC.DONE ? RC.OK : rc);
}
internal static RC balance_deeper(MemPage pRoot, ref MemPage ppChild)
{
MemPage pChild = null; // Pointer to a new child page
Pgno pgnoChild = 0; // Page number of the new child page
var pBt = pRoot.Shared;
Debug.Assert(pRoot.NOverflows > 0);
Debug.Assert(MutexEx.Held(pBt.Mutex));
// Make pRoot, the root page of the b-tree, writable. Allocate a new page that will become the new right-child of pPage. Copy the contents
// of the node stored on pRoot into the new child page.
var rc = Pager.Write(pRoot.DbPage);
if (rc == RC.OK)
{
rc = pBt.allocateBtreePage(ref pChild, ref pgnoChild, pRoot.ID, 0);
copyNodeContent(pRoot, pChild, ref rc);
#if !SQLITE_OMIT_AUTOVACUUM
if (pBt.AutoVacuum)
#else
if (false)
#endif
{
pBt.ptrmapPut(pgnoChild, PTRMAP.BTREE, pRoot.ID, ref rc);
}
}
if (rc != RC.OK)
{
ppChild = null;
pChild.releasePage();
return(rc);
}
Debug.Assert(Pager.IsPageWriteable(pChild.DbPage));
Debug.Assert(Pager.IsPageWriteable(pRoot.DbPage));
Debug.Assert(pChild.Cells == pRoot.Cells);
Btree.TRACE("BALANCE: copy root %d into %d\n", pRoot.ID, pChild.ID);
// Copy the overflow cells from pRoot to pChild
Array.Copy(pRoot.Overflows, pChild.Overflows, pRoot.NOverflows);
pChild.NOverflows = pRoot.NOverflows;
// Zero the contents of pRoot. Then install pChild as the right-child.
pRoot.zeroPage(pChild.Data[0] & ~Btree.PTF_LEAF);
ConvertEx.Put4L(pRoot.Data, pRoot.HeaderOffset + 8, pgnoChild);
ppChild = pChild;
return(RC.OK);
}
internal RC getAndInitPage(Pgno pgno, ref MemPage ppPage)
{
Debug.Assert(MutexEx.Held(this.Mutex));
RC rc;
if (pgno > btreePagecount())
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
}
else
{
rc = btreeGetPage(pgno, ref ppPage, 0);
if (rc == RC.OK)
{
rc = ppPage.btreeInitPage();
if (rc != RC.OK)
{
ppPage.releasePage();
}
}
}
Debug.Assert(pgno != 0 || rc == RC.CORRUPT);
return(rc);
}
internal RC fillInCell(byte[] pCell, byte[] pKey, long nKey, byte[] pData, int nData, int nZero, ref int pnSize)
{
Debug.Assert(MutexEx.Held(this.Shared.Mutex));
// pPage is not necessarily writeable since pCell might be auxiliary buffer space that is separate from the pPage buffer area
// TODO -- Determine if the following Assert is needed under c#
//Debug.Assert( pCell < pPage.aData || pCell >= &pPage.aData[pBt.pageSize] || sqlite3PagerIswriteable(pPage.pDbPage) );
// Fill in the header.
var nHeader = 0;
if (this.Leaf == 0)
{
nHeader += 4;
}
if (this.HasData != 0)
{
nHeader += (int)ConvertEx.PutVariant9(pCell, (uint)nHeader, (int)(nData + nZero));
}
else
{
nData = nZero = 0;
}
nHeader += ConvertEx.PutVariant9L(pCell, (uint)nHeader, (ulong)nKey);
var info = new CellInfo();
btreeParseCellPtr(pCell, ref info);
Debug.Assert(info.nHeader == nHeader);
Debug.Assert(info.nKey == nKey);
Debug.Assert(info.nData == (uint)(nData + nZero));
// Fill in the payload
var nPayload = nData + nZero;
byte[] pSrc;
int nSrc;
if (this.HasIntKey)
{
pSrc = pData;
nSrc = nData;
nData = 0;
}
else
{
if (Check.NEVER(nKey > 0x7fffffff || pKey == null))
{
return(SysEx.SQLITE_CORRUPT_BKPT());
}
nPayload += (int)nKey;
pSrc = pKey;
nSrc = (int)nKey;
}
pnSize = info.nSize;
var spaceLeft = (int)info.nLocal;
var pPayload = pCell;
var pPayloadIndex = nHeader;
var pPrior = pCell;
var pPriorIndex = (int)info.iOverflow;
var pBt = this.Shared;
Pgno pgnoOvfl = 0;
MemPage pToRelease = null;
while (nPayload > 0)
{
if (spaceLeft == 0)
{
#if !SQLITE_OMIT_AUTOVACUUM
var pgnoPtrmap = pgnoOvfl; // Overflow page pointer-map entry page
if (pBt.AutoVacuum)
{
do
{
pgnoOvfl++;
}while (PTRMAP_ISPAGE(pBt, pgnoOvfl) || pgnoOvfl == PENDING_BYTE_PAGE(pBt));
}
#endif
MemPage pOvfl = null;
var rc = pBt.allocateBtreePage(ref pOvfl, ref pgnoOvfl, pgnoOvfl, 0);
#if !SQLITE_OMIT_AUTOVACUUM
// If the database supports auto-vacuum, and the second or subsequent overflow page is being allocated, add an entry to the pointer-map for that page now.
// If this is the first overflow page, then write a partial entry to the pointer-map. If we write nothing to this pointer-map slot,
// then the optimistic overflow chain processing in clearCell() may misinterpret the uninitialised values and delete the
// wrong pages from the database.
if (pBt.AutoVacuum && rc == RC.OK)
{
var eType = (pgnoPtrmap != 0 ? PTRMAP.OVERFLOW2 : PTRMAP.OVERFLOW1);
pBt.ptrmapPut(pgnoOvfl, eType, pgnoPtrmap, ref rc);
if (rc != RC.OK)
{
pOvfl.releasePage();
}
}
#endif
if (rc != RC.OK)
{
pToRelease.releasePage();
return(rc);
}
// If pToRelease is not zero than pPrior points into the data area of pToRelease. Make sure pToRelease is still writeable.
Debug.Assert(pToRelease == null || Pager.IsPageWriteable(pToRelease.DbPage));
// If pPrior is part of the data area of pPage, then make sure pPage is still writeable
// TODO -- Determine if the following Assert is needed under c#
//Debug.Assert( pPrior < pPage.aData || pPrior >= &pPage.aData[pBt.pageSize] || sqlite3PagerIswriteable(pPage.pDbPage) );
ConvertEx.Put4L(pPrior, (uint)pPriorIndex, pgnoOvfl);
pToRelease.releasePage();
pToRelease = pOvfl;
pPrior = pOvfl.Data;
pPriorIndex = 0;
ConvertEx.Put4(pPrior, 0);
pPayload = pOvfl.Data;
pPayloadIndex = 4;
spaceLeft = (int)pBt.UsableSize - 4;
}
var n = nPayload;
if (n > spaceLeft)
{
n = spaceLeft;
}
// If pToRelease is not zero than pPayload points into the data area of pToRelease. Make sure pToRelease is still writeable.
Debug.Assert(pToRelease == null || Pager.IsPageWriteable(pToRelease.DbPage));
// If pPayload is part of the data area of pPage, then make sure pPage is still writeable
// TODO -- Determine if the following Assert is needed under c#
//Debug.Assert( pPayload < pPage.aData || pPayload >= &pPage.aData[pBt.pageSize] || sqlite3PagerIswriteable(pPage.pDbPage) );
var pSrcIndex = 0;
if (nSrc > 0)
{
if (n > nSrc)
{
n = nSrc;
}
Debug.Assert(pSrc != null);
Buffer.BlockCopy(pSrc, pSrcIndex, pPayload, pPayloadIndex, n);
}
else
{
var pZeroBlob = MallocEx.sqlite3Malloc(n);
Buffer.BlockCopy(pZeroBlob, 0, pPayload, pPayloadIndex, n);
}
nPayload -= n;
pPayloadIndex += n;
pSrcIndex += n;
nSrc -= n;
spaceLeft -= n;
if (nSrc == 0)
{
nSrc = nData;
pSrc = pData;
}
}
pToRelease.releasePage();
return(RC.OK);
}
internal RC freePage2(MemPage pMemPage, Pgno iPage)
{
MemPage pTrunk = null; // Free-list trunk page
var pPage1 = this.Page1; // Local reference to page 1
Debug.Assert(MutexEx.Held(this.Mutex));
Debug.Assert(iPage > 1);
Debug.Assert(pMemPage == null || pMemPage.ID == iPage);
MemPage pPage; // Page being freed. May be NULL.
if (pMemPage != null)
{
pPage = pMemPage;
Pager.AddPageRef(pPage.DbPage);
}
else
{
pPage = btreePageLookup(iPage);
}
// Increment the free page count on pPage1
var rc = Pager.Write(pPage1.DbPage);
if (rc != RC.OK)
{
goto freepage_out;
}
var nFree = (int)ConvertEx.Get4(pPage1.Data, 36); // Initial number of pages on free-list
ConvertEx.Put4(pPage1.Data, 36, nFree + 1);
if (this.SecureDelete)
{
// If the secure_delete option is enabled, then always fully overwrite deleted information with zeros.
if ((pPage == null && ((rc = btreeGetPage(iPage, ref pPage, 0)) != RC.OK)) || ((rc = Pager.Write(pPage.DbPage)) != RC.OK))
{
goto freepage_out;
}
Array.Clear(pPage.Data, 0, (int)pPage.Shared.PageSize);
}
// If the database supports auto-vacuum, write an entry in the pointer-map to indicate that the page is free.
#if !SQLITE_OMIT_AUTOVACUUM
if (this.AutoVacuum)
#else
if (false)
#endif
{
ptrmapPut(iPage, PTRMAP.FREEPAGE, 0, ref rc);
if (rc != RC.OK)
{
goto freepage_out;
}
}
// Now manipulate the actual database free-list structure. There are two possibilities. If the free-list is currently empty, or if the first
// trunk page in the free-list is full, then this page will become a new free-list trunk page. Otherwise, it will become a leaf of the
// first trunk page in the current free-list. This block tests if it is possible to add the page as a new free-list leaf.
Pgno iTrunk = 0; // Page number of free-list trunk page
if (nFree != 0)
{
uint nLeaf; // Initial number of leaf cells on trunk page
iTrunk = (Pgno)ConvertEx.Get4(pPage1.Data, 32); // Page number of free-list trunk page
rc = btreeGetPage(iTrunk, ref pTrunk, 0);
if (rc != RC.OK)
{
goto freepage_out;
}
nLeaf = ConvertEx.Get4(pTrunk.Data, 4);
Debug.Assert(this.UsableSize > 32);
if (nLeaf > (uint)this.UsableSize / 4 - 2)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto freepage_out;
}
if (nLeaf < (uint)this.UsableSize / 4 - 8)
{
// In this case there is room on the trunk page to insert the page being freed as a new leaf.
// Note: that the trunk page is not really full until it contains usableSize/4 - 2 entries, not usableSize/4 - 8 entries as we have
// coded. But due to a coding error in versions of SQLite prior to 3.6.0, databases with freelist trunk pages holding more than
// usableSize/4 - 8 entries will be reported as corrupt. In order to maintain backwards compatibility with older versions of SQLite,
// we will continue to restrict the number of entries to usableSize/4 - 8 for now. At some point in the future (once everyone has upgraded
// to 3.6.0 or later) we should consider fixing the conditional above to read "usableSize/4-2" instead of "usableSize/4-8".
rc = Pager.Write(pTrunk.DbPage);
if (rc == RC.OK)
{
ConvertEx.Put4(pTrunk.Data, 4, nLeaf + 1);
ConvertEx.Put4(pTrunk.Data, (uint)(8 + nLeaf * 4), iPage);
if (pPage != null && !this.SecureDelete)
{
Pager.DontWrite(pPage.DbPage);
}
rc = btreeSetHasContent(iPage);
}
Btree.TRACE("FREE-PAGE: %d leaf on trunk page %d\n", iPage, pTrunk.ID);
goto freepage_out;
}
}
// If control flows to this point, then it was not possible to add the the page being freed as a leaf page of the first trunk in the free-list.
// Possibly because the free-list is empty, or possibly because the first trunk in the free-list is full. Either way, the page being freed
// will become the new first trunk page in the free-list.
if (pPage == null && (rc = btreeGetPage(iPage, ref pPage, 0)) != RC.OK)
{
goto freepage_out;
}
rc = Pager.Write(pPage.DbPage);
if (rc != RC.OK)
{
goto freepage_out;
}
ConvertEx.Put4L(pPage.Data, iTrunk);
ConvertEx.Put4(pPage.Data, 4, 0);
ConvertEx.Put4(pPage1.Data, 32, iPage);
Btree.TRACE("FREE-PAGE: %d new trunk page replacing %d\n", pPage.ID, iTrunk);
freepage_out:
if (pPage != null)
{
pPage.HasInit = false;
}
pPage.releasePage();
pTrunk.releasePage();
return(rc);
}
internal RC allocateBtreePage(ref MemPage ppPage, ref Pgno pPgno, Pgno nearby, byte exact)
{
MemPage pTrunk = null;
MemPage pPrevTrunk = null;
Debug.Assert(MutexEx.Held(this.Mutex));
var pPage1 = this.Page1;
var mxPage = btreePagecount(); // Total size of the database file
var n = ConvertEx.Get4(pPage1.Data, 36); // Number of pages on the freelist
if (n >= mxPage)
{
return(SysEx.SQLITE_CORRUPT_BKPT());
}
RC rc;
if (n > 0)
{
// There are pages on the freelist. Reuse one of those pages.
Pgno iTrunk;
byte searchList = 0; // If the free-list must be searched for 'nearby'
// If the 'exact' parameter was true and a query of the pointer-map shows that the page 'nearby' is somewhere on the free-list, then the entire-list will be searched for that page.
#if !SQLITE_OMIT_AUTOVACUUM
if (exact != 0 && nearby <= mxPage)
{
Debug.Assert(nearby > 0);
Debug.Assert(this.AutoVacuum);
PTRMAP eType = 0;
uint dummy0 = 0;
rc = ptrmapGet(nearby, ref eType, ref dummy0);
if (rc != RC.OK)
{
return(rc);
}
if (eType == PTRMAP.FREEPAGE)
{
searchList = 1;
}
pPgno = nearby;
}
#endif
// Decrement the free-list count by 1. Set iTrunk to the index of the first free-list trunk page. iPrevTrunk is initially 1.
rc = Pager.Write(pPage1.DbPage);
if (rc != RC.OK)
{
return(rc);
}
ConvertEx.Put4(pPage1.Data, 36, n - 1);
// The code within this loop is run only once if the 'searchList' variable is not true. Otherwise, it runs once for each trunk-page on the
// free-list until the page 'nearby' is located.
do
{
pPrevTrunk = pTrunk;
iTrunk = (pPrevTrunk != null ? ConvertEx.Get4(pPrevTrunk.Data, 0) : ConvertEx.Get4(pPage1.Data, 32));
rc = (iTrunk > mxPage ? SysEx.SQLITE_CORRUPT_BKPT() : btreeGetPage(iTrunk, ref pTrunk, 0));
if (rc != RC.OK)
{
pTrunk = null;
goto end_allocate_page;
}
var k = ConvertEx.Get4(pTrunk.Data, 4); // # of leaves on this trunk page
if (k == 0 && searchList == 0)
{
// The trunk has no leaves and the list is not being searched. So extract the trunk page itself and use it as the newly allocated page
Debug.Assert(pPrevTrunk == null);
rc = Pager.Write(pTrunk.DbPage);
if (rc != RC.OK)
{
goto end_allocate_page;
}
pPgno = iTrunk;
Buffer.BlockCopy(pTrunk.Data, 0, pPage1.Data, 32, 4);
ppPage = pTrunk;
pTrunk = null;
Btree.TRACE("ALLOCATE: %d trunk - %d free pages left\n", pPgno, n - 1);
}
else if (k > (uint)(this.UsableSize / 4 - 2))
{
// Value of k is out of range. Database corruption
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
#if !SQLITE_OMIT_AUTOVACUUM
}
else if (searchList != 0 && nearby == iTrunk)
{
// The list is being searched and this trunk page is the page to allocate, regardless of whether it has leaves.
Debug.Assert(pPgno == iTrunk);
ppPage = pTrunk;
searchList = 0;
rc = Pager.Write(pTrunk.DbPage);
if (rc != RC.OK)
{
goto end_allocate_page;
}
if (k == 0)
{
if (pPrevTrunk == null)
{
pPage1.Data[32 + 0] = pTrunk.Data[0 + 0];
pPage1.Data[32 + 1] = pTrunk.Data[0 + 1];
pPage1.Data[32 + 2] = pTrunk.Data[0 + 2];
pPage1.Data[32 + 3] = pTrunk.Data[0 + 3];
}
else
{
rc = Pager.Write(pPrevTrunk.DbPage);
if (rc != RC.OK)
{
goto end_allocate_page;
}
pPrevTrunk.Data[0 + 0] = pTrunk.Data[0 + 0];
pPrevTrunk.Data[0 + 1] = pTrunk.Data[0 + 1];
pPrevTrunk.Data[0 + 2] = pTrunk.Data[0 + 2];
pPrevTrunk.Data[0 + 3] = pTrunk.Data[0 + 3];
}
}
else
{
// The trunk page is required by the caller but it contains pointers to free-list leaves. The first leaf becomes a trunk page in this case.
var pNewTrunk = new MemPage();
var iNewTrunk = (Pgno)ConvertEx.Get4(pTrunk.Data, 8);
if (iNewTrunk > mxPage)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
}
rc = btreeGetPage(iNewTrunk, ref pNewTrunk, 0);
if (rc != RC.OK)
{
goto end_allocate_page;
}
rc = Pager.Write(pNewTrunk.DbPage);
if (rc != RC.OK)
{
pNewTrunk.releasePage();
goto end_allocate_page;
}
pNewTrunk.Data[0 + 0] = pTrunk.Data[0 + 0];
pNewTrunk.Data[0 + 1] = pTrunk.Data[0 + 1];
pNewTrunk.Data[0 + 2] = pTrunk.Data[0 + 2];
pNewTrunk.Data[0 + 3] = pTrunk.Data[0 + 3];
ConvertEx.Put4(pNewTrunk.Data, 4, (uint)(k - 1));
Buffer.BlockCopy(pTrunk.Data, 12, pNewTrunk.Data, 8, (int)(k - 1) * 4);
pNewTrunk.releasePage();
if (pPrevTrunk == null)
{
Debug.Assert(Pager.IsPageWriteable(pPage1.DbPage));
ConvertEx.Put4(pPage1.Data, 32, iNewTrunk);
}
else
{
rc = Pager.Write(pPrevTrunk.DbPage);
if (rc != RC.OK)
{
goto end_allocate_page;
}
ConvertEx.Put4(pPrevTrunk.Data, 0, iNewTrunk);
}
}
pTrunk = null;
Btree.TRACE("ALLOCATE: %d trunk - %d free pages left\n", pPgno, n - 1);
#endif
}
else if (k > 0)
{
// Extract a leaf from the trunk
uint closest;
var aData = pTrunk.Data;
if (nearby > 0)
{
closest = 0;
var dist = Math.Abs((int)(ConvertEx.Get4(aData, 8) - nearby));
for (uint i = 1; i < k; i++)
{
int dist2 = Math.Abs((int)(ConvertEx.Get4(aData, 8 + i * 4) - nearby));
if (dist2 < dist)
{
closest = i;
dist = dist2;
}
}
}
else
{
closest = 0;
}
//
var iPage = (Pgno)ConvertEx.Get4(aData, 8 + closest * 4);
if (iPage > mxPage)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
}
if (searchList == 0 || iPage == nearby)
{
pPgno = iPage;
Btree.TRACE("ALLOCATE: %d was leaf %d of %d on trunk %d" + ": %d more free pages\n", pPgno, closest + 1, k, pTrunk.ID, n - 1);
rc = Pager.Write(pTrunk.DbPage);
if (rc != RC.OK)
{
goto end_allocate_page;
}
if (closest < k - 1)
{
Buffer.BlockCopy(aData, (int)(4 + k * 4), aData, 8 + (int)closest * 4, 4);
}
ConvertEx.Put4(aData, 4, (k - 1));
var noContent = (!btreeGetHasContent(pPgno) ? 1 : 0);
rc = btreeGetPage(pPgno, ref ppPage, noContent);
if (rc == RC.OK)
{
rc = Pager.Write((ppPage).DbPage);
if (rc != RC.OK)
{
ppPage.releasePage();
}
}
searchList = 0;
}
}
pPrevTrunk.releasePage();
pPrevTrunk = null;
} while (searchList != 0);
}
else
{
// There are no pages on the freelist, so create a new page at the end of the file
rc = Pager.Write(this.Page1.DbPage);
if (rc != RC.OK)
{
return(rc);
}
this.Pages++;
if (this.Pages == MemPage.PENDING_BYTE_PAGE(this))
{
this.Pages++;
}
#if !SQLITE_OMIT_AUTOVACUUM
if (this.AutoVacuum && MemPage.PTRMAP_ISPAGE(this, this.Pages))
{
// If pPgno refers to a pointer-map page, allocate two new pages at the end of the file instead of one. The first allocated page
// becomes a new pointer-map page, the second is used by the caller.
MemPage pPg = null;
Btree.TRACE("ALLOCATE: %d from end of file (pointer-map page)\n", pPgno);
Debug.Assert(this.Pages != MemPage.PENDING_BYTE_PAGE(this));
rc = btreeGetPage(this.Pages, ref pPg, 1);
if (rc == RC.OK)
{
rc = Pager.Write(pPg.DbPage);
pPg.releasePage();
}
if (rc != RC.OK)
{
return(rc);
}
this.Pages++;
if (this.Pages == MemPage.PENDING_BYTE_PAGE(this))
{
this.Pages++;
}
}
#endif
ConvertEx.Put4(this.Page1.Data, 28, this.Pages);
pPgno = this.Pages;
Debug.Assert(pPgno != MemPage.PENDING_BYTE_PAGE(this));
rc = btreeGetPage(pPgno, ref ppPage, 1);
if (rc != RC.OK)
{
return(rc);
}
rc = Pager.Write((ppPage).DbPage);
if (rc != RC.OK)
{
ppPage.releasePage();
}
Btree.TRACE("ALLOCATE: %d from end of file\n", pPgno);
}
Debug.Assert(pPgno != MemPage.PENDING_BYTE_PAGE(this));
end_allocate_page:
pTrunk.releasePage();
pPrevTrunk.releasePage();
if (rc == RC.OK)
{
if (Pager.GetPageRefCount((ppPage).DbPage) > 1)
{
ppPage.releasePage();
return(SysEx.SQLITE_CORRUPT_BKPT());
}
(ppPage).HasInit = false;
}
else
{
ppPage = null;
}
Debug.Assert(rc != RC.OK || Pager.IsPageWriteable((ppPage).DbPage));
return(rc);
}
internal static RC incrVacuumStep(BtShared pBt, Pgno nFin, Pgno iLastPg)
{
Pgno nFreeList; // Number of pages still on the free-list
Debug.Assert(MutexEx.Held(pBt.Mutex));
Debug.Assert(iLastPg > nFin);
if (!PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg != PENDING_BYTE_PAGE(pBt))
{
PTRMAP eType = 0;
Pgno iPtrPage = 0;
nFreeList = ConvertEx.Get4(pBt.Page1.Data, 36);
if (nFreeList == 0)
{
return(RC.DONE);
}
var rc = pBt.ptrmapGet(iLastPg, ref eType, ref iPtrPage);
if (rc != RC.OK)
{
return(rc);
}
if (eType == PTRMAP.ROOTPAGE)
{
return(SysEx.SQLITE_CORRUPT_BKPT());
}
if (eType == PTRMAP.FREEPAGE)
{
if (nFin == 0)
{
// Remove the page from the files free-list. This is not required if nFin is non-zero. In that case, the free-list will be
// truncated to zero after this function returns, so it doesn't matter if it still contains some garbage entries.
Pgno iFreePg = 0;
var pFreePg = new MemPage();
rc = pBt.allocateBtreePage(ref pFreePg, ref iFreePg, iLastPg, 1);
if (rc != RC.OK)
{
return(rc);
}
Debug.Assert(iFreePg == iLastPg);
pFreePg.releasePage();
}
}
else
{
Pgno iFreePg = 0; // Index of free page to move pLastPg to
var pLastPg = new MemPage();
rc = pBt.btreeGetPage(iLastPg, ref pLastPg, 0);
if (rc != RC.OK)
{
return(rc);
}
// If nFin is zero, this loop runs exactly once and page pLastPg is swapped with the first free page pulled off the free list.
// On the other hand, if nFin is greater than zero, then keep looping until a free-page located within the first nFin pages of the file is found.
do
{
var pFreePg = new MemPage();
rc = pBt.allocateBtreePage(ref pFreePg, ref iFreePg, 0, 0);
if (rc != RC.OK)
{
pLastPg.releasePage();
return(rc);
}
pFreePg.releasePage();
} while (nFin != 0 && iFreePg > nFin);
Debug.Assert(iFreePg < iLastPg);
rc = Pager.Write(pLastPg.DbPage);
if (rc == RC.OK)
{
rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg, (nFin != 0) ? 1 : 0);
}
pLastPg.releasePage();
if (rc != RC.OK)
{
return(rc);
}
}
}
if (nFin == 0)
{
iLastPg--;
while (iLastPg == PENDING_BYTE_PAGE(pBt) || PTRMAP_ISPAGE(pBt, iLastPg))
{
if (PTRMAP_ISPAGE(pBt, iLastPg))
{
var pPg = new MemPage();
var rc = pBt.btreeGetPage(iLastPg, ref pPg, 0);
if (rc != RC.OK)
{
return(rc);
}
rc = Pager.Write(pPg.DbPage);
pPg.releasePage();
if (rc != RC.OK)
{
return(rc);
}
}
iLastPg--;
}
pBt.Pager.TruncateImage(iLastPg);
pBt.Pages = iLastPg;
}
return(RC.OK);
}
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 RC btreeDropTable(Pgno iTable, ref int piMoved)
{
MemPage pPage = null;
var pBt = this.Shared;
Debug.Assert(sqlite3BtreeHoldsMutex());
Debug.Assert(this.InTransaction == TRANS.WRITE);
// It is illegal to drop a table if any cursors are open on the database. This is because in auto-vacuum mode the backend may
// need to move another root-page to fill a gap left by the deleted root page. If an open cursor was using this page a problem would occur.
// This error is caught long before control reaches this point.
if (Check.NEVER(pBt.Cursors) != null)
{
sqlite3b.sqlite3ConnectionBlocked(this.DB, pBt.Cursors.Tree.DB);
return(RC.LOCKED_SHAREDCACHE);
}
var rc = pBt.btreeGetPage((Pgno)iTable, ref pPage, 0);
if (rc != RC.OK)
{
return(rc);
}
var dummy0 = 0;
rc = ClearTable((int)iTable, ref dummy0);
if (rc != RC.OK)
{
pPage.releasePage();
return(rc);
}
piMoved = 0;
if (iTable > 1)
{
#if SQLITE_OMIT_AUTOVACUUM
freePage(pPage, ref rc);
releasePage(pPage);
#else
if (pBt.AutoVacuum)
{
Pgno maxRootPgno = 0;
GetMeta((int)META.LARGEST_ROOT_PAGE, ref maxRootPgno);
if (iTable == maxRootPgno)
{
// If the table being dropped is the table with the largest root-page number in the database, put the root page on the free list.
pPage.freePage(ref rc);
pPage.releasePage();
if (rc != RC.OK)
{
return(rc);
}
}
else
{
// The table being dropped does not have the largest root-page number in the database. So move the page that does into the
// gap left by the deleted root-page.
var pMove = new MemPage();
pPage.releasePage();
rc = pBt.btreeGetPage(maxRootPgno, ref pMove, 0);
if (rc != RC.OK)
{
return(rc);
}
rc = MemPage.relocatePage(pBt, pMove, PTRMAP.ROOTPAGE, 0, iTable, 0);
pMove.releasePage();
if (rc != RC.OK)
{
return(rc);
}
pMove = null;
rc = pBt.btreeGetPage(maxRootPgno, ref pMove, 0);
pMove.freePage(ref rc);
pMove.releasePage();
if (rc != RC.OK)
{
return(rc);
}
piMoved = (int)maxRootPgno;
}
// Set the new 'max-root-page' value in the database header. This is the old value less one, less one more if that happens to
// be a root-page number, less one again if that is the PENDING_BYTE_PAGE.
maxRootPgno--;
while (maxRootPgno == MemPage.PENDING_BYTE_PAGE(pBt) || MemPage.PTRMAP_ISPAGE(pBt, maxRootPgno))
{
maxRootPgno--;
}
Debug.Assert(maxRootPgno != MemPage.PENDING_BYTE_PAGE(pBt));
rc = SetMeta(4, maxRootPgno);
}
else
{
pPage.freePage(ref rc);
pPage.releasePage();
}
#endif
}
else
{
// If sqlite3BtreeDropTable was called on page 1. This really never should happen except in a corrupt database.
pPage.zeroPage(PTF_INTKEY | PTF_LEAF);
pPage.releasePage();
}
return(rc);
}
internal RC clearDatabasePage(Pgno pgno, int freePageFlag, ref int pnChange)
{
var pPage = new MemPage();
Debug.Assert(MutexEx.Held(this.Mutex));
if (pgno > btreePagecount())
return SysEx.SQLITE_CORRUPT_BKPT();
var rc = getAndInitPage(pgno, ref pPage);
if (rc != RC.OK)
return rc;
for (var i = 0; i < pPage.Cells; i++)
{
var iCell = pPage.FindCell(i);
var pCell = pPage.Data;
if (pPage.Leaf == 0)
{
rc = clearDatabasePage(ConvertEx.Get4(pCell, iCell), 1, ref pnChange);
if (rc != RC.OK)
goto cleardatabasepage_out;
}
rc = pPage.clearCell(iCell);
if (rc != RC.OK)
goto cleardatabasepage_out;
}
if (pPage.Leaf == 0)
{
rc = clearDatabasePage(ConvertEx.Get4(pPage.Data, 8), 1, ref pnChange);
if (rc != RC.OK)
goto cleardatabasepage_out;
}
else
pnChange += pPage.Cells;
if (freePageFlag != 0)
pPage.freePage(ref rc);
else if ((rc = Pager.Write(pPage.DbPage)) == RC.OK)
pPage.zeroPage(pPage.Data[0] | Btree.PTF_LEAF);
cleardatabasepage_out:
pPage.releasePage();
return rc;
}
internal RC btreeDropTable(Pgno iTable, ref int piMoved)
{
MemPage pPage = null;
var pBt = this.Shared;
Debug.Assert(sqlite3BtreeHoldsMutex());
Debug.Assert(this.InTransaction == TRANS.WRITE);
// It is illegal to drop a table if any cursors are open on the database. This is because in auto-vacuum mode the backend may
// need to move another root-page to fill a gap left by the deleted root page. If an open cursor was using this page a problem would occur.
// This error is caught long before control reaches this point.
if (Check.NEVER(pBt.Cursors) != null)
{
sqlite3b.sqlite3ConnectionBlocked(this.DB, pBt.Cursors.Tree.DB);
return RC.LOCKED_SHAREDCACHE;
}
var rc = pBt.btreeGetPage((Pgno)iTable, ref pPage, 0);
if (rc != RC.OK)
return rc;
var dummy0 = 0;
rc = ClearTable((int)iTable, ref dummy0);
if (rc != RC.OK)
{
pPage.releasePage();
return rc;
}
piMoved = 0;
if (iTable > 1)
{
#if SQLITE_OMIT_AUTOVACUUM
freePage(pPage, ref rc);
releasePage(pPage);
#else
if (pBt.AutoVacuum)
{
Pgno maxRootPgno = 0;
GetMeta((int)META.LARGEST_ROOT_PAGE, ref maxRootPgno);
if (iTable == maxRootPgno)
{
// If the table being dropped is the table with the largest root-page number in the database, put the root page on the free list.
pPage.freePage(ref rc);
pPage.releasePage();
if (rc != RC.OK)
return rc;
}
else
{
// The table being dropped does not have the largest root-page number in the database. So move the page that does into the
// gap left by the deleted root-page.
var pMove = new MemPage();
pPage.releasePage();
rc = pBt.btreeGetPage(maxRootPgno, ref pMove, 0);
if (rc != RC.OK)
return rc;
rc = MemPage.relocatePage(pBt, pMove, PTRMAP.ROOTPAGE, 0, iTable, 0);
pMove.releasePage();
if (rc != RC.OK)
return rc;
pMove = null;
rc = pBt.btreeGetPage(maxRootPgno, ref pMove, 0);
pMove.freePage(ref rc);
pMove.releasePage();
if (rc != RC.OK)
return rc;
piMoved = (int)maxRootPgno;
}
// Set the new 'max-root-page' value in the database header. This is the old value less one, less one more if that happens to
// be a root-page number, less one again if that is the PENDING_BYTE_PAGE.
maxRootPgno--;
while (maxRootPgno == MemPage.PENDING_BYTE_PAGE(pBt) || MemPage.PTRMAP_ISPAGE(pBt, maxRootPgno))
maxRootPgno--;
Debug.Assert(maxRootPgno != MemPage.PENDING_BYTE_PAGE(pBt));
rc = SetMeta(4, maxRootPgno);
}
else
{
pPage.freePage(ref rc);
pPage.releasePage();
}
#endif
}
else
{
// If sqlite3BtreeDropTable was called on page 1. This really never should happen except in a corrupt database.
pPage.zeroPage(PTF_INTKEY | PTF_LEAF);
pPage.releasePage();
}
return rc;
}
internal static RC incrVacuumStep(BtShared pBt, Pgno nFin, Pgno iLastPg)
{
Pgno nFreeList; // Number of pages still on the free-list
Debug.Assert(MutexEx.Held(pBt.Mutex));
Debug.Assert(iLastPg > nFin);
if (!PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg != PENDING_BYTE_PAGE(pBt))
{
PTRMAP eType = 0;
Pgno iPtrPage = 0;
nFreeList = ConvertEx.Get4(pBt.Page1.Data, 36);
if (nFreeList == 0)
return RC.DONE;
var rc = pBt.ptrmapGet( iLastPg, ref eType, ref iPtrPage);
if (rc != RC.OK)
return rc;
if (eType == PTRMAP.ROOTPAGE)
return SysEx.SQLITE_CORRUPT_BKPT();
if (eType == PTRMAP.FREEPAGE)
{
if (nFin == 0)
{
// Remove the page from the files free-list. This is not required if nFin is non-zero. In that case, the free-list will be
// truncated to zero after this function returns, so it doesn't matter if it still contains some garbage entries.
Pgno iFreePg = 0;
var pFreePg = new MemPage();
rc = pBt.allocateBtreePage( ref pFreePg, ref iFreePg, iLastPg, 1);
if (rc != RC.OK)
return rc;
Debug.Assert(iFreePg == iLastPg);
pFreePg.releasePage();
}
}
else
{
Pgno iFreePg = 0; // Index of free page to move pLastPg to
var pLastPg = new MemPage();
rc = pBt.btreeGetPage( iLastPg, ref pLastPg, 0);
if (rc != RC.OK)
return rc;
// If nFin is zero, this loop runs exactly once and page pLastPg is swapped with the first free page pulled off the free list.
// On the other hand, if nFin is greater than zero, then keep looping until a free-page located within the first nFin pages of the file is found.
do
{
var pFreePg = new MemPage();
rc = pBt.allocateBtreePage(ref pFreePg, ref iFreePg, 0, 0);
if (rc != RC.OK)
{
pLastPg.releasePage();
return rc;
}
pFreePg.releasePage();
} while (nFin != 0 && iFreePg > nFin);
Debug.Assert(iFreePg < iLastPg);
rc = Pager.Write(pLastPg.DbPage);
if (rc == RC.OK)
rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg, (nFin != 0) ? 1 : 0);
pLastPg.releasePage();
if (rc != RC.OK)
return rc;
}
}
if (nFin == 0)
{
iLastPg--;
while (iLastPg == PENDING_BYTE_PAGE(pBt) || PTRMAP_ISPAGE(pBt, iLastPg))
{
if (PTRMAP_ISPAGE(pBt, iLastPg))
{
var pPg = new MemPage();
var rc = pBt.btreeGetPage(iLastPg, ref pPg, 0);
if (rc != RC.OK)
return rc;
rc = Pager.Write(pPg.DbPage);
pPg.releasePage();
if (rc != RC.OK)
return rc;
}
iLastPg--;
}
pBt.Pager.TruncateImage(iLastPg);
pBt.Pages = iLastPg;
}
return RC.OK;
}
internal RC lockBtree()
{
Debug.Assert(MutexEx.Held(this.Mutex));
Debug.Assert(this.Page1 == null);
var rc = this.Pager.SharedLock();
if (rc != RC.OK)
{
return(rc);
}
MemPage pPage1 = null; // Page 1 of the database file
rc = btreeGetPage(1, ref pPage1, 0);
if (rc != RC.OK)
{
return(rc);
}
// Do some checking to help insure the file we opened really is a valid database file.
Pgno nPageHeader; // Number of pages in the database according to hdr
var nPage = nPageHeader = ConvertEx.Get4(pPage1.Data, 28); // Number of pages in the database
Pgno nPageFile; // Number of pages in the database file
this.Pager.GetPageCount(out nPageFile);
if (nPage == 0 || ArrayEx.Compare(pPage1.Data, 24, pPage1.Data, 92, 4) != 0)
{
nPage = nPageFile;
}
if (nPage > 0)
{
var page1 = pPage1.Data;
rc = RC.NOTADB;
if (ArrayEx.Compare(page1, Btree.zMagicHeader, 16) != 0)
{
goto page1_init_failed;
}
#if SQLITE_OMIT_WAL
if (page1[18] > 1)
{
this.ReadOnly = true;
}
if (page1[19] > 1)
{
this.Schema.file_format = page1[19];
goto page1_init_failed;
}
#else
if (page1[18] > 2)
{
pBt.readOnly = true;
}
if (page1[19] > 2)
{
goto page1_init_failed;
}
/* If the write version is set to 2, this database should be accessed
** in WAL mode. If the log is not already open, open it now. Then
** return SQLITE_OK and return without populating BtShared.pPage1.
** The caller detects this and calls this function again. This is
** required as the version of page 1 currently in the page1 buffer
** may not be the latest version - there may be a newer one in the log
** file.
*/
if (page1[19] == 2 && pBt.doNotUseWAL == false)
{
int isOpen = 0;
rc = sqlite3PagerOpenWal(pBt.pPager, ref isOpen);
if (rc != SQLITE_OK)
{
goto page1_init_failed;
}
else if (isOpen == 0)
{
releasePage(pPage1);
return(SQLITE_OK);
}
rc = SQLITE_NOTADB;
}
#endif
// The maximum embedded fraction must be exactly 25%. And the minimum embedded fraction must be 12.5% for both leaf-data and non-leaf-data.
// The original design allowed these amounts to vary, but as of version 3.6.0, we require them to be fixed.
if (ArrayEx.Compare(page1, 21, "\x0040\x0020\x0020", 3) != 0) // "\100\040\040"
{
goto page1_init_failed;
}
var pageSize = (uint)((page1[16] << 8) | (page1[17] << 16));
if (((pageSize - 1) & pageSize) != 0 || pageSize > Pager.SQLITE_MAX_PAGE_SIZE || pageSize <= 256)
{
goto page1_init_failed;
}
Debug.Assert((pageSize & 7) == 0);
var usableSize = pageSize - page1[20];
if (pageSize != this.PageSize)
{
// After reading the first page of the database assuming a page size of BtShared.pageSize, we have discovered that the page-size is
// actually pageSize. Unlock the database, leave pBt.pPage1 at zero and return SQLITE_OK. The caller will call this function
// again with the correct page-size.
pPage1.releasePage();
this.UsableSize = usableSize;
this.PageSize = pageSize;
rc = this.Pager.SetPageSize(ref this.PageSize, (int)(pageSize - usableSize));
return(rc);
}
if ((this.DB.flags & sqlite3b.SQLITE.RecoveryMode) == 0 && nPage > nPageFile)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto page1_init_failed;
}
if (usableSize < 480)
{
goto page1_init_failed;
}
this.PageSize = pageSize;
this.UsableSize = usableSize;
#if !SQLITE_OMIT_AUTOVACUUM
this.AutoVacuum = (ConvertEx.Get4(page1, 36 + 4 * 4) != 0);
this.IncrVacuum = (ConvertEx.Get4(page1, 36 + 7 * 4) != 0);
#endif
}
// maxLocal is the maximum amount of payload to store locally for a cell. Make sure it is small enough so that at least minFanout
// cells can will fit on one page. We assume a 10-byte page header. Besides the payload, the cell must store:
// 2-byte pointer to the cell
// 4-byte child pointer
// 9-byte nKey value
// 4-byte nData value
// 4-byte overflow page pointer
// So a cell consists of a 2-byte pointer, a header which is as much as 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow page pointer.
this.MaxLocal = (ushort)((this.UsableSize - 12) * 64 / 255 - 23);
this.MinLocal = (ushort)((this.UsableSize - 12) * 32 / 255 - 23);
this.MaxLeaf = (ushort)(this.UsableSize - 35);
this.MinLeaf = (ushort)((this.UsableSize - 12) * 32 / 255 - 23);
Debug.Assert(this.MaxLeaf + 23 <= Btree.MX_CELL_SIZE(this));
this.Page1 = pPage1;
this.Pages = nPage;
return(RC.OK);
page1_init_failed:
pPage1.releasePage();
this.Page1 = null;
return(rc);
}
internal RC allocateBtreePage(ref MemPage ppPage, ref Pgno pPgno, Pgno nearby, byte exact)
{
MemPage pTrunk = null;
MemPage pPrevTrunk = null;
Debug.Assert(MutexEx.Held(this.Mutex));
var pPage1 = this.Page1;
var mxPage = btreePagecount(); // Total size of the database file
var n = ConvertEx.Get4(pPage1.Data, 36); // Number of pages on the freelist
if (n >= mxPage)
return SysEx.SQLITE_CORRUPT_BKPT();
RC rc;
if (n > 0)
{
// There are pages on the freelist. Reuse one of those pages.
Pgno iTrunk;
byte searchList = 0; // If the free-list must be searched for 'nearby'
// If the 'exact' parameter was true and a query of the pointer-map shows that the page 'nearby' is somewhere on the free-list, then the entire-list will be searched for that page.
#if !SQLITE_OMIT_AUTOVACUUM
if (exact != 0 && nearby <= mxPage)
{
Debug.Assert(nearby > 0);
Debug.Assert(this.AutoVacuum);
PTRMAP eType = 0;
uint dummy0 = 0;
rc = ptrmapGet(nearby, ref eType, ref dummy0);
if (rc != RC.OK)
return rc;
if (eType == PTRMAP.FREEPAGE)
searchList = 1;
pPgno = nearby;
}
#endif
// Decrement the free-list count by 1. Set iTrunk to the index of the first free-list trunk page. iPrevTrunk is initially 1.
rc = Pager.Write(pPage1.DbPage);
if (rc != RC.OK)
return rc;
ConvertEx.Put4(pPage1.Data, 36, n - 1);
// The code within this loop is run only once if the 'searchList' variable is not true. Otherwise, it runs once for each trunk-page on the
// free-list until the page 'nearby' is located.
do
{
pPrevTrunk = pTrunk;
iTrunk = (pPrevTrunk != null ? ConvertEx.Get4(pPrevTrunk.Data, 0) : ConvertEx.Get4(pPage1.Data, 32));
rc = (iTrunk > mxPage ? SysEx.SQLITE_CORRUPT_BKPT() : btreeGetPage(iTrunk, ref pTrunk, 0));
if (rc != RC.OK)
{
pTrunk = null;
goto end_allocate_page;
}
var k = ConvertEx.Get4(pTrunk.Data, 4); // # of leaves on this trunk page
if (k == 0 && searchList == 0)
{
// The trunk has no leaves and the list is not being searched. So extract the trunk page itself and use it as the newly allocated page
Debug.Assert(pPrevTrunk == null);
rc = Pager.Write(pTrunk.DbPage);
if (rc != RC.OK)
goto end_allocate_page;
pPgno = iTrunk;
Buffer.BlockCopy(pTrunk.Data, 0, pPage1.Data, 32, 4);
ppPage = pTrunk;
pTrunk = null;
Btree.TRACE("ALLOCATE: %d trunk - %d free pages left\n", pPgno, n - 1);
}
else if (k > (uint)(this.UsableSize / 4 - 2))
{
// Value of k is out of range. Database corruption
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
#if !SQLITE_OMIT_AUTOVACUUM
}
else if (searchList != 0 && nearby == iTrunk)
{
// The list is being searched and this trunk page is the page to allocate, regardless of whether it has leaves.
Debug.Assert(pPgno == iTrunk);
ppPage = pTrunk;
searchList = 0;
rc = Pager.Write(pTrunk.DbPage);
if (rc != RC.OK)
goto end_allocate_page;
if (k == 0)
{
if (pPrevTrunk == null)
{
pPage1.Data[32 + 0] = pTrunk.Data[0 + 0];
pPage1.Data[32 + 1] = pTrunk.Data[0 + 1];
pPage1.Data[32 + 2] = pTrunk.Data[0 + 2];
pPage1.Data[32 + 3] = pTrunk.Data[0 + 3];
}
else
{
rc = Pager.Write(pPrevTrunk.DbPage);
if (rc != RC.OK)
goto end_allocate_page;
pPrevTrunk.Data[0 + 0] = pTrunk.Data[0 + 0];
pPrevTrunk.Data[0 + 1] = pTrunk.Data[0 + 1];
pPrevTrunk.Data[0 + 2] = pTrunk.Data[0 + 2];
pPrevTrunk.Data[0 + 3] = pTrunk.Data[0 + 3];
}
}
else
{
// The trunk page is required by the caller but it contains pointers to free-list leaves. The first leaf becomes a trunk page in this case.
var pNewTrunk = new MemPage();
var iNewTrunk = (Pgno)ConvertEx.Get4(pTrunk.Data, 8);
if (iNewTrunk > mxPage)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
}
rc = btreeGetPage(iNewTrunk, ref pNewTrunk, 0);
if (rc != RC.OK)
goto end_allocate_page;
rc = Pager.Write(pNewTrunk.DbPage);
if (rc != RC.OK)
{
pNewTrunk.releasePage();
goto end_allocate_page;
}
pNewTrunk.Data[0 + 0] = pTrunk.Data[0 + 0];
pNewTrunk.Data[0 + 1] = pTrunk.Data[0 + 1];
pNewTrunk.Data[0 + 2] = pTrunk.Data[0 + 2];
pNewTrunk.Data[0 + 3] = pTrunk.Data[0 + 3];
ConvertEx.Put4(pNewTrunk.Data, 4, (uint)(k - 1));
Buffer.BlockCopy(pTrunk.Data, 12, pNewTrunk.Data, 8, (int)(k - 1) * 4);
pNewTrunk.releasePage();
if (pPrevTrunk == null)
{
Debug.Assert(Pager.IsPageWriteable(pPage1.DbPage));
ConvertEx.Put4(pPage1.Data, 32, iNewTrunk);
}
else
{
rc = Pager.Write(pPrevTrunk.DbPage);
if (rc != RC.OK)
goto end_allocate_page;
ConvertEx.Put4(pPrevTrunk.Data, 0, iNewTrunk);
}
}
pTrunk = null;
Btree.TRACE("ALLOCATE: %d trunk - %d free pages left\n", pPgno, n - 1);
#endif
}
else if (k > 0)
{
// Extract a leaf from the trunk
uint closest;
var aData = pTrunk.Data;
if (nearby > 0)
{
closest = 0;
var dist = Math.Abs((int)(ConvertEx.Get4(aData, 8) - nearby));
for (uint i = 1; i < k; i++)
{
int dist2 = Math.Abs((int)(ConvertEx.Get4(aData, 8 + i * 4) - nearby));
if (dist2 < dist)
{
closest = i;
dist = dist2;
}
}
}
else
closest = 0;
//
var iPage = (Pgno)ConvertEx.Get4(aData, 8 + closest * 4);
if (iPage > mxPage)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
}
if (searchList == 0 || iPage == nearby)
{
pPgno = iPage;
Btree.TRACE("ALLOCATE: %d was leaf %d of %d on trunk %d" + ": %d more free pages\n", pPgno, closest + 1, k, pTrunk.ID, n - 1);
rc = Pager.Write(pTrunk.DbPage);
if (rc != RC.OK)
goto end_allocate_page;
if (closest < k - 1)
Buffer.BlockCopy(aData, (int)(4 + k * 4), aData, 8 + (int)closest * 4, 4);
ConvertEx.Put4(aData, 4, (k - 1));
var noContent = (!btreeGetHasContent(pPgno) ? 1 : 0);
rc = btreeGetPage(pPgno, ref ppPage, noContent);
if (rc == RC.OK)
{
rc = Pager.Write((ppPage).DbPage);
if (rc != RC.OK)
ppPage.releasePage();
}
searchList = 0;
}
}
pPrevTrunk.releasePage();
pPrevTrunk = null;
} while (searchList != 0);
}
else
{
// There are no pages on the freelist, so create a new page at the end of the file
rc = Pager.Write(this.Page1.DbPage);
if (rc != RC.OK)
return rc;
this.Pages++;
if (this.Pages == MemPage.PENDING_BYTE_PAGE(this))
this.Pages++;
#if !SQLITE_OMIT_AUTOVACUUM
if (this.AutoVacuum && MemPage.PTRMAP_ISPAGE(this, this.Pages))
{
// If pPgno refers to a pointer-map page, allocate two new pages at the end of the file instead of one. The first allocated page
// becomes a new pointer-map page, the second is used by the caller.
MemPage pPg = null;
Btree.TRACE("ALLOCATE: %d from end of file (pointer-map page)\n", pPgno);
Debug.Assert(this.Pages != MemPage.PENDING_BYTE_PAGE(this));
rc = btreeGetPage(this.Pages, ref pPg, 1);
if (rc == RC.OK)
{
rc = Pager.Write(pPg.DbPage);
pPg.releasePage();
}
if (rc != RC.OK)
return rc;
this.Pages++;
if (this.Pages == MemPage.PENDING_BYTE_PAGE(this))
this.Pages++;
}
#endif
ConvertEx.Put4(this.Page1.Data, 28, this.Pages);
pPgno = this.Pages;
Debug.Assert(pPgno != MemPage.PENDING_BYTE_PAGE(this));
rc = btreeGetPage(pPgno, ref ppPage, 1);
if (rc != RC.OK)
return rc;
rc = Pager.Write((ppPage).DbPage);
if (rc != RC.OK)
ppPage.releasePage();
Btree.TRACE("ALLOCATE: %d from end of file\n", pPgno);
}
Debug.Assert(pPgno != MemPage.PENDING_BYTE_PAGE(this));
end_allocate_page:
pTrunk.releasePage();
pPrevTrunk.releasePage();
if (rc == RC.OK)
{
if (Pager.GetPageRefCount((ppPage).DbPage) > 1)
{
ppPage.releasePage();
return SysEx.SQLITE_CORRUPT_BKPT();
}
(ppPage).HasInit = false;
}
else
ppPage = null;
Debug.Assert(rc != RC.OK || Pager.IsPageWriteable((ppPage).DbPage));
return rc;
}
internal RC getAndInitPage(Pgno pgno, ref MemPage ppPage)
{
Debug.Assert(MutexEx.Held(this.Mutex));
RC rc;
if (pgno > btreePagecount())
rc = SysEx.SQLITE_CORRUPT_BKPT();
else
{
rc = btreeGetPage(pgno, ref ppPage, 0);
if (rc == RC.OK)
{
rc = ppPage.btreeInitPage();
if (rc != RC.OK)
ppPage.releasePage();
}
}
Debug.Assert(pgno != 0 || rc == RC.CORRUPT);
return rc;
}
static int NB = (NN * 2 + 1); // Total pages involved in the balance
#if !SQLITE_OMIT_QUICKBALANCE
internal static RC balance_quick(MemPage parentPage, MemPage page, byte[] space)
{
Debug.Assert(MutexEx.Held(page.Shared.Mutex));
Debug.Assert(Pager.IsPageWriteable(parentPage.DbPage));
Debug.Assert(page.NOverflows == 1);
// This error condition is now caught prior to reaching this function
if (page.Cells <= 0)
{
return(SysEx.SQLITE_CORRUPT_BKPT());
}
// Allocate a new page. This page will become the right-sibling of pPage. Make the parent page writable, so that the new divider cell
// may be inserted. If both these operations are successful, proceed.
var shared = page.Shared; // B-Tree Database
var newPage = new MemPage(); // Newly allocated page
Pgno pgnoNew = 0; // Page number of pNew
var rc = shared.allocateBtreePage(ref newPage, ref pgnoNew, 0, 0);
if (rc != RC.OK)
{
return(rc);
}
var pOut = 4;
var pCell = page.Overflows[0].Cell;
var szCell = new int[1] {
page.cellSizePtr(pCell)
};
Debug.Assert(Pager.IsPageWriteable(newPage.DbPage));
Debug.Assert(page.Data[0] == (Btree.PTF_INTKEY | Btree.PTF_LEAFDATA | Btree.PTF_LEAF));
newPage.zeroPage(Btree.PTF_INTKEY | Btree.PTF_LEAFDATA | Btree.PTF_LEAF);
newPage.assemblePage(1, pCell, szCell);
// If this is an auto-vacuum database, update the pointer map with entries for the new page, and any pointer from the
// cell on the page to an overflow page. If either of these operations fails, the return code is set, but the contents
// of the parent page are still manipulated by thh code below. That is Ok, at this point the parent page is guaranteed to
// be marked as dirty. Returning an error code will cause a rollback, undoing any changes made to the parent page.
#if !SQLITE_OMIT_AUTOVACUUM
if (shared.AutoVacuum)
#else
if (false)
#endif
{
shared.ptrmapPut(pgnoNew, PTRMAP.BTREE, parentPage.ID, ref rc);
if (szCell[0] > newPage.MinLocal)
{
newPage.ptrmapPutOvflPtr(pCell, ref rc);
}
}
// Create a divider cell to insert into pParent. The divider cell consists of a 4-byte page number (the page number of pPage) and
// a variable length key value (which must be the same value as the largest key on pPage).
// To find the largest key value on pPage, first find the right-most cell on pPage. The first two fields of this cell are the
// record-length (a variable length integer at most 32-bits in size) and the key value (a variable length integer, may have any value).
// The first of the while(...) loops below skips over the record-length field. The second while(...) loop copies the key value from the
// cell on pPage into the pSpace buffer.
var iCell = page.FindCell(page.Cells - 1);
pCell = page.Data;
var _pCell = iCell;
var pStop = _pCell + 9;
while (((pCell[_pCell++]) & 0x80) != 0 && _pCell < pStop)
{
;
}
pStop = _pCell + 9;
while (((space[pOut++] = pCell[_pCell++]) & 0x80) != 0 && _pCell < pStop)
{
;
}
// Insert the new divider cell into pParent.
parentPage.insertCell(parentPage.Cells, space, pOut, null, page.ID, ref rc);
// Set the right-child pointer of pParent to point to the new page.
ConvertEx.Put4L(parentPage.Data, parentPage.HeaderOffset + 8, pgnoNew);
// Release the reference to the new page.
newPage.releasePage();
return(rc);
}
internal RC btreeCreateTable(ref int piTable, CREATETABLE createTabFlags)
{
var pBt = this.Shared;
var pRoot = new MemPage();
Pgno pgnoRoot = 0;
int ptfFlags; // Page-type flage for the root page of new table
RC rc;
Debug.Assert(sqlite3BtreeHoldsMutex());
Debug.Assert(pBt.InTransaction == TRANS.WRITE);
Debug.Assert(!pBt.ReadOnly);
#if SQLITE_OMIT_AUTOVACUUM
rc = allocateBtreePage(pBt, ref pRoot, ref pgnoRoot, 1, 0);
if (rc != SQLITE.OK)
{
return(rc);
}
#else
if (pBt.AutoVacuum)
{
Pgno pgnoMove = 0; // Move a page here to make room for the root-page
var pPageMove = new MemPage(); // The page to move to.
// Creating a new table may probably require moving an existing database to make room for the new tables root page. In case this page turns
// out to be an overflow page, delete all overflow page-map caches held by open cursors.
invalidateAllOverflowCache(pBt);
// Read the value of meta[3] from the database to determine where the root page of the new table should go. meta[3] is the largest root-page
// created so far, so the new root-page is (meta[3]+1).
GetMeta((int)META.LARGEST_ROOT_PAGE, ref pgnoRoot);
pgnoRoot++;
// The new root-page may not be allocated on a pointer-map page, or the PENDING_BYTE page.
while (pgnoRoot == MemPage.PTRMAP_PAGENO(pBt, pgnoRoot) || pgnoRoot == MemPage.PENDING_BYTE_PAGE(pBt))
{
pgnoRoot++;
}
Debug.Assert(pgnoRoot >= 3);
// Allocate a page. The page that currently resides at pgnoRoot will be moved to the allocated page (unless the allocated page happens to reside at pgnoRoot).
rc = pBt.allocateBtreePage(ref pPageMove, ref pgnoMove, pgnoRoot, 1);
if (rc != RC.OK)
{
return(rc);
}
if (pgnoMove != pgnoRoot)
{
// pgnoRoot is the page that will be used for the root-page of the new table (assuming an error did not occur). But we were
// allocated pgnoMove. If required (i.e. if it was not allocated by extending the file), the current page at position pgnoMove
// is already journaled.
PTRMAP eType = 0;
Pgno iPtrPage = 0;
pPageMove.releasePage();
// Move the page currently at pgnoRoot to pgnoMove.
rc = pBt.btreeGetPage(pgnoRoot, ref pRoot, 0);
if (rc != RC.OK)
{
return(rc);
}
rc = pBt.ptrmapGet(pgnoRoot, ref eType, ref iPtrPage);
if (eType == PTRMAP.ROOTPAGE || eType == PTRMAP.FREEPAGE)
{
rc = SysEx.SQLITE_CORRUPT_BKPT();
}
if (rc != RC.OK)
{
pRoot.releasePage();
return(rc);
}
Debug.Assert(eType != PTRMAP.ROOTPAGE);
Debug.Assert(eType != PTRMAP.FREEPAGE);
rc = MemPage.relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
pRoot.releasePage();
// Obtain the page at pgnoRoot
if (rc != RC.OK)
{
return(rc);
}
rc = pBt.btreeGetPage(pgnoRoot, ref pRoot, 0);
if (rc != RC.OK)
{
return(rc);
}
rc = Pager.Write(pRoot.DbPage);
if (rc != RC.OK)
{
pRoot.releasePage();
return(rc);
}
}
else
{
pRoot = pPageMove;
}
// Update the pointer-map and meta-data with the new root-page number.
pBt.ptrmapPut(pgnoRoot, PTRMAP.ROOTPAGE, 0, ref rc);
if (rc != RC.OK)
{
pRoot.releasePage();
return(rc);
}
// When the new root page was allocated, page 1 was made writable in order either to increase the database filesize, or to decrement the
// freelist count. Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
Debug.Assert(Pager.IsPageWriteable(pBt.Page1.DbPage));
rc = SetMeta(4, pgnoRoot);
if (Check.NEVER(rc != RC.OK))
{
pRoot.releasePage();
return(rc);
}
}
else
{
rc = pBt.allocateBtreePage(ref pRoot, ref pgnoRoot, 1, 0);
if (rc != RC.OK)
{
return(rc);
}
}
#endif
Debug.Assert(Pager.IsPageWriteable(pRoot.DbPage));
ptfFlags = ((createTabFlags & CREATETABLE.INTKEY) != 0 ? PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF : PTF_ZERODATA | PTF_LEAF);
pRoot.zeroPage(ptfFlags);
Pager.Unref(pRoot.DbPage);
Debug.Assert((pBt.OpenFlags & OPEN.SINGLE) == 0 || pgnoRoot == 2);
piTable = (int)pgnoRoot;
return(RC.OK);
}
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 RC btreeCreateTable(ref int piTable, CREATETABLE createTabFlags)
{
var pBt = this.Shared;
var pRoot = new MemPage();
Pgno pgnoRoot = 0;
int ptfFlags; // Page-type flage for the root page of new table
RC rc;
Debug.Assert(sqlite3BtreeHoldsMutex());
Debug.Assert(pBt.InTransaction == TRANS.WRITE);
Debug.Assert(!pBt.ReadOnly);
#if SQLITE_OMIT_AUTOVACUUM
rc = allocateBtreePage(pBt, ref pRoot, ref pgnoRoot, 1, 0);
if (rc != SQLITE.OK)
return rc;
#else
if (pBt.AutoVacuum)
{
Pgno pgnoMove = 0; // Move a page here to make room for the root-page
var pPageMove = new MemPage(); // The page to move to.
// Creating a new table may probably require moving an existing database to make room for the new tables root page. In case this page turns
// out to be an overflow page, delete all overflow page-map caches held by open cursors.
invalidateAllOverflowCache(pBt);
// Read the value of meta[3] from the database to determine where the root page of the new table should go. meta[3] is the largest root-page
// created so far, so the new root-page is (meta[3]+1).
GetMeta((int)META.LARGEST_ROOT_PAGE, ref pgnoRoot);
pgnoRoot++;
// The new root-page may not be allocated on a pointer-map page, or the PENDING_BYTE page.
while (pgnoRoot == MemPage.PTRMAP_PAGENO(pBt, pgnoRoot) || pgnoRoot == MemPage.PENDING_BYTE_PAGE(pBt))
pgnoRoot++;
Debug.Assert(pgnoRoot >= 3);
// Allocate a page. The page that currently resides at pgnoRoot will be moved to the allocated page (unless the allocated page happens to reside at pgnoRoot).
rc = pBt.allocateBtreePage(ref pPageMove, ref pgnoMove, pgnoRoot, 1);
if (rc != RC.OK)
return rc;
if (pgnoMove != pgnoRoot)
{
// pgnoRoot is the page that will be used for the root-page of the new table (assuming an error did not occur). But we were
// allocated pgnoMove. If required (i.e. if it was not allocated by extending the file), the current page at position pgnoMove
// is already journaled.
PTRMAP eType = 0;
Pgno iPtrPage = 0;
pPageMove.releasePage();
// Move the page currently at pgnoRoot to pgnoMove.
rc = pBt.btreeGetPage(pgnoRoot, ref pRoot, 0);
if (rc != RC.OK)
return rc;
rc = pBt.ptrmapGet(pgnoRoot, ref eType, ref iPtrPage);
if (eType == PTRMAP.ROOTPAGE || eType == PTRMAP.FREEPAGE)
rc = SysEx.SQLITE_CORRUPT_BKPT();
if (rc != RC.OK)
{
pRoot.releasePage();
return rc;
}
Debug.Assert(eType != PTRMAP.ROOTPAGE);
Debug.Assert(eType != PTRMAP.FREEPAGE);
rc = MemPage.relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
pRoot.releasePage();
// Obtain the page at pgnoRoot
if (rc != RC.OK)
return rc;
rc = pBt.btreeGetPage(pgnoRoot, ref pRoot, 0);
if (rc != RC.OK)
return rc;
rc = Pager.Write(pRoot.DbPage);
if (rc != RC.OK)
{
pRoot.releasePage();
return rc;
}
}
else
pRoot = pPageMove;
// Update the pointer-map and meta-data with the new root-page number.
pBt.ptrmapPut(pgnoRoot, PTRMAP.ROOTPAGE, 0, ref rc);
if (rc != RC.OK)
{
pRoot.releasePage();
return rc;
}
// When the new root page was allocated, page 1 was made writable in order either to increase the database filesize, or to decrement the
// freelist count. Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
Debug.Assert(Pager.IsPageWriteable(pBt.Page1.DbPage));
rc = SetMeta(4, pgnoRoot);
if (Check.NEVER(rc != RC.OK))
{
pRoot.releasePage();
return rc;
}
}
else
{
rc = pBt.allocateBtreePage(ref pRoot, ref pgnoRoot, 1, 0);
if (rc != RC.OK)
return rc;
}
#endif
Debug.Assert(Pager.IsPageWriteable(pRoot.DbPage));
ptfFlags = ((createTabFlags & CREATETABLE.INTKEY) != 0 ? PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF : PTF_ZERODATA | PTF_LEAF);
pRoot.zeroPage(ptfFlags);
Pager.Unref(pRoot.DbPage);
Debug.Assert((pBt.OpenFlags & OPEN.SINGLE) == 0 || pgnoRoot == 2);
piTable = (int)pgnoRoot;
return RC.OK;
}
