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 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 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;
}
