public unsafe Page ModifyPage(Tree tree, Page parent, long p, Cursor c)
{
long dirtyPageNum;
Page page;
if (_dirtyPages.TryGetValue(p, out dirtyPageNum))
{
page = c.GetPage(dirtyPageNum) ?? _pager.Get(this, dirtyPageNum);
page.Dirty = true;
UpdateParentPageNumber(parent, page.PageNumber);
return(page);
}
var newPage = AllocatePage(1);
newPage.Dirty = true;
var newPageNum = newPage.PageNumber;
page = c.GetPage(p) ?? _pager.Get(this, p);
NativeMethods.memcpy(newPage.Base, page.Base, _pager.PageSize);
newPage.LastSearchPosition = page.LastSearchPosition;
newPage.LastMatch = page.LastMatch;
newPage.PageNumber = newPageNum;
FreePage(p);
_dirtyPages[p] = newPage.PageNumber;
UpdateParentPageNumber(parent, newPage.PageNumber);
return(newPage);
}
private void Setup(IVirtualPager pager)
{
if (pager.NumberOfAllocatedPages == 0)
{
WriteEmptyHeaderPage(_pager.Get(null, 0));
WriteEmptyHeaderPage(_pager.Get(null, 1));
NextPageNumber = 2;
using (var tx = new Transaction(_pager, this, _transactionsCounter + 1, TransactionFlags.ReadWrite, _freeSpaceRepository))
{
var root = Tree.Create(tx, _sliceComparer);
var freeSpace = Tree.Create(tx, _sliceComparer);
// important to first create the two trees, then set them on the env
FreeSpaceRoot = freeSpace;
Root = root;
tx.UpdateRoots(root, freeSpace);
tx.Commit();
}
return;
}
// existing db, let us load it
// the first two pages are allocated for double buffering tx commits
FileHeader *entry = FindLatestFileHeadeEntry();
NextPageNumber = entry->LastPageNumber + 1;
_transactionsCounter = entry->TransactionId + 1;
using (var tx = new Transaction(_pager, this, _transactionsCounter + 1, TransactionFlags.ReadWrite, _freeSpaceRepository))
{
var root = Tree.Open(tx, _sliceComparer, &entry->Root);
var freeSpace = Tree.Open(tx, _sliceComparer, &entry->FreeSpace);
// important to first create the two trees, then set them on the env
FreeSpaceRoot = freeSpace;
Root = root;
tx.Commit();
}
}