コード例 #1
0
        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);
        }
コード例 #2
0
        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();
            }
        }