Beispiel #1
0
        /// <summary>
        /// Delete a single index node - fix tree double-linked list levels
        /// </summary>
        private void DeleteSingleNode(IndexNode node)
        {
            for (int i = node.Level - 1; i >= 0; i--)
            {
                // get previous and next nodes (between my deleted node)
                var prevNode = this.GetNode(node.Prev[i]);
                var nextNode = this.GetNode(node.Next[i]);

                if (prevNode != null)
                {
                    prevNode.SetNext((byte)i, node.Next[i]);
                }
                if (nextNode != null)
                {
                    nextNode.SetPrev((byte)i, node.Prev[i]);
                }
            }

            // get current slot position in free list
            var slot = BasePage.FreeIndexSlot(node.Page.FreeBytes);

            node.Page.DeleteIndexNode(node.Position.Index);

            // update (if needed) slot position
            _snapshot.AddOrRemoveFreeList(node.Page, slot);
        }
Beispiel #2
0
        /// <summary>
        /// Update document using same page position as reference
        /// </summary>
        public void Update(CollectionPage col, PageAddress blockAddress, BsonDocument doc)
        {
            var bytesLeft = doc.GetBytesCount(true);

            if (bytesLeft > MAX_DOCUMENT_SIZE)
            {
                throw new LiteException(0, "Document size exceed {0} limit", MAX_DOCUMENT_SIZE);
            }

            DataBlock lastBlock     = null;
            var       updateAddress = blockAddress;

            IEnumerable <BufferSlice> source()
            {
                var bytesToCopy = 0;

                while (bytesLeft > 0)
                {
                    // if last block contains new block sequence, continue updating
                    if (updateAddress.IsEmpty == false)
                    {
                        var dataPage     = _snapshot.GetPage <DataPage>(updateAddress.PageID);
                        var currentBlock = dataPage.GetBlock(updateAddress.Index);

                        // try get full page size content
                        bytesToCopy = Math.Min(bytesLeft, dataPage.FreeBytes + currentBlock.Buffer.Count);

                        // get current free slot linked list
                        var slot = BasePage.FreeIndexSlot(dataPage.FreeBytes);

                        var updateBlock = dataPage.UpdateBlock(currentBlock, bytesToCopy);

                        _snapshot.AddOrRemoveFreeList(dataPage, slot);

                        yield return(updateBlock.Buffer);

                        lastBlock = updateBlock;

                        // go to next address (if extits)
                        updateAddress = updateBlock.NextBlock;
                    }
                    else
                    {
                        bytesToCopy = Math.Min(bytesLeft, MAX_DATA_BYTES_PER_PAGE);
                        var dataPage    = _snapshot.GetFreePage <DataPage>(bytesToCopy + DataBlock.DATA_BLOCK_FIXED_SIZE);
                        var insertBlock = dataPage.InsertBlock(bytesToCopy, true);

                        if (lastBlock != null)
                        {
                            lastBlock.SetNextBlock(insertBlock.Position);
                        }

                        yield return(insertBlock.Buffer);

                        lastBlock = insertBlock;
                    }

                    bytesLeft -= bytesToCopy;
                }

                // old document was bigger than current, must delete extend blocks
                if (lastBlock.NextBlock.IsEmpty == false)
                {
                    this.Delete(lastBlock.NextBlock);
                }
            }

            // consume all source bytes to write BsonDocument direct into PageBuffer
            // must be fastest as possible
            using (var w = new BufferWriter(source()))
            {
                // already bytes count calculate at method start
                w.WriteDocument(doc, false);
                w.Consume();
            }
        }