public WriteRaw ( long position, byte buffer, int length ) : void | ||
position | long | The starting position |
buffer | byte | the byte buffer of data to write |
length | int | the number of bytes to write |
return | void |
/// <summary> /// Creates a file backed memory stream. /// </summary> /// <param name="stream">The <see cref="CustomFileStream"/> to buffer</param> /// <param name="pool">The <see cref="MemoryPool"/> to allocate memory from</param> /// <param name="header">The <see cref="FileHeaderBlock"/> to be managed when modifications occur</param> /// <param name="isNewFile">Tells if this is a newly created file. This will make sure that the /// first 10 pages have the header data copied to it.</param> public BufferedFile(CustomFileStream stream, MemoryPool pool, FileHeaderBlock header, bool isNewFile) { m_fileStructureBlockSize = header.BlockSize; m_diskBlockSize = pool.PageSize; m_lengthOfHeader = header.BlockSize * header.HeaderBlockCount; m_writeBuffer = new MemoryPoolStreamCore(pool); m_pool = pool; m_queue = stream; m_syncRoot = new object(); m_pageReplacementAlgorithm = new PageReplacementAlgorithm(pool); pool.RequestCollection += m_pool_RequestCollection; if (isNewFile) { try { m_queue.Open(); byte[] headerBytes = header.GetBytes(); for (int x = 0; x < header.HeaderBlockCount; x++) { m_queue.WriteRaw(0, headerBytes, headerBytes.Length); } } finally { m_queue.Close(); } } m_lengthOfCommittedData = (header.LastAllocatedBlock + 1) * header.BlockSize; m_writeBuffer.ConfigureAlignment(m_lengthOfCommittedData, pool.PageSize); }
/// <summary> /// Executes a commit of data. This will flush the data to the disk use the provided header data to properly /// execute this function. /// </summary> /// <param name="header"></param> public void CommitChanges(FileHeaderBlock header) { using (var pageLock = new IoSession(this, m_pageReplacementAlgorithm)) { //Determine how much committed data to write long lengthOfAllData = (header.LastAllocatedBlock + 1) * (long)m_fileStructureBlockSize; long copyLength = lengthOfAllData - m_lengthOfCommittedData; //Write the uncommitted data. m_queue.Write(m_lengthOfCommittedData, m_writeBuffer, copyLength, waitForWriteToDisk: true); byte[] bytes = header.GetBytes(); if (header.HeaderBlockCount == 10) { //Update the new header to position 0, position 1, and one of position 2-9 m_queue.WriteRaw(0, bytes, m_fileStructureBlockSize); m_queue.WriteRaw(m_fileStructureBlockSize, bytes, m_fileStructureBlockSize); m_queue.WriteRaw(m_fileStructureBlockSize * ((header.SnapshotSequenceNumber & 7) + 2), bytes, m_fileStructureBlockSize); } else { for (int x = 0; x < header.HeaderBlockCount; x++) { m_queue.WriteRaw(x * m_fileStructureBlockSize, bytes, m_fileStructureBlockSize); } } m_queue.FlushFileBuffers(); long startPos; //Copy recently committed data to the buffer pool if ((m_lengthOfCommittedData & (m_diskBlockSize - 1)) != 0) //Only if there is a split page. { startPos = m_lengthOfCommittedData & (~(long)(m_diskBlockSize - 1)); //Finish filling up the split page in the buffer. IntPtr ptrDest; if (pageLock.TryGetSubPage(startPos, out ptrDest)) { int length; IntPtr ptrSrc; m_writeBuffer.ReadBlock(m_lengthOfCommittedData, out ptrSrc, out length); Footer.WriteChecksumResultsToFooter(ptrSrc, m_fileStructureBlockSize, length); ptrDest += (m_diskBlockSize - length); Memory.Copy(ptrSrc, ptrDest, length); } startPos += m_diskBlockSize; } else { startPos = m_lengthOfCommittedData; } while (startPos < lengthOfAllData) { //If the address doesn't exist in the current list. Read it from the disk. int poolPageIndex; IntPtr poolAddress; m_pool.AllocatePage(out poolPageIndex, out poolAddress); m_writeBuffer.CopyTo(startPos, poolAddress, m_diskBlockSize); Footer.WriteChecksumResultsToFooter(poolAddress, m_fileStructureBlockSize, m_diskBlockSize); if (!m_pageReplacementAlgorithm.TryAddPage(startPos, poolAddress, poolPageIndex)) { m_pool.ReleasePage(poolPageIndex); } startPos += m_diskBlockSize; } m_lengthOfCommittedData = lengthOfAllData; } ReleaseWriteBufferSpace(); }
/// <summary> /// Creates a file backed memory stream. /// </summary> /// <param name="stream">The <see cref="CustomFileStream"/> to buffer</param> /// <param name="pool">The <see cref="MemoryPool"/> to allocate memory from</param> /// <param name="header">The <see cref="FileHeaderBlock"/> to be managed when modifications occur</param> /// <param name="isNewFile">Tells if this is a newly created file. This will make sure that the /// first 10 pages have the header data copied to it.</param> public BufferedFile(CustomFileStream stream, MemoryPool pool, FileHeaderBlock header, bool isNewFile) { m_fileStructureBlockSize = header.BlockSize; m_diskBlockSize = pool.PageSize; m_lengthOfHeader = header.BlockSize * header.HeaderBlockCount; m_writeBuffer = new MemoryPoolStreamCore(pool); m_pool = pool; m_queue = stream; m_syncRoot = new object(); m_pageReplacementAlgorithm = new PageReplacementAlgorithm(pool); pool.RequestCollection += m_pool_RequestCollection; if (isNewFile) { byte[] headerBytes = header.GetBytes(); for (int x = 0; x < header.HeaderBlockCount; x++) { m_queue.WriteRaw(0, headerBytes, headerBytes.Length); } } m_lengthOfCommittedData = (header.LastAllocatedBlock + 1) * (long)header.BlockSize; m_writeBuffer.ConfigureAlignment(m_lengthOfCommittedData, pool.PageSize); }