| 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);
}