/// <summary>
/// Writes a message file.
/// </summary>
/// <param name="path">The file path.</param>
/// <param name="msg">The message.</param>
/// <param name="msgInfo">The message metadata.</param>
internal void WriteMessage(string path, QueuedMsg msg, QueuedMsgInfo msgInfo)
{
byte[] md5Hash;
using (var fsMsg = new EnhancedFileStream(path, FileMode.Create, FileAccess.ReadWrite))
{
// Write the file header
fsMsg.WriteInt32(MsgMagic); // Magic Number
fsMsg.WriteInt32(0); // Format Version
fsMsg.WriteInt32(0); // Reserved
fsMsg.WriteBytesNoLen(md5Zeros); // MD5 hash placeholder
// Write the message body.
fsMsg.WriteBytes32(msg.BodyRaw);
// Write the metadata.
fsMsg.WriteString16(msgInfo.ToString());
// Compute and save the MD5 hash
fsMsg.Position = MsgHeaderSize;
md5Hash = MD5Hasher.Compute(fsMsg, fsMsg.Length - fsMsg.Position);
fsMsg.Position = MsgMD5Offset;
fsMsg.WriteBytesNoLen(md5Hash);
}
}
/// <summary>
/// Updates a message file's metadata.
/// </summary>
/// <param name="path">The file path.</param>
/// <param name="msgInfo">The message metadata.</param>
internal void WriteMessageMetadata(string path, QueuedMsgInfo msgInfo)
{
using (var fsMsg = new EnhancedFileStream(path, FileMode.Open, FileAccess.ReadWrite))
{
// Seek past the message's header and body.
int cbBody;
byte[] md5Hash;
fsMsg.Position = MsgHeaderSize;
cbBody = fsMsg.ReadInt32();
fsMsg.Position = fsMsg.Position + cbBody;
// Write the metadata and truncate the file.
fsMsg.WriteString16(msgInfo.ToString());
fsMsg.SetLength(fsMsg.Position);
// Regenerate the MD5 Hash
fsMsg.Position = MsgMD5Offset + MD5Hasher.DigestSize;
md5Hash = MD5Hasher.Compute(fsMsg, fsMsg.Length - fsMsg.Position);
fsMsg.Position = MsgMD5Offset;
fsMsg.WriteBytesNoLen(md5Hash);
}
}
private void WriteFile(string path, byte[] data)
{
var es = new EnhancedFileStream(path, FileMode.Create);
es.WriteBytesNoLen(data);
es.Close();
}
private OperationLogMode mode; // The current mode
/// <summary>
/// Opens or creates a file operation log file.
/// </summary>
/// <param name="path">The path to the log file.</param>
/// <param name="transactionID">The log's transaction <see cref="Guid" />.</param>
/// <remarks>
/// New logs will be created in <see cref="OperationLogMode.Undo" /> mode.
/// </remarks>
public FileOperationLog(string path, Guid transactionID)
{
this.path = Path.GetFullPath(path);
this.file = new EnhancedFileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite);
if (file.Length == 0)
{
// Initialize a new file
file.WriteInt32(Magic);
file.WriteInt32(0);
file.WriteInt32(0);
file.WriteInt32((int)OperationLogMode.Undo);
file.WriteBytesNoLen(transactionID.ToByteArray());
file.Flush();
}
else
{
// Open an existing file.
try
{
if (file.ReadInt32() != Magic || // Magic number
file.ReadInt32() != 0)
{ // Format Versopn
throw new Exception();
}
file.ReadInt32(); // Reserved
switch (file.ReadInt32()) // Mode
{
case (int)OperationLogMode.Undo:
mode = OperationLogMode.Undo;
break;
case (int)OperationLogMode.Redo:
mode = OperationLogMode.Redo;
break;
default:
throw new Exception();
}
this.transactionID = new Guid(file.ReadBytes(16));
if (transactionID != this.transactionID)
{
throw new Exception();
}
}
catch
{
throw new TransactionException(CorruptMsg);
}
}
}