/// <summary>
/// Flushes all the data in a named pipe.
/// </summary>
/// <param name="handle">The pipe handle.</param>
#endregion
public static void Flush(PipeHandle handle)
{
handle.State = InterProcessConnectionState.Flushing;
NamedPipeNative.FlushFileBuffers(handle.Handle);
handle.State = InterProcessConnectionState.FlushedData;
}
/// <summary>
/// Disconnects a server named pipe from the client.
/// </summary>
/// <remarks>
/// Server pipes can be reused by first disconnecting them from the client and then
/// calling the <see cref="AppModule.NamedPipes.NamedPipeWrapper.Connect">Connect</see>
/// method to start listening. This improves the performance as it is not necessary
/// to create new pipe handles.
/// </remarks>
/// <param name="handle">The pipe handle.</param>
#endregion
public static void Disconnect(PipeHandle handle)
{
handle.State = InterProcessConnectionState.Disconnecting;
NamedPipeNative.DisconnectNamedPipe(handle.Handle);
handle.State = InterProcessConnectionState.Disconnected;
}
/// <summary>
/// Returns the number of instances of a named pipe.
/// </summary>
/// <param name="handle">The pipe handle.</param>
/// <returns>The number of instances.</returns>
#endregion
public static uint NumberPipeInstances(PipeHandle handle)
{
uint curInstances = 0;
if (NamedPipeNative.GetNamedPipeHandleState(handle.Handle, IntPtr.Zero, ref curInstances, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero))
{
return(curInstances);
}
else
{
throw new NamedPipeIOException("Error getting the pipe state. Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
/// <summary>
/// Starts waiting for client connections.
/// </summary>
/// <remarks>
/// Blocks the current execution until a client pipe attempts to establish a connection.
/// </remarks>
/// <param name="handle">The pipe handle.</param>
#endregion
public static void Connect(PipeHandle handle)
{
handle.State = InterProcessConnectionState.WaitingForClient;
bool connected = NamedPipeNative.ConnectNamedPipe(handle.Handle, null);
handle.State = InterProcessConnectionState.ConnectedToClient;
if (!connected && NamedPipeNative.GetLastError() != NamedPipeNative.ERROR_PIPE_CONNECTED)
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Error connecting pipe. Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
/// <summary>
/// Creates a server named pipe.
/// </summary>
/// <param name="name">The name of the pipe.</param>
/// <param name="outBuffer">The size of the outbound buffer.</param>
/// <param name="inBuffer">The size of the inbound buffer.</param>
/// <returns>The pipe handle.</returns>
#endregion
public static PipeHandle Create(string name, uint outBuffer, uint inBuffer)
{
name = @"\\.\pipe\" + name;
PipeHandle handle = new PipeHandle();
for (int i = 1; i <= ATTEMPTS; i++)
{
handle.State = InterProcessConnectionState.Creating;
handle.Handle = NamedPipeNative.CreateNamedPipe(
name,
NamedPipeNative.PIPE_ACCESS_DUPLEX,
NamedPipeNative.PIPE_TYPE_MESSAGE | NamedPipeNative.PIPE_READMODE_MESSAGE | NamedPipeNative.PIPE_WAIT,
NamedPipeNative.PIPE_UNLIMITED_INSTANCES,
outBuffer,
inBuffer,
NamedPipeNative.NMPWAIT_WAIT_FOREVER,
IntPtr.Zero);
if (handle.Handle.ToInt32() != NamedPipeNative.INVALID_HANDLE_VALUE)
{
handle.State = InterProcessConnectionState.Created;
break;
}
if (i >= ATTEMPTS)
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Error creating named pipe " + name + " . Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
return(handle);
}
/// <summary>
/// Connects to a server named pipe.
/// </summary>
/// <param name="pipeName">The pipe name.</param>
/// <param name="serverName">The server name.</param>
/// <returns>The pipe handle, which also contains the pipe state.</returns>
/// <remarks>This method is used by clients to establish a pipe connection with a server pipe.</remarks>
#endregion
public static PipeHandle ConnectToPipe(string pipeName, string serverName)
{
PipeHandle handle = new PipeHandle();
// Build the name of the pipe.
string name = @"\\" + serverName + @"\pipe\" + pipeName;
for (int i = 1; i <= ATTEMPTS; i++)
{
handle.State = InterProcessConnectionState.ConnectingToServer;
// Try to connect to the server
handle.Handle = NamedPipeNative.CreateFile(name, NamedPipeNative.GENERIC_READ | NamedPipeNative.GENERIC_WRITE, 0, null, NamedPipeNative.OPEN_EXISTING, 0, 0);
if (handle.Handle.ToInt32() != NamedPipeNative.INVALID_HANDLE_VALUE)
{
// The client managed to connect to the server pipe
handle.State = InterProcessConnectionState.ConnectedToServer;
// Set the read mode of the pipe channel
uint mode = NamedPipeNative.PIPE_READMODE_MESSAGE;
if (NamedPipeNative.SetNamedPipeHandleState(handle.Handle, ref mode, IntPtr.Zero, IntPtr.Zero))
{
break;
}
if (i >= ATTEMPTS)
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Error setting read mode on pipe " + name + " . Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
if (i >= ATTEMPTS)
{
if (NamedPipeNative.GetLastError() != NamedPipeNative.ERROR_PIPE_BUSY)
{
handle.State = InterProcessConnectionState.Error;
// After a certain number of unsuccessful attempt raise an exception
throw new NamedPipeIOException("Error connecting to pipe " + name + " . Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
else
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Pipe " + name + " is too busy. Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
else
{
// The pipe is busy so lets wait for some time and try again
if (NamedPipeNative.GetLastError() == NamedPipeNative.ERROR_PIPE_BUSY)
{
NamedPipeNative.WaitNamedPipe(name, WAIT_TIME);
}
}
}
return(handle);
}
/// <summary>
/// Writes an array of bytes to a named pipe.
/// </summary>
/// <param name="handle">The pipe handle.</param>
/// <param name="bytes">The bytes to write.</param>
/// <remarks>If we try bytes array we attempt to write is empty then this method write a space character to the pipe. This is necessary because the other end of the pipe uses a blocking Read operation so we must write someting.<br/><br/>
/// The bytes length is restricted by the <b>maxBytes</b> parameter, which is done primarily for security reasons.<br/><br/>
/// When writing to a pipe the method first writes four bytes that define the data length.
/// It then writes the whole message.</remarks>
#endregion
public static void WriteBytes(PipeHandle handle, byte[] bytes)
{
byte[] numReadWritten = new byte[4];
uint len;
if (bytes == null)
{
bytes = new byte[0];
}
if (bytes.Length == 0)
{
bytes = new byte[1];
bytes = System.Text.Encoding.UTF8.GetBytes(" ");
}
// Get the message length
len = (uint)bytes.Length;
handle.State = InterProcessConnectionState.Writing;
// Write four bytes that define the message length
if (NamedPipeNative.WriteFile(handle.Handle, BitConverter.GetBytes(len), 4, numReadWritten, 0))
{
// Write the whole message
if (!NamedPipeNative.WriteFile(handle.Handle, bytes, len, numReadWritten, 0))
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Error writing to pipe. Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
else
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Error writing to pipe. Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
handle.State = InterProcessConnectionState.Flushing;
Flush(handle);
handle.State = InterProcessConnectionState.FlushedData;
}