private void ReadProc()
{
var lengthBuffer = new byte[4];
var dataBuffer = new byte[m_mmf.Length - 4];
while (true)
{
// use a timeout so if the app ends, this thread can exit
if (!m_dataReady.WaitOne(1000, false))
{
continue;
}
// avoid receiving our own data
if (Sending)
{
// wait long enough for the sender to reset the m_dataReady flag
Thread2.Sleep(5);
continue;
}
// grab the mutex to prevent concurrency issues
m_mutex.WaitOne(1000, false);
// read from the start
m_mmf.Seek(0, System.IO.SeekOrigin.Begin);
// get the length
m_mmf.Read(lengthBuffer, 0, 4);
var length = BitConverter.ToInt32(lengthBuffer, 0);
// get the data
m_mmf.Read(dataBuffer, 0, length);
// release the mutex so any other clients can receive
m_mutex.ReleaseMutex();
// convert to a string
var received = Encoding.ASCII.GetString(dataBuffer, 0, length);
Console.WriteLine("Received: " + received);
Debug.WriteLine("Received: " + received);
}
}
public void Run()
{
var processName = Path.GetFileNameWithoutExtension(Assembly.GetExecutingAssembly().GetName().CodeBase);
// create the MMF
m_mmf = MemoryMappedFile.CreateInMemoryMap(SharedMapName, MaxMapSize);
// create a shared mutex
m_mutex = new NamedMutex(false, SharedMutexName);
// create a data-ready event
m_dataReady = new EventWaitHandle(false, EventResetMode.ManualReset, DataReadyEventName);
// fire up a "listener"
new System.Threading.Thread(ReadProc)
{
IsBackground = true,
Name = "MMF Peer Reader"
}
.Start();
Console.WriteLine("Memory Mapped File Created. Enter text to send to peer(s)");
// wait for user input
while (true)
{
var input = Console.ReadLine();
if (input == null)
{
Thread2.Sleep(5000);
input = GetMockInput();
Debug.WriteLine(string.Format("Platform does not have a Console installed. Sending mock data '{0}'", input));
}
if (input == "exit")
{
break;
}
// prefix our process name so we can tell who sent the data
input = processName + ":" + input;
// grab the mutex
if (!m_mutex.WaitOne(5000, false))
{
Console.WriteLine("Unable to acquire mutex. Send Abandoned");
Debug.WriteLine("Unable to acquire mutex. Send Abandoned");
continue;
}
// mark as "sending" so the listener will ignore what we send
Sending = true;
// create a "packet" (length + data)
var packet = new byte[4 + input.Length];
Buffer.BlockCopy(BitConverter.GetBytes(input.Length), 0, packet, 0, 4);
Buffer.BlockCopy(Encoding.ASCII.GetBytes(input), 0, packet, 4, input.Length);
// write the packet at the start
m_mmf.Seek(0, System.IO.SeekOrigin.Begin);
m_mmf.Write(packet, 0, packet.Length);
// notify all clients that data is ready (manual reset events will release all waiting clients)
m_dataReady.Set();
// yield to allow the receiver to unblock and check the "Sending" flag
Thread2.Sleep(1);
// reset the event
m_dataReady.Reset();
// unmark "sending"
Sending = false;
// release the mutex
m_mutex.ReleaseMutex();
}
}