/// <summary>
/// Instantiates MmfBufferedWriter.
/// </summary>
/// <param name="ipcType">Identifies memory mapped file and used to authenticate outgoing messages.</param>
/// <param name="bufferLength">Length of data segment</param>
/// <param name="ignoreExceptions">True if exceptions should be handled; false if they should be returned to the caller.</param>
public MmfBufferedWriter(string ipcType, int bufferLength, Niawa.Utilities.UtilsServiceBus utilsBus, bool ignoreExceptions)
{
try
{
_sendQueue = new Queue<NiawaMmfContainer>();
_header = new NiawaMmfBufferHeader();
_ipcType = ipcType;
_description = "MmfWriter " + _ipcType;
_bufferLength = bufferLength;
_ignoreExceptions = ignoreExceptions;
//initialize serial ID generator
id = utilsBus.InitializeSerialId(Niawa.Utilities.IdGeneratorUtils.ID_ROOT_NIAWA_MMF_CONTAINER);
//get random starting message ID
Random rnd = new Random();
int startingMsgID = rnd.Next(0, 100000);
_msgID = startingMsgID;
_threadStatus = new Niawa.Threading.ThreadStatus(_description, 60, utilsBus.InitializeSerialId(Niawa.Utilities.IdGeneratorUtils.ID_ROOT_NIAWA_THREAD_ID).ToString(), string.Empty, null);
//thread status
_threadStatus.Status = Niawa.Threading.ThreadStatus.STATUS_INITIALIZED;
}
catch (Exception ex)
{
logger.Error("[" + _description + "-M] Exception while instantiating: " + ex.Message, ex);
if (!ignoreExceptions)
throw ex;
}
}
/// <summary>
/// Initialize the buffer header file with empty values
/// </summary>
private void InitializeHeader()
{
try
{
//create a new buffer header
_header = new NiawaMmfBufferHeader();
SortedList<int, KeyValuePair<string, DateTime>> entries = new SortedList<int, KeyValuePair<string, DateTime>>();
//populate the buffer header with blank values
int ix = 1;
while (ix <= 100)
{
entries.Add(ix, new KeyValuePair<string, DateTime>(string.Empty, new DateTime(1900, 1, 1)));
ix++;
}
_header.Entries = entries;
_header.LatestUpdateDate = new DateTime(1900, 1, 1);
_header.LatestEntryID = 0;
//convert buffer header to bytes
byte[] buffer = _header.ToByteArray();
//locked section
using (new Niawa.Utilities.SingleGlobalInstance(1000, _ipcType + "_header")) //1000ms timeout on global lock
{
int msgLength = buffer.Length;
int msgID = 0;
//open mmf
MemoryMappedFile mmf = MemoryMappedFile.CreateOrOpen(_ipcType + "_header", _bufferLength);
MemoryMappedViewAccessor accessor1Len = mmf.CreateViewAccessor(0, 4);
MemoryMappedViewAccessor accessor2ID = mmf.CreateViewAccessor(8, 4);
MemoryMappedViewAccessor accessor3Data = mmf.CreateViewAccessor(16, msgLength);
//write data
accessor1Len.Write<Int32>(0, ref msgLength);
accessor2ID.Write<Int32>(0, ref msgID);
accessor3Data.WriteArray<byte>(0, buffer, 0, msgLength);
} //end locked section
}
catch (Exception ex)
{
logger.Error("[" + _description + "-M] Exception while initializing buffer header: " + ex.Message, ex);
if (!_ignoreExceptions)
throw ex;
}
}
private NiawaMmfBufferHeader InitializeCachedHeader(NiawaMmfBufferHeader cachedHeader)
{
try
{
//create a new buffer header
cachedHeader = new NiawaMmfBufferHeader();
SortedList<int, KeyValuePair<string, DateTime>> entries = new SortedList<int, KeyValuePair<string, DateTime>>();
//populate the buffer header with blank values
int ix = 1;
while (ix <= 100)
{
entries.Add(ix, new KeyValuePair<string, DateTime>(string.Empty, new DateTime(1900, 1, 1)));
ix++;
}
cachedHeader.Entries = entries;
cachedHeader.LatestUpdateDate = new DateTime(1900, 1, 1);
cachedHeader.LatestEntryID = 0;
return cachedHeader;
}
catch (Exception ex)
{
logger.Error("[" + _description + "-M] Exception while initializing buffer header: " + ex.Message, ex);
if (!_ignoreExceptions)
throw ex;
return null;
}
}
/// <summary>
/// Reads data from Mmf Header file into cached header object
/// </summary>
private bool ReadFromMmfHeaderFile()
{
/* Memory Mapped File:
* accessor1Len: bytes 0-4 total length of file
* accessor2ID: bytes 8-12 ID number of message
* accessor3Data: variable bytes payload
* */
int msgLength;
int msgID;
MemoryMappedFile mmf;
//System.Diagnostics.Debug.WriteLine("MmfBufferedReader [Header]: Filename " + _ipcType + "_header");
try
{
//open mmf
mmf = MemoryMappedFile.OpenExisting(_ipcType + "_header");
}
catch (System.IO.FileNotFoundException ex)
{
System.Diagnostics.Debug.WriteLine("MmfBufferedReader [" + _ipcType + "][Header]: Header file was not found");
throw ex;
}
MemoryMappedViewAccessor accessor1Len = mmf.CreateViewAccessor(0, 4);
MemoryMappedViewAccessor accessor2ID = mmf.CreateViewAccessor(8, 4);
MemoryMappedViewAccessor accessor3Data;
//locked section
using (new Niawa.Utilities.SingleGlobalInstance(1000, _ipcType)) //1000ms timeout on global lock
{
//get length, ID, and data
msgLength = accessor1Len.ReadInt32(0);
msgID = accessor2ID.ReadInt32(0);
accessor3Data = mmf.CreateViewAccessor(16, msgLength);
}
//System.Diagnostics.Debug.WriteLine("MmfBufferedReader [Header]: HeaderID:" + msgID);
//System.Diagnostics.Debug.WriteLine("MmfBufferedReader [Header]: LastHeaderID:" + _lastHeaderMsgID);
//check if ID changed
if (msgID == _lastHeaderMsgID)
{
//System.Diagnostics.Debug.WriteLine("MmfBufferedReader [Header]: There is no header work to do");
//do nothing
return false;
}
else
{
//System.Diagnostics.Debug.WriteLine("MmfBufferedReader [Header]: Reading header");
//set ID
_lastHeaderMsgID = msgID;
//get data
byte[] buffer = new byte[msgLength];
accessor3Data.ReadArray<byte>(0, buffer, 0, msgLength);
NiawaMmfBufferHeader msg = new NiawaMmfBufferHeader(buffer);
_previousCachedHeader = _cachedHeader;
_cachedHeader = msg;
return true;
}
}
/// <summary>
/// Start reading the memory mapped file in a loop thread.
/// </summary>
public void StartListening()
{
try
{
logger.Info("[" + _description + "-M] Starting");
if (_threadStatus.IsThreadEnabled)
{
logger.Warn("[" + _description + "-M] Could not start: Reader thread was already active");
}
else
{
//start thread
t1 = new System.Threading.Thread(ListenThreadImpl);
_receiveQueue.Clear();
_cachedHeader = InitializeCachedHeader(_cachedHeader);
_previousCachedHeader = InitializeCachedHeader(_previousCachedHeader);
_minimumMessageDate = DateTime.Now;
_threadStatus.IsThreadEnabled = true;
//start client
t1.Start();
//thread status
_threadStatus.Status = Niawa.Threading.ThreadStatus.STATUS_STARTED;
}
}
catch (Exception ex)
{
logger.Error("[" + _description + "-M] Exception during start listening: " + ex.Message, ex);
if (!_ignoreExceptions)
throw ex;
}
}
