/// <summary>
/// The Writequeue add a new Position to the Lock
/// </summary>
/// <param name="Position">The Physical Position on the storage</param>
public void Add(QueueEntry QueueEntry)
{
// this will work only if we have just 1 Stream and 1 Extent!!!
foreach (var ObjectExtent in QueueEntry.RWQueueStreams)
{
var WriteQueuePositions = new Dictionary<UInt64, Byte[]>();
lock (_Storages)
{
if (_Storages[ObjectExtent.StorageUUID] == null)
_Storages.Add(ObjectExtent.StorageUUID, WriteQueuePositions);
else
WriteQueuePositions = (Dictionary<UInt64, Byte[]>)_Storages[ObjectExtent.StorageUUID];
try
{
if (WriteQueuePositions.ContainsKey(ObjectExtent.PhysicalPosition))
{
// System.Diagnostics.Debug.WriteLine("[WriteCache]" + ObjectExtent.StorageID + "(" + WriteQueuePositions.Count + ") Overwrite " + ObjectExtent.PhysicalPosition + " Data: " + QueueEntry.Data.Length);
WriteQueuePositions[ObjectExtent.PhysicalPosition] = QueueEntry.Data;
}
else
{
// System.Diagnostics.Debug.WriteLine("[WriteCache]" + ObjectExtent.StorageID + "(" + WriteQueuePositions.Count + ") Add " + ObjectExtent.PhysicalPosition + " Data: " + QueueEntry.Data.Length);
WriteQueuePositions.Add(ObjectExtent.PhysicalPosition, QueueEntry.Data);
}
}
catch
{
}
}
}
}
/// <summary>
/// Adds a Write request to the WriteQueue; if more than _MaxNumberOfQueueEntries are in the Queue
/// we wait until there's less.
/// </summary>
/// <param name="newEntry">the WriteQueueEntry</param>
public void Write(QueueEntry newEntry)
{
Boolean WriteSucceeded = false;
Int16 WriteAttempt = 0;
// Wait, while the queue is flushing its entries
while (BlockQueueInsertion)
Thread.Sleep(1);
if (ShutdownWriterThread)
throw new QueueManagerException("[WriteQueue] Write failed, because the WriteQueueThread was shut down!");
if (QueueIsOffline)
throw new QueueManagerException("[WriteQueue] Write failed, because the WriteQueueThread is offline!");
while (!WriteSucceeded && WriteAttempt <= _MaxNumberOfWriteAttempts)
{
QueueFull = false;
// Lock until WriteQueue get's free to use...
lock (WriteQueue)
{
if (WriteQueue.Count >= _MaxNumberOfQueueEntries) // Falls Puffer voll
{
QueueFull = true;
//NStorageEngine_WriteQueueFull.Arguments args = new NStorageEngine_WriteQueueFull.Arguments();
//args.NumberOfQueueEntries = NumberOfQueueEntries;
//NotificationDispatcher.SendNotification(typeof(NStorageEngine_WriteQueueFull), args);
}
}
if (QueueFull)
lock (WriteQueueHasFreeSpace)
{
// Wartet bis wieder Platz im Puffer vorhanden ist
Monitor.Wait(WriteQueueHasFreeSpace);
QueueFull = false;
}
lock (WriteQueue)
{
WriteAttempt++;
if (WriteQueue.Count < _MaxNumberOfQueueEntries)
{
WriteQueue.Add(newEntry);
// CORRECTION: Add a new Entry to Writequeue - Prevent Readqueue from reading not yet written positions
/*
foreach (var _ObjectExtent in newEntry.RWQueueStreams)
_WriteQueueLock.AddLock(_ObjectExtent.PhysicalPosition);
*/
// Debug.WriteLine("[WriteQueue] Adding new entry!");
//Debug.WriteLine("[WriteQueueThread] Added to the queue!");
// Wake the WriteQueueThread if it was fallen asleep
WriteSucceeded = true;
if (WriteQueueThreadSleeping)
lock (WriteQueueHasNewElements)
{
// Signalisiert, dass wieder ein Element vorhanden ist
Monitor.PulseAll(WriteQueueHasNewElements);
}
}
}
}
// ...fail afterwards!
// This should actually never happen!!!
if (!WriteSucceeded)
throw new QueueManagerCouldNotWriteQueueException("[WriteQueue] Could not write to the queue!");
}
/// <summary>
/// Reads a pile of data from the filesystem
/// </summary>
/// <param name="ReadEntry">a QueueEntry </param>
/// <returns></returns>
public byte[] Read(QueueEntry ReadEntry)
{
// check size
if (ReadEntry.DataLength > Int32.MaxValue)
throw new QueueManagerException("Cannot read QueueEntry - it's too big.");
byte[] Output = new byte[ReadEntry.DataLength];
// TODO: actually make use of the read queue...
if (!GraphFSFileStream.CanRead)
throw new QueueManagerException("Cannot read. Maybe nothing is mounted.");
// CORRECTION: Check if the current StartPosition is still in the WriteQueue - Prevent Readqueue from reading not yet written positions
/*
while (_WriteQueueLock.HasLock(ReadEntry.RWQueueStreams[0].PhysicalPosition))
{
Debug.WriteLine("[ReadQueue] has lock at Position " + ReadEntry.RWQueueStreams[0].PhysicalPosition);
Thread.Sleep(1); // or read next in queue
}
*/
lock (GraphFSFileStream)
{
GraphFSFileStream.Seek( (long) ReadEntry.RWQueueStreams[0].PhysicalPosition, 0);
Int32 HowMany = GraphFSFileStream.Read(Output, 0, (Int32)ReadEntry.RWQueueStreams[0].Length);
if (_BytesRead + (UInt64) HowMany < 0)
_BytesRead = 0;
_BytesRead += (UInt64) HowMany;
}
//Debug.WriteLine("[ReadQueue] Reading " + Output.Length + " bytes from position " + ReadEntry.Streams[0].Extents[0].PhysicalPosition);
//Debug.WriteLine(" \t_WriteQueuePositions" + ((List<UInt64>)UnitTestHelper.GetPrivateField("_WriteQueuePositions", _WriteQueueLock)).Count);
return Output;
}
/// <summary>
/// This method writes directly a QueueEntry as soon as possible on disc.
/// It does this by putting the QueueEntry infront of all other QueueEntries
/// within the queue.
/// In most cases this is not what you want: USE WITH CARE!
/// </summary>
/// <param name="newEntry">the QueueEntry that needs to be written as soon as possible</param>
public void DirectWrite(QueueEntry newEntry)
{
// Wait, while the queue is flushing its entries
while (BlockQueueInsertion)
Thread.Sleep(1);
if (ShutdownWriterThread)
throw new QueueManagerException("[WriteQueue] Write failed, because the WriteQueueThread was shut down!");
if (QueueIsOffline)
throw new QueueManagerException("[WriteQueue] Write failed, because the WriteQueueThread is offline!");
newEntry.FlushAfterWrite = true;
lock (WriteQueue)
{
WriteQueue.Insert(0, newEntry);
}
}
