public override bool Equals(object obj)
{
if (base.Equals(obj))
{
return(true);
}
FileBlockDownloadManager o = obj as FileBlockDownloadManager;
if (o == null)
{
return(false);
}
return(o._blockNumber == this._blockNumber);
}
private bool WriteBlock(FileBlockDownloadManager downloadedBlock)
{
int blockNumber = downloadedBlock.BlockNumber;
lock (_blockAvailable)
{
if (_blockAvailable[blockNumber] == FileBlockState.Available)
{
return(true);
}
byte[] blockData = downloadedBlock.BlockData;
byte[] actualHash = _metaData.BlockHash[blockNumber];
byte[] computedHash = _metaData.ComputeBlockHash(blockData);
for (int i = 0; i < actualHash.Length; i++)
{
if (actualHash[i] != computedHash[i])
{
return(false);
}
}
lock (_fileStream)
{
_fileStream.Position = blockNumber * _metaData.BlockSize;
_fileStream.Write(blockData, 0, blockData.Length);
}
_blockAvailable[blockNumber] = FileBlockState.Available;
_availableBlocksCount++;
}
Interlocked.Add(ref _bytesDownloadedLastSecond, downloadedBlock.BlockData.Length); //add bytes downloaded for transfer speed calc
return(true);
}
private void OnBlockDownloaded(FileBlockDownloadManager downloadedBlock)
{
lock (_downloadingBlocks)
{
if (_downloadingBlocks.Remove(downloadedBlock))
{
if (WriteBlock(downloadedBlock))
{
//block downloaded
//Debug.Write("SharedFile.BlockDownloaded", "block: " + downloadedBlock.BlockNumber);
if (BlockDownloaded != null)
{
RaiseEventBlockDownloaded();
}
}
else
{
//block download fail/corrupt; add block again in pending list
lock (_pendingBlocks)
{
_pendingBlocks.Add(downloadedBlock.BlockNumber);
}
}
//start new block download
FileBlockDownloadManager newDownload = GetRandomDownloadBlock();
if (newDownload != null)
{
_downloadingBlocks.Add(newDownload);
}
if (_downloadingBlocks.Count == 0)
{
//download COMPLETED!
//set variables
_isComplete = true;
_state = SharedFileState.Sharing;
_availableBlocksCount = _blockAvailable.Length;
//stop download monitor
_downloadMonitor.Dispose();
_downloadMonitor = null;
//rename and open file again in read shared mode
string filePath = _fileStream.Name;
_fileStream.Close();
File.SetLastWriteTimeUtc(filePath, _metaData.LastModified);
string newFilePath = Path.Combine(Path.GetDirectoryName(filePath), Path.GetFileNameWithoutExtension(filePath));
File.Move(filePath, newFilePath);
_fileStream = new FileStream(newFilePath, FileMode.Open, FileAccess.Read, FileShare.Read);
//remove seeders
lock (_seeders)
{
_seeders.Clear();
}
//announce advertisement for the complete file to all chats available with same file
SendFileAdvertisement();
//notify event to UI
//Debug.Write("SharedFile.BlockDownloaded", "COMPLETED!");
if (FileDownloaded != null)
{
RaiseEventFileDownloaded();
}
}
}
}
}
private void DownloadMonitorAsync(object state)
{
try
{
if (_state == SharedFileState.Paused)
{
_downloadMonitor = null;
return;
}
lock (_downloadingBlocks)
{
bool addAnotherBlockForDownload = false;
List <FileBlockDownloadManager> inactiveDownloadBlocks = new List <FileBlockDownloadManager>();
foreach (FileBlockDownloadManager download in _downloadingBlocks)
{
if ((DateTime.UtcNow - download.LastResponse).TotalSeconds > DOWNLOAD_INACTIVE_INTERVAL_SECONDS)
{
//Debug.Write("SharedFile.DownloadMonitorAsync", "InactiveBlock: " + download.BlockNumber);
if (!download.IsDownloadPeerSet())
{
//add to inactive list
inactiveDownloadBlocks.Add(download);
//add another random block if available to mitigate case when all current blocks peer are not responding
addAnotherBlockForDownload = true;
}
//remove current peer as he is not responding and set last response time
download.SetDownloadPeer(null);
//re-announce block requirement
AnnounceBlockWanted(download.BlockNumber);
}
}
//add another random block if available to mitigate case when all current blocks peer are not responding
//this will allow downloading other data blocks from other peers when current block peers not responding
if (addAnotherBlockForDownload)
{
FileBlockDownloadManager download = GetRandomDownloadBlock();
if (download != null)
{
_downloadingBlocks.Add(download);
}
}
//remove extra inactive blocks to maintain total x 2 numbe of blocks
//this will prevent memory getting filled with large number of inactive blocks
if (_downloadingBlocks.Count > TOTAL_DOWNLOAD_BLOCKS * 2)
{
foreach (FileBlockDownloadManager downloadBlock in inactiveDownloadBlocks)
{
_downloadingBlocks.Remove(downloadBlock);
if (_downloadingBlocks.Count <= TOTAL_DOWNLOAD_BLOCKS * 2)
{
break;
}
}
}
}
}
catch (ThreadAbortException)
{
_downloadMonitor = null;
}
catch (Exception ex)
{
Debug.Write("SharedFile.DownloadMonitorAsync", ex);
}
finally
{
if (_downloadMonitor != null)
{
_downloadMonitor.Change(DOWNLOAD_MONITOR_INTERVAL, Timeout.Infinite);
}
}
}
private void StartDownload()
{
if (_state != SharedFileState.Downloading)
{
_state = SharedFileState.Downloading;
//get file
if (_fileStream == null)
{
//find file name
string filePath = Path.Combine(_profile.DownloadFolder, _metaData.FileName);
int nameCount = 0;
while (File.Exists(filePath))
{
if (nameCount > 10000)
{
throw new BitChatException("Cannot download file as local file name not available.");
}
nameCount++;
filePath = Path.Combine(_profile.DownloadFolder, Path.GetFileNameWithoutExtension(_metaData.FileName) + " [" + nameCount + "]" + Path.GetExtension(_metaData.FileName));
}
//create file
_fileStream = new FileStream(filePath + ".downloading", FileMode.Create, FileAccess.ReadWrite);
//pre-allocate file
_fileStream.SetLength(_metaData.FileSize);
//init block available
_blockAvailable = new FileBlockState[_blockAvailable.Length];
_availableBlocksCount = 0;
}
//list all pending blocks
if (_pendingBlocks == null)
{
_pendingBlocks = new List <int>(_blockAvailable.Length);
_rndPendingBlock = new Random(DateTime.UtcNow.Second);
for (int i = 0; i < _blockAvailable.Length; i++)
{
if (_blockAvailable[i] != FileBlockState.Available)
{
_pendingBlocks.Add(i);
}
}
}
//announce file sharing participation in chats
SendFileShareParticipate();
//start block download
_downloadingBlocks = new List <FileBlockDownloadManager>(TOTAL_DOWNLOAD_BLOCKS);
lock (_downloadingBlocks)
{
for (int i = 0; i < TOTAL_DOWNLOAD_BLOCKS; i++)
{
FileBlockDownloadManager download = GetRandomDownloadBlock();
if (download == null)
{
break;
}
_downloadingBlocks.Add(download);
}
}
//start file transfer speed calculator
_fileTransferSpeedCalculator = new Timer(FileTransferSpeedCalculatorAsync, null, 1000, 1000);
//start download monitor
_downloadMonitor = new Timer(DownloadMonitorAsync, null, DOWNLOAD_MONITOR_INTERVAL, Timeout.Infinite);
if (FileDownloadStarted != null)
{
RaiseEventFileDownloadStarted();
}
}
}
private void OnBlockDownloaded(FileBlockDownloadManager downloadedBlock)
{
lock (_downloadingBlocks)
{
if (_downloadingBlocks.Remove(downloadedBlock))
{
if (WriteBlock(downloadedBlock))
{
//block downloaded
//Debug.Write("SharedFile.BlockDownloaded", "block: " + downloadedBlock.BlockNumber);
if (BlockDownloaded != null)
RaiseEventBlockDownloaded();
}
else
{
//block download fail/corrupt; add block again in pending list
lock (_pendingBlocks)
{
_pendingBlocks.Add(downloadedBlock.BlockNumber);
}
}
//start new block download
FileBlockDownloadManager newDownload = GetRandomDownloadBlock();
if (newDownload != null)
_downloadingBlocks.Add(newDownload);
if (_downloadingBlocks.Count == 0)
{
//download COMPLETED!
//set variables
_isComplete = true;
_state = SharedFileState.Sharing;
_availableBlocksCount = _blockAvailable.Length;
//stop download monitor
_downloadMonitor.Dispose();
_downloadMonitor = null;
//rename and open file again in read shared mode
string filePath = _fileStream.Name;
_fileStream.Close();
File.SetLastWriteTimeUtc(filePath, _metaData.LastModified);
string newFilePath = Path.Combine(Path.GetDirectoryName(filePath), Path.GetFileNameWithoutExtension(filePath));
File.Move(filePath, newFilePath);
_fileStream = new FileStream(newFilePath, FileMode.Open, FileAccess.Read, FileShare.Read);
//remove seeders
lock (_seeders)
{
_seeders.Clear();
}
//announce advertisement for the complete file to all chats available with same file
SendFileAdvertisement();
//notify event to UI
//Debug.Write("SharedFile.BlockDownloaded", "COMPLETED!");
if (FileDownloaded != null)
RaiseEventFileDownloaded();
}
}
}
}
private bool WriteBlock(FileBlockDownloadManager downloadedBlock)
{
int blockNumber = downloadedBlock.BlockNumber;
lock (_blockAvailable)
{
if (_blockAvailable[blockNumber] == FileBlockState.Available)
return true;
byte[] blockData = downloadedBlock.BlockData;
byte[] actualHash = _metaData.BlockHash[blockNumber];
byte[] computedHash = _metaData.ComputeBlockHash(blockData);
for (int i = 0; i < actualHash.Length; i++)
{
if (actualHash[i] != computedHash[i])
return false;
}
lock (_fileStream)
{
_fileStream.Position = blockNumber * _metaData.BlockSize;
_fileStream.Write(blockData, 0, blockData.Length);
}
_blockAvailable[blockNumber] = FileBlockState.Available;
_availableBlocksCount++;
}
Interlocked.Add(ref _bytesDownloadedLastSecond, downloadedBlock.BlockData.Length); //add bytes downloaded for transfer speed calc
return true;
}
