BiliRanking.Core.Download.MultiThreadedWebDownloader.DownloadInternal C# (CSharp) Method

        void DownloadInternal(object obj)
        {
            if (this.Status != DownloadStatus.Waiting)
            {
                return;
            }

            try
            {
                this.EnsurePropertyValid();

                // Set the status.
                this.Status = DownloadStatus.Downloading;

                if (!this.HasChecked)
                {
                    string filename = null;
                    this.CheckUrlAndFile(out filename);
                }

                // If the file does not support "Accept-Ranges" header, then create one
                // HttpDownloadClient to download the file in a single thread, else create
                // multiple HttpDownloadClients to download the file.
                if (!IsRangeSupported)
                {
                    HttpDownloadClient client = new HttpDownloadClient(
                        this.Url.AbsoluteUri,
                        0,
                        long.MaxValue,
                        this.BufferSize,
                        this.BufferCountPerNotification * this.BufferSize,
                        this.BufferCountPerNotification);

                    // Set the HasChecked flag, so the client will not check the URL again.
                    client.TotalSize = this.TotalSize;
                    client.DownloadPath = this.DownloadPath;
                    client.HasChecked = true;
                    client.Credentials = this.Credentials;
                    client.Proxy = this.Proxy;

                    this.downloadClients.Add(client);
                }
                else
                {
                    // Calculate the block size for each client to download.
                    int maxSizePerThread =
                        (int)Math.Ceiling((double)this.TotalSize / this.MaxThreadCount);
                    if (maxSizePerThread < this.MaxCacheSize)
                    {
                        maxSizePerThread = this.MaxCacheSize;
                    }

                    long leftSizeToDownload = this.TotalSize;

                    // The real threads count number is the min value of MaxThreadCount and
                    // TotalSize / MaxCacheSize.
                    int threadsCount =
                        (int)Math.Ceiling((double)this.TotalSize / maxSizePerThread);

                    for (int i = 0; i < threadsCount; i++)
                    {
                        long endPoint = maxSizePerThread * (i + 1) - 1;
                        long sizeToDownload = maxSizePerThread;

                        if (endPoint > this.TotalSize)
                        {
                            endPoint = this.TotalSize - 1;
                            sizeToDownload = endPoint - maxSizePerThread * i;
                        }

                        // Download a block of the whole file.
                        HttpDownloadClient client = new HttpDownloadClient(
                            this.Url.AbsoluteUri,
                            maxSizePerThread * i,
                            endPoint);

                        // Set the HasChecked flag, so the client will not check the URL again.
                        client.DownloadPath = this.DownloadPath;
                        client.HasChecked = true;
                        client.TotalSize = sizeToDownload;
                        client.Credentials = this.Credentials;
                        client.Proxy = this.Proxy;
                        this.downloadClients.Add(client);
                    }
                }

                // Set the lastStartTime to calculate the used time.
                lastStartTime = DateTime.Now;

                // Start all HttpDownloadClients.
                foreach (var client in this.downloadClients)
                {
                    if (this.Proxy != null)
                    {
                        client.Proxy = this.Proxy;
                    }

                    // Register the events of HttpDownloadClients.
                    client.DownloadProgressChanged += client_DownloadProgressChanged;
                    client.StatusChanged += client_StatusChanged;
                    client.DownloadCompleted += client_DownloadCompleted;

                    client.BeginDownload();
                }
            }
            catch (Exception ex)
            {
                this.Cancel();
                this.OnDownloadCompleted(new DownloadCompletedEventArgs(
                    null,
                    this.DownloadedSize,
                    this.TotalSize,
                    this.TotalUsedTime,
                    ex));
            }
        }