/// <summary> 执行下载 </summary>
bool DownloadPackages(DoWorkEventArgs e)
{
Directory.CreateDirectory(Context.UpdatePackagePath);
Trace.TraceInformation("开始下载网络更新包");
var workerCount = Math.Max(1, Context.MultipleDownloadCount);
var workers = new List <WebClient>(workerCount);
var evt = new AutoResetEvent(false);
var hasError = false;
//Ping
if (!string.IsNullOrEmpty(Context.UpdateMeta.UpdatePingUrl))
{
try
{
Context.CreateWebClient().UploadData(new Uri(Context.UpdateMeta.UpdatePingUrl), new byte[0]);
}
catch (Exception)
{
}
}
//生成下载队列
Trace.TraceInformation("正在初始化 {0} 个WebClient", workerCount);
for (var i = 0; i < workerCount; i++)
{
var client = Context.CreateWebClient();
client.DownloadFileCompleted += (s, e) =>
{
var pkg = e.UserState as Package;
var cnt = s as WebClient;
pkg.LastError = e.Error;
if (e.Error != null)
{
Trace.TraceWarning($"包【{pkg.Name}】下载失败：{e.Error.Message}");
OnPackageDownloadFailed(new PackageEventArgs(pkg));
}
else if (pkg.IsLocalFileValid != true)
{
Trace.TraceWarning($"包【{pkg.Name}】MD5校验失败", "错误");
pkg.LastError = new Exception("不文件哈希值不正确或文件不存在");
OnPackageHashMismatch(new PackageEventArgs(pkg));
}
if (pkg.LastError != null)
{
//如果出错，且重试次数在限制范围内，则重试
pkg.IncreaseFailureCounter();
if (pkg.RetryCount <= Context.MaxiumRetryDownloadCount)
{
Trace.TraceWarning($"包【{pkg.Name}】未能成功下载，正在进行第 {pkg.RetryCount} 次重试，最大重试次数为 {Context.MaxiumRetryDownloadCount}", "错误");
cnt.DownloadFileAsync(new Uri(pkg.SourceUri), pkg.LocalSavePath, pkg);
OnPackageDownloadRetried(new PackageEventArgs(pkg));
return;
}
//标记出错
hasError = true;
}
//包下载完成事件
pkg.IsDownloading = false;
pkg.IsDownloaded = pkg.LastError == null;
OnPackageDownloadFinished(new PackageEventArgs(e.UserState as Package));
lock (Packages)
{
Trace.TraceInformation($"包【{pkg.Name}】下载操作完成：{(pkg.IsDownloaded ? "下载成功" : "下载失败")}");
evt.Set();
}
};
client.DownloadProgressChanged += (s, e) =>
{
var pkg = e.UserState as Package;
pkg.DownloadedSize = e.BytesReceived;
pkg.Size = e.TotalBytesToReceive > 0 ? e.TotalBytesToReceive : pkg.Size;
OnDownloadProgressChanged(new PackageDownloadProgressChangedEventArgs(pkg, pkg.Size,
pkg.DownloadedSize, e.ProgressPercentage));
};
workers.Add(client);
}
//开始处理事务
while (!hasError)
{
var breakFlag = false;
lock (Packages)
{
//没有错误，则分配下个任务
WebClient client;
while ((client = workers.Find(s => !s.IsBusy)) != null)
{
var nextPkg = Packages.Find(s => !s.IsDownloading && !s.IsDownloaded);
if (nextPkg == null)
{
breakFlag = true;
break;
}
nextPkg.IsDownloading = true;
Trace.TraceInformation($"包【{nextPkg.Name}】开始下载");
OnPackageDownload(new PackageEventArgs(nextPkg));
Context.ResetWebClient(client);
client.DownloadFileAsync(new Uri(Context.GetUpdatePackageFullUrl(nextPkg.Name)), nextPkg.LocalSavePath, nextPkg);
}
}
if (breakFlag)
{
break;
}
evt.WaitOne();
Trace.TraceInformation("线程同步事件已收到");
}
//不管任何原因中止下载，到这里时都需要等待所有客户端中止
while (true)
{
//出错了，那么对所有的客户端发出中止命令。这里不需要判断是否忙碌。
if (hasError)
{
Trace.TraceWarning("出现错误，正在取消所有包的下载队列");
workers.ForEach(s => s.CancelAsync());
}
lock (Packages)
{
Trace.TraceInformation("等待下载队列完成操作");
if (workers.FindIndex(s => s.IsBusy) == -1)
{
break;
}
}
evt.WaitOne();
}
Trace.TraceInformation("完成下载网络更新包");
var errorPkgs = Packages.FindAll(m => m.LastError != null);
if (errorPkgs.Count > 0)
{
throw new PackageDownloadException(errorPkgs.ToArray());
}
return(!hasError);
}
