static async Task ReplaceFileAsync(FileInfo fileInfo, string newFile, CancellationToken cancellationToken)
{
var fullName = fileInfo.FullName;
var backupFileName = fullName + ".bak";
File.Delete(backupFileName);
File.Replace(newFile, fullName, backupFileName);
for (var retry = 0; ; ++retry)
{
if (retry > 0)
{
await Delays.LongDelay(TimeSpan.FromMilliseconds(100 << retry), cancellationToken).ConfigureAwait(false);
}
try
{
File.Delete(backupFileName);
break;
}
catch (IOException ex)
{
if (retry >= 4)
{
throw;
}
Debug.WriteLine($"Unable to delete backup file {backupFileName}: {ex.Message}");
}
}
}
public Task <DirectoryInfo> GetDirectoryAsync(DirectoryInfo parentDirectory)
{
for (; ;)
{
if (_tempDirs.TryGetValue(parentDirectory.FullName, out var directoryInfoTask))
{
return(directoryInfoTask);
}
var task = new Task <Task <DirectoryInfo> >(
async() =>
{
for (var retry = 0; ; ++retry)
{
var path = Path.Combine(parentDirectory.FullName, "temp-" + Path.GetRandomFileName());
var directoryInfo = new DirectoryInfo(path);
if (directoryInfo.Exists)
{
return(directoryInfo);
}
if (retry > 0)
{
await Delays.LongDelay(TimeSpan.FromMilliseconds(50 << retry), CancellationToken.None).ConfigureAwait(false);
}
try
{
directoryInfo.Create();
return(directoryInfo);
}
catch (IOException ex)
{
if (retry >= 4)
{
throw;
}
Debug.WriteLine($"Unable to create temp directory {path}, retrying: {ex.Message}");
}
}
});
if (_tempDirs.TryAdd(parentDirectory.FullName, task.Unwrap()))
{
task.Start();
return(task.Unwrap());
}
}
}
public void Dispose()
{
var cleanupTasks = new List <Task>(_tempDirs.Count);
foreach (var dirTask in _tempDirs.Values)
{
if (dirTask.IsFaulted || dirTask.IsCanceled)
{
var ex = dirTask.Exception;
if (null != ex)
{
Debug.WriteLine("Directory cleanup failed: " + ex.Message);
}
continue;
}
var cleanupTask = dirTask.ContinueWith(
async t =>
{
if (t.IsFaulted)
{
var ex = t.Exception;
if (null != ex)
{
Debug.WriteLine("Directory cleanup failed: " + ex.Message);
}
return;
}
var directoryInfo = t.Result;
for (var retry = 0; retry < 5; ++retry)
{
if (retry > 0)
{
await Delays.LongDelay(TimeSpan.FromMilliseconds(100 << retry), CancellationToken.None).ConfigureAwait(false);
}
try
{
directoryInfo.Refresh();
if (directoryInfo.Exists)
{
directoryInfo.Delete(true);
}
}
catch (IOException ex)
{
if (retry >= 4)
{
throw;
}
Debug.WriteLine("Directory cleanup of {0} failed, retrying: {1}", directoryInfo.FullName, ex.Message);
}
}
}, TaskContinuationOptions.RunContinuationsAsynchronously);
cleanupTasks.Add(cleanupTask);
}
try
{
Task.WaitAll(cleanupTasks.ToArray());
}
catch (Exception ex)
{
Debug.WriteLine("Directory cleanup failed: " + ex.Message);
}
}