/// <summary>
/// Read the contents of a file into a byte array, with the specified timeout and CancellationTokenSource
/// </summary>
/// <param name="fileName"></param>
/// <param name="timeoutSeconds"></param>
/// <param name="tokenSource"></param>
/// <returns></returns>
public static async Task <perTaskResult <byte[]> > ReadAllBytesFromFileAsync(
string fileName,
int timeoutSeconds,
CancellationTokenSource tokenSource)
{
using (var file = OpenFileForAsyncReading(fileName))
{
var bytes = new byte[file.Length];
var response = await file.ReadAsync(bytes, 0, (int)file.Length, tokenSource.Token)
.RunTaskWithTimeoutAsync(timeoutSeconds, tokenSource).ConfigureAwait(false);
var result = new perTaskResult <byte[]>
{
Status = response.Status,
ErrorMessage = response.ErrorMessage,
Exception = response.Exception
};
if (response.Status == perTaskStatus.CompletedOk)
{
result.Data = bytes;
}
return(result);
}
}
/// <summary>
/// run a Task T with the specified timeout / cancellation token and return the result
/// </summary>
public static async Task <perTaskResult <T> > GetTaskResultWithTimeoutAsync <T>(this Task <T> theTask, int timeoutSeconds, CancellationTokenSource tokenSource)
{
var taskResult = await theTask.RunTaskWithTimeoutAsync(timeoutSeconds, tokenSource).ConfigureAwait(false);
var result = new perTaskResult <T>
{
Status = taskResult.Status,
Exception = taskResult.Exception,
ErrorMessage = taskResult.ErrorMessage
};
// the task has already completed if status is CompletedOk, but using await once more is better than using theTask.Result
if (result.Status == perTaskStatus.CompletedOk)
{
result.Data = await theTask.ConfigureAwait(false);
}
return(result);
}
/// <summary>
/// run a task with the specified timeout and cancellation token
/// </summary>
/// <remarks>
/// tokenSource Parameter is CancellationTokenSource rather than CancellationToken as we want to trigger it in order to cancel
/// theTask (assuming it's using the same CancellationTokenSource or its token) in the event of a timeout.
/// </remarks>
public static async Task <perTaskResult> RunTaskWithTimeoutAsync(this Task theTask, int timeoutSeconds, CancellationTokenSource tokenSource)
{
var result = new perTaskResult();
// this will kill the timeout task, if the external cancellation token source is cancelled
using (var timeoutTokenSource = CancellationTokenSource.CreateLinkedTokenSource(tokenSource.Token))
{
var timeoutTask = timeoutSeconds == 0
? Task.Delay(TimeSpan.FromMilliseconds(-1), timeoutTokenSource.Token)
: Task.Delay(TimeSpan.FromSeconds(timeoutSeconds), timeoutTokenSource.Token);
var completedTask = await Task.WhenAny(theTask, timeoutTask).ConfigureAwait(false);
if (tokenSource.IsCancellationRequested)
{
result.Status = perTaskStatus.Cancelled;
}
else if (completedTask == timeoutTask)
{
result.Status = perTaskStatus.TimedOut;
// signal theTask to cancel if possible
tokenSource.Cancel();
}
else if (theTask.IsFaulted)
{
result.Status = perTaskStatus.Error;
result.Exception = theTask.Exception;
result.ErrorMessage = theTask.Exception?.GetText();
}
else
{
result.Status = perTaskStatus.CompletedOk;
}
// kill the timeoutTask if it's not already cancelled
timeoutTokenSource.Cancel();
}
return(result);
}
