// Example class using OperationWithTimeout
public class ConvertHelper
{
public static byte[] ConvertWordToPdf(Stream inputStream)
{
var operationWithTimeout
= new OperationWithTimeout
(); TimeSpan timeout = TimeSpan.FromSeconds(30); // Timeout after 30 seconds if operation isn't done (seems like SaveToStream contains a while-loop)
Func<CancellationToken, byte[]> operation = token =>
{
// Enter your code here
using (var ms
= new MemoryStream
()) {
Document doc
= new Document
(); doc.LoadFromStream(inputStream, FileFormat.Auto);
doc.SaveToStream(ms, FileFormat.PDF);
doc.Close();
return ms.ToArray();
}
};
var task = operationWithTimeout.Execute<byte[]>(operation, timeout);
var result = task.Result;
return result;
}
}
// OperationWithTimeout
public class OperationWithTimeout
{
public Task<T> Execute<T>(Func<CancellationToken, T> operation, TimeSpan timeout)
{
var cancellationToken
= new CancellationTokenSource
();
// Two tasks are created.
// One which starts the requested operation and second which starts Timer.
// Timer is set to AutoReset = false so it runs only once after given 'delayTime'.
// When this 'delayTime' has elapsed then TaskCompletionSource.TrySetResult() method is executed.
// This method attempts to transition the 'delayTask' into the RanToCompletion state.
Task<T> operationTask = Task<T>.Factory.StartNew(() => operation(cancellationToken.Token), cancellationToken.Token);
Task delayTask = Delay(timeout.TotalMilliseconds);
// Then WaitAny() waits for any of the provided task objects to complete execution.
Task
[] tasks
= new Task
[] { operationTask, delayTask
}; Task.WaitAny(tasks);
try
{
if (!operationTask.IsCompleted)
{
// If operation task didn't finish within given timeout call Cancel() on token and throw 'TimeoutException' exception.
// If Cancel() was called then in the operation itself the property 'IsCancellationRequested' will be equal to 'true'.
cancellationToken.Cancel();
throw new TimeoutException
("Timeout waiting for method after " + timeout
+ ". Method was to slow :-)"); }
}
finally
{
cancellationToken.Dispose();
}
return operationTask;
}
public static Task Delay(double delayTime)
{
var completionSource
= new TaskCompletionSource
<bool>(); System.Timers.Timer timer
= new System.Timers.Timer(); timer.Elapsed += (obj, args) => completionSource.TrySetResult(true);
timer.Interval = delayTime;
timer.AutoReset = false;
timer.Start();
return completionSource.Task;
}
}
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