Support For Interruptable Library

Interruptable Library

In Aspose.Slides 18.4, we added the InterruptionToken class and InterruptionTokenSource class. They provide support for the interruption of long-running tasks, such as deserialization, serialization, or rendering.

• InterruptionTokenSource represents the source of the token or multiple tokens passed to ILoadOptions.InterruptionToken.
• When the ILoadOptions.InterruptionToken is set and the LoadOptions instance is passed to the Presentation constructor, invoking the InterruptionTokenSource.Interrupt method causes the interruption of any long-running task related to the Presentation.

This code snippet below demonstrates the interruption of a running task:

public static void Run()
{
    Action<IInterruptionToken> action = (IInterruptionToken token) =>
    {
        LoadOptions options = new LoadOptions { InterruptionToken = token };
        using (Presentation presentation = new Presentation("pres.pptx", options))
        {
            presentation.Save("pres.ppt", SaveFormat.Ppt);
        }
    };

    InterruptionTokenSource tokenSource = new InterruptionTokenSource();
    Run(action, tokenSource.Token); // run action in a separate thread
    Thread.Sleep(10000);            // timeout
    tokenSource.Interrupt();        // stop conversion


}
private static void Run(Action<IInterruptionToken> action, IInterruptionToken token)
{
    Task.Run(() => { action(token); });
}

.NET CancellationToken and Interruptable Library

When you need to use the CancellationToken alongside Slides Interruptable Library, you can wrap the Presentation processing and interrupt InterruptionToken if cancellationToken.IsCancellationRequested is set to true.

This C# code demonstrates the described operation:

public static void Main()
{
    CancellationTokenSource tokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(20));
    ProcessPresentation("pres.pptx", "pres.pdf", tokenSource.Token);
}

static void ProcessPresentation(string path, string outPath, CancellationToken cancellationToken)
{
    Action<IInterruptionToken> action = (IInterruptionToken token) =>
    {
        LoadOptions options = new LoadOptions {InterruptionToken = token};
        using (Presentation presentation = new Presentation(path, options))
        {
            presentation.Save(outPath, SaveFormat.Pdf);
        }
    };
    
    InterruptionTokenSource tokenSource = new InterruptionTokenSource();
    Task task = Run(action, tokenSource.Token); // run action in a separate thread

    while (!task.Wait(500)) // wait to monitor if cancellationToken.IsCancellationRequested is set. 
    {
        if (cancellationToken.IsCancellationRequested)
        {
            Console.WriteLine("Presentation processing was canceled");
            tokenSource.Interrupt(); // interrupt Presentation processing
        }
    }
}

private static Task Run(Action<IInterruptionToken> action, IInterruptionToken token)
{
    return Task.Run(() =>
    {
        action(token);
    });
}