Lepracaun

Lepracaun - Varies of .NET Synchronization Context.

NuGet

Package	NuGet
Lepracaun

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What is this?

Lepracaun is a library that collection of .NET Synchronization Context. It is a successor of SynchContextSample library.

Class	Detail
SingleThreadedSynchronizationContext	That constrains the execution context to a single thread using simple queue.
Win32MessagingSynchronizationContext	That constrains the execution context to a single thread using the Win32 message pumps.
WorkerThreadSynchronizationContext	Create a worker thread and running on it.
Application	Pseudo (WPF/WinForms like) the Application class. Will use SingleThreadedSynchronizationContext defaulted.

Operating Environment

The following platforms are supported by the package.

• NET 8 to 5
• NET Core 3.1 to 2.0
• NET Standard 2.1 to 1.6 and 1.3
• NET Framework 4.8.1 to 3.5

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Basic usage

Single threaded

// Allocate and assigned:
using var sc = new SingleThreadedSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(sc);

// Use it directly (Post is asynchronously, so will delay execution.)
var origin = Thread.CurrentThread.ManagedThreadId;
sc.Post(_ =>
{
    var current = Thread.CurrentThread.ManagedThreadId;
    Console.WriteLine($"{origin} ==> {current}");
}, null);

// Run it:
sc.Run();

Worker thread

// Allocate and assigned:
using var sc = new WorkerThreadSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(sc);

// Use it directly (Post is asynchronously, so will delay execution.)
var origin = Thread.CurrentThread.ManagedThreadId;
sc.Post(_ =>
{
    var current = Thread.CurrentThread.ManagedThreadId;
    Console.WriteLine($"{origin} ==> {current}");
}, null);

// Run it (Worker thread will run background.)
sc.Run();

// (Wait until consume.)
Thread.Sleep(1000);

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Realistic samples

Main thread bound asynchronous operation

public static void Main(string[] args)
{
    using var app = new Application();

    //using var app = new Application(
    //    new SingleThreadedSynchronizationContext());

    app.Run(async () =>
    {
        // Your asynchronous operations
        // into only main thread (Will not use any worker threads)

        using var rs = new FileStream(...);
        using var ws = new FileStream(...);

        var buffer = new byte[1024];
        var read = await rs.ReadAsync(buffer, 0, buffer.Length);

        // (Rebound to main thread)
        await ws.WriteAsync(buffer, 0, read);

        // (Rebound to main thread)
        await ws.FlushAsync();
   
        // (Rebound to main thread)

        // ...
    });    
}

Bound temporary Win32 UI thread on any arbitrary thread context

public void MarshalInToUIThread()
{
    using var app = new Application(
        new Win32MessagingSynchronizationContext());

    // Run on worker thread.
    Task.Run(() =>
    {
        // Some longer operations...

        // Manipulate Win32 UI from worker thread context.
        app.BeginInvoke(() => Win32NativeMethods.ShowWindow(this.window));
    });

    app.Run();
}

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License

Apache-v2.

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History

• 1.1.0:
  • Fixed ignores any unhandled exceptions. (#1)
• 1.0.0:
  • Improved queue consumer.
• 0.4.0:
  • Supported .NET 7.0.
  • Fixed unmarking event field on Application class.
  • Fixed did not handle exception when runner bootstrap.
• 0.3.0:
  • Added feature of worker thread bound.
• 0.2.0:
  • Added CheckAccess method.
  • Fixed returns invalid identity.
• 0.1.0:
  • Initial stable release.
  • Added pseudo Application class.
  • Fixed a problem that SynchContext.Send() completes even though the target continuation is not completed.
• 0.0.2:
  • Initial release.