stable

src/Kniip/Infrastructure/SingleInstance.cs

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+using System;
+using System.IO;
+using System.IO.Pipes;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Kniip.Infrastructure;
+
+/// <summary>
+/// Zorgt dat kniip maar één keer draait. Een tweede start stuurt zijn argumenten
+/// via een named pipe door naar de eerste instantie en sluit daarna af.
+/// </summary>
+internal sealed class SingleInstance : IDisposable
+{
+    private static readonly string BaseName = "Kniip-" + Environment.UserName;
+    private static readonly string PipeName = BaseName + "-pipe";
+
+    private readonly CancellationTokenSource _cts = new();
+    private Mutex? _mutex;
+
+    public bool TryAcquire()
+    {
+        _mutex = new Mutex(true, BaseName + "-mutex", out bool createdNew);
+        return createdNew;
+    }
+
+    public static bool SendToPrimary(string[] args)
+    {
+        try
+        {
+            using var client = new NamedPipeClientStream(".", PipeName, PipeDirection.Out);
+            client.Connect(3000);
+            using var writer = new StreamWriter(client, Encoding.UTF8);
+            writer.Write(string.Join("\n", args));
+            writer.Flush();
+            return true;
+        }
+        catch (Exception)
+        {
+            return false;
+        }
+    }
+
+    public void StartServer(Action<string[]> onArguments)
+    {
+        Task.Run(async () =>
+        {
+            while (!_cts.IsCancellationRequested)
+            {
+                try
+                {
+                    await using var server = new NamedPipeServerStream(PipeName, PipeDirection.In, 1,
+                        PipeTransmissionMode.Byte, PipeOptions.Asynchronous | PipeOptions.CurrentUserOnly);
+                    await server.WaitForConnectionAsync(_cts.Token);
+                    using var reader = new StreamReader(server, Encoding.UTF8);
+                    string content = await reader.ReadToEndAsync(_cts.Token);
+                    string[] args = content.Length == 0
+                        ? Array.Empty<string>()
+                        : content.Split('\n', StringSplitOptions.RemoveEmptyEntries);
+                    onArguments(args);
+                }
+                catch (OperationCanceledException)
+                {
+                    break;
+                }
+                catch (Exception)
+                {
+                    await Task.Delay(500);
+                }
+            }
+        });
+    }
+
+    public void Dispose()
+    {
+        _cts.Cancel();
+        if (_mutex != null)
+        {
+            try { _mutex.ReleaseMutex(); } catch (ApplicationException) { }
+            _mutex.Dispose();
+        }
+    }
+}