New versioning, single instance

Added license, readme

LICENSE

@@ -0,0 +1,7 @@
+Copyright 2021 Anders Forsgren
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Program.cs

@@ -1,6 +1,7 @@
 using AudioSwitcher.AudioApi.CoreAudio;
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
 using System.Windows.Forms;
@@ -10,27 +11,44 @@ namespace KeyMute
    public static class ProgramInfo
    {
       public static string Name => System.Reflection.Assembly.GetEntryAssembly().GetName().Name;
-      public static string Version  => $"{ThisAssembly.Git.SemVer.Major}.{ThisAssembly.Git.SemVer.Minor}.{ThisAssembly.Git.SemVer.Patch}.{ThisAssembly.Git.Commits}";
+      public static string Version  => $"{ThisAssembly.Git.SemVer.Major}.{ThisAssembly.Git.SemVer.Minor}.{ThisAssembly.Git.SemVer.Patch}";
       public static string NameAndVersion => $"{Name} v{Version}";
    }
 
    static class Program
-   {   
+   {         
       [STAThread]
       static void Main()
       {
          Application.EnableVisualStyles();
          Application.SetCompatibleTextRenderingDefault(false);
-         Application.Run(new MuteAppContext());
+         var ctx = MuteAppContext.Create();
+         if (ctx != null)
+            Application.Run();
+         else
+            Application.Exit();
       }
 
       private sealed class MuteAppContext : ApplicationContext
       {
          private readonly NotifyIcon trayIcon;
          private readonly MuteForm muteForm;
+         private readonly SingleInstance singleInstance;
+
+         public static MuteAppContext Create()
+         {
+            var singleInst = SingleInstance.Create("KeyMute", 1000);
+            if (singleInst == null)
+            {
+               Debug.WriteLine("Already running.");
+               return null;
+            }
+            return new MuteAppContext(singleInst);
+         }
 
-         public MuteAppContext()
+         private MuteAppContext(SingleInstance singleInstance)
          {
+            this.singleInstance = singleInstance;
             muteForm = new MuteForm();
             trayIcon = new NotifyIcon()
             {
@@ -58,6 +76,14 @@ private void Exit()
             muteForm.Close();
             Application.Exit();
          }
+
+         protected override void Dispose(bool disposing)
+         {
+            if (disposing)
+               singleInstance?.Dispose();
+
+            base.Dispose(disposing);
+         }
       }
    }
 }

README.md

@@ -0,0 +1,30 @@
+KeyMute
+=======
+
+Windows application to  mute keys when typing. Built with [AudioSwitcher](https://github.com/xenolightning/AudioSwitcher/).  Inspired by UnClack for MacOS.
+
+NOTE: Work in progress
+
+
+Installation
+============
+
+Prerequisites: 
+.NET Runtime 4.7.1 or later (Comes preinstalled on Win10 1709 and later)
+
+
+Copy binaries and run.  
+NOTE:  
+ - No installer yet
+ - No automatic start yet
+
+
+Contributing
+============
+
+Please do
+
+License
+=======
+
+MIT License. See `LICENSE` for more information

SingleInstance.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Security.AccessControl;
+using System.Security.Principal;
+using System.Threading;
+
+namespace KeyMute
+{
+   public sealed class SingleInstance : IDisposable
+   {
+      private Mutex mutex;
+
+      private SingleInstance(Mutex mutex)
+      {
+         this.mutex = mutex;
+      }
+
+      public static SingleInstance Create(string id, int timeout)
+      {         
+         string mutexId = string.Format("Global\\{{{0}}}", id);
+
+         var allowEveryoneRule = new MutexAccessRule(new SecurityIdentifier(WellKnownSidType.WorldSid, null), MutexRights.FullControl, AccessControlType.Allow);
+         var securitySettings = new MutexSecurity();
+         securitySettings.AddAccessRule(allowEveryoneRule);
+         bool hasHandle;
+         Mutex mutex = null;
+         try
+         {
+            mutex = new Mutex(false, mutexId, out bool createdNew, securitySettings);
+            hasHandle = mutex.WaitOne(timeout, false);
+         }
+         catch (AbandonedMutexException)
+         {
+            hasHandle = true;
+         }
+
+         if (mutex != null && hasHandle)
+            return new SingleInstance(mutex);
+         else return null;
+      }
+
+      public void Dispose()
+      {
+         var m = mutex;
+         if (m != null)
+         {
+            m.ReleaseMutex();
+            mutex = null;
+         }         
+      }
+   }
+}