Use LRU cache for icons to improve performance when changing back and forth between frequently used apps, and reduce possibility of an icon randomly not loading

src/FocusVolumeControl/AudioHelpers/AudioHelper.cs

@@ -1,12 +1,8 @@
-using BarRaider.SdTools;
-using FocusVolumeControl.AudioSessions;
+using FocusVolumeControl.AudioSessions;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.IO;
 using System.Linq;
-using System.Runtime.InteropServices;
-using System.Text;
 
 namespace FocusVolumeControl.AudioHelpers;
 
@@ -27,6 +23,18 @@ public class AudioHelper
 		}
 	}
 
+	private Process GetProcessById(int id)
+	{
+		try
+		{
+			return Process.GetProcessById(id);
+		}
+		catch
+		{
+			return null;
+		}
+	}
+
 	public IAudioSession FindSession(List<Process> processes)
 	{
 		var results = new ActiveAudioSessionWrapper();
@@ -55,7 +63,12 @@ public class AudioHelper
 				sessionEnumerator.GetSession(i, out var session);
 
 				session.GetProcessId(out var sessionProcessId);
-				var audioProcess = Process.GetProcessById(sessionProcessId);
+				var audioProcess = GetProcessById(sessionProcessId);
+
+				if(audioProcess == null)
+				{
+					continue;
+				}
 
 				var index = processes.FindIndex(x => x.Id == sessionProcessId || x.ProcessName == audioProcess?.ProcessName);
 
@@ -68,7 +81,14 @@ public class AudioHelper
 					{
 						bestProcessMatch = audioProcess;
 						currentIndex = index;
+
+						if(string.IsNullOrEmpty(results.DisplayName))
+						{
+							session.GetDisplayName(out var displayName);
+							results.DisplayName = displayName;
 						}
+					}
+
 
 					//some apps like discord have multiple volume processes.
 					//and some apps will be on multiple devices
@@ -92,7 +112,7 @@ public class AudioHelper
 		lock (_lock)
 		{
 			var processes = GetPossibleProcesses();
-			var processIds = processes.Select(x => x.Id).ToArray();
+			var processIds = processes?.Select(x => x.Id).ToArray();
 
 			if (_currentProcesses == null || !_currentProcesses.SequenceEqual(processIds))
 			{
@@ -138,7 +158,7 @@ public class AudioHelper
 
 		if (handle == IntPtr.Zero)
 		{
-			return null;
+			return new List<Process>();
 		}
 
 		var ids = Native.GetProcessesOfChildWindows(handle);
@@ -150,6 +170,11 @@ public class AudioHelper
 						   .Select(x => Process.GetProcessById(x))
 						   .ToList();
 
+		if(processes.FirstOrDefault()?.ProcessName == "explorer")
+		{
+			return new List<Process>();
+		}
+
 		try
 		{
 			//note. in instances where you launch a game from steam. this ends up mapping the process to both steam and to the game. which is unfortunate

src/FocusVolumeControl/AudioHelpers/NameAndIconHelper.cs

@@ -26,10 +26,13 @@ public class NameAndIconHelper
 			var appx = AppxPackage.FromProcess(process);
 			if (appx == null)
 			{
-				//usingg process.MainModule.FileVersionInfo sometimes throws permission exceptions
+				//using process.MainModule.FileVersionInfo sometimes throws permission exceptions
 				//we get the file version info with a limited query flag to avoid that
 				var fileVersionInfo = GetFileVersionInfo(process);
 
+				//if the display name is already set, then it came from the display name of the audio session
+				if (string.IsNullOrEmpty(results.DisplayName))
+				{
 					results.DisplayName = process.MainWindowTitle;
 
 					if (string.IsNullOrEmpty(results.DisplayName))
@@ -40,6 +43,7 @@ public class NameAndIconHelper
 							results.DisplayName = process.ProcessName;
 						}
 					}
+				}
 
 				results.ExecutablePath = fileVersionInfo?.FileName;
 			}

src/FocusVolumeControl/AudioSessions/ActiveAudioSessionWrapper.cs

@@ -4,44 +4,59 @@ using System.Linq;
 using BarRaider.SdTools;
 using System.Drawing;
 using System.Runtime.InteropServices;
+using FocusVolumeControl.UI;
+using BitFaster.Caching.Lru;
 
 namespace FocusVolumeControl.AudioSessions;
 
 public sealed class ActiveAudioSessionWrapper : IAudioSession
 {
+	static ConcurrentLru<string, string> _iconCache = new ConcurrentLru<string, string>(10);
+
 	public string DisplayName { get; set; }
 	public string ExecutablePath { get; set; }
 	public string IconPath { get; set; }
 	private List<IAudioSessionControl2> Sessions { get; } = new List<IAudioSessionControl2>();
 	private IEnumerable<ISimpleAudioVolume> Volume => Sessions.Cast<ISimpleAudioVolume>();
 
-	string _icon;
-
-	public string GetIcon()
+	string GetIconFromIconPath()
 	{
-		if (string.IsNullOrEmpty(_icon))
-		{
-			try
-			{
-				if(!string.IsNullOrEmpty(IconPath))
+		return _iconCache.GetOrAdd(IconPath, (key) =>
 		{
 			var tmp = (Bitmap)Bitmap.FromFile(IconPath);
 			tmp.MakeTransparent();
-					_icon = Tools.ImageToBase64(tmp, true);
+			return Tools.ImageToBase64(tmp, true);
+		});
+	}
+
+	string GetIconFromExecutablePath()
+	{
+		return _iconCache.GetOrAdd(ExecutablePath, (key) =>
+		{
+			var tmp = IconExtraction.GetIcon(ExecutablePath);
+			//var tmp = Icon.ExtractAssociatedIcon(ExecutablePath);
+			return Tools.ImageToBase64(tmp, true);
+		});
+	}
+
+	public string GetIcon()
+	{
+		try
+		{
+			if (!string.IsNullOrEmpty(IconPath))
+			{
+				return GetIconFromIconPath();
 			}
 			else
 			{
-					var tmp = Icon.ExtractAssociatedIcon(ExecutablePath);
-					_icon = Tools.ImageToBase64(tmp.ToBitmap(), true);
+				return GetIconFromExecutablePath();
 			}
 		}
 		catch
 		{
-				_icon = "Images/encoderIcon";
+			return "Images/encoderIcon";
 		}
 	}
-		return _icon;
-	}
 
 	public bool Any()
 	{

src/FocusVolumeControl/FocusVolumeControl.csproj

@@ -65,6 +65,7 @@
     <Compile Include="AudioSessions\IAudioSession.cs" />
     <Compile Include="FallbackBehavior.cs" />
     <Compile Include="AudioHelpers\NameAndIconHelper.cs" />
+    <Compile Include="UI\IconExtraction.cs" />
     <Compile Include="UI\ISDConnectionExtensions.cs" />
     <Compile Include="Native.cs" />
     <Compile Include="AudioHelpers\ParentProcessUtilities.cs" />
@@ -96,6 +97,9 @@
     </Content>
   </ItemGroup>
   <ItemGroup>
+    <PackageReference Include="BitFaster.Caching">
+      <Version>2.2.1</Version>
+    </PackageReference>
     <PackageReference Include="IsExternalInit">
       <Version>1.0.3</Version>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

src/FocusVolumeControl/UI/IconExtraction.cs

@@ -0,0 +1,267 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace FocusVolumeControl.UI
+{
+	internal class IconExtraction
+	{
+		public static Bitmap GetIcon(string path)
+		{
+			var index = GetIconIndex(path);
+			var handle = GetIconHandle(index);
+
+			using var icon = (Icon)Icon.FromHandle(handle).Clone();
+
+			Shell32.DestroyIcon(handle);
+			return icon.ToBitmap();
+		}
+
+
+		static int GetIconIndex(string pszFile)
+		{
+			SHFILEINFO sfi = new SHFILEINFO();
+			Shell32.SHGetFileInfo(pszFile, 0, ref sfi, (uint)Marshal.SizeOf(sfi), (uint)(SHGFI.SysIconIndex | SHGFI.LargeIcon | SHGFI.UseFileAttributes));
+			return sfi.iIcon;
+		}
+
+		// 256*256
+		static IntPtr GetIconHandle(int iImage)
+		{
+			IImageList spiml = null;
+			Guid guil = new Guid(IID_IImageList2);//or IID_IImageList
+
+			Shell32.SHGetImageList(Shell32.SHIL_EXTRALARGE, ref guil, ref spiml);
+			IntPtr hIcon = IntPtr.Zero;
+			spiml.GetIcon(iImage, Shell32.ILD_TRANSPARENT | Shell32.ILD_IMAGE, ref hIcon);
+
+			return hIcon;
+		}
+
+		const string IID_IImageList = "46EB5926-582E-4017-9FDF-E8998DAA0950";
+		const string IID_IImageList2 = "192B9D83-50FC-457B-90A0-2B82A8B5DAE1";
+
+		public static class Shell32
+		{
+
+			public const int SHIL_LARGE = 0x0;
+			public const int SHIL_SMALL = 0x1;
+			public const int SHIL_EXTRALARGE = 0x2;
+			public const int SHIL_SYSSMALL = 0x3;
+			public const int SHIL_JUMBO = 0x4;
+			public const int SHIL_LAST = 0x4;
+
+			public const int ILD_TRANSPARENT = 0x00000001;
+			public const int ILD_IMAGE = 0x00000020;
+
+			[DllImport("shell32.dll", EntryPoint = "#727")]
+			public extern static int SHGetImageList(int iImageList, ref Guid riid, ref IImageList ppv);
+
+			[DllImport("user32.dll", EntryPoint = "DestroyIcon", SetLastError = true)]
+			public static extern int DestroyIcon(IntPtr hIcon);
+
+			//[DllImport("shell32.dll")]
+			//public static extern uint SHGetIDListFromObject([MarshalAs(UnmanagedType.IUnknown)] object iUnknown, out IntPtr ppidl);
+
+			[DllImport("Shell32.dll")]
+			public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbFileInfo, uint uFlags);
+		}
+
+		[Flags]
+		enum SHGFI : uint
+		{
+			/// <summary>get icon</summary>
+			Icon = 0x000000100,
+			/// <summary>get display name</summary>
+			DisplayName = 0x000000200,
+			/// <summary>get type name</summary>
+			TypeName = 0x000000400,
+			/// <summary>get attributes</summary>
+			Attributes = 0x000000800,
+			/// <summary>get icon location</summary>
+			IconLocation = 0x000001000,
+			/// <summary>return exe type</summary>
+			ExeType = 0x000002000,
+			/// <summary>get system icon index</summary>
+			SysIconIndex = 0x000004000,
+			/// <summary>put a link overlay on icon</summary>
+			LinkOverlay = 0x000008000,
+			/// <summary>show icon in selected state</summary>
+			Selected = 0x000010000,
+			/// <summary>get only specified attributes</summary>
+			Attr_Specified = 0x000020000,
+			/// <summary>get large icon</summary>
+			LargeIcon = 0x000000000,
+			/// <summary>get small icon</summary>
+			SmallIcon = 0x000000001,
+			/// <summary>get open icon</summary>
+			OpenIcon = 0x000000002,
+			/// <summary>get shell size icon</summary>
+			ShellIconSize = 0x000000004,
+			/// <summary>pszPath is a pidl</summary>
+			PIDL = 0x000000008,
+			/// <summary>use passed dwFileAttribute</summary>
+			UseFileAttributes = 0x000000010,
+			/// <summary>apply the appropriate overlays</summary>
+			AddOverlays = 0x000000020,
+			/// <summary>Get the index of the overlay in the upper 8 bits of the iIcon</summary>
+			OverlayIndex = 0x000000040,
+		}
+
+		[StructLayout(LayoutKind.Sequential)]
+		public struct SHFILEINFO
+		{
+			public const int NAMESIZE = 80;
+			public IntPtr hIcon;
+			public int iIcon;
+			public uint dwAttributes;
+			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
+			public string szDisplayName;
+			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
+			public string szTypeName;
+		};
+
+
+		[StructLayout(LayoutKind.Sequential)]
+		public struct RECT
+		{
+			public int left, top, right, bottom;
+		}
+
+		[StructLayout(LayoutKind.Sequential)]
+		public struct POINT
+		{
+			int x;
+			int y;
+		}
+
+		[StructLayout(LayoutKind.Sequential)]
+		public struct IMAGELISTDRAWPARAMS
+		{
+			public int cbSize;
+			public IntPtr himl;
+			public int i;
+			public IntPtr hdcDst;
+			public int x;
+			public int y;
+			public int cx;
+			public int cy;
+			public int xBitmap;    // x offest from the upperleft of bitmap
+			public int yBitmap;    // y offset from the upperleft of bitmap
+			public int rgbBk;
+			public int rgbFg;
+			public int fStyle;
+			public int dwRop;
+			public int fState;
+			public int Frame;
+			public int crEffect;
+		}
+
+		[StructLayout(LayoutKind.Sequential)]
+		public struct IMAGEINFO
+		{
+			public IntPtr hbmImage;
+			public IntPtr hbmMask;
+			public int Unused1;
+			public int Unused2;
+			public RECT rcImage;
+		}
+		[ComImportAttribute()]
+		[GuidAttribute("46EB5926-582E-4017-9FDF-E8998DAA0950")]
+		[InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
+		public interface IImageList
+		{
+			[PreserveSig]
+			int Add(IntPtr hbmImage, IntPtr hbmMask, ref int pi);
+
+			[PreserveSig]
+			int ReplaceIcon(int i, IntPtr hicon, ref int pi);
+
+			[PreserveSig]
+			int SetOverlayImage(int iImage, int iOverlay);
+
+			[PreserveSig]
+			int Replace(int i, IntPtr hbmImage, IntPtr hbmMask);
+
+			[PreserveSig]
+			int AddMasked(IntPtr hbmImage, int crMask, ref int pi);
+
+			[PreserveSig]
+			int Draw(ref IMAGELISTDRAWPARAMS pimldp);
+
+			[PreserveSig]
+			int Remove(int i);
+
+			[PreserveSig]
+			int GetIcon(int i, int flags, ref IntPtr picon);
+
+			[PreserveSig]
+			int GetImageInfo(int i, ref IMAGEINFO pImageInfo);
+
+			[PreserveSig]
+			int Copy(int iDst, IImageList punkSrc, int iSrc, int uFlags);
+
+			[PreserveSig]
+			int Merge(int i1, IImageList punk2, int i2, int dx, int dy, ref Guid riid, ref IntPtr ppv);
+
+			[PreserveSig]
+			int Clone(ref Guid riid, ref IntPtr ppv);
+
+			[PreserveSig]
+			int GetImageRect(int i, ref RECT prc);
+
+			[PreserveSig]
+			int GetIconSize(ref int cx, ref int cy);
+
+			[PreserveSig]
+			int SetIconSize(int cx, int cy);
+
+			[PreserveSig]
+			int GetImageCount(ref int pi);
+
+			[PreserveSig]
+			int SetImageCount(int uNewCount);
+
+			[PreserveSig]
+			int SetBkColor(int clrBk, ref int pclr);
+
+			[PreserveSig]
+			int GetBkColor(ref int pclr);
+
+			[PreserveSig]
+			int BeginDrag(int iTrack, int dxHotspot, int dyHotspot);
+
+			[PreserveSig]
+			int EndDrag();
+
+			[PreserveSig]
+			int DragEnter(IntPtr hwndLock, int x, int y);
+
+			[PreserveSig]
+			int DragLeave(IntPtr hwndLock);
+
+			[PreserveSig]
+			int DragMove(int x, int y);
+
+			[PreserveSig]
+			int SetDragCursorImage(ref IImageList punk, int iDrag, int dxHotspot, int dyHotspot);
+
+			[PreserveSig]
+			int DragShowNolock(int fShow);
+
+			[PreserveSig]
+			int GetDragImage(ref POINT ppt, ref POINT pptHotspot, ref Guid riid, ref IntPtr ppv);
+
+			[PreserveSig]
+			int GetItemFlags(int i, ref int dwFlags);
+
+			[PreserveSig]
+			int GetOverlayImage(int iOverlay, ref int piIndex);
+		};
+
+	}
+}

src/FocusVolumeControl/WindowChangedEventLoop.cs

@@ -39,12 +39,24 @@ namespace FocusVolumeControl
 
 		public event Action WindowChanged;
 
-		private void WinEventProc(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
+		CancellationTokenSource? _cancellationTokenSource = null;
+
+		private async void WinEventProc(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
 		{
 			try
 			{
+				//debounce the window changed events by 100 ms because if you click mouse over an application on the start bar
+				//and then click on the preview window, it will quickly go from current -> fallback -> new app
+				//which can often result in it getting stuck on the fallback app
+				_cancellationTokenSource?.Cancel();
+				_cancellationTokenSource = new CancellationTokenSource();
+				await Task.Delay(100, _cancellationTokenSource.Token);
 				WindowChanged?.Invoke();
 			}
+			catch (TaskCanceledException)
+			{
+				//ignored
+			}
 			catch (Exception ex)
 			{
 				Logger.Instance.LogMessage(TracingLevel.ERROR, $"Unexpected Error in EventHandler:\n {ex}");