feature: supports open in/diff with VSCodium (#102)

src/Models/ExternalMerger.cs

@@ -40,6 +40,7 @@ namespace SourceGit.Models
                     new ExternalMerger(5, "kdiff3", "KDiff3", "kdiff3.exe", "\"$REMOTE\" -b \"$BASE\" \"$LOCAL\" -o \"$MERGED\"", "\"$LOCAL\" \"$REMOTE\""),
                     new ExternalMerger(6, "beyond_compare", "Beyond Compare", "BComp.exe", "\"$REMOTE\" \"$LOCAL\" \"$BASE\" \"$MERGED\"", "\"$LOCAL\" \"$REMOTE\""),
                     new ExternalMerger(7, "win_merge", "WinMerge", "WinMergeU.exe", "-u -e \"$REMOTE\" \"$LOCAL\" \"$MERGED\"", "-u -e \"$LOCAL\" \"$REMOTE\""),
+                    new ExternalMerger(8, "codium", "VSCodium", "VSCodium.exe", "-n --wait \"$MERGED\"", "-n --wait --diff \"$LOCAL\" \"$REMOTE\""),
                 };
             }
             else if (OperatingSystem.IsMacOS())
@@ -51,6 +52,7 @@ namespace SourceGit.Models
                     new ExternalMerger(3, "vscode_insiders", "Visual Studio Code - Insiders", "/Applications/Visual Studio Code - Insiders.app/Contents/Resources/app/bin/code", "-n --wait \"$MERGED\"", "-n --wait --diff \"$LOCAL\" \"$REMOTE\""),
                     new ExternalMerger(4, "kdiff3", "KDiff3", "/Applications/kdiff3.app/Contents/MacOS/kdiff3", "\"$REMOTE\" -b \"$BASE\" \"$LOCAL\" -o \"$MERGED\"", "\"$LOCAL\" \"$REMOTE\""),
                     new ExternalMerger(5, "beyond_compare", "Beyond Compare", "/Applications/Beyond Compare.app/Contents/MacOS/bcomp", "\"$REMOTE\" \"$LOCAL\" \"$BASE\" \"$MERGED\"", "\"$LOCAL\" \"$REMOTE\""),
+                    new ExternalMerger(6, "codium", "VSCodium", "/Applications/VSCodium.app/Contents/Resources/app/bin/codium", "-n --wait \"$MERGED\"", "-n --wait --diff \"$LOCAL\" \"$REMOTE\""),
                 };
             }
             else if (OperatingSystem.IsLinux())
@@ -62,6 +64,7 @@ namespace SourceGit.Models
                     new ExternalMerger(3, "kdiff3", "KDiff3", "/usr/bin/kdiff3", "\"$REMOTE\" -b \"$BASE\" \"$LOCAL\" -o \"$MERGED\"", "\"$LOCAL\" \"$REMOTE\""),
                     new ExternalMerger(4, "beyond_compare", "Beyond Compare", "/usr/bin/bcomp", "\"$REMOTE\" \"$LOCAL\" \"$BASE\" \"$MERGED\"", "\"$LOCAL\" \"$REMOTE\""),
                     new ExternalMerger(5, "meld", "Meld", "/usr/bin/meld", "\"$LOCAL\" \"$BASE\" \"$REMOTE\" -output \"$MERGED\"", "\"$LOCAL\" \"$REMOTE\""),
+                    new ExternalMerger(6, "codium", "VSCodium", "/usr/share/codium/bin/codium", "-n --wait \"$MERGED\"", "-n --wait --diff \"$LOCAL\" \"$REMOTE\""),
                 };
             }
             else

src/Models/ExternalTool.cs

@@ -126,6 +126,11 @@ namespace SourceGit.Models
             TryAdd("Visual Studio Code - Insiders", "vscode_insiders", "\"{0}\"", "VSCODE_INSIDERS_PATH", platformFinder);
         }
 
+        public void VSCodium(Func<string> platformFinder)
+        {
+            TryAdd("VSCodium", "codium", "\"{0}\"", "VSCODIUM_PATH", platformFinder);
+        }
+
         public void Fleet(Func<string> platformFinder)
         {
             TryAdd("Fleet", "fleet", "\"{0}\"", "FLEET_PATH", platformFinder);

src/Native/Linux.cs

@@ -57,6 +57,7 @@ namespace SourceGit.Native
             var finder = new Models.ExternalToolsFinder();
             finder.VSCode(() => FindExecutable("code"));
             finder.VSCodeInsiders(() => FindExecutable("code-insiders"));
+            finder.VSCodium(() => FindExecutable("codium"));
             finder.Fleet(FindJetBrainsFleet);
             finder.FindJetBrainsFromToolbox(() => $"{Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData)}/JetBrains/Toolbox");
             finder.SublimeText(() => FindExecutable("subl"));

src/Native/MacOS.cs

@@ -32,6 +32,7 @@ namespace SourceGit.Native
             var finder = new Models.ExternalToolsFinder();
             finder.VSCode(() => "/Applications/Visual Studio Code.app/Contents/Resources/app/bin/code");
             finder.VSCodeInsiders(() => "/Applications/Visual Studio Code - Insiders.app/Contents/Resources/app/bin/code");
+            finder.VSCodium(() => "/Applications/VSCodium.app/Contents/Resources/app/bin/codium");
             finder.Fleet(() => $"{Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)}/Applications/Fleet.app/Contents/MacOS/Fleet");
             finder.FindJetBrainsFromToolbox(() => $"{Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)}/Library/Application Support/JetBrains/Toolbox");
             finder.SublimeText(() => "/Applications/Sublime Text.app/Contents/SharedSupport/bin/subl");

src/Native/Windows.cs

@@ -110,6 +110,7 @@ namespace SourceGit.Native
             var finder = new Models.ExternalToolsFinder();
             finder.VSCode(FindVSCode);
             finder.VSCodeInsiders(FindVSCodeInsiders);
+            finder.VSCodium(FindVSCodium);
             finder.Fleet(() => $"{Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData)}\\Programs\\Fleet\\Fleet.exe");
             finder.FindJetBrainsFromToolbox(() => $"{Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData)}\\JetBrains\\Toolbox");
             finder.SublimeText(FindSublimeText);
@@ -323,6 +324,33 @@ namespace SourceGit.Native
             return string.Empty;
         }
 
+        private string FindVSCodium()
+        {
+            var localMachine = Microsoft.Win32.RegistryKey.OpenBaseKey(
+                    Microsoft.Win32.RegistryHive.LocalMachine,
+                    Microsoft.Win32.RegistryView.Registry64);
+
+            // VSCodium (system)
+            var systemVScodium = localMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{88DA3577-054F-4CA1-8122-7D820494CFFB}_is1");
+            if (systemVScodium != null)
+            {
+                return systemVScodium.GetValue("DisplayIcon") as string;
+            }
+
+            var currentUser = Microsoft.Win32.RegistryKey.OpenBaseKey(
+                    Microsoft.Win32.RegistryHive.CurrentUser,
+                    Microsoft.Win32.RegistryView.Registry64);
+
+            // VSCodium (user)
+            var vscodium = currentUser.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{2E1F05D1-C245-4562-81EE-28188DB6FD17}_is1");
+            if (vscodium != null)
+            {
+                return vscodium.GetValue("DisplayIcon") as string;
+            }
+
+            return string.Empty;
+        }
+
         private string FindSublimeText()
         {
             var localMachine = Microsoft.Win32.RegistryKey.OpenBaseKey(