Convert to C# and add Github Action to compile it

Co-authored-by: Henry Franks <henryefranks@gmail.com>

.github/workflows/build.yml

@@ -0,0 +1,31 @@
+name: Charon Build
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  build:
+    runs-on: windows-latest
+
+    steps:
+      - uses: webfactory/ssh-agent@v0.5.3
+        with:
+          ssh-private-key: ${{ secrets.DEPLOY_KEY }}
+      - name: Prepare
+        run: |
+          git clone https://github.com/smh-my-head/charon
+          git clone git@github.com:smh-my-head/charon-build-assets
+          mkdir charon/compare/build
+          cp charon-build-assets/* charon/compare/build
+
+      - name: Build
+        run: |
+          cd charon/compare
+          dotnet.exe publish -r win-x64 -o build --nologo --configuration "Release" /p:PublishSingleFile=true /p:IncludeNativeLibrariesForSelfExtract=true
+      - name: Release
+        uses: softprops/action-gh-release@v1
+        with:
+          files: |
+            charon/compare/build/compare.exe

.gitignore

@@ -0,0 +1,4 @@
+/test
+/compare/bin
+/compare/obj
+/compare/build

README.md

@@ -1,14 +1,10 @@
 # Charon
 The ferryman to Hell (aka CAD version control). Provides integration with git
-for SolidWorks parts and assemblies.
+for SolidWorks parts and assemblies. Fully integrated with [Hades](https://github.com/smh-my-head/hades)
 
 ## Usage
 
-Add this repo as a submodule and then run `./charon/setup.sh` from Git Bash or
-MSYS2. You can then use git as normal, but `git diff` and `git merge` will have
-added sugar. If you use Linux, check out
-[hades](https://github.com/smh-my-head/hades), as the two projects are fully
-integrated.
+See the CUSF wiki page on [Charon](https://wiki.cusf.co.uk/Charon).
 
 You will also need to enable *SOLIDWORKS Utilities* at startup, you can do this
 by navigating (in SolidWorks) to *Tools->Add-Ins* and checking the box for

charon_diff.sh

@@ -64,7 +64,6 @@ if ! $driver --check-health; then
 	echo "File $1 differs"
 else
 	echo "Opening $prog_name to diff $1..."
-	echo "$prog_name must exit fully before this diff can exit"
 	$driver $left_filename $right_filename
 fi
 

compare/Marshal2.cs

@@ -0,0 +1,55 @@
+// https://stackoverflow.com/a/65496277
+using System;
+using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
+using System.Security;
+
+public static class Marshal2
+{
+    internal const String OLEAUT32 = "oleaut32.dll";
+    internal const String OLE32 = "ole32.dll";
+
+    [System.Security.SecurityCritical]  // auto-generated_required
+    public static Object GetActiveObject(String progID)
+    {
+        Object obj = null;
+        Guid clsid;
+
+        // Call CLSIDFromProgIDEx first then fall back on CLSIDFromProgID if
+        // CLSIDFromProgIDEx doesn't exist.
+        try
+        {
+            CLSIDFromProgIDEx(progID, out clsid);
+        }
+        //            catch
+        catch (Exception)
+        {
+            CLSIDFromProgID(progID, out clsid);
+        }
+
+        GetActiveObject(ref clsid, IntPtr.Zero, out obj);
+        return obj;
+    }
+
+    //[DllImport(Microsoft.Win32.Win32Native.OLE32, PreserveSig = false)]
+    [DllImport(OLE32, PreserveSig = false)]
+    [ResourceExposure(ResourceScope.None)]
+    [SuppressUnmanagedCodeSecurity]
+    [System.Security.SecurityCritical]  // auto-generated
+    private static extern void CLSIDFromProgIDEx([MarshalAs(UnmanagedType.LPWStr)] String progId, out Guid clsid);
+
+    //[DllImport(Microsoft.Win32.Win32Native.OLE32, PreserveSig = false)]
+    [DllImport(OLE32, PreserveSig = false)]
+    [ResourceExposure(ResourceScope.None)]
+    [SuppressUnmanagedCodeSecurity]
+    [System.Security.SecurityCritical]  // auto-generated
+    private static extern void CLSIDFromProgID([MarshalAs(UnmanagedType.LPWStr)] String progId, out Guid clsid);
+
+    //[DllImport(Microsoft.Win32.Win32Native.OLEAUT32, PreserveSig = false)]
+    [DllImport(OLEAUT32, PreserveSig = false)]
+    [ResourceExposure(ResourceScope.None)]
+    [SuppressUnmanagedCodeSecurity]
+    [System.Security.SecurityCritical]  // auto-generated
+    private static extern void GetActiveObject(ref Guid rclsid, IntPtr reserved, [MarshalAs(UnmanagedType.Interface)] out Object ppunk);
+
+}