code-cursor: add mime registration (#507402)

pkgs/by-name/co/code-cursor/package.nix

@@ -22,7 +22,7 @@ let
 
   source = sources.${hostPlatform.system};
 in
-buildVscode rec {
+(buildVscode rec {
   inherit commandLineArgs useVSCodeRipgrep;
   inherit (sourcesJson) version vscodeVersion;
 
@@ -58,7 +58,7 @@ buildVscode rec {
   # See https://eclecticlight.co/2022/06/17/app-security-changes-coming-in-ventura/ for more information.
   dontFixup = stdenv.hostPlatform.isDarwin;
 
-  # Cursor has no wrapper script.
+  # Cursor ships a launcher script that resolves its own VSCODE_PATH.
   patchVSCodePath = false;
 
   meta = {
@@ -79,4 +79,18 @@ buildVscode rec {
     ++ lib.platforms.darwin;
     mainProgram = "cursor";
   };
-}
+}).overrideAttrs
+  (oldAttrs: {
+    preFixup =
+      (oldAttrs.preFixup or "")
+      + lib.optionalString hostPlatform.isLinux ''
+        sed -i '/^Keywords=/a MimeType=application/x-cursor-workspace;' \
+          $out/share/applications/cursor.desktop
+      '';
+    postInstall =
+      (oldAttrs.postInstall or "")
+      + lib.optionalString hostPlatform.isLinux ''
+        install -Dm644 ../mime/packages/cursor-workspace.xml -t $out/share/mime/packages
+        rm -f $out/lib/cursor/resources/appimageupdatetool.AppImage
+      '';
+  })