sane-open: special-case how i open .desktop files to be compatible with portals

hosts/common/programs/sane-open.nix

@@ -16,6 +16,6 @@
       "xdg-utils"
     ];
 
-    mime.associations."application/x-desktop" = "sane-open-application.desktop";
+    mime.associations."application/x-desktop" = "sane-open-desktop.desktop";
   };
 }

pkgs/additional/sane-open/default.nix

@@ -11,9 +11,10 @@ static-nix-shell.mkBash {
   ];
   desktopItems = [
     (makeDesktopItem {
-      name = "sane-open-application";
+      name = "sane-open-desktop";
-      exec = "sane-open --application %f";
+      exec = "sane-open --desktop-file %f";
       desktopName = ".desktop launcher";
+      mimeTypes = [ "application/x-desktop" ];
       noDisplay = true;
     })
   ];

pkgs/additional/sane-open/sane-open

@@ -83,6 +83,32 @@ open_file() {
     --method org.freedesktop.portal.OpenURI.OpenFile \
     '' 3 "{'ask': <false>}"
 }
+open_desktopFile() {
+  log "open_desktopFile: '$1'"
+  # open_application (i.e. the DynamicLauncher portal) only understands applications by their
+  # .desktop filename (relative to ~/.local/share/applications) -- not by their full path.
+  # therefore, see if this .desktop file is equivalent to anything in ~/.local/share/applications.
+  local path="$1"
+  if [[ "${path:0:1}" != "/" ]]; then
+    path="$PWD/$path"
+  fi
+  if [[ "$path" == $HOME/.local/share/applications/*.desktop ]]; then
+    open_application "$(basename "$path")"
+    return
+  fi
+
+  # the given path doesn't exist in ~/.local/share/applications: check if it's a symlink which
+  # derefs to an application
+  local target="$(readlink "$path")"
+  if [ -z "$target" ]; then
+    log "open_desktopFile: '$path' does not deref to anything in ~/.local/share/applications: don't know how to launch"
+    exit 1
+  fi
+  if [[ "${target:0:1}" != "/" ]]; then
+    target="$(dirname "$path")/$target"
+  fi
+  open_desktopFile "$target"
+}
 
 
 isLandscape() {
@@ -143,6 +169,9 @@ while [ $# -gt 0 ]; do
     "--application")
       resourceType="application"
       ;;
+    "--desktop-file")
+      resourceType="desktopFile"
+      ;;
     "--file")
       resourceType="file"
       ;;