nixos/flatpak: allow specifying extra portals

4 files changed, 108 insertions, 8 deletions

diff --git a/nixos/modules/services/desktops/flatpak.nix b/nixos/modules/services/desktops/flatpak.nix
index d191eeff990..23480e65267 100644
--- a/nixos/modules/services/desktops/flatpak.nix
+++ b/nixos/modules/services/desktops/flatpak.nix
@@ -3,26 +3,45 @@
 
 with lib;
 
-{
+let
+  cfg = config.services.flatpak;
+in {
   ###### interface
   options = {
     services.flatpak = {
       enable = mkEnableOption "flatpak";
+
+      extraPortals = mkOption {
+        type = types.listOf types.package;
+        default = [];
+        description = ''
+          List of additional portals to add to path. Portals allow interaction
+          with system, like choosing files or taking screenshots. At minimum,
+          a desktop portal implementation should be listed. GNOME already
+          adds <package>xdg-desktop-portal-gtk</package>; for KDE, there
+          is <package>xdg-desktop-portal-kde</package>. Other desktop
+          environments will probably want to do the same.
+        '';
+      };
     };
   };
 
 
   ###### implementation
-  config = mkIf config.services.flatpak.enable {
+  config = mkIf cfg.enable {
     environment.systemPackages = [ pkgs.flatpak ];
 
-    services.dbus.packages = [ pkgs.flatpak ];
+    services.dbus.packages = [ pkgs.flatpak pkgs.xdg-desktop-portal ] ++ cfg.extraPortals;
+
+    systemd.packages = [ pkgs.flatpak pkgs.xdg-desktop-portal ] ++ cfg.extraPortals;
 
-    systemd.packages = [ pkgs.flatpak ];
+    environment.variables = {
+      PATH = [
+        "$HOME/.local/share/flatpak/exports/bin"
+        "/var/lib/flatpak/exports/bin"
+      ];
 
-    environment.variables.PATH = [
-      "$HOME/.local/share/flatpak/exports/bin"
-      "/var/lib/flatpak/exports/bin"
-    ];
+      XDG_DESKTOP_PORTAL_PATH = map (p: "${p}/share/xdg-desktop-portal/portals") cfg.extraPortals;
+    };
   };
 }
diff --git a/nixos/modules/services/x11/desktop-managers/gnome3.nix b/nixos/modules/services/x11/desktop-managers/gnome3.nix
index 10e8ef0ed38..27b62df7097 100644
--- a/nixos/modules/services/x11/desktop-managers/gnome3.nix
+++ b/nixos/modules/services/x11/desktop-managers/gnome3.nix
@@ -120,6 +120,7 @@ in {
     services.xserver.libinput.enable = mkDefault true; # for controlling touchpad settings via gnome control center
     services.udev.packages = [ pkgs.gnome3.gnome-settings-daemon ];
     systemd.packages = [ pkgs.gnome3.vino ];
+    services.flatpak.extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
 
     # If gnome3 is installed, build vim for gtk3 too.
     nixpkgs.config.vim.gui = "gtk3";
diff --git a/pkgs/development/libraries/xdg-desktop-portal/default.nix b/pkgs/development/libraries/xdg-desktop-portal/default.nix
index 6721d5f00ac..98bd8ba23bb 100644
--- a/pkgs/development/libraries/xdg-desktop-portal/default.nix
+++ b/pkgs/development/libraries/xdg-desktop-portal/default.nix
@@ -14,6 +14,10 @@ in stdenv.mkDerivation rec {
     sha256 = "06gipd51snvlp2jp68v2c8rwbsv36kjzg9xacm81n1w4b2dpz4g0";
   };
 
+  patches = [
+    ./respect-path-env-var.patch
+  ];
+
   nativeBuildInputs = [ autoreconfHook pkgconfig libxml2 ];
   buildInputs = [ glib pipewire fuse ];
 
diff --git a/pkgs/development/libraries/xdg-desktop-portal/respect-path-env-var.patch b/pkgs/development/libraries/xdg-desktop-portal/respect-path-env-var.patch
new file mode 100644
index 00000000000..f884899ecd1
--- /dev/null
+++ b/pkgs/development/libraries/xdg-desktop-portal/respect-path-env-var.patch
@@ -0,0 +1,76 @@
+--- a/src/xdg-desktop-portal.c
++++ b/src/xdg-desktop-portal.c
+@@ -177,38 +177,50 @@
+ static void
+ load_installed_portals (void)
+ {
+-  const char *portal_dir = PKGDATADIR "/portals";
+-  g_autoptr(GFile) dir = g_file_new_for_path (portal_dir);
+-  g_autoptr(GFileEnumerator) enumerator = NULL;
+ 
+-  enumerator = g_file_enumerate_children (dir, "*", G_FILE_QUERY_INFO_NONE, NULL, NULL);
++  g_auto(GStrv) portal_dir_list;
++  int i;
++  const char *portal_dir = g_getenv ("XDG_DESKTOP_PORTAL_PATH");
++
++  if (portal_dir == NULL)
++    portal_dir = PKGDATADIR "/portals";
+ 
+-  if (enumerator == NULL)
+-    return;
++  portal_dir_list = g_strsplit (portal_dir, G_SEARCHPATH_SEPARATOR_S, 0);
+ 
+-  while (TRUE)
++  for (i = 0; portal_dir_list[i] != NULL; i++)
+     {
+-      g_autoptr(GFileInfo) info = g_file_enumerator_next_file (enumerator, NULL, NULL);
+-      g_autoptr(GFile) child = NULL;
+-      g_autofree char *path = NULL;
+-      const char *name;
+-      g_autoptr(GError) error = NULL;
++      portal_dir = portal_dir_list[i];
++      g_autoptr(GFile) dir = g_file_new_for_path (portal_dir);
++      g_autoptr(GFileEnumerator) enumerator = NULL;
++      enumerator = g_file_enumerate_children (dir, "*", G_FILE_QUERY_INFO_NONE, NULL, NULL);
+ 
+-      if (info == NULL)
+-        break;
++      if (enumerator == NULL)
++        continue;
+ 
+-      name = g_file_info_get_name (info);
++      while (TRUE)
++        {
++          g_autoptr(GFileInfo) info = g_file_enumerator_next_file (enumerator, NULL, NULL);
++          g_autoptr(GFile) child = NULL;
++          g_autofree char *path = NULL;
++          const char *name;
++          g_autoptr(GError) error = NULL;
+ 
+-      if (!g_str_has_suffix (name, ".portal"))
+-        continue;
++          if (info == NULL)
++            break;
+ 
+-      child = g_file_enumerator_get_child (enumerator, info);
+-      path = g_file_get_path (child);
++          name = g_file_info_get_name (info);
+ 
+-      if (!register_portal (path, &error))
+-        {
+-          g_warning ("Error loading %s: %s", path, error->message);
+-          continue;
++          if (!g_str_has_suffix (name, ".portal"))
++            continue;
++
++          child = g_file_enumerator_get_child (enumerator, info);
++          path = g_file_get_path (child);
++
++          if (!register_portal (path, &error))
++            {
++              g_warning ("Error loading %s: %s", path, error->message);
++              continue;
++            }
+         }
+     }
+