Add a popover menu to switch languages

src/popover.rs

@@ -0,0 +1,158 @@
+/*! The layout chooser popover */
+
+use gio;
+use gtk;
+use ::layout::c::EekGtkKeyboard;
+
+use gio::ActionExt;
+use gio::ActionMapExt;
+use gio::SettingsExt;
+use glib::translate::FromGlibPtrNone;
+use glib::variant::ToVariant;
+use gtk::PopoverExt;
+use gtk::WidgetExt;
+use std::io::Write;
+
+mod variants {
+    use glib;
+    use glib_sys;
+
+    use glib::translate::FromGlibPtrFull;
+    use glib::translate::ToGlibPtr;
+
+    /// Unpacks tuple & array variants
+    fn get_items(items: glib::Variant) -> Vec<glib::Variant> {
+        let variant_naked = items.to_glib_none().0;
+        let count = unsafe { glib_sys::g_variant_n_children(variant_naked) };
+        (0..count).map(|index| 
+            unsafe {
+                glib::Variant::from_glib_full(
+                    glib_sys::g_variant_get_child_value(variant_naked, index)
+                )
+            }
+        ).collect()
+    }
+
+    /// Unpacks "a(ss)" variants
+    pub fn get_tuples(items: glib::Variant) -> Vec<(String, String)> {
+        get_items(items)
+            .into_iter()
+            .map(get_items)
+            .map(|v| {
+                (
+                    v[0].get::<String>().unwrap(),
+                    v[1].get::<String>().unwrap(),
+                )
+            })
+            .collect()
+    }
+}
+
+fn make_menu_builder(inputs: Vec<&str>) -> gtk::Builder {
+    let mut xml: Vec<u8> = Vec::new();
+    writeln!(
+        xml,
+        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
+<interface>
+  <menu id=\"app-menu\">
+    <section>"
+    ).unwrap();
+    for input in inputs {
+        writeln!(
+            xml,
+            "
+        <item>
+            <attribute name=\"label\" translatable=\"yes\">{}</attribute>
+            <attribute name=\"action\">layout</attribute>
+            <attribute name=\"target\">{0}</attribute>
+        </item>",
+            input,
+        ).unwrap();
+    }
+    writeln!(
+        xml,
+        "
+    </section>
+  </menu>
+</interface>"
+    ).unwrap();
+    gtk::Builder::new_from_string(
+        &String::from_utf8(xml).expect("Bad menu definition")
+    )
+}
+
+fn set_layout(kind: String, name: String) {
+    let settings = gio::Settings::new("org.gnome.desktop.input-sources");
+    let inputs = settings.get_value("sources").unwrap();
+    let inputs = variants::get_tuples(inputs).into_iter();
+    for (index, (ikind, iname)) in inputs.enumerate() {
+        if (&ikind, &iname) == (&kind, &name) {
+            settings.set_uint("current", index as u32);
+        }
+    }
+    settings.apply();
+}
+
+pub fn show(window: EekGtkKeyboard, position: ::layout::c::Bounds) {
+    unsafe { gtk::set_initialized() };
+    let window = unsafe { gtk::Widget::from_glib_none(window.0) };
+    
+    let settings = gio::Settings::new("org.gnome.desktop.input-sources");
+    let inputs = settings.get_value("sources").unwrap();
+    let current = settings.get_uint("current") as usize;
+    let inputs = variants::get_tuples(inputs);
+    
+    let input_names: Vec<&str> = inputs.iter()
+        .map(|(_kind, name)| name.as_str())
+        .collect();
+
+    let builder = make_menu_builder(input_names.clone());
+    // Much more debuggable to populate the model & menu
+    // from a string representation
+    // than add items imperatively
+    let model: gio::MenuModel = builder.get_object("app-menu").unwrap();
+
+    let menu = gtk::Popover::new_from_model(Some(&window), &model);
+    menu.set_pointing_to(&gtk::Rectangle {
+        x: position.x.ceil() as i32,
+        y: position.y.ceil() as i32,
+        width: position.width.floor() as i32,
+        height: position.width.floor() as i32,
+    });
+
+    let initial_state = input_names[current].to_variant();
+
+    let layout_action = gio::SimpleAction::new_stateful(
+        "layout",
+        Some(initial_state.type_()),
+        &initial_state,
+    );
+
+    let action_group = gio::SimpleActionGroup::new();
+    action_group.add_action(&layout_action);
+
+    menu.insert_action_group("popup", Some(&action_group));
+    menu.bind_model(Some(&model), Some("popup"));
+
+    menu.connect_closed(move |_menu| {
+        let state = match layout_action.get_state() {
+            Some(v) => {
+                let s = v.get::<String>().or_else(|| {
+                    eprintln!("Variant is not string: {:?}", v);
+                    None
+                });
+                // FIXME: the `get_state` docs call for unrefing,
+                // but the function is nowhere to be found
+                // glib::Variant::unref(v);
+                s
+            },
+            None => {
+                eprintln!("No variant selected");
+                None
+            },
+        };
+        set_layout("xkb".into(), state.unwrap_or("us".into()));
+    });
+
+    menu.popup();
+}