InputSourceを素早く切り替えたり、特定のウインドウでは何もしないような gnome-shell extension。以前のよくあるIMの動作を再現する。gnome-shell-extension-tool -c で作って、xmlはschemasディレクトリを作ってglib-compile-schemas schemasとかでコンパイルする感じで。

extension.js

// -*- coding: utf-8; -*-
// for gnome-shell 3.16.2

const Gio = imports.gi.Gio;
const Shell = imports.gi.Shell;
const Meta = imports.gi.Meta;

const St = imports.gi.St;
const Main = imports.ui.main;
const ExtensionUtils = imports.misc.extensionUtils;

function getSettings(schema) {
	let extension = ExtensionUtils.getCurrentExtension();

	schema = schema || extension.metadata['settings-schema'];

	const GioSSS = Gio.SettingsSchemaSource;

	let schemaDir = extension.dir.get_child('schemas');
	let schemaSource;
	if (schemaDir.query_exists(null))
		schemaSource = GioSSS.new_from_directory(schemaDir.get_path(),
												 GioSSS.get_default(),
												 false);
	else
		schemaSource = GioSSS.get_default();

	let schemaObj = schemaSource.lookup(schema, true);
	if (!schemaObj)
		throw new Error('Schema ' + schema + ' could not be found for extension '
						+ extension.metadata.uuid + '. Please check your installation.');

	return new Gio.Settings({ settings_schema: schemaObj });
}


// Event handlers for InputSources

function _switchInputSource(display, screen, window, binding) {
	//log("SwitchInputSource!");
	// hard coding!!
	var ism = Main.panel.statusArea.keyboard._inputSourceManager;

	var current = ism.currentSource;
	var sources = ism.inputSources;
	for (var i in sources) {
		if (sources[i] != current) {
			sources[i].activate();
			break;
		}
	}
}


// Binding and Unbinding

let enabledFlag = false;

function _enable() {
	//log(">> Enable");
	if (!enabledFlag) {
		try {
			Main.wm.addKeybinding(
				'custom-switch-is-key',
				getSettings("org.gnome.shell.extensions.custom-switch-is"),
				Meta.KeyBindingFlags.IS_REVERSED,
				Shell.ActionMode.ALL,_switchInputSource);
			//log(">> Enable OK");
		} catch (e) {
			log(e.message);
		} finally {
			enabledFlag = true;
		}
	}
}

function _disable() {
	//log(">> Disable");
	try {
		Main.wm.removeKeybinding('custom-switch-is-key');
	} catch (e) {
		log(e.message);
	} finally {
		enabledFlag = false;
	}
}

function _windowsRestacked() {
	if (!Main.overview.visible || Main.overview.animationInProgress) {
		if (global.display.focus_window && global.display.focus_window.get_wm_class() == "Emacs") {
			_disable();
		} else {
			_enable();
		}
	} else {
		_enable();
	}
}


// Initialize and Cleanup

let initState = null;

function _init() {
	if (initState) return;
	initState = {};
	initState.idRestacked = global.screen.connect('restacked', _windowsRestacked);
}

function _cleanup() {
	if (!initState) return;

	global.screen.disconnect(initState.idRestacked);

	initState = null;
}



function init() {
	// do nothing
}

function enable() {
	_init();
	_enable();
}

function disable() {
	_disable();
	_cleanup();
}

org.gnome.shell.extensions.custom-switch-is.gschema.xml

<?xml version="1.0" encoding="UTF-8"?>
<schemalist gettext-domain="gnome-shell-extensions">
  <schema path="/org/gnome/shell/extensions/custom-switch-is/" id="org.gnome.shell.extensions.custom-switch-is">
    <key type="as" name="custom-switch-is-key">
      <default><![CDATA[['<Control>o']]]></default>
      <summary>Switch InputSource Key</summary>
    </key>
  </schema>
</schemalist>