1 files changed, 91 insertions, 0 deletions
diff --git a/js/ui/focusCaretTracker.js b/js/ui/focusCaretTracker.js
new file mode 100644
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+++ b/js/ui/focusCaretTracker.js
@@ -0,0 +1,91 @@
+/** -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+ * Copyright 2012 Inclusive Design Research Centre, OCAD University.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author:
+ *   Joseph Scheuhammer <clown@alum.mit.edu>
+ * Contributor:
+ *   Magdalen Berns <m.berns@sms.ed.ac.uk>
+ */
+/* exported FocusCaretTracker */
+
+const Atspi = imports.gi.Atspi;
+const Signals = imports.misc.signals;
+
+const CARETMOVED        = 'object:text-caret-moved';
+const STATECHANGED      = 'object:state-changed';
+
+var FocusCaretTracker = class FocusCaretTracker extends Signals.EventEmitter {
+    constructor() {
+        super();
+
+        this._atspiListener = Atspi.EventListener.new(this._onChanged.bind(this));
+
+        this._atspiInited = false;
+        this._focusListenerRegistered = false;
+        this._caretListenerRegistered = false;
+    }
+
+    _onChanged(event) {
+        if (event.type.indexOf(STATECHANGED) == 0)
+            this.emit('focus-changed', event);
+        else if (event.type == CARETMOVED)
+            this.emit('caret-moved', event);
+    }
+
+    _initAtspi() {
+        if (!this._atspiInited && Atspi.init() == 0) {
+            Atspi.set_timeout(250, 250);
+            this._atspiInited = true;
+        }
+
+        return this._atspiInited;
+    }
+
+    registerFocusListener() {
+        if (!this._initAtspi() || this._focusListenerRegistered)
+            return;
+
+        this._atspiListener.register(`${STATECHANGED}:focused`);
+        this._atspiListener.register(`${STATECHANGED}:selected`);
+        this._focusListenerRegistered = true;
+    }
+
+    registerCaretListener() {
+        if (!this._initAtspi() || this._caretListenerRegistered)
+            return;
+
+        this._atspiListener.register(CARETMOVED);
+        this._caretListenerRegistered = true;
+    }
+
+    deregisterFocusListener() {
+        if (!this._focusListenerRegistered)
+            return;
+
+        this._atspiListener.deregister(`${STATECHANGED}:focused`);
+        this._atspiListener.deregister(`${STATECHANGED}:selected`);
+        this._focusListenerRegistered = false;
+    }
+
+    deregisterCaretListener() {
+        if (!this._caretListenerRegistered)
+            return;
+
+        this._atspiListener.deregister(CARETMOVED);
+        this._caretListenerRegistered = false;
+    }
+};