GUACAMOLE-352: Allow additional elements to be added to a single Guacamole.Keyboard.

guacamole-common-js/src/main/webapp/modules/Keyboard.js

@@ -25,9 +25,12 @@ var Guacamole = Guacamole || {};
  * which represent keys as their corresponding X11 keysym.
  * 
  * @constructor
- * @param {Element} element The Element to use to provide keyboard events.
+ * @param {Element} [element]
+ *    The Element to use to provide keyboard events. If omitted, at least one
+ *    Element must be manually provided through the listenTo() function for
+ *    the Guacamole.Keyboard instance to have any effect.
  */
-Guacamole.Keyboard = function(element) {
+Guacamole.Keyboard = function Keyboard(element) {
 
     /**
      * Reference to this Guacamole.Keyboard.
@@ -35,6 +38,25 @@ Guacamole.Keyboard = function(element) {
      */
     var guac_keyboard = this;
 
+    /**
+     * An integer value which uniquely identifies this Guacamole.Keyboard
+     * instance with respect to other Guacamole.Keyboard instances.
+     *
+     * @private
+     * @type {Number}
+     */
+    var guacKeyboardID = Guacamole.Keyboard._nextID++;
+
+    /**
+     * The name of the property which is added to event objects via markEvent()
+     * to note that they have already been handled by this Guacamole.Keyboard.
+     *
+     * @private
+     * @constant
+     * @type {String}
+     */
+    var EVENT_MARKER = '_GUAC_KEYBOARD_HANDLED_BY_' + guacKeyboardID;
+
     /**
      * Fired whenever the user presses a key with the element associated
      * with this Guacamole.Keyboard in focus.
@@ -1134,12 +1156,51 @@ Guacamole.Keyboard = function(element) {
 
     };
 
+    /**
+     * Attempts to mark the given Event as having been handled by this
+     * Guacamole.Keyboard. If the Event has already been marked as handled,
+     * false is returned.
+     *
+     * @param {Event} e
+     *     The Event to mark.
+     *
+     * @returns {Boolean}
+     *     true if the given Event was successfully marked, false if the given
+     *     Event was already marked.
+     */
+    var markEvent = function markEvent(e) {
+
+        // Fail if event is already marked
+        if (e[EVENT_MARKER])
+            return false;
+
+        // Mark event otherwise
+        e[EVENT_MARKER] = true;
+        return true;
+
+    };
+
+    /**
+     * Attaches event listeners to the given Element, automatically translating
+     * received key, input, and composition events into simple keydown/keyup
+     * events signalled through this Guacamole.Keyboard's onkeydown and
+     * onkeyup handlers.
+     *
+     * @param {Element} element
+     *     The Element to attach event listeners to for the sake of handling
+     *     key or input events.
+     */
+    this.listenTo = function listenTo(element) {
+
         // When key pressed
         element.addEventListener("keydown", function(e) {
 
             // Only intercept if handler set
             if (!guac_keyboard.onkeydown) return;
 
+            // Ignore events which have already been handled
+            if (!markEvent(e)) return;
+
             var keyCode;
             if (window.event) keyCode = window.event.keyCode;
             else if (e.which) keyCode = e.which;
@@ -1168,6 +1229,9 @@ Guacamole.Keyboard = function(element) {
             // Only intercept if handler set
             if (!guac_keyboard.onkeydown && !guac_keyboard.onkeyup) return;
 
+            // Ignore events which have already been handled
+            if (!markEvent(e)) return;
+
             var charCode;
             if (window.event) charCode = window.event.keyCode;
             else if (e.which) charCode = e.which;
@@ -1191,6 +1255,9 @@ Guacamole.Keyboard = function(element) {
             // Only intercept if handler set
             if (!guac_keyboard.onkeyup) return;
 
+            // Ignore events which have already been handled
+            if (!markEvent(e)) return;
+
             e.preventDefault();
 
             var keyCode;
@@ -1221,9 +1288,12 @@ Guacamole.Keyboard = function(element) {
             // Only intercept if handler set
             if (!guac_keyboard.onkeydown && !guac_keyboard.onkeyup) return;
 
+            // Ignore events which have already been handled
+            if (!markEvent(e)) return;
+
             // Type all content written
             if (e.data && !e.isComposing) {
-            element.removeEventListener("compositionend", handleComposition, false);
+                element.removeEventListener("compositionend", handleComposition, true);
                 guac_keyboard.type(e.data);
             }
 
@@ -1244,20 +1314,38 @@ Guacamole.Keyboard = function(element) {
             // Only intercept if handler set
             if (!guac_keyboard.onkeydown && !guac_keyboard.onkeyup) return;
 
+            // Ignore events which have already been handled
+            if (!markEvent(e)) return;
+
             // Type all content written
             if (e.data) {
-            element.removeEventListener("input", handleInput, false);
+                element.removeEventListener("input", handleInput, true);
                 guac_keyboard.type(e.data);
             }
 
         };
 
-    // Automatically type text entered into the wrapped element
-    element.addEventListener("input", handleInput, false);
-    element.addEventListener("compositionend", handleComposition, false);
+        // Automatically type text entered into the wrapped field
+        element.addEventListener("input", handleInput, true);
+        element.addEventListener("compositionend", handleComposition, true);
+
+    };
+
+    // Listen to given element, if any
+    if (element)
+        guac_keyboard.listenTo(element);
 
 };
 
+/**
+ * The unique numerical identifier to assign to the next Guacamole.Keyboard
+ * instance.
+ *
+ * @private
+ * @type {Number}
+ */
+Guacamole.Keyboard._nextID = 0;
+
 /**
  * The state of all supported keyboard modifiers.
  * @constructor