chrome/browser/resources/uber/uber_utils.js

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @fileoverview A collection of utility methods for UberPage and its contained
   7  *     pages.
   8  */
   9
  10 cr.define('uber', function() {
  11   /**
  12    * Fixed position header elements on the page to be shifted by handleScroll.
  13    * @type {NodeList}
  14    */
  15   var headerElements;
  16
  17   /**
  18    * This should be called by uber content pages when DOM content has loaded.
  19    */
  20   function onContentFrameLoaded() {
  21     headerElements = document.getElementsByTagName('header');
  22     document.addEventListener('scroll', handleScroll);
  23     document.addEventListener('mousedown', handleMouseDownInFrame, true);
  24
  25     invokeMethodOnParent('ready');
  26
  27     // Prevent the navigation from being stuck in a disabled state when a
  28     // content page is reloaded while an overlay is visible (crbug.com/246939).
  29     invokeMethodOnParent('stopInterceptingEvents');
  30
  31     // Trigger the scroll handler to tell the navigation if our page started
  32     // with some scroll (happens when you use tab restore).
  33     handleScroll();
  34
  35     window.addEventListener('message', handleWindowMessage);
  36   }
  37
  38   /**
  39    * Handles scroll events on the document. This adjusts the position of all
  40    * headers and updates the parent frame when the page is scrolled.
  41    */
  42   function handleScroll() {
  43     var scrollLeft = scrollLeftForDocument(document);
  44     var offset = scrollLeft * -1;
  45     for (var i = 0; i < headerElements.length; i++) {
  46       // As a workaround for http://crbug.com/231830, set the transform to
  47       // 'none' rather than 0px.
  48       headerElements[i].style.webkitTransform = offset ?
  49           'translateX(' + offset + 'px)' : 'none';
  50     }
  51
  52     invokeMethodOnParent('adjustToScroll', scrollLeft);
  53   }
  54
  55   /**
  56    * Tells the parent to focus the current frame if the mouse goes down in the
  57    * current frame (and it doesn't already have focus).
  58    * @param {Event} e A mousedown event.
  59    */
  60   function handleMouseDownInFrame(e) {
  61     if (!e.isSynthetic && !document.hasFocus())
  62       window.focus();
  63   }
  64
  65   /**
  66    * Handles 'message' events on window.
  67    * @param {Event} e The message event.
  68    */
  69   function handleWindowMessage(e) {
  70     e = /** @type {!MessageEvent<!{method: string, params: *}>} */(e);
  71     if (e.data.method === 'frameSelected') {
  72       handleFrameSelected();
  73     } else if (e.data.method === 'mouseWheel') {
  74       handleMouseWheel(
  75           /** @type {{deltaX: number, deltaY: number}} */(e.data.params));
  76     } else if (e.data.method === 'mouseDown') {
  77       handleMouseDown();
  78     } else if (e.data.method === 'popState') {
  79       handlePopState(e.data.params.state, e.data.params.path);
  80     }
  81   }
  82
  83   /**
  84    * This is called when a user selects this frame via the navigation bar
  85    * frame (and is triggered via postMessage() from the uber page).
  86    */
  87   function handleFrameSelected() {
  88     setScrollTopForDocument(document, 0);
  89   }
  90
  91   /**
  92    * Called when a user mouse wheels (or trackpad scrolls) over the nav frame.
  93    * The wheel event is forwarded here and we scroll the body.
  94    * There's no way to figure out the actual scroll amount for a given delta.
  95    * It differs for every platform and even initWebKitWheelEvent takes a
  96    * pixel amount instead of a wheel delta. So we just choose something
  97    * reasonable and hope no one notices the difference.
  98    * @param {{deltaX: number, deltaY: number}} params A structure that holds
  99    *     wheel deltas in X and Y.
 100    */
 101   function handleMouseWheel(params) {
 102     window.scrollBy(-params.deltaX * 49 / 120, -params.deltaY * 49 / 120);
 103   }
 104
 105   /**
 106    * Fire a synthetic mousedown on the body to dismiss transient things like
 107    * bubbles or menus that listen for mouse presses outside of their UI. We
 108    * dispatch a fake mousedown rather than a 'mousepressedinnavframe' so that
 109    * settings/history/extensions don't need to know about their embedder.
 110    */
 111   function handleMouseDown() {
 112     var mouseEvent = new MouseEvent('mousedown');
 113     mouseEvent.isSynthetic = true;
 114     document.dispatchEvent(mouseEvent);
 115   }
 116
 117   /**
 118    * Called when the parent window restores some state saved by uber.pushState
 119    * or uber.replaceState. Simulates a popstate event.
 120    * @param {PopStateEvent} state A state object for replaceState and pushState.
 121    * @param {string} path The path the page navigated to.
 122    * @suppress {checkTypes}
 123    */
 124   function handlePopState(state, path) {
 125     window.history.replaceState(state, '', path);
 126     window.dispatchEvent(new PopStateEvent('popstate', {state: state}));
 127   }
 128
 129   /**
 130    * @return {boolean} Whether this frame has a parent.
 131    */
 132   function hasParent() {
 133     return window != window.parent;
 134   }
 135
 136   /**
 137    * Invokes a method on the parent window (UberPage). This is a convenience
 138    * method for API calls into the uber page.
 139    * @param {string} method The name of the method to invoke.
 140    * @param {?=} opt_params Optional property bag of parameters to pass to the
 141    *     invoked method.
 142    */
 143   function invokeMethodOnParent(method, opt_params) {
 144     if (!hasParent())
 145       return;
 146
 147     invokeMethodOnWindow(window.parent, method, opt_params, 'chrome://chrome');
 148   }
 149
 150   /**
 151    * Invokes a method on the target window.
 152    * @param {string} method The name of the method to invoke.
 153    * @param {?=} opt_params Optional property bag of parameters to pass to the
 154    *     invoked method.
 155    * @param {string=} opt_url The origin of the target window.
 156    */
 157   function invokeMethodOnWindow(targetWindow, method, opt_params, opt_url) {
 158     var data = {method: method, params: opt_params};
 159     targetWindow.postMessage(data, opt_url ? opt_url : '*');
 160   }
 161
 162   /**
 163    * Updates the page's history state. If the page is embedded in a child,
 164    * forward the information to the parent for it to manage history for us. This
 165    * is a replacement of history.replaceState and history.pushState.
 166    * @param {Object} state A state object for replaceState and pushState.
 167    * @param {string} path The path the page navigated to.
 168    * @param {boolean} replace If true, navigate with replacement.
 169    */
 170   function updateHistory(state, path, replace) {
 171     var historyFunction = replace ?
 172         window.history.replaceState :
 173         window.history.pushState;
 174
 175     if (hasParent()) {
 176       // If there's a parent, always replaceState. The parent will do the actual
 177       // pushState.
 178       historyFunction = window.history.replaceState;
 179       invokeMethodOnParent('updateHistory', {
 180         state: state, path: path, replace: replace});
 181     }
 182     historyFunction.call(window.history, state, '', '/' + path);
 183   }
 184
 185   /**
 186    * Sets the current title for the page. If the page is embedded in a child,
 187    * forward the information to the parent. This is a replacement for setting
 188    * document.title.
 189    * @param {string} title The new title for the page.
 190    */
 191   function setTitle(title) {
 192     document.title = title;
 193     invokeMethodOnParent('setTitle', {title: title});
 194   }
 195
 196   /**
 197    * Pushes new history state for the page. If the page is embedded in a child,
 198    * forward the information to the parent; when embedded, all history entries
 199    * are attached to the parent. This is a replacement of history.pushState.
 200    * @param {Object} state A state object for replaceState and pushState.
 201    * @param {string} path The path the page navigated to.
 202    */
 203   function pushState(state, path) {
 204     updateHistory(state, path, false);
 205   }
 206
 207   /**
 208    * Replaces the page's history state. If the page is embedded in a child,
 209    * forward the information to the parent; when embedded, all history entries
 210    * are attached to the parent. This is a replacement of history.replaceState.
 211    * @param {Object} state A state object for replaceState and pushState.
 212    * @param {string} path The path the page navigated to.
 213    */
 214   function replaceState(state, path) {
 215     updateHistory(state, path, true);
 216   }
 217
 218   return {
 219     invokeMethodOnParent: invokeMethodOnParent,
 220     invokeMethodOnWindow: invokeMethodOnWindow,
 221     onContentFrameLoaded: onContentFrameLoaded,
 222     pushState: pushState,
 223     replaceState: replaceState,
 224     setTitle: setTitle,
 225   };
 226 });