gecko/browser/components/customizableui/ScrollbarSampler.jsm
Birunthan Mohanathas c831788bcb Bug 1038458 - Part 1: Flatten browser/components/customizableui/src/ directory. r=mak
--HG--
rename : browser/components/customizableui/src/CustomizableUI.jsm => browser/components/customizableui/CustomizableUI.jsm
rename : browser/components/customizableui/src/CustomizableWidgets.jsm => browser/components/customizableui/CustomizableWidgets.jsm
rename : browser/components/customizableui/src/CustomizeMode.jsm => browser/components/customizableui/CustomizeMode.jsm
rename : browser/components/customizableui/src/DragPositionManager.jsm => browser/components/customizableui/DragPositionManager.jsm
rename : browser/components/customizableui/src/PanelWideWidgetTracker.jsm => browser/components/customizableui/PanelWideWidgetTracker.jsm
rename : browser/components/customizableui/src/ScrollbarSampler.jsm => browser/components/customizableui/ScrollbarSampler.jsm
rename : browser/components/customizableui/src/logging.js => browser/components/customizableui/logging.js
2014-07-26 09:31:41 -07:00

71 lines
2.3 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
this.EXPORTED_SYMBOLS = ["ScrollbarSampler"];
const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Promise",
"resource://gre/modules/Promise.jsm");
let gSystemScrollbarWidth = null;
this.ScrollbarSampler = {
getSystemScrollbarWidth: function() {
let deferred = Promise.defer();
if (gSystemScrollbarWidth !== null) {
deferred.resolve(gSystemScrollbarWidth);
return deferred.promise;
}
this._sampleSystemScrollbarWidth().then(function(systemScrollbarWidth) {
gSystemScrollbarWidth = systemScrollbarWidth;
deferred.resolve(gSystemScrollbarWidth);
});
return deferred.promise;
},
resetSystemScrollbarWidth: function() {
gSystemScrollbarWidth = null;
},
_sampleSystemScrollbarWidth: function() {
let deferred = Promise.defer();
let hwin = Services.appShell.hiddenDOMWindow;
let hdoc = hwin.document.documentElement;
let iframe = hwin.document.createElementNS("http://www.w3.org/1999/xhtml",
"html:iframe");
iframe.setAttribute("srcdoc", '<body style="overflow-y: scroll"></body>');
hdoc.appendChild(iframe);
let cwindow = iframe.contentWindow;
let utils = cwindow.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsIDOMWindowUtils);
cwindow.addEventListener("load", function onLoad(aEvent) {
cwindow.removeEventListener("load", onLoad);
let sbWidth = {};
try {
utils.getScrollbarSize(true, sbWidth, {});
} catch(e) {
Cu.reportError("Could not sample scrollbar size: " + e + " -- " +
e.stack);
sbWidth.value = 0;
}
// Minimum width of 10 so that we have enough padding:
sbWidth.value = Math.max(sbWidth.value, 10);
deferred.resolve(sbWidth.value);
iframe.remove();
});
return deferred.promise;
}
};
Object.freeze(this.ScrollbarSampler);