The Tor Browser / file comparison
comparison: browser/components/customizableui/src/ScrollbarSampler.jsm
browser/components/customizableui/src/ScrollbarSampler.jsm
- changeset 1
- ca08bd8f51b2
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| -1:000000000000 | 0:dcdd798b4bb3 |
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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 "use strict"; | |
| 6 | |
| 7 this.EXPORTED_SYMBOLS = ["ScrollbarSampler"]; | |
| 8 | |
| 9 const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components; | |
| 10 | |
| 11 Cu.import("resource://gre/modules/Services.jsm"); | |
| 12 Cu.import("resource://gre/modules/XPCOMUtils.jsm"); | |
| 13 XPCOMUtils.defineLazyModuleGetter(this, "Promise", | |
| 14 "resource://gre/modules/Promise.jsm"); | |
| 15 | |
| 16 let gSystemScrollbarWidth = null; | |
| 17 | |
| 18 this.ScrollbarSampler = { | |
| 19 getSystemScrollbarWidth: function() { | |
| 20 let deferred = Promise.defer(); | |
| 21 | |
| 22 if (gSystemScrollbarWidth !== null) { | |
| 23 deferred.resolve(gSystemScrollbarWidth); | |
| 24 return deferred.promise; | |
| 25 } | |
| 26 | |
| 27 this._sampleSystemScrollbarWidth().then(function(systemScrollbarWidth) { | |
| 28 gSystemScrollbarWidth = systemScrollbarWidth; | |
| 29 deferred.resolve(gSystemScrollbarWidth); | |
| 30 }); | |
| 31 return deferred.promise; | |
| 32 }, | |
| 33 | |
| 34 resetSystemScrollbarWidth: function() { | |
| 35 gSystemScrollbarWidth = null; | |
| 36 }, | |
| 37 | |
| 38 _sampleSystemScrollbarWidth: function() { | |
| 39 let deferred = Promise.defer(); | |
| 40 let hwin = Services.appShell.hiddenDOMWindow; | |
| 41 let hdoc = hwin.document.documentElement; | |
| 42 let iframe = hwin.document.createElementNS("http://www.w3.org/1999/xhtml", | |
| 43 "html:iframe"); | |
| 44 iframe.setAttribute("srcdoc", '<body style="overflow-y: scroll"></body>'); | |
| 45 hdoc.appendChild(iframe); | |
| 46 | |
| 47 let cwindow = iframe.contentWindow; | |
| 48 let utils = cwindow.QueryInterface(Ci.nsIInterfaceRequestor) | |
| 49 .getInterface(Ci.nsIDOMWindowUtils); | |
| 50 | |
| 51 cwindow.addEventListener("load", function onLoad(aEvent) { | |
| 52 cwindow.removeEventListener("load", onLoad); | |
| 53 let sbWidth = {}; | |
| 54 try { | |
| 55 utils.getScrollbarSize(true, sbWidth, {}); | |
| 56 } catch(e) { | |
| 57 Cu.reportError("Could not sample scrollbar size: " + e + " -- " + | |
| 58 e.stack); | |
| 59 sbWidth.value = 0; | |
| 60 } | |
| 61 // Minimum width of 10 so that we have enough padding: | |
| 62 sbWidth.value = Math.max(sbWidth.value, 10); | |
| 63 deferred.resolve(sbWidth.value); | |
| 64 iframe.remove(); | |
| 65 }); | |
| 66 | |
| 67 return deferred.promise; | |
| 68 } | |
| 69 }; | |
| 70 Object.freeze(this.ScrollbarSampler); |
