Files
tubestation/toolkit/components/thumbnails/content/backgroundPageThumbsContent.js

120 lines
4.2 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/. */
(function () { // bug 673569 workaround :(
const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
Cu.import("resource://gre/modules/PageThumbs.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");
const backgroundPageThumbsContent = {
init: function () {
Services.obs.addObserver(this, "document-element-inserted", true);
// We want a low network priority for this service - lower than b/g tabs
// etc - so set it to the lowest priority available.
this._webNav.QueryInterface(Ci.nsIDocumentLoader).
loadGroup.QueryInterface(Ci.nsISupportsPriority).
priority = Ci.nsISupportsPriority.PRIORITY_LOWEST;
docShell.allowMedia = false;
docShell.allowPlugins = false;
docShell.allowContentRetargeting = false;
let defaultFlags = Ci.nsIRequest.LOAD_ANONYMOUS |
Ci.nsIRequest.LOAD_BYPASS_CACHE |
Ci.nsIRequest.INHIBIT_CACHING |
Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_HISTORY;
docShell.defaultLoadFlags = defaultFlags;
addMessageListener("BackgroundPageThumbs:capture",
this._onCapture.bind(this));
docShell.
QueryInterface(Ci.nsIInterfaceRequestor).
getInterface(Ci.nsIWebProgress).
addProgressListener(this, Ci.nsIWebProgress.NOTIFY_STATE_WINDOW);
},
observe: function (subj, topic, data) {
// Arrange to prevent (most) popup dialogs for this window - popups done
// in the parent (eg, auth) aren't prevented, but alert() etc are.
// preventFurtherDialogs only works on the current inner window, so it has
// to be called every page load, but before scripts run.
if (subj == content.document) {
content.
QueryInterface(Ci.nsIInterfaceRequestor).
getInterface(Ci.nsIDOMWindowUtils).
preventFurtherDialogs();
}
},
get _webNav() {
return docShell.QueryInterface(Ci.nsIWebNavigation);
},
_onCapture: function (msg) {
this._webNav.loadURI(msg.json.url,
Ci.nsIWebNavigation.LOAD_FLAGS_STOP_CONTENT,
null, null, null);
// If a page was already loading, onStateChange is synchronously called at
// this point by loadURI.
this._requestID = msg.json.id;
this._requestDate = new Date();
},
onStateChange: function (webProgress, req, flags, status) {
if (!webProgress.isTopLevel ||
!(flags & Ci.nsIWebProgressListener.STATE_STOP) ||
req.name == "about:blank")
return;
let requestID = this._requestID;
let pageLoadTime = new Date() - this._requestDate;
delete this._requestID;
let canvas = PageThumbs._createCanvas(content);
let captureDate = new Date();
PageThumbs._captureToCanvas(content, canvas);
let captureTime = new Date() - captureDate;
let finalURL = this._webNav.currentURI.spec;
let fileReader = Cc["@mozilla.org/files/filereader;1"].
createInstance(Ci.nsIDOMFileReader);
fileReader.onloadend = () => {
sendAsyncMessage("BackgroundPageThumbs:didCapture", {
id: requestID,
imageData: fileReader.result,
finalURL: finalURL,
telemetry: {
CAPTURE_PAGE_LOAD_TIME_MS: pageLoadTime,
CAPTURE_CANVAS_DRAW_TIME_MS: captureTime,
},
});
};
canvas.toBlob(blob => fileReader.readAsArrayBuffer(blob));
// If no other pages are loading, load about:blank to cause the captured
// window to be collected... eventually. Calling loadURI at this point
// trips an assertion in nsLoadGroup::Cancel, so do it on another stack.
Services.tm.mainThread.dispatch(() => {
if (!("_requestID" in this))
this._webNav.loadURI("about:blank",
Ci.nsIWebNavigation.LOAD_FLAGS_STOP_CONTENT,
null, null, null);
}, Ci.nsIEventTarget.DISPATCH_NORMAL);
},
QueryInterface: XPCOMUtils.generateQI([
Ci.nsIWebProgressListener,
Ci.nsISupportsWeakReference,
Ci.nsIObserver,
]),
};
backgroundPageThumbsContent.init();
})();