michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: (function () { // bug 673569 workaround :(
michael@0: 
michael@0: const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
michael@0: 
michael@0: Cu.import("resource://gre/modules/PageThumbs.jsm");
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: 
michael@0: const STATE_LOADING = 1;
michael@0: const STATE_CAPTURING = 2;
michael@0: const STATE_CANCELED = 3;
michael@0: 
michael@0: const backgroundPageThumbsContent = {
michael@0: 
michael@0:   init: function () {
michael@0:     Services.obs.addObserver(this, "document-element-inserted", true);
michael@0: 
michael@0:     // We want a low network priority for this service - lower than b/g tabs
michael@0:     // etc - so set it to the lowest priority available.
michael@0:     this._webNav.QueryInterface(Ci.nsIDocumentLoader).
michael@0:       loadGroup.QueryInterface(Ci.nsISupportsPriority).
michael@0:       priority = Ci.nsISupportsPriority.PRIORITY_LOWEST;
michael@0: 
michael@0:     docShell.allowMedia = false;
michael@0:     docShell.allowPlugins = false;
michael@0:     docShell.allowContentRetargeting = false;
michael@0:     let defaultFlags = Ci.nsIRequest.LOAD_ANONYMOUS |
michael@0:                        Ci.nsIRequest.LOAD_BYPASS_CACHE |
michael@0:                        Ci.nsIRequest.INHIBIT_CACHING |
michael@0:                        Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_HISTORY;
michael@0:     docShell.defaultLoadFlags = defaultFlags;
michael@0: 
michael@0:     addMessageListener("BackgroundPageThumbs:capture",
michael@0:                        this._onCapture.bind(this));
michael@0:     docShell.
michael@0:       QueryInterface(Ci.nsIInterfaceRequestor).
michael@0:       getInterface(Ci.nsIWebProgress).
michael@0:       addProgressListener(this, Ci.nsIWebProgress.NOTIFY_STATE_WINDOW);
michael@0:   },
michael@0: 
michael@0:   observe: function (subj, topic, data) {
michael@0:     // Arrange to prevent (most) popup dialogs for this window - popups done
michael@0:     // in the parent (eg, auth) aren't prevented, but alert() etc are.
michael@0:     // disableDialogs only works on the current inner window, so it has
michael@0:     // to be called every page load, but before scripts run.
michael@0:     if (subj == content.document) {
michael@0:       content.
michael@0:         QueryInterface(Ci.nsIInterfaceRequestor).
michael@0:         getInterface(Ci.nsIDOMWindowUtils).
michael@0:         disableDialogs();
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   get _webNav() {
michael@0:     return docShell.QueryInterface(Ci.nsIWebNavigation);
michael@0:   },
michael@0: 
michael@0:   _onCapture: function (msg) {
michael@0:     this._nextCapture = {
michael@0:       id: msg.data.id,
michael@0:       url: msg.data.url,
michael@0:     };
michael@0:     if (this._currentCapture) {
michael@0:       if (this._state == STATE_LOADING) {
michael@0:         // Cancel the current capture.
michael@0:         this._state = STATE_CANCELED;
michael@0:         this._loadAboutBlank();
michael@0:       }
michael@0:       // Let the current capture finish capturing, or if it was just canceled,
michael@0:       // wait for onStateChange due to the about:blank load.
michael@0:       return;
michael@0:     }
michael@0:     this._startNextCapture();
michael@0:   },
michael@0: 
michael@0:   _startNextCapture: function () {
michael@0:     if (!this._nextCapture)
michael@0:       return;
michael@0:     this._currentCapture = this._nextCapture;
michael@0:     delete this._nextCapture;
michael@0:     this._state = STATE_LOADING;
michael@0:     this._currentCapture.pageLoadStartDate = new Date();
michael@0:     this._webNav.loadURI(this._currentCapture.url,
michael@0:                          Ci.nsIWebNavigation.LOAD_FLAGS_STOP_CONTENT,
michael@0:                          null, null, null);
michael@0:   },
michael@0: 
michael@0:   onStateChange: function (webProgress, req, flags, status) {
michael@0:     if (webProgress.isTopLevel &&
michael@0:         (flags & Ci.nsIWebProgressListener.STATE_STOP) &&
michael@0:         this._currentCapture) {
michael@0:       if (req.name == "about:blank") {
michael@0:         if (this._state == STATE_CAPTURING) {
michael@0:           // about:blank has loaded, ending the current capture.
michael@0:           this._finishCurrentCapture();
michael@0:           delete this._currentCapture;
michael@0:           this._startNextCapture();
michael@0:         }
michael@0:         else if (this._state == STATE_CANCELED) {
michael@0:           // A capture request was received while the current capture's page
michael@0:           // was still loading.
michael@0:           delete this._currentCapture;
michael@0:           this._startNextCapture();
michael@0:         }
michael@0:       }
michael@0:       else if (this._state == STATE_LOADING) {
michael@0:         // The requested page has loaded.  Capture it.
michael@0:         this._state = STATE_CAPTURING;
michael@0:         this._captureCurrentPage();
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _captureCurrentPage: function () {
michael@0:     let capture = this._currentCapture;
michael@0:     capture.finalURL = this._webNav.currentURI.spec;
michael@0:     capture.pageLoadTime = new Date() - capture.pageLoadStartDate;
michael@0: 
michael@0:     let canvas = PageThumbs._createCanvas(content);
michael@0:     let canvasDrawDate = new Date();
michael@0:     PageThumbs._captureToCanvas(content, canvas);
michael@0:     capture.canvasDrawTime = new Date() - canvasDrawDate;
michael@0: 
michael@0:     canvas.toBlob(blob => {
michael@0:       capture.imageBlob = blob;
michael@0:       // Load about:blank to finish the capture and wait for onStateChange.
michael@0:       this._loadAboutBlank();
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   _finishCurrentCapture: function () {
michael@0:     let capture = this._currentCapture;
michael@0:     let fileReader = Cc["@mozilla.org/files/filereader;1"].
michael@0:                      createInstance(Ci.nsIDOMFileReader);
michael@0:     fileReader.onloadend = () => {
michael@0:       sendAsyncMessage("BackgroundPageThumbs:didCapture", {
michael@0:         id: capture.id,
michael@0:         imageData: fileReader.result,
michael@0:         finalURL: capture.finalURL,
michael@0:         telemetry: {
michael@0:           CAPTURE_PAGE_LOAD_TIME_MS: capture.pageLoadTime,
michael@0:           CAPTURE_CANVAS_DRAW_TIME_MS: capture.canvasDrawTime,
michael@0:         },
michael@0:       });
michael@0:     };
michael@0:     fileReader.readAsArrayBuffer(capture.imageBlob);
michael@0:   },
michael@0: 
michael@0:   // We load about:blank to finish all captures, even canceled captures.  Two
michael@0:   // reasons: GC the captured page, and ensure it can't possibly load any more
michael@0:   // resources.
michael@0:   _loadAboutBlank: function _loadAboutBlank() {
michael@0:     this._webNav.loadURI("about:blank",
michael@0:                          Ci.nsIWebNavigation.LOAD_FLAGS_STOP_CONTENT,
michael@0:                          null, null, null);
michael@0:   },
michael@0: 
michael@0:   QueryInterface: XPCOMUtils.generateQI([
michael@0:     Ci.nsIWebProgressListener,
michael@0:     Ci.nsISupportsWeakReference,
michael@0:     Ci.nsIObserver,
michael@0:   ]),
michael@0: };
michael@0: 
michael@0: backgroundPageThumbsContent.init();
michael@0: 
michael@0: })();