BB 41631: Prevent weird initial window dimensions caused by subpixel computations (89256ce8) · Commits · jwilde / Mullvad Browser

toolkit/components/resistfingerprinting/RFPHelper.sys.mjs

+80 −35

Original line number	Diff line number	Diff line
		@@ -35,6 +35,20 @@ function log(...args) {
		lazy.logConsole.log(...args);
		}

		function forEachWindow(callback) {
		const windowList = Services.wm.getEnumerator("navigator:browser");
		while (windowList.hasMoreElements()) {
		const win = windowList.getNext();
		if (win.gBrowser && !win.closed) {
		try {
		callback(win);
		} catch (e) {
		lazy.logConsole.error(e);
		}
		}
		}
		}

		class _RFPHelper {
		// ============================================================================
		// Shared Setup
		@@ -202,7 +216,11 @@ class _RFPHelper {
		(this.rfpEnabled = Services.prefs.getBoolPref(kPrefResistFingerprinting))
		) {
		this._addRFPObservers();
		Services.ww.registerNotification(this);
		forEachWindow(win => this._attachWindow(win));
		} else {
		forEachWindow(win => this._detachWindow(win));
		Services.ww.unregisterNotification(this);
		this._removeRFPObservers();
		}
		}
		@@ -334,12 +352,12 @@ class _RFPHelper {
		}

		_handleLetterboxingPrefChanged() {
		if (Services.prefs.getBoolPref(kPrefLetterboxing, false)) {
		Services.ww.registerNotification(this);
		this._attachAllWindows();
		} else {
		this._detachAllWindows();
		Services.ww.unregisterNotification(this);
		this.letterboxingEnabled = Services.prefs.getBoolPref(
		kPrefLetterboxing,
		false
		);
		if (this.rfpEnabled) {
		forEachWindow(win => this._updateSizeForTabsInWindow(win));
		}
		}

		@@ -458,6 +476,17 @@ class _RFPHelper {
		])
		);

		const isInitialSize =
		win._rfpOriginalSize &&
		win.outerWidth === win._rfpOriginalSize.width &&
		win.outerHeight === win._rfpOriginalSize.height;

		// We may need to shrink this window to rounded size if the browser container
		// area is taller than the original, meaning extra chrome (like the optional
		// "Only Show on New Tab" bookmarks toobar) was present and now gone.
		const needToShrink =
		isInitialSize && containerHeight > win._rfpOriginalSize.containerHeight;

		log(
		`${logPrefix} contentWidth=${contentWidth} contentHeight=${contentHeight} parentWidth=${parentWidth} parentHeight=${parentHeight} containerWidth=${containerWidth} containerHeight=${containerHeight}${
		isNewTab ? " (new tab)." : "."
		@@ -485,7 +514,10 @@ class _RFPHelper {

		log(`${logPrefix} roundDimensions(${aWidth}, ${aHeight})`);

		let result;
		if (!(isInitialSize \|\| this.letterboxingEnabled)) {
		// just round size to int
		return r(aWidth, aHeight);
		}

		// If the set is empty, we will round the content with the default
		// stepping size.
		@@ -540,6 +572,17 @@ class _RFPHelper {
		lazy.logConsole.error(e);
		}
		}
		if (needToShrink && win.shrinkToLetterbox()) {
		win.addEventListener(
		"resize",
		() => {
		// We need to record the "new" initial size in this listener
		// because resized dimensions are not immediately available.
		RFPHelper._recordWindowSize(win);
		},
		{ once: true }
		);
		}
		});
		},
		});
		@@ -638,9 +681,39 @@ class _RFPHelper {
		// we need to add this class late because otherwise new windows get maximized
		aWindow.setTimeout(() => {
		tabBrowser.tabpanels?.classList.add("letterboxing-ready");
		if (!aWindow._rfpOriginalSize) {
		this._recordWindowSize(aWindow);
		}
		});
		}

		_recordWindowSize(aWindow) {
		aWindow.promiseDocumentFlushed(() => {
		aWindow._rfpOriginalSize = {
		width: aWindow.outerWidth,
		height: aWindow.outerHeight,
		containerHeight: aWindow.gBrowser.getBrowserContainer()?.clientHeight,
		};
		log("Recording original window size", aWindow._rfpOriginalSize);
		});
		}

		// We will attach this method to each browser window. When called
		// it will instantly resize the window to exactly fit the selected
		// (possibly letterboxed) browser.
		// Returns true if a window resize will occur, false otherwise.
		shrinkToLetterbox() {
		let { selectedBrowser } = this.gBrowser;
		let stack = selectedBrowser.closest(".browserStack");
		const outer = stack.getBoundingClientRect();
		const inner = selectedBrowser.getBoundingClientRect();
		if (inner.width !== outer.witdh \|\| inner.height !== outer.height) {
		this.resizeBy(inner.width - outer.width, inner.height - outer.height);
		return true;
		}
		return false;
		}

		_attachWindow(aWindow) {
		aWindow.gBrowser.addTabsProgressListener(this);
		aWindow.addEventListener("TabOpen", this);
		@@ -658,20 +731,6 @@ class _RFPHelper {
		this._updateSizeForTabsInWindow(aWindow);
		}

		_attachAllWindows() {
		let windowList = Services.wm.getEnumerator("navigator:browser");

		while (windowList.hasMoreElements()) {
		let win = windowList.getNext();

		if (win.closed \|\| !win.gBrowser) {
		continue;
		}

		this._attachWindow(win);
		}
		}

		_detachWindow(aWindow) {
		let tabBrowser = aWindow.gBrowser;
		tabBrowser.removeTabsProgressListener(this);
		@@ -689,20 +748,6 @@ class _RFPHelper {
		}
		}

		_detachAllWindows() {
		let windowList = Services.wm.getEnumerator("navigator:browser");

		while (windowList.hasMoreElements()) {
		let win = windowList.getNext();

		if (win.closed \|\| !win.gBrowser) {
		continue;
		}

		this._detachWindow(win);
		}
		}

		_handleDOMWindowOpened(win) {
		let self = this;