Verified Commit 85e237f6 authored by ma1's avatar ma1 Committed by Pier Angelo Vendrame
Browse files

Bug 41631: Prevent weird initial window dimensions caused by subpixel computations

parent c78671b4

toolkit/components/resistfingerprinting/RFPHelper.sys.mjs

+63 −45
Original line number Diff line number Diff line
@@ -16,16 +16,31 @@ const kPrefLetterboxingTesting = 
  "privacy.resistFingerprinting.letterboxing.testing";

const kTopicDOMWindowOpened = "domwindowopened";



var logConsole;

function log(msg) {

  if (!logConsole) {

    logConsole = console.createInstance({

const lazy = {};



XPCOMUtils.defineLazyGetter(lazy, "logConsole", () =>

  console.createInstance({

    prefix: "RFPHelper.jsm",

    maxLogLevelPref: "privacy.resistFingerprinting.jsmloglevel",

    });

  })

);



function log(...args) {

  lazy.logConsole.log(...args);

}



  logConsole.log(msg);

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 {
@@ -154,7 +169,11 @@ 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();

    }

  }
@@ -291,12 +310,12 @@ 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));

    }

  }
@@ -398,11 +417,13 @@ class _RFPHelper { 
    let logPrefix = `_roundContentSize[${Math.random()}]`;

    log(logPrefix);

    let win = aBrowser.ownerGlobal;



    let browserContainer = aBrowser

      .getTabBrowser()

      .getBrowserContainer(aBrowser);

    let browserParent = aBrowser.parentElement;

    browserParent.classList.remove("exclude-letterboxing");



    let [

      [contentWidth, contentHeight],

      [parentWidth, parentHeight],
@@ -415,6 +436,22 @@ class _RFPHelper { 
      ])

    );



    if (!win._rfpSizeOffset) {

      const BASELINE_ROUNDING = 10;

      const offset = s =>

        s - Math.round(s / BASELINE_ROUNDING) * BASELINE_ROUNDING;



      win._rfpSizeOffset = {

        width: offset(parentWidth),

        height: offset(parentHeight),

      };

      log(

        `${logPrefix} Window size offsets %o (from %s, %s)`,

        win._rfpSizeOffset,

        parentWidth,

        parentHeight

      );

    }

    log(

      `${logPrefix} contentWidth=${contentWidth} contentHeight=${contentHeight} parentWidth=${parentWidth} parentHeight=${parentHeight} containerWidth=${containerWidth} containerHeight=${containerHeight}${

        isNewTab ? " (new tab)." : "."
@@ -433,6 +470,16 @@ class _RFPHelper { 
      });



      let result;



      if (!this.letterboxingEnabled) {

        const offset = win._rfpSizeOffset;

        result = r(aWidth - offset.width, aHeight - offset.height);

        log(

          `${logPrefix} Letterboxing disabled, applying baseline rounding offsets: (${aWidth}, ${aHeight}) => ${result.width} x ${result.height})`

        );

        return result;

      }



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

      // If the set is empty, we will round the content with the default

      // stepping size.
@@ -493,7 +540,7 @@ class _RFPHelper { 
            try {

              change();

            } catch (e) {

              logConsole.error(e);

              lazy.logConsole.error(e);

            }

          }

        });
@@ -550,7 +597,6 @@ class _RFPHelper { 


  _updateSizeForTabsInWindow(aWindow) {

    let tabBrowser = aWindow.gBrowser;



    tabBrowser.tabpanels?.classList.add("letterboxing");



    for (let tab of tabBrowser.tabs) {
@@ -580,20 +626,6 @@ 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);
@@ -611,20 +643,6 @@ 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;