gecko-dev/dom/base/nsScreen.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */

#include "mozilla/dom/Event.h" // for nsIDOMEvent::InternalDOMEvent()
#include "mozilla/dom/ScreenBinding.h"
#include "nsContentUtils.h"
#include "nsScreen.h"
#include "nsIDocument.h"
#include "nsIDocShell.h"
#include "nsIDocument.h"
#include "nsPresContext.h"
#include "nsCOMPtr.h"
#include "nsIDocShellTreeItem.h"
#include "nsLayoutUtils.h"
#include "nsJSUtils.h"
#include "nsDeviceContext.h"

using namespace mozilla;
using namespace mozilla::dom;

/* static */ already_AddRefed<nsScreen>
nsScreen::Create(nsPIDOMWindowInner* aWindow)
{
  MOZ_ASSERT(aWindow);
  MOZ_ASSERT(aWindow->IsInnerWindow());

  if (!aWindow->GetDocShell()) {
    return nullptr;
  }

  nsCOMPtr<nsIScriptGlobalObject> sgo = do_QueryInterface(aWindow);
  NS_ENSURE_TRUE(sgo, nullptr);

  RefPtr<nsScreen> screen = new nsScreen(aWindow);
  return screen.forget();
}

nsScreen::nsScreen(nsPIDOMWindowInner* aWindow)
  : DOMEventTargetHelper(aWindow)
  , mScreenOrientation(new ScreenOrientation(aWindow, this))
{
}

nsScreen::~nsScreen()
{
}


// QueryInterface implementation for nsScreen
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(nsScreen)
  NS_INTERFACE_MAP_ENTRY(nsIDOMScreen)
NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)

NS_IMPL_ADDREF_INHERITED(nsScreen, DOMEventTargetHelper)
NS_IMPL_RELEASE_INHERITED(nsScreen, DOMEventTargetHelper)

NS_IMPL_CYCLE_COLLECTION_INHERITED(nsScreen,
                                   DOMEventTargetHelper,
                                   mScreenOrientation)

int32_t
nsScreen::GetPixelDepth(ErrorResult& aRv)
{
  // Return 24 to prevent fingerprinting.
  if (ShouldResistFingerprinting()) {
    return 24;
  }

  nsDeviceContext* context = GetDeviceContext();

  if (!context) {
    aRv.Throw(NS_ERROR_FAILURE);
    return -1;
  }

  uint32_t depth;
  context->GetDepth(depth);
  return depth;
}

#define FORWARD_LONG_GETTER(_name)                                              \
  NS_IMETHODIMP                                                                 \
  nsScreen::Get ## _name(int32_t* aOut)                                         \
  {                                                                             \
    ErrorResult rv;                                                             \
    *aOut = Get ## _name(rv);                                                   \
    return rv.StealNSResult();                                                  \
  }

FORWARD_LONG_GETTER(AvailWidth)
FORWARD_LONG_GETTER(AvailHeight)
FORWARD_LONG_GETTER(Width)
FORWARD_LONG_GETTER(Height)

FORWARD_LONG_GETTER(Top)
FORWARD_LONG_GETTER(Left)
FORWARD_LONG_GETTER(AvailTop)
FORWARD_LONG_GETTER(AvailLeft)

FORWARD_LONG_GETTER(PixelDepth)
FORWARD_LONG_GETTER(ColorDepth)

nsPIDOMWindowOuter*
nsScreen::GetOuter() const
{
  if (nsPIDOMWindowInner* inner = GetOwner()) {
    return inner->GetOuterWindow();
  }

  return nullptr;
}

nsDeviceContext*
nsScreen::GetDeviceContext()
{
  return nsLayoutUtils::GetDeviceContextForScreenInfo(GetOuter());
}

nsresult
nsScreen::GetRect(nsRect& aRect)
{
  // Return window inner rect to prevent fingerprinting.
  if (ShouldResistFingerprinting()) {
    return GetWindowInnerRect(aRect);
  }

  nsDeviceContext *context = GetDeviceContext();

  if (!context) {
    return NS_ERROR_FAILURE;
  }

  context->GetRect(aRect);
  LayoutDevicePoint screenTopLeftDev =
    LayoutDevicePixel::FromAppUnits(aRect.TopLeft(),
                                    context->AppUnitsPerDevPixel());
  DesktopPoint screenTopLeftDesk =
    screenTopLeftDev / context->GetDesktopToDeviceScale();

  aRect.x = NSToIntRound(screenTopLeftDesk.x);
  aRect.y = NSToIntRound(screenTopLeftDesk.y);

  aRect.height = nsPresContext::AppUnitsToIntCSSPixels(aRect.height);
  aRect.width = nsPresContext::AppUnitsToIntCSSPixels(aRect.width);

  return NS_OK;
}

nsresult
nsScreen::GetAvailRect(nsRect& aRect)
{
  // Return window inner rect to prevent fingerprinting.
  if (ShouldResistFingerprinting()) {
    return GetWindowInnerRect(aRect);
  }

  nsDeviceContext *context = GetDeviceContext();

  if (!context) {
    return NS_ERROR_FAILURE;
  }

  nsRect r;
  context->GetRect(r);
  LayoutDevicePoint screenTopLeftDev =
    LayoutDevicePixel::FromAppUnits(r.TopLeft(),
                                    context->AppUnitsPerDevPixel());
  DesktopPoint screenTopLeftDesk =
    screenTopLeftDev / context->GetDesktopToDeviceScale();

  context->GetClientRect(aRect);

  aRect.x = NSToIntRound(screenTopLeftDesk.x) +
            nsPresContext::AppUnitsToIntCSSPixels(aRect.x - r.x);
  aRect.y = NSToIntRound(screenTopLeftDesk.y) +
            nsPresContext::AppUnitsToIntCSSPixels(aRect.y - r.y);

  aRect.height = nsPresContext::AppUnitsToIntCSSPixels(aRect.height);
  aRect.width = nsPresContext::AppUnitsToIntCSSPixels(aRect.width);

  return NS_OK;
}

mozilla::dom::ScreenOrientation*
nsScreen::Orientation() const
{
  return mScreenOrientation;
}

void
nsScreen::GetMozOrientation(nsString& aOrientation) const
{
  switch (mScreenOrientation->DeviceType()) {
  case OrientationType::Portrait_primary:
    aOrientation.AssignLiteral("portrait-primary");
    break;
  case OrientationType::Portrait_secondary:
    aOrientation.AssignLiteral("portrait-secondary");
    break;
  case OrientationType::Landscape_primary:
    aOrientation.AssignLiteral("landscape-primary");
    break;
  case OrientationType::Landscape_secondary:
    aOrientation.AssignLiteral("landscape-secondary");
    break;
  default:
    MOZ_CRASH("Unacceptable screen orientation type.");
  }
}

NS_IMETHODIMP
nsScreen::GetSlowMozOrientation(nsAString& aOrientation)
{
  nsString orientation;
  GetMozOrientation(orientation);
  aOrientation = orientation;
  return NS_OK;
}

static void
UpdateDocShellOrientationLock(nsPIDOMWindowInner* aWindow,
                              ScreenOrientationInternal aOrientation)
{
  if (!aWindow) {
    return;
  }

  nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell();
  if (!docShell) {
    return;
  }

  nsCOMPtr<nsIDocShellTreeItem> root;
  docShell->GetSameTypeRootTreeItem(getter_AddRefs(root));
  nsCOMPtr<nsIDocShell> rootShell(do_QueryInterface(root));
  if (!rootShell) {
    return;
  }

  rootShell->SetOrientationLock(aOrientation);
}

bool
nsScreen::MozLockOrientation(const nsAString& aOrientation, ErrorResult& aRv)
{
  nsString orientation(aOrientation);
  Sequence<nsString> orientations;
  if (!orientations.AppendElement(orientation, fallible)) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return false;
  }
  return MozLockOrientation(orientations, aRv);
}

bool
nsScreen::MozLockOrientation(const Sequence<nsString>& aOrientations,
                             ErrorResult& aRv)
{
  if (ShouldResistFingerprinting()) {
    return false;
  }
  ScreenOrientationInternal orientation = eScreenOrientation_None;

  for (uint32_t i = 0; i < aOrientations.Length(); ++i) {
    const nsString& item = aOrientations[i];

    if (item.EqualsLiteral("portrait")) {
      orientation |= eScreenOrientation_PortraitPrimary |
                     eScreenOrientation_PortraitSecondary;
    } else if (item.EqualsLiteral("portrait-primary")) {
      orientation |= eScreenOrientation_PortraitPrimary;
    } else if (item.EqualsLiteral("portrait-secondary")) {
      orientation |= eScreenOrientation_PortraitSecondary;
    } else if (item.EqualsLiteral("landscape")) {
      orientation |= eScreenOrientation_LandscapePrimary |
                     eScreenOrientation_LandscapeSecondary;
    } else if (item.EqualsLiteral("landscape-primary")) {
      orientation |= eScreenOrientation_LandscapePrimary;
    } else if (item.EqualsLiteral("landscape-secondary")) {
      orientation |= eScreenOrientation_LandscapeSecondary;
    } else if (item.EqualsLiteral("default")) {
      orientation |= eScreenOrientation_Default;
    } else {
      // If we don't recognize the token, we should just return 'false'
      // without throwing.
      return false;
    }
  }

  switch (mScreenOrientation->GetLockOrientationPermission(false)) {
    case ScreenOrientation::LOCK_DENIED:
      return false;
    case ScreenOrientation::LOCK_ALLOWED:
      UpdateDocShellOrientationLock(GetOwner(), orientation);
      return mScreenOrientation->LockDeviceOrientation(orientation, false, aRv);
    case ScreenOrientation::FULLSCREEN_LOCK_ALLOWED:
      UpdateDocShellOrientationLock(GetOwner(), orientation);
      return mScreenOrientation->LockDeviceOrientation(orientation, true, aRv);
  }

  // This is only for compilers that don't understand that the previous switch
  // will always return.
  MOZ_CRASH("unexpected lock orientation permission value");
}

void
nsScreen::MozUnlockOrientation()
{
  if (ShouldResistFingerprinting()) {
    return;
  }
  UpdateDocShellOrientationLock(GetOwner(), eScreenOrientation_None);
  mScreenOrientation->UnlockDeviceOrientation();
}

bool
nsScreen::IsDeviceSizePageSize()
{
  if (nsPIDOMWindowInner* owner = GetOwner()) {
    nsIDocShell* docShell = owner->GetDocShell();
    if (docShell) {
      return docShell->GetDeviceSizeIsPageSize();
    }
  }
  return false;
}

/* virtual */
JSObject*
nsScreen::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  return ScreenBinding::Wrap(aCx, this, aGivenProto);
}

nsresult
nsScreen::GetWindowInnerRect(nsRect& aRect)
{
  aRect.x = 0;
  aRect.y = 0;
  nsCOMPtr<nsPIDOMWindowInner> win = GetOwner();
  if (!win) {
    return NS_ERROR_FAILURE;
  }
  nsresult rv = win->GetInnerWidth(&aRect.width);
  NS_ENSURE_SUCCESS(rv, rv);
  return win->GetInnerHeight(&aRect.height);
}

bool nsScreen::ShouldResistFingerprinting() const
{
  bool resist = false;
  nsCOMPtr<nsPIDOMWindowInner> owner = GetOwner();
  if (owner) {
    resist = nsContentUtils::ShouldResistFingerprinting(owner->GetDocShell());
  }
  return resist;
}