dom/events/KeyboardEvent.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/KeyboardEvent.h"
#include "mozilla/TextEvents.h"
#include "nsContentUtils.h"
#include "prtime.h"

namespace mozilla {
namespace dom {

KeyboardEvent::KeyboardEvent(EventTarget* aOwner, nsPresContext* aPresContext,
                             WidgetKeyboardEvent* aEvent)
    : UIEvent(aOwner, aPresContext,
              aEvent ? aEvent
                     : new WidgetKeyboardEvent(false, eVoidEvent, nullptr)),
      mInitializedByCtor(false),
      mInitializedWhichValue(0) {
  if (aEvent) {
    mEventIsInternal = false;
  } else {
    mEventIsInternal = true;
    mEvent->mTime = PR_Now();
    mEvent->AsKeyboardEvent()->mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
  }
}

bool KeyboardEvent::AltKey(CallerType aCallerType) {
  bool altState = mEvent->AsKeyboardEvent()->IsAlt();

  if (!ShouldResistFingerprinting(aCallerType)) {
    return altState;
  }

  // We need to give a spoofed state for Alt key since it could be used as a
  // modifier key in certain keyboard layout. For example, the '@' key for
  // German keyboard for MAC is Alt+L.
  return GetSpoofedModifierStates(Modifier::MODIFIER_ALT, altState);
}

bool KeyboardEvent::CtrlKey(CallerType aCallerType) {
  // We don't spoof this key when privacy.resistFingerprinting
  // is enabled, because it is often used for command key
  // combinations in web apps.
  return mEvent->AsKeyboardEvent()->IsControl();
}

bool KeyboardEvent::ShiftKey(CallerType aCallerType) {
  bool shiftState = mEvent->AsKeyboardEvent()->IsShift();

  if (!ShouldResistFingerprinting(aCallerType)) {
    return shiftState;
  }

  return GetSpoofedModifierStates(Modifier::MODIFIER_SHIFT, shiftState);
}

bool KeyboardEvent::MetaKey() {
  // We don't spoof this key when privacy.resistFingerprinting
  // is enabled, because it is often used for command key
  // combinations in web apps.
  return mEvent->AsKeyboardEvent()->IsMeta();
}

bool KeyboardEvent::Repeat() { return mEvent->AsKeyboardEvent()->mIsRepeat; }

bool KeyboardEvent::IsComposing() {
  return mEvent->AsKeyboardEvent()->mIsComposing;
}

void KeyboardEvent::GetKey(nsAString& aKeyName) const {
  mEvent->AsKeyboardEvent()->GetDOMKeyName(aKeyName);
}

void KeyboardEvent::GetCode(nsAString& aCodeName, CallerType aCallerType) {
  if (!ShouldResistFingerprinting(aCallerType)) {
    mEvent->AsKeyboardEvent()->GetDOMCodeName(aCodeName);
    return;
  }

  // When fingerprinting resistance is enabled, we will give a spoofed code
  // according to the content-language of the document.
  nsCOMPtr<nsIDocument> doc = GetDocument();

  nsRFPService::GetSpoofedCode(doc, mEvent->AsKeyboardEvent(), aCodeName);
}

void KeyboardEvent::GetInitDict(KeyboardEventInit& aParam) {
  GetKey(aParam.mKey);
  GetCode(aParam.mCode);
  aParam.mLocation = Location();
  aParam.mRepeat = Repeat();
  aParam.mIsComposing = IsComposing();

  // legacy attributes
  aParam.mKeyCode = KeyCode();
  aParam.mCharCode = CharCode();
  aParam.mWhich = Which();

  // modifiers from EventModifierInit
  aParam.mCtrlKey = CtrlKey();
  aParam.mShiftKey = ShiftKey();
  aParam.mAltKey = AltKey();
  aParam.mMetaKey = MetaKey();

  WidgetKeyboardEvent* internalEvent = mEvent->AsKeyboardEvent();
  aParam.mModifierAltGraph = internalEvent->IsAltGraph();
  aParam.mModifierCapsLock = internalEvent->IsCapsLocked();
  aParam.mModifierFn = internalEvent->IsFn();
  aParam.mModifierFnLock = internalEvent->IsFnLocked();
  aParam.mModifierNumLock = internalEvent->IsNumLocked();
  aParam.mModifierOS = internalEvent->IsOS();
  aParam.mModifierScrollLock = internalEvent->IsScrollLocked();
  aParam.mModifierSymbol = internalEvent->IsSymbol();
  aParam.mModifierSymbolLock = internalEvent->IsSymbolLocked();

  // EventInit
  aParam.mBubbles = internalEvent->mFlags.mBubbles;
  aParam.mCancelable = internalEvent->mFlags.mCancelable;
}

uint32_t KeyboardEvent::CharCode() {
  // If this event is initialized with ctor, we shouldn't check event type.
  if (mInitializedByCtor) {
    return mEvent->AsKeyboardEvent()->mCharCode;
  }

  switch (mEvent->mMessage) {
    case eKeyDown:
    case eKeyDownOnPlugin:
    case eKeyUp:
    case eKeyUpOnPlugin:
      return 0;
    case eKeyPress:
    case eAccessKeyNotFound:
      return mEvent->AsKeyboardEvent()->mCharCode;
    default:
      break;
  }
  return 0;
}

uint32_t KeyboardEvent::KeyCode(CallerType aCallerType) {
  // If this event is initialized with ctor, we shouldn't check event type.
  if (mInitializedByCtor) {
    return mEvent->AsKeyboardEvent()->mKeyCode;
  }

  if (!mEvent->HasKeyEventMessage()) {
    return 0;
  }

  if (!ShouldResistFingerprinting(aCallerType)) {
    return mEvent->AsKeyboardEvent()->mKeyCode;
  }

  // The keyCode should be zero if the char code is given.
  if (CharCode()) {
    return 0;
  }

  // When fingerprinting resistance is enabled, we will give a spoofed keyCode
  // according to the content-language of the document.
  nsCOMPtr<nsIDocument> doc = GetDocument();
  uint32_t spoofedKeyCode;

  if (nsRFPService::GetSpoofedKeyCode(doc, mEvent->AsKeyboardEvent(),
                                      spoofedKeyCode)) {
    return spoofedKeyCode;
  }

  return 0;
}

uint32_t KeyboardEvent::Which(CallerType aCallerType) {
  // If this event is initialized with ctor, which can have independent value.
  if (mInitializedByCtor) {
    return mInitializedWhichValue;
  }

  switch (mEvent->mMessage) {
    case eKeyDown:
    case eKeyDownOnPlugin:
    case eKeyUp:
    case eKeyUpOnPlugin:
      return KeyCode(aCallerType);
    case eKeyPress:
      // Special case for 4xp bug 62878.  Try to make value of which
      // more closely mirror the values that 4.x gave for RETURN and BACKSPACE
      {
        uint32_t keyCode = mEvent->AsKeyboardEvent()->mKeyCode;
        if (keyCode == NS_VK_RETURN || keyCode == NS_VK_BACK) {
          return keyCode;
        }
        return CharCode();
      }
    default:
      break;
  }

  return 0;
}

uint32_t KeyboardEvent::Location() {
  return mEvent->AsKeyboardEvent()->mLocation;
}

// static
already_AddRefed<KeyboardEvent> KeyboardEvent::Constructor(
    const GlobalObject& aGlobal, const nsAString& aType,
    const KeyboardEventInit& aParam, ErrorResult& aRv) {
  nsCOMPtr<EventTarget> target = do_QueryInterface(aGlobal.GetAsSupports());
  RefPtr<KeyboardEvent> newEvent = new KeyboardEvent(target, nullptr, nullptr);
  newEvent->InitWithKeyboardEventInit(target, aType, aParam, aRv);

  return newEvent.forget();
}

void KeyboardEvent::InitWithKeyboardEventInit(EventTarget* aOwner,
                                              const nsAString& aType,
                                              const KeyboardEventInit& aParam,
                                              ErrorResult& aRv) {
  bool trusted = Init(aOwner);
  InitKeyEvent(aType, aParam.mBubbles, aParam.mCancelable, aParam.mView, false,
               false, false, false, aParam.mKeyCode, aParam.mCharCode);
  InitModifiers(aParam);
  SetTrusted(trusted);
  mDetail = aParam.mDetail;
  mInitializedByCtor = true;
  mInitializedWhichValue = aParam.mWhich;

  WidgetKeyboardEvent* internalEvent = mEvent->AsKeyboardEvent();
  internalEvent->mLocation = aParam.mLocation;
  internalEvent->mIsRepeat = aParam.mRepeat;
  internalEvent->mIsComposing = aParam.mIsComposing;
  internalEvent->mKeyNameIndex =
      WidgetKeyboardEvent::GetKeyNameIndex(aParam.mKey);
  if (internalEvent->mKeyNameIndex == KEY_NAME_INDEX_USE_STRING) {
    internalEvent->mKeyValue = aParam.mKey;
  }
  internalEvent->mCodeNameIndex =
      WidgetKeyboardEvent::GetCodeNameIndex(aParam.mCode);
  if (internalEvent->mCodeNameIndex == CODE_NAME_INDEX_USE_STRING) {
    internalEvent->mCodeValue = aParam.mCode;
  }
}

void KeyboardEvent::InitKeyEvent(const nsAString& aType, bool aCanBubble,
                                 bool aCancelable, nsGlobalWindowInner* aView,
                                 bool aCtrlKey, bool aAltKey, bool aShiftKey,
                                 bool aMetaKey, uint32_t aKeyCode,
                                 uint32_t aCharCode) {
  NS_ENSURE_TRUE_VOID(!mEvent->mFlags.mIsBeingDispatched);

  UIEvent::InitUIEvent(aType, aCanBubble, aCancelable, aView, 0);

  WidgetKeyboardEvent* keyEvent = mEvent->AsKeyboardEvent();
  keyEvent->InitBasicModifiers(aCtrlKey, aAltKey, aShiftKey, aMetaKey);
  keyEvent->mKeyCode = aKeyCode;
  keyEvent->mCharCode = aCharCode;
}

void KeyboardEvent::InitKeyboardEvent(const nsAString& aType, bool aCanBubble,
                                      bool aCancelable,
                                      nsGlobalWindowInner* aView,
                                      const nsAString& aKey, uint32_t aLocation,
                                      bool aCtrlKey, bool aAltKey,
                                      bool aShiftKey, bool aMetaKey,
                                      ErrorResult& aRv) {
  NS_ENSURE_TRUE_VOID(!mEvent->mFlags.mIsBeingDispatched);

  UIEvent::InitUIEvent(aType, aCanBubble, aCancelable, aView, 0);

  WidgetKeyboardEvent* keyEvent = mEvent->AsKeyboardEvent();
  keyEvent->InitBasicModifiers(aCtrlKey, aAltKey, aShiftKey, aMetaKey);
  keyEvent->mLocation = aLocation;
  keyEvent->mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
  keyEvent->mKeyValue = aKey;
}

already_AddRefed<nsIDocument> KeyboardEvent::GetDocument() {
  nsCOMPtr<nsIDocument> doc;
  nsCOMPtr<EventTarget> eventTarget = InternalDOMEvent()->GetTarget();

  if (eventTarget) {
    nsCOMPtr<nsPIDOMWindowInner> win =
        do_QueryInterface(eventTarget->GetOwnerGlobal());

    if (win) {
      doc = win->GetExtantDoc();
    }
  }

  return doc.forget();
}

bool KeyboardEvent::ShouldResistFingerprinting(CallerType aCallerType) {
  // There are five situations we don't need to spoof this keyboard event.
  //   1. This event is generated by scripts.
  //   2. This event is from Numpad.
  //   3. This event is in the system group.
  //   4. The caller type is system.
  //   5. The pref privcy.resistFingerprinting' is false, we fast return here
  //      since we don't need to do any QI of following codes.
  if (mInitializedByCtor || aCallerType == CallerType::System ||
      mEvent->mFlags.mInSystemGroup ||
      !nsContentUtils::ShouldResistFingerprinting() ||
      mEvent->AsKeyboardEvent()->mLocation ==
          KeyboardEventBinding::DOM_KEY_LOCATION_NUMPAD) {
    return false;
  }

  nsCOMPtr<nsIDocument> doc = GetDocument();

  return doc && !nsContentUtils::IsChromeDoc(doc);
}

bool KeyboardEvent::GetSpoofedModifierStates(const Modifiers aModifierKey,
                                             const bool aRawModifierState) {
  bool spoofedState;
  nsCOMPtr<nsIDocument> doc = GetDocument();

  if (nsRFPService::GetSpoofedModifierStates(doc, mEvent->AsKeyboardEvent(),
                                             aModifierKey, spoofedState)) {
    return spoofedState;
  }

  return aRawModifierState;
}

}  // namespace dom
}  // namespace mozilla

using namespace mozilla;
using namespace mozilla::dom;

already_AddRefed<KeyboardEvent> NS_NewDOMKeyboardEvent(
    EventTarget* aOwner, nsPresContext* aPresContext,
    WidgetKeyboardEvent* aEvent) {
  RefPtr<KeyboardEvent> it = new KeyboardEvent(aOwner, aPresContext, aEvent);
  return it.forget();
}