Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1120 insertions, 0 deletions

diff --git a/widget/windows/KeyboardLayout.h b/widget/windows/KeyboardLayout.h
new file mode 100644
index 0000000000..c7c3bcc56d
--- /dev/null
+++ b/widget/windows/KeyboardLayout.h
@@ -0,0 +1,1120 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef KeyboardLayout_h__
+#define KeyboardLayout_h__
+
+#include "mozilla/RefPtr.h"
+#include "nscore.h"
+#include "nsString.h"
+#include "nsWindow.h"
+#include "nsWindowDefs.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/widget/WinMessages.h"
+#include "mozilla/widget/WinModifierKeyState.h"
+#include <windows.h>
+
+#define NS_NUM_OF_KEYS 70
+
+#define VK_OEM_1 0xBA     // ';:' for US
+#define VK_OEM_PLUS 0xBB  // '+' any country
+#define VK_OEM_COMMA 0xBC
+#define VK_OEM_MINUS 0xBD  // '-' any country
+#define VK_OEM_PERIOD 0xBE
+#define VK_OEM_2 0xBF
+#define VK_OEM_3 0xC0
+// '/?' for Brazilian (ABNT)
+#define VK_ABNT_C1 0xC1
+// Separator in Numpad for Brazilian (ABNT) or JIS keyboard for Mac.
+#define VK_ABNT_C2 0xC2
+#define VK_OEM_4 0xDB
+#define VK_OEM_5 0xDC
+#define VK_OEM_6 0xDD
+#define VK_OEM_7 0xDE
+#define VK_OEM_8 0xDF
+#define VK_OEM_102 0xE2
+#define VK_OEM_CLEAR 0xFE
+
+class nsIUserIdleServiceInternal;
+
+namespace mozilla {
+namespace widget {
+
+enum ScanCode : uint16_t {
+  eCapsLock = 0x003A,
+  eNumLock = 0xE045,
+  eShiftLeft = 0x002A,
+  eShiftRight = 0x0036,
+  eControlLeft = 0x001D,
+  eControlRight = 0xE01D,
+  eAltLeft = 0x0038,
+  eAltRight = 0xE038,
+};
+
+// 0: nsIWidget's native modifier flag
+// 1: Virtual keycode which does not distinguish whether left or right location.
+// 2: Virtual keycode which distinguishes whether left or right location.
+// 3: Scan code.
+static const uint32_t sModifierKeyMap[][4] = {
+    {nsIWidget::CAPS_LOCK, VK_CAPITAL, 0, ScanCode::eCapsLock},
+    {nsIWidget::NUM_LOCK, VK_NUMLOCK, 0, ScanCode::eNumLock},
+    {nsIWidget::SHIFT_L, VK_SHIFT, VK_LSHIFT, ScanCode::eShiftLeft},
+    {nsIWidget::SHIFT_R, VK_SHIFT, VK_RSHIFT, ScanCode::eShiftRight},
+    {nsIWidget::CTRL_L, VK_CONTROL, VK_LCONTROL, ScanCode::eControlLeft},
+    {nsIWidget::CTRL_R, VK_CONTROL, VK_RCONTROL, ScanCode::eControlRight},
+    {nsIWidget::ALT_L, VK_MENU, VK_LMENU, ScanCode::eAltLeft},
+    {nsIWidget::ALT_R, VK_MENU, VK_RMENU, ScanCode::eAltRight}};
+
+class KeyboardLayout;
+
+class MOZ_STACK_CLASS UniCharsAndModifiers final {
+ public:
+  UniCharsAndModifiers() {}
+  UniCharsAndModifiers operator+(const UniCharsAndModifiers& aOther) const;
+  UniCharsAndModifiers& operator+=(const UniCharsAndModifiers& aOther);
+
+  /**
+   * Append a pair of unicode character and the final modifier.
+   */
+  void Append(char16_t aUniChar, Modifiers aModifiers);
+  void Clear() {
+    mChars.Truncate();
+    mModifiers.Clear();
+  }
+  bool IsEmpty() const {
+    MOZ_ASSERT(mChars.Length() == mModifiers.Length());
+    return mChars.IsEmpty();
+  }
+
+  char16_t CharAt(size_t aIndex) const {
+    MOZ_ASSERT(aIndex < Length());
+    return mChars[aIndex];
+  }
+  Modifiers ModifiersAt(size_t aIndex) const {
+    MOZ_ASSERT(aIndex < Length());
+    return mModifiers[aIndex];
+  }
+  size_t Length() const {
+    MOZ_ASSERT(mChars.Length() == mModifiers.Length());
+    return mChars.Length();
+  }
+
+  bool IsProducingCharsWithAltGr() const {
+    return !IsEmpty() && (ModifiersAt(0) & MODIFIER_ALTGRAPH) != 0;
+  }
+
+  void FillModifiers(Modifiers aModifiers);
+  /**
+   * OverwriteModifiersIfBeginsWith() assigns mModifiers with aOther between
+   * [0] and [aOther.mLength - 1] only when mChars begins with aOther.mChars.
+   */
+  void OverwriteModifiersIfBeginsWith(const UniCharsAndModifiers& aOther);
+
+  bool UniCharsEqual(const UniCharsAndModifiers& aOther) const;
+  bool UniCharsCaseInsensitiveEqual(const UniCharsAndModifiers& aOther) const;
+  bool BeginsWith(const UniCharsAndModifiers& aOther) const;
+
+  const nsString& ToString() const { return mChars; }
+
+ private:
+  nsAutoString mChars;
+  // 5 is enough number for normal keyboard layout handling.  On Windows,
+  // a dead key sequence may cause inputting up to 5 characters per key press.
+  CopyableAutoTArray<Modifiers, 5> mModifiers;
+};
+
+struct DeadKeyEntry {
+  char16_t BaseChar;
+  char16_t CompositeChar;
+};
+
+class DeadKeyTable {
+  friend class KeyboardLayout;
+
+  uint16_t mEntries;
+  // KeyboardLayout::AddDeadKeyTable() will allocate as many entries as
+  // required.  It is the only way to create new DeadKeyTable instances.
+  DeadKeyEntry mTable[1];
+
+  void Init(const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) {
+    mEntries = aEntries;
+    memcpy(mTable, aDeadKeyArray, aEntries * sizeof(DeadKeyEntry));
+  }
+
+  static uint32_t SizeInBytes(uint32_t aEntries) {
+    return offsetof(DeadKeyTable, mTable) + aEntries * sizeof(DeadKeyEntry);
+  }
+
+ public:
+  uint32_t Entries() const { return mEntries; }
+
+  bool IsEqual(const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) const {
+    return (mEntries == aEntries &&
+            !memcmp(mTable, aDeadKeyArray, aEntries * sizeof(DeadKeyEntry)));
+  }
+
+  char16_t GetCompositeChar(char16_t aBaseChar) const;
+};
+
+class VirtualKey {
+ public:
+  enum ShiftStateIndex : uint8_t {
+    //  0 - Normal
+    eNormal = 0,
+    //  1 - Shift
+    eShift,
+    //  2 - Control
+    eControl,
+    //  3 - Control + Shift
+    eControlShift,
+    //  4 - Alt
+    eAlt,
+    //  5 - Alt + Shift
+    eAltShift,
+    //  6 - Alt + Control (AltGr)
+    eAltGr,
+    //  7 - Alt + Control + Shift (AltGr + Shift)
+    eAltGrShift,
+    //  8 - CapsLock
+    eWithCapsLock,
+    //  9 - CapsLock + Shift
+    eShiftWithCapsLock,
+    // 10 - CapsLock + Control
+    eControlWithCapsLock,
+    // 11 - CapsLock + Control + Shift
+    eControlShiftWithCapsLock,
+    // 12 - CapsLock + Alt
+    eAltWithCapsLock,
+    // 13 - CapsLock + Alt + Shift
+    eAltShiftWithCapsLock,
+    // 14 - CapsLock + Alt + Control (CapsLock + AltGr)
+    eAltGrWithCapsLock,
+    // 15 - CapsLock + Alt + Control + Shift (CapsLock + AltGr + Shift)
+    eAltGrShiftWithCapsLock,
+  };
+
+  enum ShiftStateFlag {
+    STATE_SHIFT = 0x01,
+    STATE_CONTROL = 0x02,
+    STATE_ALT = 0x04,
+    STATE_CAPSLOCK = 0x08,
+    // ShiftState needs to have AltGr state separately since this is necessary
+    // for lossless conversion with Modifiers.
+    STATE_ALTGRAPH = 0x80,
+    // Useful to remove or check Ctrl and Alt flags.
+    STATE_CONTROL_ALT = STATE_CONTROL | STATE_ALT,
+  };
+
+  typedef uint8_t ShiftState;
+
+  static ShiftState ModifiersToShiftState(Modifiers aModifiers);
+  static ShiftState ModifierKeyStateToShiftState(
+      const ModifierKeyState& aModKeyState) {
+    return ModifiersToShiftState(aModKeyState.GetModifiers());
+  }
+  static Modifiers ShiftStateToModifiers(ShiftState aShiftState);
+  static bool IsAltGrIndex(uint8_t aIndex) {
+    return (aIndex & STATE_CONTROL_ALT) == STATE_CONTROL_ALT;
+  }
+
+ private:
+  union KeyShiftState {
+    struct {
+      char16_t Chars[4];
+    } Normal;
+    struct {
+      const DeadKeyTable* Table;
+      char16_t DeadChar;
+    } DeadKey;
+  };
+
+  KeyShiftState mShiftStates[16];
+  uint16_t mIsDeadKey;
+
+  static uint8_t ToShiftStateIndex(ShiftState aShiftState) {
+    if (!(aShiftState & STATE_ALTGRAPH)) {
+      MOZ_ASSERT(aShiftState <= eAltGrShiftWithCapsLock);
+      return static_cast<uint8_t>(aShiftState);
+    }
+    uint8_t index = aShiftState & ~STATE_ALTGRAPH;
+    index |= (STATE_ALT | STATE_CONTROL);
+    MOZ_ASSERT(index <= eAltGrShiftWithCapsLock);
+    return index;
+  }
+
+  void SetDeadKey(ShiftState aShiftState, bool aIsDeadKey) {
+    if (aIsDeadKey) {
+      mIsDeadKey |= 1 << ToShiftStateIndex(aShiftState);
+    } else {
+      mIsDeadKey &= ~(1 << ToShiftStateIndex(aShiftState));
+    }
+  }
+
+ public:
+  static void FillKbdState(PBYTE aKbdState, const ShiftState aShiftState);
+
+  bool IsDeadKey(ShiftState aShiftState) const {
+    return (mIsDeadKey & (1 << ToShiftStateIndex(aShiftState))) != 0;
+  }
+
+  /**
+   * IsChangedByAltGr() is useful to check if a key with AltGr produces
+   * different character(s) from the key without AltGr.
+   * Note that this is designed for checking if a keyboard layout has AltGr
+   * key.  So, this result may not exactly correct for the key since it's
+   * okay to fails in some edge cases when we check all keys which produce
+   * character(s) in a layout.
+   */
+  bool IsChangedByAltGr(ShiftState aShiftState) const {
+    MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+    MOZ_ASSERT(IsAltGrIndex(aShiftState));
+    MOZ_ASSERT(IsDeadKey(aShiftState) ||
+               mShiftStates[aShiftState].Normal.Chars[0]);
+    const ShiftState kShiftStateWithoutAltGr =
+        aShiftState - ShiftStateIndex::eAltGr;
+    if (IsDeadKey(aShiftState) != IsDeadKey(kShiftStateWithoutAltGr)) {
+      return false;
+    }
+    if (IsDeadKey(aShiftState)) {
+      return mShiftStates[aShiftState].DeadKey.DeadChar !=
+             mShiftStates[kShiftStateWithoutAltGr].DeadKey.DeadChar;
+    }
+    for (size_t i = 0; i < 4; i++) {
+      if (mShiftStates[aShiftState].Normal.Chars[i] !=
+          mShiftStates[kShiftStateWithoutAltGr].Normal.Chars[i]) {
+        return true;
+      }
+      if (!mShiftStates[aShiftState].Normal.Chars[i] &&
+          !mShiftStates[kShiftStateWithoutAltGr].Normal.Chars[i]) {
+        return false;
+      }
+    }
+    return false;
+  }
+
+  void AttachDeadKeyTable(ShiftState aShiftState,
+                          const DeadKeyTable* aDeadKeyTable) {
+    MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+    mShiftStates[aShiftState].DeadKey.Table = aDeadKeyTable;
+  }
+
+  void SetNormalChars(ShiftState aShiftState, const char16_t* aChars,
+                      uint32_t aNumOfChars);
+  void SetDeadChar(ShiftState aShiftState, char16_t aDeadChar);
+  const DeadKeyTable* MatchingDeadKeyTable(const DeadKeyEntry* aDeadKeyArray,
+                                           uint32_t aEntries) const;
+  inline char16_t GetCompositeChar(ShiftState aShiftState,
+                                   char16_t aBaseChar) const {
+    return mShiftStates[ToShiftStateIndex(aShiftState)]
+        .DeadKey.Table->GetCompositeChar(aBaseChar);
+  }
+
+  char16_t GetCompositeChar(const ModifierKeyState& aModKeyState,
+                            char16_t aBaseChar) const {
+    return GetCompositeChar(ModifierKeyStateToShiftState(aModKeyState),
+                            aBaseChar);
+  }
+
+  /**
+   * GetNativeUniChars() returns character(s) which is produced by the
+   * key with given modifiers.  This does NOT return proper MODIFIER_ALTGRAPH
+   * state because this is raw accessor of the database of this key.
+   */
+  UniCharsAndModifiers GetNativeUniChars(ShiftState aShiftState) const;
+  UniCharsAndModifiers GetNativeUniChars(
+      const ModifierKeyState& aModKeyState) const {
+    return GetNativeUniChars(ModifierKeyStateToShiftState(aModKeyState));
+  }
+
+  /**
+   * GetUniChars() returns characters and modifiers which are not consumed
+   * to input the character.
+   * For example, if you specify Ctrl key but the key produces no character
+   * with Ctrl, this returns character(s) which is produced by the key
+   * without Ctrl.  So, the result is useful to decide KeyboardEvent.key
+   * value.
+   * Another example is, if you specify Ctrl key and the key produces
+   * different character(s) from the case without Ctrl key, this returns
+   * the character(s) *without* MODIFIER_CONTROL.  This modifier information
+   * is useful for eKeyPress since TextEditor does not treat eKeyPress events
+   * whose modifier includes MODIFIER_ALT and/or MODIFIER_CONTROL.
+   *
+   * @param aShiftState         Modifiers which you want to retrieve
+   *                            KeyboardEvent.key value for the key with.
+   *                            If AltGr key is pressed, this should include
+   *                            STATE_ALTGRAPH and should NOT include
+   *                            STATE_ALT nor STATE_CONTROL.
+   *                            If both Alt and Ctrl are pressed to emulate
+   *                            AltGr, this should include both STATE_ALT and
+   *                            STATE_CONTROL but should NOT include
+   *                            MODIFIER_ALTGRAPH.
+   *                            Then, this returns proper modifiers when
+   *                            this key produces no character with AltGr.
+   */
+  UniCharsAndModifiers GetUniChars(ShiftState aShiftState) const;
+  UniCharsAndModifiers GetUniChars(const ModifierKeyState& aModKeyState) const {
+    return GetUniChars(ModifierKeyStateToShiftState(aModKeyState));
+  }
+};
+
+class MOZ_STACK_CLASS NativeKey final {
+  friend class KeyboardLayout;
+
+ public:
+  struct FakeCharMsg {
+    UINT mCharCode;
+    UINT mScanCode;
+    bool mIsSysKey;
+    bool mIsDeadKey;
+    bool mConsumed;
+
+    FakeCharMsg()
+        : mCharCode(0),
+          mScanCode(0),
+          mIsSysKey(false),
+          mIsDeadKey(false),
+          mConsumed(false) {}
+
+    MSG GetCharMsg(HWND aWnd) const {
+      MSG msg;
+      msg.hwnd = aWnd;
+      msg.message = mIsDeadKey && mIsSysKey ? WM_SYSDEADCHAR
+                    : mIsDeadKey            ? WM_DEADCHAR
+                    : mIsSysKey             ? WM_SYSCHAR
+                                            : WM_CHAR;
+      msg.wParam = static_cast<WPARAM>(mCharCode);
+      msg.lParam = static_cast<LPARAM>(mScanCode << 16);
+      msg.time = 0;
+      msg.pt.x = msg.pt.y = 0;
+      return msg;
+    }
+  };
+
+  NativeKey(nsWindow* aWidget, const MSG& aMessage,
+            const ModifierKeyState& aModKeyState,
+            HKL aOverrideKeyboardLayout = 0,
+            nsTArray<FakeCharMsg>* aFakeCharMsgs = nullptr);
+
+  ~NativeKey();
+
+  /**
+   * Handle WM_KEYDOWN message or WM_SYSKEYDOWN message.  The instance must be
+   * initialized with WM_KEYDOWN or WM_SYSKEYDOWN.
+   * Returns true if dispatched keydown event or keypress event is consumed.
+   * Otherwise, false.
+   */
+  bool HandleKeyDownMessage(bool* aEventDispatched = nullptr) const;
+
+  /**
+   * Handles WM_CHAR message or WM_SYSCHAR message.  The instance must be
+   * initialized with them.
+   * Returns true if dispatched keypress event is consumed.  Otherwise, false.
+   */
+  bool HandleCharMessage(bool* aEventDispatched = nullptr) const;
+
+  /**
+   * Handles keyup message.  Returns true if the event is consumed.
+   * Otherwise, false.
+   */
+  bool HandleKeyUpMessage(bool* aEventDispatched = nullptr) const;
+
+  /**
+   * Handles WM_APPCOMMAND message.  Returns true if the event is consumed.
+   * Otherwise, false.
+   */
+  bool HandleAppCommandMessage() const;
+
+  /**
+   * Callback of TextEventDispatcherListener::WillDispatchKeyboardEvent().
+   * This method sets alternative char codes of aKeyboardEvent.
+   */
+  void WillDispatchKeyboardEvent(WidgetKeyboardEvent& aKeyboardEvent,
+                                 uint32_t aIndex);
+
+  /**
+   * Returns true if aChar is a control character which shouldn't be inputted
+   * into focused text editor.
+   */
+  static bool IsControlChar(char16_t aChar);
+
+  bool IsShift() const { return mModKeyState.IsShift(); }
+  bool IsControl() const { return mModKeyState.IsControl(); }
+  bool IsAlt() const { return mModKeyState.IsAlt(); }
+  bool MaybeEmulatingAltGraph() const;
+  Modifiers GetModifiers() const { return mModKeyState.GetModifiers(); }
+  const ModifierKeyState& ModifierKeyStateRef() const { return mModKeyState; }
+  VirtualKey::ShiftState GetShiftState() const {
+    return VirtualKey::ModifierKeyStateToShiftState(mModKeyState);
+  }
+
+  /**
+   * GenericVirtualKeyCode() returns virtual keycode which cannot distinguish
+   * position of modifier keys.  E.g., VK_CONTROL for both ControlLeft and
+   * ControlRight.
+   */
+  uint8_t GenericVirtualKeyCode() const { return mOriginalVirtualKeyCode; }
+
+  /**
+   * SpecificVirtualKeyCode() returns virtual keycode which can distinguish
+   * position of modifier keys.  E.g., returns VK_LCONTROL or VK_RCONTROL
+   * instead of VK_CONTROL.  If the key message is synthesized with not
+   * enough information, this prefers left position's keycode.
+   */
+  uint8_t SpecificVirtualKeyCode() const { return mVirtualKeyCode; }
+
+ private:
+  NativeKey* mLastInstance;
+  // mRemovingMsg is set at removing a char message from
+  // GetFollowingCharMessage().
+  MSG mRemovingMsg;
+  // mReceivedMsg is set when another instance starts to handle the message
+  // unexpectedly.
+  MSG mReceivedMsg;
+  RefPtr<nsWindow> mWidget;
+  RefPtr<TextEventDispatcher> mDispatcher;
+  HKL mKeyboardLayout;
+  MSG mMsg;
+  // mFollowingCharMsgs stores WM_CHAR, WM_SYSCHAR, WM_DEADCHAR or
+  // WM_SYSDEADCHAR message which follows WM_KEYDOWN.
+  // Note that the stored messaged are already removed from the queue.
+  // FYI: 5 is enough number for usual keyboard layout handling.  On Windows,
+  // a dead key sequence may cause inputting up to 5 characters per key press.
+  AutoTArray<MSG, 5> mFollowingCharMsgs;
+  // mRemovedOddCharMsgs stores WM_CHAR messages which are caused by ATOK or
+  // WXG (they are Japanese IME) when the user tries to do "Kakutei-undo"
+  // (it means "undo the last commit").
+  nsTArray<MSG> mRemovedOddCharMsgs;
+  // If dispatching eKeyDown or eKeyPress event causes focus change,
+  // the instance shouldn't handle remaning char messages.  For checking it,
+  // this should store first focused window.
+  HWND mFocusedWndBeforeDispatch;
+
+  uint32_t mDOMKeyCode;
+  KeyNameIndex mKeyNameIndex;
+  CodeNameIndex mCodeNameIndex;
+
+  ModifierKeyState mModKeyState;
+
+  // mVirtualKeyCode distinguishes left key or right key of modifier key.
+  uint8_t mVirtualKeyCode;
+  // mOriginalVirtualKeyCode doesn't distinguish left key or right key of
+  // modifier key.  However, if the given keycode is VK_PROCESS, it's resolved
+  // to a keycode before it's handled by IME.
+  uint8_t mOriginalVirtualKeyCode;
+
+  // mCommittedChars indicates the inputted characters which is committed by
+  // the key.  If dead key fail to composite a character, mCommittedChars
+  // indicates both the dead characters and the base characters.
+  UniCharsAndModifiers mCommittedCharsAndModifiers;
+
+  // Following strings are computed by
+  // ComputeInputtingStringWithKeyboardLayout() which is typically called
+  // before dispatching keydown event.
+  // mInputtingStringAndModifiers's string is the string to be
+  // inputted into the focused editor and its modifier state is proper
+  // modifier state for inputting the string into the editor.
+  UniCharsAndModifiers mInputtingStringAndModifiers;
+  // mShiftedString is the string to be inputted into the editor with
+  // current modifier state with active shift state.
+  UniCharsAndModifiers mShiftedString;
+  // mUnshiftedString is the string to be inputted into the editor with
+  // current modifier state without shift state.
+  UniCharsAndModifiers mUnshiftedString;
+  // Following integers are computed by
+  // ComputeInputtingStringWithKeyboardLayout() which is typically called
+  // before dispatching keydown event.  The meaning of these values is same
+  // as charCode.
+  uint32_t mShiftedLatinChar;
+  uint32_t mUnshiftedLatinChar;
+
+  WORD mScanCode;
+  bool mIsExtended;
+  // mIsRepeat is true if the key message is caused by the auto-repeat
+  // feature.
+  bool mIsRepeat;
+  bool mIsDeadKey;
+  // mIsPrintableKey is true if the key may be a printable key without
+  // any modifier keys.  Otherwise, false.
+  // Please note that the event may not cause any text input even if this
+  // is true.  E.g., it might be dead key state or Ctrl key may be pressed.
+  bool mIsPrintableKey;
+  // mIsSkippableInRemoteProcess is false if the key event shouldn't be
+  // skipped in the remote process even if it's too old event.
+  bool mIsSkippableInRemoteProcess;
+  // mCharMessageHasGone is true if the message is a keydown message and
+  // it's followed by at least one char message but it's gone at removing
+  // from the queue.  This could occur if PeekMessage() or something is
+  // hooked by odd tool.
+  bool mCharMessageHasGone;
+  // mIsOverridingKeyboardLayout is true if the instance temporarily overriding
+  // keyboard layout with specified by the constructor.
+  bool mIsOverridingKeyboardLayout;
+  // mCanIgnoreModifierStateAtKeyPress is true if it's allowed to remove
+  // Ctrl or Alt modifier state at dispatching eKeyPress.
+  bool mCanIgnoreModifierStateAtKeyPress;
+
+  nsTArray<FakeCharMsg>* mFakeCharMsgs;
+
+  // When a keydown event is dispatched at handling WM_APPCOMMAND, the computed
+  // virtual keycode is set to this.  Even if we consume WM_APPCOMMAND message,
+  // Windows may send WM_KEYDOWN and WM_KEYUP message for them.
+  // At that time, we should not dispatch key events for them.
+  static uint8_t sDispatchedKeyOfAppCommand;
+
+  NativeKey() {
+    MOZ_CRASH("The default constructor of NativeKey isn't available");
+  }
+
+  void InitWithAppCommand();
+  void InitWithKeyOrChar();
+
+  /**
+   * InitIsSkippableForKeyOrChar() initializes mIsSkippableInRemoteProcess with
+   * mIsRepeat and previous key message information.  So, this must be called
+   * after mIsRepeat is initialized.
+   */
+  void InitIsSkippableForKeyOrChar(const MSG& aLastKeyMSG);
+
+  /**
+   * InitCommittedCharsAndModifiersWithFollowingCharMessages() initializes
+   * mCommittedCharsAndModifiers with mFollowingCharMsgs and mModKeyState.
+   * If mFollowingCharMsgs includes non-printable char messages, they are
+   * ignored (skipped).
+   */
+  void InitCommittedCharsAndModifiersWithFollowingCharMessages();
+
+  UINT GetScanCodeWithExtendedFlag() const;
+
+  // The result is one of eKeyLocation*.
+  uint32_t GetKeyLocation() const;
+
+  /**
+   * RemoveFollowingOddCharMessages() removes odd WM_CHAR messages from the
+   * queue when IsIMEDoingKakuteiUndo() returns true.
+   */
+  void RemoveFollowingOddCharMessages();
+
+  /**
+   * "Kakutei-Undo" of ATOK or WXG (both of them are Japanese IME) causes
+   * strange WM_KEYDOWN/WM_KEYUP/WM_CHAR message pattern.  So, when this
+   * returns true, the caller needs to be careful for processing the messages.
+   */
+  bool IsIMEDoingKakuteiUndo() const;
+
+  /**
+   * This returns true if user types a number key in numpad with Alt key
+   * to input a Unicode character from its scalar value.
+   * Note that inputting Unicode scalar value is available without NumLock.
+   * Therefore, this returns true even if user presses a function key on
+   * numpad without NumLock, but that may be intended to perform a shortcut
+   * key like Alt + Home.
+   */
+  bool MaybeTypingUnicodeScalarValue() const {
+    return !mIsExtended && IsSysKeyDownOrKeyUpMessage() && IsAlt() &&
+           !IsControl() && !IsShift() &&
+           ((mScanCode >= 0x004F && mScanCode <= 0x0052) ||  // Numpad0-3
+            (mScanCode >= 0x004B && mScanCode <= 0x004D) ||  // Numpad4-6
+            (mScanCode >= 0x0047 && mScanCode <= 0x0049));   // Numpad7-9
+  }
+
+  bool IsKeyDownMessage() const {
+    return mMsg.message == WM_KEYDOWN || mMsg.message == WM_SYSKEYDOWN;
+  }
+  bool IsKeyUpMessage() const {
+    return mMsg.message == WM_KEYUP || mMsg.message == WM_SYSKEYUP;
+  }
+  bool IsSysKeyDownOrKeyUpMessage() const {
+    return mMsg.message == WM_SYSKEYDOWN || mMsg.message == WM_SYSKEYUP;
+  }
+  bool IsCharOrSysCharMessage(const MSG& aMSG) const {
+    return IsCharOrSysCharMessage(aMSG.message);
+  }
+  bool IsCharOrSysCharMessage(UINT aMessage) const {
+    return (aMessage == WM_CHAR || aMessage == WM_SYSCHAR);
+  }
+  bool IsCharMessage(const MSG& aMSG) const {
+    return IsCharMessage(aMSG.message);
+  }
+  bool IsCharMessage(UINT aMessage) const {
+    return (IsCharOrSysCharMessage(aMessage) || IsDeadCharMessage(aMessage));
+  }
+  bool IsDeadCharMessage(const MSG& aMSG) const {
+    return IsDeadCharMessage(aMSG.message);
+  }
+  bool IsDeadCharMessage(UINT aMessage) const {
+    return (aMessage == WM_DEADCHAR || aMessage == WM_SYSDEADCHAR);
+  }
+  bool IsSysCharMessage(const MSG& aMSG) const {
+    return IsSysCharMessage(aMSG.message);
+  }
+  bool IsSysCharMessage(UINT aMessage) const {
+    return (aMessage == WM_SYSCHAR || aMessage == WM_SYSDEADCHAR);
+  }
+  bool MayBeSameCharMessage(const MSG& aCharMsg1, const MSG& aCharMsg2) const;
+  bool IsSamePhysicalKeyMessage(const MSG& aKeyOrCharMsg1,
+                                const MSG& aKeyOrCharMsg2) const;
+  bool IsFollowedByPrintableCharMessage() const;
+  bool IsFollowedByPrintableCharOrSysCharMessage() const;
+  bool IsFollowedByDeadCharMessage() const;
+  bool IsPrintableCharMessage(const MSG& aMSG) const {
+    return aMSG.message == WM_CHAR &&
+           !IsControlChar(static_cast<char16_t>(aMSG.wParam));
+  }
+  bool IsEnterKeyPressCharMessage(const MSG& aMSG) const {
+    return aMSG.message == WM_CHAR && aMSG.wParam == '\r';
+  }
+  bool IsPrintableCharOrSysCharMessage(const MSG& aMSG) const {
+    return IsCharOrSysCharMessage(aMSG) &&
+           !IsControlChar(static_cast<char16_t>(aMSG.wParam));
+  }
+  bool IsControlCharMessage(const MSG& aMSG) const {
+    return IsCharMessage(aMSG.message) &&
+           IsControlChar(static_cast<char16_t>(aMSG.wParam));
+  }
+
+  /**
+   * IsReservedBySystem() returns true if the key combination is reserved by
+   * the system.  Even if it's consumed by web apps, the message should be
+   * sent to next wndproc.
+   */
+  bool IsReservedBySystem() const;
+
+  /**
+   * GetFollowingCharMessage() returns following char message of handling
+   * keydown event.  If the message is found, this method returns true.
+   * Otherwise, returns false.
+   *
+   * WARNING: Even if this returns true, aCharMsg may be WM_NULL or its
+   *          hwnd may be different window.
+   */
+  bool GetFollowingCharMessage(MSG& aCharMsg);
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK.
+   */
+  uint8_t ComputeVirtualKeyCodeFromScanCode() const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK_EX.
+   */
+  uint8_t ComputeVirtualKeyCodeFromScanCodeEx() const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VK_TO_VSC_EX or MAPVK_VK_TO_VSC.
+   */
+  uint16_t ComputeScanCodeExFromVirtualKeyCode(UINT aVirtualKeyCode) const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK and MAPVK_VK_TO_CHAR.
+   */
+  char16_t ComputeUnicharFromScanCode() const;
+
+  /**
+   * Initializes the aKeyEvent with the information stored in the instance.
+   */
+  nsEventStatus InitKeyEvent(WidgetKeyboardEvent& aKeyEvent,
+                             const ModifierKeyState& aModKeyState) const;
+  nsEventStatus InitKeyEvent(WidgetKeyboardEvent& aKeyEvent) const;
+
+  /**
+   * Dispatches a command event for aEventCommand.
+   * Returns true if the event is consumed.  Otherwise, false.
+   */
+  bool DispatchCommandEvent(uint32_t aEventCommand) const;
+
+  /**
+   * DispatchKeyPressEventsWithRetrievedCharMessages() dispatches keypress
+   * event(s) with retrieved char messages.
+   */
+  bool DispatchKeyPressEventsWithRetrievedCharMessages() const;
+
+  /**
+   * DispatchKeyPressEventsWithoutCharMessage() dispatches keypress event(s)
+   * without char messages.  So, this should be used only when there are no
+   * following char messages.
+   */
+  bool DispatchKeyPressEventsWithoutCharMessage() const;
+
+  /**
+   * Checkes whether the key event down message is handled without following
+   * WM_CHAR messages.  For example, if following WM_CHAR message indicates
+   * control character input, the WM_CHAR message is unclear whether it's
+   * caused by a printable key with Ctrl or just a function key such as Enter
+   * or Backspace.
+   */
+  bool NeedsToHandleWithoutFollowingCharMessages() const;
+
+  /**
+   * ComputeInputtingStringWithKeyboardLayout() computes string to be inputted
+   * with the key and the modifier state, without shift state and with shift
+   * state.
+   */
+  void ComputeInputtingStringWithKeyboardLayout();
+
+  /**
+   * IsFocusedWindowChanged() returns true if focused window is changed
+   * after the instance is created.
+   */
+  bool IsFocusedWindowChanged() const {
+    return mFocusedWndBeforeDispatch != ::GetFocus();
+  }
+
+  /**
+   * Handles WM_CHAR message or WM_SYSCHAR message.  The instance must be
+   * initialized with WM_KEYDOWN, WM_SYSKEYDOWN or them.
+   * Returns true if dispatched keypress event is consumed.  Otherwise, false.
+   */
+  bool HandleCharMessage(const MSG& aCharMsg,
+                         bool* aEventDispatched = nullptr) const;
+
+  // Calls of PeekMessage() from NativeKey might cause nested message handling
+  // due to (perhaps) odd API hook.  NativeKey should do nothing if given
+  // message is tried to be retrieved by another instance.
+
+  /**
+   * sLatestInstacne is a pointer to the newest instance of NativeKey which is
+   * handling a key or char message(s).
+   */
+  static NativeKey* sLatestInstance;
+
+  static const MSG sEmptyMSG;
+
+  static MSG sLastKeyOrCharMSG;
+
+  static MSG sLastKeyMSG;
+
+  static bool IsEmptyMSG(const MSG& aMSG) {
+    return !memcmp(&aMSG, &sEmptyMSG, sizeof(MSG));
+  }
+
+  bool IsAnotherInstanceRemovingCharMessage() const {
+    return mLastInstance && !IsEmptyMSG(mLastInstance->mRemovingMsg);
+  }
+
+ public:
+  /**
+   * Returns last key or char MSG.  If no MSG has been received yet, the result
+   * is empty MSG (i.e., .message is WM_NULL).
+   */
+  static const MSG& LastKeyOrCharMSG() { return sLastKeyOrCharMSG; }
+};
+
+class KeyboardLayout {
+ public:
+  static KeyboardLayout* GetInstance();
+  static void Shutdown();
+  static HKL GetActiveLayout();
+  static nsCString GetActiveLayoutName();
+  static void NotifyIdleServiceOfUserActivity();
+
+  static bool IsPrintableCharKey(uint8_t aVirtualKey);
+
+  /**
+   * HasAltGr() returns true if the keyboard layout's AltRight key is AltGr
+   * key.
+   */
+  bool HasAltGr() const { return mHasAltGr; }
+
+  /**
+   * IsDeadKey() returns true if aVirtualKey is a dead key with aModKeyState.
+   * This method isn't stateful.
+   */
+  bool IsDeadKey(uint8_t aVirtualKey,
+                 const ModifierKeyState& aModKeyState) const;
+  bool IsDeadKey(const NativeKey& aNativeKey) const {
+    return IsDeadKey(aNativeKey.GenericVirtualKeyCode(),
+                     aNativeKey.ModifierKeyStateRef());
+  }
+
+  /**
+   * IsInDeadKeySequence() returns true when it's in a dead key sequence.
+   * It starts when a dead key is down and ends when another key down causes
+   * inactivating the dead key state.
+   */
+  bool IsInDeadKeySequence() const { return !mActiveDeadKeys.IsEmpty(); }
+
+  /**
+   * IsSysKey() returns true if aVirtualKey with aModKeyState causes WM_SYSKEY*
+   * or WM_SYS*CHAR messages.
+   */
+  bool IsSysKey(uint8_t aVirtualKey,
+                const ModifierKeyState& aModKeyState) const;
+  bool IsSysKey(const NativeKey& aNativeKey) const {
+    return IsSysKey(aNativeKey.GenericVirtualKeyCode(),
+                    aNativeKey.ModifierKeyStateRef());
+  }
+
+  /**
+   * GetUniCharsAndModifiers() returns characters which are inputted by
+   * aVirtualKey with aModKeyState.  This method isn't stateful.
+   * Note that if the combination causes text input, the result's Ctrl and
+   * Alt key state are never active.
+   */
+  UniCharsAndModifiers GetUniCharsAndModifiers(
+      uint8_t aVirtualKey, const ModifierKeyState& aModKeyState) const {
+    VirtualKey::ShiftState shiftState =
+        VirtualKey::ModifierKeyStateToShiftState(aModKeyState);
+    return GetUniCharsAndModifiers(aVirtualKey, shiftState);
+  }
+  UniCharsAndModifiers GetUniCharsAndModifiers(
+      const NativeKey& aNativeKey) const {
+    return GetUniCharsAndModifiers(aNativeKey.GenericVirtualKeyCode(),
+                                   aNativeKey.GetShiftState());
+  }
+
+  /**
+   * OnLayoutChange() must be called before the first keydown message is
+   * received.  LoadLayout() changes the keyboard state, that causes breaking
+   * dead key state.  Therefore, we need to load the layout before the first
+   * keydown message.
+   */
+  void OnLayoutChange(HKL aKeyboardLayout) {
+    MOZ_ASSERT(!mIsOverridden);
+    LoadLayout(aKeyboardLayout);
+  }
+
+  /**
+   * OverrideLayout() loads the specified keyboard layout.
+   */
+  void OverrideLayout(HKL aLayout) {
+    mIsOverridden = true;
+    LoadLayout(aLayout);
+  }
+
+  /**
+   * RestoreLayout() loads the current keyboard layout of the thread.
+   */
+  void RestoreLayout() {
+    mIsOverridden = false;
+    mIsPendingToRestoreKeyboardLayout = true;
+  }
+
+  uint32_t ConvertNativeKeyCodeToDOMKeyCode(UINT aNativeKeyCode) const;
+
+  /**
+   * ConvertNativeKeyCodeToKeyNameIndex() returns KeyNameIndex value for
+   * non-printable keys (except some special keys like space key).
+   */
+  KeyNameIndex ConvertNativeKeyCodeToKeyNameIndex(uint8_t aVirtualKey) const;
+
+  /**
+   * ConvertScanCodeToCodeNameIndex() returns CodeNameIndex value for
+   * the given scan code.  aScanCode can be over 0xE000 since this method
+   * doesn't use Windows API.
+   */
+  static CodeNameIndex ConvertScanCodeToCodeNameIndex(UINT aScanCode);
+
+  HKL GetLayout() const {
+    return mIsPendingToRestoreKeyboardLayout ? ::GetKeyboardLayout(0)
+                                             : mKeyboardLayout;
+  }
+
+  /**
+   * This wraps MapVirtualKeyEx() API with MAPVK_VK_TO_VSC.
+   */
+  WORD ComputeScanCodeForVirtualKeyCode(uint8_t aVirtualKeyCode) const;
+
+  /**
+   * Implementation of nsIWidget::SynthesizeNativeKeyEvent().
+   */
+  nsresult SynthesizeNativeKeyEvent(nsWindow* aWidget,
+                                    int32_t aNativeKeyboardLayout,
+                                    int32_t aNativeKeyCode,
+                                    uint32_t aModifierFlags,
+                                    const nsAString& aCharacters,
+                                    const nsAString& aUnmodifiedCharacters);
+
+ private:
+  KeyboardLayout();
+  ~KeyboardLayout();
+
+  static KeyboardLayout* sInstance;
+  static nsIUserIdleServiceInternal* sIdleService;
+
+  struct DeadKeyTableListEntry {
+    DeadKeyTableListEntry* next;
+    uint8_t data[1];
+  };
+
+  HKL mKeyboardLayout;
+
+  VirtualKey mVirtualKeys[NS_NUM_OF_KEYS];
+  DeadKeyTableListEntry* mDeadKeyTableListHead;
+  // When mActiveDeadKeys is empty, it's not in dead key sequence.
+  // Otherwise, it contains virtual keycodes which are pressed in current
+  // dead key sequence.
+  nsTArray<uint8_t> mActiveDeadKeys;
+  // mDeadKeyShiftStates is always same length as mActiveDeadKeys.
+  // This stores shift states at pressing each dead key stored in
+  // mActiveDeadKeys.
+  nsTArray<VirtualKey::ShiftState> mDeadKeyShiftStates;
+
+  bool mIsOverridden;
+  bool mIsPendingToRestoreKeyboardLayout;
+  bool mHasAltGr;
+
+  static inline int32_t GetKeyIndex(uint8_t aVirtualKey);
+  static int CompareDeadKeyEntries(const void* aArg1, const void* aArg2,
+                                   void* aData);
+  static bool AddDeadKeyEntry(char16_t aBaseChar, char16_t aCompositeChar,
+                              DeadKeyEntry* aDeadKeyArray, uint32_t aEntries);
+  bool EnsureDeadKeyActive(bool aIsActive, uint8_t aDeadKey,
+                           const PBYTE aDeadKeyKbdState);
+  uint32_t GetDeadKeyCombinations(uint8_t aDeadKey,
+                                  const PBYTE aDeadKeyKbdState,
+                                  uint16_t aShiftStatesWithBaseChars,
+                                  DeadKeyEntry* aDeadKeyArray,
+                                  uint32_t aMaxEntries);
+  /**
+   * Activates or deactivates dead key state.
+   */
+  void ActivateDeadKeyState(const NativeKey& aNativeKey);
+  void DeactivateDeadKeyState();
+
+  const DeadKeyTable* AddDeadKeyTable(const DeadKeyEntry* aDeadKeyArray,
+                                      uint32_t aEntries);
+  void ReleaseDeadKeyTables();
+
+  /**
+   * Loads the specified keyboard layout. This method always clear the dead key
+   * state.
+   */
+  void LoadLayout(HKL aLayout);
+
+  /**
+   * Gets the keyboard layout name of aLayout.  Be careful, this may be too
+   * slow to call at handling user input.
+   */
+  nsCString GetLayoutName(HKL aLayout) const;
+
+  /**
+   * InitNativeKey() must be called when actually widget receives WM_KEYDOWN or
+   * WM_KEYUP.  This method is stateful.  This saves current dead key state at
+   * WM_KEYDOWN.  Additionally, computes current inputted character(s) and set
+   * them to the aNativeKey.
+   */
+  void InitNativeKey(NativeKey& aNativeKey);
+
+  /**
+   * MaybeInitNativeKeyAsDeadKey() initializes aNativeKey only when aNativeKey
+   * is a dead key's event.
+   * When it's not in a dead key sequence, this activates the dead key state.
+   * When it's in a dead key sequence, this initializes aNativeKey with a
+   * composite character or a preceding dead char and a dead char which should
+   * be caused by aNativeKey.
+   * Returns true when this initializes aNativeKey.  Otherwise, false.
+   */
+  bool MaybeInitNativeKeyAsDeadKey(NativeKey& aNativeKey);
+
+  /**
+   * MaybeInitNativeKeyWithCompositeChar() may initialize aNativeKey with
+   * proper composite character when dead key produces a composite character.
+   * Otherwise, just returns false.
+   */
+  bool MaybeInitNativeKeyWithCompositeChar(NativeKey& aNativeKey);
+
+  /**
+   * See the comment of GetUniCharsAndModifiers() below.
+   */
+  UniCharsAndModifiers GetUniCharsAndModifiers(
+      uint8_t aVirtualKey, VirtualKey::ShiftState aShiftState) const;
+
+  /**
+   * GetDeadUniCharsAndModifiers() returns dead chars which are stored in
+   * current dead key sequence.  So, this is stateful.
+   */
+  UniCharsAndModifiers GetDeadUniCharsAndModifiers() const;
+
+  /**
+   * GetCompositeChar() returns a composite character with dead character
+   * caused by mActiveDeadKeys, mDeadKeyShiftStates and a base character
+   * (aBaseChar).
+   * If the combination of the dead character and the base character doesn't
+   * cause a composite character, this returns 0.
+   */
+  char16_t GetCompositeChar(char16_t aBaseChar) const;
+
+  // NativeKey class should access InitNativeKey() directly, but it shouldn't
+  // be available outside of NativeKey.  So, let's make NativeKey a friend
+  // class of this.
+  friend class NativeKey;
+};
+
+class RedirectedKeyDownMessageManager {
+ public:
+  /*
+   * If a window receives WM_KEYDOWN message or WM_SYSKEYDOWM message which is
+   * a redirected message, NativeKey::DispatchKeyDownAndKeyPressEvent()
+   * prevents to dispatch eKeyDown event because it has been dispatched
+   * before the message was redirected.  However, in some cases, WM_*KEYDOWN
+   * message handler may not handle actually.  Then, the message handler needs
+   * to forget the redirected message and remove WM_CHAR message or WM_SYSCHAR
+   * message for the redirected keydown message.  AutoFlusher class is a helper
+   * class for doing it.  This must be created in the stack.
+   */
+  class MOZ_STACK_CLASS AutoFlusher final {
+   public:
+    AutoFlusher(nsWindow* aWidget, const MSG& aMsg)
+        : mCancel(!RedirectedKeyDownMessageManager::IsRedirectedMessage(aMsg)),
+          mWidget(aWidget),
+          mMsg(aMsg) {}
+
+    ~AutoFlusher() {
+      if (mCancel) {
+        return;
+      }
+      // Prevent unnecessary keypress event
+      if (!mWidget->Destroyed()) {
+        RedirectedKeyDownMessageManager::RemoveNextCharMessage(mMsg.hwnd);
+      }
+      // Foreget the redirected message
+      RedirectedKeyDownMessageManager::Forget();
+    }
+
+    void Cancel() { mCancel = true; }
+
+   private:
+    bool mCancel;
+    RefPtr<nsWindow> mWidget;
+    const MSG& mMsg;
+  };
+
+  static void WillRedirect(const MSG& aMsg, bool aDefualtPrevented) {
+    sRedirectedKeyDownMsg = aMsg;
+    sDefaultPreventedOfRedirectedMsg = aDefualtPrevented;
+  }
+
+  static void Forget() { sRedirectedKeyDownMsg.message = WM_NULL; }
+
+  static void PreventDefault() { sDefaultPreventedOfRedirectedMsg = true; }
+  static bool DefaultPrevented() { return sDefaultPreventedOfRedirectedMsg; }
+
+  static bool IsRedirectedMessage(const MSG& aMsg);
+
+  /**
+   * RemoveNextCharMessage() should be called by WM_KEYDOWN or WM_SYSKEYDOWM
+   * message handler.  If there is no WM_(SYS)CHAR message for it, this
+   * method does nothing.
+   * NOTE: WM_(SYS)CHAR message is posted by TranslateMessage() API which is
+   * called in message loop.  So, WM_(SYS)KEYDOWN message should have
+   * WM_(SYS)CHAR message in the queue if the keydown event causes character
+   * input.
+   */
+  static void RemoveNextCharMessage(HWND aWnd);
+
+ private:
+  // sRedirectedKeyDownMsg is WM_KEYDOWN message or WM_SYSKEYDOWN message which
+  // is reirected with SendInput() API by
+  // widget::NativeKey::DispatchKeyDownAndKeyPressEvent()
+  static MSG sRedirectedKeyDownMsg;
+  static bool sDefaultPreventedOfRedirectedMsg;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif