Bug 1615977 - Don't modify key value while pressing a numpad key with `Alt` but the virtual keycode is a function key r=m_kato
authorMasayuki Nakano <masayuki@d-toybox.com>
Thu, 27 Feb 2020 03:21:36 +0000
changeset 515824 eb02d91fd3b8cbe8cf7b6356eac45123b9ee50de
parent 515823 7fc17499b72099c0fa5d27f76c619229c01f2516
child 515825 b3dfa17c6305c657f8c3b3c95121c19f005d451c
push id37162
push usernbeleuzu@mozilla.com
push dateThu, 27 Feb 2020 09:49:56 +0000
treeherdermozilla-central@9e8d5431c412 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
bugs1615977, 1606655
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Bug 1615977 - Don't modify key value while pressing a numpad key with `Alt` but the virtual keycode is a function key r=m_kato Inputting Unicode scalar value with `Alt` + numpad keys is available even without NumLock state. However, `Alt` + function key on numpad should also be worked because user may intent to perform it. Therefore, this patch stops the hacking for bug 1606655 when given virtual keycode value is a function key, but this means that users cannot type a Unicode scalar value without NumLock key state if the value includes `7` (`Home`), `4` (`ArrowLeft`), `6` (`ArrowRight`) because Firefox UI handles they are shortcut keys (for "Go home", "Go back" and "Go forward"). Unfortunately, I have no idea how to solve this conflict (if it's second key or latter key after pressing `Alt` key, we could do that with a boolean flag, but I don't like to make it only for this kind of edge case unless a lot of users want to do it). Differential Revision: https://phabricator.services.mozilla.com/D63782
--- a/widget/windows/KeyboardLayout.cpp
+++ b/widget/windows/KeyboardLayout.cpp
@@ -3490,22 +3490,28 @@ void NativeKey::ComputeInputtingStringWi
   // If user is inputting a Unicode character with typing Alt + Numpad
   // keys, we shouldn't set alternative key codes because the key event
   // shouldn't match with a mnemonic.  However, we should set only
   // mUnshiftedString for keeping traditional behavior at WM_SYSKEYDOWN.
   // FYI: I guess that it's okay that mUnshiftedString stays empty.  So,
   //      if its value breaks something, you must be able to just return here.
-  if (IsTypingUnicodeScalarValue()) {
-    MOZ_ASSERT(mMsg.message == WM_SYSKEYDOWN);
-    MOZ_ASSERT(!mCommittedCharsAndModifiers.IsEmpty());
-    char16_t num = mCommittedCharsAndModifiers.CharAt(0);
-    MOZ_ASSERT(num >= '0' && num <= '9');
-    mUnshiftedString.Append(num, MODIFIER_NONE);
+  if (MaybeTypingUnicodeScalarValue()) {
+    if (!mCommittedCharsAndModifiers.IsEmpty()) {
+      MOZ_ASSERT(mMsg.message == WM_SYSKEYDOWN);
+      char16_t num = mCommittedCharsAndModifiers.CharAt(0);
+      MOZ_ASSERT(num >= '0' && num <= '9');
+      mUnshiftedString.Append(num, MODIFIER_NONE);
+      return;
+    }
+    // If user presses a function key without NumLock or 3rd party utility
+    // synthesizes a function key on numpad, we should handle it as-is because
+    // the user's intention may be performing `Alt` + foo.
+    MOZ_ASSERT(!KeyboardLayout::IsPrintableCharKey(mVirtualKeyCode));
   ModifierKeyState capsLockState(mModKeyState.GetModifiers() &
   mUnshiftedString =
       keyboardLayout->GetUniCharsAndModifiers(mVirtualKeyCode, capsLockState);
@@ -3979,17 +3985,25 @@ void KeyboardLayout::InitNativeKey(Nativ
   // If the aNativeKey is in a sequence to input a Unicode character with
   // Alt + numpad keys, we should just set the number as the inputting charcter.
   // Note that we should compute the key value from the virtual key code
   // because they may be mapped to alphabets, but they should be treated as
   // Alt + [0-9] even by web apps.
-  if (aNativeKey.IsTypingUnicodeScalarValue()) {
+  // However, we shouldn't touch the key value if given virtual key code is
+  // not a printable key because it may be synthesized by 3rd party utility
+  // or just NumLock is unlocked and user tries to use shortcut key.  In the
+  // latter case, we cannot solve the conflict issue with Alt+foo shortcut key
+  // and inputting a Unicode scalar value like reported to bug 1606655, though,
+  // I have no better idea.  Perhaps, `Alt` shouldn't be used for shortcut key
+  // combination on Windows.
+  if (aNativeKey.MaybeTypingUnicodeScalarValue() &&
+      KeyboardLayout::IsPrintableCharKey(aNativeKey.mVirtualKeyCode)) {
     // If the key code value is mapped to a Numpad key, let's compute the key
     // value with it.  This is same behavior as Chrome.  In strictly speaking,
     // I think that the else block's computation is better because it seems
     // that Windows does not refer virtual key code value, but we should avoid
     // web-compat issues.
     char16_t num = '0';
     if (aNativeKey.mVirtualKeyCode >= VK_NUMPAD0 &&
         aNativeKey.mVirtualKeyCode <= VK_NUMPAD9) {
--- a/widget/windows/KeyboardLayout.h
+++ b/widget/windows/KeyboardLayout.h
@@ -603,18 +603,22 @@ class MOZ_STACK_CLASS NativeKey final {
    * 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 IsTypingUnicodeScalarValue() const {
+  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 {