packages/flutter/lib/src/services/raw_keyboard_macos.dart - mirrors/flutter - Git at Google

 // Copyright 2014 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'package:flutter/foundation.dart';

 import 'keyboard_key.dart';
 import 'keyboard_maps.dart';
 import 'raw_keyboard.dart';

 /// Platform-specific key event data for macOS.
 ///
 /// This object contains information about key events obtained from macOS's
 /// `NSEvent` interface.
 ///
 /// See also:
 ///
 ///  * [RawKeyboard], which uses this interface to expose key data.
 class RawKeyEventDataMacOs extends RawKeyEventData {
   /// Creates a key event data structure specific for macOS.
   ///
   /// The [characters], [charactersIgnoringModifiers], and [modifiers], arguments
   /// must not be null.
   const RawKeyEventDataMacOs({
     this.characters = '',
     this.charactersIgnoringModifiers = '',
     this.keyCode = 0,
     this.modifiers = 0,
   }) : assert(characters != null),
        assert(charactersIgnoringModifiers != null),
        assert(keyCode != null),
        assert(modifiers != null);

   /// The Unicode characters associated with a key-up or key-down event.
   ///
   /// See also:
   ///
   ///  * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1534183-characters?language=objc)
   final String characters;

   /// The characters generated by a key event as if no modifier key (except for
   /// Shift) applies.
   ///
   /// See also:
   ///
   ///  * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1524605-charactersignoringmodifiers?language=objc)
   final String charactersIgnoringModifiers;

   /// The virtual key code for the keyboard key associated with a key event.
   ///
   /// See also:
   ///
   ///  * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1534513-keycode?language=objc)
   final int keyCode;

   /// A mask of the current modifiers using the values in Modifier Flags.
   ///
   /// See also:
   ///
   ///  * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1535211-modifierflags?language=objc)
   final int modifiers;

   @override
   String get keyLabel => charactersIgnoringModifiers.isEmpty ? null : charactersIgnoringModifiers;

   @override
   PhysicalKeyboardKey get physicalKey => kMacOsToPhysicalKey[keyCode] ?? PhysicalKeyboardKey.none;

   @override
   LogicalKeyboardKey get logicalKey {
     // Look to see if the keyCode is a printable number pad key, so that a
     // difference between regular keys (e.g. "=") and the number pad version
     // (e.g. the "=" on the number pad) can be determined.
     final LogicalKeyboardKey numPadKey = kMacOsNumPadMap[keyCode];
     if (numPadKey != null) {
       return numPadKey;
     }
     // If this key is printable, generate the LogicalKeyboardKey from its Unicode value.
     // Control keys such as ESC, CRTL, and SHIFT are not printable. HOME, DEL, arrow keys, and function
     // keys are considered modifier function keys, which generate invalid Unicode scalar values.
     if (keyLabel != null &&
         !LogicalKeyboardKey.isControlCharacter(keyLabel) &&
         !_isUnprintableKey(keyLabel)) {
       // Given that charactersIgnoringModifiers can contain a String of arbitrary length,
       // limit to a maximum of two Unicode scalar values. It is unlikely that a keyboard would produce a code point
       // bigger than 32 bits, but it is still worth defending against this case.
       assert(charactersIgnoringModifiers.length <= 2);
       int codeUnit = charactersIgnoringModifiers.codeUnitAt(0);
       if (charactersIgnoringModifiers.length == 2) {
         final int secondCode = charactersIgnoringModifiers.codeUnitAt(1);
         codeUnit = (codeUnit << 16) | secondCode;
       }

       final int keyId = LogicalKeyboardKey.unicodePlane | (codeUnit & LogicalKeyboardKey.valueMask);
       return LogicalKeyboardKey.findKeyByKeyId(keyId) ?? LogicalKeyboardKey(
         keyId,
         keyLabel: keyLabel,
         debugName: kReleaseMode ? null : 'Key ${keyLabel.toUpperCase()}',
       );
     }

     // Control keys like "backspace" and movement keys like arrow keys don't have a printable representation,
     // but are present on the physical keyboard. Since there is no logical keycode map for macOS
     // (macOS uses the keycode to reference physical keys), a LogicalKeyboardKey is created with
     // the physical key's HID usage and debugName. This avoids duplicating the physical
     // key map.
     if (physicalKey != PhysicalKeyboardKey.none) {
       final int keyId = physicalKey.usbHidUsage | LogicalKeyboardKey.hidPlane;
       return LogicalKeyboardKey.findKeyByKeyId(keyId) ?? LogicalKeyboardKey(
         keyId,
         keyLabel: physicalKey.debugName,
         debugName: physicalKey.debugName,
       );
     }

     // This is a non-printable key that is unrecognized, so a new code is minted
     // with the autogenerated bit set.
     const int macOsKeyIdPlane = 0x00500000000;

     return LogicalKeyboardKey(
       macOsKeyIdPlane | keyCode | LogicalKeyboardKey.autogeneratedMask,
       debugName: kReleaseMode ? null : 'Unknown macOS key code $keyCode',
     );
   }

   bool _isLeftRightModifierPressed(KeyboardSide side, int anyMask, int leftMask, int rightMask) {
     if (modifiers & anyMask == 0) {
       return false;
     }
     // If only the "anyMask" bit is set, then we respond true for requests of
     // whether either left or right is pressed.
     // Handles the case where macOS supplies just the "either" modifier flag,
     // but not the left/right flag. (e.g. modifierShift but not
     // modifierLeftShift).
     final bool anyOnly = modifiers & (leftMask | rightMask | anyMask) == anyMask;
     switch (side) {
       case KeyboardSide.any:
         return true;
       case KeyboardSide.all:
         return modifiers & leftMask != 0 && modifiers & rightMask != 0 || anyOnly;
       case KeyboardSide.left:
         return modifiers & leftMask != 0 || anyOnly;
       case KeyboardSide.right:
         return modifiers & rightMask != 0 || anyOnly;
     }
     return false;
   }

   @override
   bool isModifierPressed(ModifierKey key, {KeyboardSide side = KeyboardSide.any}) {
     final int independentModifier = modifiers & deviceIndependentMask;
     bool result;
     switch (key) {
       case ModifierKey.controlModifier:
         result = _isLeftRightModifierPressed(side, independentModifier & modifierControl, modifierLeftControl, modifierRightControl);
         break;
       case ModifierKey.shiftModifier:
         result = _isLeftRightModifierPressed(side, independentModifier & modifierShift, modifierLeftShift, modifierRightShift);
         break;
       case ModifierKey.altModifier:
         result = _isLeftRightModifierPressed(side, independentModifier & modifierOption, modifierLeftOption, modifierRightOption);
         break;
       case ModifierKey.metaModifier:
         result = _isLeftRightModifierPressed(side, independentModifier & modifierCommand, modifierLeftCommand, modifierRightCommand);
         break;
       case ModifierKey.capsLockModifier:
         result = independentModifier & modifierCapsLock != 0;
         break;
     // On macOS, the function modifier bit is set for any function key, like F1,
     // F2, etc., but the meaning of ModifierKey.modifierFunction in Flutter is
     // that of the Fn modifier key, so there's no good way to emulate that on
     // macOS.
       case ModifierKey.functionModifier:
       case ModifierKey.numLockModifier:
       case ModifierKey.symbolModifier:
       case ModifierKey.scrollLockModifier:
         // These modifier masks are not used in macOS keyboards.
         result = false;
         break;
     }
     assert(!result || getModifierSide(key) != null, "$runtimeType thinks that a modifier is pressed, but can't figure out what side it's on.");
     return result;
   }

   @override
   KeyboardSide getModifierSide(ModifierKey key) {
     KeyboardSide findSide(int leftMask, int rightMask, int anyMask) {
       final int combinedMask = leftMask | rightMask;
       final int combined = modifiers & combinedMask;
       if (combined == leftMask) {
         return KeyboardSide.left;
       } else if (combined == rightMask) {
         return KeyboardSide.right;
       } else if (combined == combinedMask || modifiers & (combinedMask | anyMask) == anyMask) {
         // Handles the case where macOS supplies just the "either" modifier
         // flag, but not the left/right flag. (e.g. modifierShift but not
         // modifierLeftShift).
         return KeyboardSide.all;
       }
       return null;
     }

     switch (key) {
       case ModifierKey.controlModifier:
         return findSide(modifierLeftControl, modifierRightControl, modifierControl);
       case ModifierKey.shiftModifier:
         return findSide(modifierLeftShift, modifierRightShift, modifierShift);
       case ModifierKey.altModifier:
         return findSide(modifierLeftOption, modifierRightOption, modifierOption);
       case ModifierKey.metaModifier:
         return findSide(modifierLeftCommand, modifierRightCommand, modifierCommand);
       case ModifierKey.capsLockModifier:
       case ModifierKey.numLockModifier:
       case ModifierKey.scrollLockModifier:
       case ModifierKey.functionModifier:
       case ModifierKey.symbolModifier:
         return KeyboardSide.all;
     }

     assert(false, 'Not handling $key type properly.');
     return null;
   }

   /// Returns true if the given label represents an unprintable key.
   ///
   /// Examples of unprintable keys are "NSUpArrowFunctionKey = 0xF700"
   /// or "NSHomeFunctionKey = 0xF729".
   ///
   /// See <https://developer.apple.com/documentation/appkit/1535851-function-key_unicodes?language=objc> for more
   /// information.
   ///
   /// Used by [RawKeyEvent] subclasses to help construct IDs.
   static bool _isUnprintableKey(String label) {
     if (label.length > 1) {
       return false;
     }
     final int codeUnit = label.codeUnitAt(0);
     return codeUnit >= 0xF700 && codeUnit <= 0xF8FF;
   }

   // Modifier key masks. See Apple's NSEvent documentation
   // https://developer.apple.com/documentation/appkit/nseventmodifierflags?language=objc
   // https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-86/IOHIDSystem/IOKit/hidsystem/IOLLEvent.h.auto.html

   /// This mask is used to check the [modifiers] field to test whether the CAPS
   /// LOCK modifier key is on.
   ///
   /// {@template flutter.services.rawKeyEventDataMacOs.modifiers}
   /// Use this value if you need to decode the [modifiers] field yourself, but
   /// it's much easier to use [isModifierPressed] if you just want to know if
   /// a modifier is pressed.
   /// {@endtemplate}
   static const int modifierCapsLock = 0x10000;

   /// This mask is used to check the [modifiers] field to test whether one of the
   /// SHIFT modifier keys is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierShift = 0x20000;

   /// This mask is used to check the [modifiers] field to test whether the left
   /// SHIFT modifier key is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierLeftShift = 0x02;

   /// This mask is used to check the [modifiers] field to test whether the right
   /// SHIFT modifier key is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierRightShift = 0x04;

   /// This mask is used to check the [modifiers] field to test whether one of the
   /// CTRL modifier keys is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierControl = 0x40000;

   /// This mask is used to check the [modifiers] field to test whether the left
   /// CTRL modifier key is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierLeftControl = 0x01;

   /// This mask is used to check the [modifiers] field to test whether the right
   /// CTRL modifier key is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierRightControl = 0x2000;

   /// This mask is used to check the [modifiers] field to test whether one of the
   /// ALT modifier keys is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierOption = 0x80000;

   /// This mask is used to check the [modifiers] field to test whether the left
   /// ALT modifier key is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierLeftOption = 0x20;

   /// This mask is used to check the [modifiers] field to test whether the right
   /// ALT modifier key is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierRightOption = 0x40;

   /// This mask is used to check the [modifiers] field to test whether one of the
   /// CMD modifier keys is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierCommand = 0x100000;

   /// This mask is used to check the [modifiers] field to test whether the left
   /// CMD modifier keys is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierLeftCommand = 0x08;

   /// This mask is used to check the [modifiers] field to test whether the right
   /// CMD modifier keys is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierRightCommand = 0x10;

   /// This mask is used to check the [modifiers] field to test whether any key in
   /// the numeric keypad is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierNumericPad = 0x200000;

   /// This mask is used to check the [modifiers] field to test whether the
   /// HELP modifier key is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierHelp = 0x400000;

   /// This mask is used to check the [modifiers] field to test whether one of the
   /// FUNCTION modifier keys is pressed.
   ///
   /// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
   static const int modifierFunction = 0x800000;

   /// Used to retrieve only the device-independent modifier flags, allowing
   /// applications to mask off the device-dependent modifier flags, including
   /// event coalescing information.
   static const int deviceIndependentMask = 0xffff0000;

   @override
   String toString() {
     return '${objectRuntimeType(this, 'RawKeyEventDataMacOs')}(keyLabel: $keyLabel, keyCode: $keyCode, characters: $characters,'
         ' unmodifiedCharacters: $charactersIgnoringModifiers, modifiers: $modifiers, '
         'modifiers down: $modifiersPressed)';
   }
 }
	// Copyright 2014 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'package:flutter/foundation.dart';

	import 'keyboard_key.dart';
	import 'keyboard_maps.dart';
	import 'raw_keyboard.dart';

	/// Platform-specific key event data for macOS.
	///
	/// This object contains information about key events obtained from macOS's
	/// `NSEvent` interface.
	///
	/// See also:
	///
	/// * [RawKeyboard], which uses this interface to expose key data.
	class RawKeyEventDataMacOs extends RawKeyEventData {
	/// Creates a key event data structure specific for macOS.
	///
	/// The [characters], [charactersIgnoringModifiers], and [modifiers], arguments
	/// must not be null.
	const RawKeyEventDataMacOs({
	this.characters = '',
	this.charactersIgnoringModifiers = '',
	this.keyCode = 0,
	this.modifiers = 0,
	}) : assert(characters != null),
	assert(charactersIgnoringModifiers != null),
	assert(keyCode != null),
	assert(modifiers != null);

	/// The Unicode characters associated with a key-up or key-down event.
	///
	/// See also:
	///
	/// * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1534183-characters?language=objc)
	final String characters;

	/// The characters generated by a key event as if no modifier key (except for
	/// Shift) applies.
	///
	/// See also:
	///
	/// * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1524605-charactersignoringmodifiers?language=objc)
	final String charactersIgnoringModifiers;

	/// The virtual key code for the keyboard key associated with a key event.
	///
	/// See also:
	///
	/// * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1534513-keycode?language=objc)
	final int keyCode;

	/// A mask of the current modifiers using the values in Modifier Flags.
	///
	/// See also:
	///
	/// * [Apple's NSEvent documentation](https://developer.apple.com/documentation/appkit/nsevent/1535211-modifierflags?language=objc)
	final int modifiers;

	@override
	String get keyLabel => charactersIgnoringModifiers.isEmpty ? null : charactersIgnoringModifiers;

	@override
	PhysicalKeyboardKey get physicalKey => kMacOsToPhysicalKey[keyCode] ?? PhysicalKeyboardKey.none;

	@override
	LogicalKeyboardKey get logicalKey {
	// Look to see if the keyCode is a printable number pad key, so that a
	// difference between regular keys (e.g. "=") and the number pad version
	// (e.g. the "=" on the number pad) can be determined.
	final LogicalKeyboardKey numPadKey = kMacOsNumPadMap[keyCode];
	if (numPadKey != null) {
	return numPadKey;
	}
	// If this key is printable, generate the LogicalKeyboardKey from its Unicode value.
	// Control keys such as ESC, CRTL, and SHIFT are not printable. HOME, DEL, arrow keys, and function
	// keys are considered modifier function keys, which generate invalid Unicode scalar values.
	if (keyLabel != null &&
	!LogicalKeyboardKey.isControlCharacter(keyLabel) &&
	!_isUnprintableKey(keyLabel)) {
	// Given that charactersIgnoringModifiers can contain a String of arbitrary length,
	// limit to a maximum of two Unicode scalar values. It is unlikely that a keyboard would produce a code point
	// bigger than 32 bits, but it is still worth defending against this case.
	assert(charactersIgnoringModifiers.length <= 2);
	int codeUnit = charactersIgnoringModifiers.codeUnitAt(0);
	if (charactersIgnoringModifiers.length == 2) {
	final int secondCode = charactersIgnoringModifiers.codeUnitAt(1);
	codeUnit = (codeUnit << 16) \| secondCode;
	}

	final int keyId = LogicalKeyboardKey.unicodePlane \| (codeUnit & LogicalKeyboardKey.valueMask);
	return LogicalKeyboardKey.findKeyByKeyId(keyId) ?? LogicalKeyboardKey(
	keyId,
	keyLabel: keyLabel,
	debugName: kReleaseMode ? null : 'Key ${keyLabel.toUpperCase()}',
	);
	}

	// Control keys like "backspace" and movement keys like arrow keys don't have a printable representation,
	// but are present on the physical keyboard. Since there is no logical keycode map for macOS
	// (macOS uses the keycode to reference physical keys), a LogicalKeyboardKey is created with
	// the physical key's HID usage and debugName. This avoids duplicating the physical
	// key map.
	if (physicalKey != PhysicalKeyboardKey.none) {
	final int keyId = physicalKey.usbHidUsage \| LogicalKeyboardKey.hidPlane;
	return LogicalKeyboardKey.findKeyByKeyId(keyId) ?? LogicalKeyboardKey(
	keyId,
	keyLabel: physicalKey.debugName,
	debugName: physicalKey.debugName,
	);
	}

	// This is a non-printable key that is unrecognized, so a new code is minted
	// with the autogenerated bit set.
	const int macOsKeyIdPlane = 0x00500000000;

	return LogicalKeyboardKey(
	macOsKeyIdPlane \| keyCode \| LogicalKeyboardKey.autogeneratedMask,
	debugName: kReleaseMode ? null : 'Unknown macOS key code $keyCode',
	);
	}

	bool _isLeftRightModifierPressed(KeyboardSide side, int anyMask, int leftMask, int rightMask) {
	if (modifiers & anyMask == 0) {
	return false;
	}
	// If only the "anyMask" bit is set, then we respond true for requests of
	// whether either left or right is pressed.
	// Handles the case where macOS supplies just the "either" modifier flag,
	// but not the left/right flag. (e.g. modifierShift but not
	// modifierLeftShift).
	final bool anyOnly = modifiers & (leftMask \| rightMask \| anyMask) == anyMask;
	switch (side) {
	case KeyboardSide.any:
	return true;
	case KeyboardSide.all:
	return modifiers & leftMask != 0 && modifiers & rightMask != 0 \|\| anyOnly;
	case KeyboardSide.left:
	return modifiers & leftMask != 0 \|\| anyOnly;
	case KeyboardSide.right:
	return modifiers & rightMask != 0 \|\| anyOnly;
	}
	return false;
	}

	@override
	bool isModifierPressed(ModifierKey key, {KeyboardSide side = KeyboardSide.any}) {
	final int independentModifier = modifiers & deviceIndependentMask;
	bool result;
	switch (key) {
	case ModifierKey.controlModifier:
	result = _isLeftRightModifierPressed(side, independentModifier & modifierControl, modifierLeftControl, modifierRightControl);
	break;
	case ModifierKey.shiftModifier:
	result = _isLeftRightModifierPressed(side, independentModifier & modifierShift, modifierLeftShift, modifierRightShift);
	break;
	case ModifierKey.altModifier:
	result = _isLeftRightModifierPressed(side, independentModifier & modifierOption, modifierLeftOption, modifierRightOption);
	break;
	case ModifierKey.metaModifier:
	result = _isLeftRightModifierPressed(side, independentModifier & modifierCommand, modifierLeftCommand, modifierRightCommand);
	break;
	case ModifierKey.capsLockModifier:
	result = independentModifier & modifierCapsLock != 0;
	break;
	// On macOS, the function modifier bit is set for any function key, like F1,
	// F2, etc., but the meaning of ModifierKey.modifierFunction in Flutter is
	// that of the Fn modifier key, so there's no good way to emulate that on
	// macOS.
	case ModifierKey.functionModifier:
	case ModifierKey.numLockModifier:
	case ModifierKey.symbolModifier:
	case ModifierKey.scrollLockModifier:
	// These modifier masks are not used in macOS keyboards.
	result = false;
	break;
	}
	assert(!result \|\| getModifierSide(key) != null, "$runtimeType thinks that a modifier is pressed, but can't figure out what side it's on.");
	return result;
	}

	@override
	KeyboardSide getModifierSide(ModifierKey key) {
	KeyboardSide findSide(int leftMask, int rightMask, int anyMask) {
	final int combinedMask = leftMask \| rightMask;
	final int combined = modifiers & combinedMask;
	if (combined == leftMask) {
	return KeyboardSide.left;
	} else if (combined == rightMask) {
	return KeyboardSide.right;
	} else if (combined == combinedMask \|\| modifiers & (combinedMask \| anyMask) == anyMask) {
	// Handles the case where macOS supplies just the "either" modifier
	// flag, but not the left/right flag. (e.g. modifierShift but not
	// modifierLeftShift).
	return KeyboardSide.all;
	}
	return null;
	}

	switch (key) {
	case ModifierKey.controlModifier:
	return findSide(modifierLeftControl, modifierRightControl, modifierControl);
	case ModifierKey.shiftModifier:
	return findSide(modifierLeftShift, modifierRightShift, modifierShift);
	case ModifierKey.altModifier:
	return findSide(modifierLeftOption, modifierRightOption, modifierOption);
	case ModifierKey.metaModifier:
	return findSide(modifierLeftCommand, modifierRightCommand, modifierCommand);
	case ModifierKey.capsLockModifier:
	case ModifierKey.numLockModifier:
	case ModifierKey.scrollLockModifier:
	case ModifierKey.functionModifier:
	case ModifierKey.symbolModifier:
	return KeyboardSide.all;
	}

	assert(false, 'Not handling $key type properly.');
	return null;
	}

	/// Returns true if the given label represents an unprintable key.
	///
	/// Examples of unprintable keys are "NSUpArrowFunctionKey = 0xF700"
	/// or "NSHomeFunctionKey = 0xF729".
	///
	/// See <https://developer.apple.com/documentation/appkit/1535851-function-key_unicodes?language=objc> for more
	/// information.
	///
	/// Used by [RawKeyEvent] subclasses to help construct IDs.
	static bool _isUnprintableKey(String label) {
	if (label.length > 1) {
	return false;
	}
	final int codeUnit = label.codeUnitAt(0);
	return codeUnit >= 0xF700 && codeUnit <= 0xF8FF;
	}

	// Modifier key masks. See Apple's NSEvent documentation
	// https://developer.apple.com/documentation/appkit/nseventmodifierflags?language=objc
	// https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-86/IOHIDSystem/IOKit/hidsystem/IOLLEvent.h.auto.html

	/// This mask is used to check the [modifiers] field to test whether the CAPS
	/// LOCK modifier key is on.
	///
	/// {@template flutter.services.rawKeyEventDataMacOs.modifiers}
	/// Use this value if you need to decode the [modifiers] field yourself, but
	/// it's much easier to use [isModifierPressed] if you just want to know if
	/// a modifier is pressed.
	/// {@endtemplate}
	static const int modifierCapsLock = 0x10000;

	/// This mask is used to check the [modifiers] field to test whether one of the
	/// SHIFT modifier keys is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierShift = 0x20000;

	/// This mask is used to check the [modifiers] field to test whether the left
	/// SHIFT modifier key is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierLeftShift = 0x02;

	/// This mask is used to check the [modifiers] field to test whether the right
	/// SHIFT modifier key is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierRightShift = 0x04;

	/// This mask is used to check the [modifiers] field to test whether one of the
	/// CTRL modifier keys is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierControl = 0x40000;

	/// This mask is used to check the [modifiers] field to test whether the left
	/// CTRL modifier key is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierLeftControl = 0x01;

	/// This mask is used to check the [modifiers] field to test whether the right
	/// CTRL modifier key is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierRightControl = 0x2000;

	/// This mask is used to check the [modifiers] field to test whether one of the
	/// ALT modifier keys is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierOption = 0x80000;

	/// This mask is used to check the [modifiers] field to test whether the left
	/// ALT modifier key is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierLeftOption = 0x20;

	/// This mask is used to check the [modifiers] field to test whether the right
	/// ALT modifier key is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierRightOption = 0x40;

	/// This mask is used to check the [modifiers] field to test whether one of the
	/// CMD modifier keys is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierCommand = 0x100000;

	/// This mask is used to check the [modifiers] field to test whether the left
	/// CMD modifier keys is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierLeftCommand = 0x08;

	/// This mask is used to check the [modifiers] field to test whether the right
	/// CMD modifier keys is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierRightCommand = 0x10;

	/// This mask is used to check the [modifiers] field to test whether any key in
	/// the numeric keypad is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierNumericPad = 0x200000;

	/// This mask is used to check the [modifiers] field to test whether the
	/// HELP modifier key is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierHelp = 0x400000;

	/// This mask is used to check the [modifiers] field to test whether one of the
	/// FUNCTION modifier keys is pressed.
	///
	/// {@macro flutter.services.rawKeyEventDataMacOs.modifiers}
	static const int modifierFunction = 0x800000;

	/// Used to retrieve only the device-independent modifier flags, allowing
	/// applications to mask off the device-dependent modifier flags, including
	/// event coalescing information.
	static const int deviceIndependentMask = 0xffff0000;

	@override
	String toString() {
	return '${objectRuntimeType(this, 'RawKeyEventDataMacOs')}(keyLabel: $keyLabel, keyCode: $keyCode, characters: $characters,'
	' unmodifiedCharacters: $charactersIgnoringModifiers, modifiers: $modifiers, '
	'modifiers down: $modifiersPressed)';
	}
	}