Use BitField<> in core type masks

* All core types masks are now correctly marked as bitfields.
* The enum hacks in MouseButtonMask and many other types are gone. This ensures that binders to other languages non C++ can actually implement type safe bitmasks.
* Most bitmask operations replaced by functions in BitField<>
* Key is still a problem because its enum and mask at the same time. While it kind of works in C++, this most likely can't be implemented safely in other languages and will have to be changed at some point. Mostly left as-is.
* Documentation and API dump updated to reflect bitfields in core types.

2 files changed, 41 insertions, 7 deletions

diff --git a/core/variant/binder_common.h b/core/variant/binder_common.h
index 358b3df0c5..81ac5adba7 100644
--- a/core/variant/binder_common.h
+++ b/core/variant/binder_common.h
@@ -146,22 +146,53 @@ VARIANT_ENUM_CAST(Side);
 VARIANT_ENUM_CAST(ClockDirection);
 VARIANT_ENUM_CAST(Corner);
 VARIANT_ENUM_CAST(HatDir);
-VARIANT_ENUM_CAST(HatMask);
+VARIANT_BITFIELD_CAST(HatMask);
 VARIANT_ENUM_CAST(JoyAxis);
 VARIANT_ENUM_CAST(JoyButton);
-VARIANT_ENUM_CAST(Key);
-VARIANT_ENUM_CAST(KeyModifierMask);
+
 VARIANT_ENUM_CAST(MIDIMessage);
 VARIANT_ENUM_CAST(MouseButton);
+VARIANT_BITFIELD_CAST(MouseButtonMask);
 VARIANT_ENUM_CAST(Orientation);
 VARIANT_ENUM_CAST(HorizontalAlignment);
 VARIANT_ENUM_CAST(VerticalAlignment);
 VARIANT_ENUM_CAST(InlineAlignment);
 VARIANT_ENUM_CAST(PropertyHint);
-VARIANT_ENUM_CAST(PropertyUsageFlags);
+VARIANT_BITFIELD_CAST(PropertyUsageFlags);
 VARIANT_ENUM_CAST(Variant::Type);
 VARIANT_ENUM_CAST(Variant::Operator);
 
+// Key
+
+VARIANT_ENUM_CAST(Key);
+VARIANT_BITFIELD_CAST(KeyModifierMask);
+
+static inline Key &operator|=(Key &a, BitField<KeyModifierMask> b) {
+	a = static_cast<Key>(static_cast<int>(a) | static_cast<int>(b.operator int64_t()));
+	return a;
+}
+
+static inline Key &operator&=(Key &a, BitField<KeyModifierMask> b) {
+	a = static_cast<Key>(static_cast<int>(a) & static_cast<int>(b.operator int64_t()));
+	return a;
+}
+
+static inline Key operator|(Key a, BitField<KeyModifierMask> b) {
+	return (Key)((int)a | (int)b.operator int64_t());
+}
+
+static inline Key operator&(Key a, BitField<KeyModifierMask> b) {
+	return (Key)((int)a & (int)b.operator int64_t());
+}
+
+static inline Key operator+(BitField<KeyModifierMask> a, Key b) {
+	return (Key)((int)a.operator int64_t() + (int)b);
+}
+
+static inline Key operator|(BitField<KeyModifierMask> a, Key b) {
+	return (Key)((int)a.operator int64_t() | (int)b);
+}
+
 template <>
 struct VariantCaster<char32_t> {
 	static _FORCE_INLINE_ char32_t cast(const Variant &p_variant) {
diff --git a/core/variant/type_info.h b/core/variant/type_info.h
index d3b507ba4d..e89658d25b 100644
--- a/core/variant/type_info.h
+++ b/core/variant/type_info.h
@@ -287,11 +287,14 @@ class BitField {
 	int64_t value = 0;
 
 public:
-	_FORCE_INLINE_ void set_flag(T p_flag) { value |= p_flag; }
-	_FORCE_INLINE_ bool has_flag(T p_flag) const { return value & p_flag; }
-	_FORCE_INLINE_ void clear_flag(T p_flag) { return value &= ~p_flag; }
+	_FORCE_INLINE_ void set_flag(T p_flag) { value |= (int64_t)p_flag; }
+	_FORCE_INLINE_ bool has_flag(T p_flag) const { return value & (int64_t)p_flag; }
+	_FORCE_INLINE_ bool is_empty() const { return value == 0; }
+	_FORCE_INLINE_ void clear_flag(T p_flag) { value &= ~(int64_t)p_flag; }
+	_FORCE_INLINE_ void clear() { value = 0; }
 	_FORCE_INLINE_ BitField() = default;
 	_FORCE_INLINE_ BitField(int64_t p_value) { value = p_value; }
+	_FORCE_INLINE_ BitField(T p_value) { value = (int64_t)p_value; }
 	_FORCE_INLINE_ operator int64_t() const { return value; }
 	_FORCE_INLINE_ operator Variant() const { return value; }
 };