feat(qmetaobject): add "is" wrappers for special QJSValues

Author: Mikhail Zolotukhin

qmetaobject/src/qtdeclarative.rs

@@ -922,13 +922,29 @@ cpp_class!(
     pub unsafe struct QJSValue as "QJSValue"
 );
 
+/// Wrapper for [`QJSValue::SpecialValue`][qt]
+///
+/// [qt]: https://doc.qt.io/qt-5/qjsvalue.html#SpecialValue-enum
+#[repr(u32)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum QJSValueSpecialValue {
+    NullValue = 0,
+    UndefinedValue = 1,
+}
+
 impl QJSValue {
     pub fn is_bool(&self) -> bool {
         cpp!(unsafe [self as "const QJSValue *"] -> bool as "bool" {
             return self->isBool();
         })
     }
 
+    pub fn is_null(&self) -> bool {
+        cpp!(unsafe [self as "const QJSValue *"] -> bool as "bool" {
+            return self->isNull();
+        })
+    }
+
     pub fn is_number(&self) -> bool {
         cpp!(unsafe [self as "const QJSValue *"] -> bool as "bool" {
             return self->isNumber();
@@ -941,6 +957,12 @@ impl QJSValue {
         })
     }
 
+    pub fn is_undefined(&self) -> bool {
+        cpp!(unsafe [self as "const QJSValue *"] -> bool as "bool" {
+            return self->isUndefined();
+        })
+    }
+
     pub fn to_string(&self) -> QString {
         cpp!(unsafe [self as "const QJSValue *"] -> QString as "QString" {
             return self->toString();
@@ -1022,6 +1044,14 @@ impl From<bool> for QJSValue {
     }
 }
 
+impl From<QJSValueSpecialValue> for QJSValue {
+    fn from(a: QJSValueSpecialValue) -> QJSValue {
+        cpp!(unsafe [a as "QJSValue::SpecialValue"] -> QJSValue as "QJSValue" {
+            return QJSValue(a);
+        })
+    }
+}
+
 impl QMetaType for QJSValue {
     fn register(_name: Option<&CStr>) -> i32 {
         cpp!(unsafe [] -> i32 as "int" { return qMetaTypeId<QJSValue>(); })
@@ -1049,6 +1079,15 @@ mod qjsvalue_tests {
         assert!(!num_value.is_bool());
     }
 
+    #[test]
+    fn test_is_null() {
+        let null_value = QJSValue::from(QJSValueSpecialValue::NullValue);
+        let num_value = QJSValue::from(42);
+
+        assert!(null_value.is_null());
+        assert!(!num_value.is_null());
+    }
+
     #[test]
     fn test_is_number() {
         let string_value = QJSValue::from(QString::from("Konqui"));
@@ -1067,6 +1106,15 @@ mod qjsvalue_tests {
         assert!(!num_value.is_string());
     }
 
+    #[test]
+    fn test_is_undefined() {
+        let undefined_value = QJSValue::from(QJSValueSpecialValue::UndefinedValue);
+        let num_value = QJSValue::from(42);
+
+        assert!(undefined_value.is_undefined());
+        assert!(!num_value.is_undefined());
+    }
+
     #[test]
     fn test_qvariantlist_from_iter() {
         let v = vec![1u32, 2u32, 3u32];