Field: map more methods

CHANGES.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 - Add a `bundled` feature for `gdal-sys` that allows to build and statically link a minimal bundled version of gdal during `cargo build`
+- Add methods ``alternative_name``, ``is_nullable``, ``is_unique``, ``default_value`` to ``Field``.
 
 ## 0.17.1
 

src/vector/defn.rs

@@ -99,17 +99,55 @@ impl<'a> Field<'a> {
         _string(rv)
     }
 
+    /// Get the alternative name (alias) of this field.
+    ///
+    /// This API is new as of GDAL 3.2.
+    #[cfg(any(major_ge_4, all(major_is_3, minor_ge_2)))]
+    pub fn alternative_name(&'a self) -> String {
+        let rv = unsafe { gdal_sys::OGR_Fld_GetAlternativeNameRef(self.c_field_defn) };
+        _string(rv)
+    }
+
+    /// Get the data type of this field.
     pub fn field_type(&'a self) -> OGRFieldType::Type {
         unsafe { gdal_sys::OGR_Fld_GetType(self.c_field_defn) }
     }
 
+    /// Get the formatting width for this field.
+    ///
+    /// Zero means no specified width.
     pub fn width(&'a self) -> i32 {
         unsafe { gdal_sys::OGR_Fld_GetWidth(self.c_field_defn) }
     }
 
+    /// Get the formatting precision for this field.
+    ///
+    /// This should normally be zero for fields of types other than Real.
     pub fn precision(&'a self) -> i32 {
         unsafe { gdal_sys::OGR_Fld_GetPrecision(self.c_field_defn) }
     }
+
+    /// Return whether this field can receive null values.
+    pub fn is_nullable(&'a self) -> bool {
+        unsafe { gdal_sys::OGR_Fld_IsNullable(self.c_field_defn) != 0 }
+    }
+
+    /// Return whether this field has a unique constraint.
+    ///
+    /// This API is new as of GDAL 3.2.
+    #[cfg(any(major_ge_4, all(major_is_3, minor_ge_2)))]
+    pub fn is_unique(&'a self) -> bool {
+        unsafe { gdal_sys::OGR_Fld_IsUnique(self.c_field_defn) != 0 }
+    }
+
+    /// Get default field value.
+    pub fn default_value(&'a self) -> Option<String> {
+        let rv = unsafe { gdal_sys::OGR_Fld_GetDefault(self.c_field_defn) };
+        if rv.is_null() {
+            return None;
+        }
+        Some(_string(rv))
+    }
 }
 
 pub struct GeomFieldIterator<'a> {

src/vector/layer.rs

@@ -1459,6 +1459,16 @@ mod tests {
         .map(|s| (s.0.to_string(), s.1))
         .collect::<Vec<_>>();
         assert_eq!(name_list, ok_names_types);
+
+        let field = layer.defn().fields().next().unwrap();
+        #[cfg(any(major_ge_4, all(major_is_3, minor_ge_2)))]
+        assert_eq!(field.alternative_name(), "");
+        assert_eq!(field.width(), 0);
+        assert_eq!(field.precision(), 0);
+        assert!(field.is_nullable());
+        #[cfg(any(major_ge_4, all(major_is_3, minor_ge_2)))]
+        assert!(!field.is_unique());
+        assert_eq!(field.default_value(), None);
     }
 
     #[test]