1 files changed, 52 insertions, 0 deletions
diff --git a/src/gen/field/singular.rs b/src/gen/field/singular.rs
new file mode 100644
index 0000000..3bd223f
--- /dev/null
+++ b/src/gen/field/singular.rs
@@ -0,0 +1,52 @@
+use crate::gen::field::elem::FieldElem;
+use crate::gen::field::option_kind::OptionKind;
+use crate::gen::file_and_mod::FileAndMod;
+use crate::gen::rust_types_values::RustType;
+use crate::Customize;
+
+#[derive(Clone, PartialEq, Eq, Copy)]
+pub enum SingularFieldFlag {
+    // proto2 or proto3 message
+    WithFlag {
+        required: bool,
+        option_kind: OptionKind,
+    },
+    // proto3
+    WithoutFlag,
+}
+
+impl SingularFieldFlag {
+    pub fn is_required(&self) -> bool {
+        match *self {
+            SingularFieldFlag::WithFlag { required, .. } => required,
+            SingularFieldFlag::WithoutFlag => false,
+        }
+    }
+}
+
+#[derive(Clone)]
+pub(crate) struct SingularField<'a> {
+    pub flag: SingularFieldFlag,
+    pub elem: FieldElem<'a>,
+}
+
+impl<'a> SingularField<'a> {
+    pub(crate) fn rust_storage_type(&self, reference: &FileAndMod) -> RustType {
+        match self.flag {
+            SingularFieldFlag::WithFlag { option_kind, .. } => {
+                option_kind.wrap_element(self.elem.rust_storage_elem_type(reference))
+            }
+            SingularFieldFlag::WithoutFlag => self.elem.rust_storage_elem_type(reference),
+        }
+    }
+
+    pub(crate) fn default_value(
+        &self,
+        customize: &Customize,
+        reference: &FileAndMod,
+        const_expr: bool,
+    ) -> String {
+        self.rust_storage_type(reference)
+            .default_value(customize, const_expr)
+    }
+}