Move body generator for unit structs to its own module

Cut-paste
2026-04-22 10:17:58 +00:00 · 2025-09-20 00:10:10 +05:00
parent c4986f10b9
commit c4a07ed4e8
2 changed files with 53 additions and 47 deletions
@@ -0,0 +1,51 @@
+use crate::de::Parameters;
+use crate::fragment::Fragment;
+use crate::internals::attr;
+use crate::private;
+use quote::quote;
+
+/// Generates `Deserialize::deserialize` body for a `struct Unit;`
+pub fn deserialize_unit_struct(params: &Parameters, cattrs: &attr::Container) -> Fragment {
+    let this_type = &params.this_type;
+    let this_value = &params.this_value;
+    let type_name = cattrs.name().deserialize_name();
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = params.generics();
+    let delife = params.borrowed.de_lifetime();
+
+    let expecting = format!("unit struct {}", params.type_name());
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    quote_block! {
+        #[doc(hidden)]
+        struct __Visitor #de_impl_generics #where_clause {
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            #[inline]
+            fn visit_unit<__E>(self) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(#this_value)
+            }
+        }
+
+        _serde::Deserializer::deserialize_unit_struct(
+            __deserializer,
+            #type_name,
+            __Visitor {
+                marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
+                lifetime: _serde::#private::PhantomData,
+            },
+        )
+    }
+}