Add `Msg::as_{view,mut}()`

PiperOrigin-RevId: 597969809

rust/test/shared/accessors_test.rs

@@ -10,7 +10,7 @@
 use googletest::prelude::*;
 use matchers::{is_set, is_unset};
 use protobuf::Optional;
-use unittest_proto::proto2_unittest::{NestedTestAllTypes, TestAllTypes, TestAllTypes_};
+use unittest_proto::proto2_unittest::{TestAllTypes, TestAllTypes_};
 
 #[test]
 fn test_default_accessors() {
@@ -948,11 +948,11 @@ fn test_oneof_default_mut_accessors() {
 #[test]
 fn test_set_message_from_view() {
     use protobuf::MutProxy;
-    let mut m1 = NestedTestAllTypes::new();
 
-    let mut m2 = NestedTestAllTypes::new();
-    m2.payload_mut().optional_int32_mut().set(1);
+    let mut m1 = TestAllTypes::new();
+    m1.optional_int32_mut().set(1);
+    let mut m2 = TestAllTypes::new();
+    m2.as_mut().set(m1.as_view());
 
-    m1.payload_mut().set(m2.payload());
-    assert_that!(m1.payload().optional_int32(), eq(1));
+    assert_that!(m2.optional_int32(), eq(1i32));
 }

src/google/protobuf/compiler/rust/accessors/singular_message.cc

@@ -63,12 +63,12 @@ void SingularMessage::InMsgImpl(Context& ctx,
                  let submsg = unsafe {
                    $getter_mut_thunk$(self.inner.msg, self.inner.arena.raw())
                  };
-                 $msg_type$Mut::new($pbi$::Private, &mut self.inner, submsg)
+                 $msg_type$Mut::from_parent($pbi$::Private, &mut self.inner, submsg)
                  )rs");
              } else {
                ctx.Emit({}, R"rs(
                     let submsg = unsafe { $getter_mut_thunk$(self.inner.msg) };
-                    $msg_type$Mut::new($pbi$::Private, &mut self.inner, submsg)
+                    $msg_type$Mut::from_parent($pbi$::Private, &mut self.inner, submsg)
                   )rs");
              }
            }},

src/google/protobuf/compiler/rust/message.cc

@@ -497,7 +497,7 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
 
         impl<'a> $Msg$Mut<'a> {
           #[doc(hidden)]
-          pub fn new(_private: $pbi$::Private,
+          pub fn from_parent(_private: $pbi$::Private,
                      parent: &'a mut $pbr$::MessageInner,
                      msg: $pbi$::RawMessage)
             -> Self {
@@ -506,6 +506,10 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
                        $pbi$::Private, parent, msg)
             }
           }
+          #[doc(hidden)]
+          pub fn new(_private: $pbi$::Private, msg: &'a mut $pbr$::MessageInner) -> Self {
+            Self{ inner: $pbr$::MutatorMessageRef::new(_private, msg) }
+          }
           $accessor_fns_for_muts$
         }
 
@@ -544,6 +548,14 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
             $Msg::deserialize$
           }
 
+          pub fn as_view(&self) -> $Msg$View {
+            $Msg$View::new($pbi$::Private, self.inner.msg)
+          }
+
+          pub fn as_mut(&mut self) -> $Msg$Mut {
+            $Msg$Mut::new($pbi$::Private, &mut self.inner)
+          }
+
           $accessor_fns$
 
           $oneof_accessor_fns$