Incremental migration of message.cc to Emit

PiperOrigin-RevId: 532287642

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

@@ -3685,28 +3685,24 @@ void MessageGenerator::GenerateSerializeOneExtensionRange(io::Printer* p,
 
 void MessageGenerator::GenerateSerializeWithCachedSizesToArray(io::Printer* p) {
   if (HasSimpleBaseClass(descriptor_, options_)) return;
-  Formatter format(p);
   if (descriptor_->options().message_set_wire_format()) {
     // Special-case MessageSet.
-    format(
+    p->Emit(R"cc(
-        "$uint8$* $classname$::_InternalSerialize(\n"
+      $uint8$* $classname$::_InternalSerialize(
-        "    $uint8$* target, ::$proto_ns$::io::EpsCopyOutputStream* stream) "
+          $uint8$* target,
-        "const {\n"
+          ::$proto_ns$::io::EpsCopyOutputStream* stream) const {
-        "$annotate_serialize$"
+        $annotate_serialize$ target =
-        "  target = $extensions$."
+            $extensions$.InternalSerializeMessageSetWithCachedSizesToArray(
-        "InternalSerializeMessageSetWithCachedSizesToArray(\n"  //
+                internal_default_instance(), target, stream);
-        "internal_default_instance(), target, stream);\n");
+        target = ::_pbi::InternalSerializeUnknownMessageSetItemsToArray(
-
+            $unknown_fields$, target, stream);
-    format(
+        return target;
-        "  target = ::_pbi::"
+      }
-        "InternalSerializeUnknownMessageSetItemsToArray(\n"
+    )cc");
-        "               $unknown_fields$, target, stream);\n");
-    format(
-        "  return target;\n"
-        "}\n");
     return;
   }
 
+  Formatter format(p);
   format(
       "$uint8$* $classname$::_InternalSerialize(\n"
       "    $uint8$* target, ::$proto_ns$::io::EpsCopyOutputStream* stream) "