1 files changed, 62 insertions, 0 deletions
diff --git a/2.27.1/src/reflect/find_message_or_enum.rs b/2.27.1/src/reflect/find_message_or_enum.rs
new file mode 100644
index 0000000..7ee3915
--- /dev/null
+++ b/2.27.1/src/reflect/find_message_or_enum.rs
@@ -0,0 +1,62 @@
+use crate::descriptor::DescriptorProto;
+use crate::descriptor::EnumDescriptorProto;
+use crate::descriptor::FileDescriptorProto;
+
+pub(crate) enum MessageOrEnum<'a> {
+    Message(&'a DescriptorProto),
+    Enum(&'a EnumDescriptorProto),
+}
+
+impl<'a> MessageOrEnum<'a> {
+    fn from_two_options(
+        m: Option<&'a DescriptorProto>,
+        e: Option<&'a EnumDescriptorProto>,
+    ) -> MessageOrEnum<'a> {
+        match (m, e) {
+            (Some(_), Some(_)) => panic!("enum and message with the same name"),
+            (Some(m), None) => MessageOrEnum::Message(m),
+            (None, Some(e)) => MessageOrEnum::Enum(e),
+            (None, None) => panic!("not found"),
+        }
+    }
+}
+
+pub(crate) fn find_message_or_enum<'a>(
+    file: &'a FileDescriptorProto,
+    name_to_package: &str,
+) -> (String, MessageOrEnum<'a>) {
+    let mut path = name_to_package.split('.');
+    let first = path.next().unwrap();
+    let child_message = file
+        .get_message_type()
+        .iter()
+        .find(|m| m.get_name() == first);
+    let child_enum = file.get_enum_type().iter().find(|e| e.get_name() == first);
+
+    let mut package_to_name = String::new();
+    let mut me = MessageOrEnum::from_two_options(child_message, child_enum);
+
+    for name in path {
+        let message = match me {
+            MessageOrEnum::Message(m) => m,
+            MessageOrEnum::Enum(_) => panic!("enum has no children"),
+        };
+
+        if !package_to_name.is_empty() {
+            package_to_name.push_str(".");
+        }
+        package_to_name.push_str(message.get_name());
+
+        let child_message = message
+            .get_nested_type()
+            .iter()
+            .find(|m| m.get_name() == name);
+        let child_enum = message
+            .get_enum_type()
+            .iter()
+            .find(|e| e.get_name() == name);
+        me = MessageOrEnum::from_two_options(child_message, child_enum)
+    }
+
+    (package_to_name, me)
+}