fix(build): snake_case service names (#190)

tonic-build/src/client.rs

@@ -1,11 +1,11 @@
-use crate::generate_doc_comments;
+use crate::{generate_doc_comments, naive_snake_case};
 use proc_macro2::TokenStream;
 use prost_build::{Method, Service};
 use quote::{format_ident, quote};
 
 pub(crate) fn generate(service: &Service, proto: &str) -> TokenStream {
     let service_ident = quote::format_ident!("{}Client", service.name);
-    let client_mod = quote::format_ident!("{}_client", service.name.to_ascii_lowercase());
+    let client_mod = quote::format_ident!("{}_client", naive_snake_case(&service.name));
     let methods = generate_methods(service, proto);
 
     let connect = generate_connect(&service_ident);

tonic-build/src/lib.rs

@@ -321,3 +321,31 @@ fn replace_wellknown(proto_path: &str, method: &Method) -> (TokenStream, TokenSt
 
     (request, response)
 }
+
+fn naive_snake_case(name: &str) -> String {
+    let mut s = String::new();
+    let mut it = name.chars().peekable();
+
+    while let Some(x) = it.next() {
+        s.push(x.to_ascii_lowercase());
+        if let Some(y) = it.peek() {
+            if y.is_uppercase() {
+                s.push('_');
+            }
+        }
+    }
+
+    s
+}
+
+#[test]
+fn test_snake_case() {
+    for case in &[
+        ("Service", "service"),
+        ("ThatHasALongName", "that_has_a_long_name"),
+        ("greeter", "greeter"),
+        ("ABCServiceX", "a_b_c_service_x"),
+    ] {
+        assert_eq!(naive_snake_case(case.0), case.1)
+    }
+}

tonic-build/src/server.rs

@@ -1,4 +1,4 @@
-use crate::{generate_doc_comment, generate_doc_comments};
+use crate::{generate_doc_comment, generate_doc_comments, naive_snake_case};
 use proc_macro2::{Span, TokenStream};
 use prost_build::{Method, Service};
 use quote::quote;
@@ -9,7 +9,7 @@ pub(crate) fn generate(service: &Service, proto_path: &str) -> TokenStream {
 
     let server_service = quote::format_ident!("{}Server", service.name);
     let server_trait = quote::format_ident!("{}", service.name);
-    let server_mod = quote::format_ident!("{}_server", service.name.to_ascii_lowercase());
+    let server_mod = quote::format_ident!("{}_server", naive_snake_case(&service.name));
     let generated_trait = generate_trait(service, proto_path, server_trait.clone());
     let service_doc = generate_doc_comments(&service.comments.leading);