From d15f9bd162b1f44c43df4c0dd74a29a6894e44ec Mon Sep 17 00:00:00 2001
From: Sam Rijs <srijs@airpost.net>
Date: Tue, 4 Jul 2017 13:36:42 +0200
Subject: [PATCH] Improve best-case performance for to_camel_case
---
src/lib.rs | 14 ++++++++------
src/macros/input_object.rs | 2 +-
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/src/lib.rs b/src/lib.rs
index daffddeb..1ad76b71 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -203,6 +203,8 @@ extern crate serde;
#[cfg(any(feature="iron-handlers", feature="rocket-handlers"))] extern crate serde_json;
+use std::borrow::Cow;
+
#[macro_use] mod macros;
mod ast;
pub mod parser;
@@ -296,22 +298,22 @@ impl<'a> From<Spanning<ParseError<'a>>> for GraphQLError<'a> {
}
#[doc(hidden)]
-pub fn to_camel_case(s: &str) -> String {
- let mut dest = String::new();
+pub fn to_camel_case<'a>(s: &'a str) -> Cow<'a, str> {
+ let mut dest = Cow::Borrowed(s);
for (i, part) in s.split('_').enumerate() {
if i > 0 && part.len() == 1 {
- dest.push_str(&part.to_uppercase());
+ dest += Cow::Owned(part.to_uppercase());
}
else if i > 0 && part.len() > 1 {
let first = part.chars().next().unwrap().to_uppercase().collect::<String>();
let second = &part[1..];
- dest.push_str(&first);
- dest.push_str(second);
+ dest += Cow::Owned(first);
+ dest += second;
}
else if i == 0 {
- dest.push_str(part);
+ dest = Cow::Borrowed(part);
}
}
diff --git a/src/macros/input_object.rs b/src/macros/input_object.rs
index 9bccac99..265750ee 100644
--- a/src/macros/input_object.rs
+++ b/src/macros/input_object.rs
@@ -64,7 +64,7 @@ macro_rules! graphql_input_object {
) => {
Some($name {
$( $field_name: {
- let n: String = $crate::to_camel_case(stringify!($field_name));
+ let n = $crate::to_camel_case(stringify!($field_name));
let v: Option<&&$crate::InputValue> = $var.get(&n[..]);
match v {