From 2d19e67fc49db4b9ee5f56bb2156d2a7fe6e3405 Mon Sep 17 00:00:00 2001
From: Hiroyuki Ikezoe <hikezoe@mozilla.com>
Date: Sat, 14 Jan 2017 11:39:33 +0900
Subject: [PATCH] Bug 1330824 - Add IndexMut for nsStyleAutoArray. r=heycam

MozReview-Commit-ID: 9EU8g4SLoHp
---
 .../gecko_bindings/sugar/ns_style_auto_array.rs    | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/components/style/gecko_bindings/sugar/ns_style_auto_array.rs b/components/style/gecko_bindings/sugar/ns_style_auto_array.rs
index 9c41a0b6ec4..b20ee735631 100644
--- a/components/style/gecko_bindings/sugar/ns_style_auto_array.rs
+++ b/components/style/gecko_bindings/sugar/ns_style_auto_array.rs
@@ -7,7 +7,7 @@
 use gecko_bindings::bindings::Gecko_EnsureStyleAnimationArrayLength;
 use gecko_bindings::structs::nsStyleAutoArray;
 use std::iter::{once, Chain, Once, IntoIterator};
-use std::ops::Index;
+use std::ops::{Index, IndexMut};
 use std::slice::{Iter, IterMut};
 
 impl<T> Index<usize> for nsStyleAutoArray<T> {
@@ -23,6 +23,18 @@ impl<T> Index<usize> for nsStyleAutoArray<T> {
     }
 }
 
+impl<T> IndexMut<usize> for nsStyleAutoArray<T> {
+    fn index_mut(&mut self, index: usize) -> &mut T {
+        if index > self.len() {
+            panic!("out of range")
+        }
+        match index {
+            0 => &mut self.mFirstElement,
+            _ => &mut self.mOtherElements[index - 1],
+        }
+    }
+}
+
 impl<T> nsStyleAutoArray<T> {
     /// Mutably iterate over the array elements.
     pub fn iter_mut(&mut self) -> Chain<Once<&mut T>, IterMut<T>> {