From 69b9c23b3858dc87ceb6629b7640d5f579b8ed79 Mon Sep 17 00:00:00 2001 From: David Tolnay Date: Mon, 13 Aug 2018 17:09:13 -0700 Subject: [PATCH] Address review of RcVec --- src/libsyntax/util/rc_vec.rs | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/src/libsyntax/util/rc_vec.rs b/src/libsyntax/util/rc_vec.rs index b2785d7143d..99fbce1ad91 100644 --- a/src/libsyntax/util/rc_vec.rs +++ b/src/libsyntax/util/rc_vec.rs @@ -27,12 +27,7 @@ pub fn new(mut vec: Vec) -> Self { // to hold the initial elements. Callers that anticipate needing to // extend the vector may prefer RcVec::new_preserving_capacity. vec.shrink_to_fit(); - - RcVec { - offset: 0, - len: vec.len() as u32, - data: Lrc::new(vec), - } + Self::new_preserving_capacity(vec) } pub fn new_preserving_capacity(vec: Vec) -> Self { @@ -59,10 +54,10 @@ pub fn try_unwrap(self) -> Result, Self> { Ok(mut vec) => { // Drop any elements after our view of the data. vec.truncate(self.offset as usize + self.len as usize); - // Drop any elements before our view of the data. - if self.offset != 0 { - vec.drain(..self.offset as usize); - } + // Drop any elements before our view of the data. Do this after + // the `truncate` so that elements past the end of our view do + // not need to be copied around. + vec.drain(..self.offset as usize); Ok(vec) }