From bb9cc77858e7d487d48a2fad80de138e2011f570 Mon Sep 17 00:00:00 2001
From: Paul Capron <paul@fragara.com>
Date: Wed, 24 Oct 2018 15:08:51 +0200
Subject: [PATCH 1/2] =?UTF-8?q?Don=E2=80=99t=20wrap=20stdin=20in=20a=20Buf?=
 =?UTF-8?q?Reader=20when=20prompting?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

stdin() is already buffered.

stdin().read_line() calls stdin().lock() behind the hood (see
https://doc.rust-lang.org/src/std/io/stdio.rs.html#274)
Here we are reading user input, prompting them to confirm their action:
it seems useless to handle mutex locking/unlocking explicitely and
beforehand to avoid its overhead.

This commit is related to issue #1103.
---
 src/cp/cp.rs | 4 ++--
 src/ln/ln.rs | 4 ++--
 src/mv/mv.rs | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/cp/cp.rs b/src/cp/cp.rs
index de05619c4..ae04475b1 100644
--- a/src/cp/cp.rs
+++ b/src/cp/cp.rs
@@ -42,7 +42,7 @@ use clap::{App, Arg, ArgMatches};
 use quick_error::ResultExt;
 use std::collections::HashSet;
 use std::fs;
-use std::io::{stdin, stdout, BufRead, BufReader, Write};
+use std::io::{stdin, stdout, Write};
 use std::io;
 use std::path::{Path, PathBuf, StripPrefixError};
 use std::str::FromStr;
@@ -123,7 +123,7 @@ macro_rules! prompt_yes(
         print!(" [y/N]: ");
         crash_if_err!(1, stdout().flush());
         let mut s = String::new();
-        match BufReader::new(stdin()).read_line(&mut s) {
+        match stdin().read_line(&mut s) {
             Ok(_) => match s.char_indices().nth(0) {
                 Some((_, x)) => x == 'y' || x == 'Y',
                 _ => false
diff --git a/src/ln/ln.rs b/src/ln/ln.rs
index d182bd688..d6c89f50d 100644
--- a/src/ln/ln.rs
+++ b/src/ln/ln.rs
@@ -13,7 +13,7 @@
 extern crate uucore;
 
 use std::fs;
-use std::io::{stdin, BufRead, BufReader, Result};
+use std::io::{stdin, Result};
 #[cfg(any(unix, target_os = "redox"))]
 use std::os::unix::fs::symlink;
 #[cfg(windows)]
@@ -303,7 +303,7 @@ fn link(src: &PathBuf, dst: &PathBuf, settings: &Settings) -> Result<()> {
 
 fn read_yes() -> bool {
     let mut s = String::new();
-    match BufReader::new(stdin()).read_line(&mut s) {
+    match stdin().read_line(&mut s) {
         Ok(_) => match s.char_indices().nth(0) {
             Some((_, x)) => x == 'y' || x == 'Y',
             _ => false,
diff --git a/src/mv/mv.rs b/src/mv/mv.rs
index 1b1ee68db..19746c956 100644
--- a/src/mv/mv.rs
+++ b/src/mv/mv.rs
@@ -16,7 +16,7 @@ extern crate uucore;
 
 use std::fs;
 use std::env;
-use std::io::{stdin, BufRead, BufReader, Result};
+use std::io::{stdin, Result};
 use std::path::{Path, PathBuf};
 
 static NAME: &str = "mv";
@@ -374,7 +374,7 @@ fn rename(from: &PathBuf, to: &PathBuf, b: &Behaviour) -> Result<()> {
 
 fn read_yes() -> bool {
     let mut s = String::new();
-    match BufReader::new(stdin()).read_line(&mut s) {
+    match stdin().read_line(&mut s) {
         Ok(_) => match s.chars().nth(0) {
             Some(x) => x == 'y' || x == 'Y',
             _ => false,

From 324cbad7a38f6b6206dff3c7c35e0d9398137a11 Mon Sep 17 00:00:00 2001
From: Paul Capron <paul@fragara.com>
Date: Wed, 24 Oct 2018 15:21:05 +0200
Subject: [PATCH 2/2] =?UTF-8?q?factor:=20Don=E2=80=99t=20wrap=20stdin=20in?=
 =?UTF-8?q?=20BufReader=20&=20use=20lock()?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

stdin() is already buffered.

Locking upfront explicitely avoid the overhead of mutex locking/unlocking
everytime a new line is read. See https://stackoverflow.com/a/17546731
and https://www.reddit.com/r/rust/comments/3rj54u/how_can_i_read_char_by_char_from_stdin/cwpojn1/

The code cannot be simplified to “for line in stdin().lock().lines()”
until non-lexical lifetimes are implemented. The compiler complains at
the moment about a temporary value not living long enough/being dropped
while still borrowed. See https://github.com/rust-lang/rust/issues/33520

This commit is related to issue #1103.
---
 src/factor/factor.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/factor/factor.rs b/src/factor/factor.rs
index 97b92a4d3..2f5d5bb2f 100644
--- a/src/factor/factor.rs
+++ b/src/factor/factor.rs
@@ -23,7 +23,7 @@ use rand::distributions::{Distribution, Uniform};
 use rand::{SeedableRng, thread_rng};
 use rand::rngs::SmallRng;
 use std::cmp::{max, min};
-use std::io::{stdin, BufRead, BufReader};
+use std::io::{stdin, BufRead};
 use std::num::Wrapping;
 use std::mem::swap;
 
@@ -163,7 +163,8 @@ pub fn uumain(args: Vec<String>) -> i32 {
     let matches = new_coreopts!(SYNTAX, SUMMARY, LONG_HELP).parse(args);
 
     if matches.free.is_empty() {
-        for line in BufReader::new(stdin()).lines() {
+        let stdin = stdin();
+        for line in stdin.lock().lines() {
             for number in line.unwrap().split_whitespace() {
                 print_factors_str(number);
             }