From 8794e41728756e2a284ebcb9c666c6efcda62f8b Mon Sep 17 00:00:00 2001
From: Lzu Tao <taolzu@gmail.com>
Date: Thu, 6 Feb 2020 21:39:15 +0700
Subject: [PATCH] dev: Use bytecount for faster line count

---
 clippy_dev/Cargo.toml                 |  1 +
 clippy_dev/src/stderr_length_check.rs | 55 ++++++++++++---------------
 clippy_lints/src/missing_doc.rs       |  2 +-
 3 files changed, 27 insertions(+), 31 deletions(-)

diff --git a/clippy_dev/Cargo.toml b/clippy_dev/Cargo.toml
index b30ba61d2991..c8aa1e79f34c 100644
--- a/clippy_dev/Cargo.toml
+++ b/clippy_dev/Cargo.toml
@@ -5,6 +5,7 @@ authors = ["Philipp Hansch <dev@phansch.net>"]
 edition = "2018"
 
 [dependencies]
+bytecount = "0.6"
 clap = "2.33"
 itertools = "0.8"
 regex = "1"
diff --git a/clippy_dev/src/stderr_length_check.rs b/clippy_dev/src/stderr_length_check.rs
index e36feb3a2713..041ee6911377 100644
--- a/clippy_dev/src/stderr_length_check.rs
+++ b/clippy_dev/src/stderr_length_check.rs
@@ -1,54 +1,49 @@
 use std::ffi::OsStr;
-use walkdir::WalkDir;
+use std::fs;
+use std::path::{Path, PathBuf};
 
-use std::fs::File;
-use std::io::prelude::*;
+use walkdir::WalkDir;
 
 // The maximum length allowed for stderr files.
 //
 // We limit this because small files are easier to deal with than bigger files.
-const LIMIT: usize = 200;
+const LENGTH_LIMIT: usize = 200;
 
 pub fn check() {
-    let stderr_files = stderr_files();
-    let exceeding_files = exceeding_stderr_files(stderr_files).collect::<Vec<String>>();
+    let exceeding_files: Vec<_> = exceeding_stderr_files();
 
     if !exceeding_files.is_empty() {
-        eprintln!("Error: stderr files exceeding limit of {} lines:", LIMIT);
+        eprintln!("Error: stderr files exceeding limit of {} lines:", LENGTH_LIMIT);
         for path in exceeding_files {
-            println!("{}", path);
+            println!("{}", path.display());
         }
         std::process::exit(1);
     }
 }
 
-fn exceeding_stderr_files(files: impl Iterator<Item = walkdir::DirEntry>) -> impl Iterator<Item = String> {
-    files.filter_map(|file| {
-        let path = file.path().to_str().expect("Could not convert path to str").to_string();
-        let linecount = count_linenumbers(&path);
-        if linecount > LIMIT {
-            Some(path)
-        } else {
-            None
-        }
-    })
-}
-
-fn stderr_files() -> impl Iterator<Item = walkdir::DirEntry> {
+fn exceeding_stderr_files() -> Vec<PathBuf> {
     // We use `WalkDir` instead of `fs::read_dir` here in order to recurse into subdirectories.
     WalkDir::new("../tests/ui")
         .into_iter()
-        .filter_map(std::result::Result::ok)
-        .filter(|f| f.path().extension() == Some(OsStr::new("stderr")))
+        .filter_map(Result::ok)
+        .filter_map(|e| {
+            let p = e.into_path();
+            if p.extension() == Some(OsStr::new("stderr")) && count_linenumbers(&p) > LENGTH_LIMIT {
+                Some(p)
+            } else {
+                None
+            }
+        })
+        .collect()
 }
 
 #[must_use]
-fn count_linenumbers(filepath: &str) -> usize {
-    if let Ok(mut file) = File::open(filepath) {
-        let mut content = String::new();
-        file.read_to_string(&mut content).expect("Failed to read file?");
-        content.lines().count()
-    } else {
-        0
+fn count_linenumbers(filepath: &Path) -> usize {
+    match fs::read(filepath) {
+        Ok(content) => bytecount::count(&content, b'\n'),
+        Err(e) => {
+            eprintln!("Failed to read file: {}", e);
+            0
+        },
     }
 }
diff --git a/clippy_lints/src/missing_doc.rs b/clippy_lints/src/missing_doc.rs
index 5ebc8a4d6479..e502db59e66b 100644
--- a/clippy_lints/src/missing_doc.rs
+++ b/clippy_lints/src/missing_doc.rs
@@ -36,7 +36,7 @@ pub struct MissingDoc {
     doc_hidden_stack: Vec<bool>,
 }
 
-impl ::std::default::Default for MissingDoc {
+impl Default for MissingDoc {
     #[must_use]
     fn default() -> Self {
         Self::new()