From 13b55800ae684e8e7faa524b926cc0c2e885847d Mon Sep 17 00:00:00 2001
From: Kisaragi Marine <kisaragi.effective@gmail.com>
Date: Sun, 3 Dec 2023 06:25:51 +0900
Subject: [PATCH] refactor: create base64 decoder only once

---
 src/main.rs | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 2d32842..b2887c4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,7 +12,6 @@ use std::process::exit;
 use std::sync::mpsc::RecvTimeoutError;
 use std::time::Duration;
 use base64::alphabet::STANDARD;
-use base64::Engine;
 use base64::engine::GeneralPurposeConfig;
 use clap::Parser;
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
@@ -181,8 +180,10 @@ fn main() {
         }
     });
 
+    // Base64エンジンを作るのはゼロコストではないので使いまわす
+    let base64_engine = base64::engine::GeneralPurpose::new(&STANDARD, GeneralPurposeConfig::new());
     // HTTPクライアントを作るのは少なくともゼロコストではないので使いまわす
-    assets.into_par_iter().for_each(|kv| process(kv, &args, &client, force, &sender));
+    assets.into_par_iter().for_each(|kv| process(kv, &args, &client, force, &sender, &base64_engine));
     // eprintln!("ended!!");
     please_exit.send(()).expect("error send");
     // eprintln!("signal sended, waiting join");
@@ -190,7 +191,14 @@ fn main() {
     // eprintln!("joined");
 }
 
-fn process((_, meta): (String, AssetMappingValue), args: &Args, client: &Client, force: bool, sender: &std::sync::mpsc::Sender<String>) {
+fn process<BE: base64::Engine>(
+    (_, meta): (String, AssetMappingValue),
+    args: &Args,
+    client: &Client,
+    force: bool,
+    sender: &std::sync::mpsc::Sender<String>,
+    base64: &BE
+) {
     let size = meta.size;
     let hash = &meta.hash;
     {
@@ -212,7 +220,7 @@ fn process((_, meta): (String, AssetMappingValue), args: &Args, client: &Client,
                         if let Ok(read_size) = br.read_to_end(&mut buf) {
                             if read_size == size {
                                 let actual = md5::compute(&buf).0;
-                                let base64_engine = base64::engine::GeneralPurpose::new(&STANDARD, GeneralPurposeConfig::new());
+                                let base64_engine = base64;
                                 if let Ok(decoded_azure_md5_header) = base64_engine.decode(azure_md5_header.as_bytes()) {
                                     if decoded_azure_md5_header == actual {
                                         sender.send(format!("{hash}: cached; skipping"));