From 9057c742e36d827540481838c172b6bd542b8461 Mon Sep 17 00:00:00 2001
From: Zach Cheung <kuroro.zhang@gmail.com>
Date: Sat, 20 Jul 2024 19:39:07 +0800
Subject: [PATCH] check file hash before mv

---
 main.go  |  9 +++++++++
 utils.go | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/main.go b/main.go
index 152d62c..d90a3f9 100644
--- a/main.go
+++ b/main.go
@@ -131,6 +131,15 @@ func main() {
 		// use repo base as filename
 		name := filepath.Base(repo)
 		destPath := filepath.Join(installDir, name)
+		isSameFile, err := isIdenticalFile(fpath, destPath)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if isSameFile {
+			log.Printf("%s is identical, no need to install", destPath)
+			return
+		}
+
 		if err := addExecutePermission(fpath); err != nil {
 			log.Fatalf("Error adding execute permission: %v", err)
 		}
diff --git a/utils.go b/utils.go
index ac2698e..949517e 100644
--- a/utils.go
+++ b/utils.go
@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"archive/zip"
 	"compress/gzip"
+	"crypto/sha256"
 	"fmt"
 	"io"
 	"log"
@@ -49,6 +50,15 @@ func extractAndInstallExecutables(archivePath, destDir string) error {
 		}
 		defer outFile.Close()
 
+		isSameFile, err := isIdenticalFile(oldpath, newpath)
+		if err != nil {
+			return err
+		}
+		if isSameFile {
+			log.Printf("%s is identical, no need to install", newpath)
+			return nil
+		}
+
 		if err := outFile.Chmod(mode); err != nil {
 			return err
 		}
@@ -275,3 +285,34 @@ func boolToInt(b bool) int {
 	}
 	return 0
 }
+
+func isIdenticalFile(src, dst string) (bool, error) {
+	srcHash, err := calculateSHA256(src)
+	if err != nil {
+		return false, err
+	}
+	dstHash, err := calculateSHA256(dst)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil
+		}
+		return false, err
+	}
+
+	return string(srcHash) == string(dstHash), nil
+}
+
+func calculateSHA256(filePath string) ([]byte, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	hash := sha256.New()
+	if _, err := io.Copy(hash, file); err != nil {
+		return nil, err
+	}
+
+	return hash.Sum(nil), nil
+}