init

hdiff-any-game/checker.go

@@ -0,0 +1,138 @@
+package main
+
+import (
+	"crypto/md5"
+	"encoding/binary"
+	"encoding/hex"
+	"io"
+	"os"
+	"runtime"
+	"sync"
+
+	"github.com/schollz/progressbar/v3"
+)
+
+type DiffResult struct {
+	OnlyInOld []string
+	OnlyInNew []string
+	Changed   []string
+}
+
+func safePartialMD5(path string) (string, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	fi, err := f.Stat()
+	if err != nil {
+		return "", err
+	}
+	size := fi.Size()
+	modTime := fi.ModTime().UnixNano()
+
+	h := md5.New()
+
+	binary.Write(h, binary.LittleEndian, size)
+	binary.Write(h, binary.LittleEndian, modTime)
+	binary.Write(h, binary.LittleEndian, fi.Mode())
+
+	buf := make([]byte, 4096)
+
+	if size <= 16*1024 {
+		f.Seek(0, io.SeekStart)
+		io.Copy(h, f)
+		return hex.EncodeToString(h.Sum(nil)), nil
+	}
+
+	n, _ := f.Read(buf)
+	h.Write(buf[:n])
+
+	if size > 8192 {
+		mid := size / 2
+		f.Seek(mid-2048, io.SeekStart)
+		n, _ = f.Read(buf)
+		h.Write(buf[:n])
+	}
+
+	if size > 4096 {
+		f.Seek(-4096, io.SeekEnd)
+		n, _ = f.Read(buf)
+		h.Write(buf[:n])
+	}
+
+	return hex.EncodeToString(h.Sum(nil)), nil
+}
+
+func DiffFolders(oldPath, newPath string) (*DiffResult, error) {
+	oldFiles, err := collectFiles(oldPath)
+	if err != nil {
+		return nil, err
+	}
+	newFiles, err := collectFiles(newPath)
+	if err != nil {
+		return nil, err
+	}
+
+	result := &DiffResult{}
+	var mu sync.Mutex
+	var wg sync.WaitGroup
+
+	jobs := make(chan [3]string, 100)
+
+	total := 0
+	for rel := range oldFiles {
+		if _, ok := newFiles[rel]; ok {
+			total++
+		}
+	}
+
+	bar := progressbar.NewOptions(total,
+		progressbar.OptionSetDescription("🔍 Comparing files"),
+		progressbar.OptionSetWidth(30),
+		progressbar.OptionShowCount(),
+		progressbar.OptionSetPredictTime(true),
+		progressbar.OptionShowElapsedTimeOnFinish(),
+	)
+
+	workers := runtime.NumCPU() * 2
+
+	for i := 0; i < workers; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for job := range jobs {
+				rel, oldFile, newFile := job[0], job[1], job[2]
+				oldHash, _ := safePartialMD5(oldFile)
+				newHash, _ := safePartialMD5(newFile)
+				if oldHash != newHash {
+					mu.Lock()
+					result.Changed = append(result.Changed, rel)
+					mu.Unlock()
+				}
+				bar.Add(1)
+			}
+		}()
+	}
+
+	for rel, oldFile := range oldFiles {
+		if newFile, ok := newFiles[rel]; ok {
+			jobs <- [3]string{rel, oldFile, newFile}
+		} else {
+			result.OnlyInOld = append(result.OnlyInOld, rel)
+		}
+	}
+
+	for rel := range newFiles {
+		if _, ok := oldFiles[rel]; !ok {
+			result.OnlyInNew = append(result.OnlyInNew, rel)
+		}
+	}
+
+	close(jobs)
+	wg.Wait()
+	bar.Finish()
+
+	return result, nil
+}