fix: avoid error file name too long when writing a file (#4876)

weed/util/file_util.go

@@ -1,16 +1,20 @@
 package util
 
 import (
+	"bytes"
+	"crypto/sha256"
 	"errors"
+	"fmt"
+	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"os"
 	"os/user"
 	"path/filepath"
 	"strings"
 	"time"
-
-	"github.com/seaweedfs/seaweedfs/weed/glog"
 )
 
+const maxFilenameLength = 255
+
 func TestFolderWritable(folder string) (err error) {
 	fileInfo, err := os.Stat(folder)
 	if err != nil {
@@ -106,6 +110,19 @@ func FileNameBase(filename string) string {
 	return filename[:lastDotIndex]
 }
 
+func ToShortFileName(path string) string {
+	fileName := filepath.Base(path)
+	if fileNameBytes := []byte(fileName); len(fileNameBytes) > maxFilenameLength {
+		shaStr := fmt.Sprintf("%x", sha256.Sum256(fileNameBytes))
+		fileNameBase := FileNameBase(fileName)
+		fileExt := fileName[len(fileNameBase):]
+		fileNameBaseBates := bytes.ToValidUTF8([]byte(fileNameBase)[:maxFilenameLength-len([]byte(fileExt))-8], []byte{})
+		shortFileName := string(fileNameBaseBates) + shaStr[len(shaStr)-8:]
+		return filepath.Join(filepath.Dir(path), shortFileName) + fileExt
+	}
+	return path
+}
+
 // Copied from os.WriteFile(), adding file sync.
 // see https://github.com/golang/go/issues/20599
 func WriteFile(name string, data []byte, perm os.FileMode) error {