Add CopyDir

v2/internal/fs/fs.go

@@ -218,3 +218,62 @@ func DirIsEmpty(dir string) (bool, error) {
 	}
 	return false, err // Either not empty or error, suits both cases
 }
+
+// Credit: https://gist.github.com/r0l1/92462b38df26839a3ca324697c8cba04
+// CopyDir recursively copies a directory tree, attempting to preserve permissions.
+// Source directory must exist, destination directory must *not* exist.
+// Symlinks are ignored and skipped.
+func CopyDir(src string, dst string) (err error) {
+	src = filepath.Clean(src)
+	dst = filepath.Clean(dst)
+
+	si, err := os.Stat(src)
+	if err != nil {
+		return err
+	}
+	if !si.IsDir() {
+		return fmt.Errorf("source is not a directory")
+	}
+
+	_, err = os.Stat(dst)
+	if err != nil && !os.IsNotExist(err) {
+		return
+	}
+	if err == nil {
+		return fmt.Errorf("destination already exists")
+	}
+
+	err = os.MkdirAll(dst, si.Mode())
+	if err != nil {
+		return
+	}
+
+	entries, err := ioutil.ReadDir(src)
+	if err != nil {
+		return
+	}
+
+	for _, entry := range entries {
+		srcPath := filepath.Join(src, entry.Name())
+		dstPath := filepath.Join(dst, entry.Name())
+
+		if entry.IsDir() {
+			err = CopyDir(srcPath, dstPath)
+			if err != nil {
+				return
+			}
+		} else {
+			// Skip symlinks.
+			if entry.Mode()&os.ModeSymlink != 0 {
+				continue
+			}
+
+			err = CopyFile(srcPath, dstPath)
+			if err != nil {
+				return
+			}
+		}
+	}
+
+	return
+}