fix(web/app/controllers): Fix condition for subfolder (#116)

See #49 and bd74ed3

Co-authored-by: Piggy <piggynl@outlook.com>

web/app/controllers/problem_data_manage.php

@@ -57,7 +57,7 @@ function echoFilePre($file_name) {
 				if ($zip->open($up_filename) === TRUE) {
 					$zip->extractTo("/var/uoj_data/upload/{$problem['id']}");
 					$zip->close();
-					exec("cd /var/uoj_data/upload/{$problem['id']}; if [ `find . -maxdepth 1 -type f`File = File ]; then for sub_dir in `find -maxdepth 1 -type d ! -name .`; do mv -f \$sub_dir/* . && rm -rf \$sub_dir; done; fi");
+					exec("cd /var/uoj_data/upload/{$problem['id']}; if [ -z "`find . -maxdepth 1 -type f`" ]; then for sub_dir in `find -maxdepth 1 -type d ! -name .`; do mv -f \$sub_dir/* . && rm -rf \$sub_dir; done; fi");
 					echo "<script>alert('上传成功！')</script>";
 				} else {
 					$errmsg = "解压失败！";