refactor: using string extension

lib/screens/gitea_repo.dart

@@ -36,7 +36,7 @@ class GiteaRepoScreen extends StatelessWidget {
         ]);
         return Tuple2(
           GiteaRepository.fromJson(res[0]),
-          convertBase64ToString(res[1]['content']),
+          (res[1]['content'] as String)?.base64ToUtf8,
         );
       },
       bodyBuilder: (t, setState) {

lib/screens/object.dart

@@ -88,7 +88,7 @@ class ObjectScreen extends StatelessWidget {
           final v = GithubTreeItem.fromJson(data);
           return BlobView(
             path,
-            base64Text: v.content,
+            base64Text: v.content?.dropLineBreak,
             networkUrl: v.downloadUrl,
           );
         }

lib/screens/repository.dart

@@ -49,7 +49,7 @@ class RepositoryScreen extends StatelessWidget {
   Future<String> _fetchReadme(BuildContext context) async {
     final data = await Provider.of<AuthModel>(context)
         .getWithCredentials('/repos/$owner/$name/readme');
-    return convertBase64ToString(data['content']);
+    return (data['content'] as String)?.dropLineBreak?.base64ToUtf8;
   }
 
   Widget _buildLanguages(BuildContext context, GhRepoRepository repo) {

lib/utils/extensions.dart

@@ -1,13 +1,9 @@
+import 'dart:convert';
+
 extension MyString<T extends String> on String {
-  int get toInt {
-    return int.parse(this);
-  }
-
-  String get urlencode {
-    return Uri.encodeComponent(this);
-  }
-
-  String get urldecode {
-    return Uri.decodeComponent(this);
-  }
+  int get toInt => int.parse(this);
+  String get urlencode => Uri.encodeComponent(this);
+  String get urldecode => Uri.decodeComponent(this);
+  String get dropLineBreak => this.replaceAll('\n', '');
+  String get base64ToUtf8 => utf8.decode(base64.decode(this));
 }

lib/utils/utils.dart

@@ -189,12 +189,6 @@ class RouterScreen {
 
 final dateFormat = DateFormat.yMMMMd();
 
-String convertBase64ToString(String input) {
-  if (input == null) return null;
-  final bits = base64.decode(input.replaceAll('\n', ''));
-  return utf8.decode(bits);
-}
-
 int sortByKey<T>(T key, T a, T b) {
   if (a == key && b != key) return -1;
   if (a != key && b == key) return 1;

lib/widgets/blob_view.dart

@@ -14,11 +14,15 @@ import 'package:git_touch/utils/utils.dart';
 
 class BlobView extends StatelessWidget {
   final String name;
-  final String text;
+  // final String text;
   final String base64Text;
   final String networkUrl;
-  BlobView(this.name, {this.text, this.base64Text, this.networkUrl})
-      : assert(text == null || base64Text == null);
+  BlobView(
+    this.name, {
+    // this.text,
+    @required this.base64Text,
+    this.networkUrl,
+  });
 
   String get _extname {
     var dotext = p.extension(name);
@@ -27,7 +31,6 @@ class BlobView extends StatelessWidget {
   }
 
   String get _language => _extname.isEmpty ? 'plaintext' : _extname;
-  String get _text => text ?? utf8.decode(base64.decode(base64Text));
 
   @override
   Widget build(BuildContext context) {
@@ -55,13 +58,13 @@ class BlobView extends StatelessWidget {
       case 'markdown':
         return Padding(
           padding: CommonStyle.padding,
-          child: MarkdownView(_text), // TODO: basePath
+          child: MarkdownView(base64Text.base64ToUtf8), // TODO: basePath
         );
       default:
         return SingleChildScrollView(
           scrollDirection: Axis.horizontal,
           child: HighlightView(
-            _text,
+            base64Text.base64ToUtf8,
             language: _language,
             theme: themeMap[theme.brightness == Brightness.dark
                 ? codeProvider.themeDark