freezed

veilid-flutter/lib/veilid_encoding.dart

@@ -1,6 +1,9 @@
 import 'dart:convert';
 import 'dart:typed_data';
 
+import 'package:equatable/equatable.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+
 String base64UrlNoPadEncode(List<int> bytes) {
   var x = base64Url.encode(bytes);
   while (x.endsWith('=')) {
@@ -20,97 +23,91 @@ Uint8List base64UrlNoPadDecodeDynamic(dynamic source) {
   return base64.decode(source);
 }
 
-abstract class EncodedString {
-  late String contents;
-  EncodedString(String s) {
-    validate(s);
-    contents = s;
-  }
-  EncodedString.encode(List<int> b) {
-    var s = base64UrlNoPadEncode(b);
-    validate(s);
-    contents = s;
-  }
+@immutable
+abstract class EncodedString extends Equatable {
+  final String contents;
+  @override
+  List<Object> get props => [contents];
 
-  int encodedLength();
-  int decodedLength();
-  void validate(String s) {
-    var d = base64UrlNoPadDecode(s);
-    if (d.length != decodedLength()) {
-      throw Exception("length ${s.length} should be ${encodedLength()}");
-    }
-  }
+  const EncodedString(String s) : contents = s;
 
   Uint8List decode() {
     return base64UrlNoPadDecode(contents);
   }
 
   @override
-  String toString() {
-    return contents;
-  }
+  String toString() => contents;
 
   static T fromString<T extends EncodedString>(String s) {
     switch (T) {
       case FixedEncodedString32:
-        return FixedEncodedString32(s) as T;
+        return FixedEncodedString32.fromString(s) as T;
       case FixedEncodedString43:
-        return FixedEncodedString43(s) as T;
+        return FixedEncodedString43.fromString(s) as T;
       case FixedEncodedString86:
-        return FixedEncodedString86(s) as T;
+        return FixedEncodedString86.fromString(s) as T;
       default:
         throw UnimplementedError();
     }
   }
 }
 
+@immutable
 class FixedEncodedString32 extends EncodedString {
-  FixedEncodedString32(String s) : super(s);
-  @override
-  int encodedLength() {
+  const FixedEncodedString32._(String s) : super(s);
+  static int encodedLength() {
     return 32;
   }
 
-  @override
-  int decodedLength() {
+  static int decodedLength() {
     return 24;
   }
 
-  String toJson() {
-    return toString();
+  factory FixedEncodedString32.fromString(String s) {
+    var d = base64UrlNoPadDecode(s);
+    if (d.length != decodedLength()) {
+      throw Exception("length ${s.length} should be ${encodedLength()}");
+    }
+    return FixedEncodedString32._(s);
   }
 
-  FixedEncodedString32.fromJson(dynamic json) : this(json as String);
+  String toJson() => toString();
+  factory FixedEncodedString32.fromJson(dynamic json) =>
+      FixedEncodedString32.fromString(json as String);
 }
 
+@immutable
 class FixedEncodedString43 extends EncodedString {
-  FixedEncodedString43(String s) : super(s);
-  @override
-  int encodedLength() {
+  const FixedEncodedString43._(String s) : super(s);
+  static int encodedLength() {
     return 43;
   }
 
-  @override
-  int decodedLength() {
+  static int decodedLength() {
     return 32;
   }
 
-  String toJson() {
-    return toString();
+  factory FixedEncodedString43.fromString(String s) {
+    var d = base64UrlNoPadDecode(s);
+    if (d.length != decodedLength()) {
+      throw Exception("length ${s.length} should be ${encodedLength()}");
+    }
+    return FixedEncodedString43._(s);
   }
 
-  FixedEncodedString43.fromJson(dynamic json) : this(json as String);
+  String toJson() => toString();
+  factory FixedEncodedString43.fromJson(dynamic json) =>
+      FixedEncodedString43.fromString(json as String);
 }
 
+@immutable
 class FixedEncodedString86 extends EncodedString {
-  FixedEncodedString86(String s) : super(s);
-  @override
-  int encodedLength() {
+  const FixedEncodedString86._(String s) : super(s);
+  static int encodedLength() {
     return 86;
   }
 
-  @override
-  int decodedLength() {
+  static int decodedLength() {
     return 64;
   }
 
@@ -118,5 +115,14 @@ class FixedEncodedString86 extends EncodedString {
     return toString();
   }
 
-  FixedEncodedString86.fromJson(dynamic json) : this(json as String);
+  factory FixedEncodedString86.fromString(String s) {
+    var d = base64UrlNoPadDecode(s);
+    if (d.length != decodedLength()) {
+      throw Exception("length ${s.length} should be ${encodedLength()}");
+    }
+    return FixedEncodedString86._(s);
+  }
+
+  factory FixedEncodedString86.fromJson(dynamic json) =>
+      FixedEncodedString86.fromString(json as String);
 }