Add "url-safe" encoding to base64 in dart:convert.

tests/lib/convert/base64_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:convert';
 import "dart:typed_data";
 import "package:expect/expect.dart";
 
 main() {
   for (var list in [[],
@@ skipping 13 matching lines @@
 
   // Decoder is lenienet with mixed styles.
   Expect.listEquals([0xfb, 0xff, 0xbf, 0x00], BASE64.decode("-_+/AA%3D="));
   Expect.listEquals([0xfb, 0xff, 0xbf, 0x00], BASE64.decode("-_+/AA=%3D"));
 }
 
 void testRoundtrip(list, name) {
   // Direct.
   String encodedNormal = BASE64.encode(list);
   String encodedPercent = encodedNormal.replaceAll("=", "%3D");
-  String uriEncoded = encodedNormal.replaceAll("+", "-").replaceAll("/", "_");
+  String uriEncoded = BASE64URL.encode(list);
+  String expectedUriEncoded =
+      encodedNormal.replaceAll("+", "-").replaceAll("/", "_");
+  Expect.equals(expectedUriEncoded, uriEncoded);
+
   List result = BASE64.decode(encodedNormal);
   Expect.listEquals(list, result, name);
   result = BASE64.decode(encodedPercent);
   Expect.listEquals(list, result, name);
+  result = BASE64.decode(uriEncoded);
+  Expect.listEquals(list, result, name);
 
   int increment = list.length ~/ 7 + 1;
   // Chunked.
   for (int i = 0; i < list.length; i += increment) {
     for (int j = i; j < list.length; j += increment) {
+      // Normal
       {
         // Using add/close
         var results;
         var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
         var encoder = BASE64.encoder.startChunkedConversion(sink);
         encoder.add(list.sublist(0, i));
         encoder.add(list.sublist(i, j));
         encoder.add(list.sublist(j, list.length));
         encoder.close();
         var name = "0-$i-$j-${list.length}: list";
         Expect.equals(encodedNormal, results.join(""), name);
       }
       {
         // Using addSlice
         var results;
         var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
         var encoder = BASE64.encoder.startChunkedConversion(sink);
         encoder.addSlice(list, 0, i, false);
         encoder.addSlice(list, i, j, false);
         encoder.addSlice(list, j, list.length, true);
         var name = "0-$i-$j-${list.length}: $list";
         Expect.equals(encodedNormal, results.join(""), name);
       }
+      // URI
+      {
+        // Using add/close
+        var results;
+        var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
+        var encoder = BASE64URL.encoder.startChunkedConversion(sink);
+        encoder.add(list.sublist(0, i));
+        encoder.add(list.sublist(i, j));
+        encoder.add(list.sublist(j, list.length));
+        encoder.close();
+        var name = "0-$i-$j-${list.length}: list";
+        Expect.equals(uriEncoded, results.join(""), name);
+      }
+      {
+        // Using addSlice
+        var results;
+        var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
+        var encoder = BASE64URL.encoder.startChunkedConversion(sink);
+        encoder.addSlice(list, 0, i, false);
+        encoder.addSlice(list, i, j, false);
+        encoder.addSlice(list, j, list.length, true);
+        var name = "0-$i-$j-${list.length}: $list";
+        Expect.equals(uriEncoded, results.join(""), name);
+      }
     }
   }
 
   for (var encoded in [encodedNormal, encodedPercent, uriEncoded]) {
     increment = encoded.length ~/ 7 + 1;
     for (int i = 0; i < encoded.length; i += increment) {
       for (int j = i; j < encoded.length; j += increment) {
         {
           // Using add/close
           var results;
@@ skipping 35 matching lines @@
       });
       var c = BASE64.decoder.startChunkedConversion(sink);
       for (String string in list) {
         c.add(string);
       }
       c.close();
     }, isFormatException, "chunk $list");
   }
   void badDecode(String string) {
     Expect.throws(() => BASE64.decode(string), isFormatException, string);
+    Expect.throws(() => BASE64URL.decode(string), isFormatException, string);
     badChunkDecode([string]);
     badChunkDecode(["", string]);
     badChunkDecode([string, ""]);
     badChunkDecode([string, "", ""]);
     badChunkDecode(["", string, ""]);
   }
 
   badDecode("A");
   badDecode("AA");
   badDecode("AAA");
@@ skipping 113 matching lines @@
       BASE64.decoder.startChunkedConversion(new TestSink<List<int>>());
   ByteConversionSink encodeSink =
       BASE64.encoder.startChunkedConversion(new TestSink<String>());
 }
 
 // Implementation of Sink<T> to test type constraints.
 class TestSink<T> implements Sink<T> {
   void add(T value) {}
   void close() {}
 }