blob: 30a39a3a4c52216d821c85df2162ced5533c23ca [file] [log] [blame]
// Copyright (c) 2016, 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:async" show Future, Stream;
import "dart:convert" show Encoding;
import "io_none.dart"
if (dart.library.html) "io_html.dart"
if ( "io_io.dart" as io;
import "package_loader.dart";
/// Resource loading strategy.
/// An abstraction of the functionality needed to load resources.
/// Implementations of this interface decide which URI schemes they support.
abstract class ResourceLoader {
/// A resource loader that can load as many of the following URI
/// schemes as are supported by the platform:
/// * file
/// * http
/// * https
/// * data
/// * package
/// For example, `file:` URIs are not supported in the browser.
/// Relative URI references are accepted - they are resolved against
/// [Uri.base] before being loaded.
/// This loader is automatically used by the `Resource` class
/// if no other loader is specified.
static ResourceLoader get defaultLoader =>
const PackageLoader(DefaultLoader());
/// Reads the file located by [uri] as a stream of bytes.
Stream<List<int>> openRead(Uri uri);
/// Reads the file located by [uri] as a list of bytes.
Future<List<int>> readAsBytes(Uri uri);
/// Reads the file located by [uri] as a [String].
/// The file bytes are decoded using [encoding], if provided.
/// If [encoding] is omitted, the default for the `file:` scheme is UTF-8.
/// For `http`, `https` and `data` URIs, the Content-Type header's charset
/// is used, if available and recognized by [Encoding.getByName],
/// otherwise it defaults to Latin-1 for `http` and `https`
/// and to ASCII for `data` URIs.
Future<String> readAsString(Uri uri, {Encoding encoding});
/// Default implementation of [ResourceLoader].
/// Uses the system's available loading functionality to implement the
/// loading functions.
/// Supports as many of `http:`, `https:`, `file:` and `data:` URIs as
/// possible.
class DefaultLoader implements ResourceLoader {
const DefaultLoader();
Stream<List<int>> openRead(Uri uri) => io.readAsStream(uri);
Future<List<int>> readAsBytes(Uri uri) => io.readAsBytes(uri);
Future<String> readAsString(Uri uri, {Encoding encoding}) =>
io.readAsString(uri, encoding);