Add Resource class. Currently unimplemented.

[email protected], [email protected]

Review URL: https://codereview.chromium.org//1181663002.

Author: lrhn

runtime/lib/core_patch.dart

@@ -205,3 +205,27 @@ class _SyncIterator implements Iterator {
     }
   }
 }
+
+patch class Resource {
+  /* patch */ const factory Resource(String uri) = _Resource;
+}
+
+class _Resource implements Resource {
+  final String _location;
+
+  const _Resource(String uri) : _location = uri;
+
+  Uri get uri => Uri.base.resolve(_location);
+
+  Stream<List<int>> openRead() {
+    throw new UnimplementedError("openRead");
+  }
+
+  Future<List<int>> readAsBytes() {
+    throw new UnimplementedError("readAsBytes");
+  }
+
+  Future<String> readAsString({Encoding encoding}) {
+    throw new UnimplementedError("readAsString");
+  }
+}

runtime/lib/internal_patch.dart

@@ -21,4 +21,4 @@ patch class CodeUnits {
 
 final bool is64Bit = _inquireIs64Bit();
 
-bool _inquireIs64Bit() native "Internal_inquireIs64Bit";
+bool _inquireIs64Bit() native "Internal_inquireIs64Bit";

sdk/lib/_internal/compiler/js_lib/core_patch.dart

@@ -510,3 +510,71 @@ class Uri {
     throw new UnsupportedError("'Uri.base' is not supported");
   }
 }
+
+@patch
+class Resource {
+  @patch
+  const factory Resource(String uri) = _Resource;
+}
+
+Uri _resolvePackageUri(Uri packageUri) {
+  assert(packageUri.scheme == "package");
+  if (packageUri.hasAuthority) {
+    throw new ArgumentError("Package-URI must not have a host: $packageUri");
+  }
+  var resolved = Uri.base.resolve("packages/${packageUri.path}");
+  return resolved;
+}
+
+class _Resource implements Resource {
+  final String _location;
+
+  const _Resource(String uri) : _location = uri;
+
+  Uri get uri => Uri.base.resolve(_location);
+
+  Stream<List<int>> openRead() {
+    Uri uri = this.uri;
+    if (uri.scheme == "package") {
+      uri = _resolvePackageUri(uri);
+    }
+    if (uri.scheme == "http" || uri.scheme == "https") {
+      return _readAsStream(uri);
+    }
+    throw new StateError("Unable to find resource, unknown scheme: $_location");
+  }
+
+  Future<List<int>> readAsBytes() {
+    Uri uri = this.uri;
+    if (uri.scheme == "package") {
+      uri = _resolvePackageUri(uri);
+    }
+    if (uri.scheme == "http" || uri.scheme == "https") {
+      return _readAsBytes(uri);
+    }
+    throw new StateError("Unable to find resource, unknown scheme: $_location");
+  }
+
+  Future<String> readAsString({Encoding encoding: UTF8}) {
+    Uri uri = this.uri;
+    if (uri.scheme == "package") {
+      uri = _resolvePackageUri(uri);
+    }
+    if (uri.scheme == "http" || uri.scheme == "https") {
+      return _readAsString(uri);
+    }
+    throw new StateError("Unable to find resource, unknown scheme: $_location");
+  }
+
+  Stream<List<int>> _readAsStream(Uri uri) {
+    throw new UnimplementedError("Streaming bytes via HTTP");
+  }
+
+  Future<List<int>> _readAsBytes(Uri uri) {
+    throw new UnimplementedError("Reading bytes via HTTP");
+  }
+
+  Future<String> _readAsString(Uri uri) {
+    throw new UnimplementedError("Reading string via HTTP");
+  }
+}

sdk/lib/core/core.dart

@@ -157,6 +157,7 @@ import "dart:_internal" hide Symbol;
 import "dart:_internal" as internal show Symbol;
 import "dart:convert" show UTF8, LATIN1, Encoding;
 import "dart:math" show Random;  // Used by List.shuffle.
+import "dart:async" show Stream, Future;  // Used by Resource.
 
 part "annotations.dart";
 part "bool.dart";
@@ -181,6 +182,7 @@ part "object.dart";
 part "pattern.dart";
 part "print.dart";
 part "regexp.dart";
+part "resource.dart";
 part "set.dart";
 part "sink.dart";
 part "stacktrace.dart";

sdk/lib/core/core_sources.gypi

@@ -29,6 +29,7 @@
     'pattern.dart',
     'print.dart',
     'regexp.dart',
+    'resource.dart',
     'set.dart',
     'sink.dart',
     'stacktrace.dart',

sdk/lib/core/resource.dart

@@ -0,0 +1,52 @@
+// Copyright (c) 2015, 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.
+
+part of dart.core;
+
+/**
+ * A resource that can be read into the program.
+ *
+ * A resource is data that can be located using a URI and read into
+ * the program at runtime.
+ * The URI may use the `package` scheme to read resources provided
+ * along with package sources.
+ */
+abstract class Resource {
+  /**
+   * Creates a resource object with the given [uri] as location.
+   *
+   * The `uri` is a string containing a valid URI.
+   * If the string is not a valid URI, using any of the functions on
+   * the resource object will fail.
+   *
+   * The URI may be relative, in which case it will be resolved
+   * against [Uri.base] before being used.
+   *
+   * The URI may use the `package` scheme, which is always supported.
+   * Other schemes may also be supported where possible.
+   */
+  external const factory Resource(String uri);
+
+  /**
+   * The location `uri` of this resource.
+   *
+   * This is a [Uri] of the `uri` parameter given to the constructor.
+   * If the parameter was not a valid URI, reading `uri` may fail.
+   */
+  Uri get uri;
+
+  /** Read the resource content as a stream of bytes. */
+  Stream<List<int>> openRead();
+
+  /** Read the resource content. */
+  Future<List<int>> readAsBytes();
+
+  /**
+   * Read the resource content as a string.
+   *
+   * The content is decoded into a string using an [Encoding].
+   * If no other encoding is provided, it defaults to UTF-8.
+   */
+  Future<String> readAsString({Encoding encoding});
+}