Reorganize barback's source files.

pkg/barback/lib/src/asset_id.dart

-// Copyright (c) 2013, 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.
-
-library barback.asset_id;
-
-import 'package:path/path.dart' as pathos;
-
-/// Identifies an asset within a package.
-class AssetId implements Comparable<AssetId> {
-  /// The name of the package containing this asset.
-  final String package;
-
-  /// The path to the asset relative to the root directory of [package].
-  ///
-  /// Source (i.e. read from disk) and generated (i.e. the output of a
-  /// [Transformer]) assets all have paths. Even intermediate assets that are
-  /// generated and then consumed by later transformations will still have
-  /// a path used to identify it.
-  ///
-  /// Asset paths always use forward slashes as path separators, regardless of
-  /// the host platform.
-  final String path;
-
-  /// Gets the file extension of the asset, if it has one, including the ".".
-  String get extension => pathos.extension(path);
-
-  /// Creates a new AssetId at [path] within [package].
-  ///
-  /// The [path] will be normalized: any backslashes will be replaced with
-  /// forward slashes (regardless of host OS) and "." and ".." will be removed
-  /// where possible.
-  AssetId(this.package, String path)
-      : path = _normalizePath(path);
-
-  /// Parses an [AssetId] string of the form "package|path/to/asset.txt".
-  ///
-  /// The [path] will be normalized: any backslashes will be replaced with
-  /// forward slashes (regardless of host OS) and "." and ".." will be removed
-  /// where possible.
-  factory AssetId.parse(String description) {
-    var parts = description.split("|");
-    if (parts.length != 2) {
-      throw new FormatException('Could not parse "$description".');
-    }
-
-    if (parts[0].isEmpty) {
-      throw new FormatException(
-          'Cannot have empty package name in "$description".');
-    }
-
-    if (parts[1].isEmpty) {
-      throw new FormatException(
-          'Cannot have empty path in "$description".');
-    }
-
-    return new AssetId(parts[0], parts[1]);
-  }
-
-  /// Deserializes an [AssetId] from [data], which must be the result of
-  /// calling [serialize] on an existing [AssetId].
-  ///
-  /// Note that this is intended for communicating ids across isolates and not
-  /// for persistent storage of asset identifiers. There is no guarantee of
-  /// backwards compatibility in serialization form across versions.
-  AssetId.deserialize(data)
-      : package = data[0],
-        path = data[1];
-
-  /// Returns `true` of [other] is an [AssetId] with the same package and path.
-  operator ==(other) =>
-      other is AssetId &&
-      package == other.package &&
-      path == other.path;
-
-  int get hashCode => package.hashCode ^ path.hashCode;
-
-  int compareTo(AssetId other) {
-    var packageComp = package.compareTo(other.package);
-    if (packageComp != 0) return packageComp;
-    return path.compareTo(other.path);
-  }
-
-  /// Returns a new [AssetId] with the same [package] as this one and with the
-  /// [path] extended to include [extension].
-  AssetId addExtension(String extension) =>
-      new AssetId(package, "$path$extension");
-
-  /// Returns a new [AssetId] with the same [package] and [path] as this one
-  /// but with file extension [newExtension].
-  AssetId changeExtension(String newExtension) =>
-      new AssetId(package, pathos.withoutExtension(path) + newExtension);
-
-  String toString() => "$package|$path";
-
-  /// Serializes this [AssetId] to an object that can be sent across isolates
-  /// and passed to [deserialize].
-  serialize() => [package, path];
-}
-
-String _normalizePath(String path) {
-  if (pathos.isAbsolute(path)) {
-    throw new ArgumentError('Asset paths must be relative, but got "$path".');
-  }
-
-  // Normalize path separators so that they are always "/" in the AssetID.
-  path = path.replaceAll(r"\", "/");
-
-  // Collapse "." and "..".
-  return pathos.posix.normalize(path);
-}