| // 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); |
| } |