Initial api

.gitignore

@@ -3,3 +3,5 @@ packages
 build/
 .pub/
 pubspec.lock
+
+generated

e2e_example/lib/copy_builder.dart

@@ -0,0 +1,31 @@
+// 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';
+
+import 'package:build/build.dart';
+
+// Makes copies of things!
+class CopyBuilder extends Builder {
+  @override
+  Future build(BuildStep buildStep) async {
+    var input = buildStep.input;
+    var copy = new Asset(_copiedAssetId(input.id), input.stringContents);
+    await buildStep.writeAsString(copy);
+  }
+
+  @override
+  List<AssetId> declareOutputs(AssetId inputId) => [_copiedAssetId(inputId)];
+
+  /// Only runs on the root package, and copies all *.txt files.
+  static List<Phase> buildPhases(PackageGraph graph) {
+    var phase = new Phase([
+      new CopyBuilder()
+    ], [
+      new InputSet(graph.root.name, filePatterns: ['**/*.txt'])
+    ]);
+    return [phase];
+  }
+}
+
+AssetId _copiedAssetId(AssetId inputId) => inputId.addExtension('.copy');

e2e_example/lib/transformer.dart

@@ -0,0 +1,12 @@
+// 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 'package:build/build.dart';
+
+import 'copy_builder.dart';
+
+class CopyTransformer extends BuilderTransformer {
+  final List<Builder> builders = [new CopyBuilder()];
+
+  CopyTransformer.asPlugin(_);
+}

e2e_example/pubspec.yaml

@@ -0,0 +1,13 @@
+name: e2e_example
+version: 0.1.0
+
+environment:
+  sdk: '>=1.9.1 <2.0.0'
+
+dependencies:
+  build:
+    path: ../
+
+transformers:
+- e2e_example:
+    $include: 'web/*.txt'

e2e_example/tool/build.dart

@@ -0,0 +1,36 @@
+// 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 'package:build/build.dart';
+
+import 'package:e2e_example/copy_builder.dart';
+
+main() async {
+  /// Builds a full package dependency graph for the current package.
+  var graph = new PackageGraph.forThisPackage();
+
+  /// Give [Builder]s access to a [PackageGraph] so they can choose which
+  /// packages to run on. This simplifies user code a lot, and helps to mitigate
+  /// the transitive deps issue.
+  var phases = CopyBuilder.buildPhases(graph);
+
+  var result = await build([phases]);
+
+  if (result.status == BuildStatus.Success) {
+    print('''
+Build Succeeded!
+
+Type: ${result.buildType}
+Outputs: ${result.outputs}''');
+  } else {
+    print('''
+Build Failed :(
+
+Type: ${result.buildType}
+Outputs: ${result.outputs}
+
+Exception: ${result.exception}
+Stack Trace:
+${result.stackTrace}''');
+  }
+}

e2e_example/web/foo.txt

@@ -0,0 +1 @@
+bar

lib/build.dart

@@ -1,4 +1,13 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// 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.
-library build;
+export 'src/asset/asset.dart';
+export 'src/asset/id.dart';
+export 'src/builder/build_step.dart';
+export 'src/builder/builder.dart';
+export 'src/generate/build_result.dart';
+export 'src/generate/build.dart';
+export 'src/generate/input_set.dart';
+export 'src/generate/phase.dart';
+export 'src/package_graph/package_graph.dart';
+export 'src/transformer/transformer.dart';

lib/src/asset/asset.dart

@@ -0,0 +1,17 @@
+// 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 'id.dart';
+
+/// A fully realized asset whose content is available synchronously.
+class Asset {
+  /// The id for this asset.
+  final AssetId id;
+
+  /// The content for this asset.
+  final String stringContents;
+
+  Asset(this.id, this.stringContents);
+
+  String toString() => 'Asset: $id';
+}

lib/src/asset/id.dart

@@ -0,0 +1,110 @@
+// 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 'package:path/path.dart' as pathos;
+
+/// Forked from the `barback` package.
+///
+/// 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);
+}

lib/src/asset/reader.dart

@@ -0,0 +1,11 @@
+// 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';
+import 'dart:convert';
+
+import 'id.dart';
+
+abstract class AssetReader {
+  Future<String> readAsString(AssetId id, {Encoding encoding: UTF8});
+}

lib/src/asset/writer.dart

@@ -0,0 +1,11 @@
+// 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';
+import 'dart:convert';
+
+import 'asset.dart';
+
+abstract class AssetWriter {
+  Future writeAsString(Asset asset, {Encoding encoding: UTF8});
+}

lib/src/builder/build_step.dart

@@ -0,0 +1,31 @@
+// 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';
+import 'dart:convert';
+
+import '../asset/asset.dart';
+import '../asset/id.dart';
+
+/// A single step in the build processes. This represents a single input and
+/// it also handles tracking of dependencies.
+class BuildStep {
+  /// The primary input for this build step.
+  final Asset input;
+
+  /// Reads an [Asset] by [id] as a [String] using [encoding].
+  ///
+  /// If [trackAsDependency] is true, then [id] will be marked as a dependency
+  /// of all [expectedOutputs].
+  Future<String> readAsString(AssetId id,
+      {Encoding encoding: UTF8, bool trackAsDependency: true});
+
+  /// Outputs an [Asset] using the current [AssetWriter], and adds [asset] to
+  /// [outputs].
+  void writeAsString(Asset asset, {Encoding encoding: UTF8});
+
+  /// Explicitly adds [id] as a dependency of all [expectedOutputs]. This is
+  /// not generally necessary unless forcing `trackAsDependency: false` when
+  /// calling [readAsString].
+  void addDependency(AssetId id);
+}

lib/src/builder/build_step_impl.dart

@@ -0,0 +1,78 @@
+// 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';
+import 'dart:collection';
+import 'dart:convert';
+
+import '../asset/asset.dart';
+import '../asset/id.dart';
+import '../asset/reader.dart';
+import '../asset/writer.dart';
+import 'build_step.dart';
+
+/// A single step in the build processes. This represents a single input and
+/// its expected and real outputs. It also handles tracking of dependencies.
+class BuildStepImpl implements BuildStep {
+  /// The primary input for this build step.
+  @override
+  final Asset input;
+
+  /// The list of all outputs which are expected/allowed to be output from this
+  /// step.
+  final List<AssetId> expectedOutputs;
+
+  /// The actual outputs of this build step.
+  UnmodifiableListView<Asset> get outputs => new UnmodifiableListView(_outputs);
+  final List<Asset> _outputs = [];
+
+  /// A future that completes once all outputs current are done writing.
+  Future get outputsCompleted => _outputsCompleted;
+  Future _outputsCompleted = new Future(() {});
+
+  /// The dependencies read in during this build step.
+  UnmodifiableListView<AssetId> get dependencies =>
+      new UnmodifiableListView(_dependencies);
+  final Set<AssetId> _dependencies = new Set<AssetId>();
+
+  /// Used internally for reading files.
+  final AssetReader _reader;
+
+  /// Used internally for writing files.
+  final AssetWriter _writer;
+
+  BuildStepImpl(
+      this.input, List<AssetId> expectedOutputs, this._reader, this._writer)
+      : expectedOutputs = new List.unmodifiable(expectedOutputs) {
+    /// The [input] is always a dependency.
+    _dependencies.add(input.id);
+  }
+
+  /// Reads an [Asset] by [id] as a [String] using [encoding].
+  ///
+  /// If [trackAsDependency] is true, then [id] will be marked as a dependency
+  /// of all [expectedOutputs].
+  @override
+  Future<String> readAsString(AssetId id,
+      {Encoding encoding: UTF8, bool trackAsDependency: true}) {
+    if (trackAsDependency) _dependencies.add(id);
+    return _reader.readAsString(id, encoding: encoding);
+  }
+
+  /// Outputs an [Asset] using the current [AssetWriter], and adds [asset] to
+  /// [outputs].
+  @override
+  void writeAsString(Asset asset, {Encoding encoding: UTF8}) {
+    _outputs.add(asset);
+    var done = _writer.writeAsString(asset, encoding: encoding);
+    _outputsCompleted = _outputsCompleted.then((_) => done);
+  }
+
+  /// Explicitly adds [id] as a dependency of all [expectedOutputs]. This is
+  /// not generally necessary unless forcing `trackAsDependency: false` when
+  /// calling [readAsString].
+  @override
+  void addDependency(AssetId id) {
+    _dependencies.add(id);
+  }
+}