danrubel
b4611b9357
Change-Id: Iad76a6d0b91ff83fce3dbd963d0c341b3b62eeb9 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/102880 Reviewed-by: Paul Berry <paulberry@google.com> Commit-Queue: Dan Rubel <danrubel@google.com>
93 lines
3.6 KiB
Dart
93 lines
3.6 KiB
Dart
// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import 'package:analyzer/src/dart/analysis/experiments.dart';
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import 'package:meta/meta.dart';
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import 'package:pub_semver/pub_semver.dart';
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/// Information about a single language feature whose presence or absence
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/// depends on the supported Dart SDK version, and possibly on the presence of
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/// experimental flags.
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abstract class Feature {
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/// Feature information for the 2018 constant update.
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static const constant_update_2018 = ExperimentalFeatures.constant_update_2018;
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/// Feature information for non-nullability by default.
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static const non_nullable = ExperimentalFeatures.non_nullable;
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/// Feature information for control flow collections.
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static const control_flow_collections =
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ExperimentalFeatures.control_flow_collections;
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/// Feature information for extension methods.
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static const extension_methods = ExperimentalFeatures.extension_methods;
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/// Feature information for spread collections.
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static const spread_collections = ExperimentalFeatures.spread_collections;
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/// Feature information for set literals.
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static const set_literals = ExperimentalFeatures.set_literals;
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/// Feature information for the triple-shift operator.
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static const triple_shift = ExperimentalFeatures.triple_shift;
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/// If the feature may be enabled or disabled on the command line, the
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/// experimental flag that may be used to enable it. Otherwise `null`.
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///
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/// Should be `null` if [status] is `current` or `abandoned`.
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String get experimentalFlag;
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/// If [status] is not `future`, the first version of the Dart SDK in which
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/// the given feature was supported. Otherwise `null`.
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Version get firstSupportedVersion;
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/// The status of the feature.
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FeatureStatus get status;
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}
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/// An unordered collection of [Feature] objects.
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abstract class FeatureSet {
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/// Computes a set of features for use in a unit test. Computes the set of
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/// features enabled in [sdkVersion], plus any specified [additionalFeatures].
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///
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/// If [sdkVersion] is not supplied (or is `null`), then the current set of
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/// enabled features is used as the starting point.
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@visibleForTesting
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factory FeatureSet.forTesting(
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{String sdkVersion, List<Feature> additionalFeatures}) =
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// ignore: invalid_use_of_visible_for_testing_member
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ExperimentStatus.forTesting;
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/// Computes the set of features implied by the given set of experimental
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/// enable flags.
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factory FeatureSet.fromEnableFlags(List<String> flags) =
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ExperimentStatus.fromStrings;
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/// Queries whether the given [feature] is contained in this feature set.
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bool isEnabled(Feature feature);
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/// Computes a subset of this FeatureSet by removing any features that weren't
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/// available in the given Dart SDK version.
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FeatureSet restrictToVersion(Version version);
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}
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/// Information about the status of a language feature.
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enum FeatureStatus {
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/// The language feature has not yet shipped. It may not be used unless an
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/// experimental flag is used to enable it.
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future,
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/// The language feature has not yet shipped, but we are testing the effect of
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/// enabling it by default. It may be used in any library with an appopriate
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/// version constraint, unless an experimental flag is used to disable it.
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provisional,
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/// The language feature has been shipped. It may be used in any library with
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/// an appropriate version constraint.
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current,
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/// The language feature is no longer planned. It may not be used.
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abandoned,
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}
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