blob: ab9e3b0a95f0c1296fec1aca0ba03e232edd994c [file] [log] [blame]
// Copyright 2014 The Flutter Authors. 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:meta/meta.dart';
import 'base/context.dart';
import 'globals.dart' as globals;
/// The current [FeatureFlags] implementation.
///
/// If not injected, a default implementation is provided.
FeatureFlags get featureFlags => context.get<FeatureFlags>();
/// The interface used to determine if a particular [Feature] is enabled.
///
/// The rest of the tools code should use this class instead of looking up
/// features directly. To facilitate rolls to google3 and other clients, all
/// flags should be provided with a default implementation here. Clients that
/// use this class should extent instead of implement, so that new flags are
/// picked up automatically.
class FeatureFlags {
const FeatureFlags();
/// Whether flutter desktop for linux is enabled.
bool get isLinuxEnabled => isEnabled(flutterLinuxDesktopFeature);
/// Whether flutter desktop for macOS is enabled.
bool get isMacOSEnabled => isEnabled(flutterMacOSDesktopFeature);
/// Whether flutter web is enabled.
bool get isWebEnabled => isEnabled(flutterWebFeature);
/// Whether flutter desktop for Windows is enabled.
bool get isWindowsEnabled => isEnabled(flutterWindowsDesktopFeature);
/// Whether the Android embedding V2 is enabled.
bool get isAndroidEmbeddingV2Enabled => isEnabled(flutterAndroidEmbeddingV2Feature);
/// Whether the web incremental compiler is enabled.
bool get isWebIncrementalCompilerEnabled => isEnabled(flutterWebIncrementalCompiler);
/// Whether a particular feature is enabled for the current channel.
///
/// Prefer using one of the specific getters above instead of this API.
bool isEnabled(Feature feature) {
final String currentChannel = globals.flutterVersion.channel;
final FeatureChannelSetting featureSetting = feature.getSettingForChannel(currentChannel);
if (!featureSetting.available) {
return false;
}
bool isEnabled = featureSetting.enabledByDefault;
if (feature.configSetting != null) {
final bool configOverride = globals.config.getValue(feature.configSetting) as bool;
if (configOverride != null) {
isEnabled = configOverride;
}
}
if (feature.environmentOverride != null) {
if (globals.platform.environment[feature.environmentOverride]?.toLowerCase() == 'true') {
isEnabled = true;
}
}
return isEnabled;
}
}
/// All current Flutter feature flags.
const List<Feature> allFeatures = <Feature>[
flutterWebFeature,
flutterLinuxDesktopFeature,
flutterMacOSDesktopFeature,
flutterWindowsDesktopFeature,
flutterAndroidEmbeddingV2Feature,
flutterWebIncrementalCompiler,
];
/// The [Feature] for flutter web.
const Feature flutterWebFeature = Feature(
name: 'Flutter for web',
configSetting: 'enable-web',
environmentOverride: 'FLUTTER_WEB',
master: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
dev: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
beta: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
);
/// The [Feature] for macOS desktop.
const Feature flutterMacOSDesktopFeature = Feature(
name: 'Flutter for desktop on macOS',
configSetting: 'enable-macos-desktop',
environmentOverride: 'FLUTTER_MACOS',
master: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
dev: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
);
/// The [Feature] for Linux desktop.
const Feature flutterLinuxDesktopFeature = Feature(
name: 'Flutter for desktop on Linux',
configSetting: 'enable-linux-desktop',
environmentOverride: 'FLUTTER_LINUX',
master: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
);
/// The [Feature] for Windows desktop.
const Feature flutterWindowsDesktopFeature = Feature(
name: 'Flutter for desktop on Windows',
configSetting: 'enable-windows-desktop',
environmentOverride: 'FLUTTER_WINDOWS',
master: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
);
/// The [Feature] for generating projects using the new Android embedding.
const Feature flutterAndroidEmbeddingV2Feature = Feature(
name: 'flutter create generates projects using the Android embedding V2',
environmentOverride: 'ENABLE_ANDROID_EMBEDDING_V2',
configSetting: 'enable-android-embedding-v2',
beta: FeatureChannelSetting(
available: true,
enabledByDefault: true,
),
dev: FeatureChannelSetting(
available: true,
enabledByDefault: true,
),
master: FeatureChannelSetting(
available: true,
enabledByDefault: true,
),
stable: FeatureChannelSetting(
available: true,
enabledByDefault: true,
),
);
/// The [Feature] for using the incremental compiler instead of build runner.
const Feature flutterWebIncrementalCompiler = Feature(
name: 'Enable the incremental compiler for web builds',
configSetting: 'enable-web-incremental-compiler',
environmentOverride: 'WEB_INCREMENTAL_COMPILER',
master: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
dev: FeatureChannelSetting(
available: true,
enabledByDefault: false,
),
);
/// A [Feature] is a process for conditionally enabling tool features.
///
/// All settings are optional, and if not provided will generally default to
/// a "safe" value, such as being off.
///
/// The top level feature settings can be provided to apply to all channels.
/// Otherwise, more specific settings take precedence over higher level
/// settings.
class Feature {
/// Creates a [Feature].
const Feature({
@required this.name,
this.environmentOverride,
this.configSetting,
this.master = const FeatureChannelSetting(),
this.dev = const FeatureChannelSetting(),
this.beta = const FeatureChannelSetting(),
this.stable = const FeatureChannelSetting(),
});
/// The user visible name for this feature.
final String name;
/// The settings for the master branch and other unknown channels.
final FeatureChannelSetting master;
/// The settings for the dev branch.
final FeatureChannelSetting dev;
/// The settings for the beta branch.
final FeatureChannelSetting beta;
/// The settings for the stable branch.
final FeatureChannelSetting stable;
/// The name of an environment variable that can override the setting.
///
/// The environment variable needs to be set to the value 'true'. This is
/// only intended for usage by CI and not as an advertised method to enable
/// a feature.
///
/// If not provided, defaults to `null` meaning there is no override.
final String environmentOverride;
/// The name of a setting that can be used to enable this feature.
///
/// If not provided, defaults to `null` meaning there is no config setting.
final String configSetting;
/// A help message for the `flutter config` command, or null if unsupported.
String generateHelpMessage() {
if (configSetting == null) {
return null;
}
final StringBuffer buffer = StringBuffer('Enable or disable $name. '
'This setting will take effect on ');
final List<String> channels = <String>[
if (master.available) 'master',
if (dev.available) 'dev',
if (beta.available) 'beta',
if (stable.available) 'stable',
];
if (channels.length == 1) {
buffer.write('the ${channels.single} channel.');
} else if (channels.length == 2) {
buffer.write('the ${channels.join(' and ')} channels.');
} else {
final String prefix = (channels.toList()
..removeLast()).join(', ');
buffer.write('the $prefix, and ${channels.last} channels.');
}
return buffer.toString();
}
/// Retrieve the correct setting for the provided `channel`.
FeatureChannelSetting getSettingForChannel(String channel) {
switch (channel) {
case 'stable':
return stable;
case 'beta':
return beta;
case 'dev':
return dev;
case 'master':
default:
return master;
}
}
}
/// A description of the conditions to enable a feature for a particular channel.
class FeatureChannelSetting {
const FeatureChannelSetting({
this.available = false,
this.enabledByDefault = false,
});
/// Whether the feature is available on this channel.
///
/// If not provided, defaults to `false`. This implies that the feature
/// cannot be enabled even by the settings below.
final bool available;
/// Whether the feature is enabled by default.
///
/// If not provided, defaults to `false`.
final bool enabledByDefault;
}