Lazy cache 4 (#29785)

packages/flutter_tools/lib/src/base/build.dart

@@ -85,7 +85,6 @@ class AOTSnapshotter {
     if (fs.file('pubspec.yaml').existsSync()) {
       flutterProject = await FlutterProject.current();
     }
-    final FlutterEngine engine = FlutterEngine(cache);
     if (!_isValidAotPlatform(platform, buildMode)) {
       printError('${getNameForTargetPlatform(platform)} does not support AOT compilation.');
       return 1;
@@ -187,7 +186,7 @@ class AOTSnapshotter {
         'entryPoint': mainPath,
         'sharedLib': buildSharedLibrary.toString(),
         'extraGenSnapshotOptions': extraGenSnapshotOptions.join(' '),
-        'engineHash': engine.version,
+        'engineHash': Cache.instance.engineRevision,
         'buildersUsed': '${flutterProject != null ? flutterProject.hasBuilders : false}',
       },
       depfilePaths: <String>[],

packages/flutter_tools/lib/src/commands/analyze.dart

@@ -64,6 +64,11 @@ class AnalyzeCommand extends FlutterCommand {
   @override
   String get description => "Analyze the project's Dart code.";
 
+  @override
+  Set<DevelopmentArtifact> get requiredArtifacts => const <DevelopmentArtifact>{
+    DevelopmentArtifact.universal,
+  };
+
   @override
   bool get shouldRunPub {
     // If they're not analyzing the current project.

packages/flutter_tools/lib/src/commands/build_web.dart

@@ -8,7 +8,7 @@ import '../base/common.dart';
 import '../base/logger.dart';
 import '../build_info.dart';
 import '../globals.dart';
-import '../runner/flutter_command.dart' show FlutterCommandResult;
+import '../runner/flutter_command.dart' show DevelopmentArtifact, FlutterCommandResult;
 import '../web/compile.dart';
 import 'build.dart';
 
@@ -19,6 +19,12 @@ class BuildWebCommand extends BuildSubCommand {
     defaultBuildMode = BuildMode.release;
   }
 
+  @override
+  Set<DevelopmentArtifact> get requiredArtifacts => const <DevelopmentArtifact>{
+    DevelopmentArtifact.universal,
+    DevelopmentArtifact.web,
+  };
+
   @override
   final String name = 'web';
 

packages/flutter_tools/lib/src/commands/create.dart

@@ -245,7 +245,7 @@ class CreateCommand extends FlutterCommand {
       throwToolExit('Neither the --flutter-root command line flag nor the FLUTTER_ROOT environment '
         'variable was specified. Unable to find package:flutter.', exitCode: 2);
 
-    await Cache.instance.updateAll();
+    await Cache.instance.updateAll(<DevelopmentArtifact>{ DevelopmentArtifact.universal });
 
     final String flutterRoot = fs.path.absolute(Cache.flutterRoot);
 

packages/flutter_tools/lib/src/commands/ide_config.dart

@@ -223,7 +223,7 @@ class IdeConfigCommand extends FlutterCommand {
       throwToolExit('Currently, the only supported IDE is IntelliJ\n$usage', exitCode: 2);
     }
 
-    await Cache.instance.updateAll();
+    await Cache.instance.updateAll(<DevelopmentArtifact>{ DevelopmentArtifact.universal });
 
     if (argResults['update-templates']) {
       _handleTemplateUpdate();

packages/flutter_tools/lib/src/commands/precache.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import '../cache.dart';
 import '../globals.dart';
 import '../runner/flutter_command.dart';
 
@@ -11,6 +12,12 @@ class PrecacheCommand extends FlutterCommand {
   PrecacheCommand() {
     argParser.addFlag('all-platforms', abbr: 'a', negatable: false,
         help: 'Precache artifacts for all platforms.');
+    argParser.addFlag('android', negatable: true, defaultsTo: true,
+        help: 'Precache artifacts for Android development');
+    argParser.addFlag('ios', negatable: true, defaultsTo: true,
+        help: 'Precache artifacts for iOS developemnt');
+    argParser.addFlag('web', negatable: true, defaultsTo: false,
+        help: 'Precache artifacts for web development');
   }
 
   @override
@@ -24,14 +31,25 @@ class PrecacheCommand extends FlutterCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    if (argResults['all-platforms'])
+    if (argResults['all-platforms']) {
       cache.includeAllPlatforms = true;
-
-    if (cache.isUpToDate())
+    }
+    final Set<DevelopmentArtifact> requiredArtifacts = <DevelopmentArtifact>{ DevelopmentArtifact.universal };
+    if (argResults['android']) {
+      requiredArtifacts.add(DevelopmentArtifact.android);
+    }
+    if (argResults['ios']) {
+      requiredArtifacts.add(DevelopmentArtifact.iOS);
+    }
+    if (argResults['web']) {
+      requiredArtifacts.add(DevelopmentArtifact.web);
+    }
+
+    if (cache.isUpToDate(requiredArtifacts)) {
       printStatus('Already up-to-date.');
-    else
-      await cache.updateAll();
-
+    } else {
+      await cache.updateAll(requiredArtifacts);
+    }
     return null;
   }
 }

packages/flutter_tools/lib/src/compile.dart

@@ -232,7 +232,6 @@ class KernelCompiler {
     if (fs.file('pubspec.yaml').existsSync()) {
       flutterProject = await FlutterProject.current();
     }
-    final FlutterEngine engine = FlutterEngine(cache);
 
     // TODO(cbracken): eliminate pathFilter.
     // Currently the compiler emits buildbot paths for the core libs in the
@@ -246,7 +245,7 @@ class KernelCompiler {
           'entryPoint': mainPath,
           'trackWidgetCreation': trackWidgetCreation.toString(),
           'linkPlatformKernelIn': linkPlatformKernelIn.toString(),
-          'engineHash': engine.version,
+          'engineHash': Cache.instance.engineRevision,
           'buildersUsed': '${flutterProject != null ? flutterProject.hasBuilders : false}',
         },
         depfilePaths: <String>[depFilePath],

packages/flutter_tools/lib/src/doctor.dart

@@ -170,9 +170,7 @@ class Doctor {
   }
 
   Future<bool> checkRemoteArtifacts(String engineRevision) async {
-    final Cache cache = Cache();
-    final FlutterEngine engine = FlutterEngine(cache);
-    return await engine.areRemoteArtifactsAvailable(engineVersion: engineRevision);
+    return Cache.instance.areRemoteArtifactsAvailable(engineVersion: engineRevision);
   }
 
   /// Print information about the state of installed tooling.

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -19,6 +19,7 @@ import '../base/user_messages.dart';
 import '../base/utils.dart';
 import '../build_info.dart';
 import '../bundle.dart' as bundle;
+import '../cache.dart';
 import '../dart/package_map.dart';
 import '../dart/pub.dart';
 import '../device.dart';
@@ -28,6 +29,8 @@ import '../project.dart';
 import '../usage.dart';
 import 'flutter_command_runner.dart';
 
+export '../cache.dart' show DevelopmentArtifact;
+
 enum ExitStatus {
   success,
   warning,
@@ -530,8 +533,9 @@ abstract class FlutterCommand extends Command<void> {
 
     // Populate the cache. We call this before pub get below so that the sky_engine
     // package is available in the flutter cache for pub to find.
-    if (shouldUpdateCache)
-      await cache.updateAll();
+    if (shouldUpdateCache) {
+      await cache.updateAll(requiredArtifacts);
+    }
 
     if (shouldRunPub) {
       await pubGet(context: PubContext.getVerifyContext(name));
@@ -549,6 +553,16 @@ abstract class FlutterCommand extends Command<void> {
     return await runCommand();
   }
 
+  /// The set of development artifacts required for this command.
+  ///
+  /// Defaults to [DevelopmentArtifact.universal],
+  /// [DevelopmentArtifact.android], and [DevelopmentArtifact.iOS].
+  Set<DevelopmentArtifact> get requiredArtifacts => const <DevelopmentArtifact>{
+    DevelopmentArtifact.universal,
+    DevelopmentArtifact.iOS,
+    DevelopmentArtifact.android,
+  };
+
   /// Subclasses must implement this to execute the command.
   /// Optionally provide a [FlutterCommandResult] to send more details about the
   /// execution for analytics.

packages/flutter_tools/test/cache_test.dart

@@ -84,34 +84,34 @@ void main() {
     test('should not be up to date, if some cached artifact is not', () {
       final CachedArtifact artifact1 = MockCachedArtifact();
       final CachedArtifact artifact2 = MockCachedArtifact();
-      when(artifact1.isUpToDate()).thenReturn(true);
-      when(artifact2.isUpToDate()).thenReturn(false);
+      when(artifact1.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(true);
+      when(artifact2.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(false);
       final Cache cache = Cache(artifacts: <CachedArtifact>[artifact1, artifact2]);
-      expect(cache.isUpToDate(), isFalse);
+      expect(cache.isUpToDate(const <DevelopmentArtifact>{}), isFalse);
     });
     test('should be up to date, if all cached artifacts are', () {
       final CachedArtifact artifact1 = MockCachedArtifact();
       final CachedArtifact artifact2 = MockCachedArtifact();
-      when(artifact1.isUpToDate()).thenReturn(true);
-      when(artifact2.isUpToDate()).thenReturn(true);
+      when(artifact1.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(true);
+      when(artifact2.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(true);
       final Cache cache = Cache(artifacts: <CachedArtifact>[artifact1, artifact2]);
-      expect(cache.isUpToDate(), isTrue);
+      expect(cache.isUpToDate(const <DevelopmentArtifact>{}), isTrue);
     });
     test('should update cached artifacts which are not up to date', () async {
       final CachedArtifact artifact1 = MockCachedArtifact();
       final CachedArtifact artifact2 = MockCachedArtifact();
-      when(artifact1.isUpToDate()).thenReturn(true);
-      when(artifact2.isUpToDate()).thenReturn(false);
+      when(artifact1.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(true);
+      when(artifact2.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(false);
       final Cache cache = Cache(artifacts: <CachedArtifact>[artifact1, artifact2]);
-      await cache.updateAll();
+      await cache.updateAll(const <DevelopmentArtifact>{});
       verifyNever(artifact1.update());
       verify(artifact2.update());
     });
     testUsingContext('failed storage.googleapis.com download shows China warning', () async {
       final CachedArtifact artifact1 = MockCachedArtifact();
       final CachedArtifact artifact2 = MockCachedArtifact();
-      when(artifact1.isUpToDate()).thenReturn(false);
-      when(artifact2.isUpToDate()).thenReturn(false);
+      when(artifact1.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(false);
+      when(artifact2.isUpToDate(const <DevelopmentArtifact>{})).thenReturn(false);
       final MockInternetAddress address = MockInternetAddress();
       when(address.host).thenReturn('storage.googleapis.com');
       when(artifact1.update()).thenThrow(SocketException(
@@ -120,7 +120,7 @@ void main() {
       ));
       final Cache cache = Cache(artifacts: <CachedArtifact>[artifact1, artifact2]);
       try {
-        await cache.updateAll();
+        await cache.updateAll(const <DevelopmentArtifact>{});
         fail('Mock thrown exception expected');
       } catch (e) {
         verify(artifact1.update());

packages/flutter_tools/test/runner/flutter_command_test.dart

@@ -42,7 +42,7 @@ void main() {
     testUsingContext('honors shouldUpdateCache true', () async {
       final DummyFlutterCommand flutterCommand = DummyFlutterCommand(shouldUpdateCache: true);
       await flutterCommand.run();
-      verify(cache.updateAll()).called(1);
+      verify(cache.updateAll(any)).called(1);
     },
     overrides: <Type, Generator>{
       Cache: () => cache,