Support using a mock SDK with the resolver in code-transformers, and switch

pkg/code_transformers/lib/src/dart_sdk.dart

Index: pkg/code_transformers/lib/src/dart_sdk.dart
diff --git a/pkg/code_transformers/lib/src/dart_sdk.dart b/pkg/code_transformers/lib/src/dart_sdk.dart
index 7b6f8e694c821af6bc6dd2802f3235bda9032c48..3a3357a335fe1c6c82e0a1d287fcd4e9b1447854 100644
--- a/pkg/code_transformers/lib/src/dart_sdk.dart
+++ b/pkg/code_transformers/lib/src/dart_sdk.dart
@@ -7,6 +7,11 @@ library code_transformers.src.dart_sdk;
 import 'dart:convert' as convert;
 import 'dart:io' show File, Platform, Process;
 import 'package:path/path.dart' as path;
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/java_io.dart';
+import 'package:analyzer/src/generated/sdk.dart';
+import 'package:analyzer/src/generated/sdk_io.dart' show DirectoryBasedDartSdk;
+import 'package:analyzer/src/generated/source.dart';
 
 
 /// Attempts to provide the current Dart SDK directory.
@@ -47,3 +52,174 @@ String get dartSdkDirectory {
 
   return null;
 }
+
+/// Sources that are annotated with a source uri, so it is easy to resolve how
+/// to support `Resolver.getImportUri`.
+abstract class UriAnnotatedSource extends Source {
+  Uri get uri;
+}
+
+/// Dart SDK which wraps all Dart sources as [UriAnnotatedSource] to ensure they
+/// are tracked with Uris.
+class DirectoryBasedDartSdkProxy extends DirectoryBasedDartSdk {
+  DirectoryBasedDartSdkProxy(String sdkDirectory)
+      : super(new JavaFile(sdkDirectory));
+
+  Source mapDartUri(String dartUri) =>
+      DartSourceProxy.wrap(super.mapDartUri(dartUri), Uri.parse(dartUri));
+}
+
+/// Dart SDK resolver which wraps all Dart sources to ensure they are tracked
+/// with URIs.
+class DartUriResolverProxy implements DartUriResolver {
+  final DartUriResolver _proxy;
+  DartUriResolverProxy(DartSdk sdk) :
+      _proxy = new DartUriResolver(sdk);
+
+  Source resolveAbsolute(Uri uri) =>
+    DartSourceProxy.wrap(_proxy.resolveAbsolute(uri), uri);
+
+  DartSdk get dartSdk => _proxy.dartSdk;
+
+  Source fromEncoding(UriKind kind, Uri uri) =>
+      throw new UnsupportedError('fromEncoding is not supported');
+
+  Uri restoreAbsolute(Source source) =>
+      throw new UnsupportedError('restoreAbsolute is not supported');
+}
+
+/// Source file for dart: sources which track the sources with dart: URIs.
+///
+/// This is primarily to support [Resolver.getImportUri] for Dart SDK (dart:)
+/// based libraries.
+class DartSourceProxy implements UriAnnotatedSource {
+
+  /// Absolute URI which this source can be imported from
+  final Uri uri;
+
+  /// Underlying source object.
+  final Source _proxy;
+
+  DartSourceProxy(this._proxy, this.uri);
+
+  /// Ensures that [source] is a DartSourceProxy.
+  static DartSourceProxy wrap(Source source, Uri uri) {
+    if (source == null || source is DartSourceProxy) return source;
+    return new DartSourceProxy(source, uri);
+  }
+
+  Source resolveRelative(Uri relativeUri) {
+    // Assume that the type can be accessed via this URI, since these
+    // should only be parts for dart core files.
+    return wrap(_proxy.resolveRelative(relativeUri), uri);
+  }
+
+  bool exists() => _proxy.exists();
+
+  bool operator ==(Object other) =>
+    (other is DartSourceProxy && _proxy == other._proxy);
+
+  int get hashCode => _proxy.hashCode;
+
+  TimestampedData<String> get contents => _proxy.contents;
+
+  String get encoding => _proxy.encoding;
+
+  String get fullName => _proxy.fullName;
+
+  int get modificationStamp => _proxy.modificationStamp;
+
+  String get shortName => _proxy.shortName;
+
+  UriKind get uriKind => _proxy.uriKind;
+
+  bool get isInSystemLibrary => _proxy.isInSystemLibrary;
+}
+
+
+/// Dart SDK which contains a mock implementation of the SDK libraries. May be
+/// used to speed up resultion when most of the core libraries is not needed.
+class MockDartSdk implements DartSdk {
+  final Map<Uri, _MockSdkSource> _sources = {};
+  final bool reportMissing;
+  final Map<String, SdkLibrary> _libs = {};
+  final String sdkVersion = '0';
+  List<String> get uris => _sources.keys.map((uri) => '$uri').toList();
+  final AnalysisContext context = new _SdkAnalysisContext();
+
+  MockDartSdk(Map<String, String> sources, {this.reportMissing}) {
+    sources.forEach((uriString, contents) {
+      var uri = Uri.parse(uriString);
+      _sources[uri] = new _MockSdkSource(uri, contents);
+      _libs[uriString] = new SdkLibraryImpl(uri.path)
+        ..setDart2JsLibrary()
+        ..setVmLibrary();
+    });
+  }
+
+  List<SdkLibrary> get sdkLibraries => _libs.values.toList();
+  SdkLibrary getSdkLibrary(String dartUri) => _libs[dartUri];
+  Source mapDartUri(String dartUri) => _getSource(Uri.parse(dartUri));
+
+  Source fromEncoding(UriKind kind, Uri uri) {
+    if (kind != UriKind.DART_URI) {
+      throw new UnsupportedError('expected dart: uri kind, got $kind.');
+    }
+    return _getSource(uri);
+  }
+
+  Source _getSource(Uri uri) {
+    var src = _sources[uri];
+    if (src == null) {
+      if (reportMissing) print('warning: missing mock for $uri.');
+      _sources[uri] = src =
+          new _MockSdkSource(uri, 'library dart.${uri.path};');
+    }
+    return src;
+  }
+}
+
+class _MockSdkSource implements UriAnnotatedSource {
+  /// Absolute URI which this source can be imported from.
+  final Uri uri;
+  final String _contents;
+
+  _MockSdkSource(this.uri, this._contents);
+
+  bool exists() => true;
+
+  int get hashCode => uri.hashCode;
+  
+  final int modificationStamp = 1;
+
+  TimestampedData<String> get contents =>
+      new TimestampedData(modificationStamp, _contents);
+
+  String get encoding => "${uriKind.encoding}$uri";
+
+  String get fullName => shortName;
+
+  String get shortName => uri.path;
+
+  UriKind get uriKind => UriKind.DART_URI;
+
+  bool get isInSystemLibrary => true;
+
+  Source resolveRelative(Uri relativeUri) =>
+      throw new UnsupportedError('not expecting relative urls in dart: mocks');
+}
+
+// TODO(sigmund): delete once we bump the dependency on analyzer.  We copied
+// this code from SdkAnalysisContext in 'analyzer/src/generated/engine.dart' to
+// prevent bumping the dependency on analyzer. We should remove this as soon as
+// we start depending on analyzer >= 0.15.5.
+class _SdkAnalysisContext extends AnalysisContextImpl {
+  @override
+  AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
+    if (factory == null) return super.createCacheFromSourceFactory(factory);
+    var sdk = factory.dartSdk;
+    if (sdk == null) throw "Missing a DartUriResolver in source factory";
+    return new AnalysisCache(
+        [AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
+  }
+}