Add buildSdkSummary() to analyzer API.

R=brianwilkerson@google.com

Bug: dart-lang/build#2745 (comment)
Change-Id: I144dd99be5e5a210e27f3b5b5b54951659479511
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/153384
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analyzer/CHANGELOG.md

@@ -1,3 +1,6 @@
+## 0.39.13-dev
+* Added 'dart/sdk/build_sdk_summary.dart' with `buildSdkSummary`.
+
 ## 0.39.12
 * Deprecated `canUseSummaries` in `DartSdkManager` constructor.
   Summaries are not supported this way for SDK.

pkg/analyzer/lib/dart/sdk/build_sdk_summary.dart

@@ -0,0 +1,192 @@
+// Copyright (c) 2020, 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:typed_data';
+
+import 'package:_fe_analyzer_shared/src/sdk/allowed_experiments.dart';
+import 'package:analyzer/dart/analysis/features.dart';
+import 'package:analyzer/dart/analysis/utilities.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/dart/analysis/experiments.dart';
+import 'package:analyzer/src/dart/analysis/session.dart';
+import 'package:analyzer/src/dart/ast/ast.dart';
+import 'package:analyzer/src/dart/sdk/sdk.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/summary/format.dart';
+import 'package:analyzer/src/summary/summarize_elements.dart';
+import 'package:analyzer/src/summary2/link.dart';
+import 'package:analyzer/src/summary2/linked_element_factory.dart';
+import 'package:analyzer/src/summary2/reference.dart';
+import 'package:meta/meta.dart';
+import 'package:yaml/yaml.dart';
+
+/// Build summary for SDK at the given [sdkPath].
+///
+/// If [embedderYamlPath] is provided, then libraries from this file are
+/// appended to the libraries of the specified SDK.
+Uint8List buildSdkSummary({
+  @required ResourceProvider resourceProvider,
+  @required String sdkPath,
+  String embedderYamlPath,
+}) {
+  var sdk = FolderBasedDartSdk(
+    resourceProvider,
+    resourceProvider.getFolder(sdkPath),
+  );
+  sdk.analysisOptions = AnalysisOptionsImpl();
+
+  // Append libraries from the embedder.
+  if (embedderYamlPath != null) {
+    var file = resourceProvider.getFile(embedderYamlPath);
+    var content = file.readAsStringSync();
+    var map = loadYaml(content) as YamlMap;
+    var embedderSdk = EmbedderSdk(resourceProvider, {file.parent: map});
+    for (var library in embedderSdk.sdkLibraries) {
+      var uriStr = library.shortName;
+      if (sdk.libraryMap.getLibrary(uriStr) == null) {
+        sdk.libraryMap.setLibrary(uriStr, library);
+      }
+    }
+  }
+
+  var librarySources = sdk.sdkLibraries.map((e) {
+    return sdk.mapDartUri(e.shortName);
+  }).toList();
+
+  return _Builder(
+    sdk.context,
+    sdk.allowedExperimentsJson,
+    librarySources,
+  ).build();
+}
+
+class _Builder {
+  final AnalysisContext context;
+  final String allowedExperimentsJson;
+  final Iterable<Source> librarySources;
+
+  final Set<String> libraryUris = <String>{};
+  final List<LinkInputLibrary> inputLibraries = [];
+
+  AllowedExperiments allowedExperiments;
+  final PackageBundleAssembler bundleAssembler = PackageBundleAssembler();
+
+  _Builder(
+    this.context,
+    this.allowedExperimentsJson,
+    this.librarySources,
+  ) {
+    allowedExperiments = _parseAllowedExperiments(allowedExperimentsJson);
+  }
+
+  /// Build the linked bundle and return its bytes.
+  Uint8List build() {
+    librarySources.forEach(_addLibrary);
+
+    var elementFactory = LinkedElementFactory(
+      context,
+      AnalysisSessionImpl(null),
+      Reference.root(),
+    );
+
+    var linkResult = link(elementFactory, inputLibraries);
+    bundleAssembler.setBundle2(linkResult.bundle);
+
+    var buffer = PackageBundleBuilder(
+      bundle2: linkResult.bundle,
+      sdk: PackageBundleSdkBuilder(
+        allowedExperimentsJson: allowedExperimentsJson,
+      ),
+    ).toBuffer();
+
+    return buffer is Uint8List ? buffer : Uint8List.fromList(buffer);
+  }
+
+  void _addLibrary(Source source) {
+    String uriStr = source.uri.toString();
+    if (!libraryUris.add(uriStr)) {
+      return;
+    }
+
+    var inputUnits = <LinkInputUnit>[];
+
+    CompilationUnit definingUnit = _parse(source);
+    inputUnits.add(
+      LinkInputUnit(null, source, false, definingUnit),
+    );
+
+    for (Directive directive in definingUnit.directives) {
+      if (directive is NamespaceDirective) {
+        String libUri = directive.uri.stringValue;
+        Source libSource = context.sourceFactory.resolveUri(source, libUri);
+        _addLibrary(libSource);
+      } else if (directive is PartDirective) {
+        String partUri = directive.uri.stringValue;
+        Source partSource = context.sourceFactory.resolveUri(source, partUri);
+        CompilationUnit partUnit = _parse(partSource);
+        inputUnits.add(
+          LinkInputUnit(partUri, partSource, false, partUnit),
+        );
+      }
+    }
+
+    inputLibraries.add(
+      LinkInputLibrary(source, inputUnits),
+    );
+  }
+
+  /// Return the [FeatureSet] for the given [uri], must be a `dart:` URI.
+  FeatureSet _featureSet(Uri uri) {
+    if (uri.isScheme('dart')) {
+      var pathSegments = uri.pathSegments;
+      if (pathSegments.isNotEmpty) {
+        var libraryName = pathSegments.first;
+        var experiments = allowedExperiments.forSdkLibrary(libraryName);
+        return FeatureSet.fromEnableFlags(experiments);
+      }
+    }
+    throw StateError('Expected a valid dart: URI: $uri');
+  }
+
+  CompilationUnit _parse(Source source) {
+    var result = parseString(
+      content: source.contents.data,
+      featureSet: _featureSet(source.uri),
+      throwIfDiagnostics: false,
+    );
+
+    if (result.errors.isNotEmpty) {
+      var errorsStr = result.errors.map((e) {
+        var location = result.lineInfo.getLocation(e.offset);
+        return '${source.fullName}:$location - ${e.message}';
+      }).join('\n');
+      throw StateError(
+        'Unexpected diagnostics:\n$errorsStr',
+      );
+    }
+
+    var unit = result.unit as CompilationUnitImpl;
+    unit.languageVersion = LibraryLanguageVersion(
+      package: ExperimentStatus.currentVersion,
+      override: null,
+    );
+
+    return result.unit;
+  }
+
+  static AllowedExperiments _parseAllowedExperiments(String content) {
+    if (content == null) {
+      return AllowedExperiments(
+        sdkDefaultExperiments: [],
+        sdkLibraryExperiments: {},
+        packageExperiments: {},
+      );
+    }
+
+    return parseAllowedExperiments(content);
+  }
+}