Isolate the part of AnalysisDriver that manages the AnalysisContext.

pkg/analyzer/lib/src/dart/analysis/library_context.dart

Index: pkg/analyzer/lib/src/dart/analysis/library_context.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/library_context.dart b/pkg/analyzer/lib/src/dart/analysis/library_context.dart
new file mode 100644
index 0000000000000000000000000000000000000000..aac7379f2a027ca30e32a9a2d53a4f945b7f03a3
--- /dev/null
+++ b/pkg/analyzer/lib/src/dart/analysis/library_context.dart
@@ -0,0 +1,234 @@
+// Copyright (c) 2017, 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 'package:analyzer/context/declared_variables.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/element/element.dart' show CompilationUnitElement;
+import 'package:analyzer/error/error.dart';
+import 'package:analyzer/src/context/context.dart';
+import 'package:analyzer/src/dart/analysis/byte_store.dart';
+import 'package:analyzer/src/dart/analysis/driver.dart';
+import 'package:analyzer/src/dart/analysis/file_state.dart';
+import 'package:analyzer/src/generated/engine.dart'
+    show AnalysisContext, AnalysisEngine, AnalysisOptions;
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/summary/format.dart';
+import 'package:analyzer/src/summary/idl.dart';
+import 'package:analyzer/src/summary/link.dart';
+import 'package:analyzer/src/summary/package_bundle_reader.dart';
+import 'package:analyzer/src/task/dart.dart' show COMPILATION_UNIT_ELEMENT;
+import 'package:analyzer/task/dart.dart' show LibrarySpecificUnit;
+
+/**
+ * Context information necessary to analyze one or more libraries within an
+ * [AnalysisDriver].
+ *
+ * Currently this is implemented as a wrapper around [AnalysisContext].
+ * TODO(paulberry): make a front end API that this can make use of instead.
+ */
+class LibraryContext {
+  /**
+   * The [AnalysisContext] which is used to do the analysis.
+   */
+  final AnalysisContext _analysisContext;
+
+  /**
+   * Create a [LibraryContext] which is prepared to analyze [library].
+   */
+  factory LibraryContext.forSingleLibrary(
+      FileState library,
+      PerformanceLog logger,
+      PackageBundle sdkBundle,
+      ByteStore byteStore,
+      AnalysisOptions options,
+      DeclaredVariables declaredVariables,
+      SourceFactory sourceFactory,
+      FileSystemState fsState) {
+    return logger.run('Create library context', () {
+      Map<String, FileState> libraries = <String, FileState>{};
+      SummaryDataStore store = new SummaryDataStore(const <String>[]);
+
+      if (sdkBundle != null) {
+        store.addBundle(null, sdkBundle);
+      }
+
+      void appendLibraryFiles(FileState library) {
+        if (!libraries.containsKey(library.uriStr)) {
+          // Serve 'dart:' URIs from the SDK bundle.
+          if (sdkBundle != null && library.uri.scheme == 'dart') {
+            return;
+          }
+
+          libraries[library.uriStr] = library;
+
+          // Append the defining unit.
+          store.addUnlinkedUnit(library.uriStr, library.unlinked);
+
+          // Append parts.
+          for (FileState part in library.partedFiles) {
+            store.addUnlinkedUnit(part.uriStr, part.unlinked);
+          }
+
+          // Append referenced libraries.
+          library.importedFiles.forEach(appendLibraryFiles);
+          library.exportedFiles.forEach(appendLibraryFiles);
+        }
+      }
+
+      logger.run('Append library files', () {
+        return appendLibraryFiles(library);
+      });
+
+      Set<String> libraryUrisToLink = new Set<String>();
+      logger.run('Load linked bundles', () {
+        for (FileState library in libraries.values) {
+          if (library.exists) {
+            String key = '${library.transitiveSignature}.linked';
+            List<int> bytes = byteStore.get(key);
+            if (bytes != null) {
+              LinkedLibrary linked = new LinkedLibrary.fromBuffer(bytes);
+              store.addLinkedLibrary(library.uriStr, linked);
+            } else {
+              libraryUrisToLink.add(library.uriStr);
+            }
+          }
+        }
+        int numOfLoaded = libraries.length - libraryUrisToLink.length;
+        logger.writeln('Loaded $numOfLoaded linked bundles.');
+      });
+
+      Map<String, LinkedLibraryBuilder> linkedLibraries = {};
+      logger.run('Link bundles', () {
+        linkedLibraries = link(libraryUrisToLink, (String uri) {
+          LinkedLibrary linkedLibrary = store.linkedMap[uri];
+          return linkedLibrary;
+        }, (String uri) {
+          UnlinkedUnit unlinkedUnit = store.unlinkedMap[uri];
+          return unlinkedUnit;
+        }, (_) => null, options.strongMode);
+        logger.writeln('Linked ${linkedLibraries.length} bundles.');
+      });
+
+      linkedLibraries.forEach((uri, linkedBuilder) {
+        FileState library = libraries[uri];
+        String key = '${library.transitiveSignature}.linked';
+        List<int> bytes = linkedBuilder.toBuffer();
+        LinkedLibrary linked = new LinkedLibrary.fromBuffer(bytes);
+        store.addLinkedLibrary(uri, linked);
+        byteStore.put(key, bytes);
+      });
+
+      var analysisContext = _createAnalysisContext(
+          options, declaredVariables, sourceFactory, fsState, store);
+
+      return new LibraryContext._(analysisContext);
+    });
+  }
+
+  LibraryContext._(this._analysisContext);
+
+  /**
+   * Computes a [CompilationUnitElement] for the given library/unit pair.
+   */
+  CompilationUnitElement computeUnitElement(
+      Source librarySource, Source unitSource) {
+    return _analysisContext.computeResult(
+        new LibrarySpecificUnit(librarySource, unitSource),
+        COMPILATION_UNIT_ELEMENT);
+  }
+
+  /**
+   * Cleans up any persistent resources used by this [LibraryContext].
+   *
+   * Should be called once the [LibraryContext] is no longer needed.
+   */
+  void dispose() {
+    _analysisContext.dispose();
+  }
+
+  /**
+   * Computes a resolved [CompilationUnit] and a list of [AnalysisError]s for
+   * the given library/unit pair.
+   */
+  ResolutionResult resolveUnit(Source librarySource, Source unitSource) {
+    CompilationUnit resolvedUnit =
+        _analysisContext.resolveCompilationUnit2(unitSource, librarySource);
+    List<AnalysisError> errors = _analysisContext.computeErrors(unitSource);
+    return new ResolutionResult(resolvedUnit, errors);
+  }
+
+  static AnalysisContext _createAnalysisContext(
+      AnalysisOptions _analysisOptions,
+      DeclaredVariables declaredVariables,
+      SourceFactory _sourceFactory,
+      FileSystemState _fsState,
+      SummaryDataStore store) {
+    AnalysisContextImpl analysisContext =
+        AnalysisEngine.instance.createAnalysisContext();
+    analysisContext.useSdkCachePartition = false;
+    analysisContext.analysisOptions = _analysisOptions;
+    analysisContext.declaredVariables.addAll(declaredVariables);
+    analysisContext.sourceFactory = _sourceFactory.clone();
+    analysisContext.contentCache = new _ContentCacheWrapper(_fsState);
+    analysisContext.resultProvider =
+        new InputPackagesResultProvider(analysisContext, store);
+    return analysisContext;
+  }
+}
+
+/**
+ * Container object holding the result of a call to
+ * [LibraryContext.resolveUnit].
+ */
+class ResolutionResult {
+  final CompilationUnit resolvedUnit;
+  final List<AnalysisError> errors;
+
+  ResolutionResult(this.resolvedUnit, this.errors);
+}
+
+/**
+ * [ContentCache] wrapper around [FileContentOverlay].
+ */
+class _ContentCacheWrapper implements ContentCache {
+  final FileSystemState fsState;
+
+  _ContentCacheWrapper(this.fsState);
+
+  @override
+  void accept(ContentCacheVisitor visitor) {
+    throw new UnimplementedError();
+  }
+
+  @override
+  String getContents(Source source) {
+    return _getFileForSource(source).content;
+  }
+
+  @override
+  bool getExists(Source source) {
+    if (source.isInSystemLibrary) {
+      return true;
+    }
+    return _getFileForSource(source).exists;
+  }
+
+  @override
+  int getModificationStamp(Source source) {
+    if (source.isInSystemLibrary) {
+      return 0;
+    }
+    return _getFileForSource(source).exists ? 0 : -1;
+  }
+
+  @override
+  String setContents(Source source, String contents) {
+    throw new UnimplementedError();
+  }
+
+  FileState _getFileForSource(Source source) {
+    String path = source.fullName;
+    return fsState.getFileForPath(path);
+  }
+}