Remove PubSummaryManager.

pkg/analyzer/lib/src/summary/pub_summary.dart

Index: pkg/analyzer/lib/src/summary/pub_summary.dart
diff --git a/pkg/analyzer/lib/src/summary/pub_summary.dart b/pkg/analyzer/lib/src/summary/pub_summary.dart
deleted file mode 100644
index 821b4fc25d3fbbe0ef2ab7e57bc8698747b80f35..0000000000000000000000000000000000000000
--- a/pkg/analyzer/lib/src/summary/pub_summary.dart
+++ /dev/null
@@ -1,835 +0,0 @@
-// Copyright (c) 2016, 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:async';
-import 'dart:collection';
-import 'dart:core';
-
-import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/ast/token.dart';
-import 'package:analyzer/error/listener.dart';
-import 'package:analyzer/file_system/file_system.dart';
-import 'package:analyzer/src/dart/scanner/reader.dart';
-import 'package:analyzer/src/dart/scanner/scanner.dart';
-import 'package:analyzer/src/generated/engine.dart';
-import 'package:analyzer/src/generated/parser.dart';
-import 'package:analyzer/src/generated/source.dart';
-import 'package:analyzer/src/generated/utilities_collection.dart';
-import 'package:analyzer/src/summary/api_signature.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'
-    show ResynthesizerResultProvider, SummaryDataStore;
-import 'package:analyzer/src/summary/summarize_ast.dart'
-    show serializeAstUnlinked;
-import 'package:analyzer/src/summary/summarize_elements.dart'
-    show PackageBundleAssembler;
-import 'package:convert/convert.dart';
-import 'package:crypto/crypto.dart';
-import 'package:meta/meta.dart';
-import 'package:path/path.dart' as pathos;
-
-/**
- * Unlinked and linked information about a [PubPackage].
- */
-class LinkedPubPackage {
-  final PubPackage package;
-  final PackageBundle unlinked;
-  final PackageBundle linked;
-
-  final String linkedHash;
-
-  LinkedPubPackage(this.package, this.unlinked, this.linked, this.linkedHash);
-
-  @override
-  String toString() => package.toString();
-}
-
-/**
- * A package in the pub cache.
- */
-class PubPackage {
-  final String name;
-  final Folder libFolder;
-
-  PubPackage(this.name, this.libFolder);
-
-  Folder get folder => libFolder.parent;
-
-  @override
-  int get hashCode => libFolder.hashCode;
-
-  @override
-  bool operator ==(other) {
-    return other is PubPackage && other.libFolder == libFolder;
-  }
-
-  @override
-  String toString() => '($name in $folder)';
-}
-
-/**
- * Class that manages summaries for pub packages.
- *
- * The client should call [getLinkedBundles] after creating a new
- * [AnalysisContext] and configuring its source factory, but before computing
- * any analysis results.  The returned linked bundles can be used to create and
- * configure [ResynthesizerResultProvider] for the context.
- */
-class PubSummaryManager {
-  static const UNLINKED_NAME = 'unlinked.ds';
-  static const UNLINKED_SPEC_NAME = 'unlinked_spec.ds';
-
-  /**
-   * If `true` (by default), then linking new bundles is allowed.
-   * Otherwise only using existing cached bundles can be used.
-   */
-  final bool allowLinking;
-
-  /**
-   * See [PackageBundleAssembler.currentMajorVersion].
-   */
-  final int majorVersion;
-
-  final ResourceProvider resourceProvider;
-
-  /**
-   * The name of the temporary file that is used for atomic writes.
-   */
-  final String tempFileName;
-
-  /**
-   * The map from [PubPackage]s to their unlinked [PackageBundle]s in the pub
-   * cache.
-   */
-  final Map<PubPackage, PackageBundle> unlinkedBundleMap =
-      new HashMap<PubPackage, PackageBundle>();
-
-  /**
-   * The map from linked file paths to the corresponding linked bundles.
-   */
-  final Map<String, PackageBundle> linkedBundleMap =
-      new HashMap<String, PackageBundle>();
-
-  /**
-   * The set of packages to compute unlinked summaries for.
-   */
-  final Set<PubPackage> packagesToComputeUnlinked = new Set<PubPackage>();
-
-  /**
-   * The set of already processed packages, which we have already checked
-   * for their unlinked bundle existence, or scheduled its computing.
-   */
-  final Set<PubPackage> seenPackages = new Set<PubPackage>();
-
-  /**
-   * The [Completer] that completes when computing of all scheduled unlinked
-   * bundles is complete.
-   */
-  Completer _onUnlinkedCompleteCompleter;
-
-  PubSummaryManager(this.resourceProvider, this.tempFileName,
-      {@visibleForTesting this.allowLinking: true,
-      @visibleForTesting this.majorVersion:
-          PackageBundleAssembler.currentMajorVersion});
-
-  /**
-   * The [Future] that completes when computing of all scheduled unlinked
-   * bundles is complete.
-   */
-  Future get onUnlinkedComplete {
-    if (packagesToComputeUnlinked.isEmpty) {
-      return new Future.value();
-    }
-    _onUnlinkedCompleteCompleter ??= new Completer();
-    return _onUnlinkedCompleteCompleter.future;
-  }
-
-  /**
-   * Return the [pathos.Context] corresponding to the [resourceProvider].
-   */
-  pathos.Context get pathContext => resourceProvider.pathContext;
-
-  /**
-   * Complete when the unlinked bundles for the package with the given [name]
-   * and the [libFolder] are computed and written to the files.
-   *
-   * This method is intended to be used for generating unlinked bundles for
-   * the `Flutter` packages.
-   */
-  Future<Null> computeUnlinkedForFolder(String name, Folder libFolder) async {
-    PubPackage package = new PubPackage(name, libFolder);
-    _scheduleUnlinked(package);
-    await onUnlinkedComplete;
-  }
-
-  /**
-   * Return the list of linked [LinkedPubPackage]s that can be provided at this
-   * time for a subset of the packages used by the given [context].  If
-   * information about some of the used packages is not available yet, schedule
-   * its computation, so that it might be available later for other contexts
-   * referencing the same packages.
-   */
-  List<LinkedPubPackage> getLinkedBundles(AnalysisContext context) {
-    return new _ContextLinker(this, context).getLinkedBundles();
-  }
-
-  /**
-   * Return all available unlinked [PackageBundle]s for the given [context],
-   * maybe an empty map, but not `null`.
-   */
-  @visibleForTesting
-  Map<PubPackage, PackageBundle> getUnlinkedBundles(AnalysisContext context) {
-    bool strong = context.analysisOptions.strongMode;
-    Map<PubPackage, PackageBundle> unlinkedBundles =
-        new HashMap<PubPackage, PackageBundle>();
-    Map<String, List<Folder>> packageMap = context.sourceFactory.packageMap;
-    if (packageMap != null) {
-      packageMap.forEach((String packageName, List<Folder> libFolders) {
-        if (libFolders.length == 1) {
-          Folder libFolder = libFolders.first;
-          PubPackage package = new PubPackage(packageName, libFolder);
-          PackageBundle unlinkedBundle =
-              _getUnlinkedOrSchedule(package, strong);
-          if (unlinkedBundle != null) {
-            unlinkedBundles[package] = unlinkedBundle;
-          }
-        }
-      });
-    }
-    return unlinkedBundles;
-  }
-
-  /**
-   * Compute unlinked bundle for a package from [packagesToComputeUnlinked],
-   * and schedule delayed computation for the next package, if any.
-   */
-  void _computeNextUnlinked() {
-    if (packagesToComputeUnlinked.isNotEmpty) {
-      PubPackage package = packagesToComputeUnlinked.first;
-      _computeUnlinked(package, false);
-      _computeUnlinked(package, true);
-      packagesToComputeUnlinked.remove(package);
-      _scheduleNextUnlinked();
-    } else {
-      if (_onUnlinkedCompleteCompleter != null) {
-        _onUnlinkedCompleteCompleter.complete(true);
-        _onUnlinkedCompleteCompleter = null;
-      }
-    }
-  }
-
-  /**
-   * Compute the unlinked bundle for the package with the given path, put
-   * it in the [unlinkedBundleMap] and store into the [resourceProvider].
-   *
-   * TODO(scheglov) Consider moving into separate isolate(s).
-   */
-  void _computeUnlinked(PubPackage package, bool strong) {
-    Folder libFolder = package.libFolder;
-    String libPath = libFolder.path + pathContext.separator;
-    PackageBundleAssembler assembler = new PackageBundleAssembler();
-
-    /**
-     * Return the `package` [Uri] for the given [path] in the `lib` folder
-     * of the current package.
-     */
-    Uri getUri(String path) {
-      String pathInLib = path.substring(libPath.length);
-      String uriPath = pathos.posix.joinAll(pathContext.split(pathInLib));
-      String uriStr = 'package:${package.name}/$uriPath';
-      return Uri.parse(uriStr);
-    }
-
-    /**
-     * If the given [file] is a Dart file, add its unlinked unit.
-     */
-    void addDartFile(File file) {
-      String path = file.path;
-      if (AnalysisEngine.isDartFileName(path)) {
-        Uri uri = getUri(path);
-        Source source = file.createSource(uri);
-        CompilationUnit unit = _parse(source, strong);
-        UnlinkedUnitBuilder unlinkedUnit = serializeAstUnlinked(unit);
-        assembler.addUnlinkedUnit(source, unlinkedUnit);
-      }
-    }
-
-    /**
-     * Visit the [folder] recursively.
-     */
-    void addDartFiles(Folder folder) {
-      List<Resource> children = folder.getChildren();
-      for (Resource child in children) {
-        if (child is File) {
-          addDartFile(child);
-        }
-      }
-      for (Resource child in children) {
-        if (child is Folder) {
-          addDartFiles(child);
-        }
-      }
-    }
-
-    try {
-      addDartFiles(libFolder);
-      PackageBundleBuilder bundleWriter = assembler.assemble();
-      bundleWriter.majorVersion = majorVersion;
-      List<int> bytes = bundleWriter.toBuffer();
-      String fileName = _getUnlinkedName(strong);
-      _writeAtomic(package.folder, fileName, bytes);
-    } on FileSystemException {
-      // Ignore file system exceptions.
-    }
-  }
-
-  /**
-   * Return the name of the file for an unlinked bundle, in strong or spec mode.
-   */
-  String _getUnlinkedName(bool strong) {
-    if (strong) {
-      return UNLINKED_NAME;
-    } else {
-      return UNLINKED_SPEC_NAME;
-    }
-  }
-
-  /**
-   * Return the unlinked [PackageBundle] for the given [package]. If the bundle
-   * has not been compute yet, return `null` and schedule its computation.
-   */
-  PackageBundle _getUnlinkedOrSchedule(PubPackage package, bool strong) {
-    // Try to find in the cache.
-    PackageBundle bundle = unlinkedBundleMap[package];
-    if (bundle != null) {
-      return bundle;
-    }
-
-    // Try to read from the file system.
-    String fileName = _getUnlinkedName(strong);
-    File file = package.folder.getChildAssumingFile(fileName);
-    if (file.exists) {
-      try {
-        List<int> bytes = file.readAsBytesSync();
-        bundle = new PackageBundle.fromBuffer(bytes);
-      } on FileSystemException {
-        // Ignore file system exceptions.
-      }
-    }
-
-    // Verify compatibility and consistency.
-    bool isInPubCache = isPathInPubCache(pathContext, package.folder.path);
-    if (bundle != null &&
-        bundle.majorVersion == majorVersion &&
-        (isInPubCache || _isConsistent(package, bundle))) {
-      unlinkedBundleMap[package] = bundle;
-      return bundle;
-    }
-
-    // Schedule computation in the background, if in the pub cache.
-    if (isInPubCache) {
-      if (seenPackages.add(package)) {
-        _scheduleUnlinked(package);
-      }
-    }
-
-    // The bundle is not available.
-    return null;
-  }
-
-  /**
-   * Return `true` if content hashes for the [package] library files are the
-   * same the hashes in the unlinked [bundle].
-   */
-  bool _isConsistent(PubPackage package, PackageBundle bundle) {
-    List<String> actualHashes = <String>[];
-
-    /**
-     * If the given [file] is a Dart file, add its content hash.
-     */
-    void hashDartFile(File file) {
-      String path = file.path;
-      if (AnalysisEngine.isDartFileName(path)) {
-        List<int> fileBytes = file.readAsBytesSync();
-        List<int> hashBytes = md5.convert(fileBytes).bytes;
-        String hashHex = hex.encode(hashBytes);
-        actualHashes.add(hashHex);
-      }
-    }
-
-    /**
-     * Visit the [folder] recursively.
-     */
-    void hashDartFiles(Folder folder) {
-      List<Resource> children = folder.getChildren();
-      for (Resource child in children) {
-        if (child is File) {
-          hashDartFile(child);
-        } else if (child is Folder) {
-          hashDartFiles(child);
-        }
-      }
-    }
-
-    // Recursively compute hashes of the `lib` folder Dart files.
-    try {
-      hashDartFiles(package.libFolder);
-    } on FileSystemException {
-      return false;
-    }
-
-    // Compare sorted actual and bundle unit hashes.
-    List<String> bundleHashes = bundle.unlinkedUnitHashes.toList()..sort();
-    actualHashes.sort();
-    return listsEqual(actualHashes, bundleHashes);
-  }
-
-  /**
-   * Parse the given [source] into AST.
-   */
-  CompilationUnit _parse(Source source, bool strong) {
-    String code = source.contents.data;
-    AnalysisErrorListener errorListener = AnalysisErrorListener.NULL_LISTENER;
-    CharSequenceReader reader = new CharSequenceReader(code);
-    Scanner scanner = new Scanner(source, reader, errorListener);
-    scanner.scanGenericMethodComments = strong;
-    Token token = scanner.tokenize();
-    LineInfo lineInfo = new LineInfo(scanner.lineStarts);
-    Parser parser = new Parser(source, errorListener);
-    parser.parseGenericMethodComments = strong;
-    CompilationUnit unit = parser.parseCompilationUnit(token);
-    unit.lineInfo = lineInfo;
-    return unit;
-  }
-
-  /**
-   * Schedule delayed computation of the next package unlinked bundle from the
-   * set of [packagesToComputeUnlinked].  We delay each computation because we
-   * want operations in analysis server to proceed, and computing bundles of
-   * packages is a background task.
-   */
-  void _scheduleNextUnlinked() {
-    new Future.delayed(new Duration(milliseconds: 10), _computeNextUnlinked);
-  }
-
-  /**
-   * Schedule computing unlinked bundles for the given [package].
-   */
-  void _scheduleUnlinked(PubPackage package) {
-    if (packagesToComputeUnlinked.isEmpty) {
-      _scheduleNextUnlinked();
-    }
-    packagesToComputeUnlinked.add(package);
-  }
-
-  /**
-   * Atomically write the given [bytes] into the file in the [folder].
-   */
-  void _writeAtomic(Folder folder, String fileName, List<int> bytes) {
-    String filePath = folder.getChildAssumingFile(fileName).path;
-    File tempFile = folder.getChildAssumingFile(tempFileName);
-    tempFile.writeAsBytesSync(bytes);
-    tempFile.renameSync(filePath);
-  }
-
-  /**
-   * If the given [uri] has the `package` scheme, return the name of the
-   * package that contains the referenced resource.  Otherwise return `null`.
-   *
-   * For example `package:foo/bar.dart` => `foo`.
-   */
-  static String getPackageName(String uri) {
-    const String PACKAGE_SCHEME = 'package:';
-    if (uri.startsWith(PACKAGE_SCHEME)) {
-      int index = uri.indexOf('/');
-      if (index != -1) {
-        return uri.substring(PACKAGE_SCHEME.length, index);
-      }
-    }
-    return null;
-  }
-
-  /**
-   * Return `true` if the given absolute [path] is in the pub cache.
-   */
-  static bool isPathInPubCache(pathos.Context pathContext, String path) {
-    List<String> parts = pathContext.split(path);
-    for (int i = 0; i < parts.length - 1; i++) {
-      if (parts[i] == '.pub-cache') {
-        return true;
-      }
-      if (parts[i] == 'Pub' && parts[i + 1] == 'Cache') {
-        return true;
-      }
-    }
-    return false;
-  }
-}
-
-class _ContextLinker {
-  final PubSummaryManager manager;
-  final AnalysisContext context;
-
-  final strong;
-  final _ListedPackages listedPackages;
-  final PackageBundle sdkBundle;
-
-  final List<_LinkNode> nodes = <_LinkNode>[];
-  final Map<String, _LinkNode> packageToNode = <String, _LinkNode>{};
-
-  _ContextLinker(this.manager, AnalysisContext context)
-      : context = context,
-        strong = context.analysisOptions.strongMode,
-        listedPackages = new _ListedPackages(context.sourceFactory),
-        sdkBundle = context.sourceFactory.dartSdk.getLinkedBundle();
-
-  /**
-   * Return the list of linked [LinkedPubPackage]s that can be provided at this
-   * time for a subset of the packages used by the [context].
-   */
-  List<LinkedPubPackage> getLinkedBundles() {
-//    Stopwatch timer = new Stopwatch()..start();
-
-    if (sdkBundle == null) {
-      return const <LinkedPubPackage>[];
-    }
-
-    Map<PubPackage, PackageBundle> unlinkedBundles =
-        manager.getUnlinkedBundles(context);
-
-    // TODO(scheglov) remove debug output after optimizing
-//    print('LOADED ${unlinkedBundles.length} unlinked bundles'
-//        ' in ${timer.elapsedMilliseconds} ms');
-//    timer..reset();
-
-    // If no unlinked bundles, there is nothing we can try to link.
-    if (unlinkedBundles.isEmpty) {
-      return const <LinkedPubPackage>[];
-    }
-
-    // Create nodes for packages.
-    unlinkedBundles.forEach((package, unlinked) {
-      _LinkNode node = new _LinkNode(this, package, unlinked);
-      nodes.add(node);
-      packageToNode[package.name] = node;
-    });
-
-    // Compute transitive dependencies, mark some nodes as failed.
-    for (_LinkNode node in nodes) {
-      node.computeTransitiveDependencies();
-    }
-
-    // Attempt to read existing linked bundles.
-    for (_LinkNode node in nodes) {
-      _readLinked(node);
-    }
-
-    // Link new packages, if allowed.
-    if (manager.allowLinking) {
-      _link();
-    }
-
-    // Create successfully linked packages.
-    List<LinkedPubPackage> linkedPackages = <LinkedPubPackage>[];
-    for (_LinkNode node in nodes) {
-      if (node.linked != null) {
-        linkedPackages.add(new LinkedPubPackage(
-            node.package, node.unlinked, node.linked, node.linkedHash));
-      }
-    }
-
-    // TODO(scheglov) remove debug output after optimizing
-//    print('LINKED ${linkedPackages.length} bundles'
-//        ' in ${timer.elapsedMilliseconds} ms');
-
-    // Done.
-    return linkedPackages;
-  }
-
-  String _getDeclaredVariable(String name) {
-    return context.declaredVariables.get(name);
-  }
-
-  /**
-   * Return the name of the file for a linked bundle, in strong or spec mode.
-   */
-  String _getLinkedName(String hash) {
-    if (strong) {
-      return 'linked_$hash.ds';
-    } else {
-      return 'linked_spec_$hash.ds';
-    }
-  }
-
-  void _link() {
-    // Fill the store with bundles.
-    // Append the linked SDK bundle.
-    // Append unlinked and (if read from a cache) linked package bundles.
-    SummaryDataStore store = new SummaryDataStore(const <String>[]);
-    store.addBundle(null, sdkBundle);
-    for (_LinkNode node in nodes) {
-      store.addBundle(null, node.unlinked);
-      if (node.linked != null) {
-        store.addBundle(null, node.linked);
-      }
-    }
-
-    // Prepare URIs to link.
-    Map<String, _LinkNode> uriToNode = <String, _LinkNode>{};
-    for (_LinkNode node in nodes) {
-      if (!node.isReady) {
-        for (String uri in node.unlinked.unlinkedUnitUris) {
-          uriToNode[uri] = node;
-        }
-      }
-    }
-    Set<String> libraryUris = uriToNode.keys.toSet();
-
-    // Perform linking.
-    Map<String, LinkedLibraryBuilder> linkedLibraries =
-        link(libraryUris, (String uri) {
-      return store.linkedMap[uri];
-    }, (String uri) {
-      return store.unlinkedMap[uri];
-    }, _getDeclaredVariable, strong);
-
-    // Assemble newly linked bundles.
-    for (_LinkNode node in nodes) {
-      if (!node.isReady) {
-        PackageBundleAssembler assembler = new PackageBundleAssembler();
-        linkedLibraries.forEach((uri, linkedLibrary) {
-          if (identical(uriToNode[uri], node)) {
-            assembler.addLinkedLibrary(uri, linkedLibrary);
-          }
-        });
-        List<int> bytes = assembler.assemble().toBuffer();
-        node.linkedNewBytes = bytes;
-        node.linked = new PackageBundle.fromBuffer(bytes);
-      }
-    }
-
-    // Write newly linked bundles.
-    for (_LinkNode node in nodes) {
-      _writeLinked(node);
-    }
-  }
-
-  /**
-   * Attempt to find the linked bundle that corresponds to the given [node]
-   * with all its transitive dependencies and put it into [_LinkNode.linked].
-   */
-  void _readLinked(_LinkNode node) {
-    String hash = node.linkedHash;
-    if (hash != null) {
-      String fileName = _getLinkedName(hash);
-      File file = node.package.folder.getChildAssumingFile(fileName);
-      // Try to find in the cache.
-      PackageBundle linked = manager.linkedBundleMap[file.path];
-      if (linked != null) {
-        node.linked = linked;
-        return;
-      }
-      // Try to read from the file system.
-      if (file.exists) {
-        try {
-          List<int> bytes = file.readAsBytesSync();
-          linked = new PackageBundle.fromBuffer(bytes);
-          manager.linkedBundleMap[file.path] = linked;
-          node.linked = linked;
-        } on FileSystemException {
-          // Ignore file system exceptions.
-        }
-      }
-    }
-  }
-
-  /**
-   * If a new linked bundle was linked for the given [node], write the bundle
-   * into the memory cache and the file system.
-   */
-  void _writeLinked(_LinkNode node) {
-    String hash = node.linkedHash;
-    if (hash != null && node.linkedNewBytes != null) {
-      String fileName = _getLinkedName(hash);
-      File file = node.package.folder.getChildAssumingFile(fileName);
-      manager.linkedBundleMap[file.path] = node.linked;
-      manager._writeAtomic(node.package.folder, fileName, node.linkedNewBytes);
-    }
-  }
-}
-
-/**
- * Information about a package to link.
- */
-class _LinkNode {
-  final _ContextLinker linker;
-  final PubPackage package;
-  final PackageBundle unlinked;
-
-  bool failed = false;
-  Set<_LinkNode> transitiveDependencies;
-
-  List<_LinkNode> _dependencies;
-  String _linkedHash;
-
-  List<int> linkedNewBytes;
-  PackageBundle linked;
-
-  _LinkNode(this.linker, this.package, this.unlinked);
-
-  /**
-   * Retrieve the dependencies of this node.
-   */
-  List<_LinkNode> get dependencies {
-    if (_dependencies == null) {
-      Set<_LinkNode> dependencies = new Set<_LinkNode>();
-
-      void appendDependency(String uriStr) {
-        Uri uri = Uri.parse(uriStr);
-        if (!uri.hasScheme) {
-          // A relative path in this package, skip it.
-        } else if (uri.scheme == 'dart') {
-          // Dependency on the SDK is implicit and always added.
-          // The SDK linked bundle is precomputed before linking packages.
-        } else if (uriStr.startsWith('package:')) {
-          String package = PubSummaryManager.getPackageName(uriStr);
-          _LinkNode packageNode = linker.packageToNode[package];
-          if (packageNode == null && linker.listedPackages.isListed(uriStr)) {
-            failed = true;
-          }
-          if (packageNode != null) {
-            dependencies.add(packageNode);
-          }
-        } else {
-          failed = true;
-        }
-      }
-
-      for (UnlinkedUnit unit in unlinked.unlinkedUnits) {
-        for (UnlinkedImport import in unit.imports) {
-          if (!import.isImplicit) {
-            appendDependency(import.uri);
-          }
-        }
-        for (UnlinkedExportPublic export in unit.publicNamespace.exports) {
-          appendDependency(export.uri);
-        }
-      }
-
-      _dependencies = dependencies.toList();
-    }
-    return _dependencies;
-  }
-
-  /**
-   * Return `true` is the node is ready - has the linked bundle or failed (does
-   * not have all required dependencies).
-   */
-  bool get isReady => linked != null || failed;
-
-  /**
-   * Return the hash string that corresponds to this linked bundle in the
-   * context of its SDK bundle and transitive dependencies.  Return `null` if
-   * the hash computation fails, because for example the full transitive
-   * dependencies cannot computed.
-   */
-  String get linkedHash {
-    if (_linkedHash == null && transitiveDependencies != null) {
-      ApiSignature signature = new ApiSignature();
-      // Add all unlinked API signatures.
-      List<String> signatures = <String>[];
-      signatures.add(linker.sdkBundle.apiSignature);
-      transitiveDependencies
-          .map((node) => node.unlinked.apiSignature)
-          .forEach(signatures.add);
-      signatures.sort();
-      signatures.forEach(signature.addString);
-      // Combine into a single hash.
-      appendDeclaredVariables(signature);
-      _linkedHash = signature.toHex();
-    }
-    return _linkedHash;
-  }
-
-  /**
-   * Append names and values of all referenced declared variables (even the
-   * ones without actually declared values) to the given [signature].
-   */
-  void appendDeclaredVariables(ApiSignature signature) {
-    Set<String> nameSet = new Set<String>();
-    for (_LinkNode node in transitiveDependencies) {
-      for (UnlinkedUnit unit in node.unlinked.unlinkedUnits) {
-        for (UnlinkedImport import in unit.imports) {
-          for (UnlinkedConfiguration configuration in import.configurations) {
-            nameSet.add(configuration.name);
-          }
-        }
-        for (UnlinkedExportPublic export in unit.publicNamespace.exports) {
-          for (UnlinkedConfiguration configuration in export.configurations) {
-            nameSet.add(configuration.name);
-          }
-        }
-      }
-    }
-    List<String> sortedNameList = nameSet.toList()..sort();
-    signature.addInt(sortedNameList.length);
-    for (String name in sortedNameList) {
-      signature.addString(name);
-      signature.addString(linker._getDeclaredVariable(name) ?? '');
-    }
-  }
-
-  /**
-   * Compute the set of existing transitive dependencies for this node.
-   * If any `package` dependency cannot be resolved, but it is one of the
-   * [listedPackages] then set [failed] to `true`.
-   * Only [unlinked] is used, so this method can be called before linking.
-   */
-  void computeTransitiveDependencies() {
-    if (transitiveDependencies == null) {
-      transitiveDependencies = new Set<_LinkNode>();
-
-      void appendDependencies(_LinkNode node) {
-        if (transitiveDependencies.add(node)) {
-          node.dependencies.forEach(appendDependencies);
-        }
-      }
-
-      appendDependencies(this);
-      if (transitiveDependencies.any((node) => node.failed)) {
-        failed = true;
-      }
-    }
-  }
-
-  @override
-  String toString() => package.toString();
-}
-
-/**
- * The set of package names that are listed in the `.packages` file of a
- * context.  These are the only packages, references to which can
- * be possibly resolved in the context.  Nodes that reference a `package:` URI
- * without the unlinked bundle, so without the node, cannot be linked.
- */
-class _ListedPackages {
-  final Set<String> names = new Set<String>();
-
-  _ListedPackages(SourceFactory sourceFactory) {
-    Map<String, List<Folder>> map = sourceFactory.packageMap;
-    if (map != null) {
-      names.addAll(map.keys);
-    }
-  }
-
-  /**
-   * Check whether the given `package:` [uri] is listed in the package map.
-   */
-  bool isListed(String uri) {
-    String package = PubSummaryManager.getPackageName(uri);
-    return names.contains(package);
-  }
-}