Initial implementation of pub summary manager.

pkg/analysis_server/lib/src/pub_summary.dart

+// 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:core' hide Resource;
+
+import 'package:analysis_server/src/analysis_server.dart';
+import 'package:analysis_server/src/context_manager.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/file_system/file_system.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_ast.dart'
+    show serializeAstUnlinked;
+import 'package:analyzer/src/summary/summarize_elements.dart'
+    show PackageBundleAssembler;
+import 'package:analyzer/src/task/dart.dart';
+import 'package:analyzer/src/util/fast_uri.dart';
+import 'package:analyzer/task/dart.dart';
+import 'package:analyzer/task/model.dart';
+import 'package:path/src/context.dart' as pathos;
+
+const visibleForTesting = const Object();
+
+/**
+ * A package in the pub cache.
+ */
+@visibleForTesting

[Brian Wilkerson, 2016/08/05 22:09:14]

nit: There have been requests for this annotation; seems like we should move it
into the meta package and fully support it if we're going to use it.

+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 the manages summaries for pub packages.

[Paul Berry, 2016/08/05 21:43:02]

s/the/that/

[scheglov, 2016/08/05 21:47:41]

Done.

+ */
+class PubSummaryManager {

[Brian Wilkerson, 2016/08/05 22:09:14]

I'd love to see an example of how clients are expected to use this class (maybe
as part of the docs for the class).

+  final ResourceProvider resourceProvider;
+  final AnalysisServer server;
+
+//  /**
+//   * The map from absolute paths of pub packages in the pub cache to their
+//   * unlinked summary bundles.
+//   */
+//  final Map<String, PackageBundle> unlinkedBundleMap =
+//      new HashMap<String, PackageBundle>();
+
+  /**
+   * The set of packages to compute summaries for.
+   */
+  final Set<PubPackage> packagesToSummarize = new Set<PubPackage>();
+
+  /**
+   * The set of already processed packages, which we have already checked
+   * for their unlinked summary existence, or scheduled its computing.
+   */
+  final Set<PubPackage> seenPackages = new Set<PubPackage>();
+
+  /**
+   * The [Completer] that completes when analysis is complete.
+   */
+  Completer _onCompleteCompleter;
+
+  /**
+   * Create a new instance and start listening for [AnalysisServer] and
+   * [AnalysisContext] events, and schedule creating pub summaries.
+   */
+  PubSummaryManager(this.resourceProvider, this.server) {
+    server.onContextsChanged.listen((ContextsChangedEvent event) {
+      for (AnalysisContext context in event.added) {
+        context
+            .onResultChanged(LIBRARY_ELEMENT1)
+            .listen(handleNewLibraryElementEvent);
+      }
+    });
+  }
+
+  /**
+   * The [Future] that completes when computing of all package summaries is
+   * complete.
+   */
+  Future get onComplete {
+    if (packagesToSummarize.isEmpty) {
+      return new Future.value();
+    }
+    _onCompleteCompleter ??= new Completer();
+    return _onCompleteCompleter.future;
+  }
+
+  /**
+   * Return the [pathos.Context] corresponding to the [resourceProvider].
+   */
+  pathos.Context get pathContext => resourceProvider.pathContext;
+
+  /**
+   * If the given [source] has the 'package' scheme, and its path is in the
+   * pub cache, return information about the package that contains the [source].
+   * Otherwise return `null`.
+   */
+  @visibleForTesting
+  PubPackage getPackageInPubCache(AnalysisContext context, Source source) {
+    if (source.uri.scheme == 'package') {
+      String path = source.fullName;
+      if (isPathInPubCache(pathContext, path)) {
+        String packageName = getPackageName(source.uri);
+        if (packageName != null) {
+          List<Folder> libFolders =
+              context.sourceFactory.packageMap[packageName];
+          if (libFolders != null && libFolders.length == 1) {
+            return new PubPackage(packageName, libFolders.first);
+          }
+        }
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Handle [ResultChangedEvent] for [LIBRARY_ELEMENT1] and schedule computing
+   * summary for the library, if it is not ready yet.
+   */
+  @visibleForTesting
+  void handleNewLibraryElementEvent(ResultChangedEvent event) {
+    AnalysisTarget source = event.target;
+    if (event.wasComputed && source is Source) {
+      PubPackage package = getPackageInPubCache(event.context, source);
+      if (package != null && seenPackages.add(package)) {
+        packagesToSummarize.add(package);
+        if (packagesToSummarize.length == 1) {
+          _scheduleNextPackageSummary();

[Brian Wilkerson, 2016/08/05 22:09:13]

If a package 'a' depends on a package 'b', do we need to create a summary for
'b' before we create a summary for 'a', or is that not a constraint when
building unlinked summaries?

[Paul Berry, 2016/08/05 22:29:28]

That is not a constraint when building unlinked summaries.

+        }
+      }
+    }
+  }
+
+  /**
+   * Compute summary for a package from [packagesToSummarize], and schedule
+   * delayed computation of the next package summary, if any.
+   */
+  void _computeNextPackageSummary() {
+    if (packagesToSummarize.isNotEmpty) {
+      PubPackage package = packagesToSummarize.first;
+      _computeUnlinkedPackageSummary(package);
+      packagesToSummarize.remove(package);
+      _scheduleNextPackageSummary();
+    } else {
+      if (_onCompleteCompleter != null) {
+        _onCompleteCompleter.complete(true);
+        _onCompleteCompleter = null;
+      }
+    }
+  }
+
+  /**
+   * Compute the unlinked summary 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 _computeUnlinkedPackageSummary(PubPackage package) {
+    AnalysisContext context = AnalysisEngine.instance.createAnalysisContext();
+    context.sourceFactory = new SourceFactory(
+        <UriResolver>[new DartUriResolver(server.sdkManager.anySdk)]);

[Brian Wilkerson, 2016/08/05 22:09:14]

This won't let us distinguish between packages built for web and packages built
for flutter. Maybe that doesn't matter for an unliked summary.

Also, don't we need a PackageUriResolver for 'package:' URI's used within the
package being summarized? Or do we not need it because we're producing an
unlinked summary?

[Paul Berry, 2016/08/05 22:29:28]

I'm not aware of any constraints Flutter imposes that would make a difference to
an unlinked summary, so I think this is ok.
Correct, we don't need this because the act of producing an unlinked summary
doesn't do any URI resolution.  (If it did, it would defeat the purpose, because
part of the idea of an unlinked summary is that it can be safely re-used in a
situation where URI resolution is different).

+
+    Folder libFolder = package.libFolder;
+    String libPath = libFolder.path + pathContext.separator;
+    PackageBundleAssembler assembler = new PackageBundleAssembler();
+
+    /**
+     * If the given [file] is a Dart file, the unlinked summary of it.
+     */
+    void addDartFile(File file) {
+      String path = file.path;
+      if (AnalysisEngine.isDartFileName(path)) {
+        String pathInLib = path.substring(libPath.length);
+        String uriStr = 'package:${package.name}/$pathInLib';

[Paul Berry, 2016/08/05 21:43:02]

This looks incorrect for Windows, since on Windows, pathInLib will contain
backslashes.

[scheglov, 2016/08/05 21:47:41]

Fixed.

+        Uri uri = FastUri.parse(uriStr);
+        Source source = file.createSource(uri);
+        CompilationUnit unit = context.computeResult(source, PARSED_UNIT);
+        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) {

[Brian Wilkerson, 2016/08/05 22:09:14]

Does the order in which we add the children matter (do children in a folder need
to be added before children in subfolders)? If not, consider combining these two
loops.

+        if (child is Folder) {
+          addDartFiles(child);
+        }
+      }
+    }
+
+    try {
+      addDartFiles(libFolder);
+      List<int> bytes = assembler.assemble().toBuffer();
+      package.folder
+          .getChildAssumingFile('summary_spec.full.ds')
+          .writeAsBytesSync(bytes);
+    } on FileSystemException {
+      // Ignore file system exceptions.
+    }
+  }
+
+  /**
+   * Schedule delayed computation of the next package summary from the set of
+   * [packagesToSummarize].  We delay each computation because we want
+   * operations in analysis server to proceed, and computing summaries of
+   * packages is a background task.
+   */
+  void _scheduleNextPackageSummary() {
+    new Future.delayed(
+        new Duration(milliseconds: 10), _computeNextPackageSummary);
+  }
+
+  /**
+   * If the given [uri] has the `package` scheme, return the names of the

[Paul Berry, 2016/08/05 21:43:02]

s/names/name/

[scheglov, 2016/08/05 21:47:41]

Done.

+   * package that contains the referenced resource.  Otherwise return `null`.
+   *
+   * For example `package:foo/bar.dart` => `foo`.
+   */
+  static String getPackageName(Uri uri) {
+    const String PACKAGE_SCHEME = 'package:';
+    String text = uri.toString();
+    if (text.startsWith(PACKAGE_SCHEME)) {
+      int index = text.indexOf('/');
+      if (index != -1) {
+        return text.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;
+  }
+}