pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart

// Copyright (c) 2015, 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 'package:analysis_server/src/provisional/completion/completion_core.dart'
    show CompletionContributor, CompletionRequest;
import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
import 'package:analysis_server/src/services/completion/completion_core.dart';
import 'package:analysis_server/src/services/completion/completion_performance.dart';
import 'package:analysis_server/src/services/completion/dart/arglist_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/combinator_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/common_usage_sorter.dart';
import 'package:analysis_server/src/services/completion/dart/contribution_sorter.dart';
import 'package:analysis_server/src/services/completion/dart/field_formal_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/imported_reference_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/inherited_reference_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/keyword_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/label_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/library_member_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/library_prefix_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/local_constructor_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/local_library_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/local_reference_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/named_constructor_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/static_member_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/type_member_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/uri_contributor.dart';
import 'package:analysis_server/src/services/completion/dart/variable_name_contributor.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:analyzer/file_system/file_system.dart';
import 'package:analyzer/src/dart/analysis/driver.dart';
import 'package:analyzer/src/generated/engine.dart' hide AnalysisResult;
import 'package:analyzer/src/generated/source.dart';
import 'package:analyzer/task/model.dart';
import 'package:analyzer_plugin/protocol/protocol_common.dart';
import 'package:analyzer_plugin/src/utilities/completion/completion_target.dart';
import 'package:analyzer_plugin/src/utilities/completion/optype.dart';

/**
 * [DartCompletionManager] determines if a completion request is Dart specific
 * and forwards those requests to all [DartCompletionContributor]s.
 */
class DartCompletionManager implements CompletionContributor {
  /**
   * The [contributionSorter] is a long-lived object that isn't allowed
   * to maintain state between calls to [DartContributionSorter#sort(...)].
   */
  static DartContributionSorter contributionSorter = new CommonUsageSorter();

  @override
  Future<List<CompletionSuggestion>> computeSuggestions(
      CompletionRequest request) async {
    request.checkAborted();
    if (!AnalysisEngine.isDartFileName(request.source.shortName)) {
      return EMPTY_LIST;
    }

    CompletionPerformance performance =
        (request as CompletionRequestImpl).performance;
    DartCompletionRequestImpl dartRequest =
        await DartCompletionRequestImpl.from(request);

    // Don't suggest in comments.
    if (dartRequest.target.isCommentText) {
      return EMPTY_LIST;
    }

    SourceRange range =
        dartRequest.target.computeReplacementRange(dartRequest.offset);
    (request as CompletionRequestImpl)
      ..replacementOffset = range.offset
      ..replacementLength = range.length;

    // Request Dart specific completions from each contributor
    Map<String, CompletionSuggestion> suggestionMap =
        <String, CompletionSuggestion>{};
    List<DartCompletionContributor> contributors = <DartCompletionContributor>[
      new ArgListContributor(),
      new CombinatorContributor(),
      new FieldFormalContributor(),
      new ImportedReferenceContributor(),
      new InheritedReferenceContributor(),
      new KeywordContributor(),
      new LabelContributor(),
      new LibraryMemberContributor(),
      new LibraryPrefixContributor(),
      new LocalConstructorContributor(),
      new LocalLibraryContributor(),
      new LocalReferenceContributor(),
      new NamedConstructorContributor(),
      // new OverrideContributor(),
      new StaticMemberContributor(),
      new TypeMemberContributor(),
      new UriContributor(),
      new VariableNameContributor()
    ];
    for (DartCompletionContributor contributor in contributors) {
      String contributorTag =
          'DartCompletionManager - ${contributor.runtimeType}';
      performance.logStartTime(contributorTag);
      List<CompletionSuggestion> contributorSuggestions =
          await contributor.computeSuggestions(dartRequest);
      performance.logElapseTime(contributorTag);
      request.checkAborted();

      for (CompletionSuggestion newSuggestion in contributorSuggestions) {
        var oldSuggestion = suggestionMap.putIfAbsent(
            newSuggestion.completion, () => newSuggestion);
        if (newSuggestion != oldSuggestion &&
            newSuggestion.relevance > oldSuggestion.relevance) {
          suggestionMap[newSuggestion.completion] = newSuggestion;
        }
      }
    }

    // Adjust suggestion relevance before returning
    List<CompletionSuggestion> suggestions = suggestionMap.values.toList();
    const SORT_TAG = 'DartCompletionManager - sort';
    performance.logStartTime(SORT_TAG);
    await contributionSorter.sort(dartRequest, suggestions);
    performance.logElapseTime(SORT_TAG);
    request.checkAborted();
    return suggestions;
  }
}

/**
 * The information about a requested list of completions within a Dart file.
 */
class DartCompletionRequestImpl implements DartCompletionRequest {
  @override
  final AnalysisResult result;

  @override
  final ResourceProvider resourceProvider;

  @override
  final InterfaceType objectType;

  @override
  final Source source;

  @override
  final int offset;

  @override
  Expression dotTarget;

  @override
  Source librarySource;

  @override
  CompletionTarget target;

  OpType _opType;

  final CompletionRequest _originalRequest;

  final CompletionPerformance performance;

  DartCompletionRequestImpl._(
      this.result,
      this.resourceProvider,
      this.objectType,
      this.librarySource,
      this.source,
      this.offset,
      CompilationUnit unit,
      this._originalRequest,
      this.performance) {
    _updateTargets(unit);
  }

  @override
  bool get includeIdentifiers {
    return opType.includeIdentifiers;
  }

  @override
  LibraryElement get libraryElement {
    //TODO(danrubel) build the library element rather than all the declarations
    CompilationUnit unit = target.unit;
    if (unit != null) {
      CompilationUnitElement elem = unit.element;
      if (elem != null) {
        return elem.library;
      }
    }
    return null;
  }

  OpType get opType {
    if (_opType == null) {
      _opType = new OpType.forCompletion(target, offset);
    }
    return _opType;
  }

  @override
  String get sourceContents => result.content;

  @override
  SourceFactory get sourceFactory => result.sourceFactory;

  /**
   * Throw [AbortCompletion] if the completion request has been aborted.
   */
  void checkAborted() {
    _originalRequest.checkAborted();
  }

  /**
   * Update the completion [target] and [dotTarget] based on the given [unit].
   */
  void _updateTargets(CompilationUnit unit) {
    _opType = null;
    dotTarget = null;
    target = new CompletionTarget.forOffset(unit, offset);
    AstNode node = target.containingNode;
    if (node is MethodInvocation) {
      if (identical(node.methodName, target.entity)) {
        dotTarget = node.realTarget;
      } else if (node.isCascaded && node.operator.offset + 1 == target.offset) {
        dotTarget = node.realTarget;
      }
    }
    if (node is PropertyAccess) {
      if (identical(node.propertyName, target.entity)) {
        dotTarget = node.realTarget;
      } else if (node.isCascaded && node.operator.offset + 1 == target.offset) {
        dotTarget = node.realTarget;
      }
    }
    if (node is PrefixedIdentifier) {
      if (identical(node.identifier, target.entity)) {
        dotTarget = node.prefix;
      }
    }
  }

  /**
   * Return a [Future] that completes with a newly created completion request
   * based on the given [request]. This method will throw [AbortCompletion]
   * if the completion request has been aborted.
   */
  static Future<DartCompletionRequest> from(CompletionRequest request,
      {ResultDescriptor resultDescriptor}) async {
    request.checkAborted();
    CompletionPerformance performance =
        (request as CompletionRequestImpl).performance;
    const BUILD_REQUEST_TAG = 'build DartCompletionRequest';
    performance.logStartTime(BUILD_REQUEST_TAG);

    CompilationUnit unit = request.result.unit;
    Source libSource = unit.element.library.source;
    InterfaceType objectType = request.result.typeProvider.objectType;

    DartCompletionRequestImpl dartRequest = new DartCompletionRequestImpl._(
        request.result,
        request.resourceProvider,
        objectType,
        libSource,
        request.source,
        request.offset,
        unit,
        request,
        performance);

    performance.logElapseTime(BUILD_REQUEST_TAG);
    return dartRequest;
  }
}