pkg/analysis_server/lib/src/services/completion/dart_completion_manager.dart - sdk.git - Git at Google

 // Copyright (c) 2014, 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.

 library services.completion.dart;

 import 'dart:async';

 import 'package:analysis_server/completion/completion_core.dart'
     show CompletionRequest;
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/arglist_contributor.dart';
 import 'package:analysis_server/src/services/completion/combinator_contributor.dart';
 import 'package:analysis_server/src/services/completion/common_usage_computer.dart';
 import 'package:analysis_server/src/services/completion/completion_manager.dart';
 import 'package:analysis_server/src/services/completion/completion_target.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_cache.dart';
 import 'package:analysis_server/src/services/completion/import_uri_contributor.dart';
 import 'package:analysis_server/src/services/completion/imported_reference_contributor.dart';
 import 'package:analysis_server/src/services/completion/keyword_contributor.dart';
 import 'package:analysis_server/src/services/completion/local_reference_contributor.dart';
 import 'package:analysis_server/src/services/completion/optype.dart';
 import 'package:analysis_server/src/services/completion/prefixed_element_contributor.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';

 const int DART_RELEVANCE_COMMON_USAGE = 1200;
 const int DART_RELEVANCE_DEFAULT = 1000;
 const int DART_RELEVANCE_HIGH = 2000;
 const int DART_RELEVANCE_INHERITED_ACCESSOR = 1057;
 const int DART_RELEVANCE_INHERITED_FIELD = 1058;
 const int DART_RELEVANCE_INHERITED_METHOD = 1057;
 const int DART_RELEVANCE_KEYWORD = 1055;
 const int DART_RELEVANCE_LOCAL_ACCESSOR = 1057;
 const int DART_RELEVANCE_LOCAL_FIELD = 1058;
 const int DART_RELEVANCE_LOCAL_FUNCTION = 1056;
 const int DART_RELEVANCE_LOCAL_METHOD = 1057;
 const int DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE = 1056;
 const int DART_RELEVANCE_LOCAL_VARIABLE = 1059;
 const int DART_RELEVANCE_LOW = 500;
 const int DART_RELEVANCE_NAMED_PARAMETER = 1060;
 const int DART_RELEVANCE_PARAMETER = 1059;

 /**
  * The base class for contributing code completion suggestions.
  */
 abstract class DartCompletionContributor {
   /**
    * Computes the initial set of [CompletionSuggestion]s based on
    * the given completion context. The compilation unit and completion node
    * in the given completion context may not be resolved.
    * This method should execute quickly and not block waiting for any analysis.
    * Returns `true` if the contributor's work is complete
    * or `false` if [computeFull] should be called to complete the work.
    */
   bool computeFast(DartCompletionRequest request);

   /**
    * Computes the complete set of [CompletionSuggestion]s based on
    * the given completion context.  The compilation unit and completion node
    * in the given completion context are resolved.
    * Returns `true` if the receiver modified the list of suggestions.
    */
   Future<bool> computeFull(DartCompletionRequest request);
 }

 /**
  * Manages code completion for a given Dart file completion request.
  */
 class DartCompletionManager extends CompletionManager {
   final SearchEngine searchEngine;
   final DartCompletionCache cache;
   List<DartCompletionContributor> contributors;
   CommonUsageComputer commonUsageComputer;

   DartCompletionManager(
       AnalysisContext context, this.searchEngine, Source source, this.cache,
       [this.contributors, this.commonUsageComputer])
       : super(context, source) {
     if (contributors == null) {
       contributors = [
         // LocalReferenceContributor before ImportedReferenceContributor
         // because local suggestions take precedence
         // and can hide other suggestions with the same name
         new LocalReferenceContributor(),
         new ImportedReferenceContributor(),
         new KeywordContributor(),
         new ArgListContributor(),
         new CombinatorContributor(),
         new PrefixedElementContributor(),
         new ImportUriContributor(),
       ];
     }
     if (commonUsageComputer == null) {
       commonUsageComputer = new CommonUsageComputer();
     }
   }

   /**
    * Create a new initialized Dart source completion manager
    */
   factory DartCompletionManager.create(
       AnalysisContext context, SearchEngine searchEngine, Source source) {
     return new DartCompletionManager(context, searchEngine, source,
         new DartCompletionCache(context, source));
   }

   @override
   Future<bool> computeCache() {
     return waitForAnalysis().then((CompilationUnit unit) {
       if (unit != null && !cache.isImportInfoCached(unit)) {
         return cache.computeImportInfo(unit, searchEngine, true);
       } else {
         return new Future.value(false);
       }
     });
   }

   /**
    * Compute suggestions based upon cached information only
    * then send an initial response to the client.
    * Return a list of contributors for which [computeFull] should be called
    */
   List<DartCompletionContributor> computeFast(
       DartCompletionRequest request, CompletionPerformance performance) {
     bool isKeywordOrIdentifier(Token token) =>
         token.type == TokenType.KEYWORD || token.type == TokenType.IDENTIFIER;

     return performance.logElapseTime('computeFast', () {
       CompilationUnit unit = context.parseCompilationUnit(source);
       request.unit = unit;
       request.target = new CompletionTarget.forOffset(unit, request.offset);
       request.replacementOffset = request.offset;
       request.replacementLength = 0;
       if (request.offset < 0 || request.offset > unit.end) {
         sendResults(request, true);
         return [];
       }

       var entity = request.target.entity;
       Token token = entity is AstNode ? entity.beginToken : entity;
       if (token != null && request.offset < token.offset) {
         token = token.previous;
       }
       if (token != null) {
         if (request.offset == token.offset && !isKeywordOrIdentifier(token)) {
           // If the insertion point is at the beginning of the current token
           // and the current token is not an identifier
           // then check the previous token to see if it should be replaced
           token = token.previous;
         }
         if (token != null && isKeywordOrIdentifier(token)) {
           if (token.offset <= request.offset && request.offset <= token.end) {
             request.replacementOffset = token.offset;
             request.replacementLength = token.length;
           }
         }
       }

       List<DartCompletionContributor> todo = new List.from(contributors);
       todo.removeWhere((DartCompletionContributor c) {
         return performance.logElapseTime('computeFast ${c.runtimeType}', () {
           return c.computeFast(request);
         });
       });
       commonUsageComputer.computeFast(request);
       sendResults(request, todo.isEmpty);
       return todo;
     });
   }

   /**
    * If there is remaining work to be done, then wait for the unit to be
    * resolved and request that each remaining contributor finish their work.
    * Return a [Future] that completes when the last notification has been sent.
    */
   Future computeFull(DartCompletionRequest request,
       CompletionPerformance performance, List<DartCompletionContributor> todo) {
     performance.logStartTime('waitForAnalysis');
     return waitForAnalysis().then((CompilationUnit unit) {
       if (controller.isClosed) {
         return;
       }
       performance.logElapseTime('waitForAnalysis');
       if (unit == null) {
         sendResults(request, true);
         return;
       }
       performance.logElapseTime('computeFull', () {
         request.unit = unit;
         // TODO(paulberry): Do we need to invoke _ReplacementOffsetBuilder
         // again?
         request.target = new CompletionTarget.forOffset(unit, request.offset);
         int count = todo.length;
         todo.forEach((DartCompletionContributor c) {
           String name = c.runtimeType.toString();
           String completeTag = 'computeFull $name complete';
           performance.logStartTime(completeTag);
           performance.logElapseTime('computeFull $name', () {
             c.computeFull(request).then((bool changed) {
               performance.logElapseTime(completeTag);
               bool last = --count == 0;
               if (changed || last) {
                 commonUsageComputer.computeFull(request);
                 sendResults(request, last);
               }
             });
           });
         });
       });
     });
   }

   @override
   void computeSuggestions(CompletionRequest completionRequest) {
     DartCompletionRequest request =
         new DartCompletionRequest.from(completionRequest, cache);
     CompletionPerformance performance = new CompletionPerformance();
     performance.logElapseTime('compute', () {
       List<DartCompletionContributor> todo = computeFast(request, performance);
       if (!todo.isEmpty) {
         computeFull(request, performance, todo);
       }
     });
   }

   /**
    * Send the current list of suggestions to the client.
    */
   void sendResults(DartCompletionRequest request, bool last) {
     if (controller == null || controller.isClosed) {
       return;
     }
     controller.add(new CompletionResultImpl(request.replacementOffset,
         request.replacementLength, request.suggestions, last));
     if (last) {
       controller.close();
     }
   }

   /**
    * Return a future that either (a) completes with the resolved compilation
    * unit when analysis is complete, or (b) completes with null if the
    * compilation unit is never going to be resolved.
    */
   Future<CompilationUnit> waitForAnalysis() {
     List<Source> libraries = context.getLibrariesContaining(source);
     assert(libraries != null);
     if (libraries.length == 0) {
       return new Future.value(null);
     }
     Source libSource = libraries[0];
     assert(libSource != null);
     return context
         .computeResolvedCompilationUnitAsync(source, libSource)
         .catchError((_) {
       // This source file is not scheduled for analysis, so a resolved
       // compilation unit is never going to get computed.
       return null;
     }, test: (e) => e is AnalysisNotScheduledError);
   }
 }

 /**
  * The context in which the completion is requested.
  */
 class DartCompletionRequest extends CompletionRequestImpl {
   /**
    * Cached information from a prior code completion operation.
    */
   final DartCompletionCache cache;

   /**
    * The compilation unit in which the completion was requested. This unit
    * may or may not be resolved when [DartCompletionContributor.computeFast]
    * is called but is resolved when [DartCompletionContributor.computeFull].
    */
   CompilationUnit unit;

   /**
    * The completion target.  This determines what part of the parse tree
    * will receive the newly inserted text.
    */
   CompletionTarget target;

   /**
    * Information about the types of suggestions that should be included.
    */
   OpType _optype;

   /**
    * The offset of the start of the text to be replaced.
    * This will be different than the offset used to request the completion
    * suggestions if there was a portion of an identifier before the original
    * offset. In particular, the replacementOffset will be the offset of the
    * beginning of said identifier.
    */
   int replacementOffset;

   /**
    * The length of the text to be replaced if the remainder of the identifier
    * containing the cursor is to be replaced when the suggestion is applied
    * (that is, the number of characters in the existing identifier).
    */
   int replacementLength;

   /**
    * The list of suggestions to be sent to the client.
    */
   final List<CompletionSuggestion> _suggestions = <CompletionSuggestion>[];

   /**
    * The set of completions used to prevent duplicates
    */
   final Set<String> _completions = new Set<String>();

   DartCompletionRequest(AnalysisServer server, AnalysisContext context,
       Source source, int offset, this.cache)
       : super(server, context, source, offset);

   factory DartCompletionRequest.from(CompletionRequestImpl request,
       DartCompletionCache cache) => new DartCompletionRequest(
       request.server, request.context, request.source, request.offset, cache);

   /**
    * Return the original text from the [replacementOffset] to the [offset]
    * that can be used to filter the suggestions on the server side.
    */
   String get filterText {
     return context.getContents(source).data.substring(
         replacementOffset, offset);
   }

   /**
    * Information about the types of suggestions that should be included.
    * The [target] must be set first.
    */
   OpType get optype {
     if (_optype == null) {
       _optype = new OpType.forCompletion(target, offset);
     }
     return _optype;
   }

   /**
    * The search engine for use when building suggestions.
    */
   SearchEngine get searchEngine => server.searchEngine;

   /**
    * The list of suggestions to be sent to the client.
    */
   Iterable<CompletionSuggestion> get suggestions => _suggestions;

   /**
    * Add the given suggestion to the list that is returned to the client as long
    * as a suggestion with an identical completion has not already been added.
    */
   void addSuggestion(CompletionSuggestion suggestion) {
     if (_completions.add(suggestion.completion)) {
       _suggestions.add(suggestion);
     }
   }

   /**
    * Convert all [CompletionSuggestionKind.INVOCATION] suggestions
    * to [CompletionSuggestionKind.IDENTIFIER] suggestions.
    */
   void convertInvocationsToIdentifiers() {
     for (int index = _suggestions.length - 1; index >= 0; --index) {
       CompletionSuggestion suggestion = _suggestions[index];
       if (suggestion.kind == CompletionSuggestionKind.INVOCATION) {
         // Create a copy rather than just modifying the existing suggestion
         // because [DartCompletionCache] may be caching that suggestion
         // for future completion requests
         _suggestions[index] = new CompletionSuggestion(
             CompletionSuggestionKind.IDENTIFIER, suggestion.relevance,
             suggestion.completion, suggestion.selectionOffset,
             suggestion.selectionLength, suggestion.isDeprecated,
             suggestion.isPotential,
             declaringType: suggestion.declaringType,
             parameterNames: suggestion.parameterNames,
             parameterTypes: suggestion.parameterTypes,
             requiredParameterCount: suggestion.requiredParameterCount,
             hasNamedParameters: suggestion.hasNamedParameters,
             returnType: suggestion.returnType,
             element: suggestion.element);
       }
     }
   }
 }
	// Copyright (c) 2014, 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.

	library services.completion.dart;

	import 'dart:async';

	import 'package:analysis_server/completion/completion_core.dart'
	show CompletionRequest;
	import 'package:analysis_server/src/analysis_server.dart';
	import 'package:analysis_server/src/protocol.dart';
	import 'package:analysis_server/src/services/completion/arglist_contributor.dart';
	import 'package:analysis_server/src/services/completion/combinator_contributor.dart';
	import 'package:analysis_server/src/services/completion/common_usage_computer.dart';
	import 'package:analysis_server/src/services/completion/completion_manager.dart';
	import 'package:analysis_server/src/services/completion/completion_target.dart';
	import 'package:analysis_server/src/services/completion/dart_completion_cache.dart';
	import 'package:analysis_server/src/services/completion/import_uri_contributor.dart';
	import 'package:analysis_server/src/services/completion/imported_reference_contributor.dart';
	import 'package:analysis_server/src/services/completion/keyword_contributor.dart';
	import 'package:analysis_server/src/services/completion/local_reference_contributor.dart';
	import 'package:analysis_server/src/services/completion/optype.dart';
	import 'package:analysis_server/src/services/completion/prefixed_element_contributor.dart';
	import 'package:analysis_server/src/services/search/search_engine.dart';
	import 'package:analyzer/src/generated/ast.dart';
	import 'package:analyzer/src/generated/engine.dart';
	import 'package:analyzer/src/generated/scanner.dart';
	import 'package:analyzer/src/generated/source.dart';

	const int DART_RELEVANCE_COMMON_USAGE = 1200;
	const int DART_RELEVANCE_DEFAULT = 1000;
	const int DART_RELEVANCE_HIGH = 2000;
	const int DART_RELEVANCE_INHERITED_ACCESSOR = 1057;
	const int DART_RELEVANCE_INHERITED_FIELD = 1058;
	const int DART_RELEVANCE_INHERITED_METHOD = 1057;
	const int DART_RELEVANCE_KEYWORD = 1055;
	const int DART_RELEVANCE_LOCAL_ACCESSOR = 1057;
	const int DART_RELEVANCE_LOCAL_FIELD = 1058;
	const int DART_RELEVANCE_LOCAL_FUNCTION = 1056;
	const int DART_RELEVANCE_LOCAL_METHOD = 1057;
	const int DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE = 1056;
	const int DART_RELEVANCE_LOCAL_VARIABLE = 1059;
	const int DART_RELEVANCE_LOW = 500;
	const int DART_RELEVANCE_NAMED_PARAMETER = 1060;
	const int DART_RELEVANCE_PARAMETER = 1059;

	/**
	* The base class for contributing code completion suggestions.
	*/
	abstract class DartCompletionContributor {
	/**
	* Computes the initial set of [CompletionSuggestion]s based on
	* the given completion context. The compilation unit and completion node
	* in the given completion context may not be resolved.
	* This method should execute quickly and not block waiting for any analysis.
	* Returns `true` if the contributor's work is complete
	* or `false` if [computeFull] should be called to complete the work.
	*/
	bool computeFast(DartCompletionRequest request);

	/**
	* Computes the complete set of [CompletionSuggestion]s based on
	* the given completion context. The compilation unit and completion node
	* in the given completion context are resolved.
	* Returns `true` if the receiver modified the list of suggestions.
	*/
	Future<bool> computeFull(DartCompletionRequest request);
	}

	/**
	* Manages code completion for a given Dart file completion request.
	*/
	class DartCompletionManager extends CompletionManager {
	final SearchEngine searchEngine;
	final DartCompletionCache cache;
	List<DartCompletionContributor> contributors;
	CommonUsageComputer commonUsageComputer;

	DartCompletionManager(
	AnalysisContext context, this.searchEngine, Source source, this.cache,
	[this.contributors, this.commonUsageComputer])
	: super(context, source) {
	if (contributors == null) {
	contributors = [
	// LocalReferenceContributor before ImportedReferenceContributor
	// because local suggestions take precedence
	// and can hide other suggestions with the same name
	new LocalReferenceContributor(),
	new ImportedReferenceContributor(),
	new KeywordContributor(),
	new ArgListContributor(),
	new CombinatorContributor(),
	new PrefixedElementContributor(),
	new ImportUriContributor(),
	];
	}
	if (commonUsageComputer == null) {
	commonUsageComputer = new CommonUsageComputer();
	}
	}

	/**
	* Create a new initialized Dart source completion manager
	*/
	factory DartCompletionManager.create(
	AnalysisContext context, SearchEngine searchEngine, Source source) {
	return new DartCompletionManager(context, searchEngine, source,
	new DartCompletionCache(context, source));
	}

	@override
	Future<bool> computeCache() {
	return waitForAnalysis().then((CompilationUnit unit) {
	if (unit != null && !cache.isImportInfoCached(unit)) {
	return cache.computeImportInfo(unit, searchEngine, true);
	} else {
	return new Future.value(false);
	}
	});
	}

	/**
	* Compute suggestions based upon cached information only
	* then send an initial response to the client.
	* Return a list of contributors for which [computeFull] should be called
	*/
	List<DartCompletionContributor> computeFast(
	DartCompletionRequest request, CompletionPerformance performance) {
	bool isKeywordOrIdentifier(Token token) =>
	token.type == TokenType.KEYWORD \|\| token.type == TokenType.IDENTIFIER;

	return performance.logElapseTime('computeFast', () {
	CompilationUnit unit = context.parseCompilationUnit(source);
	request.unit = unit;
	request.target = new CompletionTarget.forOffset(unit, request.offset);
	request.replacementOffset = request.offset;
	request.replacementLength = 0;
	if (request.offset < 0 \|\| request.offset > unit.end) {
	sendResults(request, true);
	return [];
	}

	var entity = request.target.entity;
	Token token = entity is AstNode ? entity.beginToken : entity;
	if (token != null && request.offset < token.offset) {
	token = token.previous;
	}
	if (token != null) {
	if (request.offset == token.offset && !isKeywordOrIdentifier(token)) {
	// If the insertion point is at the beginning of the current token
	// and the current token is not an identifier
	// then check the previous token to see if it should be replaced
	token = token.previous;
	}
	if (token != null && isKeywordOrIdentifier(token)) {
	if (token.offset <= request.offset && request.offset <= token.end) {
	request.replacementOffset = token.offset;
	request.replacementLength = token.length;
	}
	}
	}

	List<DartCompletionContributor> todo = new List.from(contributors);
	todo.removeWhere((DartCompletionContributor c) {
	return performance.logElapseTime('computeFast ${c.runtimeType}', () {
	return c.computeFast(request);
	});
	});
	commonUsageComputer.computeFast(request);
	sendResults(request, todo.isEmpty);
	return todo;
	});
	}

	/**
	* If there is remaining work to be done, then wait for the unit to be
	* resolved and request that each remaining contributor finish their work.
	* Return a [Future] that completes when the last notification has been sent.
	*/
	Future computeFull(DartCompletionRequest request,
	CompletionPerformance performance, List<DartCompletionContributor> todo) {
	performance.logStartTime('waitForAnalysis');
	return waitForAnalysis().then((CompilationUnit unit) {
	if (controller.isClosed) {
	return;
	}
	performance.logElapseTime('waitForAnalysis');
	if (unit == null) {
	sendResults(request, true);
	return;
	}
	performance.logElapseTime('computeFull', () {
	request.unit = unit;
	// TODO(paulberry): Do we need to invoke _ReplacementOffsetBuilder
	// again?
	request.target = new CompletionTarget.forOffset(unit, request.offset);
	int count = todo.length;
	todo.forEach((DartCompletionContributor c) {
	String name = c.runtimeType.toString();
	String completeTag = 'computeFull $name complete';
	performance.logStartTime(completeTag);
	performance.logElapseTime('computeFull $name', () {
	c.computeFull(request).then((bool changed) {
	performance.logElapseTime(completeTag);
	bool last = --count == 0;
	if (changed \|\| last) {
	commonUsageComputer.computeFull(request);
	sendResults(request, last);
	}
	});
	});
	});
	});
	});
	}

	@override
	void computeSuggestions(CompletionRequest completionRequest) {
	DartCompletionRequest request =
	new DartCompletionRequest.from(completionRequest, cache);
	CompletionPerformance performance = new CompletionPerformance();
	performance.logElapseTime('compute', () {
	List<DartCompletionContributor> todo = computeFast(request, performance);
	if (!todo.isEmpty) {
	computeFull(request, performance, todo);
	}
	});
	}

	/**
	* Send the current list of suggestions to the client.
	*/
	void sendResults(DartCompletionRequest request, bool last) {
	if (controller == null \|\| controller.isClosed) {
	return;
	}
	controller.add(new CompletionResultImpl(request.replacementOffset,
	request.replacementLength, request.suggestions, last));
	if (last) {
	controller.close();
	}
	}

	/**
	* Return a future that either (a) completes with the resolved compilation
	* unit when analysis is complete, or (b) completes with null if the
	* compilation unit is never going to be resolved.
	*/
	Future<CompilationUnit> waitForAnalysis() {
	List<Source> libraries = context.getLibrariesContaining(source);
	assert(libraries != null);
	if (libraries.length == 0) {
	return new Future.value(null);
	}
	Source libSource = libraries[0];
	assert(libSource != null);
	return context
	.computeResolvedCompilationUnitAsync(source, libSource)
	.catchError((_) {
	// This source file is not scheduled for analysis, so a resolved
	// compilation unit is never going to get computed.
	return null;
	}, test: (e) => e is AnalysisNotScheduledError);
	}
	}

	/**
	* The context in which the completion is requested.
	*/
	class DartCompletionRequest extends CompletionRequestImpl {
	/**
	* Cached information from a prior code completion operation.
	*/
	final DartCompletionCache cache;

	/**
	* The compilation unit in which the completion was requested. This unit
	* may or may not be resolved when [DartCompletionContributor.computeFast]
	* is called but is resolved when [DartCompletionContributor.computeFull].
	*/
	CompilationUnit unit;

	/**
	* The completion target. This determines what part of the parse tree
	* will receive the newly inserted text.
	*/
	CompletionTarget target;

	/**
	* Information about the types of suggestions that should be included.
	*/
	OpType _optype;

	/**
	* The offset of the start of the text to be replaced.
	* This will be different than the offset used to request the completion
	* suggestions if there was a portion of an identifier before the original
	* offset. In particular, the replacementOffset will be the offset of the
	* beginning of said identifier.
	*/
	int replacementOffset;

	/**
	* The length of the text to be replaced if the remainder of the identifier
	* containing the cursor is to be replaced when the suggestion is applied
	* (that is, the number of characters in the existing identifier).
	*/
	int replacementLength;

	/**
	* The list of suggestions to be sent to the client.
	*/
	final List<CompletionSuggestion> _suggestions = <CompletionSuggestion>[];

	/**
	* The set of completions used to prevent duplicates
	*/
	final Set<String> _completions = new Set<String>();

	DartCompletionRequest(AnalysisServer server, AnalysisContext context,
	Source source, int offset, this.cache)
	: super(server, context, source, offset);

	factory DartCompletionRequest.from(CompletionRequestImpl request,
	DartCompletionCache cache) => new DartCompletionRequest(
	request.server, request.context, request.source, request.offset, cache);

	/**
	* Return the original text from the [replacementOffset] to the [offset]
	* that can be used to filter the suggestions on the server side.
	*/
	String get filterText {
	return context.getContents(source).data.substring(
	replacementOffset, offset);
	}

	/**
	* Information about the types of suggestions that should be included.
	* The [target] must be set first.
	*/
	OpType get optype {
	if (_optype == null) {
	_optype = new OpType.forCompletion(target, offset);
	}
	return _optype;
	}

	/**
	* The search engine for use when building suggestions.
	*/
	SearchEngine get searchEngine => server.searchEngine;

	/**
	* The list of suggestions to be sent to the client.
	*/
	Iterable<CompletionSuggestion> get suggestions => _suggestions;

	/**
	* Add the given suggestion to the list that is returned to the client as long
	* as a suggestion with an identical completion has not already been added.
	*/
	void addSuggestion(CompletionSuggestion suggestion) {
	if (_completions.add(suggestion.completion)) {
	_suggestions.add(suggestion);
	}
	}

	/**
	* Convert all [CompletionSuggestionKind.INVOCATION] suggestions
	* to [CompletionSuggestionKind.IDENTIFIER] suggestions.
	*/
	void convertInvocationsToIdentifiers() {
	for (int index = _suggestions.length - 1; index >= 0; --index) {
	CompletionSuggestion suggestion = _suggestions[index];
	if (suggestion.kind == CompletionSuggestionKind.INVOCATION) {
	// Create a copy rather than just modifying the existing suggestion
	// because [DartCompletionCache] may be caching that suggestion
	// for future completion requests
	_suggestions[index] = new CompletionSuggestion(
	CompletionSuggestionKind.IDENTIFIER, suggestion.relevance,
	suggestion.completion, suggestion.selectionOffset,
	suggestion.selectionLength, suggestion.isDeprecated,
	suggestion.isPotential,
	declaringType: suggestion.declaringType,
	parameterNames: suggestion.parameterNames,
	parameterTypes: suggestion.parameterTypes,
	requiredParameterCount: suggestion.requiredParameterCount,
	hasNamedParameters: suggestion.hasNamedParameters,
	returnType: suggestion.returnType,
	element: suggestion.element);
	}
	}
	}
	}