rework ArgListContributor to use new task model

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

Index: pkg/analysis_server/lib/src/services/completion/arglist_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/arglist_contributor.dart b/pkg/analysis_server/lib/src/services/completion/arglist_contributor.dart
deleted file mode 100644
index 69d00446ad64a5f845b87af36b10edb3c116fac2..0000000000000000000000000000000000000000
--- a/pkg/analysis_server/lib/src/services/completion/arglist_contributor.dart
+++ /dev/null
@@ -1,427 +0,0 @@
-// 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.contributor.dart.arglist;
-
-import 'dart:async';
-
-import 'package:analysis_server/src/protocol_server.dart'
-    hide Element, ElementKind;
-import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
-import 'package:analysis_server/src/services/completion/local_declaration_visitor.dart';
-import 'package:analyzer/src/generated/ast.dart';
-import 'package:analyzer/src/generated/element.dart';
-import 'package:analyzer/src/generated/scanner.dart';
-import 'package:analyzer/src/generated/utilities_dart.dart';
-
-void _addNamedParameterSuggestion(
-    DartCompletionRequest request, List<String> namedArgs, String name) {
-  if (name != null && name.length > 0 && !namedArgs.contains(name)) {
-    request.addSuggestion(new CompletionSuggestion(
-        CompletionSuggestionKind.NAMED_ARGUMENT,
-        DART_RELEVANCE_NAMED_PARAMETER,
-        '$name: ',
-        name.length + 2,
-        0,
-        false,
-        false));
-  }
-}
-
-/**
- * Determine the number of arguments.
- */
-int _argCount(DartCompletionRequest request) {
-  AstNode node = request.target.containingNode;
-  if (node is ArgumentList) {
-    return node.arguments.length;
-  }
-  return 0;
-}
-
-/**
- * Determine if the completion target is at the end of the list of arguments.
- */
-bool _isAppendingToArgList(DartCompletionRequest request) {
-  AstNode node = request.target.containingNode;
-  if (node is ArgumentList) {
-    var entity = request.target.entity;
-    if (entity == node.rightParenthesis) {
-      return true;
-    }
-    if (node.arguments.length > 0 && node.arguments.last == entity) {
-      return entity is SimpleIdentifier;
-    }
-  }
-  return false;
-}
-
-/**
- * Determine if the completion target is an emtpy argument list.
- */
-bool _isEmptyArgList(DartCompletionRequest request) {
-  AstNode node = request.target.containingNode;
-  return node is ArgumentList &&
-      node.leftParenthesis.next == node.rightParenthesis;
-}
-
-/**
- * Return a collection of currently specified named arguments
- */
-Iterable<String> _namedArgs(DartCompletionRequest request) {
-  AstNode node = request.target.containingNode;
-  List<String> namedArgs = new List<String>();
-  if (node is ArgumentList) {
-    for (Expression arg in node.arguments) {
-      if (arg is NamedExpression) {
-        namedArgs.add(arg.name.label.name);
-      }
-    }
-  }
-  return namedArgs;
-}
-
-/**
- * A contributor for calculating `completion.getSuggestions` request results
- * when the cursor position is inside the arguments to a method call.
- */
-class ArgListContributor extends DartCompletionContributor {
-  _ArgSuggestionBuilder builder;
-
-  @override
-  bool computeFast(DartCompletionRequest request) {
-    builder =
-        request.target.containingNode.accept(new _ArgListAstVisitor(request));
-    return builder == null;
-  }
-
-  @override
-  Future<bool> computeFull(DartCompletionRequest request) {
-    if (builder != null) {
-      return builder.compute(request.target.containingNode);
-    }
-    return new Future.value(false);
-  }
-}
-
-/**
- * A visitor for determining whether an argument list suggestion is needed
- * and instantiating the builder to create the suggestion.
- */
-class _ArgListAstVisitor extends GeneralizingAstVisitor<_ArgSuggestionBuilder> {
-  final DartCompletionRequest request;
-
-  _ArgListAstVisitor(this.request);
-
-  @override
-  _ArgSuggestionBuilder visitArgumentList(ArgumentList node) {
-    Token leftParen = node.leftParenthesis;
-    if (leftParen != null && request.offset > leftParen.offset) {
-      AstNode parent = node.parent;
-      if (parent is MethodInvocation) {
-        SimpleIdentifier selector = parent.methodName;
-        if (selector != null) {
-          String name = selector.name;
-          if (name != null && name.length > 0) {
-            if (parent.operator == null) {
-              /*
-               * If a local declaration is found, then return null
-               * indicating that suggestions were added
-               * and no further action is necessary
-               */
-              if (new _LocalArgSuggestionBuilder(request, request.offset, name)
-                  .visit(node)) {
-                return null;
-              }
-            } else {
-              // determine target
-            }
-            return new _ArgSuggestionBuilder(request, name);
-          }
-        }
-      }
-      String constructorName;
-      if (parent is Annotation && parent.name != null) {
-        constructorName = parent.name.toSource();
-      }
-      if (parent is InstanceCreationExpression &&
-          parent.constructorName != null) {
-        constructorName = parent.constructorName.toSource();
-      }
-      if (constructorName != null && constructorName.length > 0) {
-        if (new _LocalArgSuggestionBuilder(
-            request, request.offset, constructorName).visit(node)) {
-          return null;
-        }
-        return new _ArgSuggestionBuilder(request, constructorName);
-      }
-    }
-    return null;
-  }
-
-  @override
-  _ArgSuggestionBuilder visitNode(AstNode node) {
-    return null;
-  }
-}
-
-/**
- * A [_ArgSuggestionBuilder] determines which method or function is being
- * invoked, then builds the argument list suggestion.
- * This operation is instantiated during `computeFast`
- * and calculates the suggestions during `computeFull`.
- */
-class _ArgSuggestionBuilder {
-  final DartCompletionRequest request;
-  final String methodName;
-
-  _ArgSuggestionBuilder(this.request, this.methodName);
-
-  Future<bool> compute(ArgumentList node) {
-    AstNode parent = node.parent;
-    if (parent is MethodInvocation) {
-      SimpleIdentifier methodName = parent.methodName;
-      if (methodName != null) {
-        Element methodElem = methodName.bestElement;
-        if (methodElem is ExecutableElement) {
-          _addSuggestions(methodElem.parameters);
-        }
-      }
-    }
-    if (parent is InstanceCreationExpression) {
-      ConstructorName constructorName = parent.constructorName;
-      if (constructorName != null) {
-        ConstructorElement element = constructorName.staticElement;
-        if (element is ExecutableElement) {
-          _addSuggestions(element.parameters);
-        }
-      }
-    }
-    if (parent is Annotation) {
-      Element element = parent.element;
-      if (element is ExecutableElement) {
-        _addSuggestions(element.parameters);
-      }
-    }
-    return new Future.value(false);
-  }
-
-  void _addArgListSuggestion(Iterable<ParameterElement> requiredParam) {
-    StringBuffer completion = new StringBuffer('(');
-    List<String> paramNames = new List<String>();
-    List<String> paramTypes = new List<String>();
-    for (ParameterElement param in requiredParam) {
-      String name = param.name;
-      if (name != null && name.length > 0) {
-        if (completion.length > 1) {
-          completion.write(', ');
-        }
-        completion.write(name);
-        paramNames.add(name);
-        paramTypes.add(_getParamType(param));
-      }
-    }
-    completion.write(')');
-    CompletionSuggestion suggestion = new CompletionSuggestion(
-        CompletionSuggestionKind.ARGUMENT_LIST,
-        DART_RELEVANCE_HIGH,
-        completion.toString(),
-        completion.length,
-        0,
-        false,
-        false);
-    suggestion.parameterNames = paramNames;
-    suggestion.parameterTypes = paramTypes;
-    request.addSuggestion(suggestion);
-  }
-
-  void _addDefaultParamSuggestions(Iterable<ParameterElement> parameters) {
-    Iterable<String> namedArgs = _namedArgs(request);
-    for (ParameterElement param in parameters) {
-      if (param.parameterKind == ParameterKind.NAMED) {
-        _addNamedParameterSuggestion(request, namedArgs, param.name);
-      }
-    }
-  }
-
-  void _addSuggestions(Iterable<ParameterElement> parameters) {
-    if (parameters == null || parameters.length == 0) {
-      return;
-    }
-    Iterable<ParameterElement> requiredParam = parameters.where(
-        (ParameterElement p) => p.parameterKind == ParameterKind.REQUIRED);
-    int requiredCount = requiredParam.length;
-    if (requiredCount > 0 && _isEmptyArgList(request)) {
-      _addArgListSuggestion(requiredParam);
-      return;
-    }
-    if (_isAppendingToArgList(request)) {
-      if (requiredCount == 0 || requiredCount < _argCount(request)) {
-        _addDefaultParamSuggestions(parameters);
-      }
-    }
-  }
-
-  String _getParamType(ParameterElement param) {
-    DartType type = param.type;
-    if (type != null) {
-      return type.displayName;
-    }
-    return 'dynamic';
-  }
-}
-
-/**
- * [_LocalArgSuggestionBuilder] visits an [AstNode] and its parent recursively
- * looking for a matching declaration. If found, it adds the appropriate
- * suggestions and sets finished to `true`.
- */
-class _LocalArgSuggestionBuilder extends LocalDeclarationVisitor {
-  final DartCompletionRequest request;
-  final String name;
-
-  _LocalArgSuggestionBuilder(this.request, int offset, this.name)
-      : super(offset);
-
-  @override
-  void declaredClass(ClassDeclaration declaration) {
-    String className = null;
-    if (declaration.name != null) {
-      className = declaration.name.name;
-    }
-    if (className != null && className.length > 0) {
-      for (ClassMember member in declaration.members) {
-        if (member is ConstructorDeclaration) {
-          String selector = className;
-          if (member.name != null) {
-            selector = '$selector.${member.name.name}';
-          }
-          if (selector == name) {
-            _addSuggestions(member.parameters);
-            finished();
-          }
-        }
-      }
-    }
-  }
-
-  @override
-  void declaredClassTypeAlias(ClassTypeAlias declaration) {}
-
-  @override
-  void declaredField(FieldDeclaration fieldDecl, VariableDeclaration varDecl) {}
-
-  @override
-  void declaredFunction(FunctionDeclaration declaration) {
-    SimpleIdentifier selector = declaration.name;
-    if (selector != null && name == selector.name) {
-      _addSuggestions(declaration.functionExpression.parameters);
-      finished();
-    }
-  }
-
-  @override
-  void declaredFunctionTypeAlias(FunctionTypeAlias declaration) {}
-
-  @override
-  void declaredLabel(Label label, bool isCaseLabel) {}
-
-  @override
-  void declaredLocalVar(SimpleIdentifier name, TypeName type) {}
-
-  @override
-  void declaredMethod(MethodDeclaration declaration) {
-    SimpleIdentifier selector = declaration.name;
-    if (selector != null && name == selector.name) {
-      _addSuggestions(declaration.parameters);
-      finished();
-    }
-  }
-
-  @override
-  void declaredParam(SimpleIdentifier name, TypeName type) {}
-
-  @override
-  void declaredTopLevelVar(
-      VariableDeclarationList varList, VariableDeclaration varDecl) {}
-
-  void _addArgListSuggestion(Iterable<FormalParameter> requiredParam) {
-    StringBuffer completion = new StringBuffer('(');
-    List<String> paramNames = new List<String>();
-    List<String> paramTypes = new List<String>();
-    for (FormalParameter param in requiredParam) {
-      SimpleIdentifier paramId = param.identifier;
-      if (paramId != null) {
-        String name = paramId.name;
-        if (name != null && name.length > 0) {
-          if (completion.length > 1) {
-            completion.write(', ');
-          }
-          completion.write(name);
-          paramNames.add(name);
-          paramTypes.add(_getParamType(param));
-        }
-      }
-    }
-    completion.write(')');
-    CompletionSuggestion suggestion = new CompletionSuggestion(
-        CompletionSuggestionKind.ARGUMENT_LIST,
-        DART_RELEVANCE_HIGH,
-        completion.toString(),
-        completion.length,
-        0,
-        false,
-        false);
-    suggestion.parameterNames = paramNames;
-    suggestion.parameterTypes = paramTypes;
-    request.addSuggestion(suggestion);
-  }
-
-  void _addDefaultParamSuggestions(FormalParameterList parameters) {
-    Iterable<String> namedArgs = _namedArgs(request);
-    for (FormalParameter param in parameters.parameters) {
-      if (param.kind == ParameterKind.NAMED) {
-        SimpleIdentifier paramId = param.identifier;
-        if (paramId != null) {
-          _addNamedParameterSuggestion(request, namedArgs, paramId.name);
-        }
-      }
-    }
-  }
-
-  void _addSuggestions(FormalParameterList parameters) {
-    if (parameters == null || parameters.parameters.length == 0) {
-      return;
-    }
-    Iterable<FormalParameter> requiredParam = parameters.parameters
-        .where((FormalParameter p) => p.kind == ParameterKind.REQUIRED);
-    int requiredCount = requiredParam.length;
-    if (requiredCount > 0 && _isEmptyArgList(request)) {
-      _addArgListSuggestion(requiredParam);
-      return;
-    }
-    if (_isAppendingToArgList(request)) {
-      if (requiredCount == 0 || requiredCount < _argCount(request)) {
-        _addDefaultParamSuggestions(parameters);
-      }
-    }
-  }
-
-  String _getParamType(FormalParameter param) {
-    TypeName type;
-    if (param is SimpleFormalParameter) {
-      type = param.type;
-    }
-    if (type != null) {
-      Identifier id = type.name;
-      if (id != null) {
-        String name = id.name;
-        if (name != null && name.length > 0) {
-          return name;
-        }
-      }
-    }
-    return 'dynamic';
-  }
-}