first cut argument list completion suggestions

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

+// 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.computer.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/scanner.dart';
+
+/**
+ * A computer for calculating `completion.getSuggestions` request results
+ * for the import combinators show and hide.
+ */
+class ArgListComputer extends DartCompletionComputer {
+  _ArgListSuggestionBuilder builder;
+
+  @override
+  bool computeFast(DartCompletionRequest request) {
+    builder = request.node.accept(new _ArgListAstVisitor(request));
+    return builder == null;
+  }
+
+  @override
+  Future<bool> computeFull(DartCompletionRequest request) {
+    if (builder != null) {
+      return builder.compute(request.node);
+    }
+    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<_ArgListSuggestionBuilder> {
+  final DartCompletionRequest request;
+
+  _ArgListAstVisitor(this.request);
+
+  @override
+  _ArgListSuggestionBuilder 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.period == null) {
+              /*
+               * If a local declaration is found, then return null
+               * indicating that suggestions were added
+               * and no further action is necessary
+               */
+              if (node.accept(
+                  new _LocalDeclarationFinder(request, request.offset, name))) {
+                return null;
+              }
+            } else {
+              // determine target
+            }
+          }
+        }
+      }
+      return new _ArgListSuggestionBuilder(request);
+    }
+    return null;
+  }
+
+  @override
+  _ArgListSuggestionBuilder visitNode(AstNode node) {
+    return null;
+  }
+}
+
+/**
+ * A `_ArgListSuggestionBuilder` 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 _ArgListSuggestionBuilder {
+  final DartCompletionRequest request;
+
+  _ArgListSuggestionBuilder(this.request);
+
+  Future<bool> compute(ArgumentList node) {
+    return new Future.value(false);
+  }
+}
+
+/**
+ * `_LocalDeclarationFinder` 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 _LocalDeclarationFinder extends LocalDeclarationVisitor {
+
+  final DartCompletionRequest request;
+  final String name;
+
+  _LocalDeclarationFinder(this.request, int offset, this.name) : super(offset);
+
+  @override
+  void declaredClass(ClassDeclaration declaration) {
+  }
+
+  @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) {
+      finished = true;
+      _addArgListSuggestion(declaration.functionExpression.parameters);
+    }
+  }
+
+  @override
+  void declaredFunctionTypeAlias(FunctionTypeAlias declaration) {
+  }
+
+  @override
+  void declaredLabel(Label label) {
+  }
+
+  @override
+  void declaredLocalVar(SimpleIdentifier name, TypeName type) {
+  }
+
+  @override
+  void declaredMethod(MethodDeclaration declaration) {
+    SimpleIdentifier selector = declaration.name;
+    if (selector != null && name == selector.name) {
+      finished = true;
+      _addArgListSuggestion(declaration.parameters);
+    }
+  }
+
+  @override
+  void declaredParam(SimpleIdentifier name, TypeName type) {
+  }
+
+  @override
+  void declaredTopLevelVar(VariableDeclarationList varList,
+      VariableDeclaration varDecl) {
+  }
+
+  void _addArgListSuggestion(FormalParameterList parameters) {
+    if (parameters.parameters.length == 0) {
+      return;
+    }
+    StringBuffer completion = new StringBuffer('(');
+    List<String> paramNames = new List<String>();
+    List<String> paramTypes = new List<String>();
+    for (FormalParameter param in parameters.parameters) {
+      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,
+        CompletionRelevance.HIGH,
+        completion.toString(),
+        completion.length,
+        0,
+        false,
+        false);
+    suggestion.parameterNames = paramNames;
+    suggestion.parameterTypes = paramTypes;
+    request.suggestions.add(suggestion);
+  }
+
+  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';
+  }
+}