Start converting assists to CorrectionProducer

Change-Id: Ie2d12ce8c15a75e8db71434d790c32a76a06b13e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151324
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>

Author: bwilkerson

pkg/analysis_server/lib/src/services/correction/assist_internal.dart

@@ -356,6 +356,8 @@ abstract class _AbstractCorrectionProducer {
   ResourceProvider get resourceProvider =>
       resolvedResult.session.resourceProvider;
 
+  int get selectionEnd => _context.selectionEnd;
+
   int get selectionLength => _context.selectionLength;
 
   int get selectionOffset => _context.selectionOffset;

pkg/analysis_server/lib/src/services/correction/dart/abstract_producer.dart

@@ -0,0 +1,69 @@
+// Copyright (c) 2020, 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 'package:analysis_server/src/protocol_server.dart';
+import 'package:analysis_server/src/services/correction/assist.dart';
+import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
+import 'package:analysis_server/src/services/correction/name_suggestion.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/src/dart/ast/utilities.dart';
+import 'package:analyzer_plugin/utilities/assist/assist.dart';
+import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
+
+class AssignToLocalVariable extends CorrectionProducer {
+  @override
+  AssistKind get assistKind => DartAssistKind.ASSIGN_TO_LOCAL_VARIABLE;
+
+  @override
+  Future<void> compute(DartChangeBuilder builder) async {
+    // prepare enclosing ExpressionStatement
+    ExpressionStatement expressionStatement;
+    // ignore: unnecessary_this
+    for (var node = this.node; node != null; node = node.parent) {
+      if (node is ExpressionStatement) {
+        expressionStatement = node;
+        break;
+      }
+      if (node is ArgumentList ||
+          node is AssignmentExpression ||
+          node is Statement ||
+          node is ThrowExpression) {
+        return;
+      }
+    }
+    if (expressionStatement == null) {
+      return;
+    }
+    // prepare expression
+    var expression = expressionStatement.expression;
+    var offset = expression.offset;
+    // prepare expression type
+    var type = expression.staticType;
+    if (type.isVoid) {
+      return;
+    }
+    // prepare excluded names
+    var excluded = <String>{};
+    var scopedNameFinder = ScopedNameFinder(offset);
+    expression.accept(scopedNameFinder);
+    excluded.addAll(scopedNameFinder.locals.keys.toSet());
+    var suggestions =
+        getVariableNameSuggestionsForExpression(type, expression, excluded);
+
+    if (suggestions.isNotEmpty) {
+      await builder.addFileEdit(file, (builder) {
+        builder.addInsertion(offset, (builder) {
+          builder.write('var ');
+          builder.addSimpleLinkedEdit('NAME', suggestions[0],
+              kind: LinkedEditSuggestionKind.VARIABLE,
+              suggestions: suggestions);
+          builder.write(' = ');
+        });
+      });
+    }
+  }
+
+  /// Return an instance of this class. Used as a tear-off in `AssistProcessor`.
+  static AssignToLocalVariable newInstance() => AssignToLocalVariable();
+}

pkg/analysis_server/lib/src/services/correction/dart/assign_to_local_variable.dart

@@ -0,0 +1,113 @@
+// Copyright (c) 2020, 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 'package:analysis_server/src/services/correction/assist.dart';
+import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
+import 'package:analyzer_plugin/utilities/assist/assist.dart';
+import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
+import 'package:analyzer_plugin/utilities/range_factory.dart';
+
+class ConvertClassToMixin extends CorrectionProducer {
+  @override
+  AssistKind get assistKind => DartAssistKind.CONVERT_CLASS_TO_MIXIN;
+
+  @override
+  Future<void> compute(DartChangeBuilder builder) async {
+    var classDeclaration = node.thisOrAncestorOfType<ClassDeclaration>();
+    if (classDeclaration == null) {
+      return;
+    }
+    if (selectionOffset > classDeclaration.name.end ||
+        selectionEnd < classDeclaration.classKeyword.offset) {
+      return;
+    }
+    if (classDeclaration.members
+        .any((member) => member is ConstructorDeclaration)) {
+      return;
+    }
+    var finder = _SuperclassReferenceFinder();
+    classDeclaration.accept(finder);
+    var referencedClasses = finder.referencedClasses;
+    var superclassConstraints = <InterfaceType>[];
+    var interfaces = <InterfaceType>[];
+
+    var classElement = classDeclaration.declaredElement;
+    for (var type in classElement.mixins) {
+      if (referencedClasses.contains(type.element)) {
+        superclassConstraints.add(type);
+      } else {
+        interfaces.add(type);
+      }
+    }
+    var extendsClause = classDeclaration.extendsClause;
+    if (extendsClause != null) {
+      if (referencedClasses.length > superclassConstraints.length) {
+        superclassConstraints.insert(0, classElement.supertype);
+      } else {
+        interfaces.insert(0, classElement.supertype);
+      }
+    }
+    interfaces.addAll(classElement.interfaces);
+
+    await builder.addFileEdit(file, (builder) {
+      builder.addReplacement(
+          range.startStart(
+              classDeclaration.abstractKeyword ?? classDeclaration.classKeyword,
+              classDeclaration.leftBracket), (builder) {
+        builder.write('mixin ');
+        builder.write(classDeclaration.name.name);
+        builder.writeTypeParameters(
+            classDeclaration.declaredElement.typeParameters);
+        builder.writeTypes(superclassConstraints, prefix: ' on ');
+        builder.writeTypes(interfaces, prefix: ' implements ');
+        builder.write(' ');
+      });
+    });
+  }
+
+  /// Return an instance of this class. Used as a tear-off in `AssistProcessor`.
+  static ConvertClassToMixin newInstance() => ConvertClassToMixin();
+}
+
+/// A visitor used to find all of the classes that define members referenced via
+/// `super`.
+class _SuperclassReferenceFinder extends RecursiveAstVisitor<void> {
+  final List<ClassElement> referencedClasses = <ClassElement>[];
+
+  _SuperclassReferenceFinder();
+
+  @override
+  void visitSuperExpression(SuperExpression node) {
+    var parent = node.parent;
+    if (parent is BinaryExpression) {
+      _addElement(parent.staticElement);
+    } else if (parent is IndexExpression) {
+      _addElement(parent.staticElement);
+    } else if (parent is MethodInvocation) {
+      _addIdentifier(parent.methodName);
+    } else if (parent is PrefixedIdentifier) {
+      _addIdentifier(parent.identifier);
+    } else if (parent is PropertyAccess) {
+      _addIdentifier(parent.propertyName);
+    }
+    return super.visitSuperExpression(node);
+  }
+
+  void _addElement(Element element) {
+    if (element is ExecutableElement) {
+      var enclosingElement = element.enclosingElement;
+      if (enclosingElement is ClassElement) {
+        referencedClasses.add(enclosingElement);
+      }
+    }
+  }
+
+  void _addIdentifier(SimpleIdentifier identifier) {
+    _addElement(identifier.staticElement);
+  }
+}

pkg/analysis_server/lib/src/services/correction/dart/convert_class_to_mixin.dart

@@ -0,0 +1,49 @@
+// Copyright (c) 2020, 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 'package:_fe_analyzer_shared/src/scanner/token.dart';
+import 'package:analysis_server/src/services/correction/assist.dart';
+import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer_plugin/utilities/assist/assist.dart';
+import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
+import 'package:analyzer_plugin/utilities/range_factory.dart';
+
+class ConvertDocumentationIntoBlock extends CorrectionProducer {
+  @override
+  AssistKind get assistKind => DartAssistKind.CONVERT_DOCUMENTATION_INTO_BLOCK;
+
+  @override
+  Future<void> compute(DartChangeBuilder builder) async {
+    var comment = node.thisOrAncestorOfType<Comment>();
+    if (comment == null || !comment.isDocumentation) {
+      return;
+    }
+    var tokens = comment.tokens;
+    if (tokens.isEmpty ||
+        tokens.any((Token token) =>
+            token is! DocumentationCommentToken ||
+            token.type != TokenType.SINGLE_LINE_COMMENT)) {
+      return;
+    }
+    var prefix = utils.getNodePrefix(comment);
+
+    await builder.addFileEdit(file, (DartFileEditBuilder builder) {
+      builder.addReplacement(range.node(comment), (DartEditBuilder builder) {
+        builder.writeln('/**');
+        for (var token in comment.tokens) {
+          builder.write(prefix);
+          builder.write(' *');
+          builder.writeln(token.lexeme.substring('///'.length));
+        }
+        builder.write(prefix);
+        builder.write(' */');
+      });
+    });
+  }
+
+  /// Return an instance of this class. Used as a tear-off in `AssistProcessor`.
+  static ConvertDocumentationIntoBlock newInstance() =>
+      ConvertDocumentationIntoBlock();
+}

pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_block.dart

@@ -0,0 +1,48 @@
+// Copyright (c) 2020, 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 'package:analysis_server/src/services/correction/assist.dart';
+import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer_plugin/utilities/assist/assist.dart';
+import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
+
+class ConvertIntoAsyncBody extends CorrectionProducer {
+  @override
+  AssistKind get assistKind => DartAssistKind.CONVERT_INTO_ASYNC_BODY;
+
+  @override
+  Future<void> compute(DartChangeBuilder builder) async {
+    var body = getEnclosingFunctionBody();
+    if (body == null ||
+        body is EmptyFunctionBody ||
+        body.isAsynchronous ||
+        body.isGenerator) {
+      return;
+    }
+
+    // Function bodies can be quite large, e.g. Flutter build() methods.
+    // It is surprising to see this Quick Assist deep in a function body.
+    if (body is BlockFunctionBody &&
+        selectionOffset > body.block.beginToken.end) {
+      return;
+    }
+    if (body is ExpressionFunctionBody &&
+        selectionOffset > body.beginToken.end) {
+      return;
+    }
+
+    var parent = body.parent;
+    if (parent is ConstructorDeclaration) {
+      return;
+    }
+
+    await builder.addFileEdit(file, (DartFileEditBuilder builder) {
+      builder.convertFunctionFromSyncToAsync(body, typeProvider);
+    });
+  }
+
+  /// Return an instance of this class. Used as a tear-off in `AssistProcessor`.
+  static ConvertIntoAsyncBody newInstance() => ConvertIntoAsyncBody();
+}

pkg/analysis_server/lib/src/services/correction/dart/convert_into_async_body.dart

@@ -0,0 +1,57 @@
+// Copyright (c) 2020, 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 'package:analysis_server/src/services/correction/assist.dart';
+import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer_plugin/utilities/assist/assist.dart';
+import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
+import 'package:analyzer_plugin/utilities/range_factory.dart';
+
+class ConvertIntoBlockBody extends CorrectionProducer {
+  @override
+  AssistKind get assistKind => DartAssistKind.CONVERT_INTO_BLOCK_BODY;
+
+  @override
+  Future<void> compute(DartChangeBuilder builder) async {
+    var body = getEnclosingFunctionBody();
+    // prepare expression body
+    if (body is! ExpressionFunctionBody || body.isGenerator) {
+      return;
+    }
+
+    var returnValue = (body as ExpressionFunctionBody).expression;
+
+    // Return expressions can be quite large, e.g. Flutter build() methods.
+    // It is surprising to see this Quick Assist deep in the function body.
+    if (selectionOffset >= returnValue.offset) {
+      return;
+    }
+
+    var returnValueType = returnValue.staticType;
+    var returnValueCode = utils.getNodeText(returnValue);
+    // prepare prefix
+    var prefix = utils.getNodePrefix(body.parent);
+    var indent = utils.getIndent(1);
+
+    await builder.addFileEdit(file, (DartFileEditBuilder builder) {
+      builder.addReplacement(range.node(body), (DartEditBuilder builder) {
+        if (body.isAsynchronous) {
+          builder.write('async ');
+        }
+        builder.write('{$eol$prefix$indent');
+        if (!returnValueType.isVoid && !returnValueType.isBottom) {
+          builder.write('return ');
+        }
+        builder.write(returnValueCode);
+        builder.write(';');
+        builder.selectHere();
+        builder.write('$eol$prefix}');
+      });
+    });
+  }
+
+  /// Return an instance of this class. Used as a tear-off in `AssistProcessor`.
+  static ConvertIntoBlockBody newInstance() => ConvertIntoBlockBody();
+}