blob: 59739f33469d6d3a0ee89daad59b413feca1e967 [file] [log] [blame]
// 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/dart/abstract_producer.dart';
import 'package:analysis_server/src/services/correction/fix.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
class AddAsync extends CorrectionProducer {
/// A flag indicating whether this producer is producing a fix in the case
/// where a function is missing a return at the end.
final bool isForMissingReturn;
/// Initialize a newly created producer.
AddAsync(this.isForMissingReturn);
@override
FixKind get fixKind => DartFixKind.ADD_ASYNC;
@override
Future<void> compute(ChangeBuilder builder) async {
if (isForMissingReturn) {
var parent = node.parent;
DartType returnType;
FunctionBody body;
if (parent is FunctionDeclaration) {
returnType = parent.returnType.type;
body = parent.functionExpression.body;
} else if (parent is MethodDeclaration) {
returnType = parent.returnType.type;
body = parent.body;
}
if (body == null) {
return;
}
if (_isFutureVoid(returnType) && _hasNoReturns(body)) {
await builder.addDartFileEdit(file, (builder) {
builder.addSimpleInsertion(body.offset, 'async ');
});
}
} else {
var body = node.thisOrAncestorOfType<FunctionBody>();
if (body != null && body.keyword == null) {
var typeProvider = this.typeProvider;
await builder.addDartFileEdit(file, (builder) {
builder.convertFunctionFromSyncToAsync(body, typeProvider);
});
}
}
}
/// Return `true` if there are no return statements in the given function
/// [body].
bool _hasNoReturns(FunctionBody body) {
var finder = _ReturnFinder();
body.accept(finder);
return !finder.foundReturn;
}
/// Return `true` if the [type] is `Future<void>`.
bool _isFutureVoid(DartType type) {
if (type is InterfaceType && type.isDartAsyncFuture) {
return type.typeArguments[0].isVoid;
}
return false;
}
/// Return an instance of this class. Used as a tear-off in `FixProcessor`.
static AddAsync missingReturn() => AddAsync(true);
/// Return an instance of this class. Used as a tear-off in `FixProcessor`.
static AddAsync newInstance() => AddAsync(false);
}
/// An AST visitor used to find return statements in function bodies.
class _ReturnFinder extends RecursiveAstVisitor<void> {
/// A flag indicating whether a return statement was visited.
bool foundReturn = false;
/// Initialize a newly created visitor.
_ReturnFinder();
@override
void visitFunctionExpression(FunctionExpression node) {
// Return statements within closures aren't counted.
}
@override
void visitReturnStatement(ReturnStatement node) {
foundReturn = true;
}
}