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aa609127e7
Extacted from #130101, dropped the `@_debugAssert` stuff from that PR so it's easier to review.
105 lines
3.7 KiB
Dart
105 lines
3.7 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'package:analyzer/dart/analysis/results.dart';
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import 'package:analyzer/dart/ast/ast.dart';
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import 'package:analyzer/dart/ast/visitor.dart';
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import 'package:analyzer/dart/element/element.dart';
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import 'package:analyzer/dart/element/type.dart';
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import 'package:path/path.dart' as path;
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import '../utils.dart';
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import 'analyze.dart';
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/// Verify that we use clampDouble instead of double.clamp for performance
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/// reasons.
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///
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/// See also:
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/// * https://github.com/flutter/flutter/pull/103559
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/// * https://github.com/flutter/flutter/issues/103917
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final AnalyzeRule noDoubleClamp = _NoDoubleClamp();
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class _NoDoubleClamp implements AnalyzeRule {
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final Map<ResolvedUnitResult, List<AstNode>> _errors = <ResolvedUnitResult, List<AstNode>>{};
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@override
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void applyTo(ResolvedUnitResult unit) {
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final _DoubleClampVisitor visitor = _DoubleClampVisitor();
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unit.unit.visitChildren(visitor);
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final List<AstNode> violationsInUnit = visitor.clampAccessNodes;
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if (violationsInUnit.isNotEmpty) {
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_errors.putIfAbsent(unit, () => <AstNode>[]).addAll(violationsInUnit);
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}
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}
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@override
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void reportViolations(String workingDirectory) {
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if (_errors.isEmpty) {
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return;
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}
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String locationInFile(ResolvedUnitResult unit, AstNode node) {
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return '${path.relative(path.relative(unit.path, from: workingDirectory))}:${unit.lineInfo.getLocation(node.offset).lineNumber}';
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}
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foundError(<String>[
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for (final MapEntry<ResolvedUnitResult, List<AstNode>> entry in _errors.entries)
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for (final AstNode node in entry.value)
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'${locationInFile(entry.key, node)}: ${node.parent}',
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'\n${bold}For performance reasons, we use a custom "clampDouble" function instead of using "double.clamp".$reset',
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]);
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}
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@override
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String toString() => 'No "double.clamp"';
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}
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class _DoubleClampVisitor extends RecursiveAstVisitor<void> {
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final List<AstNode> clampAccessNodes = <AstNode>[];
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// We don't care about directives or comments.
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@override
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void visitImportDirective(ImportDirective node) { }
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@override
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void visitExportDirective(ExportDirective node) { }
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@override
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void visitComment(Comment node) { }
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@override
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void visitSimpleIdentifier(SimpleIdentifier node) {
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if (node.name != 'clamp' || node.staticElement is! MethodElement) {
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return;
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}
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final bool isAllowed = switch (node.parent) {
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// PropertyAccess matches num.clamp in tear-off form. Always prefer
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// doubleClamp over tear-offs: even when all 3 operands are int literals,
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// the return type doesn't get promoted to int:
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// final x = 1.clamp(0, 2); // The inferred return type is int, where as:
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// final f = 1.clamp;
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// final y = f(0, 2) // The inferred return type is num.
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PropertyAccess(
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target: Expression(staticType: DartType(isDartCoreDouble: true) || DartType(isDartCoreNum: true) || DartType(isDartCoreInt: true)),
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) => false,
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// Expressions like `final int x = 1.clamp(0, 2);` should be allowed.
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MethodInvocation(
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target: Expression(staticType: DartType(isDartCoreInt: true)),
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argumentList: ArgumentList(arguments: [Expression(staticType: DartType(isDartCoreInt: true)), Expression(staticType: DartType(isDartCoreInt: true))]),
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) => true,
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// Otherwise, disallow num.clamp() invocations.
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MethodInvocation(
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target: Expression(staticType: DartType(isDartCoreDouble: true) || DartType(isDartCoreNum: true) || DartType(isDartCoreInt: true)),
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) => false,
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_ => true,
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};
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if (!isAllowed) {
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clampAccessNodes.add(node);
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}
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}
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}
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