pkg/linter/lib/src/ast.dart - sdk - Git at Google

 // Copyright (c) 2015, 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.

 /// Common AST helpers.
 library;

 import 'package:analyzer/analysis_rule/rule_context.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/syntactic_entity.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/workspace/workspace.dart';
 import 'package:path/path.dart' as path;

 /// Return the compilation unit of a node
 CompilationUnit? getCompilationUnit(AstNode node) =>
     node.thisOrAncestorOfType<CompilationUnit>();

 /// Returns a field identifier with the given [name] in the given [decl]'s
 /// variable declaration list or `null` if none is found.
 Token? getFieldName(FieldDeclaration decl, String name) {
   for (var v in decl.fields.variables) {
     if (v.name.lexeme == name) {
       return v.name;
     }
   }
   return null;
 }

 /// Returns the value of an [IntegerLiteral] or [PrefixExpression] with a
 /// minus and then an [IntegerLiteral]. If a [context] is provided,
 /// [SimpleIdentifier]s are evaluated as constants. For anything else,
 /// returns `null`.
 int? getIntValue(Expression expression, RuleContext? context) {
   if (expression is PrefixExpression) {
     var operand = expression.operand;
     if (expression.operator.type != TokenType.MINUS) return null;
     return _getIntValue(operand, context, negated: true);
   }
   return _getIntValue(expression, context);
 }

 /// Returns the most specific AST node appropriate for associating errors.
 SyntacticEntity getNodeToAnnotate(Declaration node) {
   // TODO(srawlins): Convert to a switch expression over `Declaration` subtypes,
   // assuming `Declaration` becomes an exhaustive type.
   if (node is ClassDeclaration) {
     return node.name;
   }
   if (node is ClassTypeAlias) {
     return node.name;
   }
   if (node is ConstructorDeclaration) {
     return node.name ?? node.returnType;
   }
   if (node is EnumConstantDeclaration) {
     return node.name;
   }
   if (node is EnumDeclaration) {
     return node.name;
   }
   if (node is ExtensionDeclaration) {
     return node.name ?? node;
   }
   if (node is FieldDeclaration) {
     return node.fields;
   }
   if (node is FunctionDeclaration) {
     return node.name;
   }
   if (node is FunctionTypeAlias) {
     return node.name;
   }
   if (node is GenericTypeAlias) {
     return node.name;
   }
   if (node is MethodDeclaration) {
     return node.name;
   }
   if (node is MixinDeclaration) {
     return node.name;
   }
   if (node is TopLevelVariableDeclaration) {
     return node.variables;
   }
   if (node is TypeParameter) {
     return node.name;
   }
   if (node is VariableDeclaration) {
     return node.name;
   }
   if (node is ExtensionTypeDeclaration) {
     return node.name;
   }
   assert(false, "Unaccounted for Declaration subtype: '${node.runtimeType}'");
   return node;
 }

 /// If the [node] is the finishing identifier of an assignment, return its
 /// "writeElement", otherwise return its "element", which might be
 /// thought as the "readElement".
 Element? getWriteOrReadElement(SimpleIdentifier node) =>
     _getWriteElement(node) ?? node.element;

 bool hasConstantError(Expression node) =>
     node.computeConstantValue()?.diagnostics.isNotEmpty ?? true;

 /// Returns `true` if this element is the `==` method declaration.
 bool isEquals(ClassMember element) =>
     element is MethodDeclaration && element.name.lexeme == '==';

 /// Returns `true` if this element is a `hashCode` method or field declaration.
 bool isHashCode(ClassMember element) => _hasFieldOrMethod(element, 'hashCode');

 /// Returns `true` if this element is an `index` method or field declaration.
 bool isIndex(ClassMember element) => _hasFieldOrMethod(element, 'index');

 /// Return `true` if this compilation unit [node] is declared within a public
 /// directory in the given [package]'s directory tree. Public dirs are the
 /// `lib` and `bin` dirs and the build and link hook file.
 //
 // TODO(jakemac): move into WorkspacePackage
 bool isInPublicDir(CompilationUnit node, WorkspacePackage? package) {
   if (package == null) return false;
   var cuPath = node.declaredFragment?.element.firstFragment.source.fullName;
   if (cuPath == null) return false;
   var libDir = path.join(package.root.path, 'lib');
   var binDir = path.join(package.root.path, 'bin');
   // Hook directory: https://github.com/dart-lang/sdk/issues/54334,
   var buildHookFile = path.join(package.root.path, 'hook', 'build.dart');
   var linkHookFile = path.join(package.root.path, 'hook', 'link.dart');
   return path.isWithin(libDir, cuPath) ||
       path.isWithin(binDir, cuPath) ||
       cuPath == buildHookFile ||
       cuPath == linkHookFile;
 }

 /// Returns `true` if the given method [declaration] is a "simple getter".
 ///
 /// A simple getter takes one of these basic forms:
 ///
 /// ```dart
 /// get x => _simpleIdentifier;
 /// ```
 ///
 /// or
 ///
 /// ```dart
 /// get x {
 ///   return _simpleIdentifier;
 /// }
 /// ```
 bool isSimpleGetter(MethodDeclaration declaration) {
   if (!declaration.isGetter) {
     return false;
   }
   var body = declaration.body;
   if (body is ExpressionFunctionBody) {
     return _checkForSimpleGetter(declaration, body.expression);
   } else if (body is BlockFunctionBody) {
     var block = body.block;
     if (block.statements.length == 1) {
       var statement = block.statements.first;
       if (statement is ReturnStatement) {
         return _checkForSimpleGetter(declaration, statement.expression);
       }
     }
   }
   return false;
 }

 /// Returns `true` if the given [setter] is a "simple setter".
 ///
 /// A simple setter takes this basic form:
 ///
 /// ```dart
 /// int _x;
 /// set(int x) {
 ///   _x = x;
 /// }
 /// ```
 ///
 /// or:
 ///
 /// ```dart
 /// int _x;
 /// set(int x) => _x = x;
 /// ```
 ///
 /// where the static type of the left and right hand sides of the assignment
 /// expression are the same.
 bool isSimpleSetter(MethodDeclaration setter) {
   var body = setter.body;
   if (body is ExpressionFunctionBody) {
     return _checkForSimpleSetter(setter, body.expression);
   } else if (body is BlockFunctionBody) {
     var block = body.block;
     if (block.statements.length == 1) {
       var statement = block.statements.first;
       if (statement is ExpressionStatement) {
         return _checkForSimpleSetter(setter, statement.expression);
       }
     }
   }

   return false;
 }

 /// Returns `true` if this element is a `values` method or field declaration.
 bool isValues(ClassMember element) => _hasFieldOrMethod(element, 'values');

 /// Return the nearest enclosing pubspec file.
 File? locatePubspecFile(CompilationUnit compilationUnit) {
   var declaredFragment = compilationUnit.declaredFragment;
   if (declaredFragment == null) return null;

   var fullName = declaredFragment.source.fullName;
   var resourceProvider = declaredFragment.element.session.resourceProvider;

   var file = resourceProvider.getFile(fullName);

   // Look for a pubspec.yaml file.
   for (var folder in file.parent.withAncestors) {
     var pubspecFile = folder.getChildAssumingFile('pubspec.yaml');
     if (pubspecFile.exists) {
       return pubspecFile;
     }
   }

   return null;
 }

 bool _checkForSimpleGetter(MethodDeclaration getter, Expression? expression) {
   if (expression is SimpleIdentifier) {
     var staticElement = expression.element;
     if (staticElement is GetterElement) {
       var enclosingElement = getter.declaredFragment?.element.enclosingElement;
       // Skipping library level getters, test that the enclosing element is
       // the same
       if (staticElement.enclosingElement == enclosingElement) {
         var variable = staticElement.variable;
         return staticElement.isSynthetic && variable.isPrivate;
       }
     }
   }
   return false;
 }

 bool _checkForSimpleSetter(MethodDeclaration setter, Expression expression) {
   if (expression is! AssignmentExpression) {
     return false;
   }
   if (expression.operator.type != TokenType.EQ) {
     return false;
   }

   var leftHandSide = expression.leftHandSide;
   var rightHandSide = expression.rightHandSide;
   if (leftHandSide is SimpleIdentifier && rightHandSide is SimpleIdentifier) {
     var leftElement = expression.writeElement;
     if (leftElement is! SetterElement || !leftElement.isSynthetic) {
       return false;
     }

     // To guard against setters used as type constraints
     if (expression.writeType != rightHandSide.staticType) {
       return false;
     }

     var rightElement = rightHandSide.element;
     if (rightElement is! FormalParameterElement) {
       return false;
     }

     var parameters = setter.parameters?.parameters;
     if (parameters != null && parameters.length == 1) {
       return rightElement == parameters.first.declaredFragment?.element;
     }
   }

   return false;
 }

 int? _getIntValue(
   Expression expression,
   RuleContext? context, {
   bool negated = false,
 }) {
   int? value;
   if (expression is IntegerLiteral) {
     value = expression.value;
   } else if (expression is SimpleIdentifier && context != null) {
     value = expression.computeConstantValue()?.value?.toIntValue();
   }
   if (value is! int) return null;

   return negated ? -value : value;
 }

 /// If the [node] is the target of a [CompoundAssignmentExpression],
 /// return the corresponding "writeElement", which is the local variable,
 /// the setter referenced with a [SimpleIdentifier] or a [PropertyAccess],
 /// or the `[]=` operator.
 Element? _getWriteElement(AstNode node) {
   var parent = node.parent;
   if (parent is AssignmentExpression && parent.leftHandSide == node) {
     return parent.writeElement;
   }
   if (parent is PostfixExpression) {
     return parent.writeElement;
   }
   if (parent is PrefixExpression) {
     return parent.writeElement;
   }

   if (parent is PrefixedIdentifier && parent.identifier == node) {
     return _getWriteElement(parent);
   }

   if (parent is PropertyAccess && parent.propertyName == node) {
     return _getWriteElement(parent);
   }

   return null;
 }

 bool _hasFieldOrMethod(ClassMember element, String name) =>
     (element is MethodDeclaration && element.name.lexeme == name) ||
     (element is FieldDeclaration && getFieldName(element, name) != null);

 extension AstNodeExtension on AstNode {
   bool get isToStringInvocationWithArguments {
     var self = this;
     return self is MethodInvocation &&
         self.methodName.name == 'toString' &&
         self.argumentList.arguments.isNotEmpty;
   }
 }
	// Copyright (c) 2015, 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.

	/// Common AST helpers.
	library;

	import 'package:analyzer/analysis_rule/rule_context.dart';
	import 'package:analyzer/dart/ast/ast.dart';
	import 'package:analyzer/dart/ast/syntactic_entity.dart';
	import 'package:analyzer/dart/ast/token.dart';
	import 'package:analyzer/dart/element/element.dart';
	import 'package:analyzer/file_system/file_system.dart';
	import 'package:analyzer/workspace/workspace.dart';
	import 'package:path/path.dart' as path;

	/// Return the compilation unit of a node
	CompilationUnit? getCompilationUnit(AstNode node) =>
	node.thisOrAncestorOfType<CompilationUnit>();

	/// Returns a field identifier with the given [name] in the given [decl]'s
	/// variable declaration list or `null` if none is found.
	Token? getFieldName(FieldDeclaration decl, String name) {
	for (var v in decl.fields.variables) {
	if (v.name.lexeme == name) {
	return v.name;
	}
	}
	return null;
	}

	/// Returns the value of an [IntegerLiteral] or [PrefixExpression] with a
	/// minus and then an [IntegerLiteral]. If a [context] is provided,
	/// [SimpleIdentifier]s are evaluated as constants. For anything else,
	/// returns `null`.
	int? getIntValue(Expression expression, RuleContext? context) {
	if (expression is PrefixExpression) {
	var operand = expression.operand;
	if (expression.operator.type != TokenType.MINUS) return null;
	return _getIntValue(operand, context, negated: true);
	}
	return _getIntValue(expression, context);
	}

	/// Returns the most specific AST node appropriate for associating errors.
	SyntacticEntity getNodeToAnnotate(Declaration node) {
	// TODO(srawlins): Convert to a switch expression over `Declaration` subtypes,
	// assuming `Declaration` becomes an exhaustive type.
	if (node is ClassDeclaration) {
	return node.name;
	}
	if (node is ClassTypeAlias) {
	return node.name;
	}
	if (node is ConstructorDeclaration) {
	return node.name ?? node.returnType;
	}
	if (node is EnumConstantDeclaration) {
	return node.name;
	}
	if (node is EnumDeclaration) {
	return node.name;
	}
	if (node is ExtensionDeclaration) {
	return node.name ?? node;
	}
	if (node is FieldDeclaration) {
	return node.fields;
	}
	if (node is FunctionDeclaration) {
	return node.name;
	}
	if (node is FunctionTypeAlias) {
	return node.name;
	}
	if (node is GenericTypeAlias) {
	return node.name;
	}
	if (node is MethodDeclaration) {
	return node.name;
	}
	if (node is MixinDeclaration) {
	return node.name;
	}
	if (node is TopLevelVariableDeclaration) {
	return node.variables;
	}
	if (node is TypeParameter) {
	return node.name;
	}
	if (node is VariableDeclaration) {
	return node.name;
	}
	if (node is ExtensionTypeDeclaration) {
	return node.name;
	}
	assert(false, "Unaccounted for Declaration subtype: '${node.runtimeType}'");
	return node;
	}

	/// If the [node] is the finishing identifier of an assignment, return its
	/// "writeElement", otherwise return its "element", which might be
	/// thought as the "readElement".
	Element? getWriteOrReadElement(SimpleIdentifier node) =>
	_getWriteElement(node) ?? node.element;

	bool hasConstantError(Expression node) =>
	node.computeConstantValue()?.diagnostics.isNotEmpty ?? true;

	/// Returns `true` if this element is the `==` method declaration.
	bool isEquals(ClassMember element) =>
	element is MethodDeclaration && element.name.lexeme == '==';

	/// Returns `true` if this element is a `hashCode` method or field declaration.
	bool isHashCode(ClassMember element) => _hasFieldOrMethod(element, 'hashCode');

	/// Returns `true` if this element is an `index` method or field declaration.
	bool isIndex(ClassMember element) => _hasFieldOrMethod(element, 'index');

	/// Return `true` if this compilation unit [node] is declared within a public
	/// directory in the given [package]'s directory tree. Public dirs are the
	/// `lib` and `bin` dirs and the build and link hook file.
	//
	// TODO(jakemac): move into WorkspacePackage
	bool isInPublicDir(CompilationUnit node, WorkspacePackage? package) {
	if (package == null) return false;
	var cuPath = node.declaredFragment?.element.firstFragment.source.fullName;
	if (cuPath == null) return false;
	var libDir = path.join(package.root.path, 'lib');
	var binDir = path.join(package.root.path, 'bin');
	// Hook directory: https://github.com/dart-lang/sdk/issues/54334,
	var buildHookFile = path.join(package.root.path, 'hook', 'build.dart');
	var linkHookFile = path.join(package.root.path, 'hook', 'link.dart');
	return path.isWithin(libDir, cuPath) \|\|
	path.isWithin(binDir, cuPath) \|\|
	cuPath == buildHookFile \|\|
	cuPath == linkHookFile;
	}

	/// Returns `true` if the given method [declaration] is a "simple getter".
	///
	/// A simple getter takes one of these basic forms:
	///
	/// ```dart
	/// get x => _simpleIdentifier;
	/// ```
	///
	/// or
	///
	/// ```dart
	/// get x {
	/// return _simpleIdentifier;
	/// }
	/// ```
	bool isSimpleGetter(MethodDeclaration declaration) {
	if (!declaration.isGetter) {
	return false;
	}
	var body = declaration.body;
	if (body is ExpressionFunctionBody) {
	return _checkForSimpleGetter(declaration, body.expression);
	} else if (body is BlockFunctionBody) {
	var block = body.block;
	if (block.statements.length == 1) {
	var statement = block.statements.first;
	if (statement is ReturnStatement) {
	return _checkForSimpleGetter(declaration, statement.expression);
	}
	}
	}
	return false;
	}

	/// Returns `true` if the given [setter] is a "simple setter".
	///
	/// A simple setter takes this basic form:
	///
	/// ```dart
	/// int _x;
	/// set(int x) {
	/// _x = x;
	/// }
	/// ```
	///
	/// or:
	///
	/// ```dart
	/// int _x;
	/// set(int x) => _x = x;
	/// ```
	///
	/// where the static type of the left and right hand sides of the assignment
	/// expression are the same.
	bool isSimpleSetter(MethodDeclaration setter) {
	var body = setter.body;
	if (body is ExpressionFunctionBody) {
	return _checkForSimpleSetter(setter, body.expression);
	} else if (body is BlockFunctionBody) {
	var block = body.block;
	if (block.statements.length == 1) {
	var statement = block.statements.first;
	if (statement is ExpressionStatement) {
	return _checkForSimpleSetter(setter, statement.expression);
	}
	}
	}

	return false;
	}

	/// Returns `true` if this element is a `values` method or field declaration.
	bool isValues(ClassMember element) => _hasFieldOrMethod(element, 'values');

	/// Return the nearest enclosing pubspec file.
	File? locatePubspecFile(CompilationUnit compilationUnit) {
	var declaredFragment = compilationUnit.declaredFragment;
	if (declaredFragment == null) return null;

	var fullName = declaredFragment.source.fullName;
	var resourceProvider = declaredFragment.element.session.resourceProvider;

	var file = resourceProvider.getFile(fullName);

	// Look for a pubspec.yaml file.
	for (var folder in file.parent.withAncestors) {
	var pubspecFile = folder.getChildAssumingFile('pubspec.yaml');
	if (pubspecFile.exists) {
	return pubspecFile;
	}
	}

	return null;
	}

	bool _checkForSimpleGetter(MethodDeclaration getter, Expression? expression) {
	if (expression is SimpleIdentifier) {
	var staticElement = expression.element;
	if (staticElement is GetterElement) {
	var enclosingElement = getter.declaredFragment?.element.enclosingElement;
	// Skipping library level getters, test that the enclosing element is
	// the same
	if (staticElement.enclosingElement == enclosingElement) {
	var variable = staticElement.variable;
	return staticElement.isSynthetic && variable.isPrivate;
	}
	}
	}
	return false;
	}

	bool _checkForSimpleSetter(MethodDeclaration setter, Expression expression) {
	if (expression is! AssignmentExpression) {
	return false;
	}
	if (expression.operator.type != TokenType.EQ) {
	return false;
	}

	var leftHandSide = expression.leftHandSide;
	var rightHandSide = expression.rightHandSide;
	if (leftHandSide is SimpleIdentifier && rightHandSide is SimpleIdentifier) {
	var leftElement = expression.writeElement;
	if (leftElement is! SetterElement \|\| !leftElement.isSynthetic) {
	return false;
	}

	// To guard against setters used as type constraints
	if (expression.writeType != rightHandSide.staticType) {
	return false;
	}

	var rightElement = rightHandSide.element;
	if (rightElement is! FormalParameterElement) {
	return false;
	}

	var parameters = setter.parameters?.parameters;
	if (parameters != null && parameters.length == 1) {
	return rightElement == parameters.first.declaredFragment?.element;
	}
	}

	return false;
	}

	int? _getIntValue(
	Expression expression,
	RuleContext? context, {
	bool negated = false,
	}) {
	int? value;
	if (expression is IntegerLiteral) {
	value = expression.value;
	} else if (expression is SimpleIdentifier && context != null) {
	value = expression.computeConstantValue()?.value?.toIntValue();
	}
	if (value is! int) return null;

	return negated ? -value : value;
	}

	/// If the [node] is the target of a [CompoundAssignmentExpression],
	/// return the corresponding "writeElement", which is the local variable,
	/// the setter referenced with a [SimpleIdentifier] or a [PropertyAccess],
	/// or the `[]=` operator.
	Element? _getWriteElement(AstNode node) {
	var parent = node.parent;
	if (parent is AssignmentExpression && parent.leftHandSide == node) {
	return parent.writeElement;
	}
	if (parent is PostfixExpression) {
	return parent.writeElement;
	}
	if (parent is PrefixExpression) {
	return parent.writeElement;
	}

	if (parent is PrefixedIdentifier && parent.identifier == node) {
	return _getWriteElement(parent);
	}

	if (parent is PropertyAccess && parent.propertyName == node) {
	return _getWriteElement(parent);
	}

	return null;
	}

	bool _hasFieldOrMethod(ClassMember element, String name) =>
	(element is MethodDeclaration && element.name.lexeme == name) \|\|
	(element is FieldDeclaration && getFieldName(element, name) != null);

	extension AstNodeExtension on AstNode {
	bool get isToStringInvocationWithArguments {
	var self = this;
	return self is MethodInvocation &&
	self.methodName.name == 'toString' &&
	self.argumentList.arguments.isNotEmpty;
	}
	}