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

 // 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.

 /// @docImport 'package:analyzer/src/lint/linter_visitor.dart';
 library;

 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/dart/ast/ast.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisEngine;

 export 'package:analyzer/src/dart/ast/constant_evaluator.dart';

 /// An object used to locate the [AstNode] associated with a source range.
 /// More specifically, they will return the deepest [AstNode] which completely
 /// encompasses the specified range with some exceptions:
 ///
 /// - Offsets that fall between the name and type/formal parameter list of a
 ///   declaration will return the declaration node and not the parameter list
 ///   node.
 class NodeLocator2 extends UnifyingAstVisitor<void> {
   /// The inclusive start offset of the range used to identify the node.
   final int _startOffset;

   /// The inclusive end offset of the range used to identify the node.
   final int _endOffset;

   /// The found node or `null` if there is no such node.
   AstNode? _foundNode;

   /// Initialize a newly created locator to locate the deepest [AstNode] for
   /// which `node.offset <= [startOffset]` and `[endOffset] < node.end`.
   ///
   /// If [endOffset] is not provided, then it is considered the same as the
   /// given [startOffset].
   NodeLocator2(int startOffset, [int? endOffset])
     : _startOffset = startOffset,
       _endOffset = endOffset ?? startOffset;

   /// Search within the given AST [node] and return the node that was found,
   /// or `null` if no node was found.
   AstNode? searchWithin(AstNode? node) {
     if (node == null) {
       return null;
     }
     try {
       node.accept(this);
     } catch (exception, stackTrace) {
       // TODO(39284): should this exception be silent?
       AnalysisEngine.instance.instrumentationService.logException(
         SilentException(
           'Unable to locate element at offset '
           '($_startOffset - $_endOffset)',
           exception,
           stackTrace,
         ),
       );
       return null;
     }
     return _foundNode;
   }

   @override
   void visitClassDeclaration(ClassDeclaration node) {
     // Names do not have AstNodes but offsets at the end should be treated as
     // part of the declaration (not parameter list).
     if (_startOffset == _endOffset &&
         _startOffset == node.namePart.typeName.end) {
       _foundNode = node;
       return;
     }

     super.visitClassDeclaration(node);
   }

   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
     // Names do not have AstNodes but offsets at the end should be treated as
     // part of the declaration (not parameter list).
     if (_startOffset == _endOffset) {
       var end = node.name?.end ?? node.typeName?.end;
       if (end != null && _startOffset == end) {
         _foundNode = node;
         return;
       }
     }

     super.visitConstructorDeclaration(node);
   }

   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
     // Names do not have AstNodes but offsets at the end should be treated as
     // part of the declaration (not parameter list).
     if (_startOffset == _endOffset && _startOffset == node.name.end) {
       _foundNode = node;
       return;
     }

     super.visitFunctionDeclaration(node);
   }

   @override
   void visitMethodDeclaration(MethodDeclaration node) {
     // Names do not have AstNodes but offsets at the end should be treated as
     // part of the declaration (not parameter list).
     if (_startOffset == _endOffset && _startOffset == node.name.end) {
       _foundNode = node;
       return;
     }

     super.visitMethodDeclaration(node);
   }

   @override
   void visitNode(AstNode node) {
     // Don't visit a new tree if the result has been already found.
     if (_foundNode != null) {
       return;
     }
     // Check whether the current node covers the selection.
     Token beginToken = node.beginToken;
     Token endToken = node.endToken;
     // Don't include synthetic tokens.
     while (endToken != beginToken) {
       // Fasta scanner reports unterminated string literal errors
       // and generates a synthetic string token with non-zero length.
       // Because of this, check for length > 0 rather than !isSynthetic.
       if (endToken.isEof || endToken.length > 0) {
         break;
       }
       endToken = endToken.previous!;
     }
     int end = endToken.end;
     int start = node.offset;
     if (end <= _startOffset || start > _endOffset) {
       return;
     }
     // Check children.
     try {
       node.visitChildren(this);
     } catch (exception, stackTrace) {
       // Ignore the exception and proceed in order to visit the rest of the
       // structure.
       // TODO(39284): should this exception be silent?
       AnalysisEngine.instance.instrumentationService.logException(
         SilentException(
           "Exception caught while traversing an AST structure.",
           exception,
           stackTrace,
         ),
       );
     }
     // Found a child.
     if (_foundNode != null) {
       return;
     }
     // Check this node.
     if (start <= _startOffset && _endOffset < end) {
       _foundNode = node;
     }
   }
 }

 /// Traverse the AST from initial child node to successive parents, building a
 /// collection of local variable and parameter names visible to the initial
 /// child node. In case of name shadowing, the first name seen is the most
 /// specific one so names are not redefined.
 ///
 /// Completion test code coverage is 95%. The two basic blocks that are not
 /// executed cannot be executed. They are included for future reference.
 class ScopedNameFinder extends GeneralizingAstVisitor<void> {
   Declaration? _declarationNode;

   AstNode? _immediateChild;

   final Set<String> _locals = {};

   final int _position;

   bool _referenceIsWithinLocalFunction = false;

   ScopedNameFinder(this._position);

   Declaration? get declaration => _declarationNode;

   Set<String> get locals => _locals;

   @override
   void visitBlock(Block node) {
     _checkStatements(node.statements);
     super.visitBlock(node);
   }

   @override
   void visitCatchClause(CatchClause node) {
     _addToScope(node.exceptionParameter?.name);
     _addToScope(node.stackTraceParameter?.name);
     super.visitCatchClause(node);
   }

   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
     if (!identical(_immediateChild, node.parameters)) {
       _addParameters(node.parameters.parameters);
     }
     _declarationNode = node;
   }

   @override
   void visitFieldDeclaration(FieldDeclaration node) {
     _declarationNode = node;
   }

   @override
   void visitForEachPartsWithDeclaration(ForEachPartsWithDeclaration node) {
     _addToScope(node.loopVariable.name);
     super.visitForEachPartsWithDeclaration(node);
   }

   @override
   void visitForPartsWithDeclarations(ForPartsWithDeclarations node) {
     _addVariables(node.variables.variables);
     super.visitForPartsWithDeclarations(node);
   }

   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
     if (node.parent is! FunctionDeclarationStatement) {
       _declarationNode = node;
     } else {
       super.visitFunctionDeclaration(node);
     }
   }

   @override
   void visitFunctionDeclarationStatement(FunctionDeclarationStatement node) {
     _referenceIsWithinLocalFunction = true;
     super.visitFunctionDeclarationStatement(node);
   }

   @override
   void visitFunctionExpression(FunctionExpression node) {
     var parameters = node.parameters;
     if (parameters != null && !identical(_immediateChild, parameters)) {
       _addParameters(parameters.parameters);
     }
     super.visitFunctionExpression(node);
   }

   @override
   void visitMethodDeclaration(MethodDeclaration node) {
     _declarationNode = node;
     var parameters = node.parameters;
     if (parameters != null && !identical(_immediateChild, parameters)) {
       _addParameters(parameters.parameters);
     }
   }

   @override
   void visitNode(AstNode node) {
     _immediateChild = node;
     node.parent?.accept(this);
   }

   @override
   void visitSwitchMember(SwitchMember node) {
     _checkStatements(node.statements);
     super.visitSwitchMember(node);
   }

   @override
   void visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) {
     _declarationNode = node;
   }

   @override
   void visitTypeAlias(TypeAlias node) {
     _declarationNode = node;
   }

   void _addParameters(NodeList<FormalParameter> vars) {
     for (FormalParameter var2 in vars) {
       _addToScope(var2.name);
     }
   }

   void _addToScope(Token? identifier) {
     if (identifier != null && _isInRange(identifier)) {
       _locals.add(identifier.lexeme);
     }
   }

   void _addVariables(NodeList<VariableDeclaration> variables) {
     for (VariableDeclaration variable in variables) {
       _addToScope(variable.name);
     }
   }

   /// Check the given list of [statements] for any that come before the
   /// immediate child and that define a name that would be visible to the
   /// immediate child.
   void _checkStatements(List<Statement> statements) {
     for (Statement statement in statements) {
       if (identical(statement, _immediateChild)) {
         return;
       }
       if (statement is VariableDeclarationStatement) {
         _addVariables(statement.variables.variables);
       } else if (statement is FunctionDeclarationStatement &&
           !_referenceIsWithinLocalFunction) {
         _addToScope(statement.functionDeclaration.name);
       }
     }
   }

   bool _isInRange(Token token) {
     if (_position < 0) {
       // if source position is not set then all nodes are in range
       return true;
       // not reached
     }
     return token.end < _position;
   }
 }
	// 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.

	/// @docImport 'package:analyzer/src/lint/linter_visitor.dart';
	library;

	import 'package:analyzer/dart/ast/token.dart';
	import 'package:analyzer/dart/ast/visitor.dart';
	import 'package:analyzer/exception/exception.dart';
	import 'package:analyzer/src/dart/ast/ast.dart';
	import 'package:analyzer/src/generated/engine.dart' show AnalysisEngine;

	export 'package:analyzer/src/dart/ast/constant_evaluator.dart';

	/// An object used to locate the [AstNode] associated with a source range.
	/// More specifically, they will return the deepest [AstNode] which completely
	/// encompasses the specified range with some exceptions:
	///
	/// - Offsets that fall between the name and type/formal parameter list of a
	/// declaration will return the declaration node and not the parameter list
	/// node.
	class NodeLocator2 extends UnifyingAstVisitor<void> {
	/// The inclusive start offset of the range used to identify the node.
	final int _startOffset;

	/// The inclusive end offset of the range used to identify the node.
	final int _endOffset;

	/// The found node or `null` if there is no such node.
	AstNode? _foundNode;

	/// Initialize a newly created locator to locate the deepest [AstNode] for
	/// which `node.offset <= [startOffset]` and `[endOffset] < node.end`.
	///
	/// If [endOffset] is not provided, then it is considered the same as the
	/// given [startOffset].
	NodeLocator2(int startOffset, [int? endOffset])
	: _startOffset = startOffset,
	_endOffset = endOffset ?? startOffset;

	/// Search within the given AST [node] and return the node that was found,
	/// or `null` if no node was found.
	AstNode? searchWithin(AstNode? node) {
	if (node == null) {
	return null;
	}
	try {
	node.accept(this);
	} catch (exception, stackTrace) {
	// TODO(39284): should this exception be silent?
	AnalysisEngine.instance.instrumentationService.logException(
	SilentException(
	'Unable to locate element at offset '
	'($_startOffset - $_endOffset)',
	exception,
	stackTrace,
	),
	);
	return null;
	}
	return _foundNode;
	}

	@override
	void visitClassDeclaration(ClassDeclaration node) {
	// Names do not have AstNodes but offsets at the end should be treated as
	// part of the declaration (not parameter list).
	if (_startOffset == _endOffset &&
	_startOffset == node.namePart.typeName.end) {
	_foundNode = node;
	return;
	}

	super.visitClassDeclaration(node);
	}

	@override
	void visitConstructorDeclaration(ConstructorDeclaration node) {
	// Names do not have AstNodes but offsets at the end should be treated as
	// part of the declaration (not parameter list).
	if (_startOffset == _endOffset) {
	var end = node.name?.end ?? node.typeName?.end;
	if (end != null && _startOffset == end) {
	_foundNode = node;
	return;
	}
	}

	super.visitConstructorDeclaration(node);
	}

	@override
	void visitFunctionDeclaration(FunctionDeclaration node) {
	// Names do not have AstNodes but offsets at the end should be treated as
	// part of the declaration (not parameter list).
	if (_startOffset == _endOffset && _startOffset == node.name.end) {
	_foundNode = node;
	return;
	}

	super.visitFunctionDeclaration(node);
	}

	@override
	void visitMethodDeclaration(MethodDeclaration node) {
	// Names do not have AstNodes but offsets at the end should be treated as
	// part of the declaration (not parameter list).
	if (_startOffset == _endOffset && _startOffset == node.name.end) {
	_foundNode = node;
	return;
	}

	super.visitMethodDeclaration(node);
	}

	@override
	void visitNode(AstNode node) {
	// Don't visit a new tree if the result has been already found.
	if (_foundNode != null) {
	return;
	}
	// Check whether the current node covers the selection.
	Token beginToken = node.beginToken;
	Token endToken = node.endToken;
	// Don't include synthetic tokens.
	while (endToken != beginToken) {
	// Fasta scanner reports unterminated string literal errors
	// and generates a synthetic string token with non-zero length.
	// Because of this, check for length > 0 rather than !isSynthetic.
	if (endToken.isEof \|\| endToken.length > 0) {
	break;
	}
	endToken = endToken.previous!;
	}
	int end = endToken.end;
	int start = node.offset;
	if (end <= _startOffset \|\| start > _endOffset) {
	return;
	}
	// Check children.
	try {
	node.visitChildren(this);
	} catch (exception, stackTrace) {
	// Ignore the exception and proceed in order to visit the rest of the
	// structure.
	// TODO(39284): should this exception be silent?
	AnalysisEngine.instance.instrumentationService.logException(
	SilentException(
	"Exception caught while traversing an AST structure.",
	exception,
	stackTrace,
	),
	);
	}
	// Found a child.
	if (_foundNode != null) {
	return;
	}
	// Check this node.
	if (start <= _startOffset && _endOffset < end) {
	_foundNode = node;
	}
	}
	}

	/// Traverse the AST from initial child node to successive parents, building a
	/// collection of local variable and parameter names visible to the initial
	/// child node. In case of name shadowing, the first name seen is the most
	/// specific one so names are not redefined.
	///
	/// Completion test code coverage is 95%. The two basic blocks that are not
	/// executed cannot be executed. They are included for future reference.
	class ScopedNameFinder extends GeneralizingAstVisitor<void> {
	Declaration? _declarationNode;

	AstNode? _immediateChild;

	final Set<String> _locals = {};

	final int _position;

	bool _referenceIsWithinLocalFunction = false;

	ScopedNameFinder(this._position);

	Declaration? get declaration => _declarationNode;

	Set<String> get locals => _locals;

	@override
	void visitBlock(Block node) {
	_checkStatements(node.statements);
	super.visitBlock(node);
	}

	@override
	void visitCatchClause(CatchClause node) {
	_addToScope(node.exceptionParameter?.name);
	_addToScope(node.stackTraceParameter?.name);
	super.visitCatchClause(node);
	}

	@override
	void visitConstructorDeclaration(ConstructorDeclaration node) {
	if (!identical(_immediateChild, node.parameters)) {
	_addParameters(node.parameters.parameters);
	}
	_declarationNode = node;
	}

	@override
	void visitFieldDeclaration(FieldDeclaration node) {
	_declarationNode = node;
	}

	@override
	void visitForEachPartsWithDeclaration(ForEachPartsWithDeclaration node) {
	_addToScope(node.loopVariable.name);
	super.visitForEachPartsWithDeclaration(node);
	}

	@override
	void visitForPartsWithDeclarations(ForPartsWithDeclarations node) {
	_addVariables(node.variables.variables);
	super.visitForPartsWithDeclarations(node);
	}

	@override
	void visitFunctionDeclaration(FunctionDeclaration node) {
	if (node.parent is! FunctionDeclarationStatement) {
	_declarationNode = node;
	} else {
	super.visitFunctionDeclaration(node);
	}
	}

	@override
	void visitFunctionDeclarationStatement(FunctionDeclarationStatement node) {
	_referenceIsWithinLocalFunction = true;
	super.visitFunctionDeclarationStatement(node);
	}

	@override
	void visitFunctionExpression(FunctionExpression node) {
	var parameters = node.parameters;
	if (parameters != null && !identical(_immediateChild, parameters)) {
	_addParameters(parameters.parameters);
	}
	super.visitFunctionExpression(node);
	}

	@override
	void visitMethodDeclaration(MethodDeclaration node) {
	_declarationNode = node;
	var parameters = node.parameters;
	if (parameters != null && !identical(_immediateChild, parameters)) {
	_addParameters(parameters.parameters);
	}
	}

	@override
	void visitNode(AstNode node) {
	_immediateChild = node;
	node.parent?.accept(this);
	}

	@override
	void visitSwitchMember(SwitchMember node) {
	_checkStatements(node.statements);
	super.visitSwitchMember(node);
	}

	@override
	void visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) {
	_declarationNode = node;
	}

	@override
	void visitTypeAlias(TypeAlias node) {
	_declarationNode = node;
	}

	void _addParameters(NodeList<FormalParameter> vars) {
	for (FormalParameter var2 in vars) {
	_addToScope(var2.name);
	}
	}

	void _addToScope(Token? identifier) {
	if (identifier != null && _isInRange(identifier)) {
	_locals.add(identifier.lexeme);
	}
	}

	void _addVariables(NodeList<VariableDeclaration> variables) {
	for (VariableDeclaration variable in variables) {
	_addToScope(variable.name);
	}
	}

	/// Check the given list of [statements] for any that come before the
	/// immediate child and that define a name that would be visible to the
	/// immediate child.
	void _checkStatements(List<Statement> statements) {
	for (Statement statement in statements) {
	if (identical(statement, _immediateChild)) {
	return;
	}
	if (statement is VariableDeclarationStatement) {
	_addVariables(statement.variables.variables);
	} else if (statement is FunctionDeclarationStatement &&
	!_referenceIsWithinLocalFunction) {
	_addToScope(statement.functionDeclaration.name);
	}
	}
	}

	bool _isInRange(Token token) {
	if (_position < 0) {
	// if source position is not set then all nodes are in range
	return true;
	// not reached
	}
	return token.end < _position;
	}
	}