pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_stateful_widget.dart - sdk.git - Git at Google

 // 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/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/source/source_range.dart';
 import 'package:analyzer/src/dart/ast/extensions.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart' hide Element;
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/range_factory.dart';

 class FlutterConvertToStatefulWidget extends CorrectionProducer {
   @override
   AssistKind get assistKind =>
       DartAssistKind.FLUTTER_CONVERT_TO_STATEFUL_WIDGET;

   @override
   Future<void> compute(ChangeBuilder builder) async {
     var widgetClass = node.thisOrAncestorOfType<ClassDeclaration>();
     var superclass = widgetClass?.extendsClause?.superclass2;
     if (widgetClass == null || superclass == null) {
       return;
     }

     // Don't spam, activate only from the `class` keyword to the class body.
     if (selectionOffset < widgetClass.classKeyword.offset ||
         selectionOffset > widgetClass.leftBracket.end) {
       return;
     }

     // Find the build() method.
     MethodDeclaration? buildMethod;
     for (var member in widgetClass.members) {
       if (member is MethodDeclaration && member.name.name == 'build') {
         var parameters = member.parameters;
         if (parameters != null && parameters.parameters.length == 1) {
           buildMethod = member;
           break;
         }
       }
     }
     if (buildMethod == null) {
       return;
     }

     // Must be a StatelessWidget subclasses.
     var widgetClassElement = widgetClass.declaredElement!;
     var superType = widgetClassElement.supertype;
     if (superType == null || !flutter.isExactlyStatelessWidgetType(superType)) {
       return;
     }

     var widgetName = widgetClassElement.displayName;
     var stateName = widgetClassElement.isPrivate
         ? '${widgetName}State'
         : '_${widgetName}State';

     // Find fields assigned in constructors.
     var visitor = _FieldFinder();
     for (var member in widgetClass.members) {
       if (member is ConstructorDeclaration) {
         member.accept(visitor);
       }
     }
     var fieldsAssignedInConstructors = visitor.fieldsAssignedInConstructors;

     // Prepare nodes to move.
     var nodesToMove = <ClassMember>{};
     var elementsToMove = <Element>{};
     for (var member in widgetClass.members) {
       if (member is FieldDeclaration && !member.isStatic) {
         for (var fieldNode in member.fields.variables) {
           var fieldElement = fieldNode.declaredElement as FieldElement;
           if (!fieldsAssignedInConstructors.contains(fieldElement)) {
             nodesToMove.add(member);
             elementsToMove.add(fieldElement);

             var getter = fieldElement.getter;
             if (getter != null) {
               elementsToMove.add(getter);
             }

             var setter = fieldElement.setter;
             if (setter != null) {
               elementsToMove.add(setter);
             }
           }
         }
       } else if (member is MethodDeclaration && !member.isStatic) {
         nodesToMove.add(member);
         elementsToMove.add(member.declaredElement!);
       }
     }

     /// Return the code for the [movedNode] which is suitable to be used
     /// inside the `State` class, so that references to the widget fields and
     /// methods, that are not moved, are qualified with the corresponding
     /// instance `widget.`, or static `MyWidgetClass.` qualifier.
     String rewriteWidgetMemberReferences(AstNode movedNode) {
       var linesRange = utils.getLinesRange(range.node(movedNode));
       var text = utils.getRangeText(linesRange);

       // Insert `widget.` before references to the widget instance members.
       var visitor = _ReplacementEditBuilder(
           widgetClassElement, elementsToMove, linesRange);
       movedNode.accept(visitor);
       return SourceEdit.applySequence(text, visitor.edits.reversed);
     }

     var statefulWidgetClass = await sessionHelper.getClass(
       flutter.widgetsUri,
       'StatefulWidget',
     );
     var stateClass = await sessionHelper.getClass(
       flutter.widgetsUri,
       'State',
     );
     if (statefulWidgetClass == null || stateClass == null) {
       return;
     }

     await builder.addDartFileEdit(file, (builder) {
       builder.addReplacement(range.node(superclass), (builder) {
         builder.writeReference(statefulWidgetClass);
       });

       var replaceOffset = 0;
       var hasBuildMethod = false;

       var typeParams = '';
       var typeParameters = widgetClass.typeParameters;
       if (typeParameters != null) {
         typeParams = utils.getNodeText(typeParameters);
       }

       /// Replace code between [replaceOffset] and [replaceEnd] with
       /// `createState()`, empty line, or nothing.
       void replaceInterval(int replaceEnd,
           {bool replaceWithEmptyLine = false,
           bool hasEmptyLineBeforeCreateState = false,
           bool hasEmptyLineAfterCreateState = true}) {
         var replaceLength = replaceEnd - replaceOffset;
         builder.addReplacement(
           SourceRange(replaceOffset, replaceLength),
           (builder) {
             if (hasBuildMethod) {
               if (hasEmptyLineBeforeCreateState) {
                 builder.writeln();
               }
               builder.writeln('  @override');
               builder.write('  ');
               builder.writeReference(stateClass);
               builder.write('<${widgetClass.name}$typeParams>');
               builder.writeln(' createState() => $stateName$typeParams();');
               if (hasEmptyLineAfterCreateState) {
                 builder.writeln();
               }
               hasBuildMethod = false;
             } else if (replaceWithEmptyLine) {
               builder.writeln();
             }
           },
         );
         replaceOffset = 0;
       }

       // Remove continuous ranges of lines of nodes being moved.
       var lastToRemoveIsField = false;
       var endOfLastNodeToKeep = 0;
       for (var node in widgetClass.members) {
         if (nodesToMove.contains(node)) {
           if (replaceOffset == 0) {
             var comments = node.beginToken.precedingComments;
             var start = comments ?? node;
             replaceOffset = utils.getLineContentStart(start.offset);
           }
           if (node == buildMethod) {
             hasBuildMethod = true;
           }
           lastToRemoveIsField = node is FieldDeclaration;
         } else {
           var linesRange = utils.getLinesRange(range.node(node));
           endOfLastNodeToKeep = linesRange.end;
           if (replaceOffset != 0) {
             replaceInterval(linesRange.offset,
                 replaceWithEmptyLine:
                     lastToRemoveIsField && node is! FieldDeclaration);
           }
         }
       }

       // Remove nodes at the end of the widget class.
       if (replaceOffset != 0) {
         // Remove from the last node to keep, so remove empty lines.
         if (endOfLastNodeToKeep != 0) {
           replaceOffset = endOfLastNodeToKeep;
         }
         replaceInterval(widgetClass.rightBracket.offset,
             hasEmptyLineBeforeCreateState: endOfLastNodeToKeep != 0,
             hasEmptyLineAfterCreateState: false);
       }

       // Create the State subclass.
       builder.addInsertion(widgetClass.end, (builder) {
         builder.writeln();
         builder.writeln();

         builder.write('class $stateName$typeParams extends ');
         builder.writeReference(stateClass);

         // Write just param names (and not bounds, metadata and docs).
         builder.write('<${widgetClass.name}');
         if (typeParameters != null) {
           builder.write('<');
           var first = true;
           for (var param in typeParameters.typeParameters) {
             if (!first) {
               builder.write(', ');
               first = false;
             }
             builder.write(param.name.name);
           }
           builder.write('>');
         }

         builder.writeln('> {');

         var writeEmptyLine = false;
         for (var member in nodesToMove) {
           if (writeEmptyLine) {
             builder.writeln();
           }

           var comments = member.beginToken.precedingComments;
           if (comments != null) {
             var offset = utils.getLineContentStart(comments.offset);
             var length = comments.end - offset;
             builder.writeln(utils.getText(offset, length));
           }

           var text = rewriteWidgetMemberReferences(member);
           builder.write(text);
           // Write empty lines between members, but not before the first.
           writeEmptyLine = true;
         }

         builder.write('}');
       });
     });
   }

   /// Return an instance of this class. Used as a tear-off in `AssistProcessor`.
   static FlutterConvertToStatefulWidget newInstance() =>
       FlutterConvertToStatefulWidget();
 }

 class _FieldFinder extends RecursiveAstVisitor<void> {
   Set<FieldElement> fieldsAssignedInConstructors = {};

   @override
   void visitSimpleIdentifier(SimpleIdentifier node) {
     if (node.parent is FieldFormalParameter) {
       var element = node.staticElement;
       if (element is FieldFormalParameterElement) {
         var field = element.field;
         if (field != null) {
           fieldsAssignedInConstructors.add(field);
         }
       }
     }
     if (node.parent is ConstructorFieldInitializer) {
       var element = node.staticElement;
       if (element is FieldElement) {
         fieldsAssignedInConstructors.add(element);
       }
     }
     if (node.inSetterContext()) {
       var element = node.writeOrReadElement;
       if (element is PropertyAccessorElement) {
         var field = element.variable;
         if (field is FieldElement) {
           fieldsAssignedInConstructors.add(field);
         }
       }
     }
   }
 }

 class _ReplacementEditBuilder extends RecursiveAstVisitor<void> {
   final ClassElement widgetClassElement;

   final Set<Element> elementsToMove;

   final SourceRange linesRange;

   List<SourceEdit> edits = [];

   _ReplacementEditBuilder(
       this.widgetClassElement, this.elementsToMove, this.linesRange);

   @override
   void visitSimpleIdentifier(SimpleIdentifier node) {
     if (node.inDeclarationContext()) {
       return;
     }
     var element = node.staticElement;
     if (element is ExecutableElement &&
         element.enclosingElement == widgetClassElement &&
         !elementsToMove.contains(element)) {
       var offset = node.offset - linesRange.offset;
       var qualifier =
           element.isStatic ? widgetClassElement.displayName : 'widget';

       var parent = node.parent;
       if (parent is InterpolationExpression &&
           parent.leftBracket.type ==
               TokenType.STRING_INTERPOLATION_IDENTIFIER) {
         edits.add(SourceEdit(offset, 0, '{$qualifier.'));
         edits.add(SourceEdit(offset + node.length, 0, '}'));
       } else {
         edits.add(SourceEdit(offset, 0, '$qualifier.'));
       }
     }
   }
 }
	// 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/dart/ast/visitor.dart';
	import 'package:analyzer/dart/element/element.dart';
	import 'package:analyzer/source/source_range.dart';
	import 'package:analyzer/src/dart/ast/extensions.dart';
	import 'package:analyzer_plugin/protocol/protocol_common.dart' hide Element;
	import 'package:analyzer_plugin/utilities/assist/assist.dart';
	import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
	import 'package:analyzer_plugin/utilities/range_factory.dart';

	class FlutterConvertToStatefulWidget extends CorrectionProducer {
	@override
	AssistKind get assistKind =>
	DartAssistKind.FLUTTER_CONVERT_TO_STATEFUL_WIDGET;

	@override
	Future<void> compute(ChangeBuilder builder) async {
	var widgetClass = node.thisOrAncestorOfType<ClassDeclaration>();
	var superclass = widgetClass?.extendsClause?.superclass2;
	if (widgetClass == null \|\| superclass == null) {
	return;
	}

	// Don't spam, activate only from the `class` keyword to the class body.
	if (selectionOffset < widgetClass.classKeyword.offset \|\|
	selectionOffset > widgetClass.leftBracket.end) {
	return;
	}

	// Find the build() method.
	MethodDeclaration? buildMethod;
	for (var member in widgetClass.members) {
	if (member is MethodDeclaration && member.name.name == 'build') {
	var parameters = member.parameters;
	if (parameters != null && parameters.parameters.length == 1) {
	buildMethod = member;
	break;
	}
	}
	}
	if (buildMethod == null) {
	return;
	}

	// Must be a StatelessWidget subclasses.
	var widgetClassElement = widgetClass.declaredElement!;
	var superType = widgetClassElement.supertype;
	if (superType == null \|\| !flutter.isExactlyStatelessWidgetType(superType)) {
	return;
	}

	var widgetName = widgetClassElement.displayName;
	var stateName = widgetClassElement.isPrivate
	? '${widgetName}State'
	: '_${widgetName}State';

	// Find fields assigned in constructors.
	var visitor = _FieldFinder();
	for (var member in widgetClass.members) {
	if (member is ConstructorDeclaration) {
	member.accept(visitor);
	}
	}
	var fieldsAssignedInConstructors = visitor.fieldsAssignedInConstructors;

	// Prepare nodes to move.
	var nodesToMove = <ClassMember>{};
	var elementsToMove = <Element>{};
	for (var member in widgetClass.members) {
	if (member is FieldDeclaration && !member.isStatic) {
	for (var fieldNode in member.fields.variables) {
	var fieldElement = fieldNode.declaredElement as FieldElement;
	if (!fieldsAssignedInConstructors.contains(fieldElement)) {
	nodesToMove.add(member);
	elementsToMove.add(fieldElement);

	var getter = fieldElement.getter;
	if (getter != null) {
	elementsToMove.add(getter);
	}

	var setter = fieldElement.setter;
	if (setter != null) {
	elementsToMove.add(setter);
	}
	}
	}
	} else if (member is MethodDeclaration && !member.isStatic) {
	nodesToMove.add(member);
	elementsToMove.add(member.declaredElement!);
	}
	}

	/// Return the code for the [movedNode] which is suitable to be used
	/// inside the `State` class, so that references to the widget fields and
	/// methods, that are not moved, are qualified with the corresponding
	/// instance `widget.`, or static `MyWidgetClass.` qualifier.
	String rewriteWidgetMemberReferences(AstNode movedNode) {
	var linesRange = utils.getLinesRange(range.node(movedNode));
	var text = utils.getRangeText(linesRange);

	// Insert `widget.` before references to the widget instance members.
	var visitor = _ReplacementEditBuilder(
	widgetClassElement, elementsToMove, linesRange);
	movedNode.accept(visitor);
	return SourceEdit.applySequence(text, visitor.edits.reversed);
	}

	var statefulWidgetClass = await sessionHelper.getClass(
	flutter.widgetsUri,
	'StatefulWidget',
	);
	var stateClass = await sessionHelper.getClass(
	flutter.widgetsUri,
	'State',
	);
	if (statefulWidgetClass == null \|\| stateClass == null) {
	return;
	}

	await builder.addDartFileEdit(file, (builder) {
	builder.addReplacement(range.node(superclass), (builder) {
	builder.writeReference(statefulWidgetClass);
	});

	var replaceOffset = 0;
	var hasBuildMethod = false;

	var typeParams = '';
	var typeParameters = widgetClass.typeParameters;
	if (typeParameters != null) {
	typeParams = utils.getNodeText(typeParameters);
	}

	/// Replace code between [replaceOffset] and [replaceEnd] with
	/// `createState()`, empty line, or nothing.
	void replaceInterval(int replaceEnd,
	{bool replaceWithEmptyLine = false,
	bool hasEmptyLineBeforeCreateState = false,
	bool hasEmptyLineAfterCreateState = true}) {
	var replaceLength = replaceEnd - replaceOffset;
	builder.addReplacement(
	SourceRange(replaceOffset, replaceLength),
	(builder) {
	if (hasBuildMethod) {
	if (hasEmptyLineBeforeCreateState) {
	builder.writeln();
	}
	builder.writeln(' @override');
	builder.write(' ');
	builder.writeReference(stateClass);
	builder.write('<${widgetClass.name}$typeParams>');
	builder.writeln(' createState() => $stateName$typeParams();');
	if (hasEmptyLineAfterCreateState) {
	builder.writeln();
	}
	hasBuildMethod = false;
	} else if (replaceWithEmptyLine) {
	builder.writeln();
	}
	},
	);
	replaceOffset = 0;
	}

	// Remove continuous ranges of lines of nodes being moved.
	var lastToRemoveIsField = false;
	var endOfLastNodeToKeep = 0;
	for (var node in widgetClass.members) {
	if (nodesToMove.contains(node)) {
	if (replaceOffset == 0) {
	var comments = node.beginToken.precedingComments;
	var start = comments ?? node;
	replaceOffset = utils.getLineContentStart(start.offset);
	}
	if (node == buildMethod) {
	hasBuildMethod = true;
	}
	lastToRemoveIsField = node is FieldDeclaration;
	} else {
	var linesRange = utils.getLinesRange(range.node(node));
	endOfLastNodeToKeep = linesRange.end;
	if (replaceOffset != 0) {
	replaceInterval(linesRange.offset,
	replaceWithEmptyLine:
	lastToRemoveIsField && node is! FieldDeclaration);
	}
	}
	}

	// Remove nodes at the end of the widget class.
	if (replaceOffset != 0) {
	// Remove from the last node to keep, so remove empty lines.
	if (endOfLastNodeToKeep != 0) {
	replaceOffset = endOfLastNodeToKeep;
	}
	replaceInterval(widgetClass.rightBracket.offset,
	hasEmptyLineBeforeCreateState: endOfLastNodeToKeep != 0,
	hasEmptyLineAfterCreateState: false);
	}

	// Create the State subclass.
	builder.addInsertion(widgetClass.end, (builder) {
	builder.writeln();
	builder.writeln();

	builder.write('class $stateName$typeParams extends ');
	builder.writeReference(stateClass);

	// Write just param names (and not bounds, metadata and docs).
	builder.write('<${widgetClass.name}');
	if (typeParameters != null) {
	builder.write('<');
	var first = true;
	for (var param in typeParameters.typeParameters) {
	if (!first) {
	builder.write(', ');
	first = false;
	}
	builder.write(param.name.name);
	}
	builder.write('>');
	}

	builder.writeln('> {');

	var writeEmptyLine = false;
	for (var member in nodesToMove) {
	if (writeEmptyLine) {
	builder.writeln();
	}

	var comments = member.beginToken.precedingComments;
	if (comments != null) {
	var offset = utils.getLineContentStart(comments.offset);
	var length = comments.end - offset;
	builder.writeln(utils.getText(offset, length));
	}

	var text = rewriteWidgetMemberReferences(member);
	builder.write(text);
	// Write empty lines between members, but not before the first.
	writeEmptyLine = true;
	}

	builder.write('}');
	});
	});
	}

	/// Return an instance of this class. Used as a tear-off in `AssistProcessor`.
	static FlutterConvertToStatefulWidget newInstance() =>
	FlutterConvertToStatefulWidget();
	}

	class _FieldFinder extends RecursiveAstVisitor<void> {
	Set<FieldElement> fieldsAssignedInConstructors = {};

	@override
	void visitSimpleIdentifier(SimpleIdentifier node) {
	if (node.parent is FieldFormalParameter) {
	var element = node.staticElement;
	if (element is FieldFormalParameterElement) {
	var field = element.field;
	if (field != null) {
	fieldsAssignedInConstructors.add(field);
	}
	}
	}
	if (node.parent is ConstructorFieldInitializer) {
	var element = node.staticElement;
	if (element is FieldElement) {
	fieldsAssignedInConstructors.add(element);
	}
	}
	if (node.inSetterContext()) {
	var element = node.writeOrReadElement;
	if (element is PropertyAccessorElement) {
	var field = element.variable;
	if (field is FieldElement) {
	fieldsAssignedInConstructors.add(field);
	}
	}
	}
	}
	}

	class _ReplacementEditBuilder extends RecursiveAstVisitor<void> {
	final ClassElement widgetClassElement;

	final Set<Element> elementsToMove;

	final SourceRange linesRange;

	List<SourceEdit> edits = [];

	_ReplacementEditBuilder(
	this.widgetClassElement, this.elementsToMove, this.linesRange);

	@override
	void visitSimpleIdentifier(SimpleIdentifier node) {
	if (node.inDeclarationContext()) {
	return;
	}
	var element = node.staticElement;
	if (element is ExecutableElement &&
	element.enclosingElement == widgetClassElement &&
	!elementsToMove.contains(element)) {
	var offset = node.offset - linesRange.offset;
	var qualifier =
	element.isStatic ? widgetClassElement.displayName : 'widget';

	var parent = node.parent;
	if (parent is InterpolationExpression &&
	parent.leftBracket.type ==
	TokenType.STRING_INTERPOLATION_IDENTIFIER) {
	edits.add(SourceEdit(offset, 0, '{$qualifier.'));
	edits.add(SourceEdit(offset + node.length, 0, '}'));
	} else {
	edits.add(SourceEdit(offset, 0, '$qualifier.'));
	}
	}
	}
	}