pkg/analyzer_plugin/lib/src/utilities/change_builder/change_builder_core.dart - sdk.git - Git at Google

 // Copyright (c) 2017, 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 'dart:collection';

 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/analysis/session.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/src/utilities/change_builder/change_builder_dart.dart';
 import 'package:analyzer_plugin/src/utilities/change_builder/change_builder_yaml.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_yaml.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_workspace.dart';
 import 'package:yaml/yaml.dart';

 /// A builder used to build a [SourceChange].
 class ChangeBuilderImpl implements ChangeBuilder {
   /// The workspace in which the change builder should operate.
   final ChangeWorkspace workspace;

   /// The end-of-line marker used in the file being edited, or `null` if the
   /// default marker should be used.
   final String? eol;

   /// A table mapping group ids to the associated linked edit groups.
   final Map<String, LinkedEditGroup> _linkedEditGroups =
       <String, LinkedEditGroup>{};

   /// The source change selection or `null` if none.
   Position? _selection;

   /// The range of the selection for the change being built, or `null` if there
   /// is no selection.
   SourceRange? _selectionRange;

   /// The set of [Position]s that belong to the current [EditBuilderImpl] and
   /// should not be updated in result of inserting this builder.
   final Set<Position> _lockedPositions = HashSet<Position>.identity();

   /// A map of absolute normalized path to generic file edit builders.
   final Map<String, FileEditBuilderImpl> _genericFileEditBuilders = {};

   /// A map of absolute normalized path to Dart file edit builders.
   final Map<String, DartFileEditBuilderImpl> _dartFileEditBuilders = {};

   /// A map of absolute normalized path to YAML file edit builders.
   final Map<String, YamlFileEditBuilderImpl> _yamlFileEditBuilders = {};

   /// Initialize a newly created change builder. If the builder will be used to
   /// create changes for Dart files, then either a [session] or a [workspace]
   /// must be provided (but not both).
   ChangeBuilderImpl(
       {AnalysisSession? session, ChangeWorkspace? workspace, this.eol})
       : assert(session == null || workspace == null),
         workspace = workspace ?? _SingleSessionWorkspace(session!);

   /// Return a hash value that will change when new edits have been added to
   /// this builder.
   int get changeHash {
     // The hash value currently ignores edits to import directives because
     // finalizing the builders needs to happen exactly once and this getter
     // needs to be invoked repeatedly.
     //
     // In addition, we should consider implementing our own hash function for
     // file edits because the `hashCode` defined for them might not be
     // sufficient to detect all changes to the list of edits.
     return Object.hashAll([
       for (var builder in _genericFileEditBuilders.values)
         if (builder.hasEdits) builder.fileEdit,
       for (var builder in _dartFileEditBuilders.values)
         if (builder.hasEdits) builder.fileEdit,
       for (var builder in _yamlFileEditBuilders.values)
         if (builder.hasEdits) builder.fileEdit,
     ]);
   }

   @override
   SourceRange? get selectionRange => _selectionRange;

   @override
   SourceChange get sourceChange {
     var change = SourceChange('');
     for (var builder in _genericFileEditBuilders.values) {
       if (builder.hasEdits) {
         change.addFileEdit(builder.fileEdit);
         builder.finalize();
       }
     }
     for (var builder in _dartFileEditBuilders.values) {
       if (builder.hasEdits) {
         change.addFileEdit(builder.fileEdit);
         builder.finalize();
       }
     }
     for (var builder in _yamlFileEditBuilders.values) {
       if (builder.hasEdits) {
         change.addFileEdit(builder.fileEdit);
         builder.finalize();
       }
     }
     _linkedEditGroups.forEach((String name, LinkedEditGroup group) {
       change.addLinkedEditGroup(group);
     });
     var selection = _selection;
     if (selection != null) {
       change.selection = selection;
     }
     return change;
   }

   @override
   Future<void> addDartFileEdit(
       String path, void Function(DartFileEditBuilder builder) buildFileEdit,
       {ImportPrefixGenerator? importPrefixGenerator}) async {
     if (_genericFileEditBuilders.containsKey(path)) {
       throw StateError("Can't create both a generic file edit and a dart file "
           'edit for the same file');
     }
     if (_yamlFileEditBuilders.containsKey(path)) {
       throw StateError("Can't create both a yaml file edit and a dart file "
           'edit for the same file');
     }
     var builder = _dartFileEditBuilders[path];
     if (builder == null) {
       builder = await _createDartFileEditBuilder(path);
       if (builder != null) {
         // It's not currently supported to call this method twice concurrently
         // for the same file as two builder may be produced because of the above
         // `await` so detect this and throw to avoid losing edits.
         if (_dartFileEditBuilders.containsKey(path)) {
           throw StateError(
               "Can't add multiple edits concurrently for the same file");
         }
         _dartFileEditBuilders[path] = builder;
       }
     }
     if (builder != null) {
       builder.importPrefixGenerator = importPrefixGenerator;
       buildFileEdit(builder);
     }
   }

   @override
   Future<void> addGenericFileEdit(
       String path, void Function(FileEditBuilder builder) buildFileEdit) async {
     if (_dartFileEditBuilders.containsKey(path)) {
       throw StateError("Can't create both a dart file edit and a generic file "
           'edit for the same file');
     }
     if (_yamlFileEditBuilders.containsKey(path)) {
       throw StateError("Can't create both a yaml file edit and a generic file "
           'edit for the same file');
     }
     var builder = _genericFileEditBuilders[path];
     if (builder == null) {
       builder = FileEditBuilderImpl(this, path, 0);
       _genericFileEditBuilders[path] = builder;
     }
     buildFileEdit(builder);
   }

   @override
   Future<void> addYamlFileEdit(String path,
       void Function(YamlFileEditBuilder builder) buildFileEdit) async {
     if (_dartFileEditBuilders.containsKey(path)) {
       throw StateError("Can't create both a dart file edit and a yaml file "
           'edit for the same file');
     }
     if (_genericFileEditBuilders.containsKey(path)) {
       throw StateError("Can't create both a generic file edit and a yaml file "
           'edit for the same file');
     }
     var builder = _yamlFileEditBuilders[path];
     if (builder == null) {
       builder = YamlFileEditBuilderImpl(
           this,
           path,
           loadYamlDocument(
               workspace
                   .getSession(path)!
                   .resourceProvider
                   .getFile(path)
                   .readAsStringSync(),
               recover: true),
           0);
       _yamlFileEditBuilders[path] = builder;
     }
     buildFileEdit(builder);
   }

   @override
   ChangeBuilder copy() {
     var copy = ChangeBuilderImpl(workspace: workspace, eol: eol);
     for (var entry in _linkedEditGroups.entries) {
       copy._linkedEditGroups[entry.key] = _copyLinkedEditGroup(entry.value);
     }
     var selection = _selection;
     if (selection != null) {
       copy._selection = _copyPosition(selection);
     }
     copy._selectionRange = _selectionRange;
     copy._lockedPositions.addAll(_lockedPositions);
     for (var entry in _genericFileEditBuilders.entries) {
       copy._genericFileEditBuilders[entry.key] = entry.value.copyWith(copy);
     }
     //
     // The file edit builders for libraries (those whose [libraryChangeBuilder]
     // is `null`) are copied first so that the copies exist when we copy the
     // builders for parts and the structure can be preserved.
     //
     var editBuilderMap = <DartFileEditBuilderImpl, DartFileEditBuilderImpl>{};
     for (var entry in _dartFileEditBuilders.entries) {
       var oldBuilder = entry.value;
       if (oldBuilder.libraryChangeBuilder == null) {
         var newBuilder = oldBuilder.copyWith(copy);
         copy._dartFileEditBuilders[entry.key] = newBuilder;
         editBuilderMap[oldBuilder] = newBuilder;
       }
     }
     for (var entry in _dartFileEditBuilders.entries) {
       var oldBuilder = entry.value;
       if (oldBuilder.libraryChangeBuilder != null) {
         var newBuilder =
             oldBuilder.copyWith(copy, editBuilderMap: editBuilderMap);
         copy._dartFileEditBuilders[entry.key] = newBuilder;
       }
     }
     for (var entry in _yamlFileEditBuilders.entries) {
       copy._yamlFileEditBuilders[entry.key] = entry.value.copyWith(copy);
     }
     return copy;
   }

   /// Return the linked edit group with the given [groupName], creating it if it
   /// did not already exist.
   LinkedEditGroup getLinkedEditGroup(String groupName) {
     var group = _linkedEditGroups[groupName];
     if (group == null) {
       group = LinkedEditGroup.empty();
       _linkedEditGroups[groupName] = group;
     }
     return group;
   }

   @override
   bool hasEditsFor(String path) {
     return _dartFileEditBuilders.containsKey(path) ||
         _genericFileEditBuilders.containsKey(path) ||
         _yamlFileEditBuilders.containsKey(path);
   }

   @override
   void setSelection(Position position) {
     _selection = position;
   }

   /// Return a copy of the linked edit [group].
   LinkedEditGroup _copyLinkedEditGroup(LinkedEditGroup group) {
     return LinkedEditGroup(group.positions.map(_copyPosition).toList(),
         group.length, group.suggestions.toList());
   }

   /// Return a copy of the [position].
   Position _copyPosition(Position position) {
     return Position(position.file, position.offset);
   }

   /// Create and return a [DartFileEditBuilder] that can be used to build edits
   /// to the Dart file with the given [path].
   Future<DartFileEditBuilderImpl?> _createDartFileEditBuilder(
       String? path) async {
     if (path == null || !(workspace.containsFile(path) ?? false)) {
       return null;
     }

     var session = workspace.getSession(path);
     var result = await session?.getResolvedUnit(path);
     if (result is! ResolvedUnitResult) {
       throw AnalysisException('Cannot analyze "$path"');
     }
     var timeStamp = result.exists ? 0 : -1;

     var declaredUnit = result.unit.declaredElement;
     var libraryUnit = declaredUnit?.library.definingCompilationUnit;

     DartFileEditBuilderImpl? libraryEditBuilder;
     if (libraryUnit != null && libraryUnit != declaredUnit) {
       // If the receiver is a part file builder, then proactively cache the
       // library file builder so that imports can be finalized synchronously.
       await addDartFileEdit(libraryUnit.source.fullName, (builder) {
         libraryEditBuilder = builder as DartFileEditBuilderImpl;
       });
     }

     return DartFileEditBuilderImpl(this, result, timeStamp, libraryEditBuilder);
   }

   void _setSelectionRange(SourceRange range) {
     _selectionRange = range;
   }

   /// Update the offsets of any positions that occur at or after the given
   /// [offset] such that the positions are offset by the given [delta].
   /// Positions occur in linked edit groups and as the post-change selection.
   void _updatePositions(int offset, int delta) {
     void _updatePosition(Position position) {
       if (position.offset >= offset && !_lockedPositions.contains(position)) {
         position.offset = position.offset + delta;
       }
     }

     for (var group in _linkedEditGroups.values) {
       for (var position in group.positions) {
         _updatePosition(position);
       }
     }
     var selection = _selection;
     if (selection != null) {
       _updatePosition(selection);
     }
   }
 }

 /// A builder used to build a [SourceEdit] as part of a [SourceFileEdit].
 class EditBuilderImpl implements EditBuilder {
   /// The builder being used to create the source file edit of which the source
   /// edit will be a part.
   final FileEditBuilderImpl fileEditBuilder;

   /// The offset of the region being replaced.
   final int offset;

   /// The length of the region being replaced.
   final int length;

   /// The range of the selection for the change being built, or `null` if the
   /// selection is not inside the change being built.
   SourceRange? _selectionRange;

   /// The end-of-line marker used in the file being edited, or `null` if the
   /// default marker should be used.
   String? _eol;

   /// The buffer in which the content of the edit is being composed.
   final StringBuffer _buffer = StringBuffer();

   /// Initialize a newly created builder to build a source edit.
   EditBuilderImpl(this.fileEditBuilder, this.offset, this.length) {
     _eol = fileEditBuilder.changeBuilder.eol;
   }

   /// Create and return an edit representing the replacement of a region of the
   /// file with the accumulated text.
   SourceEdit get sourceEdit => SourceEdit(offset, length, _buffer.toString());

   @override
   void addLinkedEdit(String groupName,
       void Function(LinkedEditBuilder builder) buildLinkedEdit) {
     var builder = createLinkedEditBuilder();
     var start = offset + _buffer.length;
     try {
       buildLinkedEdit(builder);
     } finally {
       var end = offset + _buffer.length;
       var length = end - start;
       if (length != 0) {
         var position = Position(fileEditBuilder.fileEdit.file, start);
         fileEditBuilder.changeBuilder._lockedPositions.add(position);
         var group = fileEditBuilder.changeBuilder.getLinkedEditGroup(groupName);
         group.addPosition(position, length);
         for (var suggestion in builder.suggestions) {
           group.addSuggestion(suggestion);
         }
       }
     }
   }

   @override
   void addSimpleLinkedEdit(String groupName, String text,
       {LinkedEditSuggestionKind? kind, List<String>? suggestions}) {
     addLinkedEdit(groupName, (LinkedEditBuilder builder) {
       builder.write(text);
       if (kind != null && suggestions != null) {
         for (var suggestion in suggestions) {
           builder.addSuggestion(kind, suggestion);
         }
       } else if (kind != null || suggestions != null) {
         throw ArgumentError(
             'Either both kind and suggestions must be provided or neither.');
       }
     });
   }

   LinkedEditBuilderImpl createLinkedEditBuilder() {
     return LinkedEditBuilderImpl(this);
   }

   @override
   void selectAll(void Function() writer) {
     var rangeOffset = _buffer.length;
     writer();
     var rangeLength = _buffer.length - rangeOffset;
     _selectionRange = SourceRange(offset + rangeOffset, rangeLength);
   }

   @override
   void selectHere() {
     _selectionRange = SourceRange(offset + _buffer.length, 0);
   }

   @override
   void write(String string) {
     _buffer.write(string);
   }

   @override
   void writeln([String? string]) {
     if (string != null) {
       _buffer.write(string);
     }
     if (_eol == null) {
       _buffer.writeln();
     } else {
       _buffer.write(_eol);
     }
   }
 }

 /// A builder used to build a [SourceFileEdit] within a [SourceChange].
 class FileEditBuilderImpl implements FileEditBuilder {
   /// The builder being used to create the source change of which the source
   /// file edit will be a part.
   final ChangeBuilderImpl changeBuilder;

   /// The source file edit that is being built.
   final SourceFileEdit fileEdit;

   /// Initialize a newly created builder to build a source file edit within the
   /// change being built by the given [changeBuilder]. The file being edited has
   /// the given absolute [path] and [timeStamp].
   FileEditBuilderImpl(this.changeBuilder, String path, int timeStamp)
       : fileEdit = SourceFileEdit(path, timeStamp);

   /// Return `true` if this builder has edits to be applied.
   bool get hasEdits => fileEdit.edits.isNotEmpty;

   @override
   void addDeletion(SourceRange range) {
     if (range.length > 0) {
       var builder = createEditBuilder(range.offset, range.length);
       _addEditBuilder(builder);
     }
   }

   @override
   void addInsertion(int offset, void Function(EditBuilder builder) buildEdit) {
     var builder = createEditBuilder(offset, 0);
     try {
       buildEdit(builder);
     } finally {
       _addEditBuilder(builder);
     }
   }

   @override
   void addLinkedPosition(SourceRange range, String groupName) {
     var group = changeBuilder.getLinkedEditGroup(groupName);
     var position =
         Position(fileEdit.file, range.offset + _deltaToOffset(range.offset));
     group.addPosition(position, range.length);
   }

   @override
   void addReplacement(
       SourceRange range, void Function(EditBuilder builder) buildEdit) {
     var builder = createEditBuilder(range.offset, range.length);
     try {
       buildEdit(builder);
     } finally {
       _addEditBuilder(builder);
     }
   }

   @override
   void addSimpleInsertion(int offset, String text) {
     var builder = createEditBuilder(offset, 0);
     try {
       builder.write(text);
     } finally {
       _addEditBuilder(builder);
     }
   }

   @override
   void addSimpleReplacement(SourceRange range, String text) {
     var builder = createEditBuilder(range.offset, range.length);
     try {
       builder.write(text);
     } finally {
       _addEditBuilder(builder);
     }
   }

   FileEditBuilderImpl copyWith(ChangeBuilderImpl changeBuilder) {
     var copy =
         FileEditBuilderImpl(changeBuilder, fileEdit.file, fileEdit.fileStamp);
     copy.fileEdit.edits.addAll(fileEdit.edits);
     return copy;
   }

   EditBuilderImpl createEditBuilder(int offset, int length) {
     return EditBuilderImpl(this, offset, length);
   }

   /// Finalize the source file edit that is being built.
   void finalize() {
     // Nothing to do.
   }

   /// Replace edits in the [range] with the given [edit].
   /// The [range] is relative to the original code.
   void replaceEdits(SourceRange range, SourceEdit edit) {
     fileEdit.edits.removeWhere((edit) {
       if (range.contains(edit.offset)) {
         if (!range.contains(edit.end)) {
           throw StateError('$edit is not completely in $range');
         }
         return true;
       } else if (range.contains(edit.end)) {
         throw StateError('$edit is not completely in $range');
       }
       return false;
     });

     _addEdit(edit);
   }

   /// Add the edit from the given [edit] to the edits associated with the
   /// current file.
   void _addEdit(SourceEdit edit) {
     fileEdit.add(edit);
     var delta = _editDelta(edit);
     changeBuilder._updatePositions(edit.offset, delta);
     changeBuilder._lockedPositions.clear();
   }

   /// Add the edit from the given [builder] to the edits associated with the
   /// current file.
   void _addEditBuilder(EditBuilderImpl builder) {
     var edit = builder.sourceEdit;
     _addEdit(edit);
     _captureSelection(builder, edit);
   }

   /// Capture the selection offset if one was set.
   void _captureSelection(EditBuilderImpl builder, SourceEdit edit) {
     var range = builder._selectionRange;
     if (range != null) {
       var position = Position(fileEdit.file, range.offset + _deltaToEdit(edit));
       changeBuilder.setSelection(position);
       changeBuilder._setSelectionRange(range);
     }
   }

   /// Return the current delta caused by edits that will be applied before the
   /// [targetEdit]. In other words, if all of the edits that occur before the
   /// target edit were to be applied, then the text at the offset of the target
   /// edit before the applied edits will be at `offset + _deltaToOffset(offset)`
   /// after the edits.
   int _deltaToEdit(SourceEdit targetEdit) {
     var delta = 0;
     for (var edit in fileEdit.edits) {
       if (edit.offset < targetEdit.offset) {
         delta += _editDelta(edit);
       }
     }
     return delta;
   }

   /// Return the current delta caused by edits that will be applied before the
   /// given [offset]. In other words, if all of the edits that have so far been
   /// added were to be applied, then the text at the given `offset` before the
   /// applied edits will be at `offset + _deltaToOffset(offset)` after the
   /// edits.
   int _deltaToOffset(int offset) {
     var delta = 0;
     for (var edit in fileEdit.edits) {
       if (edit.offset <= offset) {
         delta += _editDelta(edit);
       }
     }
     return delta;
   }

   /// Return the delta introduced by the given `edit`.
   int _editDelta(SourceEdit edit) => edit.replacement.length - edit.length;
 }

 /// A builder used to build a [LinkedEdit] region within an edit.
 class LinkedEditBuilderImpl implements LinkedEditBuilder {
   final EditBuilderImpl editBuilder;

   final List<LinkedEditSuggestion> suggestions = <LinkedEditSuggestion>[];

   LinkedEditBuilderImpl(this.editBuilder);

   @override
   void addSuggestion(LinkedEditSuggestionKind kind, String value) {
     suggestions.add(LinkedEditSuggestion(value, kind));
   }

   @override
   void addSuggestions(LinkedEditSuggestionKind kind, Iterable<String> values) {
     values.forEach((value) => addSuggestion(kind, value));
   }

   @override
   void write(String string) {
     editBuilder.write(string);
   }

   @override
   void writeln([String? string]) {
     editBuilder.writeln(string);
   }
 }

 /// Workspace that wraps a single [AnalysisSession].
 class _SingleSessionWorkspace extends ChangeWorkspace {
   final AnalysisSession session;

   _SingleSessionWorkspace(this.session);

   @override
   ResourceProvider get resourceProvider => session.resourceProvider;

   @override
   bool? containsFile(String path) {
     var analysisContext = session.analysisContext;
     return analysisContext.contextRoot.isAnalyzed(path);
   }

   @override
   AnalysisSession? getSession(String path) {
     if (containsFile(path) ?? false) {
       return session;
     }
     throw StateError('Not in a context root: $path');
   }
 }
	// Copyright (c) 2017, 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 'dart:collection';

	import 'package:analyzer/dart/analysis/results.dart';
	import 'package:analyzer/dart/analysis/session.dart';
	import 'package:analyzer/exception/exception.dart';
	import 'package:analyzer/file_system/file_system.dart';
	import 'package:analyzer/src/generated/source.dart';
	import 'package:analyzer_plugin/protocol/protocol_common.dart';
	import 'package:analyzer_plugin/src/utilities/change_builder/change_builder_dart.dart';
	import 'package:analyzer_plugin/src/utilities/change_builder/change_builder_yaml.dart';
	import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
	import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
	import 'package:analyzer_plugin/utilities/change_builder/change_builder_yaml.dart';
	import 'package:analyzer_plugin/utilities/change_builder/change_workspace.dart';
	import 'package:yaml/yaml.dart';

	/// A builder used to build a [SourceChange].
	class ChangeBuilderImpl implements ChangeBuilder {
	/// The workspace in which the change builder should operate.
	final ChangeWorkspace workspace;

	/// The end-of-line marker used in the file being edited, or `null` if the
	/// default marker should be used.
	final String? eol;

	/// A table mapping group ids to the associated linked edit groups.
	final Map<String, LinkedEditGroup> _linkedEditGroups =
	<String, LinkedEditGroup>{};

	/// The source change selection or `null` if none.
	Position? _selection;

	/// The range of the selection for the change being built, or `null` if there
	/// is no selection.
	SourceRange? _selectionRange;

	/// The set of [Position]s that belong to the current [EditBuilderImpl] and
	/// should not be updated in result of inserting this builder.
	final Set<Position> _lockedPositions = HashSet<Position>.identity();

	/// A map of absolute normalized path to generic file edit builders.
	final Map<String, FileEditBuilderImpl> _genericFileEditBuilders = {};

	/// A map of absolute normalized path to Dart file edit builders.
	final Map<String, DartFileEditBuilderImpl> _dartFileEditBuilders = {};

	/// A map of absolute normalized path to YAML file edit builders.
	final Map<String, YamlFileEditBuilderImpl> _yamlFileEditBuilders = {};

	/// Initialize a newly created change builder. If the builder will be used to
	/// create changes for Dart files, then either a [session] or a [workspace]
	/// must be provided (but not both).
	ChangeBuilderImpl(
	{AnalysisSession? session, ChangeWorkspace? workspace, this.eol})
	: assert(session == null \|\| workspace == null),
	workspace = workspace ?? _SingleSessionWorkspace(session!);

	/// Return a hash value that will change when new edits have been added to
	/// this builder.
	int get changeHash {
	// The hash value currently ignores edits to import directives because
	// finalizing the builders needs to happen exactly once and this getter
	// needs to be invoked repeatedly.
	//
	// In addition, we should consider implementing our own hash function for
	// file edits because the `hashCode` defined for them might not be
	// sufficient to detect all changes to the list of edits.
	return Object.hashAll([
	for (var builder in _genericFileEditBuilders.values)
	if (builder.hasEdits) builder.fileEdit,
	for (var builder in _dartFileEditBuilders.values)
	if (builder.hasEdits) builder.fileEdit,
	for (var builder in _yamlFileEditBuilders.values)
	if (builder.hasEdits) builder.fileEdit,
	]);
	}

	@override
	SourceRange? get selectionRange => _selectionRange;

	@override
	SourceChange get sourceChange {
	var change = SourceChange('');
	for (var builder in _genericFileEditBuilders.values) {
	if (builder.hasEdits) {
	change.addFileEdit(builder.fileEdit);
	builder.finalize();
	}
	}
	for (var builder in _dartFileEditBuilders.values) {
	if (builder.hasEdits) {
	change.addFileEdit(builder.fileEdit);
	builder.finalize();
	}
	}
	for (var builder in _yamlFileEditBuilders.values) {
	if (builder.hasEdits) {
	change.addFileEdit(builder.fileEdit);
	builder.finalize();
	}
	}
	_linkedEditGroups.forEach((String name, LinkedEditGroup group) {
	change.addLinkedEditGroup(group);
	});
	var selection = _selection;
	if (selection != null) {
	change.selection = selection;
	}
	return change;
	}

	@override
	Future<void> addDartFileEdit(
	String path, void Function(DartFileEditBuilder builder) buildFileEdit,
	{ImportPrefixGenerator? importPrefixGenerator}) async {
	if (_genericFileEditBuilders.containsKey(path)) {
	throw StateError("Can't create both a generic file edit and a dart file "
	'edit for the same file');
	}
	if (_yamlFileEditBuilders.containsKey(path)) {
	throw StateError("Can't create both a yaml file edit and a dart file "
	'edit for the same file');
	}
	var builder = _dartFileEditBuilders[path];
	if (builder == null) {
	builder = await _createDartFileEditBuilder(path);
	if (builder != null) {
	// It's not currently supported to call this method twice concurrently
	// for the same file as two builder may be produced because of the above
	// `await` so detect this and throw to avoid losing edits.
	if (_dartFileEditBuilders.containsKey(path)) {
	throw StateError(
	"Can't add multiple edits concurrently for the same file");
	}
	_dartFileEditBuilders[path] = builder;
	}
	}
	if (builder != null) {
	builder.importPrefixGenerator = importPrefixGenerator;
	buildFileEdit(builder);
	}
	}

	@override
	Future<void> addGenericFileEdit(
	String path, void Function(FileEditBuilder builder) buildFileEdit) async {
	if (_dartFileEditBuilders.containsKey(path)) {
	throw StateError("Can't create both a dart file edit and a generic file "
	'edit for the same file');
	}
	if (_yamlFileEditBuilders.containsKey(path)) {
	throw StateError("Can't create both a yaml file edit and a generic file "
	'edit for the same file');
	}
	var builder = _genericFileEditBuilders[path];
	if (builder == null) {
	builder = FileEditBuilderImpl(this, path, 0);
	_genericFileEditBuilders[path] = builder;
	}
	buildFileEdit(builder);
	}

	@override
	Future<void> addYamlFileEdit(String path,
	void Function(YamlFileEditBuilder builder) buildFileEdit) async {
	if (_dartFileEditBuilders.containsKey(path)) {
	throw StateError("Can't create both a dart file edit and a yaml file "
	'edit for the same file');
	}
	if (_genericFileEditBuilders.containsKey(path)) {
	throw StateError("Can't create both a generic file edit and a yaml file "
	'edit for the same file');
	}
	var builder = _yamlFileEditBuilders[path];
	if (builder == null) {
	builder = YamlFileEditBuilderImpl(
	this,
	path,
	loadYamlDocument(
	workspace
	.getSession(path)!
	.resourceProvider
	.getFile(path)
	.readAsStringSync(),
	recover: true),
	0);
	_yamlFileEditBuilders[path] = builder;
	}
	buildFileEdit(builder);
	}

	@override
	ChangeBuilder copy() {
	var copy = ChangeBuilderImpl(workspace: workspace, eol: eol);
	for (var entry in _linkedEditGroups.entries) {
	copy._linkedEditGroups[entry.key] = _copyLinkedEditGroup(entry.value);
	}
	var selection = _selection;
	if (selection != null) {
	copy._selection = _copyPosition(selection);
	}
	copy._selectionRange = _selectionRange;
	copy._lockedPositions.addAll(_lockedPositions);
	for (var entry in _genericFileEditBuilders.entries) {
	copy._genericFileEditBuilders[entry.key] = entry.value.copyWith(copy);
	}
	//
	// The file edit builders for libraries (those whose [libraryChangeBuilder]
	// is `null`) are copied first so that the copies exist when we copy the
	// builders for parts and the structure can be preserved.
	//
	var editBuilderMap = <DartFileEditBuilderImpl, DartFileEditBuilderImpl>{};
	for (var entry in _dartFileEditBuilders.entries) {
	var oldBuilder = entry.value;
	if (oldBuilder.libraryChangeBuilder == null) {
	var newBuilder = oldBuilder.copyWith(copy);
	copy._dartFileEditBuilders[entry.key] = newBuilder;
	editBuilderMap[oldBuilder] = newBuilder;
	}
	}
	for (var entry in _dartFileEditBuilders.entries) {
	var oldBuilder = entry.value;
	if (oldBuilder.libraryChangeBuilder != null) {
	var newBuilder =
	oldBuilder.copyWith(copy, editBuilderMap: editBuilderMap);
	copy._dartFileEditBuilders[entry.key] = newBuilder;
	}
	}
	for (var entry in _yamlFileEditBuilders.entries) {
	copy._yamlFileEditBuilders[entry.key] = entry.value.copyWith(copy);
	}
	return copy;
	}

	/// Return the linked edit group with the given [groupName], creating it if it
	/// did not already exist.
	LinkedEditGroup getLinkedEditGroup(String groupName) {
	var group = _linkedEditGroups[groupName];
	if (group == null) {
	group = LinkedEditGroup.empty();
	_linkedEditGroups[groupName] = group;
	}
	return group;
	}

	@override
	bool hasEditsFor(String path) {
	return _dartFileEditBuilders.containsKey(path) \|\|
	_genericFileEditBuilders.containsKey(path) \|\|
	_yamlFileEditBuilders.containsKey(path);
	}

	@override
	void setSelection(Position position) {
	_selection = position;
	}

	/// Return a copy of the linked edit [group].
	LinkedEditGroup _copyLinkedEditGroup(LinkedEditGroup group) {
	return LinkedEditGroup(group.positions.map(_copyPosition).toList(),
	group.length, group.suggestions.toList());
	}

	/// Return a copy of the [position].
	Position _copyPosition(Position position) {
	return Position(position.file, position.offset);
	}

	/// Create and return a [DartFileEditBuilder] that can be used to build edits
	/// to the Dart file with the given [path].
	Future<DartFileEditBuilderImpl?> _createDartFileEditBuilder(
	String? path) async {
	if (path == null \|\| !(workspace.containsFile(path) ?? false)) {
	return null;
	}

	var session = workspace.getSession(path);
	var result = await session?.getResolvedUnit(path);
	if (result is! ResolvedUnitResult) {
	throw AnalysisException('Cannot analyze "$path"');
	}
	var timeStamp = result.exists ? 0 : -1;

	var declaredUnit = result.unit.declaredElement;
	var libraryUnit = declaredUnit?.library.definingCompilationUnit;

	DartFileEditBuilderImpl? libraryEditBuilder;
	if (libraryUnit != null && libraryUnit != declaredUnit) {
	// If the receiver is a part file builder, then proactively cache the
	// library file builder so that imports can be finalized synchronously.
	await addDartFileEdit(libraryUnit.source.fullName, (builder) {
	libraryEditBuilder = builder as DartFileEditBuilderImpl;
	});
	}

	return DartFileEditBuilderImpl(this, result, timeStamp, libraryEditBuilder);
	}

	void _setSelectionRange(SourceRange range) {
	_selectionRange = range;
	}

	/// Update the offsets of any positions that occur at or after the given
	/// [offset] such that the positions are offset by the given [delta].
	/// Positions occur in linked edit groups and as the post-change selection.
	void _updatePositions(int offset, int delta) {
	void _updatePosition(Position position) {
	if (position.offset >= offset && !_lockedPositions.contains(position)) {
	position.offset = position.offset + delta;
	}
	}

	for (var group in _linkedEditGroups.values) {
	for (var position in group.positions) {
	_updatePosition(position);
	}
	}
	var selection = _selection;
	if (selection != null) {
	_updatePosition(selection);
	}
	}
	}

	/// A builder used to build a [SourceEdit] as part of a [SourceFileEdit].
	class EditBuilderImpl implements EditBuilder {
	/// The builder being used to create the source file edit of which the source
	/// edit will be a part.
	final FileEditBuilderImpl fileEditBuilder;

	/// The offset of the region being replaced.
	final int offset;

	/// The length of the region being replaced.
	final int length;

	/// The range of the selection for the change being built, or `null` if the
	/// selection is not inside the change being built.
	SourceRange? _selectionRange;

	/// The end-of-line marker used in the file being edited, or `null` if the
	/// default marker should be used.
	String? _eol;

	/// The buffer in which the content of the edit is being composed.
	final StringBuffer _buffer = StringBuffer();

	/// Initialize a newly created builder to build a source edit.
	EditBuilderImpl(this.fileEditBuilder, this.offset, this.length) {
	_eol = fileEditBuilder.changeBuilder.eol;
	}

	/// Create and return an edit representing the replacement of a region of the
	/// file with the accumulated text.
	SourceEdit get sourceEdit => SourceEdit(offset, length, _buffer.toString());

	@override
	void addLinkedEdit(String groupName,
	void Function(LinkedEditBuilder builder) buildLinkedEdit) {
	var builder = createLinkedEditBuilder();
	var start = offset + _buffer.length;
	try {
	buildLinkedEdit(builder);
	} finally {
	var end = offset + _buffer.length;
	var length = end - start;
	if (length != 0) {
	var position = Position(fileEditBuilder.fileEdit.file, start);
	fileEditBuilder.changeBuilder._lockedPositions.add(position);
	var group = fileEditBuilder.changeBuilder.getLinkedEditGroup(groupName);
	group.addPosition(position, length);
	for (var suggestion in builder.suggestions) {
	group.addSuggestion(suggestion);
	}
	}
	}
	}

	@override
	void addSimpleLinkedEdit(String groupName, String text,
	{LinkedEditSuggestionKind? kind, List<String>? suggestions}) {
	addLinkedEdit(groupName, (LinkedEditBuilder builder) {
	builder.write(text);
	if (kind != null && suggestions != null) {
	for (var suggestion in suggestions) {
	builder.addSuggestion(kind, suggestion);
	}
	} else if (kind != null \|\| suggestions != null) {
	throw ArgumentError(
	'Either both kind and suggestions must be provided or neither.');
	}
	});
	}

	LinkedEditBuilderImpl createLinkedEditBuilder() {
	return LinkedEditBuilderImpl(this);
	}

	@override
	void selectAll(void Function() writer) {
	var rangeOffset = _buffer.length;
	writer();
	var rangeLength = _buffer.length - rangeOffset;
	_selectionRange = SourceRange(offset + rangeOffset, rangeLength);
	}

	@override
	void selectHere() {
	_selectionRange = SourceRange(offset + _buffer.length, 0);
	}

	@override
	void write(String string) {
	_buffer.write(string);
	}

	@override
	void writeln([String? string]) {
	if (string != null) {
	_buffer.write(string);
	}
	if (_eol == null) {
	_buffer.writeln();
	} else {
	_buffer.write(_eol);
	}
	}
	}

	/// A builder used to build a [SourceFileEdit] within a [SourceChange].
	class FileEditBuilderImpl implements FileEditBuilder {
	/// The builder being used to create the source change of which the source
	/// file edit will be a part.
	final ChangeBuilderImpl changeBuilder;

	/// The source file edit that is being built.
	final SourceFileEdit fileEdit;

	/// Initialize a newly created builder to build a source file edit within the
	/// change being built by the given [changeBuilder]. The file being edited has
	/// the given absolute [path] and [timeStamp].
	FileEditBuilderImpl(this.changeBuilder, String path, int timeStamp)
	: fileEdit = SourceFileEdit(path, timeStamp);

	/// Return `true` if this builder has edits to be applied.
	bool get hasEdits => fileEdit.edits.isNotEmpty;

	@override
	void addDeletion(SourceRange range) {
	if (range.length > 0) {
	var builder = createEditBuilder(range.offset, range.length);
	_addEditBuilder(builder);
	}
	}

	@override
	void addInsertion(int offset, void Function(EditBuilder builder) buildEdit) {
	var builder = createEditBuilder(offset, 0);
	try {
	buildEdit(builder);
	} finally {
	_addEditBuilder(builder);
	}
	}

	@override
	void addLinkedPosition(SourceRange range, String groupName) {
	var group = changeBuilder.getLinkedEditGroup(groupName);
	var position =
	Position(fileEdit.file, range.offset + _deltaToOffset(range.offset));
	group.addPosition(position, range.length);
	}

	@override
	void addReplacement(
	SourceRange range, void Function(EditBuilder builder) buildEdit) {
	var builder = createEditBuilder(range.offset, range.length);
	try {
	buildEdit(builder);
	} finally {
	_addEditBuilder(builder);
	}
	}

	@override
	void addSimpleInsertion(int offset, String text) {
	var builder = createEditBuilder(offset, 0);
	try {
	builder.write(text);
	} finally {
	_addEditBuilder(builder);
	}
	}

	@override
	void addSimpleReplacement(SourceRange range, String text) {
	var builder = createEditBuilder(range.offset, range.length);
	try {
	builder.write(text);
	} finally {
	_addEditBuilder(builder);
	}
	}

	FileEditBuilderImpl copyWith(ChangeBuilderImpl changeBuilder) {
	var copy =
	FileEditBuilderImpl(changeBuilder, fileEdit.file, fileEdit.fileStamp);
	copy.fileEdit.edits.addAll(fileEdit.edits);
	return copy;
	}

	EditBuilderImpl createEditBuilder(int offset, int length) {
	return EditBuilderImpl(this, offset, length);
	}

	/// Finalize the source file edit that is being built.
	void finalize() {
	// Nothing to do.
	}

	/// Replace edits in the [range] with the given [edit].
	/// The [range] is relative to the original code.
	void replaceEdits(SourceRange range, SourceEdit edit) {
	fileEdit.edits.removeWhere((edit) {
	if (range.contains(edit.offset)) {
	if (!range.contains(edit.end)) {
	throw StateError('$edit is not completely in $range');
	}
	return true;
	} else if (range.contains(edit.end)) {
	throw StateError('$edit is not completely in $range');
	}
	return false;
	});

	_addEdit(edit);
	}

	/// Add the edit from the given [edit] to the edits associated with the
	/// current file.
	void _addEdit(SourceEdit edit) {
	fileEdit.add(edit);
	var delta = _editDelta(edit);
	changeBuilder._updatePositions(edit.offset, delta);
	changeBuilder._lockedPositions.clear();
	}

	/// Add the edit from the given [builder] to the edits associated with the
	/// current file.
	void _addEditBuilder(EditBuilderImpl builder) {
	var edit = builder.sourceEdit;
	_addEdit(edit);
	_captureSelection(builder, edit);
	}

	/// Capture the selection offset if one was set.
	void _captureSelection(EditBuilderImpl builder, SourceEdit edit) {
	var range = builder._selectionRange;
	if (range != null) {
	var position = Position(fileEdit.file, range.offset + _deltaToEdit(edit));
	changeBuilder.setSelection(position);
	changeBuilder._setSelectionRange(range);
	}
	}

	/// Return the current delta caused by edits that will be applied before the
	/// [targetEdit]. In other words, if all of the edits that occur before the
	/// target edit were to be applied, then the text at the offset of the target
	/// edit before the applied edits will be at `offset + _deltaToOffset(offset)`
	/// after the edits.
	int _deltaToEdit(SourceEdit targetEdit) {
	var delta = 0;
	for (var edit in fileEdit.edits) {
	if (edit.offset < targetEdit.offset) {
	delta += _editDelta(edit);
	}
	}
	return delta;
	}

	/// Return the current delta caused by edits that will be applied before the
	/// given [offset]. In other words, if all of the edits that have so far been
	/// added were to be applied, then the text at the given `offset` before the
	/// applied edits will be at `offset + _deltaToOffset(offset)` after the
	/// edits.
	int _deltaToOffset(int offset) {
	var delta = 0;
	for (var edit in fileEdit.edits) {
	if (edit.offset <= offset) {
	delta += _editDelta(edit);
	}
	}
	return delta;
	}

	/// Return the delta introduced by the given `edit`.
	int _editDelta(SourceEdit edit) => edit.replacement.length - edit.length;
	}

	/// A builder used to build a [LinkedEdit] region within an edit.
	class LinkedEditBuilderImpl implements LinkedEditBuilder {
	final EditBuilderImpl editBuilder;

	final List<LinkedEditSuggestion> suggestions = <LinkedEditSuggestion>[];

	LinkedEditBuilderImpl(this.editBuilder);

	@override
	void addSuggestion(LinkedEditSuggestionKind kind, String value) {
	suggestions.add(LinkedEditSuggestion(value, kind));
	}

	@override
	void addSuggestions(LinkedEditSuggestionKind kind, Iterable<String> values) {
	values.forEach((value) => addSuggestion(kind, value));
	}

	@override
	void write(String string) {
	editBuilder.write(string);
	}

	@override
	void writeln([String? string]) {
	editBuilder.writeln(string);
	}
	}

	/// Workspace that wraps a single [AnalysisSession].
	class _SingleSessionWorkspace extends ChangeWorkspace {
	final AnalysisSession session;

	_SingleSessionWorkspace(this.session);

	@override
	ResourceProvider get resourceProvider => session.resourceProvider;

	@override
	bool? containsFile(String path) {
	var analysisContext = session.analysisContext;
	return analysisContext.contextRoot.isAnalyzed(path);
	}

	@override
	AnalysisSession? getSession(String path) {
	if (containsFile(path) ?? false) {
	return session;
	}
	throw StateError('Not in a context root: $path');
	}
	}