Add utilities for creating SourceChanges

pkg/analysis_server/lib/src/utilities/change_builder_core.dart

Index: pkg/analysis_server/lib/src/utilities/change_builder_core.dart
diff --git a/pkg/analysis_server/lib/src/utilities/change_builder_core.dart b/pkg/analysis_server/lib/src/utilities/change_builder_core.dart
new file mode 100644
index 0000000000000000000000000000000000000000..f0adb54e52a6de87a9b7df61c42adc75788ab6c1
--- /dev/null
+++ b/pkg/analysis_server/lib/src/utilities/change_builder_core.dart
@@ -0,0 +1,249 @@
+// 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.
+
+library analysis_server.src.utilities.change_builder_core;
+
+import 'package:analysis_server/src/protocol.dart';
+import 'package:analysis_server/utilities/change_builder_core.dart';
+import 'package:analyzer/src/generated/source.dart';
+
+/**
+ * A builder used to build a [SourceChange].
+ */
+class ChangeBuilderImpl implements ChangeBuilder {
+  /**
+   * The end-of-line marker used in the file being edited, or `null` if the
+   * default marker should be used.
+   */
+  String eol = null;
+
+  /**
+   * The change that is being built.
+   */
+  final SourceChange _change = new SourceChange('');
+
+  /**
+   * A table mapping group ids to the associated linked edit groups.
+   */
+  final Map<String, LinkedEditGroup> _linkedEditGroups =
+      <String, LinkedEditGroup>{};
+
+  /**
+   * Initialize a newly created change builder.
+   */
+  ChangeBuilderImpl();
+
+  @override
+  SourceChange get sourceChange {
+    _linkedEditGroups.forEach((String name, LinkedEditGroup group) {
+      _change.addLinkedEditGroup(group);
+    });
+    _linkedEditGroups.clear();
+    return _change;
+  }
+
+  @override
+  void addFileEdit(Source source, int fileStamp,
+      void buildFileEdit(FileEditBuilder builder)) {
+    FileEditBuilderImpl builder = createFileEditBuilder(source, fileStamp);
+    try {
+      buildFileEdit(builder);
+    } finally {
+      _change.addFileEdit(builder.fileEdit);
+    }
+  }
+
+  /**
+   * Create and return a [FileEditBuilder] that can be used to build edits to
+   * the given [source].
+   */
+  FileEditBuilderImpl createFileEditBuilder(Source source, int fileStamp) {
+    return new FileEditBuilderImpl(this, source, fileStamp);
+  }
+
+  /**
+   * Return the linked edit group with the given [groupName], creating it if it
+   * did not already exist.
+   */
+  LinkedEditGroup getLinkedEditGroup(String groupName) {
+    LinkedEditGroup group = _linkedEditGroups[groupName];

[Paul Berry, 2015/05/04 16:00:28]

This could be written more compactly as:

return _linkedEditGroups.putIfAbsent(groupName, () => new
LinkedEditGroup.empty());

+    if (group == null) {
+      group = new LinkedEditGroup.empty();
+      _linkedEditGroups[groupName] = group;
+    }
+    return group;
+  }
+}
+
+/**
+ * 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 end-of-line marker used in the file being edited, or `null` if the
+   * default marker should be used.
+   */
+  String _eol = null;
+
+  /**
+   * The buffer in which the content of the edit is being composed.
+   */
+  final StringBuffer _buffer = new 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 =>
+      new SourceEdit(offset, length, _buffer.toString());
+
+  @override
+  void addLinkedEdit(
+      String groupName, void buildLinkedEdit(LinkedEditBuilder builder)) {
+    LinkedEditBuilderImpl builder = createLinkedEditBuilder();
+    int start = offset + _buffer.length;
+    try {
+      buildLinkedEdit(builder);
+    } finally {
+      int end = offset + _buffer.length;
+      int length = end - start;
+      Position position = new Position(fileEditBuilder.fileEdit.file, start);
+      LinkedEditGroup group =
+          fileEditBuilder.changeBuilder.getLinkedEditGroup(groupName);
+      group.addPosition(position, length);
+      for (LinkedEditSuggestion suggestion in builder.suggestions) {
+        group.addSuggestion(suggestion);
+      }
+    }
+  }
+
+  LinkedEditBuilderImpl createLinkedEditBuilder() {
+    return new LinkedEditBuilderImpl(this);
+  }
+
+  @override
+  void write(String string) {
+    _buffer.write(string);
+  }
+
+  @override
+  void writeln([String string]) {
+    _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 [timeStamp] and [timeStamp].
+   */
+  FileEditBuilderImpl(this.changeBuilder, Source source, int timeStamp)
+      : fileEdit = new SourceFileEdit(source.fullName, timeStamp);
+
+  @override
+  void addInsertion(int offset, void buildEdit(EditBuilder builder)) {
+    EditBuilderImpl builder = createEditBuilder(offset, 0);
+    try {
+      buildEdit(builder);
+    } finally {
+      fileEdit.add(builder.sourceEdit);
+    }
+  }
+
+  @override
+  void addLinkedPosition(int offset, int length, String groupName) {
+    LinkedEditGroup group = changeBuilder.getLinkedEditGroup(groupName);
+    Position position = new Position(fileEdit.file, offset);
+    group.addPosition(position, length);
+  }
+
+  @override
+  void addReplacement(
+      int offset, int length, void buildEdit(EditBuilder builder)) {
+    EditBuilderImpl builder = createEditBuilder(offset, length);
+    try {
+      buildEdit(builder);
+    } finally {
+      fileEdit.add(builder.sourceEdit);
+    }
+  }
+
+  EditBuilderImpl createEditBuilder(int offset, int length) {
+    return new EditBuilderImpl(this, offset, 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(new LinkedEditSuggestion(value, kind));
+  }
+
+  @override
+  void addSuggestions(LinkedEditSuggestionKind kind, List<String> values) {
+    values.forEach((value) => addSuggestion(kind, value));
+  }
+
+  @override
+  void write(String string) {
+    editBuilder.write(string);
+  }
+
+  @override
+  void writeln([String string]) {
+    editBuilder.writeln(string);
+  }
+}