| // Copyright (c) 2013, 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. |
| |
| /// Tools to help implement refactoring like transformations to Dart code. |
| /// |
| /// [TextEditTransaction] supports making a series of changes to a text buffer. |
| /// [guessIndent] helps to guess the appropriate indentiation for the new code. |
| library source_maps.refactor; |
| |
| import 'span.dart'; |
| import 'printer.dart'; |
| |
| /// Editable text transaction. |
| /// |
| /// Applies a series of edits using original location |
| /// information, and composes them into the edited string. |
| class TextEditTransaction { |
| final SourceFile file; |
| final String original; |
| final _edits = <_TextEdit>[]; |
| |
| TextEditTransaction(this.original, this.file); |
| |
| bool get hasEdits => _edits.length > 0; |
| |
| /// Edit the original text, replacing text on the range [begin] and [end] |
| /// with the [replacement]. [replacement] can be either a string or a |
| /// [NestedPrinter]. |
| void edit(int begin, int end, replacement) { |
| _edits.add(new _TextEdit(begin, end, replacement)); |
| } |
| |
| /// Create a source map [Location] for [offset]. |
| Location _loc(int offset) => |
| file != null ? file.location(offset) : null; |
| |
| /// Applies all pending [edit]s and returns a [NestedPrinter] containing the |
| /// rewritten string and source map information. [filename] is given to the |
| /// underlying printer to indicate the name of the generated file that will |
| /// contains the source map information. |
| /// |
| /// Throws [UnsupportedError] if the edits were overlapping. If no edits were |
| /// made, the printer simply contains the original string. |
| NestedPrinter commit() { |
| var printer = new NestedPrinter(); |
| if (_edits.length == 0) { |
| return printer..add(original, location: _loc(0), isOriginal: true); |
| } |
| |
| // Sort edits by start location. |
| _edits.sort(); |
| |
| int consumed = 0; |
| for (var edit in _edits) { |
| if (consumed > edit.begin) { |
| var sb = new StringBuffer(); |
| sb..write(file.location(edit.begin).formatString) |
| ..write(': overlapping edits. Insert at offset ') |
| ..write(edit.begin) |
| ..write(' but have consumed ') |
| ..write(consumed) |
| ..write(' input characters. List of edits:'); |
| for (var e in _edits) sb..write('\n ')..write(e); |
| throw new UnsupportedError(sb.toString()); |
| } |
| |
| // Add characters from the original string between this edit and the last |
| // one, if any. |
| var betweenEdits = original.substring(consumed, edit.begin); |
| printer..add(betweenEdits, location: _loc(consumed), isOriginal: true) |
| ..add(edit.replace, location: _loc(edit.begin)); |
| consumed = edit.end; |
| } |
| |
| // Add any text from the end of the original string that was not replaced. |
| printer.add(original.substring(consumed), |
| location: _loc(consumed), isOriginal: true); |
| return printer; |
| } |
| } |
| |
| class _TextEdit implements Comparable<_TextEdit> { |
| final int begin; |
| final int end; |
| |
| /// The replacement used by the edit, can be a string or a [NestedPrinter]. |
| final replace; |
| |
| _TextEdit(this.begin, this.end, this.replace); |
| |
| int get length => end - begin; |
| |
| String toString() => '(Edit @ $begin,$end: "$replace")'; |
| |
| int compareTo(_TextEdit other) { |
| int diff = begin - other.begin; |
| if (diff != 0) return diff; |
| return end - other.end; |
| } |
| } |
| |
| /// Returns all whitespace characters at the start of [charOffset]'s line. |
| String guessIndent(String code, int charOffset) { |
| // Find the beginning of the line |
| int lineStart = 0; |
| for (int i = charOffset - 1; i >= 0; i--) { |
| var c = code.codeUnitAt(i); |
| if (c == _LF || c == _CR) { |
| lineStart = i + 1; |
| break; |
| } |
| } |
| |
| // Grab all the whitespace |
| int whitespaceEnd = code.length; |
| for (int i = lineStart; i < code.length; i++) { |
| var c = code.codeUnitAt(i); |
| if (c != _SPACE && c != _TAB) { |
| whitespaceEnd = i; |
| break; |
| } |
| } |
| |
| return code.substring(lineStart, whitespaceEnd); |
| } |
| |
| const int _CR = 13; |
| const int _LF = 10; |
| const int _TAB = 9; |
| const int _SPACE = 32; |