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| 1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. |
| 4 |
| 5 /// Tools to help implement refactoring like transformations to Dart code. |
| 6 /// |
| 7 /// [TextEditTransaction] supports making a series of changes to a text buffer. |
| 8 /// [guessIndent] helps to guess the appropriate indentiation for the new code. |
| 9 library source_maps.refactor; |
| 10 |
| 11 import 'package:source_span/source_span.dart'; |
| 12 |
| 13 import 'printer.dart'; |
| 14 |
| 15 /// Editable text transaction. |
| 16 /// |
| 17 /// Applies a series of edits using original location |
| 18 /// information, and composes them into the edited string. |
| 19 class TextEditTransaction { |
| 20 final SourceFile file; |
| 21 final String original; |
| 22 final _edits = <_TextEdit>[]; |
| 23 |
| 24 /// Creates a new transaction. |
| 25 TextEditTransaction(this.original, this.file); |
| 26 |
| 27 bool get hasEdits => _edits.length > 0; |
| 28 |
| 29 /// Edit the original text, replacing text on the range [begin] and [end] |
| 30 /// with the [replacement]. [replacement] can be either a string or a |
| 31 /// [NestedPrinter]. |
| 32 void edit(int begin, int end, replacement) { |
| 33 _edits.add(new _TextEdit(begin, end, replacement)); |
| 34 } |
| 35 |
| 36 /// Create a source map [SourceLocation] for [offset]. |
| 37 SourceLocation _loc(int offset) => |
| 38 file != null ? file.location(offset) : null; |
| 39 |
| 40 /// Applies all pending [edit]s and returns a [NestedPrinter] containing the |
| 41 /// rewritten string and source map information. [filename] is given to the |
| 42 /// underlying printer to indicate the name of the generated file that will |
| 43 /// contains the source map information. |
| 44 /// |
| 45 /// Throws [UnsupportedError] if the edits were overlapping. If no edits were |
| 46 /// made, the printer simply contains the original string. |
| 47 NestedPrinter commit() { |
| 48 var printer = new NestedPrinter(); |
| 49 if (_edits.length == 0) { |
| 50 return printer..add(original, location: _loc(0), isOriginal: true); |
| 51 } |
| 52 |
| 53 // Sort edits by start location. |
| 54 _edits.sort(); |
| 55 |
| 56 int consumed = 0; |
| 57 for (var edit in _edits) { |
| 58 if (consumed > edit.begin) { |
| 59 var sb = new StringBuffer(); |
| 60 sb..write(file.location(edit.begin).toolString) |
| 61 ..write(': overlapping edits. Insert at offset ') |
| 62 ..write(edit.begin) |
| 63 ..write(' but have consumed ') |
| 64 ..write(consumed) |
| 65 ..write(' input characters. List of edits:'); |
| 66 for (var e in _edits) sb..write('\n ')..write(e); |
| 67 throw new UnsupportedError(sb.toString()); |
| 68 } |
| 69 |
| 70 // Add characters from the original string between this edit and the last |
| 71 // one, if any. |
| 72 var betweenEdits = original.substring(consumed, edit.begin); |
| 73 printer..add(betweenEdits, location: _loc(consumed), isOriginal: true) |
| 74 ..add(edit.replace, location: _loc(edit.begin)); |
| 75 consumed = edit.end; |
| 76 } |
| 77 |
| 78 // Add any text from the end of the original string that was not replaced. |
| 79 printer.add(original.substring(consumed), |
| 80 location: _loc(consumed), isOriginal: true); |
| 81 return printer; |
| 82 } |
| 83 } |
| 84 |
| 85 class _TextEdit implements Comparable<_TextEdit> { |
| 86 final int begin; |
| 87 final int end; |
| 88 |
| 89 /// The replacement used by the edit, can be a string or a [NestedPrinter]. |
| 90 final replace; |
| 91 |
| 92 _TextEdit(this.begin, this.end, this.replace); |
| 93 |
| 94 int get length => end - begin; |
| 95 |
| 96 String toString() => '(Edit @ $begin,$end: "$replace")'; |
| 97 |
| 98 int compareTo(_TextEdit other) { |
| 99 int diff = begin - other.begin; |
| 100 if (diff != 0) return diff; |
| 101 return end - other.end; |
| 102 } |
| 103 } |
| 104 |
| 105 /// Returns all whitespace characters at the start of [charOffset]'s line. |
| 106 String guessIndent(String code, int charOffset) { |
| 107 // Find the beginning of the line |
| 108 int lineStart = 0; |
| 109 for (int i = charOffset - 1; i >= 0; i--) { |
| 110 var c = code.codeUnitAt(i); |
| 111 if (c == _LF || c == _CR) { |
| 112 lineStart = i + 1; |
| 113 break; |
| 114 } |
| 115 } |
| 116 |
| 117 // Grab all the whitespace |
| 118 int whitespaceEnd = code.length; |
| 119 for (int i = lineStart; i < code.length; i++) { |
| 120 var c = code.codeUnitAt(i); |
| 121 if (c != _SPACE && c != _TAB) { |
| 122 whitespaceEnd = i; |
| 123 break; |
| 124 } |
| 125 } |
| 126 |
| 127 return code.substring(lineStart, whitespaceEnd); |
| 128 } |
| 129 |
| 130 const int _CR = 13; |
| 131 const int _LF = 10; |
| 132 const int _TAB = 9; |
| 133 const int _SPACE = 32; |
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