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1 // for details. All rights reserved. Use of this source code is governed by a | |
Jennifer Messerly
2013/08/09 05:44:03
first line of copyright disappeared?
Siggi Cherem (dart-lang)
2013/08/09 22:09:09
oops, fixed.
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2 // BSD-style license that can be found in the LICENSE file. | |
3 | |
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 */ | |
10 library codegen.refactor; | |
11 | |
12 import 'printer.dart'; | |
13 import 'package:source_maps/span.dart'; | |
14 | |
15 const $CR = 13; | |
16 const $LF = 10; | |
17 const $TAB = 9; | |
18 const $SPACE = 32; | |
19 | |
20 /** | |
21 * Editable text transaction. Applies a series of edits using original location | |
22 * information, and composes them into the edited string. | |
23 */ | |
24 class TextEditTransaction { | |
25 final SourceFile file; | |
26 final String original; | |
27 final _edits = <_TextEdit>[]; | |
28 | |
29 TextEditTransaction(this.original, this.file); | |
30 | |
31 bool get hasEdits => _edits.length > 0; | |
32 | |
33 /** | |
34 * Edit the original text, replacing text on the range [begin] and [end] | |
35 * with the [replacement]. [replacement] can be either a string or a | |
36 * [CodePrinter]. | |
37 */ | |
38 void edit(int begin, int end, replacement) { | |
39 _edits.add(new _TextEdit(begin, end, replacement)); | |
40 } | |
41 | |
42 /** Create a source map [Location] for [offset]. */ | |
43 Location _loc(int offset) => | |
44 file != null ? file.location(offset) : null; | |
45 | |
46 /** | |
47 * Applies all pending [edit]s and returns the rewritten string. | |
48 * If no edits were made, returns the [original] string. | |
49 * Throws [UnsupportedError] if the edits were overlapping. | |
50 */ | |
51 CodePrinter commit() { | |
52 var printer = new CodePrinter(0); | |
53 if (_edits.length == 0) { | |
54 printer.add(original, location: _loc(0), isOriginal: true); | |
55 return printer; | |
56 } | |
57 | |
58 // Sort edits by start location. | |
59 _edits.sort(); | |
60 | |
61 int consumed = 0; | |
62 for (var edit in _edits) { | |
63 if (consumed > edit.begin) { | |
64 var sb = new StringBuffer(); | |
65 sb..write(file.location(edit.begin).formatString) | |
66 ..write(': overlapping edits. Insert at offset ') | |
67 ..write(edit.begin) | |
68 ..write(' but have consumed ') | |
69 ..write(consumed) | |
70 ..write(' input characters. List of edits:'); | |
71 for (var e in _edits) sb..write('\n ')..write(e); | |
72 throw new UnsupportedError(sb.toString()); | |
73 } | |
74 | |
75 // Add characters from the original string between this edit and the last | |
76 // one, if any. | |
77 var betweenEdits = original.substring(consumed, edit.begin); | |
78 printer..add(betweenEdits, location: _loc(consumed), isOriginal: true) | |
79 ..add(edit.replace, location: _loc(edit.begin)); | |
80 consumed = edit.end; | |
81 } | |
82 | |
83 // Add any text from the end of the original string that was not replaced. | |
84 printer.add(original.substring(consumed), | |
85 location: _loc(consumed), isOriginal: true); | |
86 return printer; | |
87 } | |
88 } | |
89 | |
90 class _TextEdit implements Comparable<_TextEdit> { | |
91 final int begin; | |
92 final int end; | |
93 | |
94 /** The replacement used by the edit, can be a string or a [CodePrinter]. */ | |
95 final replace; | |
96 | |
97 _TextEdit(this.begin, this.end, this.replace); | |
98 | |
99 int get length => end - begin; | |
100 | |
101 String toString() => '(Edit @ $begin,$end: "$replace")'; | |
102 | |
103 int compareTo(_TextEdit other) { | |
104 int diff = begin - other.begin; | |
105 if (diff != 0) return diff; | |
106 return end - other.end; | |
107 } | |
108 } | |
109 | |
110 /** | |
111 * Finds and returns all whitespace characters at the start of the current line. | |
112 */ | |
113 String guessIndent(String code, int charOffset) { | |
114 // Find the beginning of the line | |
115 int lineStart = 0; | |
116 for (int i = charOffset - 1; i >= 0; i--) { | |
117 var c = code.codeUnitAt(i); | |
118 if (c == $LF || c == $CR) { | |
119 lineStart = i + 1; | |
120 break; | |
121 } | |
122 } | |
123 | |
124 // Grab all the whitespace | |
125 int whitespaceEnd = code.length; | |
126 for (int i = lineStart; i < code.length; i++) { | |
127 var c = code.codeUnitAt(i); | |
128 if (c != $SPACE && c != $TAB) { | |
129 whitespaceEnd = i; | |
130 break; | |
131 } | |
132 } | |
133 | |
134 return code.substring(lineStart, whitespaceEnd); | |
135 } | |
136 | |
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