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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 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. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 part of dart.core; | 5 part of dart.core; |
6 | 6 |
7 // Exceptions are thrown either by the VM or from Dart code. | 7 // Exceptions are thrown either by the VM or from Dart code. |
8 | 8 |
9 /** | 9 /** |
10 * A marker interface implemented by all core library exceptions. | 10 * A marker interface implemented by all core library exceptions. |
(...skipping 26 matching lines...) Expand all Loading... | |
37 | 37 |
38 /** | 38 /** |
39 * Exception thrown when a string or some other data does not have an expected | 39 * Exception thrown when a string or some other data does not have an expected |
40 * format and cannot be parsed or processed. | 40 * format and cannot be parsed or processed. |
41 */ | 41 */ |
42 class FormatException implements Exception { | 42 class FormatException implements Exception { |
43 /** | 43 /** |
44 * A message describing the format error. | 44 * A message describing the format error. |
45 */ | 45 */ |
46 final String message; | 46 final String message; |
47 /** | |
48 * The source that caused the error. | |
nweiz
2014/07/14 19:33:50
The documentation and name doesn't make it clear a
Lasse Reichstein Nielsen
2014/07/15 08:55:59
I'll try to make it more explicit, including the w
| |
49 * | |
50 * This is usually a [String], but can be other types too. If it is a string, | |
51 * parts of it may be included in the [toString] message. | |
52 * | |
53 * May also be `null` if omitted. | |
54 */ | |
55 final source; | |
nweiz
2014/07/14 19:33:49
It would be a lot more useful to consumers of this
Lasse Reichstein Nielsen
2014/07/15 08:55:59
I don't want to mandate a type. It will almost alw
| |
56 /** | |
57 * The position in source where the error was detected. | |
nweiz
2014/07/14 19:33:49
Please be clearer about what you mean by "position
Lasse Reichstein Nielsen
2014/07/15 08:55:59
I like "offset", so I changed it everywhere.
Also
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58 * | |
59 * May be omitted. If present, [source] should also be present. | |
60 */ | |
61 final int position; | |
47 | 62 |
48 /** | 63 /** |
49 * Creates a new FormatException with an optional error [message]. | 64 * Creates a new FormatException with an optional error [message]. |
65 * | |
66 * Optionally also supply the [source] that had the incorrect format, and | |
67 * even the [position] in the format where this was detected. | |
50 */ | 68 */ |
51 const FormatException([this.message = ""]); | 69 const FormatException([this.message = "", this.source, this.position]); |
52 | 70 |
53 String toString() => "FormatException: $message"; | 71 /** |
72 * Returns a description of the format exception. | |
73 * | |
74 * The description always contains the [message]. | |
75 * If [source] was provided, the description will contain (at least a part of) | |
76 * the source. | |
77 * If [position] is also provided, the part of the source included will | |
78 * contain that position, and the position will be marked. | |
79 * | |
80 * If the source contains a line break before position, only the line | |
81 * containing position will be included, and its line number will also be | |
82 * part of the description. Line and character offsets are 1-based. | |
83 */ | |
84 String toString() { | |
85 String report = "FormatException"; | |
86 if (message != null && message.isNotEmpty) { | |
87 report = "$report: $message"; | |
88 } | |
89 int position = this.position; | |
90 if (source is! String) { | |
91 if (position != null) { | |
92 report += " (at position $position)"; | |
93 } | |
94 return report; | |
95 } | |
96 if (position != null && (position < 0 || position > source.length)) { | |
97 position = null; | |
98 } | |
99 // Source is string and position is null or valid. | |
100 if (position == null) { | |
101 String source = this.source; | |
102 if (source.length > 78) { | |
103 source = source.substring(0, 75) + "..."; | |
104 } | |
105 return "$report\n$source"; | |
106 } | |
107 int lineNum = 1; | |
108 int lineStart = 0; | |
109 bool lastWasCR; | |
110 for (int i = 0; i < position; i++) { | |
111 int char = source.codeUnitAt(i); | |
112 if (char == 0x0a) { | |
113 if (lineStart != i || !lastWasCR) { | |
114 lineNum++; | |
115 } | |
116 lineStart = i + 1; | |
117 lastWasCR = false; | |
118 } else if (char == 0x0d) { | |
119 lineNum++; | |
120 lineStart = i + 1; | |
121 lastWasCR = true; | |
122 } | |
123 } | |
124 if (lineNum > 1) { | |
125 report += " (at line $lineNum, character ${position - lineStart + 1})\n"; | |
126 } else { | |
127 report += " (at character ${position + 1})\n"; | |
128 } | |
129 int lineEnd = source.length; | |
130 for (int i = position; i < source.length; i++) { | |
131 int char = source.codeUnitAt(i); | |
132 if (char == 0x0a || char == 0x0d) { | |
133 lineEnd = i; | |
134 break; | |
135 } | |
136 } | |
137 int length = lineEnd - lineStart; | |
138 int start = lineStart; | |
139 int end = lineEnd; | |
140 String prefix = ""; | |
141 String postfix = ""; | |
142 if (length > 78) { | |
143 // Can't show entire line. Try to anchor at the nearest end, if | |
144 // one is within reach. | |
145 int index = position - lineStart; | |
146 if (index < 75) { | |
147 end = start + 75; | |
148 postfix = "..."; | |
149 } else if (end - position < 75) { | |
150 start = end - 75; | |
151 prefix = "..."; | |
152 } else { | |
153 // Neither end is near, just pick an area around the position. | |
154 start = position - 36; | |
155 end = position + 36; | |
156 prefix = postfix = "..."; | |
157 } | |
158 } | |
159 String slice = source.substring(start, end); | |
160 int markOffset = position - start + prefix.length; | |
161 return "$report$prefix$slice$postfix\n${" " * markOffset}^\n"; | |
162 } | |
54 } | 163 } |
55 | 164 |
56 class IntegerDivisionByZeroException implements Exception { | 165 class IntegerDivisionByZeroException implements Exception { |
57 const IntegerDivisionByZeroException(); | 166 const IntegerDivisionByZeroException(); |
58 String toString() => "IntegerDivisionByZeroException"; | 167 String toString() => "IntegerDivisionByZeroException"; |
59 } | 168 } |
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