| OLD | NEW |
| (Empty) |
| 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 | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 part of dart.core; | |
| 6 | |
| 7 // Exceptions are thrown either by the VM or from Dart code. | |
| 8 | |
| 9 /** | |
| 10 * A marker interface implemented by all core library exceptions. | |
| 11 * | |
| 12 * An [Exception] is intended to convey information to the user about a failure, | |
| 13 * so that the error can be addressed programmatically. It is intended to be | |
| 14 * caught, and it should contain useful data fields. | |
| 15 * | |
| 16 * Creating instances of [Exception] directly with [:new Exception("message"):] | |
| 17 * is discouraged, and only included as a temporary measure during development, | |
| 18 * until the actual exceptions used by a library are done. | |
| 19 */ | |
| 20 abstract class Exception { | |
| 21 factory Exception([var message]) => new _ExceptionImplementation(message); | |
| 22 } | |
| 23 | |
| 24 | |
| 25 /** Default implementation of [Exception] which carries a message. */ | |
| 26 class _ExceptionImplementation implements Exception { | |
| 27 final message; | |
| 28 | |
| 29 _ExceptionImplementation([this.message]); | |
| 30 | |
| 31 String toString() { | |
| 32 if (message == null) return "Exception"; | |
| 33 return "Exception: $message"; | |
| 34 } | |
| 35 } | |
| 36 | |
| 37 | |
| 38 /** | |
| 39 * Exception thrown when a string or some other data does not have an expected | |
| 40 * format and cannot be parsed or processed. | |
| 41 */ | |
| 42 class FormatException implements Exception { | |
| 43 /** | |
| 44 * A message describing the format error. | |
| 45 */ | |
| 46 final String message; | |
| 47 | |
| 48 /** | |
| 49 * The actual source input that caused the error. | |
| 50 * | |
| 51 * This is usually a [String], but can be other types too. | |
| 52 * If it is a string, parts of it may be included in the [toString] message. | |
| 53 * | |
| 54 * The source is `null` if omitted or unknown. | |
| 55 */ | |
| 56 final source; | |
| 57 | |
| 58 /** | |
| 59 * The offset in [source] where the error was detected. | |
| 60 * | |
| 61 * A zero-based offset into the source that marks the format error causing | |
| 62 * this exception to be created. If `source` is a string, this should be a | |
| 63 * string index in the range `0 <= offset <= source.length`. | |
| 64 * | |
| 65 * If input is a string, the [toString] method may represent this offset as | |
| 66 * a line and character position. The offset should be inside the string, | |
| 67 * or at the end of the string. | |
| 68 * | |
| 69 * May be omitted. If present, [source] should also be present if possible. | |
| 70 */ | |
| 71 final int offset; | |
| 72 | |
| 73 /** | |
| 74 * Creates a new FormatException with an optional error [message]. | |
| 75 * | |
| 76 * Optionally also supply the actual [source] that had the incorrect format, | |
| 77 * and an [offset] in the format where a problem was detected. | |
| 78 */ | |
| 79 const FormatException([this.message = "", this.source, this.offset = -1]); | |
| 80 | |
| 81 /** | |
| 82 * Returns a description of the format exception. | |
| 83 * | |
| 84 * The description always contains the [message]. | |
| 85 * | |
| 86 * If [source] is present and is a string, the description will contain | |
| 87 * (at least a part of) the source. | |
| 88 * If [offset] is also provided, the part of the source included will | |
| 89 * contain that offset, and the offset will be marked. | |
| 90 * | |
| 91 * If the source is a string and it contains a line break before offset, | |
| 92 * only the line containing offset will be included, and its line number | |
| 93 * will also be part of the description. Line and character offsets are | |
| 94 * 1-based. | |
| 95 */ | |
| 96 String toString() { | |
| 97 String report = "FormatException"; | |
| 98 if (message != null && "" != message) { | |
| 99 report = "$report: $message"; | |
| 100 } | |
| 101 int offset = this.offset; | |
| 102 if (source is! String) { | |
| 103 if (offset != -1) { | |
| 104 report += " (at offset $offset)"; | |
| 105 } | |
| 106 return report; | |
| 107 } | |
| 108 if (offset != -1 && (offset < 0 || offset > source.length)) { | |
| 109 offset = -1; | |
| 110 } | |
| 111 // Source is string and offset is null or valid. | |
| 112 if (offset == -1) { | |
| 113 String source = this.source; | |
| 114 if (source.length > 78) { | |
| 115 source = source.substring(0, 75) + "..."; | |
| 116 } | |
| 117 return "$report\n$source"; | |
| 118 } | |
| 119 int lineNum = 1; | |
| 120 int lineStart = 0; | |
| 121 bool lastWasCR; | |
| 122 for (int i = 0; i < offset; i++) { | |
| 123 int char = source.codeUnitAt(i); | |
| 124 if (char == 0x0a) { | |
| 125 if (lineStart != i || !lastWasCR) { | |
| 126 lineNum++; | |
| 127 } | |
| 128 lineStart = i + 1; | |
| 129 lastWasCR = false; | |
| 130 } else if (char == 0x0d) { | |
| 131 lineNum++; | |
| 132 lineStart = i + 1; | |
| 133 lastWasCR = true; | |
| 134 } | |
| 135 } | |
| 136 if (lineNum > 1) { | |
| 137 report += " (at line $lineNum, character ${offset - lineStart + 1})\n"; | |
| 138 } else { | |
| 139 report += " (at character ${offset + 1})\n"; | |
| 140 } | |
| 141 int lineEnd = source.length; | |
| 142 for (int i = offset; i < source.length; i++) { | |
| 143 int char = source.codeUnitAt(i); | |
| 144 if (char == 0x0a || char == 0x0d) { | |
| 145 lineEnd = i; | |
| 146 break; | |
| 147 } | |
| 148 } | |
| 149 int length = lineEnd - lineStart; | |
| 150 int start = lineStart; | |
| 151 int end = lineEnd; | |
| 152 String prefix = ""; | |
| 153 String postfix = ""; | |
| 154 if (length > 78) { | |
| 155 // Can't show entire line. Try to anchor at the nearest end, if | |
| 156 // one is within reach. | |
| 157 int index = offset - lineStart; | |
| 158 if (index < 75) { | |
| 159 end = start + 75; | |
| 160 postfix = "..."; | |
| 161 } else if (end - offset < 75) { | |
| 162 start = end - 75; | |
| 163 prefix = "..."; | |
| 164 } else { | |
| 165 // Neither end is near, just pick an area around the offset. | |
| 166 start = offset - 36; | |
| 167 end = offset + 36; | |
| 168 prefix = postfix = "..."; | |
| 169 } | |
| 170 } | |
| 171 String slice = source.substring(start, end); | |
| 172 int markOffset = offset - start + prefix.length; | |
| 173 return "$report$prefix$slice$postfix\n${" " * markOffset}^\n"; | |
| 174 } | |
| 175 } | |
| 176 | |
| 177 class IntegerDivisionByZeroException implements Exception { | |
| 178 const IntegerDivisionByZeroException(); | |
| 179 String toString() => "IntegerDivisionByZeroException"; | |
| 180 } | |
| OLD | NEW |