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pkg/dev_compiler/tool/input_sdk/lib/core/exceptions.dart

-// Copyright (c) 2012, 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.
-
-part of dart.core;
-
-// Exceptions are thrown either by the VM or from Dart code.
-
-/**
- * A marker interface implemented by all core library exceptions.
- *
- * An [Exception] is intended to convey information to the user about a failure,
- * so that the error can be addressed programmatically. It is intended to be
- * caught, and it should contain useful data fields.
- *
- * Creating instances of [Exception] directly with [:new Exception("message"):]
- * is discouraged, and only included as a temporary measure during development,
- * until the actual exceptions used by a library are done.
- */
-abstract class Exception {
-  factory Exception([var message]) => new _Exception(message);
-}
-
-
-/** Default implementation of [Exception] which carries a message. */
-class _Exception implements Exception {
-  final message;
-
-  _Exception([this.message]);
-
-  String toString() {
-    if (message == null) return "Exception";
-    return "Exception: $message";
-  }
-}
-
-
-/**
- * Exception thrown when a string or some other data does not have an expected
- * format and cannot be parsed or processed.
- */
-class FormatException implements Exception {
-  /**
-   * A message describing the format error.
-   */
-  final String message;
-
-  /**
-   * The actual source input which caused the error.
-   *
-   * This is usually a [String], but can be other types too.
-   * If it is a string, parts of it may be included in the [toString] message.
-   *
-   * The source is `null` if omitted or unknown.
-   */
-  final source;
-
-  /**
-   * The offset in [source] where the error was detected.
-   *
-   * A zero-based offset into the source that marks the format error causing
-   * this exception to be created. If `source` is a string, this should be a
-   * string index in the range `0 <= offset <= source.length`.
-   *
-   * If input is a string, the [toString] method may represent this offset as
-   * a line and character position. The offset should be inside the string,
-   * or at the end of the string.
-   *
-   * May be omitted. If present, [source] should also be present if possible.
-   */
-  final int offset;
-
-  /**
-   * Creates a new FormatException with an optional error [message].
-   *
-   * Optionally also supply the actual [source] with the incorrect format,
-   * and the [offset] in the format where a problem was detected.
-   */
-  const FormatException([this.message = "", this.source, this.offset]);
-
-  /**
-   * Returns a description of the format exception.
-   *
-   * The description always contains the [message].
-   *
-   * If [source] is present and is a string, the description will contain
-   * (at least a part of) the source.
-   * If [offset] is also provided, the part of the source included will
-   * contain that offset, and the offset will be marked.
-   *
-   * If the source is a string and it contains a line break before offset,
-   * only the line containing offset will be included, and its line number
-   * will also be part of the description. Line and character offsets are
-   * 1-based.
-   */
-  String toString() {
-    String report = "FormatException";
-    if (message != null && "" != message) {
-      report = "$report: $message";
-    }
-    int offset = this.offset;
-    if (source is! String) {
-      if (offset != null) {
-        report += " (at offset $offset)";
-      }
-      return report;
-    }
-    if (offset != null && (offset < 0 || offset > source.length)) {
-      offset = null;
-    }
-    // Source is string and offset is null or valid.
-    if (offset == null) {
-      String source = this.source;
-      if (source.length > 78) {
-        source = source.substring(0, 75) + "...";
-      }
-      return "$report\n$source";
-    }
-    int lineNum = 1;
-    int lineStart = 0;
-    bool lastWasCR;
-    for (int i = 0; i < offset; i++) {
-      int char = source.codeUnitAt(i);
-      if (char == 0x0a) {
-        if (lineStart != i || !lastWasCR) {
-          lineNum++;
-        }
-        lineStart = i + 1;
-        lastWasCR = false;
-      } else if (char == 0x0d) {
-        lineNum++;
-        lineStart = i + 1;
-        lastWasCR = true;
-      }
-    }
-    if (lineNum > 1) {
-      report += " (at line $lineNum, character ${offset - lineStart + 1})\n";
-    } else {
-      report += " (at character ${offset + 1})\n";
-    }
-    int lineEnd = source.length;
-    for (int i = offset; i < source.length; i++) {
-      int char = source.codeUnitAt(i);
-      if (char == 0x0a || char == 0x0d) {
-        lineEnd = i;
-        break;
-      }
-    }
-    int length = lineEnd - lineStart;
-    int start = lineStart;
-    int end = lineEnd;
-    String prefix = "";
-    String postfix = "";
-    if (length > 78) {
-      // Can't show entire line. Try to anchor at the nearest end, if
-      // one is within reach.
-      int index = offset - lineStart;
-      if (index < 75) {
-        end = start + 75;
-        postfix = "...";
-      } else if (end - offset < 75) {
-        start = end - 75;
-        prefix = "...";
-      } else {
-        // Neither end is near, just pick an area around the offset.
-        start = offset - 36;
-        end = offset + 36;
-        prefix = postfix = "...";
-      }
-    }
-    String slice = source.substring(start, end);
-    int markOffset = offset - start + prefix.length;
-    return "$report$prefix$slice$postfix\n${" " * markOffset}^\n";
-  }
-}
-
-// Exception thrown when doing integer division with a zero divisor.
-class IntegerDivisionByZeroException implements Exception {
-  const IntegerDivisionByZeroException();
-  String toString() => "IntegerDivisionByZeroException";
-}