pkg/analyzer/lib/exception/exception.dart

// Copyright (c) 2014, 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.

/**
 * An exception that occurred during the analysis of one or more sources.
 */
class AnalysisException implements Exception {
  /**
   * The message that explains why the exception occurred.
   */
  final String message;

  /**
   * The exception that caused this exception, or `null` if this exception was
   * not caused by another exception.
   */
  final CaughtException cause;

  /**
   * Initialize a newly created exception to have the given [message] and
   * [cause].
   */
  AnalysisException([this.message = 'Exception', this.cause]);

  String toString() {
    StringBuffer buffer = new StringBuffer();
    buffer.write('$runtimeType: ');
    buffer.writeln(message);
    if (cause != null) {
      buffer.write('Caused by ');
      cause._writeOn(buffer);
    }
    return buffer.toString();
  }
}

/**
 * An exception that was caught and has an associated stack trace.
 */
class CaughtException implements Exception {
  /**
   * The exception that was caught.
   */
  final Object exception;

  /**
   * The message describing where/how/why this was caught.
   */
  final String message;

  /**
   * The stack trace associated with the exception.
   */
  StackTrace stackTrace;

  /**
   * Initialize a newly created caught exception to have the given [exception]
   * and [stackTrace].
   */
  CaughtException(exception, stackTrace)
      : this.withMessage(null, exception, stackTrace);

  /**
   * Initialize a newly created caught exception to have the given [exception],
   * [stackTrace], and [message].
   */
  CaughtException.withMessage(this.message, this.exception, stackTrace)
      : this.stackTrace = stackTrace ?? StackTrace.current;

  /**
   * Create a [CaughtException] to wrap a prior one, adding a [message].
   */
  CaughtException.wrapInMessage(String message, CaughtException exception)
      : this.withMessage(message, exception, null);

  @override
  String toString() {
    StringBuffer buffer = new StringBuffer();
    _writeOn(buffer);
    return buffer.toString();
  }

  /**
   * Write a textual representation of the caught exception and its associated
   * stack trace.
   */
  void _writeOn(StringBuffer buffer) {
    if (message != null) {
      buffer.writeln(message);
    }
    if (exception is AnalysisException) {
      AnalysisException analysisException = exception;
      buffer.writeln(analysisException.message);
      if (stackTrace != null) {
        buffer.writeln(stackTrace.toString());
      }
      CaughtException cause = analysisException.cause;
      if (cause != null) {
        buffer.write('Caused by ');
        cause._writeOn(buffer);
      }
    } else {
      buffer.writeln(exception.toString());
      if (stackTrace != null) {
        buffer.writeln(stackTrace.toString());
      }
    }
  }
}