add logging support for exceptions

pkg/logging/lib/logging.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.
 
 /**
  * Provides APIs for debugging and error logging. This library introduces
  * abstractions similar to those used in other languages, such as the Closure JS
  * Logger and java.util.logging.Logger.
  *
  * ## Installing ##
@@ skipping 135 matching lines @@
   /** Whether a message for [value]'s level is loggable in this logger. */
   bool isLoggable(Level value) => (value >= level);
 
   /**
    * Adds a log record for a [message] at a particular [logLevel] if
    * `isLoggable(logLevel)` is true. Use this method to create log entries for
    * user-defined levels. To record a message at a predefined level (e.g.
    * [Level.INFO], [Level.WARNING], etc) you can use their specialized methods
    * instead (e.g. [info], [warning], etc).
    */
-  // TODO(sigmund): add support for logging exceptions.
-  void log(Level logLevel, String message) {
+  void log(Level logLevel, String message, [exception]) {
     if (isLoggable(logLevel)) {
-      var record = new LogRecord(logLevel, message, fullName);
+      var record = new LogRecord(logLevel, message, fullName, exception);
       if (hierarchicalLoggingEnabled) {
         var target = this;
         while (target != null) {
           target._publish(record);
           target = target.parent;
         }
       } else {
         root._publish(record);
       }
     }
   }
 
   /** Log message at level [Level.FINEST]. */
-  void finest(String message) => log(Level.FINEST, message);
+  void finest(String message, [exception]) =>
+      log(Level.FINEST, message, exception);
 
   /** Log message at level [Level.FINER]. */
-  void finer(String message) => log(Level.FINER, message);
+  void finer(String message, [exception]) =>
+      log(Level.FINER, message, exception);
 
   /** Log message at level [Level.FINE]. */
-  void fine(String message) => log(Level.FINE, message);
+  void fine(String message, [exception]) =>
+      log(Level.FINE, message, exception);
 
   /** Log message at level [Level.CONFIG]. */
-  void config(String message) => log(Level.CONFIG, message);
+  void config(String message, [exception]) =>
+      log(Level.CONFIG, message, exception);
 
   /** Log message at level [Level.INFO]. */
-  void info(String message) => log(Level.INFO, message);
+  void info(String message, [exception]) =>
+      log(Level.INFO, message, exception);
 
   /** Log message at level [Level.WARNING]. */
-  void warning(String message) => log(Level.WARNING, message);
+  void warning(String message, [exception]) =>
+      log(Level.WARNING, message, exception);
 
   /** Log message at level [Level.SEVERE]. */
-  void severe(String message) => log(Level.SEVERE, message);
+  void severe(String message, [exception]) =>
+      log(Level.SEVERE, message, exception);
 
   /** Log message at level [Level.SHOUT]. */
-  void shout(String message) => log(Level.SHOUT, message);
+  void shout(String message, [exception]) =>
+      log(Level.SHOUT, message, exception);
 
   Stream<LogRecord> _getStream() {
     if (hierarchicalLoggingEnabled || parent == null) {
       if (_controller == null) {
         _controller = new StreamController<LogRecord>(sync: true);
         _stream = _controller.stream.asBroadcastStream();
       }
       return _stream;
     } else {
       return root._getStream();
@@ skipping 96 matching lines @@
 
   /** Time when this record was created. */
   final DateTime time;
 
   /** Unique sequence number greater than all log records created before it. */
   final int sequenceNumber;
 
   static int _nextNumber = 0;
 
   /** Associated exception (if any) when recording errors messages. */
-  Exception exception;
+  var exception;
 
-  /** Associated exception message (if any) when recording errors messages. */
-  String exceptionText;
-
-  LogRecord(
-      this.level, this.message, this.loggerName,
-      [time, this.exception, this.exceptionText]) :
-    this.time = (time == null) ? new DateTime.now() : time,
-    this.sequenceNumber = LogRecord._nextNumber++;
+  LogRecord(this.level, this.message, this.loggerName, [this.exception])
+      : time = new DateTime.now(),
+        sequenceNumber = LogRecord._nextNumber++;
 }