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pkg/dev_compiler/tool/input_sdk/lib/developer/profiler.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.
-
-part of dart.developer;
-
-/// A UserTag can be used to group samples in the Observatory profiler.
-abstract class UserTag {
-  /// The maximum number of UserTag instances that can be created by a program.
-  static const MAX_USER_TAGS = 64;
-
-  factory UserTag(String label) => new _FakeUserTag(label);
-
-  /// Label of [this].
-  String get label;
-
-  /// Make [this] the current tag for the isolate. Returns the current tag
-  /// before setting.
-  UserTag makeCurrent();
-
-  /// The default [UserTag] with label 'Default'.
-  static UserTag get defaultTag => _FakeUserTag._defaultTag;
-}
-
-// This is a fake implementation of UserTag so that code can compile and run
-// in dart2js.
-class _FakeUserTag implements UserTag {
-  static Map _instances = {};
-
-  _FakeUserTag.real(this.label);
-
-  factory _FakeUserTag(String label) {
-    // Canonicalize by name.
-    var existingTag = _instances[label];
-    if (existingTag != null) {
-      return existingTag;
-    }
-    // Throw an exception if we've reached the maximum number of user tags.
-    if (_instances.length == UserTag.MAX_USER_TAGS) {
-      throw new UnsupportedError(
-          'UserTag instance limit (${UserTag.MAX_USER_TAGS}) reached.');
-    }
-    // Create a new instance and add it to the instance map.
-    var instance = new _FakeUserTag.real(label);
-    _instances[label] = instance;
-    return instance;
-  }
-
-  final String label;
-
-  UserTag makeCurrent() {
-    var old = _currentTag;
-    _currentTag = this;
-    return old;
-  }
-
-  static final UserTag _defaultTag = new _FakeUserTag('Default');
-}
-
-var _currentTag = _FakeUserTag._defaultTag;
-
-/// Returns the current [UserTag] for the isolate.
-UserTag getCurrentTag() {
-  return _currentTag;
-}
-
-/// Abstract [Metric] class. Metric names must be unique, are hierarchical,
-/// and use periods as separators. For example, 'a.b.c'. Uniqueness is only
-/// enforced when a Metric is registered. The name of a metric cannot contain
-/// the slash ('/') character.
-abstract class Metric {
-  /// [name] of this metric.
-  final String name;
-  /// [description] of this metric.
-  final String description;
-
-  Metric(this.name, this.description) {
-    if ((name == 'vm') || name.contains('/')) {
-      throw new ArgumentError('Invalid Metric name.');
-    }
-
-  }
-
-  Map _toJSON();
-}
-
-/// A measured value with a min and max. Initial value is min. Value will
-/// be clamped to the interval [min, max].
-class Gauge extends Metric {
-  final double min;
-  final double max;
-
-  double _value;
-  double get value => _value;
-  set value(double v) {
-    if (v < min) {
-      v = min;
-    } else if (v > max) {
-      v = max;
-    }
-    _value = v;
-  }
-
-  Gauge(String name, String description, this.min, this.max)
-      : super(name, description) {
-    if (min is! double) {
-      throw new ArgumentError('min must be a double');
-    }
-    if (max is! double) {
-      throw new ArgumentError('max must be a double');
-    }
-    if (!(min < max)) {
-      throw new ArgumentError('min must be less than max');
-    }
-    _value = min;
-  }
-
-  Map _toJSON() {
-    var map = {
-      'type': 'Gauge',
-      'id': 'metrics/$name',
-      'name': name,
-      'description': description,
-      'value': value,
-      'min': min,
-      'max': max,
-    };
-    return map;
-  }
-}
-
-
-/// A changing value. Initial value is 0.0.
-class Counter extends Metric {
-  Counter(String name, String description)
-      : super(name, description);
-
-  double _value = 0.0;
-  double get value => _value;
-  set value(double v) {
-    _value = v;
-  }
-
-  Map _toJSON() {
-    var map = {
-      'type': 'Counter',
-      'id': 'metrics/$name',
-      'name': name,
-      'description': description,
-      'value': value,
-    };
-    return map;
-  }
-}
-
-class Metrics {
-  static final Map<String, Metric> _metrics = new Map<String, Metric>();
-
-  /// Register [Metric]s to make them visible to Observatory.
-  static void register(Metric metric) {
-    if (metric is! Metric) {
-      throw new ArgumentError('metric must be a Metric');
-    }
-    if (_metrics[metric.name] != null) {
-      throw new ArgumentError('Registered metrics have unique names');
-    }
-    _metrics[metric.name] = metric;
-  }
-
-  /// Deregister [Metric]s to make them not visible to Observatory.
-  static void deregister(Metric metric) {
-    if (metric is! Metric) {
-      throw new ArgumentError('metric must be a Metric');
-    }
-    _metrics.remove(metric.name);
-  }
-
-  static String _printMetric(String id) {
-    var metric = _metrics[id];
-    if (metric == null) {
-      return null;
-    }
-    return JSON.encode(metric._toJSON());
-  }
-
-  static String _printMetrics() {
-    var metrics = [];
-    for (var metric in _metrics.values) {
-      metrics.add(metric._toJSON());
-    }
-    var map = {
-      'type': 'MetricList',
-      'metrics': metrics,
-    };
-    return JSON.encode(map);
-  }
-}