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1 // Copyright (c) 2014, 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 /// Instrument your code with counters, gauges, and more. | |
6 library dart.profiler; | |
7 | |
8 import 'dart:convert'; | |
9 | |
10 /// A UserTag can be used to group samples in the Observatory profiler. | |
11 abstract class UserTag { | |
12 /// The maximum number of UserTag instances that can be created by a program. | |
13 static const MAX_USER_TAGS = 64; | |
14 | |
15 factory UserTag(String label) => new _FakeUserTag(label); | |
16 | |
17 /// Label of [this]. | |
18 String get label; | |
19 | |
20 /// Make [this] the current tag for the isolate. Returns the current tag | |
21 /// before setting. | |
22 UserTag makeCurrent(); | |
23 | |
24 /// The default [UserTag] with label 'Default'. | |
25 static UserTag get defaultTag => _FakeUserTag._defaultTag; | |
26 } | |
27 | |
28 // This is a fake implementation of UserTag so that code can compile and run | |
29 // in dart2js. | |
30 class _FakeUserTag implements UserTag { | |
31 static Map _instances = {}; | |
32 | |
33 _FakeUserTag.real(this.label); | |
34 | |
35 factory _FakeUserTag(String label) { | |
36 // Canonicalize by name. | |
37 var existingTag = _instances[label]; | |
38 if (existingTag != null) { | |
39 return existingTag; | |
40 } | |
41 // Throw an exception if we've reached the maximum number of user tags. | |
42 if (_instances.length == UserTag.MAX_USER_TAGS) { | |
43 throw new UnsupportedError( | |
44 'UserTag instance limit (${UserTag.MAX_USER_TAGS}) reached.'); | |
45 } | |
46 // Create a new instance and add it to the instance map. | |
47 var instance = new _FakeUserTag.real(label); | |
48 _instances[label] = instance; | |
49 return instance; | |
50 } | |
51 | |
52 final String label; | |
53 | |
54 UserTag makeCurrent() { | |
55 var old = _currentTag; | |
56 _currentTag = this; | |
57 return old; | |
58 } | |
59 | |
60 static final UserTag _defaultTag = new _FakeUserTag('Default'); | |
61 } | |
62 | |
63 var _currentTag = _FakeUserTag._defaultTag; | |
64 | |
65 /// Returns the current [UserTag] for the isolate. | |
66 UserTag getCurrentTag() { | |
67 return _currentTag; | |
68 } | |
69 | |
70 /// Abstract [Metric] class. Metric names must be unique, are hierarchical, | |
71 /// and use periods as separators. For example, 'a.b.c'. Uniqueness is only | |
72 /// enforced when a Metric is registered. The name of a metric cannot contain | |
73 /// the slash ('/') character. | |
74 abstract class Metric { | |
75 /// [name] of this metric. | |
76 final String name; | |
77 /// [description] of this metric. | |
78 final String description; | |
79 | |
80 Metric(this.name, this.description) { | |
81 if ((name == 'vm') || name.contains('/')) { | |
82 throw new ArgumentError('Invalid Metric name.'); | |
83 } | |
84 | |
85 } | |
86 | |
87 Map _toJSON(); | |
88 } | |
89 | |
90 /// A measured value with a min and max. Initial value is min. Value will | |
91 /// be clamped to the interval [min, max]. | |
92 class Gauge extends Metric { | |
93 final double min; | |
94 final double max; | |
95 | |
96 double _value; | |
97 double get value => _value; | |
98 set value(double v) { | |
99 if (v < min) { | |
100 v = min; | |
101 } else if (v > max) { | |
102 v = max; | |
103 } | |
104 _value = v; | |
105 } | |
106 | |
107 Gauge(String name, String description, this.min, this.max) | |
108 : super(name, description) { | |
109 if (min is! double) { | |
110 throw new ArgumentError('min must be a double'); | |
111 } | |
112 if (max is! double) { | |
113 throw new ArgumentError('max must be a double'); | |
114 } | |
115 if (!(min < max)) { | |
116 throw new ArgumentError('min must be less than max'); | |
117 } | |
118 _value = min; | |
119 } | |
120 | |
121 Map _toJSON() { | |
122 var map = { | |
123 'type': 'Gauge', | |
124 'id': 'metrics/$name', | |
125 'name': name, | |
126 'description': description, | |
127 'value': value, | |
128 'min': min, | |
129 'max': max, | |
130 }; | |
131 return map; | |
132 } | |
133 } | |
134 | |
135 | |
136 /// A changing value. Initial value is 0.0. | |
137 class Counter extends Metric { | |
138 Counter(String name, String description) | |
139 : super(name, description); | |
140 | |
141 double _value = 0.0; | |
142 double get value => _value; | |
143 set value(double v) { | |
144 _value = v; | |
145 } | |
146 | |
147 Map _toJSON() { | |
148 var map = { | |
149 'type': 'Counter', | |
150 'id': 'metrics/$name', | |
151 'name': name, | |
152 'description': description, | |
153 'value': value, | |
154 }; | |
155 return map; | |
156 } | |
157 } | |
158 | |
159 class Metrics { | |
160 static final Map<String, Metric> _metrics = new Map<String, Metric>(); | |
161 | |
162 /// Register [Metric]s to make them visible to Observatory. | |
163 static void register(Metric metric) { | |
164 if (metric is! Metric) { | |
165 throw new ArgumentError('metric must be a Metric'); | |
166 } | |
167 if (_metrics[metric.name] != null) { | |
168 throw new ArgumentError('Registered metrics have unique names'); | |
169 } | |
170 _metrics[metric.name] = metric; | |
171 } | |
172 | |
173 /// Deregister [Metric]s to make them not visible to Observatory. | |
174 static void deregister(Metric metric) { | |
175 if (metric is! Metric) { | |
176 throw new ArgumentError('metric must be a Metric'); | |
177 } | |
178 _metrics.remove(metric.name); | |
179 } | |
180 | |
181 static String _printMetric(String id) { | |
182 var metric = _metrics[id]; | |
183 if (metric == null) { | |
184 return null; | |
185 } | |
186 return JSON.encode(metric._toJSON()); | |
187 } | |
188 | |
189 static String _printMetrics() { | |
190 var metrics = []; | |
191 for (var metric in _metrics.values) { | |
192 metrics.add(metric._toJSON()); | |
193 } | |
194 var map = { | |
195 'type': 'MetricList', | |
196 'metrics': metrics, | |
197 }; | |
198 return JSON.encode(map); | |
199 } | |
200 } | |
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