Add VMMetric and some sample metrics

runtime/vm/metrics.h

Index: runtime/vm/metrics.h
diff --git a/runtime/vm/metrics.h b/runtime/vm/metrics.h
new file mode 100644
index 0000000000000000000000000000000000000000..ab588811600fd4690b739b3a836b193a61d32e28
--- /dev/null
+++ b/runtime/vm/metrics.h
@@ -0,0 +1,141 @@
+// 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.
+
+#ifndef VM_METRICS_H_
+#define VM_METRICS_H_
+
+#include "vm/allocation.h"
+
+namespace dart {
+
+class Isolate;
+class JSONStream;
+
+// Metrics for each isolate.
+#define ISOLATE_METRIC_LIST(V)                                                 \
+  V(MetricHeapOldUsed, HeapOldUsed, "heap.old.used", kByte)                    \
+  V(MetricHeapOldCapacity, HeapOldCapacity, "heap.old.capacity", kByte)        \
+  V(MetricHeapOldExternal, HeapOldExternal, "heap.old.external", kByte)        \
+  V(MetricHeapNewUsed, HeapNewUsed, "heap.new.used", kByte)                    \
+  V(MetricHeapNewCapacity, HeapNewCapacity, "heap.new.capacity", kByte)        \
+  V(MetricHeapNewExternal, HeapNewExternal, "heap.new.external", kByte)        \
+
+#define VM_METRIC_LIST(V)                                                      \
+  V(MetricIsolateCount, IsolateCount, "vm.isolate.count", kCounter)            \
+
+class Metric {
+ public:
+  enum Unit {
+    kCounter,
+    kByte,
+  };
+
+  Metric();
+
+  static void InitOnce();
+
+  // Initialize and register a metric for an isolate.
+  void Init(Isolate* isolate,
+            const char* name,
+            const char* description,
+            Unit unit);
+
+  // Initialize and register a metric for the VM.
+  void Init(const char* name,
+            const char* description,
+            Unit unit);
+
+  virtual ~Metric();
+
+  void PrintJSON(JSONStream* stream);
+
+  int64_t value() const { return value_; }
+  void set_value(int64_t value) { value_ = value; }
+
+  void increment() { value_++; }
+
+  Metric* next() const { return next_; }
+  void set_next(Metric* next) {
+    next_ = next;
+  }
+
+  const char* name() const { return name_; }
+  const char* description() const { return description_; }
+  Unit unit() const { return unit_; }
+
+  // Will be NULL for Metric that is VM-global.
+  Isolate* isolate() const { return isolate_; }
+
+  static Metric* vm_head() { return vm_list_head_; }
+
+ protected:
+  // Override to get a callback when value is serialized to JSON.
+  // Use this for metrics that produce their value on demand.
+  virtual int64_t Value() const { return value(); }
+
+ private:
+  Isolate* isolate_;
+  const char* name_;
+  const char* description_;
+  Unit unit_;
+  int64_t value_;
+  Metric* next_;
+
+  static bool NameExists(Metric* head, const char* name);
+
+  void RegisterWithIsolate();
+  void DeregisterWithIsolate();
+  void RegisterWithVM();
+  void DeregisterWithVM();
+
+  static Metric* vm_list_head_;
+  DISALLOW_COPY_AND_ASSIGN(Metric);
+};
+
+
+class MetricHeapOldUsed : public Metric {
+ protected:
+  virtual int64_t Value() const;
+};
+
+
+class MetricHeapOldCapacity : public Metric {
+ protected:
+  virtual int64_t Value() const;
+};
+
+
+class MetricHeapOldExternal : public Metric {
+ protected:
+  virtual int64_t Value() const;
+};
+
+
+class MetricHeapNewUsed : public Metric {
+ protected:
+  virtual int64_t Value() const;
+};
+
+
+class MetricHeapNewCapacity : public Metric {
+ protected:
+  virtual int64_t Value() const;
+};
+
+
+class MetricHeapNewExternal : public Metric {
+ protected:
+  virtual int64_t Value() const;
+};
+
+
+class MetricIsolateCount : public Metric {
+ protected:
+  virtual int64_t Value() const;
+};
+
+
+}  // namespace dart
+
+#endif  // VM_METRICS_H_