Add VMMetric and some sample metrics

runtime/vm/metrics.cc

Index: runtime/vm/metrics.cc
diff --git a/runtime/vm/metrics.cc b/runtime/vm/metrics.cc
new file mode 100644
index 0000000000000000000000000000000000000000..41a72ad1ff5614322b10a89c36d594be8698ead0
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+++ b/runtime/vm/metrics.cc
@@ -0,0 +1,242 @@
+// 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.
+
+#include "vm/metrics.h"
+
+#include "vm/isolate.h"
+#include "vm/json_stream.h"
+#include "vm/native_entry.h"
+#include "vm/runtime_entry.h"
+#include "vm/object.h"
+
+namespace dart {
+
+Metric* Metric::vm_list_head_ = NULL;
+
+Metric::Metric()
+    : isolate_(NULL),
+      name_(NULL),
+      description_(NULL),
+      unit_(kCounter),
+      value_(0),
+      next_(NULL) {
+}
+
+
+void Metric::Init(Isolate* isolate,
+                  const char* name,
+                  const char* description,
+                  Unit unit) {
+  // Only called once.
+  ASSERT(next_ == NULL);
+  ASSERT(name != NULL);
+  isolate_ = isolate;
+  name_ = name;
+  description_ = description;
+  unit_ = unit;
+  RegisterWithIsolate();
+}
+
+
+void Metric::Init(const char* name, const char* description, Unit unit) {
+  // Only called once.
+  ASSERT(next_ == NULL);
+  ASSERT(name != NULL);
+  name_ = name;
+  description_ = description;
+  unit_ = unit;
+  RegisterWithVM();
+}
+
+
+Metric::~Metric() {
+  if (isolate_ == NULL) {
+    DeregisterWithVM();
+  } else {
+    DeregisterWithIsolate();
+  }
+}
+
+
+static const char* UnitString(intptr_t unit) {
+  switch (unit) {
+    case Metric::kCounter: return "counter";
+    case Metric::kByte: return "byte";
+    default:
+      UNREACHABLE();
+  }
+  UNREACHABLE();
+  return NULL;
+}
+
+
+void Metric::PrintJSON(JSONStream* stream) {
+  JSONObject obj(stream);
+  obj.AddProperty("type", "Counter");
+  obj.AddProperty("name", name_);
+  obj.AddProperty("description", description_);
+  obj.AddProperty("unit", UnitString(unit()));
+  obj.AddPropertyF("id", "metrics/vm/%s", name_);
+  // TODO(johnmccutchan): Overflow?
+  double value_as_double = static_cast<double>(Value());
+  obj.AddProperty("value", value_as_double);
+}
+
+
+bool Metric::NameExists(Metric* head, const char* name) {
+  ASSERT(name != NULL);
+  while (head != NULL) {
+    const char* metric_name = head->name();
+    ASSERT(metric_name != NULL);
+    if (strcmp(metric_name, name) == 0) {
+      return true;
+    }
+    head = head->next();
+  }
+  return false;
+}
+
+
+
+void Metric::RegisterWithIsolate() {
+  ASSERT(isolate_ != NULL);
+  ASSERT(next_ == NULL);
+  // No duplicate names allowed.
+  ASSERT(!NameExists(isolate_->metrics_list_head(), name()));
+  Metric* head = isolate_->metrics_list_head();
+  if (head != NULL) {
+    set_next(head);
+  }
+  isolate_->set_metrics_list_head(this);
+}
+
+
+void Metric::DeregisterWithIsolate() {
+  Metric* head = isolate_->metrics_list_head();
+  ASSERT(head != NULL);
+  // Handle head of list case.
+  if (head == this) {
+    isolate_->set_metrics_list_head(next());
+    set_next(NULL);
+    return;
+  }
+  Metric* previous = NULL;
+  while (true) {
+    previous = head;
+    ASSERT(previous != NULL);
+    head = head->next();
+    if (head == NULL) {
+      break;
+    }
+    if (head == this) {
+      // Remove this from list.
+      previous->set_next(head->next());
+      set_next(NULL);
+      return;
+    }
+    ASSERT(head != NULL);
+  }
+  UNREACHABLE();
+}
+
+
+void Metric::RegisterWithVM() {
+  ASSERT(isolate_ == NULL);
+  ASSERT(next_ == NULL);
+  // No duplicate names allowed.
+  ASSERT(!NameExists(vm_list_head_, name()));
+  Metric* head = vm_list_head_;
+  if (head != NULL) {
+    set_next(head);
+  }
+  vm_list_head_ = this;
+}
+
+
+void Metric::DeregisterWithVM() {
+  ASSERT(isolate_ == NULL);
+  Metric* head = vm_list_head_;
+  if (head == NULL) {
+    return;
+  }
+  // Handle head of list case.
+  if (head == this) {
+    vm_list_head_ = next();
+    set_next(NULL);
+    return;
+  }
+  Metric* previous = NULL;
+  while (true) {
+    previous = head;
+    ASSERT(previous != NULL);
+    head = head->next();
+    if (head == NULL) {
+      break;
+    }
+    if (head == this) {
+      // Remove this from list.
+      previous->set_next(head->next());
+      set_next(NULL);
+      return;
+    }
+    ASSERT(head != NULL);
+  }
+  UNREACHABLE();
+}
+
+
+int64_t MetricHeapOldUsed::Value() const {
+  ASSERT(isolate() == Isolate::Current());
+  return isolate()->heap()->UsedInWords(Heap::kOld) * kWordSize;
+}
+
+
+int64_t MetricHeapOldCapacity::Value() const {
+  ASSERT(isolate() == Isolate::Current());
+  return isolate()->heap()->CapacityInWords(Heap::kOld) * kWordSize;
+}
+
+
+int64_t MetricHeapOldExternal::Value() const {
+  ASSERT(isolate() == Isolate::Current());
+  return isolate()->heap()->ExternalInWords(Heap::kOld) * kWordSize;
+}
+
+
+int64_t MetricHeapNewUsed::Value() const {
+  ASSERT(isolate() == Isolate::Current());
+  return isolate()->heap()->UsedInWords(Heap::kNew) * kWordSize;
+}
+
+
+int64_t MetricHeapNewCapacity::Value() const {
+  ASSERT(isolate() == Isolate::Current());
+  return isolate()->heap()->CapacityInWords(Heap::kNew) * kWordSize;
+}
+
+
+int64_t MetricHeapNewExternal::Value() const {
+  ASSERT(isolate() == Isolate::Current());
+  return isolate()->heap()->ExternalInWords(Heap::kNew) * kWordSize;
+}
+
+
+int64_t MetricIsolateCount::Value() const {
+  return Isolate::IsolateListLength();
+}
+
+#define VM_METRIC_VARIABLE(type, variable, name, unit)                         \
+  static type vm_metric_##variable##_;
+  VM_METRIC_LIST(VM_METRIC_VARIABLE);
+#undef VM_METRIC_VARIABLE
+
+
+void Metric::InitOnce() {
+#define VM_METRIC_INIT(type, variable, name, unit)                             \
+  vm_metric_##variable##_.Init(name, NULL, Metric::unit);
+  VM_METRIC_LIST(VM_METRIC_INIT);
+#undef VM_METRIC_INIT
+}
+
+}  // namespace dart