Introduce CpuUsageData class

This change introduces the CpuUsageData and accompanying tests.

Bug: 1128204
Change-Id: I401b4884be3cac434196da1ab35977c9e8866e3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2522055
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Auto-Submit: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824939}

chromeos/components/diagnostics_ui/backend/BUILD.gn

@@ -6,6 +6,8 @@ assert(is_chromeos, "Non-ChromeOS builds cannot depend on //chromeos")
 
 static_library("backend") {
   sources = [
+    "cpu_usage_data.cc",
+    "cpu_usage_data.h",
     "cros_healthd_helpers.cc",
     "cros_healthd_helpers.h",
     "diagnostics_manager.cc",
@@ -32,6 +34,7 @@ source_set("unit_tests") {
   testonly = true
 
   sources = [
+    "cpu_usage_data_unittest.cc",
     "power_manager_client_conversions_unittest.cc",
     "system_data_provider_unittest.cc",
     "system_routine_controller_unittest.cc",

chromeos/components/diagnostics_ui/backend/cpu_usage_data.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chromeos/components/diagnostics_ui/backend/cpu_usage_data.h"
+
+namespace chromeos {
+namespace diagnostics {
+
+CpuUsageData::CpuUsageData(uint64_t user_time,
+                           uint64_t system_time,
+                           uint64_t idle_time)
+    : user_time_(user_time), system_time_(system_time), idle_time_(idle_time) {}
+
+bool CpuUsageData::IsInitialized() const {
+  return user_time_ != std::numeric_limits<uint64_t>::max() &&
+         system_time_ != std::numeric_limits<uint64_t>::max() &&
+         idle_time_ != std::numeric_limits<uint64_t>::max();
+}
+
+uint64_t CpuUsageData::GetTotalTime() const {
+  return user_time_ + system_time_ + idle_time_;
+}
+
+CpuUsageData CpuUsageData::operator+(const CpuUsageData& other) const {
+  return CpuUsageData(user_time_ + other.user_time_,
+                      system_time_ + other.system_time_,
+                      idle_time_ + other.idle_time_);
+}
+
+CpuUsageData& CpuUsageData::operator+=(const CpuUsageData& other) {
+  user_time_ += other.user_time_;
+  system_time_ += other.system_time_;
+  idle_time_ += other.idle_time_;
+  return *this;
+}
+
+CpuUsageData CpuUsageData::operator-(const CpuUsageData& other) const {
+  return CpuUsageData(user_time_ - other.user_time_,
+                      system_time_ - other.system_time_,
+                      idle_time_ - other.idle_time_);
+}
+
+CpuUsageData& CpuUsageData::operator-=(const CpuUsageData& other) {
+  user_time_ -= other.user_time_;
+  system_time_ -= other.system_time_;
+  idle_time_ -= other.idle_time_;
+  return *this;
+}
+
+}  // namespace diagnostics
+}  // namespace chromeos

chromeos/components/diagnostics_ui/backend/cpu_usage_data.h

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_COMPONENTS_DIAGNOSTICS_UI_BACKEND_CPU_USAGE_DATA_H_
+#define CHROMEOS_COMPONENTS_DIAGNOSTICS_UI_BACKEND_CPU_USAGE_DATA_H_
+
+#include <cstdint>
+#include <limits>
+
+namespace chromeos {
+namespace diagnostics {
+
+class CpuUsageData {
+ public:
+  CpuUsageData() = default;
+  CpuUsageData(uint64_t user_time, uint64_t system_time, uint64_t idle_time);
+
+  ~CpuUsageData() = default;
+
+  CpuUsageData(const CpuUsageData& other) = default;
+  CpuUsageData& operator=(const CpuUsageData& other) = default;
+
+  bool IsInitialized() const;
+
+  uint64_t GetUserTime() const { return user_time_; }
+
+  uint64_t GetSystemTime() const { return system_time_; }
+
+  uint64_t GetIdleTime() const { return idle_time_; }
+
+  uint64_t GetTotalTime() const;
+
+  CpuUsageData operator+(const CpuUsageData& other) const;
+  CpuUsageData& operator+=(const CpuUsageData& other);
+  CpuUsageData operator-(const CpuUsageData& other) const;
+  CpuUsageData& operator-=(const CpuUsageData& other);
+
+ private:
+  uint64_t user_time_ = std::numeric_limits<uint64_t>::max();
+  uint64_t system_time_ = std::numeric_limits<uint64_t>::max();
+  uint64_t idle_time_ = std::numeric_limits<uint64_t>::max();
+};
+
+}  // namespace diagnostics
+}  // namespace chromeos
+
+#endif  // CHROMEOS_COMPONENTS_DIAGNOSTICS_UI_BACKEND_CPU_USAGE_DATA_H_

chromeos/components/diagnostics_ui/backend/cpu_usage_data_unittest.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chromeos/components/diagnostics_ui/backend/cpu_usage_data.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chromeos {
+namespace diagnostics {
+
+class CpuUsageDataTest : public testing::Test {
+ public:
+  CpuUsageDataTest() = default;
+  ~CpuUsageDataTest() override = default;
+};
+
+TEST_F(CpuUsageDataTest, Initialized) {
+  CpuUsageData data;
+
+  EXPECT_FALSE(data.IsInitialized());
+
+  data = CpuUsageData(1, 2, 3);
+
+  EXPECT_TRUE(data.IsInitialized());
+}
+
+TEST_F(CpuUsageDataTest, Total) {
+  CpuUsageData data(1, 2, 3);
+
+  EXPECT_EQ(6u, data.GetTotalTime());
+}
+
+TEST_F(CpuUsageDataTest, Addition) {
+  CpuUsageData data_1(1, 2, 3);
+  CpuUsageData data_2(4, 5, 6);
+
+  CpuUsageData data_3 = data_1 + data_2;
+
+  EXPECT_EQ(5u, data_3.GetUserTime());
+  EXPECT_EQ(7u, data_3.GetSystemTime());
+  EXPECT_EQ(9u, data_3.GetIdleTime());
+}
+
+TEST_F(CpuUsageDataTest, CompoundAddition) {
+  CpuUsageData data_1(1, 2, 3);
+  CpuUsageData data_2(4, 5, 6);
+
+  data_1 += data_2;
+
+  EXPECT_EQ(5u, data_1.GetUserTime());
+  EXPECT_EQ(7u, data_1.GetSystemTime());
+  EXPECT_EQ(9u, data_1.GetIdleTime());
+}
+
+TEST_F(CpuUsageDataTest, Subtraction) {
+  CpuUsageData data_1(1, 2, 3);
+  CpuUsageData data_2(4, 5, 6);
+
+  CpuUsageData data_3 = data_2 - data_1;
+
+  EXPECT_EQ(3u, data_3.GetUserTime());
+  EXPECT_EQ(3u, data_3.GetSystemTime());
+  EXPECT_EQ(3u, data_3.GetIdleTime());
+}
+
+TEST_F(CpuUsageDataTest, CompoundSubtraction) {
+  CpuUsageData data_1(1, 2, 3);
+  CpuUsageData data_2(4, 5, 6);
+
+  data_2 -= data_1;
+
+  EXPECT_EQ(3u, data_2.GetUserTime());
+  EXPECT_EQ(3u, data_2.GetSystemTime());
+  EXPECT_EQ(3u, data_2.GetIdleTime());
+}
+
+}  // namespace diagnostics
+}  // namespace chromeos