Revert of Revert "Remove CpuMonitor and related, unused, code."

webrtc/base/cpumonitor.h

-/*
- *  Copyright 2010 The WebRTC Project Authors. All rights reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef WEBRTC_BASE_CPUMONITOR_H_
-#define WEBRTC_BASE_CPUMONITOR_H_
-
-#include "webrtc/base/basictypes.h"
-#include "webrtc/base/messagehandler.h"
-#include "webrtc/base/scoped_ptr.h"
-#include "webrtc/base/sigslot.h"
-#if defined(WEBRTC_LINUX)
-#include "webrtc/base/stream.h"
-#endif // defined(WEBRTC_LINUX)
-
-namespace rtc {
-class Thread;
-class SystemInfo;
-
-struct CpuStats {
-  CpuStats()
-      : prev_total_times_(0),
-        prev_cpu_times_(0),
-        prev_load_(0.f),
-        prev_load_time_(0u) {
-  }
-
-  uint64 prev_total_times_;
-  uint64 prev_cpu_times_;
-  float prev_load_;  // Previous load value.
-  uint32 prev_load_time_;  // Time previous load value was taken.
-};
-
-// CpuSampler samples the process and system load.
-class CpuSampler {
- public:
-  CpuSampler();
-  ~CpuSampler();
-
-  // Initialize CpuSampler.  Returns true if successful.
-  bool Init();
-
-  // Set minimum interval in ms between computing new load values.
-  // Default 950 ms.  Set to 0 to disable interval.
-  void set_load_interval(int min_load_interval);
-
-  // Return CPU load of current process as a float from 0 to 1.
-  float GetProcessLoad();
-
-  // Return CPU load of current process as a float from 0 to 1.
-  float GetSystemLoad();
-
-  // Return number of cpus. Includes hyperthreads.
-  int GetMaxCpus() const;
-
-  // Return current number of cpus available to this process.
-  int GetCurrentCpus();
-
-  // For testing. Allows forcing of fallback to using NTDLL functions.
-  void set_force_fallback(bool fallback) {
-#if defined(WEBRTC_WIN)
-    force_fallback_ = fallback;
-#endif
-  }
-
- private:
-  float UpdateCpuLoad(uint64 current_total_times,
-                      uint64 current_cpu_times,
-                      uint64 *prev_total_times,
-                      uint64 *prev_cpu_times);
-  CpuStats process_;
-  CpuStats system_;
-  int cpus_;
-  int min_load_interval_;  // Minimum time between computing new load.
-  scoped_ptr<SystemInfo> sysinfo_;
-#if defined(WEBRTC_WIN)
-  void* get_system_times_;
-  void* nt_query_system_information_;
-  bool force_fallback_;
-#endif
-#if defined(WEBRTC_LINUX)
-  // File for reading /proc/stat
-  scoped_ptr<FileStream> sfile_;
-#endif // defined(WEBRTC_LINUX)
-};
-
-// CpuMonitor samples and signals the CPU load periodically.
-class CpuMonitor
-    : public rtc::MessageHandler, public sigslot::has_slots<> {
- public:
-  explicit CpuMonitor(Thread* thread);
-  ~CpuMonitor() override;
-  void set_thread(Thread* thread);
-
-  bool Start(int period_ms);
-  void Stop();
-  // Signal parameters are current cpus, max cpus, process load and system load.
-  sigslot::signal4<int, int, float, float> SignalUpdate;
-
- protected:
-  // Override virtual method of parent MessageHandler.
-  void OnMessage(rtc::Message* msg) override;
-  // Clear the monitor thread and stop sending it messages if the thread goes
-  // away before our lifetime.
-  void OnMessageQueueDestroyed() { monitor_thread_ = NULL; }
-
- private:
-  Thread* monitor_thread_;
-  CpuSampler sampler_;
-  int period_ms_;
-
-  DISALLOW_COPY_AND_ASSIGN(CpuMonitor);
-};
-
-}  // namespace rtc
-
-#endif  // WEBRTC_BASE_CPUMONITOR_H_