76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_SYSTEM_SYSTEM_MONITOR_H_
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#define BASE_SYSTEM_SYSTEM_MONITOR_H_
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#include "base/base_export.h"
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#include "base/macros.h"
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#include "base/memory/ref_counted.h"
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#include "base/observer_list_threadsafe.h"
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#include "build/build_config.h"
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namespace base {
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// Class for monitoring various system-related subsystems
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// such as power management, network status, etc.
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// TODO(mbelshe): Add support beyond just power management.
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class BASE_EXPORT SystemMonitor {
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public:
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// Type of devices whose change need to be monitored, such as add/remove.
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enum DeviceType {
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DEVTYPE_AUDIO, // Audio device, e.g., microphone.
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DEVTYPE_VIDEO_CAPTURE, // Video capture device, e.g., webcam.
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DEVTYPE_UNKNOWN, // Other devices.
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};
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// Create SystemMonitor. Only one SystemMonitor instance per application
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// is allowed.
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SystemMonitor();
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~SystemMonitor();
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// Get the application-wide SystemMonitor (if not present, returns NULL).
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static SystemMonitor* Get();
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class BASE_EXPORT DevicesChangedObserver {
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public:
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// Notification that the devices connected to the system have changed.
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// This is only implemented on Windows currently.
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virtual void OnDevicesChanged(DeviceType device_type) {}
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protected:
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virtual ~DevicesChangedObserver() = default;
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};
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// Add a new observer.
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// Can be called from any thread.
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// Must not be called from within a notification callback.
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void AddDevicesChangedObserver(DevicesChangedObserver* obs);
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// Remove an existing observer.
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// Can be called from any thread.
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// Must not be called from within a notification callback.
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void RemoveDevicesChangedObserver(DevicesChangedObserver* obs);
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// The ProcessFoo() style methods are a broken pattern and should not
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// be copied. Any significant addition to this class is blocked on
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// refactoring to improve the state of affairs. See http://crbug.com/149059
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// Cross-platform handling of a device change event.
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void ProcessDevicesChanged(DeviceType device_type);
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private:
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// Functions to trigger notifications.
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void NotifyDevicesChanged(DeviceType device_type);
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scoped_refptr<ObserverListThreadSafe<DevicesChangedObserver>>
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devices_changed_observer_list_;
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DISALLOW_COPY_AND_ASSIGN(SystemMonitor);
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};
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} // namespace base
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#endif // BASE_SYSTEM_SYSTEM_MONITOR_H_
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