| // Copyright 2013 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 MEDIA_BASE_USER_INPUT_MONITOR_H_ |
| #define MEDIA_BASE_USER_INPUT_MONITOR_H_ |
| |
| #include <stddef.h> |
| |
| #include <memory> |
| |
| #include "base/macros.h" |
| #include "base/memory/read_only_shared_memory_region.h" |
| #include "base/memory/ref_counted.h" |
| #include "base/synchronization/lock.h" |
| #include "media/base/media_export.h" |
| |
| namespace base { |
| class SingleThreadTaskRunner; |
| } // namespace base |
| |
| namespace media { |
| |
| // Utility functions for correctly and atomically reading from/writing to a |
| // shared memory mapping containing key press count. |
| uint32_t MEDIA_EXPORT |
| ReadKeyPressMonitorCount(const base::ReadOnlySharedMemoryMapping& shmem); |
| void MEDIA_EXPORT |
| WriteKeyPressMonitorCount(const base::WritableSharedMemoryMapping& shmem, |
| uint32_t count); |
| |
| // Base class for audio:: and media:: UserInputMonitor implementations. |
| class MEDIA_EXPORT UserInputMonitor { |
| public: |
| UserInputMonitor(); |
| virtual ~UserInputMonitor(); |
| |
| // Creates a platform-specific instance of UserInputMonitorBase. |
| // |io_task_runner| is the task runner for an IO thread. |
| // |ui_task_runner| is the task runner for a UI thread. |
| static std::unique_ptr<UserInputMonitor> Create( |
| scoped_refptr<base::SingleThreadTaskRunner> io_task_runner, |
| scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner); |
| |
| virtual void EnableKeyPressMonitoring() = 0; |
| virtual void DisableKeyPressMonitoring() = 0; |
| |
| // Returns the number of keypresses. The starting point from when it is |
| // counted is not guaranteed, but consistent within the pair of calls of |
| // EnableKeyPressMonitoring and DisableKeyPressMonitoring. So a caller can |
| // use the difference between the values returned at two times to get the |
| // number of keypresses happened within that time period, but should not make |
| // any assumption on the initial value. |
| virtual uint32_t GetKeyPressCount() const = 0; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(UserInputMonitor); |
| }; |
| |
| // Monitors and notifies about keyboard events. |
| class MEDIA_EXPORT UserInputMonitorBase : public UserInputMonitor { |
| public: |
| UserInputMonitorBase(); |
| ~UserInputMonitorBase() override; |
| |
| // A caller must call EnableKeyPressMonitoring(WithMapping) and |
| // DisableKeyPressMonitoring in pair on the same sequence. |
| void EnableKeyPressMonitoring() override; |
| void DisableKeyPressMonitoring() override; |
| |
| // Initializes a MappedReadOnlyRegion storing key press count. Returns a |
| // readonly region to the mapping and passes the writable mapping to platform |
| // specific implementation, to update key press count. If monitoring is |
| // already enabled, it only returns a handle to readonly region. |
| base::ReadOnlySharedMemoryRegion EnableKeyPressMonitoringWithMapping(); |
| |
| private: |
| virtual void StartKeyboardMonitoring() = 0; |
| virtual void StartKeyboardMonitoring( |
| base::WritableSharedMemoryMapping mapping) = 0; |
| virtual void StopKeyboardMonitoring() = 0; |
| |
| size_t references_ = 0; |
| base::ReadOnlySharedMemoryRegion key_press_count_region_; |
| |
| SEQUENCE_CHECKER(owning_sequence_); |
| |
| DISALLOW_COPY_AND_ASSIGN(UserInputMonitorBase); |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_USER_INPUT_MONITOR_H_ |