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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // Implementation of a fake VideoCaptureDevice class. Used for testing other
      6 // video capture classes when no real hardware is available.
      7 
      8 #ifndef MEDIA_VIDEO_CAPTURE_FAKE_VIDEO_CAPTURE_DEVICE_H_
      9 #define MEDIA_VIDEO_CAPTURE_FAKE_VIDEO_CAPTURE_DEVICE_H_
     10 
     11 #include <string>
     12 
     13 #include "base/atomicops.h"
     14 #include "base/memory/scoped_ptr.h"
     15 #include "base/threading/thread.h"
     16 #include "base/threading/thread_checker.h"
     17 #include "media/video/capture/video_capture_device.h"
     18 
     19 namespace media {
     20 
     21 class MEDIA_EXPORT FakeVideoCaptureDevice : public VideoCaptureDevice {
     22  public:
     23   static VideoCaptureDevice* Create(const Name& device_name);
     24   virtual ~FakeVideoCaptureDevice();
     25   // Used for testing. This will make sure the next call to Create will
     26   // return NULL;
     27   static void SetFailNextCreate();
     28   static void SetNumberOfFakeDevices(size_t number_of_devices);
     29   static size_t NumberOfFakeDevices();
     30 
     31   static void GetDeviceNames(Names* device_names);
     32   static void GetDeviceSupportedFormats(const Name& device,
     33                                         VideoCaptureFormats* supported_formats);
     34 
     35   // VideoCaptureDevice implementation.
     36   virtual void AllocateAndStart(const VideoCaptureParams& params,
     37                                 scoped_ptr<VideoCaptureDevice::Client> client)
     38       OVERRIDE;
     39   virtual void StopAndDeAllocate() OVERRIDE;
     40 
     41  private:
     42   FakeVideoCaptureDevice();
     43 
     44   // Called on the |capture_thread_| only.
     45   void OnAllocateAndStart(const VideoCaptureParams& params,
     46                           scoped_ptr<Client> client);
     47   void OnStopAndDeAllocate();
     48   void OnCaptureTask();
     49   void Reallocate();
     50   void PopulateFormatRoster();
     51 
     52   // |thread_checker_| is used to check that destructor, AllocateAndStart() and
     53   // StopAndDeAllocate() are called in the correct thread that owns the object.
     54   base::ThreadChecker thread_checker_;
     55 
     56   base::Thread capture_thread_;
     57   // The following members are only used on the |capture_thread_|.
     58   scoped_ptr<VideoCaptureDevice::Client> client_;
     59   scoped_ptr<uint8[]> fake_frame_;
     60   int frame_count_;
     61   VideoCaptureFormat capture_format_;
     62 
     63   // When the device is allowed to change resolution, this vector holds the
     64   // available ones which are used in sequence, restarting at the end. These
     65   // two members belong to and are only used in |capture_thread_|.
     66   std::vector<VideoCaptureFormat> format_roster_;
     67   int format_roster_index_;
     68 
     69   static bool fail_next_create_;
     70   // |number_of_devices_| is atomic since tests can call SetNumberOfFakeDevices
     71   // on the IO thread to set |number_of_devices_|. The variable can be
     72   // read from a separate thread.
     73   // TODO(perkj): Make tests independent of global state. crbug/323913
     74   static base::subtle::Atomic32 number_of_devices_;
     75 
     76   DISALLOW_COPY_AND_ASSIGN(FakeVideoCaptureDevice);
     77 };
     78 
     79 }  // namespace media
     80 
     81 #endif  // MEDIA_VIDEO_CAPTURE_FAKE_VIDEO_CAPTURE_DEVICE_H_
     82