VideoCaptureDeviceLinux: Add support for SPLANE+DMABUF V4L2 type capture

media/video/capture/linux/v4l2_capture_delegate.h

Index: media/video/capture/linux/v4l2_capture_delegate.h
diff --git a/media/video/capture/linux/v4l2_capture_delegate.h b/media/video/capture/linux/v4l2_capture_delegate.h
index 9d65bb248539d708bd794e883d152810fe113fd1..42777900169a863ecd19d7a6518f0414d66ed012 100644
--- a/media/video/capture/linux/v4l2_capture_delegate.h
+++ b/media/video/capture/linux/v4l2_capture_delegate.h
@@ -24,10 +24,13 @@ namespace media {
 class V4L2CaptureDelegate
     : public base::RefCountedThreadSafe<V4L2CaptureDelegate> {
  public:
-  // Creates the appropiate VideoCaptureDelegate according to parameters.
+  // Creates the appropiate VideoCaptureDelegate according to parameters. The
+  // caller instructs via |allow_using_dma_bufs| if DmaBufs should be used.
   static scoped_refptr<V4L2CaptureDelegate> CreateV4L2CaptureDelegate(
       const VideoCaptureDevice::Name& device_name,
       const scoped_refptr<base::SingleThreadTaskRunner>& v4l2_task_runner,
+      VideoCaptureDevice::Client* client,
+      bool allow_using_dma_bufs,
       int power_line_frequency);
 
   // Retrieves the #planes for a given |fourcc|, or 0 if unknown.
@@ -49,16 +52,17 @@ class V4L2CaptureDelegate
   void SetRotation(int rotation);
 
  protected:
-  // Class keeping track of SPLANE/MPLANE V4L2 buffers, mmap()ed on construction
-  // and munmap()ed on destruction. Destruction is syntactically equal for
-  // S/MPLANE but not construction, so this is implemented in derived classes.
+  // Class keeping track of SPLANE/MPLANE V4L2 buffers, mappable or not. Non
+  // mappable buffer keep track of the associated |fd|.
+  // Mappable buffers are mmap()ed on Init() and munmap()ed on destruction.
+  // Destruction is syntactically equal for S/MPLANE but not construction, so
+  // this must be implemented in derived classes.
   // Internally it has a vector of planes, which for SPLANE will contain only
   // one element.
   class BufferTracker : public base::RefCounted<BufferTracker> {
    public:
     BufferTracker();
-    // Abstract method to mmap() given |fd| according to |buffer|, planarity
-    // specific.
+    // Abstract method to init the BufferTracker according to |buffer|.
     virtual bool Init(int fd, const v4l2_buffer& buffer) = 0;
 
     uint8_t* const GetPlaneStart(size_t plane) const {
@@ -66,6 +70,11 @@ class V4L2CaptureDelegate
       return planes_[plane].start;
     }
 
+    int const GetPlaneFd(size_t plane) const {
+      DCHECK_LT(plane, planes_.size());
+      return planes_[plane].fd;
+    }
+
     size_t GetPlanePayloadSize(size_t plane) const {
       DCHECK_LT(plane, planes_.size());
       return planes_[plane].payload_size;
@@ -82,12 +91,17 @@ class V4L2CaptureDelegate
     virtual ~BufferTracker();
     // Adds a given mmap()ed plane to |planes_|.
     void AddMmapedPlane(uint8_t* const start, size_t length);
+    void AddNonMmapedPlane(int fd);
 
    private:
+    // A Plane can be composed of |start| and |length|, for mappable resources
+    // (basically, memory), or by a |fd and a |capture_buffer|, for non mappable
+    // resources (dma-buf).|length| is needed for munmap().
     struct Plane {
       uint8_t* start;
       size_t length;
       size_t payload_size;
+      int fd;
     };
     std::vector<Plane> planes_;
   };
@@ -95,6 +109,7 @@ class V4L2CaptureDelegate
   V4L2CaptureDelegate(
       const VideoCaptureDevice::Name& device_name,
       const scoped_refptr<base::SingleThreadTaskRunner>& v4l2_task_runner,
+      v4l2_memory memory_type,
       int power_line_frequency);
   virtual ~V4L2CaptureDelegate();
 
@@ -107,23 +122,25 @@ class V4L2CaptureDelegate
                               uint32_t height,
                               uint32_t pixelformat_fourcc) const = 0;
 
-  // Finish filling |buffer| struct with planarity-dependent data.
-  virtual void FinishFillingV4L2Buffer(v4l2_buffer* buffer) const = 0;
+  // Finish filling |buffer| struct with planarity-dependent data. Underlying
+  // implementation might need to know if it's for enqueueing, to allocate
+  // resources.
+  virtual void FinishFillingV4L2Buffer(v4l2_buffer* buffer,
+                                       bool for_enqueue) const = 0;
 
-  // Fetch the number of bytes occupied by data in |buffer| and set to
-  // |buffer_tracker|.
+  // Set |buffer_tracker|s payload size from |buffer|.
   virtual void SetPayloadSize(
       const scoped_refptr<BufferTracker>& buffer_tracker,
       const v4l2_buffer& buffer) const = 0;
 
   // Sends the captured |buffer| to the |client_|, synchronously.
-  virtual void SendBuffer(
-      const scoped_refptr<BufferTracker>& buffer_tracker,
-      const v4l2_format& format) const = 0;
+  virtual void SendBuffer(const scoped_refptr<BufferTracker>& buffer_tracker,
+                          const v4l2_format& format) const = 0;
 
   // A few accessors for SendBuffer()'s to access private member variables.
   VideoCaptureFormat capture_format() const { return capture_format_; }
   VideoCaptureDevice::Client* client() const { return client_.get(); }
+  v4l2_memory memory_type() const { return memory_type_; }
   int rotation() const { return rotation_; }
 
  private:
@@ -136,7 +153,7 @@ class V4L2CaptureDelegate
   bool MapAndQueueBuffer(int index);
   // Fills all common parts of |buffer|. Delegates to FinishFillingV4L2Buffer()
   // for filling in the planar-dependent parts.
-  void FillV4L2Buffer(v4l2_buffer* buffer, int i) const;
+  void FillV4L2Buffer(v4l2_buffer* buffer, int i, bool for_enqueue) const;
   void DoCapture();
   void SetErrorState(const std::string& reason);
 
@@ -151,6 +168,9 @@ class V4L2CaptureDelegate
   scoped_ptr<VideoCaptureDevice::Client> client_;
   base::ScopedFD device_fd_;
 
+  // Memory Type (DmaBuf or Mmap) configured on ctor.
+  const v4l2_memory memory_type_;
+
   // Vector of BufferTracker to keep track of mmap()ed pointers and their use.
   std::vector<scoped_refptr<BufferTracker>> buffer_tracker_pool_;