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..1814d400390b6a460aa7b554f1e778d310adccbd 100644
--- a/media/video/capture/linux/v4l2_capture_delegate.h
+++ b/media/video/capture/linux/v4l2_capture_delegate.h
@@ -28,6 +28,7 @@ class V4L2CaptureDelegate
   static scoped_refptr<V4L2CaptureDelegate> CreateV4L2CaptureDelegate(
       const VideoCaptureDevice::Name& device_name,
       const scoped_refptr<base::SingleThreadTaskRunner>& v4l2_task_runner,
+      VideoCaptureDevice::Client* client,
       int power_line_frequency);
 
   // Retrieves the #planes for a given |fourcc|, or 0 if unknown.
@@ -49,22 +50,27 @@ 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 {
       DCHECK_LT(plane, planes_.size());
       return planes_[plane].start;
     }
+    int const GetFd(size_t plane) const {

[Pawel Osciak, 2015/06/15 10:34:55]

GetPlaneFd()

Also, please add an empty line above.

[mcasas, 2015/06/17 01:30:53]

Done.

+      DCHECK_LT(plane, planes_.size());
+      return planes_[plane].fd;
+    }
 
     size_t GetPlanePayloadSize(size_t plane) const {
       DCHECK_LT(plane, planes_.size());
@@ -82,12 +88,16 @@ 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|, for non mappable resources (dma-buf).
     struct Plane {
       uint8_t* start;
       size_t length;
       size_t payload_size;
+      int fd;
     };
     std::vector<Plane> planes_;
   };
@@ -107,8 +117,15 @@ 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;
+
+  // Finish filling in |request| with DmaBuf or normal buffers.
+  virtual void FinishFillingV4L2RequestBuffers(

[Pawel Osciak, 2015/06/15 10:34:55]

This could just be a simple memory_type() const getter, especially since
memory_type_ should be a member of V4L2CaptureDelegate (please see my comment
later on).

[mcasas, 2015/06/17 01:30:53]

Done.

+      v4l2_requestbuffers* request) const = 0;
 
   // Fetch the number of bytes occupied by data in |buffer| and set to
   // |buffer_tracker|.
@@ -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);