Add separate base classes for I420 and I444 buffers

Previously, the base class PlanarYuvBuffer was used directly. Having
separate base classes will allow us to improve type safety in some
places.

BUG=webrtc:7632
TBR=stefan@webrtc.org

Review-Url: https://codereview.webrtc.org/2914463002
Cr-Commit-Position: refs/heads/master@{#18317}

webrtc/api/video/i420_buffer.cc

@@ -136,10 +136,6 @@ void I420Buffer::InitializeData() {
          I420DataSize(height_, stride_y_, stride_u_, stride_v_));
 }
 
-VideoFrameBuffer::Type I420Buffer::type() const {
-  return Type::kI420;
-}
-
 int I420Buffer::width() const {
   return width_;
 }

webrtc/api/video/i420_buffer.h

@@ -20,7 +20,7 @@
 namespace webrtc {
 
 // Plain I420 buffer in standard memory.
-class I420Buffer : public PlanarYuvBuffer {
+class I420Buffer : public I420BufferInterface {
  public:
   static rtc::scoped_refptr<I420Buffer> Create(int width, int height);
   static rtc::scoped_refptr<I420Buffer> Create(int width,
@@ -53,7 +53,6 @@ class I420Buffer : public PlanarYuvBuffer {
   // are resolved in a better way. Or in the mean time, use SetBlack.
   void InitializeData();
 
-  Type type() const override;
   int width() const override;
   int height() const override;
   const uint8_t* DataY() const override;

webrtc/api/video/video_frame_buffer.cc

@@ -10,7 +10,7 @@
 
 #include "webrtc/api/video/video_frame_buffer.h"
 
-#include "libyuv/convert_from.h"
+#include "libyuv/convert.h"
 #include "webrtc/api/video/i420_buffer.h"
 #include "webrtc/base/checks.h"
 
@@ -21,16 +21,14 @@ namespace {
 // TODO(magjed): Remove this class. It is only used for providing a default
 // implementation of ToI420() until external clients are updated. ToI420() will
 // then be made pure virtual. This adapter adapts a VideoFrameBuffer (which is
-// expected to be in I420 format) to the PlanarYuvBuffer interface. The reason
-// this is needed is because of the return type mismatch in NativeToI420Buffer
-// (returns VideoFrameBuffer) vs ToI420 (returns PlanarYuvBuffer).
-class PlanarYuvBufferAdapter : public PlanarYuvBuffer {
+// expected to be in I420 format) to I420BufferInterface. The reason this is
+// needed is because of the return type mismatch in NativeToI420Buffer (returns
+// VideoFrameBuffer) vs ToI420 (returns I420BufferInterface).
+class I420InterfaceAdapter : public I420BufferInterface {
  public:
-  explicit PlanarYuvBufferAdapter(rtc::scoped_refptr<VideoFrameBuffer> buffer)
+  explicit I420InterfaceAdapter(rtc::scoped_refptr<VideoFrameBuffer> buffer)
       : buffer_(buffer) {}
 
-  Type type() const override { return Type::kI420; }
-
   int width() const override { return buffer_->width(); }
   int height() const override { return buffer_->height(); }
 
@@ -89,65 +87,59 @@ rtc::scoped_refptr<VideoFrameBuffer> VideoFrameBuffer::NativeToI420Buffer() {
   return ToI420();
 }
 
-rtc::scoped_refptr<PlanarYuvBuffer> VideoFrameBuffer::ToI420() {
-  return new rtc::RefCountedObject<PlanarYuvBufferAdapter>(
-      NativeToI420Buffer());
+rtc::scoped_refptr<I420BufferInterface> VideoFrameBuffer::ToI420() {
+  return new rtc::RefCountedObject<I420InterfaceAdapter>(NativeToI420Buffer());
 }
 
-rtc::scoped_refptr<PlanarYuvBuffer> VideoFrameBuffer::GetI420() {
+rtc::scoped_refptr<I420BufferInterface> VideoFrameBuffer::GetI420() {
   RTC_CHECK(type() == Type::kI420);
-  // TODO(magjed): static_cast to PlanarYuvBuffer instead once external clients
-  // are updated.
-  return new rtc::RefCountedObject<PlanarYuvBufferAdapter>(this);
+  // TODO(magjed): static_cast to I420BufferInterface instead once external
+  // clients are updated.
+  return new rtc::RefCountedObject<I420InterfaceAdapter>(this);
 }
 
-rtc::scoped_refptr<PlanarYuvBuffer> VideoFrameBuffer::GetI444() {
+rtc::scoped_refptr<I444BufferInterface> VideoFrameBuffer::GetI444() {
   RTC_CHECK(type() == Type::kI444);
-  return static_cast<PlanarYuvBuffer*>(this);
+  return static_cast<I444BufferInterface*>(this);
 }
 
-rtc::scoped_refptr<PlanarYuvBuffer> PlanarYuvBuffer::ToI420() {
-  switch (type()) {
-    case Type::kI420:
-      return this;
-    case Type::kI444: {
-      rtc::scoped_refptr<I420Buffer> i420_buffer =
-          I420Buffer::Create(width(), height());
-      libyuv::I420ToI444(DataY(), StrideY(), DataU(), StrideU(), DataV(),
-                         StrideV(), i420_buffer->MutableDataY(),
-                         i420_buffer->StrideY(), i420_buffer->MutableDataU(),
-                         i420_buffer->StrideU(), i420_buffer->MutableDataV(),
-                         i420_buffer->StrideV(), width(), height());
-      return i420_buffer;
-    }
-    default:
-      RTC_NOTREACHED();
-      return nullptr;
-  }
+VideoFrameBuffer::Type I420BufferInterface::type() const {
+  return Type::kI420;
 }
 
-int PlanarYuvBuffer::ChromaWidth() const {
-  switch (type()) {
-    case Type::kI420:
-      return (width() + 1) / 2;
-    case Type::kI444:
-      return width();
-    default:
-      RTC_NOTREACHED();
-      return 0;
-  }
+int I420BufferInterface::ChromaWidth() const {
+  return (width() + 1) / 2;
 }
 
-int PlanarYuvBuffer::ChromaHeight() const {
-  switch (type()) {
-    case Type::kI420:
-      return (height() + 1) / 2;
-    case Type::kI444:
-      return height();
-    default:
-      RTC_NOTREACHED();
-      return 0;
-  }
+int I420BufferInterface::ChromaHeight() const {
+  return (height() + 1) / 2;
+}
+
+rtc::scoped_refptr<I420BufferInterface> I420BufferInterface::ToI420() {
+  return this;
+}
+
+VideoFrameBuffer::Type I444BufferInterface::type() const {
+  return Type::kI444;
+}
+
+int I444BufferInterface::ChromaWidth() const {
+  return width();
+}
+
+int I444BufferInterface::ChromaHeight() const {
+  return height();
+}
+
+rtc::scoped_refptr<I420BufferInterface> I444BufferInterface::ToI420() {
+  rtc::scoped_refptr<I420Buffer> i420_buffer =
+      I420Buffer::Create(width(), height());
+  libyuv::I444ToI420(DataY(), StrideY(), DataU(), StrideU(), DataV(), StrideV(),
+                     i420_buffer->MutableDataY(), i420_buffer->StrideY(),
+                     i420_buffer->MutableDataU(), i420_buffer->StrideU(),
+                     i420_buffer->MutableDataV(), i420_buffer->StrideV(),
+                     width(), height());
+  return i420_buffer;
 }
 
 }  // namespace webrtc

webrtc/api/video/video_frame_buffer.h

@@ -18,7 +18,8 @@
 
 namespace webrtc {
 
-class PlanarYuvBuffer;
+class I420BufferInterface;
+class I444BufferInterface;
 
 // Base class for frame buffers of different types of pixel format and storage.
 // The tag in type() indicates how the data is represented, and each type is
@@ -58,12 +59,12 @@ class VideoFrameBuffer : public rtc::RefCountInterface {
   // in another format, a conversion will take place. All implementations must
   // provide a fallback to I420 for compatibility with e.g. the internal WebRTC
   // software encoders.
-  virtual rtc::scoped_refptr<PlanarYuvBuffer> ToI420();
+  virtual rtc::scoped_refptr<I420BufferInterface> ToI420();
 
   // These functions should only be called if type() is of the correct type.
   // Calling with a different type will result in a crash.
-  rtc::scoped_refptr<PlanarYuvBuffer> GetI420();
-  rtc::scoped_refptr<PlanarYuvBuffer> GetI444();
+  rtc::scoped_refptr<I420BufferInterface> GetI420();
+  rtc::scoped_refptr<I444BufferInterface> GetI444();
 
   // Deprecated - use ToI420() first instead.
   // Returns pointer to the pixel data for a given plane. The memory is owned by
@@ -92,8 +93,8 @@ class VideoFrameBuffer : public rtc::RefCountInterface {
 // This interface represents Type::kI420 and Type::kI444.
 class PlanarYuvBuffer : public VideoFrameBuffer {
  public:
-  int ChromaWidth() const;
-  int ChromaHeight() const;
+  virtual int ChromaWidth() const = 0;
+  virtual int ChromaHeight() const = 0;
 
   // Returns pointer to the pixel data for a given plane. The memory is owned by
   // the VideoFrameBuffer object and must not be freed by the caller.
@@ -106,12 +107,36 @@ class PlanarYuvBuffer : public VideoFrameBuffer {
   int StrideU() const override = 0;
   int StrideV() const override = 0;
 
-  rtc::scoped_refptr<PlanarYuvBuffer> ToI420() override;
-
  protected:
   ~PlanarYuvBuffer() override {}
 };
 
+class I420BufferInterface : public PlanarYuvBuffer {
+ public:
+  Type type() const final;
+
+  int ChromaWidth() const final;
+  int ChromaHeight() const final;
+
+  rtc::scoped_refptr<I420BufferInterface> ToI420() final;
+
+ protected:
+  ~I420BufferInterface() override {}
+};
+
+class I444BufferInterface : public PlanarYuvBuffer {
+ public:
+  Type type() const final;
+
+  int ChromaWidth() const final;
+  int ChromaHeight() const final;
+
+  rtc::scoped_refptr<I420BufferInterface> ToI420() final;
+
+ protected:
+  ~I444BufferInterface() override {}
+};
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_VIDEO_VIDEO_FRAME_BUFFER_H_

webrtc/common_video/include/video_frame_buffer.h

@@ -45,7 +45,7 @@ class NativeHandleBuffer : public VideoFrameBuffer {
   const int height_;
 };
 
-class WrappedI420Buffer : public PlanarYuvBuffer {
+class WrappedI420Buffer : public I420BufferInterface {
  public:
   WrappedI420Buffer(int width,
                     int height,
@@ -56,8 +56,6 @@ class WrappedI420Buffer : public PlanarYuvBuffer {
                     const uint8_t* v_plane,
                     int v_stride,
                     const rtc::Callback0<void>& no_longer_used);
-  Type type() const override;
-
   int width() const override;
   int height() const override;
 

webrtc/common_video/video_frame_buffer.cc

@@ -96,10 +96,6 @@ WrappedI420Buffer::~WrappedI420Buffer() {
   no_longer_used_cb_();
 }
 
-VideoFrameBuffer::Type WrappedI420Buffer::type() const {
-  return Type::kI420;
-}
-
 int WrappedI420Buffer::width() const {
   return width_;
 }