[vulkan] remove unnecessary Result returns. (#412)

This CL removes the Result returns from methods which always return
success.

13 files changed, 22 insertions, 31 deletions

diff --git a/src/vulkan/buffer_descriptor.cc b/src/vulkan/buffer_descriptor.cc
index 360adb6..f25c61e 100644
--- a/src/vulkan/buffer_descriptor.cc
+++ b/src/vulkan/buffer_descriptor.cc
@@ -85,7 +85,8 @@ Result BufferDescriptor::RecordCopyDataToHost(CommandBuffer* command) {
         "Vulkan: BufferDescriptor::RecordCopyDataToHost() no transfer buffer");
   }
 
-  return transfer_buffer_->CopyToHost(command);
+  transfer_buffer_->CopyToHost(command);
+  return {};
 }
 
 Result BufferDescriptor::MoveResourceToBufferOutput() {
diff --git a/src/vulkan/frame_buffer.cc b/src/vulkan/frame_buffer.cc
index da89331..982800b 100644
--- a/src/vulkan/frame_buffer.cc
+++ b/src/vulkan/frame_buffer.cc
@@ -174,14 +174,11 @@ Result FrameBuffer::ChangeFrameImageLayout(CommandBuffer* command,
   return {};
 }
 
-Result FrameBuffer::CopyColorImagesToHost(CommandBuffer* command) {
+void FrameBuffer::CopyColorImagesToHost(CommandBuffer* command) {
   for (auto& img : color_images_) {
     ChangeFrameImageLayout(command, FrameImageState::kProbe);
-    Result r = img->CopyToHost(command);
-    if (!r.IsSuccess())
-      return r;
+    img->CopyToHost(command);
   }
-  return {};
 }
 
 void FrameBuffer::CopyImagesToBuffers() {
diff --git a/src/vulkan/frame_buffer.h b/src/vulkan/frame_buffer.h
index 0999982..ed32d52 100644
--- a/src/vulkan/frame_buffer.h
+++ b/src/vulkan/frame_buffer.h
@@ -56,7 +56,7 @@ class FrameBuffer {
   // Only record the command for copying the image that backs this
   // framebuffer to the host accessible buffer. The actual submission
   // of the command must be done later.
-  Result CopyColorImagesToHost(CommandBuffer* command);
+  void CopyColorImagesToHost(CommandBuffer* command);
 
   void CopyImagesToBuffers();
 
diff --git a/src/vulkan/graphics_pipeline.cc b/src/vulkan/graphics_pipeline.cc
index b9f7736..3102cb3 100644
--- a/src/vulkan/graphics_pipeline.cc
+++ b/src/vulkan/graphics_pipeline.cc
@@ -815,11 +815,9 @@ Result GraphicsPipeline::ClearBuffer(const VkClearValue& clear_value,
         command_->GetVkCommandBuffer(), 1, &clear_attachment, 1, &clear_rect);
   }
 
-  Result r = frame_->CopyColorImagesToHost(command_.get());
-  if (!r.IsSuccess())
-    return r;
+  frame_->CopyColorImagesToHost(command_.get());
 
-  r = cmd_buf_guard.Submit(GetFenceTimeout());
+  Result r = cmd_buf_guard.Submit(GetFenceTimeout());
   if (!r.IsSuccess())
     return r;
 
@@ -907,9 +905,7 @@ Result GraphicsPipeline::Draw(const DrawArraysCommand* command,
       }
     }
 
-    r = frame_->CopyColorImagesToHost(command_.get());
-    if (!r.IsSuccess())
-      return r;
+    frame_->CopyColorImagesToHost(command_.get());
 
     r = cmd_buf_guard.Submit(GetFenceTimeout());
     if (!r.IsSuccess())
diff --git a/src/vulkan/index_buffer.cc b/src/vulkan/index_buffer.cc
index 625a40b..a3c10d3 100644
--- a/src/vulkan/index_buffer.cc
+++ b/src/vulkan/index_buffer.cc
@@ -50,7 +50,8 @@ Result IndexBuffer::SendIndexData(
   std::memcpy(transfer_buffer_->HostAccessibleMemoryPtr(),
               buffer->ValuePtr()->data(), buffer->GetSizeInBytes());
 
-  return transfer_buffer_->CopyToDevice(command);
+  transfer_buffer_->CopyToDevice(command);
+  return {};
 }
 
 Result IndexBuffer::BindToCommandBuffer(CommandBuffer* command) {
diff --git a/src/vulkan/resource.cc b/src/vulkan/resource.cc
index 697c066..154328b 100644
--- a/src/vulkan/resource.cc
+++ b/src/vulkan/resource.cc
@@ -105,7 +105,7 @@ Resource::Resource(Device* device,
 Resource::~Resource() = default;
 
 Result Resource::CreateVkBuffer(VkBuffer* buffer, VkBufferUsageFlags usage) {
-  if (buffer == nullptr)
+  if (!buffer)
     return Result("Vulkan::Given VkBuffer pointer is nullptr");
 
   VkBufferCreateInfo buffer_info = VkBufferCreateInfo();
diff --git a/src/vulkan/resource.h b/src/vulkan/resource.h
index 24462c9..8a9e07e 100644
--- a/src/vulkan/resource.h
+++ b/src/vulkan/resource.h
@@ -47,7 +47,7 @@ class Resource {
  public:
   virtual ~Resource();
 
-  virtual Result CopyToHost(CommandBuffer* command) = 0;
+  virtual void CopyToHost(CommandBuffer* command) = 0;
 
   void* HostAccessibleMemoryPtr() const { return memory_ptr_; }
 
diff --git a/src/vulkan/transfer_buffer.cc b/src/vulkan/transfer_buffer.cc
index f361db1..1db1893 100644
--- a/src/vulkan/transfer_buffer.cc
+++ b/src/vulkan/transfer_buffer.cc
@@ -100,18 +100,16 @@ Result TransferBuffer::CreateVkBufferView(VkFormat format) {
   return {};
 }
 
-Result TransferBuffer::CopyToDevice(CommandBuffer* command) {
+void TransferBuffer::CopyToDevice(CommandBuffer* command) {
   // This is redundant because this buffer is always host visible
   // and coherent and vkQueueSubmit will make writes from host
-  // avaliable (See chapter 6.9. "Host Write Ordering Guarantees" in
+  // available (See chapter 6.9. "Host Write Ordering Guarantees" in
   // Vulkan spec), but we prefer to keep it to simplify our own code.
   MemoryBarrier(command);
-  return {};
 }
 
-Result TransferBuffer::CopyToHost(CommandBuffer* command) {
+void TransferBuffer::CopyToHost(CommandBuffer* command) {
   MemoryBarrier(command);
-  return {};
 }
 
 void TransferBuffer::UpdateMemoryWithRawData(
diff --git a/src/vulkan/transfer_buffer.h b/src/vulkan/transfer_buffer.h
index 61ea89b..09226bc 100644
--- a/src/vulkan/transfer_buffer.h
+++ b/src/vulkan/transfer_buffer.h
@@ -51,7 +51,7 @@ class TransferBuffer : public Resource {
   // Since |buffer_| is mapped to host accessible and host coherent
   // memory |memory_|, this method only conducts memory barrier to
   // make it available to device domain.
-  virtual Result CopyToDevice(CommandBuffer* command);
+  virtual void CopyToDevice(CommandBuffer* command);
 
   // Fill memory from 0 to |raw_data.size()| with |raw_data|.
   void UpdateMemoryWithRawData(const std::vector<uint8_t>& raw_data);
@@ -59,7 +59,7 @@ class TransferBuffer : public Resource {
   // Since |buffer_| is mapped to host accessible and host coherent
   // memory |memory_|, this method only conducts memory barrier to
   // make it available to host domain.
-  Result CopyToHost(CommandBuffer* command) override;
+  void CopyToHost(CommandBuffer* command) override;
 
  private:
   VkBuffer buffer_ = VK_NULL_HANDLE;
diff --git a/src/vulkan/transfer_image.cc b/src/vulkan/transfer_image.cc
index f6e334d..82857cd 100644
--- a/src/vulkan/transfer_image.cc
+++ b/src/vulkan/transfer_image.cc
@@ -157,7 +157,7 @@ Result TransferImage::CreateVkImageView() {
   return {};
 }
 
-Result TransferImage::CopyToHost(CommandBuffer* command) {
+void TransferImage::CopyToHost(CommandBuffer* command) {
   VkBufferImageCopy copy_region = VkBufferImageCopy();
   copy_region.bufferOffset = 0;
   // Row length of 0 results in tight packing of rows, so the row stride
@@ -180,7 +180,6 @@ Result TransferImage::CopyToHost(CommandBuffer* command) {
       &copy_region);
 
   MemoryBarrier(command);
-  return {};
 }
 
 void TransferImage::ChangeLayout(CommandBuffer* command,
diff --git a/src/vulkan/transfer_image.h b/src/vulkan/transfer_image.h
index 879a3eb..8e93711 100644
--- a/src/vulkan/transfer_image.h
+++ b/src/vulkan/transfer_image.h
@@ -40,8 +40,6 @@ class TransferImage : public Resource {
   VkImage GetVkImage() const { return image_; }
   VkImageView GetVkImageView() const { return view_; }
 
-  // TODO(jaebaek): Implement CopyToDevice
-
   void ChangeLayout(CommandBuffer* command,
                     VkImageLayout old_layout,
                     VkImageLayout new_layout,
@@ -51,7 +49,7 @@ class TransferImage : public Resource {
   // Only record the command for copying this image to its secondary
   // host-accessible buffer. The actual submission of the command
   // must be done later.
-  Result CopyToHost(CommandBuffer* command) override;
+  void CopyToHost(CommandBuffer* command) override;
 
  private:
   Result CreateVkImageView();
diff --git a/src/vulkan/vertex_buffer.cc b/src/vulkan/vertex_buffer.cc
index 36d5b03..2fd8e59 100644
--- a/src/vulkan/vertex_buffer.cc
+++ b/src/vulkan/vertex_buffer.cc
@@ -56,7 +56,8 @@ Result VertexBuffer::FillVertexBufferWithData(CommandBuffer* command) {
     ptr_in_stride_begin += Get4BytesAlignedStride();
   }
 
-  return transfer_buffer_->CopyToDevice(command);
+  transfer_buffer_->CopyToDevice(command);
+  return {};
 }
 
 void VertexBuffer::BindToCommandBuffer(CommandBuffer* command) {
diff --git a/src/vulkan/vertex_buffer_test.cc b/src/vulkan/vertex_buffer_test.cc
index e02f53c..eaedd67 100644
--- a/src/vulkan/vertex_buffer_test.cc
+++ b/src/vulkan/vertex_buffer_test.cc
@@ -40,7 +40,7 @@ class BufferForTest : public TransferBuffer {
   }
   ~BufferForTest() override = default;
 
-  Result CopyToDevice(CommandBuffer*) override { return Result(); }
+  void CopyToDevice(CommandBuffer*) override {}
 
  private:
   std::vector<uint8_t> memory_;