[WIP] Not for review. Zero copy.

ui/gl/gl_image_linux_dma_buffer.cc

+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/gl/gl_image_linux_dma_buffer.h"
+
+#include <unistd.h>
+
+#define FOURCC(a, b, c, d)                                    \
+  ((static_cast<uint32>(a)) | (static_cast<uint32>(b) << 8) | \
+   (static_cast<uint32>(c) << 16) | (static_cast<uint32>(d) << 24))
+
+#define DRM_FORMAT_ARGB8888 FOURCC('A', 'R', '2', '4')
+
+namespace gfx {
+namespace {
+
+bool ValidFormat(unsigned internalformat) {
+  switch (internalformat) {
+    case GL_BGRA8_EXT:
+      return true;
+    default:
+      return false;
+  }
+}
+
+EGLint FourCC(unsigned internalformat) {
+  switch (internalformat) {
+    case GL_BGRA8_EXT:
+      return DRM_FORMAT_ARGB8888;
+    default:
+      NOTREACHED();
+      return 0;
+  }
+}
+
+int BytesPerPixel(unsigned internalformat) {
+  switch (internalformat) {
+    case GL_BGRA8_EXT:
+      return 4;
+    default:
+      NOTREACHED();
+      return 0;
+  }
+}
+
+bool IsHandleValid(const base::FileDescriptor& handle) {
+  return handle.fd >= 0;
+}
+
+// Aligns 'value' by rounding it up to the next multiple of 'alignment'
+int AlignValue(int value, int alignment) {
+  return value + (alignment - (value % alignment)) % alignment;
+}
+
+}  // namespace
+
+GLImageLinuxDMABuffer::GLImageLinuxDMABuffer(gfx::Size size,
+                                             unsigned internalformat)
+    : GLImageEGL(size), internalformat_(internalformat) {}
+
+GLImageLinuxDMABuffer::~GLImageLinuxDMABuffer() { Destroy(); }
+
+bool GLImageLinuxDMABuffer::Initialize(gfx::GpuMemoryBufferHandle buffer) {
+  if (!ValidFormat(internalformat_)) {
+    LOG(ERROR) << "Invalid format: " << internalformat_;
+    return false;
+  }
+
+  if (!IsHandleValid(buffer.handle)) {
+    LOG(ERROR) << "Invalid file descriptor: " << buffer.handle.fd;
+    return false;
+  }
+
+  // Align stride to a multiple of 64.
+  int stride = AlignValue(size_.width() * BytesPerPixel(internalformat_), 64);
+
+  // Note: If eglCreateImageKHR is successful for a EGL_LINUX_DMA_BUF_EXT
+  // target, the EGL will take a reference to the dma_buf.
+  EGLint attrs[] = {EGL_WIDTH,                     size_.width(),
+                    EGL_HEIGHT,                    size_.height(),
+                    EGL_LINUX_DRM_FOURCC_EXT,      FourCC(internalformat_),
+                    EGL_DMA_BUF_PLANE0_FD_EXT,     buffer.handle.fd,
+                    EGL_DMA_BUF_PLANE0_OFFSET_EXT, 0,
+                    EGL_DMA_BUF_PLANE0_PITCH_EXT,  stride,
+                    EGL_NONE};
+  return GLImageEGL::Initialize(
+      EGL_LINUX_DMA_BUF_EXT, static_cast<EGLClientBuffer>(NULL), attrs);
+}
+
+}  // namespace gfx