ui: Add Linux dma-buf implementation of GLImage.

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;
+  }
+}
+
+}  // namespace
+
+GLImageLinuxDMABuffer::GLImageLinuxDMABuffer(gfx::Size size,
+                                             unsigned internalformat)
+    : GLImageEGL(size), internalformat_(internalformat), fd_(-1) {}
+
+GLImageLinuxDMABuffer::~GLImageLinuxDMABuffer() { Destroy(); }
+
+bool GLImageLinuxDMABuffer::Initialize(gfx::GpuMemoryBufferHandle buffer) {
+  if (!ValidFormat(internalformat_)) {
+    LOG(ERROR) << "Invalid format: " << internalformat_;
+    return false;
+  }
+
+  if (buffer.handle.fd < 0) {
+    LOG(ERROR) << "Invalid file descriptor: " << buffer.handle.fd;
+    return false;
+  }
+
+  fd_ = dup(buffer.handle.fd);
+  if (fd_ < 0) {
+    LOG(ERROR) << "Failed to duplicate file descriptor.";
+    return false;
+  }
+
+  EGLint attrs[] = {EGL_WIDTH,
+                    size_.width(),
+                    EGL_HEIGHT,
+                    size_.height(),
+                    EGL_LINUX_DRM_FOURCC_EXT,
+                    FourCC(internalformat_),
+                    EGL_DMA_BUF_PLANE0_FD_EXT,
+                    fd_,
+                    EGL_DMA_BUF_PLANE0_OFFSET_EXT,
+                    0,
+                    EGL_DMA_BUF_PLANE0_PITCH_EXT,
+                    size_.width() * BytesPerPixel(internalformat_),
+                    EGL_NONE};
+  return GLImageEGL::Initialize(
+      EGL_LINUX_DMA_BUF_EXT, static_cast<EGLClientBuffer>(NULL), attrs);
+}
+
+void GLImageLinuxDMABuffer::Destroy() {
+  GLImageEGL::Destroy();
+  if (fd_ >= 0)
+    close(fd_);

[fjhenigman, 2014/03/27 23:35:49]

The spec [1] and a mesa-dev thread [2] and the current mesa implementation
suggest to me that we don't need to keep the file descriptor open after
Initialize().  A piglit test seems to disagree but it may be out of date.
If so, we can do away with the dup() and close().  I wouldn't bet my life on it
but I would give it a try.

[1]
https://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_imp...
: "If eglCreateImageKHR is successful for a EGL_LINUX_DMA_BUF_EXT target, the
EGL will take a reference to the dma_buf(s) which it will release at any time
while the EGLDisplay is initialized.  It is the responsibility of the
application to close the dma_buf file descriptors."

[2] http://marc.info/?t=138153116700005

[reveman, 2014/03/27 23:57:14]

Ok, cool. Removed dup from latest patch.

+}
+
+}  // namespace gfx