// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gpu/command_buffer/service/shared_image/gl_ozone_image_representation.h"
#include <memory>

#include "base/check.h"
#include "base/memory/scoped_refptr.h"
#include "gpu/command_buffer/service/gl_utils.h"
#include "gpu/command_buffer/service/memory_tracking.h"
#include "gpu/command_buffer/service/shared_image/ozone_image_backing.h"
#include "gpu/command_buffer/service/shared_image/ozone_image_gl_textures_holder.h"
#include "gpu/command_buffer/service/shared_image/shared_image_representation.h"
#include "gpu/command_buffer/service/texture_manager.h"
#include "ui/gl/gl_fence.h"

namespace gpu {

GLTexturePassthroughOzoneImageRepresentation::
    GLTexturePassthroughOzoneImageRepresentation(
        SharedImageManager* manager,
        SharedImageBacking* backing,
        MemoryTypeTracker* tracker,
        scoped_refptr<OzoneImageGLTexturesHolder> textures_holder,
        bool should_mark_context_lost_textures_holder)
    : GLTexturePassthroughImageRepresentation(manager, backing, tracker),
      textures_holder_(std::move(textures_holder)),
      should_mark_context_lost_textures_holder_(
          should_mark_context_lost_textures_holder) {}

GLTexturePassthroughOzoneImageRepresentation::
    ~GLTexturePassthroughOzoneImageRepresentation() {
  if (!has_context()) {
    if (should_mark_context_lost_textures_holder_) {
      textures_holder_->MarkContextLost();
    } else {
      // The textures must have already been marked as context lost given it's
      // only one entry there
      if (textures_holder_->GetCacheCount() <= 1) {
        DCHECK(textures_holder_->WasContextLost());
      }
    }
  }
}

const scoped_refptr<gles2::TexturePassthrough>&
GLTexturePassthroughOzoneImageRepresentation::GetTexturePassthrough(
    size_t plane_index) {
  return textures_holder_->texture(plane_index);
}

bool GLTexturePassthroughOzoneImageRepresentation::BeginAccess(GLenum mode) {
  DCHECK(!current_access_mode_);
  current_access_mode_ = mode;

  auto* ozone_backing = GetOzoneBacking();
  bool readonly = mode != GL_SHARED_IMAGE_ACCESS_MODE_READWRITE_CHROMIUM;
  std::vector<gfx::GpuFenceHandle> fences;
  if (!ozone_backing->BeginAccess(readonly,
                                  OzoneImageBacking::AccessStream::kGL, &fences,
                                  need_end_fence_)) {
    return false;
  }

  // ChromeOS VMs don't support gpu fences, so there is no good way to
  // synchronize with GL.
  if (gl::GLFence::IsGpuFenceSupported()) {
    for (auto& fence : fences) {
      gfx::GpuFence gpu_fence = gfx::GpuFence(std::move(fence));
      std::unique_ptr<gl::GLFence> gl_fence =
          gl::GLFence::CreateFromGpuFence(gpu_fence);
      gl_fence->ServerWait();
    }
  }
  return true;
}

void GLTexturePassthroughOzoneImageRepresentation::EndAccess() {
  gfx::GpuFenceHandle fence;
  // ChromeOS VMs don't support gpu fences, so there is no good way to
  // synchronize with GL.
  if (gl::GLFence::IsGpuFenceSupported() && need_end_fence_) {
    if (auto gl_fence = gl::GLFence::CreateForGpuFence()) {
      auto gpu_fence = gl_fence->GetGpuFence();
      CHECK(gpu_fence);
      fence = gpu_fence->GetGpuFenceHandle().Clone();
    } else {
      DLOG(ERROR) << "Failed to create GPU fence";
    }
  }
  bool readonly =
      current_access_mode_ != GL_SHARED_IMAGE_ACCESS_MODE_READWRITE_CHROMIUM;
  GetOzoneBacking()->EndAccess(readonly, OzoneImageBacking::AccessStream::kGL,
                               std::move(fence));
  current_access_mode_ = 0;
}

OzoneImageBacking*
GLTexturePassthroughOzoneImageRepresentation::GetOzoneBacking() {
  return static_cast<OzoneImageBacking*>(backing());
}

}  // namespace gpu