// Copyright 2019 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 "components/exo/wayland/wl_shm.h"

#include <wayland-server-protocol-core.h>

#include "base/bind.h"
#include "components/exo/buffer.h"
#include "components/exo/display.h"
#include "components/exo/shared_memory.h"
#include "components/exo/wayland/server_util.h"

namespace exo {
namespace wayland {
namespace {

void buffer_destroy(wl_client* client, wl_resource* resource) {
  wl_resource_destroy(resource);
}

const struct wl_buffer_interface buffer_implementation = {buffer_destroy};

void HandleBufferReleaseCallback(wl_resource* resource) {
  wl_buffer_send_release(resource);
  wl_client_flush(wl_resource_get_client(resource));
}

const struct shm_supported_format {
  uint32_t shm_format;
  gfx::BufferFormat buffer_format;
} shm_supported_formats[] = {
    {WL_SHM_FORMAT_XBGR8888, gfx::BufferFormat::RGBX_8888},
    {WL_SHM_FORMAT_ABGR8888, gfx::BufferFormat::RGBA_8888},
    {WL_SHM_FORMAT_XRGB8888, gfx::BufferFormat::BGRX_8888},
    {WL_SHM_FORMAT_ARGB8888, gfx::BufferFormat::BGRA_8888}};

void shm_pool_create_buffer(wl_client* client,
                            wl_resource* resource,
                            uint32_t id,
                            int32_t offset,
                            int32_t width,
                            int32_t height,
                            int32_t stride,
                            uint32_t format) {
  const auto* supported_format =
      std::find_if(shm_supported_formats,
                   shm_supported_formats + base::size(shm_supported_formats),
                   [format](const shm_supported_format& supported_format) {
                     return supported_format.shm_format == format;
                   });
  if (supported_format ==
      (shm_supported_formats + base::size(shm_supported_formats))) {
    wl_resource_post_error(resource, WL_SHM_ERROR_INVALID_FORMAT,
                           "invalid format 0x%x", format);
    return;
  }

  if (offset < 0) {
    wl_resource_post_error(resource, WL_SHM_ERROR_INVALID_FORMAT,
                           "invalid offset %d", offset);
    return;
  }

  std::unique_ptr<Buffer> buffer =
      GetUserDataAs<SharedMemory>(resource)->CreateBuffer(
          gfx::Size(width, height), supported_format->buffer_format, offset,
          stride);
  if (!buffer) {
    wl_resource_post_no_memory(resource);
    return;
  }

  wl_resource* buffer_resource =
      wl_resource_create(client, &wl_buffer_interface, 1, id);

  buffer->set_release_callback(base::BindRepeating(
      &HandleBufferReleaseCallback, base::Unretained(buffer_resource)));

  SetImplementation(buffer_resource, &buffer_implementation, std::move(buffer));
}

void shm_pool_destroy(wl_client* client, wl_resource* resource) {
  wl_resource_destroy(resource);
}

void shm_pool_resize(wl_client* client, wl_resource* resource, int32_t size) {
  auto* shm = GetUserDataAs<SharedMemory>(resource);
  if (size < 0 || static_cast<size_t>(size) < shm->GetSize()) {
    wl_resource_post_error(resource, WL_SHM_ERROR_INVALID_FD,
                           "Can't shrink a shm pool.");
  }

  if (!shm->Resize(size))
    wl_resource_post_no_memory(resource);
}

const struct wl_shm_pool_interface shm_pool_implementation = {
    shm_pool_create_buffer, shm_pool_destroy, shm_pool_resize};

void shm_create_pool(wl_client* client,
                     wl_resource* resource,
                     uint32_t id,
                     int fd,
                     int32_t size) {
  static const auto kMode =
      base::subtle::PlatformSharedMemoryRegion::Mode::kUnsafe;
  auto fd_pair = base::subtle::ScopedFDPair(base::ScopedFD(fd),
                                            base::ScopedFD() /* readonly_fd */);
  auto guid = base::UnguessableToken::Create();
  auto platform_shared_memory = base::subtle::PlatformSharedMemoryRegion::Take(
      std::move(fd_pair), kMode, size, guid);
  std::unique_ptr<SharedMemory> shared_memory =
      GetUserDataAs<Display>(resource)->CreateSharedMemory(
          base::UnsafeSharedMemoryRegion::Deserialize(
              std::move(platform_shared_memory)));
  if (!shared_memory) {
    wl_resource_post_no_memory(resource);
    return;
  }

  wl_resource* shm_pool_resource =
      wl_resource_create(client, &wl_shm_pool_interface, 1, id);

  SetImplementation(shm_pool_resource, &shm_pool_implementation,
                    std::move(shared_memory));
}

const struct wl_shm_interface shm_implementation = {shm_create_pool};

}  // namespace

void bind_shm(wl_client* client, void* data, uint32_t version, uint32_t id) {
  wl_resource* resource = wl_resource_create(client, &wl_shm_interface, 1, id);

  wl_resource_set_implementation(resource, &shm_implementation, data, nullptr);

  for (const auto& supported_format : shm_supported_formats)
    wl_shm_send_format(resource, supported_format.shm_format);
}

}  // namespace wayland
}  // namespace exo