// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gfx/gpu_fence.h"

#include "base/logging.h"
#include "base/notreached.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "build/chromeos_buildflags.h"

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)
#include <sync/sync.h>
#endif

namespace gfx {

GpuFence::GpuFence(GpuFenceHandle fence_handle)
    : fence_handle_(std::move(fence_handle)) {}

GpuFence::~GpuFence() = default;

GpuFence::GpuFence(GpuFence&& other) = default;

GpuFence& GpuFence::operator=(GpuFence&& other) = default;

const GpuFenceHandle& GpuFence::GetGpuFenceHandle() const {
  return fence_handle_;
}

ClientGpuFence GpuFence::AsClientGpuFence() {
  return reinterpret_cast<ClientGpuFence>(this);
}

// static
GpuFence* GpuFence::FromClientGpuFence(ClientGpuFence gpu_fence) {
  return reinterpret_cast<GpuFence*>(gpu_fence);
}

void GpuFence::Wait() {
  if (fence_handle_.is_null()) {
    return;
  }

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)
  static const int kInfiniteSyncWaitTimeout = -1;
  DCHECK_GE(fence_handle_.Peek(), 0);
  if (sync_wait(fence_handle_.Peek(), kInfiniteSyncWaitTimeout) < 0) {
    LOG(FATAL) << "Failed while waiting for gpu fence fd";
  }
#else
  NOTREACHED();
#endif
}

// static
GpuFence::FenceStatus GpuFence::GetStatusChangeTime(int fd,
                                                    base::TimeTicks* time) {
  DCHECK_NE(fd, -1);
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_CHROMEOS)
#if BUILDFLAG(IS_CHROMEOS_DEVICE)
  auto info =
      std::unique_ptr<sync_fence_info_data, void (*)(sync_fence_info_data*)>{
          sync_fence_info(fd), sync_fence_info_free};
#else   // !BUILDFLAG(IS_CHROMEOS_DEVICE)
  auto info =
      std::unique_ptr<struct sync_file_info, void (*)(struct sync_file_info*)>{
          sync_file_info(fd), sync_file_info_free};
#endif  // BUILDFLAG(IS_CHROMEOS_DEVICE)
  if (!info) {
    LOG(ERROR) << "sync_(file|fence)_info returned null for fd : " << fd;
    return FenceStatus::kInvalid;
  }

  if (info->status < 0) {
    LOG(ERROR) << "sync_(file|fence)_info status error for fd : " << fd;
    return FenceStatus::kInvalid;
  }

  // Not signalled yet.
  if (info->status != 1) {
    return FenceStatus::kNotSignaled;
  }

  uint64_t timestamp_ns = 0u;
#if BUILDFLAG(IS_CHROMEOS_DEVICE)
  struct sync_pt_info* pt_info = nullptr;
  while ((pt_info = sync_pt_info(info.get(), pt_info))) {
    timestamp_ns = std::max(timestamp_ns, pt_info->timestamp_ns);
  }
#else   // !BUILDFLAG(IS_CHROMEOS_DEVICE)
  struct sync_fence_info* f_infos = sync_get_fence_info(info.get());
  for (size_t i = 0; i < info->num_fences; i++) {
    // SAFETY: Linux kernel guarantees size of sync_get_fence_info() is the same
    // as sync_file_info->num_fences.
    auto& f_info = UNSAFE_BUFFERS(f_infos[i]);
    timestamp_ns =
        std::max(timestamp_ns, static_cast<uint64_t>(f_info.timestamp_ns));
  }
#endif  // BUILDFLAG(IS_CHROMEOS_DEVICE)

  if (timestamp_ns == 0u) {
    LOG(ERROR) << "No timestamp provided from sync_(pt|fence)_info for fd : "
               << fd;
    return FenceStatus::kInvalid;
  }
  *time = base::TimeTicks() + base::Nanoseconds(timestamp_ns);
  return FenceStatus::kSignaled;
#else
  NOTREACHED();
#endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_ANDROID) ||
        // BUILDFLAG(IS_CHROMEOS)
}

base::TimeTicks GpuFence::GetMaxTimestamp() const {
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)
  base::TimeTicks timestamp;
  FenceStatus status = GetStatusChangeTime(fence_handle_.Peek(), &timestamp);
  DCHECK_EQ(status, FenceStatus::kSignaled);
  return timestamp;
#else
  NOTREACHED();
#endif
}

}  // namespace gfx