#include "include/private/dvr/buffer_hub_queue_client.h"

#include <inttypes.h>
#include <log/log.h>
#include <poll.h>
#include <sys/epoll.h>

#include <array>

#include <pdx/default_transport/client_channel.h>
#include <pdx/default_transport/client_channel_factory.h>
#include <pdx/file_handle.h>
#include <pdx/trace.h>

#define RETRY_EINTR(fnc_call)                 \
  ([&]() -> decltype(fnc_call) {              \
    decltype(fnc_call) result;                \
    do {                                      \
      result = (fnc_call);                    \
    } while (result == -1 && errno == EINTR); \
    return result;                            \
  })()

using android::pdx::ErrorStatus;
using android::pdx::LocalChannelHandle;
using android::pdx::LocalHandle;
using android::pdx::Status;

namespace android {
namespace dvr {

namespace {

std::pair<int32_t, int32_t> Unstuff(uint64_t value) {
  return {static_cast<int32_t>(value >> 32),
          static_cast<int32_t>(value & ((1ull << 32) - 1))};
}

uint64_t Stuff(int32_t a, int32_t b) {
  const uint32_t ua = static_cast<uint32_t>(a);
  const uint32_t ub = static_cast<uint32_t>(b);
  return (static_cast<uint64_t>(ua) << 32) | static_cast<uint64_t>(ub);
}

}  // anonymous namespace

BufferHubQueue::BufferHubQueue(LocalChannelHandle channel_handle)
    : Client{pdx::default_transport::ClientChannel::Create(
          std::move(channel_handle))} {
  Initialize();
}

BufferHubQueue::BufferHubQueue(const std::string& endpoint_path)
    : Client{
          pdx::default_transport::ClientChannelFactory::Create(endpoint_path)} {
  Initialize();
}

void BufferHubQueue::Initialize() {
  int ret = epoll_fd_.Create();
  if (ret < 0) {
    ALOGE("BufferHubQueue::BufferHubQueue: Failed to create epoll fd: %s",
          strerror(-ret));
    return;
  }

  epoll_event event = {
      .events = EPOLLIN | EPOLLET,
      .data = {.u64 = Stuff(-1, BufferHubQueue::kEpollQueueEventIndex)}};
  ret = epoll_fd_.Control(EPOLL_CTL_ADD, event_fd(), &event);
  if (ret < 0) {
    ALOGE("%s: Failed to add event fd to epoll set: %s", __FUNCTION__,
          strerror(-ret));
  }
}

Status<void> BufferHubQueue::ImportQueue() {
  auto status = InvokeRemoteMethod<BufferHubRPC::GetQueueInfo>();
  if (!status) {
    ALOGE("%s: Failed to import queue: %s", __FUNCTION__,
          status.GetErrorMessage().c_str());
    return ErrorStatus(status.error());
  } else {
    SetupQueue(status.get());
    return {};
  }
}

void BufferHubQueue::SetupQueue(const QueueInfo& queue_info) {
  is_async_ = queue_info.producer_config.is_async;
  default_width_ = queue_info.producer_config.default_width;
  default_height_ = queue_info.producer_config.default_height;
  default_format_ = queue_info.producer_config.default_format;
  user_metadata_size_ = queue_info.producer_config.user_metadata_size;
  id_ = queue_info.id;
}

std::unique_ptr<ConsumerQueue> BufferHubQueue::CreateConsumerQueue() {
  if (auto status = CreateConsumerQueueHandle(/*silent*/ false))
    return std::unique_ptr<ConsumerQueue>(new ConsumerQueue(status.take()));
  else
    return nullptr;
}

std::unique_ptr<ConsumerQueue> BufferHubQueue::CreateSilentConsumerQueue() {
  if (auto status = CreateConsumerQueueHandle(/*silent*/ true))
    return std::unique_ptr<ConsumerQueue>(new ConsumerQueue(status.take()));
  else
    return nullptr;
}

Status<LocalChannelHandle> BufferHubQueue::CreateConsumerQueueHandle(
    bool silent) {
  auto status = InvokeRemoteMethod<BufferHubRPC::CreateConsumerQueue>(silent);
  if (!status) {
    ALOGE(
        "BufferHubQueue::CreateConsumerQueue: Failed to create consumer queue: "
        "%s",
        status.GetErrorMessage().c_str());
    return ErrorStatus(status.error());
  }

  return status;
}

pdx::Status<ConsumerQueueParcelable>
BufferHubQueue::CreateConsumerQueueParcelable(bool silent) {
  auto status = CreateConsumerQueueHandle(silent);
  if (!status)
    return status.error_status();

  // A temporary consumer queue client to pull its channel parcelable.
  auto consumer_queue =
      std::unique_ptr<ConsumerQueue>(new ConsumerQueue(status.take()));
  ConsumerQueueParcelable queue_parcelable(
      consumer_queue->GetChannel()->TakeChannelParcelable());

  if (!queue_parcelable.IsValid()) {
    ALOGE("%s: Failed to create consumer queue parcelable.", __FUNCTION__);
    return ErrorStatus(EINVAL);
  }

  return {std::move(queue_parcelable)};
}

bool BufferHubQueue::WaitForBuffers(int timeout) {
  ATRACE_NAME("BufferHubQueue::WaitForBuffers");
  std::array<epoll_event, kMaxEvents> events;

  // Loop at least once to check for hangups.
  do {
    ALOGD_IF(
        TRACE,
        "BufferHubQueue::WaitForBuffers: queue_id=%d count=%zu capacity=%zu",
        id(), count(), capacity());

    // If there is already a buffer then just check for hangup without waiting.
    const int ret = epoll_fd_.Wait(events.data(), events.size(),
                                   count() == 0 ? timeout : 0);

    if (ret == 0) {
      ALOGI_IF(TRACE,
               "BufferHubQueue::WaitForBuffers: No events before timeout: "
               "queue_id=%d",
               id());
      return count() != 0;
    }

    if (ret < 0 && ret != -EINTR) {
      ALOGE("%s: Failed to wait for buffers: %s", __FUNCTION__, strerror(-ret));
      return false;
    }

    const int num_events = ret;

    // A BufferQueue's epoll fd tracks N+1 events, where there are N events,
    // one for each buffer in the queue, and one extra event for the queue
    // client itself.
    for (int i = 0; i < num_events; i++) {
      int32_t event_fd;
      int32_t index;
      std::tie(event_fd, index) = Unstuff(events[i].data.u64);

      PDX_TRACE_FORMAT(
          "epoll_event|queue_id=%d;num_events=%d;event_index=%d;event_fd=%d;"
          "slot=%d|",
          id(), num_events, i, event_fd, index);

      ALOGD_IF(TRACE,
               "BufferHubQueue::WaitForBuffers: event %d: event_fd=%d index=%d",
               i, event_fd, index);

      if (is_buffer_event_index(index)) {
        HandleBufferEvent(static_cast<size_t>(index), event_fd,
                          events[i].events);
      } else if (is_queue_event_index(index)) {
        HandleQueueEvent(events[i].events);
      } else {
        ALOGW(
            "BufferHubQueue::WaitForBuffers: Unknown event type event_fd=%d "
            "index=%d",
            event_fd, index);
      }
    }
  } while (count() == 0 && capacity() > 0 && !hung_up());

  return count() != 0;
}

Status<void> BufferHubQueue::HandleBufferEvent(size_t slot, int event_fd,
                                               int poll_events) {
  ATRACE_NAME("BufferHubQueue::HandleBufferEvent");
  if (!buffers_[slot]) {
    ALOGW("BufferHubQueue::HandleBufferEvent: Invalid buffer slot: %zu", slot);
    return ErrorStatus(ENOENT);
  }

  auto status = buffers_[slot]->GetEventMask(poll_events);
  if (!status) {
    ALOGW("BufferHubQueue::HandleBufferEvent: Failed to get event mask: %s",
          status.GetErrorMessage().c_str());
    return status.error_status();
  }

  const int events = status.get();
  PDX_TRACE_FORMAT(
      "buffer|queue_id=%d;buffer_id=%d;slot=%zu;event_fd=%d;poll_events=%x;"
      "events=%d|",
      id(), buffers_[slot]->id(), slot, event_fd, poll_events, events);

  if (events & EPOLLIN) {
    return Enqueue({buffers_[slot], slot, buffers_[slot]->GetQueueIndex()});
  } else if (events & EPOLLHUP) {
    ALOGW(
        "BufferHubQueue::HandleBufferEvent: Received EPOLLHUP event: slot=%zu "
        "event_fd=%d buffer_id=%d",
        slot, buffers_[slot]->event_fd(), buffers_[slot]->id());
    return RemoveBuffer(slot);
  } else {
    ALOGW(
        "BufferHubQueue::HandleBufferEvent: Unknown event, slot=%zu, epoll "
        "events=%d",
        slot, events);
  }

  return {};
}

Status<void> BufferHubQueue::HandleQueueEvent(int poll_event) {
  ATRACE_NAME("BufferHubQueue::HandleQueueEvent");
  auto status = GetEventMask(poll_event);
  if (!status) {
    ALOGW("BufferHubQueue::HandleQueueEvent: Failed to get event mask: %s",
          status.GetErrorMessage().c_str());
    return status.error_status();
  }

  const int events = status.get();
  if (events & EPOLLIN) {
    // Note that after buffer imports, if |count()| still returns 0, epoll
    // wait will be tried again to acquire the newly imported buffer.
    auto buffer_status = OnBufferAllocated();
    if (!buffer_status) {
      ALOGE("%s: Failed to import buffer: %s", __FUNCTION__,
            buffer_status.GetErrorMessage().c_str());
    }
  } else if (events & EPOLLHUP) {
    ALOGD_IF(TRACE, "%s: hang up event!", __FUNCTION__);
    hung_up_ = true;
  } else {
    ALOGW("%s: Unknown epoll events=%x", __FUNCTION__, events);
  }

  return {};
}

Status<void> BufferHubQueue::AddBuffer(
    const std::shared_ptr<BufferHubBase>& buffer, size_t slot) {
  ALOGD_IF(TRACE, "%s: buffer_id=%d slot=%zu", __FUNCTION__, buffer->id(),
           slot);

  if (is_full()) {
    ALOGE("%s: queue is at maximum capacity: %zu", __FUNCTION__, capacity_);
    return ErrorStatus(E2BIG);
  }

  if (buffers_[slot]) {
    // Replace the buffer if the slot is occupied. This could happen when the
    // producer side replaced the slot with a newly allocated buffer. Remove the
    // buffer before setting up with the new one.
    auto remove_status = RemoveBuffer(slot);
    if (!remove_status)
      return remove_status.error_status();
  }

  for (const auto& event_source : buffer->GetEventSources()) {
    epoll_event event = {.events = event_source.event_mask | EPOLLET,
                         .data = {.u64 = Stuff(buffer->event_fd(), slot)}};
    const int ret =
        epoll_fd_.Control(EPOLL_CTL_ADD, event_source.event_fd, &event);
    if (ret < 0) {
      ALOGE("%s: Failed to add buffer to epoll set: %s", __FUNCTION__,
            strerror(-ret));
      return ErrorStatus(-ret);
    }
  }

  buffers_[slot] = buffer;
  capacity_++;
  return {};
}

Status<void> BufferHubQueue::RemoveBuffer(size_t slot) {
  ALOGD_IF(TRACE, "%s: slot=%zu", __FUNCTION__, slot);

  if (buffers_[slot]) {
    for (const auto& event_source : buffers_[slot]->GetEventSources()) {
      const int ret =
          epoll_fd_.Control(EPOLL_CTL_DEL, event_source.event_fd, nullptr);
      if (ret < 0) {
        ALOGE("%s: Failed to remove buffer from epoll set: %s", __FUNCTION__,
              strerror(-ret));
        return ErrorStatus(-ret);
      }
    }

    // Trigger OnBufferRemoved callback if registered.
    if (on_buffer_removed_)
      on_buffer_removed_(buffers_[slot]);

    buffers_[slot] = nullptr;
    capacity_--;
  }

  return {};
}

Status<void> BufferHubQueue::Enqueue(Entry entry) {
  if (!is_full()) {
    // Find and remove the enqueued buffer from unavailable_buffers_slot if
    // exist.
    auto enqueued_buffer_iter = std::find_if(
        unavailable_buffers_slot_.begin(), unavailable_buffers_slot_.end(),
        [&entry](size_t slot) -> bool { return slot == entry.slot; });
    if (enqueued_buffer_iter != unavailable_buffers_slot_.end()) {
      unavailable_buffers_slot_.erase(enqueued_buffer_iter);
    }

    available_buffers_.push(std::move(entry));

    // Trigger OnBufferAvailable callback if registered.
    if (on_buffer_available_)
      on_buffer_available_();

    return {};
  } else {
    ALOGE("%s: Buffer queue is full!", __FUNCTION__);
    return ErrorStatus(E2BIG);
  }
}

Status<std::shared_ptr<BufferHubBase>> BufferHubQueue::Dequeue(int timeout,
                                                               size_t* slot) {
  ALOGD_IF(TRACE, "%s: count=%zu, timeout=%d", __FUNCTION__, count(), timeout);

  PDX_TRACE_FORMAT("%s|count=%zu|", __FUNCTION__, count());

  if (count() == 0) {
    if (!WaitForBuffers(timeout))
      return ErrorStatus(ETIMEDOUT);
  }

  auto& entry = available_buffers_.top();
  PDX_TRACE_FORMAT("buffer|buffer_id=%d;slot=%zu|", entry.buffer->id(),
                   entry.slot);

  std::shared_ptr<BufferHubBase> buffer = std::move(entry.buffer);
  *slot = entry.slot;

  available_buffers_.pop();
  unavailable_buffers_slot_.push_back(*slot);

  return {std::move(buffer)};
}

void BufferHubQueue::SetBufferAvailableCallback(
    BufferAvailableCallback callback) {
  on_buffer_available_ = callback;
}

void BufferHubQueue::SetBufferRemovedCallback(BufferRemovedCallback callback) {
  on_buffer_removed_ = callback;
}

pdx::Status<void> BufferHubQueue::FreeAllBuffers() {
  // Clear all available buffers.
  while (!available_buffers_.empty())
    available_buffers_.pop();

  pdx::Status<void> last_error;  // No error.
  // Clear all buffers this producer queue is tracking.
  for (size_t slot = 0; slot < BufferHubQueue::kMaxQueueCapacity; slot++) {
    if (buffers_[slot] != nullptr) {
      auto status = RemoveBuffer(slot);
      if (!status) {
        ALOGE(
            "ProducerQueue::FreeAllBuffers: Failed to remove buffer at "
            "slot=%zu.",
            slot);
        last_error = status.error_status();
      }
    }
  }

  return last_error;
}

ProducerQueue::ProducerQueue(LocalChannelHandle handle)
    : BASE(std::move(handle)) {
  auto status = ImportQueue();
  if (!status) {
    ALOGE("ProducerQueue::ProducerQueue: Failed to import queue: %s",
          status.GetErrorMessage().c_str());
    Close(-status.error());
  }
}

ProducerQueue::ProducerQueue(const ProducerQueueConfig& config,
                             const UsagePolicy& usage)
    : BASE(BufferHubRPC::kClientPath) {
  auto status =
      InvokeRemoteMethod<BufferHubRPC::CreateProducerQueue>(config, usage);
  if (!status) {
    ALOGE("ProducerQueue::ProducerQueue: Failed to create producer queue: %s",
          status.GetErrorMessage().c_str());
    Close(-status.error());
    return;
  }

  SetupQueue(status.get());
}

Status<std::vector<size_t>> ProducerQueue::AllocateBuffers(
    uint32_t width, uint32_t height, uint32_t layer_count, uint32_t format,
    uint64_t usage, size_t buffer_count) {
  if (buffer_count == 0) {
    return {std::vector<size_t>()};
  }

  if (capacity() + buffer_count > kMaxQueueCapacity) {
    ALOGE(
        "ProducerQueue::AllocateBuffers: queue is at capacity: %zu, cannot "
        "allocate %zu more buffer(s).",
        capacity(), buffer_count);
    return ErrorStatus(E2BIG);
  }

  Status<std::vector<std::pair<LocalChannelHandle, size_t>>> status =
      InvokeRemoteMethod<BufferHubRPC::ProducerQueueAllocateBuffers>(
          width, height, layer_count, format, usage, buffer_count);
  if (!status) {
    ALOGE("ProducerQueue::AllocateBuffers: failed to allocate buffers: %s",
          status.GetErrorMessage().c_str());
    return status.error_status();
  }

  auto buffer_handle_slots = status.take();
  LOG_ALWAYS_FATAL_IF(buffer_handle_slots.size() != buffer_count,
                      "BufferHubRPC::ProducerQueueAllocateBuffers should "
                      "return %zu buffer handle(s), but returned %zu instead.",
                      buffer_count, buffer_handle_slots.size());

  std::vector<size_t> buffer_slots;
  buffer_slots.reserve(buffer_count);

  // Bookkeeping for each buffer.
  for (auto& hs : buffer_handle_slots) {
    auto& buffer_handle = hs.first;
    size_t buffer_slot = hs.second;

    // Note that import might (though very unlikely) fail. If so, buffer_handle
    // will be closed and included in returned buffer_slots.
    if (AddBuffer(ProducerBuffer::Import(std::move(buffer_handle)),
                  buffer_slot)) {
      ALOGD_IF(TRACE, "ProducerQueue::AllocateBuffers: new buffer at slot: %zu",
               buffer_slot);
      buffer_slots.push_back(buffer_slot);
    }
  }

  if (buffer_slots.size() != buffer_count) {
    // Error out if the count of imported buffer(s) is not correct.
    ALOGE(
        "ProducerQueue::AllocateBuffers: requested to import %zu "
        "buffers, but actually imported %zu buffers.",
        buffer_count, buffer_slots.size());
    return ErrorStatus(ENOMEM);
  }

  return {std::move(buffer_slots)};
}

Status<size_t> ProducerQueue::AllocateBuffer(uint32_t width, uint32_t height,
                                             uint32_t layer_count,
                                             uint32_t format, uint64_t usage) {
  // We only allocate one buffer at a time.
  constexpr size_t buffer_count = 1;
  auto status =
      AllocateBuffers(width, height, layer_count, format, usage, buffer_count);
  if (!status) {
    ALOGE("ProducerQueue::AllocateBuffer: Failed to allocate buffer: %s",
          status.GetErrorMessage().c_str());
    return status.error_status();
  }

  return {status.get()[0]};
}

Status<void> ProducerQueue::AddBuffer(
    const std::shared_ptr<ProducerBuffer>& buffer, size_t slot) {
  ALOGD_IF(TRACE, "ProducerQueue::AddBuffer: queue_id=%d buffer_id=%d slot=%zu",
           id(), buffer->id(), slot);
  // For producer buffer, we need to enqueue the newly added buffer
  // immediately. Producer queue starts with all buffers in available state.
  auto status = BufferHubQueue::AddBuffer(buffer, slot);
  if (!status)
    return status;

  return BufferHubQueue::Enqueue({buffer, slot, 0ULL});
}

Status<size_t> ProducerQueue::InsertBuffer(
    const std::shared_ptr<ProducerBuffer>& buffer) {
  if (buffer == nullptr ||
      !BufferHubDefs::isClientGained(buffer->buffer_state(),
                                     buffer->client_state_mask())) {
    ALOGE(
        "ProducerQueue::InsertBuffer: Can only insert a buffer when it's in "
        "gained state.");
    return ErrorStatus(EINVAL);
  }

  auto status_or_slot =
      InvokeRemoteMethod<BufferHubRPC::ProducerQueueInsertBuffer>(
          buffer->cid());
  if (!status_or_slot) {
    ALOGE(
        "ProducerQueue::InsertBuffer: Failed to insert producer buffer: "
        "buffer_cid=%d, error: %s.",
        buffer->cid(), status_or_slot.GetErrorMessage().c_str());
    return status_or_slot.error_status();
  }

  size_t slot = status_or_slot.get();

  // Note that we are calling AddBuffer() from the base class to explicitly
  // avoid Enqueue() the ProducerBuffer.
  auto status = BufferHubQueue::AddBuffer(buffer, slot);
  if (!status) {
    ALOGE("ProducerQueue::InsertBuffer: Failed to add buffer: %s.",
          status.GetErrorMessage().c_str());
    return status.error_status();
  }
  return {slot};
}

Status<void> ProducerQueue::RemoveBuffer(size_t slot) {
  auto status =
      InvokeRemoteMethod<BufferHubRPC::ProducerQueueRemoveBuffer>(slot);
  if (!status) {
    ALOGE("%s: Failed to remove producer buffer: %s", __FUNCTION__,
          status.GetErrorMessage().c_str());
    return status.error_status();
  }

  return BufferHubQueue::RemoveBuffer(slot);
}

Status<std::shared_ptr<ProducerBuffer>> ProducerQueue::Dequeue(
    int timeout, size_t* slot, LocalHandle* release_fence) {
  DvrNativeBufferMetadata canonical_meta;
  return Dequeue(timeout, slot, &canonical_meta, release_fence);
}

pdx::Status<std::shared_ptr<ProducerBuffer>> ProducerQueue::Dequeue(
    int timeout, size_t* slot, DvrNativeBufferMetadata* out_meta,
    pdx::LocalHandle* release_fence, bool gain_posted_buffer) {
  ATRACE_NAME("ProducerQueue::Dequeue");
  if (slot == nullptr || out_meta == nullptr || release_fence == nullptr) {
    ALOGE("%s: Invalid parameter.", __FUNCTION__);
    return ErrorStatus(EINVAL);
  }

  std::shared_ptr<ProducerBuffer> buffer;
  Status<std::shared_ptr<BufferHubBase>> dequeue_status =
      BufferHubQueue::Dequeue(timeout, slot);
  if (dequeue_status.ok()) {
    buffer = std::static_pointer_cast<ProducerBuffer>(dequeue_status.take());
  } else {
    if (gain_posted_buffer) {
      Status<std::shared_ptr<ProducerBuffer>> dequeue_unacquired_status =
          ProducerQueue::DequeueUnacquiredBuffer(slot);
      if (!dequeue_unacquired_status.ok()) {
        ALOGE("%s: DequeueUnacquiredBuffer returned error: %d", __FUNCTION__,
              dequeue_unacquired_status.error());
        return dequeue_unacquired_status.error_status();
      }
      buffer = dequeue_unacquired_status.take();
    } else {
      return dequeue_status.error_status();
    }
  }
  const int ret =
      buffer->GainAsync(out_meta, release_fence, gain_posted_buffer);
  if (ret < 0 && ret != -EALREADY)
    return ErrorStatus(-ret);

  return {std::move(buffer)};
}

Status<std::shared_ptr<ProducerBuffer>> ProducerQueue::DequeueUnacquiredBuffer(
    size_t* slot) {
  if (unavailable_buffers_slot_.size() < 1) {
    ALOGE(
        "%s: Failed to dequeue un-acquired buffer. All buffer(s) are in "
        "acquired state if exist.",
        __FUNCTION__);
    return ErrorStatus(ENOMEM);
  }

  // Find the first buffer that is not in acquired state from
  // unavailable_buffers_slot_.
  for (auto iter = unavailable_buffers_slot_.begin();
       iter != unavailable_buffers_slot_.end(); iter++) {
    std::shared_ptr<ProducerBuffer> buffer = ProducerQueue::GetBuffer(*iter);
    if (buffer == nullptr) {
      ALOGE("%s failed. Buffer slot %d is  null.", __FUNCTION__,
            static_cast<int>(*slot));
      return ErrorStatus(EIO);
    }
    if (!BufferHubDefs::isAnyClientAcquired(buffer->buffer_state())) {
      *slot = *iter;
      unavailable_buffers_slot_.erase(iter);
      unavailable_buffers_slot_.push_back(*slot);
      ALOGD("%s: Producer queue dequeue unacquired buffer in slot %d",
            __FUNCTION__, static_cast<int>(*slot));
      return {std::move(buffer)};
    }
  }
  ALOGE(
      "%s: Failed to dequeue un-acquired buffer. No un-acquired buffer exist.",
      __FUNCTION__);
  return ErrorStatus(EBUSY);
}

pdx::Status<ProducerQueueParcelable> ProducerQueue::TakeAsParcelable() {
  if (capacity() != 0) {
    ALOGE(
        "%s: producer queue can only be taken out as a parcelable when empty. "
        "Current queue capacity: %zu",
        __FUNCTION__, capacity());
    return ErrorStatus(EINVAL);
  }

  std::unique_ptr<pdx::ClientChannel> channel = TakeChannel();
  ProducerQueueParcelable queue_parcelable(channel->TakeChannelParcelable());

  // Here the queue parcelable is returned and holds the underlying system
  // resources backing the queue; while the original client channel of this
  // producer queue is destroyed in place so that this client can no longer
  // provide producer operations.
  return {std::move(queue_parcelable)};
}

/*static */
std::unique_ptr<ConsumerQueue> ConsumerQueue::Import(
    LocalChannelHandle handle) {
  return std::unique_ptr<ConsumerQueue>(new ConsumerQueue(std::move(handle)));
}

ConsumerQueue::ConsumerQueue(LocalChannelHandle handle)
    : BufferHubQueue(std::move(handle)) {
  auto status = ImportQueue();
  if (!status) {
    ALOGE("%s: Failed to import queue: %s", __FUNCTION__,
          status.GetErrorMessage().c_str());
    Close(-status.error());
  }

  auto import_status = ImportBuffers();
  if (import_status) {
    ALOGI("%s: Imported %zu buffers.", __FUNCTION__, import_status.get());
  } else {
    ALOGE("%s: Failed to import buffers: %s", __FUNCTION__,
          import_status.GetErrorMessage().c_str());
  }
}

Status<size_t> ConsumerQueue::ImportBuffers() {
  auto status = InvokeRemoteMethod<BufferHubRPC::ConsumerQueueImportBuffers>();
  if (!status) {
    if (status.error() == EBADR) {
      ALOGI("%s: Queue is silent, no buffers imported.", __FUNCTION__);
      return {0};
    } else {
      ALOGE("%s: Failed to import consumer buffer: %s", __FUNCTION__,
            status.GetErrorMessage().c_str());
      return status.error_status();
    }
  }

  int ret;
  Status<void> last_error;
  size_t imported_buffers_count = 0;

  auto buffer_handle_slots = status.take();
  for (auto& buffer_handle_slot : buffer_handle_slots) {
    ALOGD_IF(TRACE, ": buffer_handle=%d", __FUNCTION__,
             buffer_handle_slot.first.value());

    std::unique_ptr<ConsumerBuffer> consumer_buffer =
        ConsumerBuffer::Import(std::move(buffer_handle_slot.first));
    if (!consumer_buffer) {
      ALOGE("%s: Failed to import buffer: slot=%zu", __FUNCTION__,
            buffer_handle_slot.second);
      last_error = ErrorStatus(EPIPE);
      continue;
    }

    auto add_status =
        AddBuffer(std::move(consumer_buffer), buffer_handle_slot.second);
    if (!add_status) {
      ALOGE("%s: Failed to add buffer: %s", __FUNCTION__,
            add_status.GetErrorMessage().c_str());
      last_error = add_status;
    } else {
      imported_buffers_count++;
    }
  }

  if (imported_buffers_count > 0)
    return {imported_buffers_count};
  else
    return last_error.error_status();
}

Status<void> ConsumerQueue::AddBuffer(
    const std::shared_ptr<ConsumerBuffer>& buffer, size_t slot) {
  ALOGD_IF(TRACE, "%s: queue_id=%d buffer_id=%d slot=%zu", __FUNCTION__, id(),
           buffer->id(), slot);
  return BufferHubQueue::AddBuffer(buffer, slot);
}

Status<std::shared_ptr<ConsumerBuffer>> ConsumerQueue::Dequeue(
    int timeout, size_t* slot, void* meta, size_t user_metadata_size,
    LocalHandle* acquire_fence) {
  if (user_metadata_size != user_metadata_size_) {
    ALOGE(
        "%s: Metadata size (%zu) for the dequeuing buffer does not match "
        "metadata size (%zu) for the queue.",
        __FUNCTION__, user_metadata_size, user_metadata_size_);
    return ErrorStatus(EINVAL);
  }

  DvrNativeBufferMetadata canonical_meta;
  auto status = Dequeue(timeout, slot, &canonical_meta, acquire_fence);
  if (!status)
    return status.error_status();

  if (meta && user_metadata_size) {
    void* metadata_src =
        reinterpret_cast<void*>(canonical_meta.user_metadata_ptr);
    if (metadata_src) {
      memcpy(meta, metadata_src, user_metadata_size);
    } else {
      ALOGW("%s: no user-defined metadata.", __FUNCTION__);
    }
  }

  return status;
}

Status<std::shared_ptr<ConsumerBuffer>> ConsumerQueue::Dequeue(
    int timeout, size_t* slot, DvrNativeBufferMetadata* out_meta,
    pdx::LocalHandle* acquire_fence) {
  ATRACE_NAME("ConsumerQueue::Dequeue");
  if (slot == nullptr || out_meta == nullptr || acquire_fence == nullptr) {
    ALOGE("%s: Invalid parameter.", __FUNCTION__);
    return ErrorStatus(EINVAL);
  }

  auto status = BufferHubQueue::Dequeue(timeout, slot);
  if (!status)
    return status.error_status();

  auto buffer = std::static_pointer_cast<ConsumerBuffer>(status.take());
  const int ret = buffer->AcquireAsync(out_meta, acquire_fence);
  if (ret < 0)
    return ErrorStatus(-ret);

  return {std::move(buffer)};
}

Status<void> ConsumerQueue::OnBufferAllocated() {
  ALOGD_IF(TRACE, "%s: queue_id=%d", __FUNCTION__, id());

  auto status = ImportBuffers();
  if (!status) {
    ALOGE("%s: Failed to import buffers: %s", __FUNCTION__,
          status.GetErrorMessage().c_str());
    return ErrorStatus(status.error());
  } else if (status.get() == 0) {
    ALOGW("%s: No new buffers allocated!", __FUNCTION__);
    return ErrorStatus(ENOBUFS);
  } else {
    ALOGD_IF(TRACE, "%s: Imported %zu consumer buffers.", __FUNCTION__,
             status.get());
    return {};
  }
}

}  // namespace dvr
}  // namespace android