/*
 * Copyright 2016 The Chromium OS 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 "hal/usb/v4l2_camera_device.h"

#include <fcntl.h>
#include <linux/videodev2.h>
#include <poll.h>
#include <sys/ioctl.h>

#include <algorithm>
#include <limits>

#include <base/files/file_enumerator.h>
#include <base/files/file_util.h>
#include <base/files/scoped_file.h>
#include <base/posix/safe_strerror.h>
#include <base/strings/pattern.h>
#include <base/strings/stringprintf.h>
#include <base/timer/elapsed_timer.h>
#include <camera/camera_metadata.h>
#include <re2/re2.h>

#include "cros-camera/common.h"
#include "cros-camera/utils/camera_config.h"
#include "hal/usb/camera_characteristics.h"
#include "hal/usb/quirks.h"

namespace cros {

namespace {

// Since cameras might report non-integer fps but in Android Camera 3 API we
// can only set fps range with integer in metadata.
constexpr float kFpsDifferenceThreshold = 1.0f;
// The following exposure type strings are from UVC driver.
constexpr char kExposureTypeMenuStringAuto[] = "Auto Mode";
constexpr char kExposureTypeMenuStringManual[] = "Manual Mode";
constexpr char kExposureTypeMenuStringShutterPriority[] =
    "Shutter Priority Mode";
constexpr char kExposureTypeMenuStringAperturePriority[] =
    "Aperture Priority Mode";

const int ControlTypeToCid(ControlType type) {
  switch (type) {
    case kControlAutoWhiteBalance:
      return V4L2_CID_AUTO_WHITE_BALANCE;

    case kControlBrightness:
      return V4L2_CID_BRIGHTNESS;

    case kControlContrast:
      return V4L2_CID_CONTRAST;

    case kControlExposureAuto:
      return V4L2_CID_EXPOSURE_AUTO;

    case kControlExposureAutoPriority:
      return V4L2_CID_EXPOSURE_AUTO_PRIORITY;

    case kControlExposureTime:
      return V4L2_CID_EXPOSURE_ABSOLUTE;

    case kControlFocusAuto:
      return V4L2_CID_FOCUS_AUTO;

    case kControlFocusDistance:
      return V4L2_CID_FOCUS_ABSOLUTE;

    case kControlPan:
      return V4L2_CID_PAN_ABSOLUTE;

    case kControlSaturation:
      return V4L2_CID_SATURATION;

    case kControlSharpness:
      return V4L2_CID_SHARPNESS;

    case kControlTilt:
      return V4L2_CID_TILT_ABSOLUTE;

    case kControlZoom:
      return V4L2_CID_ZOOM_ABSOLUTE;

    case kControlWhiteBalanceTemperature:
      return V4L2_CID_WHITE_BALANCE_TEMPERATURE;

    case kControlPrivacy:
      return V4L2_CID_PRIVACY;

    default:
      NOTREACHED() << "Unexpected control type " << type;
      return -1;
  }
}

const std::string ControlTypeToString(ControlType type) {
  switch (type) {
    case kControlAutoWhiteBalance:
      return "auto white balance";

    case kControlBrightness:
      return "brightness";

    case kControlContrast:
      return "contrast";

    case kControlExposureAuto:
      return "exposure auto (0,3:auto, 1,2:manual)";

    case kControlExposureAutoPriority:
      return "exposure_auto_priority";

    case kControlExposureTime:
      return "exposure time";

    case kControlFocusAuto:
      return "auto focus";

    case kControlFocusDistance:
      return "focus distance";

    case kControlPan:
      return "pan";

    case kControlSaturation:
      return "saturation";

    case kControlSharpness:
      return "sharpness";

    case kControlTilt:
      return "tilt";

    case kControlZoom:
      return "zoom";

    case kControlWhiteBalanceTemperature:
      return "white balance temperature";

    case kControlPrivacy:
      return "privacy";

    default:
      NOTREACHED() << "Unexpected control type " << type;
      return "N/A";
  }
}

const std::string CidToString(int cid) {
  switch (cid) {
    case V4L2_CID_AUTO_WHITE_BALANCE:
      return "V4L2_CID_AUTO_WHITE_BALANCE";

    case V4L2_CID_BRIGHTNESS:
      return "V4L2_CID_BRIGHTNESS";

    case V4L2_CID_CONTRAST:
      return "V4L2_CID_CONTRAST";

    case V4L2_CID_EXPOSURE_ABSOLUTE:
      return "V4L2_CID_EXPOSURE_ABSOLUTE";

    case V4L2_CID_EXPOSURE_AUTO:
      return "V4L2_CID_EXPOSURE_AUTO";

    case V4L2_CID_EXPOSURE_AUTO_PRIORITY:
      return "V4L2_CID_EXPOSURE_AUTO_PRIORITY";

    case V4L2_CID_FOCUS_ABSOLUTE:
      return "V4L2_CID_FOCUS_ABSOLUTE";

    case V4L2_CID_FOCUS_AUTO:
      return "V4L2_CID_FOCUS_AUTO";

    case V4L2_CID_PAN_ABSOLUTE:
      return "V4L2_CID_PAN_ABSOLUTE";

    case V4L2_CID_SATURATION:
      return "V4L2_CID_SATURATION";

    case V4L2_CID_SHARPNESS:
      return "V4L2_CID_SHARPNESS";

    case V4L2_CID_TILT_ABSOLUTE:
      return "V4L2_CID_TILT_ABSOLUTE";

    case V4L2_CID_ZOOM_ABSOLUTE:
      return "V4L2_CID_ZOOM_ABSOLUTE";

    case V4L2_CID_WHITE_BALANCE_TEMPERATURE:
      return "V4L2_CID_WHITE_BALANCE_TEMPERATURE";

    default:
      NOTREACHED() << "Unexpected cid " << cid;
      return "N/A";
  }
}

}  // namespace

V4L2CameraDevice::V4L2CameraDevice()
    : stream_on_(false),
      device_info_(DeviceInfo()),
      event_thread_("V4L2Event") {}

V4L2CameraDevice::V4L2CameraDevice(
    const DeviceInfo& device_info,
    CameraPrivacySwitchMonitor* privacy_switch_monitor)
    : stream_on_(false),
      device_info_(device_info),
      event_thread_("V4L2 Event Thread"),
      privacy_switch_monitor_(privacy_switch_monitor) {}

V4L2CameraDevice::~V4L2CameraDevice() {
  device_fd_.reset();
}

int V4L2CameraDevice::Connect(const std::string& device_path) {
  VLOGF(1) << "Connecting device path: " << device_path;
  base::AutoLock l(lock_);
  if (device_fd_.is_valid()) {
    LOGF(ERROR) << "A camera device is opened (" << device_fd_.get()
                << "). Please close it first";
    return -EIO;
  }

  // Since device node may be changed after suspend/resume, we allow to use
  // symbolic link to access device.
  device_fd_.reset(RetryDeviceOpen(device_path, O_RDWR));
  if (!device_fd_.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return -errno;
  }

  if (!IsCameraDevice(device_path)) {
    LOGF(ERROR) << device_path << " is not a V4L2 video capture device";
    device_fd_.reset();
    return -EINVAL;
  }

  // Get and set format here is used to prevent multiple camera using.
  // UVC driver will acquire lock in VIDIOC_S_FMT and VIDIOC_S_SMT will fail if
  // the camera is being used by a user. The second user will fail in Connect()
  // instead of StreamOn(). Usually apps show better error message if camera
  // open fails. If start preview fails, some apps do not handle it well.
  int ret;
  v4l2_format fmt = {};
  fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  ret = TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_G_FMT, &fmt));
  if (ret < 0) {
    PLOGF(ERROR) << "Unable to G_FMT";
    return -errno;
  }
  ret = TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_S_FMT, &fmt));
  if (ret < 0) {
    LOGF(WARNING) << "Unable to S_FMT: " << base::safe_strerror(errno)
                  << ", maybe camera is being used by another app.";
    return -errno;
  }

  // Only set power line frequency when the value is correct.
  if (device_info_.power_line_frequency != PowerLineFrequency::FREQ_ERROR) {
    ret = SetPowerLineFrequency(device_info_.power_line_frequency);
    if (ret < 0) {
      if (IsExternalCamera()) {
        VLOGF(2) << "Ignore SetPowerLineFrequency error for external camera";
      } else {
        return -EINVAL;
      }
    }
  }

  // Initial autofocus state.
  int32_t value;
  focus_auto_supported_ = IsControlSupported(kControlFocusAuto) &&
                          GetControlValue(kControlFocusAuto, &value) == 0;
  if (focus_auto_supported_) {
    LOGF(INFO) << "Device supports auto focus control, current mode is "
               << (value == 0 ? "Off" : "Auto");
  }
  focus_distance_supported_ = IsControlSupported(kControlFocusDistance);
  if (focus_distance_supported_) {
    LOGF(INFO) << "Device supports focus distance control";
    // Focus distance is valid when focus mode is off.
    if (value == 0 && GetControlValue(kControlFocusDistance, &value) == 0) {
      LOGF(INFO) << "Current distance is " << value;
    }
  }

  // Query the initial auto white balance state.
  white_balance_control_supported_ =
      IsControlSupported(kControlAutoWhiteBalance) &&
      IsControlSupported(kControlWhiteBalanceTemperature);
  if (white_balance_control_supported_) {
    LOGF(INFO) << "Device " << device_info_.camera_id
               << " supports white balance control";
    if (GetControlValue(kControlAutoWhiteBalance, &value) == 0) {
      if (value) {
        LOGF(INFO) << "Current white balance control is Auto";
      } else if (GetControlValue(kControlWhiteBalanceTemperature, &value) ==
                 0) {
        LOGF(INFO) << "Current white balance temperature is " << value;
      }
    }
  }

  ControlInfo info;
  ControlRange range;
  manual_exposure_time_supported_ =
      IsManualExposureTimeSupported(device_path, &range);
  if (manual_exposure_time_supported_ &&
      QueryControl(kControlExposureAuto, &info) == 0) {
    if (GetControlValue(kControlExposureAuto, &value) == 0) {
      switch (value) {
        case V4L2_EXPOSURE_AUTO:
          LOGF(INFO) << "Current exposure type is Auto";
          auto_exposure_time_type_ = V4L2_EXPOSURE_AUTO;
          // Prefer switching between AUTO<->SHUTTER_PRIORITY
          if (base::Contains(info.menu_items,
                             kExposureTypeMenuStringShutterPriority)) {
            manual_exposure_time_type_ = V4L2_EXPOSURE_SHUTTER_PRIORITY;
          } else if (base::Contains(info.menu_items,
                                    kExposureTypeMenuStringManual)) {
            manual_exposure_time_type_ = V4L2_EXPOSURE_MANUAL;
          } else {
            NOTREACHED() << "No manual exposure time type supported";
          }
          break;

        case V4L2_EXPOSURE_MANUAL:
          LOGF(INFO) << "Current exposure type is Manual";
          manual_exposure_time_type_ = V4L2_EXPOSURE_MANUAL;
          // Prefer switching between APERTURE_PRIORITY<->MANUAL
          if (base::Contains(info.menu_items,
                             kExposureTypeMenuStringAperturePriority)) {
            auto_exposure_time_type_ = V4L2_EXPOSURE_APERTURE_PRIORITY;
          } else if (base::Contains(info.menu_items,
                                    kExposureTypeMenuStringAuto)) {
            auto_exposure_time_type_ = V4L2_EXPOSURE_AUTO;
          } else {
            NOTREACHED() << "No auto exposure time type supported";
          }
          break;

        case V4L2_EXPOSURE_SHUTTER_PRIORITY:
          LOGF(INFO) << "Current exposure type is Shutter Priority";
          manual_exposure_time_type_ = V4L2_EXPOSURE_SHUTTER_PRIORITY;
          // Prefer switching between AUTO<->SHUTTER_PRIORITY
          if (base::Contains(info.menu_items, kExposureTypeMenuStringAuto)) {
            auto_exposure_time_type_ = V4L2_EXPOSURE_AUTO;
          } else if (base::Contains(info.menu_items,
                                    kExposureTypeMenuStringAperturePriority)) {
            auto_exposure_time_type_ = V4L2_EXPOSURE_APERTURE_PRIORITY;
          } else {
            NOTREACHED() << "No auto exposure time type supported";
          }
          break;

        case V4L2_EXPOSURE_APERTURE_PRIORITY:
          LOGF(INFO) << "Current exposure type is Aperture Priority";
          auto_exposure_time_type_ = V4L2_EXPOSURE_APERTURE_PRIORITY;
          // Prefer switching between APERTURE_PRIORITY<->MANUAL
          if (base::Contains(info.menu_items, kExposureTypeMenuStringManual)) {
            manual_exposure_time_type_ = V4L2_EXPOSURE_MANUAL;
          } else if (base::Contains(info.menu_items,
                                    kExposureTypeMenuStringShutterPriority)) {
            manual_exposure_time_type_ = V4L2_EXPOSURE_SHUTTER_PRIORITY;
          } else {
            NOTREACHED() << "No manual exposure time type supported";
          }
          break;

        default:
          LOGF(WARNING) << "Unknown exposure type " << value;
          manual_exposure_time_supported_ = false;
          break;
      }
    }
  }

  if (IsControlSupported(kControlPrivacy)) {
    ret = SubscribePrivacySwitchEvent();
    if (ret != 0) {
      LOGF(WARNING) << "Failed to subscribe privacy switch event: "
                    << base::safe_strerror(-ret);
    }
  }

  // Initialize the capabilities.
  if (device_info_.quirks & kQuirkDisableFrameRateSetting) {
    can_update_frame_rate_ = false;
  } else {
    v4l2_streamparm streamparm = {};
    streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    can_update_frame_rate_ =
        TEMP_FAILURE_RETRY(
            ioctl(device_fd_.get(), VIDIOC_G_PARM, &streamparm)) >= 0 &&
        (streamparm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME);
  }
  return 0;
}

void V4L2CameraDevice::Disconnect() {
  base::AutoLock l(lock_);
  stream_on_ = false;

  if (IsControlSupported(kControlPrivacy)) {
    int ret = UnsubscribePrivacySwitchEvent();
    if (ret != 0) {
      LOGF(WARNING) << "Failed to unsubscribe privacy switch event: "
                    << base::safe_strerror(-ret);
    }
    privacy_switch_monitor_->OnStatusChanged(PrivacySwitchState::kUnknown);
  }

  device_fd_.reset();
  buffers_at_client_.clear();
}

int V4L2CameraDevice::StreamOn(uint32_t width,
                               uint32_t height,
                               uint32_t pixel_format,
                               float frame_rate,
                               std::vector<base::ScopedFD>* fds,
                               std::vector<uint32_t>* buffer_sizes) {
  base::AutoLock l(lock_);
  if (!device_fd_.is_valid()) {
    LOGF(ERROR) << "Device is not opened";
    return -ENODEV;
  }
  if (stream_on_) {
    LOGF(ERROR) << "Device has stream already started";
    return -EIO;
  }

  int ret;

  // Some drivers use rational time per frame instead of float frame rate, this
  // constant k is used to convert between both: A fps -> [k/k*A] seconds/frame.
  v4l2_format fmt = {};
  fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  fmt.fmt.pix.width = width;
  fmt.fmt.pix.height = height;
  fmt.fmt.pix.pixelformat = pixel_format;
  ret = TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_S_FMT, &fmt));
  if (ret < 0) {
    PLOGF(ERROR) << "Unable to S_FMT";
    return -errno;
  }
  VLOGF(1) << "Actual width: " << fmt.fmt.pix.width
           << ", height: " << fmt.fmt.pix.height
           << ", pixelformat: " << std::hex << fmt.fmt.pix.pixelformat
           << std::dec;

  if (width != fmt.fmt.pix.width || height != fmt.fmt.pix.height ||
      pixel_format != fmt.fmt.pix.pixelformat) {
    LOGF(ERROR) << "Unsupported format: width " << width << ", height "
                << height << ", pixelformat " << pixel_format;
    return -EINVAL;
  }

  if (CanUpdateFrameRate()) {
    // We need to set frame rate even if it's same as the previous value, since
    // uvcvideo driver will always reset it to the default value after the
    // VIDIOC_S_FMT ioctl() call.
    ret = SetFrameRate(frame_rate);
    if (ret < 0) {
      return ret;
    }
  } else {
    // Simply assumes the frame rate is good if the device does not support
    // frame rate settings.
    frame_rate_ = frame_rate;
    LOGF(INFO) << "No fps setting support, " << frame_rate
               << " fps setting is ignored";
  }

  v4l2_requestbuffers req_buffers;
  memset(&req_buffers, 0, sizeof(req_buffers));
  req_buffers.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  req_buffers.memory = V4L2_MEMORY_MMAP;
  req_buffers.count = kNumVideoBuffers;
  if (TEMP_FAILURE_RETRY(
          ioctl(device_fd_.get(), VIDIOC_REQBUFS, &req_buffers)) < 0) {
    PLOGF(ERROR) << "REQBUFS fails";
    return -errno;
  }
  VLOGF(1) << "Requested buffer number: " << req_buffers.count;

  buffers_at_client_.resize(req_buffers.count);
  std::vector<base::ScopedFD> temp_fds;
  for (uint32_t i = 0; i < req_buffers.count; i++) {
    v4l2_exportbuffer expbuf;
    memset(&expbuf, 0, sizeof(expbuf));
    expbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    expbuf.index = i;
    if (TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_EXPBUF, &expbuf)) <
        0) {
      PLOGF(ERROR) << "EXPBUF (" << i << ") fails";
      return -errno;
    }
    VLOGF(1) << "Exported frame buffer fd: " << expbuf.fd;
    temp_fds.push_back(base::ScopedFD(expbuf.fd));
    buffers_at_client_[i] = false;

    v4l2_buffer buffer = {};
    buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buffer.index = i;
    buffer.memory = V4L2_MEMORY_MMAP;

    if (TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_QBUF, &buffer)) < 0) {
      PLOGF(ERROR) << "QBUF (" << i << ") fails";
      return -errno;
    }

    buffer_sizes->push_back(buffer.length);
  }

  v4l2_buf_type capture_type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  if (TEMP_FAILURE_RETRY(
          ioctl(device_fd_.get(), VIDIOC_STREAMON, &capture_type)) < 0) {
    PLOGF(ERROR) << "STREAMON fails";
    return -errno;
  }

  for (size_t i = 0; i < temp_fds.size(); i++) {
    fds->push_back(std::move(temp_fds[i]));
  }

  // Query for the initial value of privacy button status while streaming on if
  // it is supported.
  if (IsControlSupported(kControlPrivacy)) {
    int32_t value;
    if (GetControlValue(kControlPrivacy, &value) == 0) {
      privacy_switch_monitor_->OnStatusChanged(
          value != 0 ? PrivacySwitchState::kOn : PrivacySwitchState::kOff);
    } else {
      LOGF(ERROR)
          << "Failed to get the initial status of camera privacy switch";
    }
  }

  stream_on_ = true;
  return 0;
}

int V4L2CameraDevice::StreamOff() {
  base::AutoLock l(lock_);
  if (!device_fd_.is_valid()) {
    LOGF(ERROR) << "Device is not opened";
    return -ENODEV;
  }
  // Because UVC driver cannot allow STREAMOFF after REQBUF(0), adding a check
  // here to prevent it.
  if (!stream_on_) {
    return 0;
  }

  v4l2_buf_type capture_type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  if (TEMP_FAILURE_RETRY(
          ioctl(device_fd_.get(), VIDIOC_STREAMOFF, &capture_type)) < 0) {
    PLOGF(ERROR) << "STREAMOFF fails";
    return -errno;
  }
  v4l2_requestbuffers req_buffers;
  memset(&req_buffers, 0, sizeof(req_buffers));
  req_buffers.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  req_buffers.memory = V4L2_MEMORY_MMAP;
  req_buffers.count = 0;
  if (TEMP_FAILURE_RETRY(
          ioctl(device_fd_.get(), VIDIOC_REQBUFS, &req_buffers)) < 0) {
    PLOGF(ERROR) << "REQBUFS fails";
    return -errno;
  }
  buffers_at_client_.clear();
  stream_on_ = false;
  return 0;
}

int V4L2CameraDevice::GetNextFrameBuffer(uint32_t* buffer_id,
                                         uint32_t* data_size,
                                         uint64_t* v4l2_ts,
                                         uint64_t* user_ts) {
  base::AutoLock l(lock_);
  if (!device_fd_.is_valid()) {
    LOGF(ERROR) << "Device is not opened";
    return -ENODEV;
  }
  if (!stream_on_) {
    LOGF(ERROR) << "Streaming is not started";
    return -EIO;
  }

  if (device_info_.quirks & kQuirkRestartOnTimeout) {
    pollfd device_pfd = {};
    device_pfd.fd = device_fd_.get();
    device_pfd.events = POLLIN;

    constexpr int kCaptureTimeoutMs = 1000;
    const int result =
        TEMP_FAILURE_RETRY(poll(&device_pfd, 1, kCaptureTimeoutMs));

    if (result < 0) {
      PLOGF(ERROR) << "Polling fails";
      return -errno;
    } else if (result == 0) {
      LOGF(ERROR) << "Timed out waiting for captured frame";
      return -ETIMEDOUT;
    }

    if (!(device_pfd.revents & POLLIN)) {
      LOGF(ERROR) << "Unexpected event occurred while polling";
      return -EIO;
    }
  }

  v4l2_buffer buffer;
  memset(&buffer, 0, sizeof(buffer));
  buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  buffer.memory = V4L2_MEMORY_MMAP;
  if (TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_DQBUF, &buffer)) < 0) {
    PLOGF(ERROR) << "DQBUF fails";
    return -errno;
  }
  VLOGF(1) << "DQBUF returns index " << buffer.index << " length "
           << buffer.length;

  if (buffer.index >= buffers_at_client_.size() ||
      buffers_at_client_[buffer.index]) {
    LOGF(ERROR) << "Invalid buffer id " << buffer.index;
    return -EINVAL;
  }

  *buffer_id = buffer.index;
  *data_size = buffer.bytesused;

  struct timeval tv = buffer.timestamp;
  *v4l2_ts = tv.tv_sec * 1'000'000'000LL + tv.tv_usec * 1000;

  struct timespec ts;
  if (clock_gettime(GetUvcClock(), &ts) < 0) {
    LOGF(ERROR) << "Get clock time fails";
    return -errno;
  }

  *user_ts = ts.tv_sec * 1'000'000'000LL + ts.tv_nsec;

  buffers_at_client_[buffer.index] = true;

  return 0;
}

int V4L2CameraDevice::ReuseFrameBuffer(uint32_t buffer_id) {
  base::AutoLock l(lock_);
  if (!device_fd_.is_valid()) {
    LOGF(ERROR) << "Device is not opened";
    return -ENODEV;
  }
  if (!stream_on_) {
    LOGF(ERROR) << "Streaming is not started";
    return -EIO;
  }

  VLOGF(1) << "Reuse buffer id: " << buffer_id;
  if (buffer_id >= buffers_at_client_.size() ||
      !buffers_at_client_[buffer_id]) {
    LOGF(ERROR) << "Invalid buffer id: " << buffer_id;
    return -EINVAL;
  }
  v4l2_buffer buffer;
  memset(&buffer, 0, sizeof(buffer));
  buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  buffer.memory = V4L2_MEMORY_MMAP;
  buffer.index = buffer_id;
  if (TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_QBUF, &buffer)) < 0) {
    PLOGF(ERROR) << "QBUF fails";
    return -errno;
  }
  buffers_at_client_[buffer.index] = false;
  return 0;
}

bool V4L2CameraDevice::IsBufferFilled(uint32_t buffer_id) {
  v4l2_buffer buffer = {};
  buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  buffer.memory = V4L2_MEMORY_MMAP;
  buffer.index = buffer_id;
  if (TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_QUERYBUF, &buffer)) <
      0) {
    PLOGF(ERROR) << "QUERYBUF fails";
    return false;
  }
  return buffer.flags & V4L2_BUF_FLAG_DONE;
}

int V4L2CameraDevice::SetAutoFocus(bool enable) {
  if (!focus_auto_supported_) {
    // Off mode is default supported
    if (enable) {
      LOGF(WARNING)
          << "Setting auto focus while device doesn't support. Ignored";
    }
    return 0;
  }

  if (enable && control_values_.count(kControlFocusDistance)) {
    control_values_.erase(kControlFocusDistance);
  }

  return SetControlValue(kControlFocusAuto, enable ? 1 : 0);
}

int V4L2CameraDevice::SetFocusDistance(int32_t distance) {
  if (!focus_distance_supported_) {
    LOGF(WARNING) << "Setting focus distance while devcie doesn't support. "
                  << "Ignored.";
    return 0;
  }

  return SetControlValue(kControlFocusDistance, distance);
}

int V4L2CameraDevice::SetExposureTimeHundredUs(uint32_t exposure_time) {
  if (!manual_exposure_time_supported_) {
    if (exposure_time != kExposureTimeAuto) {
      LOGF(WARNING)
          << "Setting manual exposure time when device doesn't support";
    }
    return 0;
  }

  if (exposure_time == kExposureTimeAuto) {
    if (control_values_.count(kControlExposureTime))
      control_values_.erase(kControlExposureTime);
    return SetControlValue(kControlExposureAuto, auto_exposure_time_type_);
  }

  int ret = SetControlValue(kControlExposureAuto, manual_exposure_time_type_);
  if (ret != 0)
    return ret;

  return SetControlValue(kControlExposureTime, exposure_time);
}

bool V4L2CameraDevice::CanUpdateFrameRate() {
  return can_update_frame_rate_;
}

float V4L2CameraDevice::GetFrameRate() {
  return frame_rate_;
}

int V4L2CameraDevice::SetFrameRate(float frame_rate) {
  const int kFrameRatePrecision = 10000;

  if (!device_fd_.is_valid()) {
    LOGF(ERROR) << "Device is not opened";
    return -ENODEV;
  }

  v4l2_streamparm streamparm = {};
  streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

  // The following line checks that the driver knows about framerate get/set.
  if (TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_G_PARM, &streamparm)) >=
      0) {
    // |frame_rate| is float, approximate by a fraction.
    streamparm.parm.capture.timeperframe.numerator = kFrameRatePrecision;
    streamparm.parm.capture.timeperframe.denominator =
        (frame_rate * kFrameRatePrecision);

    if (TEMP_FAILURE_RETRY(
            ioctl(device_fd_.get(), VIDIOC_S_PARM, &streamparm)) < 0) {
      LOGF(ERROR) << "Failed to set camera framerate";
      return -errno;
    }
    VLOGF(1) << "Actual camera driver framerate: "
             << streamparm.parm.capture.timeperframe.denominator << "/"
             << streamparm.parm.capture.timeperframe.numerator;
    float fps =
        static_cast<float>(streamparm.parm.capture.timeperframe.denominator) /
        streamparm.parm.capture.timeperframe.numerator;
    if (std::fabs(fps - frame_rate) > kFpsDifferenceThreshold) {
      LOGF(ERROR) << "Unsupported frame rate " << frame_rate;
      return -EINVAL;
    }

    VLOGF(1) << "Successfully set the frame rate to: " << fps;
    frame_rate_ = frame_rate;
  }

  return 0;
}

int V4L2CameraDevice::SetColorTemperature(uint32_t color_temperature) {
  if (!white_balance_control_supported_) {
    if (color_temperature != kColorTemperatureAuto) {
      LOGF(WARNING) << "Setting color temperature when device doesn't support";
    }
    return 0;
  }

  if (color_temperature == kColorTemperatureAuto) {
    if (control_values_.count(kControlWhiteBalanceTemperature))
      control_values_.erase(kControlWhiteBalanceTemperature);
    return SetControlValue(kControlAutoWhiteBalance, 1);
  }

  int ret = SetControlValue(kControlAutoWhiteBalance, 0);
  if (ret != 0) {
    LOGF(WARNING) << "Failed to set white_balance_control to manual";
    return ret;
  }

  return SetControlValue(kControlWhiteBalanceTemperature, color_temperature);
}

int V4L2CameraDevice::SetControlValue(ControlType type, int32_t value) {
  auto it = control_values_.find(type);
  // Has cached value
  if (it != control_values_.end()) {
    if (it->second == value)
      return 0;
    else
      control_values_.erase(type);
  }

  int ret = SetControlValue(device_fd_.get(), type, value);
  if (ret != 0)
    return ret;
  LOGF(INFO) << "Set " << ControlTypeToString(type) << " to " << value;

  int32_t current_value;

  ret = GetControlValue(type, &current_value);
  if (ret != 0)
    return ret;
  LOGF(INFO) << "Get " << ControlTypeToString(type) << " " << current_value;

  return 0;
}

int V4L2CameraDevice::GetControlValue(ControlType type, int32_t* value) {
  auto it = control_values_.find(type);
  // Has cached value
  if (it != control_values_.end()) {
    *value = it->second;
    return 0;
  }

  int ret = GetControlValue(device_fd_.get(), type, value);
  if (ret != 0)
    return ret;

  control_values_[type] = *value;
  return 0;
}

bool V4L2CameraDevice::IsControlSupported(ControlType type) {
  ControlInfo info;

  return QueryControl(device_fd_.get(), type, &info) == 0;
}

int V4L2CameraDevice::QueryControl(ControlType type, ControlInfo* info) {
  return QueryControl(device_fd_.get(), type, info);
}

// static
const SupportedFormats V4L2CameraDevice::GetDeviceSupportedFormats(
    const std::string& device_path) {
  VLOGF(1) << "Query supported formats for " << device_path;

  base::ScopedFD fd(RetryDeviceOpen(device_path, O_RDONLY));
  if (!fd.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return {};
  }

  std::vector<std::string> filter_out_resolution_strings =
      CameraConfig::Create(constants::kCrosCameraConfigPathString)
          ->GetStrings(constants::kCrosFilteredOutResolutions,
                       std::vector<std::string>());

  std::vector<Size> filter_out_resolutions;
  for (const auto& filter_out_resolution_string :
       filter_out_resolution_strings) {
    int width, height;
    CHECK(RE2::FullMatch(filter_out_resolution_string, R"((\d+)x(\d+))", &width,
                         &height));
    filter_out_resolutions.emplace_back(width, height);
  }

  SupportedFormats formats;
  v4l2_fmtdesc v4l2_format = {};
  v4l2_format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  for (;
       TEMP_FAILURE_RETRY(ioctl(fd.get(), VIDIOC_ENUM_FMT, &v4l2_format)) == 0;
       ++v4l2_format.index) {
    SupportedFormat supported_format;
    supported_format.fourcc = v4l2_format.pixelformat;

    v4l2_frmsizeenum frame_size = {};
    frame_size.pixel_format = v4l2_format.pixelformat;
    for (; HANDLE_EINTR(ioctl(fd.get(), VIDIOC_ENUM_FRAMESIZES, &frame_size)) ==
           0;
         ++frame_size.index) {
      if (frame_size.type == V4L2_FRMSIZE_TYPE_DISCRETE) {
        supported_format.width = frame_size.discrete.width;
        supported_format.height = frame_size.discrete.height;
      } else if (frame_size.type == V4L2_FRMSIZE_TYPE_STEPWISE ||
                 frame_size.type == V4L2_FRMSIZE_TYPE_CONTINUOUS) {
        // TODO(henryhsu): see http://crbug.com/249953, support these devices.
        LOGF(ERROR) << "Stepwise and continuous frame size are unsupported";
        return formats;
      }
      bool is_filtered_out =
          base::Contains(filter_out_resolutions,
                         Size(supported_format.width, supported_format.height));
      if (is_filtered_out) {
        LOGF(INFO) << "Filter " << supported_format.width << "x"
                   << supported_format.height;
        continue;
      }

      supported_format.frame_rates = GetFrameRateList(
          fd.get(), v4l2_format.pixelformat, frame_size.discrete.width,
          frame_size.discrete.height);
      formats.push_back(supported_format);
    }
  }
  return formats;
}

// static
int V4L2CameraDevice::QueryControl(int fd,
                                   ControlType type,
                                   ControlInfo* info) {
  DCHECK(info);

  info->menu_items.clear();

  int control_id = ControlTypeToCid(type);
  v4l2_queryctrl query_ctrl = {.id = static_cast<__u32>(control_id)};

  if (HANDLE_EINTR(ioctl(fd, VIDIOC_QUERYCTRL, &query_ctrl)) < 0) {
    VLOGF(1) << "Unsupported control:" << CidToString(control_id);
    return -errno;
  }

  if (query_ctrl.flags & V4L2_CTRL_FLAG_DISABLED) {
    LOGF(WARNING) << "Disabled control:" << CidToString(control_id);
    return -EPERM;
  }

  switch (query_ctrl.type) {
    case V4L2_CTRL_TYPE_INTEGER:
    case V4L2_CTRL_TYPE_BOOLEAN:
    case V4L2_CTRL_TYPE_MENU:
    case V4L2_CTRL_TYPE_STRING:
    case V4L2_CTRL_TYPE_INTEGER_MENU:
    case V4L2_CTRL_TYPE_U8:
    case V4L2_CTRL_TYPE_U16:
    case V4L2_CTRL_TYPE_U32:
      break;

    case V4L2_CTRL_TYPE_INTEGER64:
      LOGF(WARNING) << "Unsupported query V4L2_CTRL_TYPE_INTEGER64:"
                    << CidToString(control_id);
      return -EINVAL;

    default:
      info->range.minimum = query_ctrl.minimum;
      info->range.maximum = query_ctrl.maximum;
      info->range.step = query_ctrl.step;
      info->range.default_value = query_ctrl.default_value;
      return 0;
  }

  if (query_ctrl.minimum > query_ctrl.maximum) {
    LOGF(WARNING) << CidToString(control_id) << " min " << query_ctrl.minimum
                  << " > max " << query_ctrl.maximum;
    return -EINVAL;
  }

  if (query_ctrl.minimum > query_ctrl.default_value) {
    LOGF(WARNING) << CidToString(control_id) << " min " << query_ctrl.minimum
                  << " > default " << query_ctrl.default_value;
    return -EINVAL;
  }

  if (query_ctrl.maximum < query_ctrl.default_value) {
    LOGF(WARNING) << CidToString(control_id) << " max " << query_ctrl.maximum
                  << " < default " << query_ctrl.default_value;
    return -EINVAL;
  }

  if (query_ctrl.step <= 0) {
    LOGF(WARNING) << CidToString(control_id) << " step " << query_ctrl.step
                  << " <= 0";
    return -EINVAL;
  }

  if ((query_ctrl.default_value - query_ctrl.minimum) % query_ctrl.step != 0) {
    LOGF(WARNING) << CidToString(control_id) << " step " << query_ctrl.step
                  << " can't divide minimum " << query_ctrl.minimum
                  << " default_value " << query_ctrl.default_value;
    return -EINVAL;
  }

  if ((query_ctrl.maximum - query_ctrl.minimum) % query_ctrl.step != 0) {
    LOGF(WARNING) << CidToString(control_id) << " step " << query_ctrl.step
                  << " can't divide minimum " << query_ctrl.minimum
                  << " maximum " << query_ctrl.maximum;
    return -EINVAL;
  }

  // Fill the query info
  info->range.minimum = query_ctrl.minimum;
  info->range.maximum = query_ctrl.maximum;
  info->range.step = query_ctrl.step;
  info->range.default_value = query_ctrl.default_value;
  if (query_ctrl.type == V4L2_CTRL_TYPE_MENU) {
    for (int i = query_ctrl.minimum; i <= query_ctrl.maximum; i++) {
      v4l2_querymenu qmenu = {};
      qmenu.id = query_ctrl.id;
      qmenu.index = i;
      if (HANDLE_EINTR(ioctl(fd, VIDIOC_QUERYMENU, &qmenu)) == 0) {
        info->menu_items.emplace_back(
            reinterpret_cast<const char*>(qmenu.name));
      }
    }
  }

  return 0;
}

// static
int V4L2CameraDevice::SetControlValue(int fd, ControlType type, int32_t value) {
  int control_id = ControlTypeToCid(type);
  VLOGF(1) << "Set " << CidToString(control_id) << ", value:" << value;

  v4l2_control current = {.id = static_cast<__u32>(control_id), .value = value};
  if (HANDLE_EINTR(ioctl(fd, VIDIOC_S_CTRL, &current)) < 0) {
    PLOGF(WARNING) << "Failed to set " << CidToString(control_id) << " to "
                   << value;
    return -errno;
  }

  return 0;
}

// static
int V4L2CameraDevice::GetControlValue(int fd,
                                      ControlType type,
                                      int32_t* value) {
  DCHECK(value);

  int control_id = ControlTypeToCid(type);
  v4l2_control current = {.id = static_cast<__u32>(control_id)};

  if (HANDLE_EINTR(ioctl(fd, VIDIOC_G_CTRL, &current)) < 0) {
    PLOGF(WARNING) << "Failed to get " << CidToString(control_id);
    return -errno;
  }
  *value = current.value;

  VLOGF(1) << "Get " << CidToString(control_id) << ", value:" << *value;

  return 0;
}

// static
std::vector<float> V4L2CameraDevice::GetFrameRateList(int fd,
                                                      uint32_t fourcc,
                                                      uint32_t width,
                                                      uint32_t height) {
  std::vector<float> frame_rates;

  v4l2_frmivalenum frame_interval = {};
  frame_interval.pixel_format = fourcc;
  frame_interval.width = width;
  frame_interval.height = height;
  for (; TEMP_FAILURE_RETRY(
             ioctl(fd, VIDIOC_ENUM_FRAMEINTERVALS, &frame_interval)) == 0;
       ++frame_interval.index) {
    if (frame_interval.type == V4L2_FRMIVAL_TYPE_DISCRETE) {
      if (frame_interval.discrete.numerator != 0) {
        frame_rates.push_back(
            frame_interval.discrete.denominator /
            static_cast<float>(frame_interval.discrete.numerator));
      }
    } else if (frame_interval.type == V4L2_FRMIVAL_TYPE_CONTINUOUS ||
               frame_interval.type == V4L2_FRMIVAL_TYPE_STEPWISE) {
      // TODO(henryhsu): see http://crbug.com/249953, support these devices.
      LOGF(ERROR) << "Stepwise and continuous frame interval are unsupported";
      return frame_rates;
    }
  }
  // Some devices, e.g. Kinect, do not enumerate any frame rates, see
  // http://crbug.com/412284. Set their frame_rate to zero.
  if (frame_rates.empty()) {
    frame_rates.push_back(0);
  }
  return frame_rates;
}

// static
bool V4L2CameraDevice::IsCameraDevice(const std::string& device_path) {
  // RetryDeviceOpen() assumes the device is a camera and waits until the camera
  // is ready, so we use open() instead of RetryDeviceOpen() here.
  base::ScopedFD fd(TEMP_FAILURE_RETRY(open(device_path.c_str(), O_RDONLY)));
  if (!fd.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return false;
  }

  v4l2_capability v4l2_cap;
  if (TEMP_FAILURE_RETRY(ioctl(fd.get(), VIDIOC_QUERYCAP, &v4l2_cap)) != 0) {
    return false;
  }

  auto check_mask = [](uint32_t caps) {
    const uint32_t kCaptureMask =
        V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VIDEO_CAPTURE_MPLANE;
    // Old drivers use (CAPTURE | OUTPUT) for memory-to-memory video devices.
    const uint32_t kOutputMask =
        V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_VIDEO_OUTPUT_MPLANE;
    const uint32_t kM2mMask = V4L2_CAP_VIDEO_M2M | V4L2_CAP_VIDEO_M2M_MPLANE;
    return (caps & kCaptureMask) && !(caps & kOutputMask) && !(caps & kM2mMask);
  };

  // Prefer to use available capabilities of that specific device node instead
  // of the physical device as a whole, so we can properly ignore the metadata
  // device node.
  if (v4l2_cap.capabilities & V4L2_CAP_DEVICE_CAPS) {
    return check_mask(v4l2_cap.device_caps);
  } else {
    return check_mask(v4l2_cap.capabilities);
  }
}

// static
std::string V4L2CameraDevice::GetModelName(const std::string& device_path) {
  auto get_by_interface = [&](std::string* name) {
    base::FilePath real_path;
    if (!base::NormalizeFilePath(base::FilePath(device_path), &real_path)) {
      return false;
    }
    if (!base::MatchPattern(real_path.value(), "/dev/video*")) {
      return false;
    }
    // /sys/class/video4linux/video{N}/device is a symlink to the corresponding
    // USB device info directory.
    auto interface_path = base::FilePath("/sys/class/video4linux")
                              .Append(real_path.BaseName())
                              .Append("device/interface");
    return base::ReadFileToString(interface_path, name);
  };

  auto get_by_cap = [&](std::string* name) {
    base::ScopedFD fd(RetryDeviceOpen(device_path, O_RDONLY));
    if (!fd.is_valid()) {
      PLOGF(WARNING) << "Failed to open " << device_path;
      return false;
    }

    v4l2_capability cap;
    if (TEMP_FAILURE_RETRY(ioctl(fd.get(), VIDIOC_QUERYCAP, &cap)) != 0) {
      PLOGF(WARNING) << "Failed to query capability of " << device_path;
      return false;
    }
    *name = std::string(reinterpret_cast<const char*>(cap.card));
    return true;
  };

  std::string name;
  if (get_by_interface(&name)) {
    return name;
  }
  if (get_by_cap(&name)) {
    return name;
  }
  return "USB Camera";
}

// static
bool V4L2CameraDevice::IsControlSupported(const std::string& device_path,
                                          ControlType type) {
  ControlInfo info;
  return QueryControl(device_path, type, &info) == 0;
}

// static
int V4L2CameraDevice::QueryControl(const std::string& device_path,
                                   ControlType type,
                                   ControlInfo* info) {
  base::ScopedFD fd(RetryDeviceOpen(device_path, O_RDONLY));
  if (!fd.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return -errno;
  }

  int ret = QueryControl(fd.get(), type, info);
  if (ret != 0) {
    return ret;
  }

  LOGF(INFO) << ControlTypeToString(type) << "(min,max,step,default) = "
             << "(" << info->range.minimum << "," << info->range.maximum << ","
             << info->range.step << "," << info->range.default_value << ")";

  if (!info->menu_items.empty()) {
    LOGF(INFO) << ControlTypeToString(type) << " " << info->menu_items.size()
               << " menu items:";
    for (const auto& item : info->menu_items)
      LOGF(INFO) << "    " << item;
  }

  return 0;
}

// static
int V4L2CameraDevice::GetControlValue(const std::string& device_path,
                                      ControlType type,
                                      int32_t* value) {
  base::ScopedFD fd(RetryDeviceOpen(device_path, O_RDONLY));
  if (!fd.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return -errno;
  }

  return GetControlValue(fd.get(), type, value);
}

// static
int V4L2CameraDevice::SetControlValue(const std::string& device_path,
                                      ControlType type,
                                      int32_t value) {
  base::ScopedFD fd(RetryDeviceOpen(device_path, O_RDONLY));
  if (!fd.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return -errno;
  }

  return SetControlValue(fd.get(), type, value);
}

// static
int V4L2CameraDevice::RetryDeviceOpen(const std::string& device_path,
                                      int flags) {
  const int64_t kDeviceOpenTimeOutInMilliseconds = 2000;
  const int64_t kSleepTimeInMilliseconds = 100;
  int fd;
  base::ElapsedTimer timer;
  int64_t elapsed_time = timer.Elapsed().InMillisecondsRoundedUp();
  while (elapsed_time < kDeviceOpenTimeOutInMilliseconds) {
    fd = TEMP_FAILURE_RETRY(open(device_path.c_str(), flags));
    if (fd != -1) {
      // Make sure ioctl is ok. Once ioctl failed, we have to re-open the
      // device.
      struct v4l2_fmtdesc v4l2_format = {};
      v4l2_format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
      int ret = TEMP_FAILURE_RETRY(ioctl(fd, VIDIOC_ENUM_FMT, &v4l2_format));
      if (ret == -1) {
        close(fd);
        if (errno != EPERM) {
          break;
        } else {
          VLOGF(1) << "Camera ioctl is not ready";
        }
      } else {
        // Only return fd when ioctl is ready.
        if (elapsed_time >= kSleepTimeInMilliseconds) {
          LOGF(INFO) << "Opened the camera device after waiting for "
                     << elapsed_time << " ms";
        }
        return fd;
      }
    } else if (errno != ENOENT) {
      break;
    }
    base::PlatformThread::Sleep(
        base::TimeDelta::FromMilliseconds(kSleepTimeInMilliseconds));
    elapsed_time = timer.Elapsed().InMillisecondsRoundedUp();
  }
  PLOGF(ERROR) << "Failed to open " << device_path;
  return -1;
}

// static
clockid_t V4L2CameraDevice::GetUvcClock() {
  static const clockid_t kUvcClock = [] {
    const base::FilePath kClockPath("/sys/module/uvcvideo/parameters/clock");
    std::string clock;
    if (base::ReadFileToString(kClockPath, &clock)) {
      if (clock.find("REALTIME") != std::string::npos) {
        return CLOCK_REALTIME;
      } else if (clock.find("BOOTTIME") != std::string::npos) {
        return CLOCK_BOOTTIME;
      } else {
        return CLOCK_MONOTONIC;
      }
    }
    // Use UVC default clock.
    return CLOCK_MONOTONIC;
  }();
  return kUvcClock;
}

// static
PowerLineFrequency V4L2CameraDevice::GetPowerLineFrequency(
    const std::string& device_path) {
  base::ScopedFD fd(RetryDeviceOpen(device_path, O_RDONLY));
  if (!fd.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return PowerLineFrequency::FREQ_ERROR;
  }

  struct v4l2_queryctrl query = {};
  query.id = V4L2_CID_POWER_LINE_FREQUENCY;
  if (TEMP_FAILURE_RETRY(ioctl(fd.get(), VIDIOC_QUERYCTRL, &query)) < 0) {
    LOGF(ERROR) << "Power line frequency should support auto or 50/60Hz";
    return PowerLineFrequency::FREQ_ERROR;
  }

  PowerLineFrequency frequency = GetPowerLineFrequencyForLocation();
  if (frequency == PowerLineFrequency::FREQ_DEFAULT) {
    switch (query.default_value) {
      case V4L2_CID_POWER_LINE_FREQUENCY_50HZ:
        frequency = PowerLineFrequency::FREQ_50HZ;
        break;
      case V4L2_CID_POWER_LINE_FREQUENCY_60HZ:
        frequency = PowerLineFrequency::FREQ_60HZ;
        break;
      case V4L2_CID_POWER_LINE_FREQUENCY_AUTO:
        frequency = PowerLineFrequency::FREQ_AUTO;
        break;
      default:
        break;
    }
  }

  // Prefer auto setting if camera module supports auto mode.
  if (query.maximum == V4L2_CID_POWER_LINE_FREQUENCY_AUTO) {
    frequency = PowerLineFrequency::FREQ_AUTO;
  } else if (query.minimum >= V4L2_CID_POWER_LINE_FREQUENCY_60HZ) {
    // TODO(shik): Handle this more gracefully for external camera
    LOGF(ERROR) << "Camera module should at least support 50/60Hz";
    return PowerLineFrequency::FREQ_ERROR;
  }
  return frequency;
}

// static
bool V4L2CameraDevice::IsFocusDistanceSupported(
    const std::string& device_path, ControlRange* focus_distance_range) {
  DCHECK(focus_distance_range != nullptr);

  if (!IsControlSupported(device_path, kControlFocusAuto))
    return false;

  ControlInfo info;
  if (QueryControl(device_path, kControlFocusDistance, &info) != 0) {
    return false;
  }

  *focus_distance_range = info.range;

  return true;
}

// static
bool V4L2CameraDevice::IsManualExposureTimeSupported(
    const std::string& device_path, ControlRange* exposure_time_range) {
  ControlInfo info;

  DCHECK(exposure_time_range);

  if (QueryControl(device_path, kControlExposureAuto, &info) != 0)
    return false;

  bool found_manual_type = false;
  bool found_auto_type = false;
  for (const auto& item : info.menu_items) {
    if (item == kExposureTypeMenuStringManual) {
      found_manual_type = true;
    } else if (item == kExposureTypeMenuStringShutterPriority) {
      found_manual_type = true;
    } else if (item == kExposureTypeMenuStringAuto) {
      found_auto_type = true;
    } else if (item == kExposureTypeMenuStringAperturePriority) {
      found_auto_type = true;
    }
  }

  if (!found_manual_type || !found_auto_type)
    return false;

  if (QueryControl(device_path, kControlExposureTime, &info) != 0) {
    LOG(WARNING) << "Can't get exposure time range";
    return false;
  }
  *exposure_time_range = info.range;

  return true;
}

// static
bool V4L2CameraDevice::IsConstantFrameRateSupported(
    const std::string& device_path) {
  base::ScopedFD fd(RetryDeviceOpen(device_path, O_RDONLY));
  if (!fd.is_valid()) {
    PLOGF(ERROR) << "Failed to open " << device_path;
    return false;
  }
  struct v4l2_queryctrl query_ctrl;
  query_ctrl.id = V4L2_CID_EXPOSURE_AUTO_PRIORITY;
  if (TEMP_FAILURE_RETRY(ioctl(fd.get(), VIDIOC_QUERYCTRL, &query_ctrl)) < 0) {
    LOGF(WARNING) << "Failed to query V4L2_CID_EXPOSURE_AUTO_PRIORITY";
    return false;
  }
  return !(query_ctrl.flags & V4L2_CTRL_FLAG_DISABLED);
}

int V4L2CameraDevice::SetPowerLineFrequency(PowerLineFrequency setting) {
  int v4l2_freq_setting = V4L2_CID_POWER_LINE_FREQUENCY_DISABLED;
  switch (setting) {
    case PowerLineFrequency::FREQ_50HZ:
      v4l2_freq_setting = V4L2_CID_POWER_LINE_FREQUENCY_50HZ;
      break;
    case PowerLineFrequency::FREQ_60HZ:
      v4l2_freq_setting = V4L2_CID_POWER_LINE_FREQUENCY_60HZ;
      break;
    case PowerLineFrequency::FREQ_AUTO:
      v4l2_freq_setting = V4L2_CID_POWER_LINE_FREQUENCY_AUTO;
      break;
    default:
      LOGF(ERROR) << "Invalid setting for power line frequency: "
                  << static_cast<int>(setting);
      return -EINVAL;
  }

  struct v4l2_control control = {};
  control.id = V4L2_CID_POWER_LINE_FREQUENCY;
  control.value = v4l2_freq_setting;
  if (TEMP_FAILURE_RETRY(ioctl(device_fd_.get(), VIDIOC_S_CTRL, &control)) <
      0) {
    LOGF(ERROR) << "Error setting power line frequency to "
                << v4l2_freq_setting;
    return -EINVAL;
  }
  VLOGF(1) << "Set power line frequency(" << static_cast<int>(setting)
           << ") successfully";
  return 0;
}

bool V4L2CameraDevice::IsExternalCamera() {
  return device_info_.lens_facing == LensFacing::kExternal;
}

int V4L2CameraDevice::SubscribePrivacySwitchEvent() {
  struct v4l2_event_subscription sub = {.type = V4L2_EVENT_CTRL,
                                        .id = V4L2_CID_PRIVACY};
  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_SUBSCRIBE_EVENT, &sub)) < 0) {
    LOGF(ERROR) << "Unable to subscribe for privacy status change";
    return -errno;
  }

  if (!base::CreatePipe(&cancel_fd_, &cancel_pipe_, true)) {
    LOGF(ERROR) << "Failed to create the cancelation pipe";
    return -EINVAL;
  }

  DCHECK(!event_thread_.IsRunning());
  if (!event_thread_.Start()) {
    LOGF(ERROR) << "Failed to start V4L2 event thread";
    return -EINVAL;
  }

  event_thread_.task_runner()->PostTask(
      FROM_HERE, base::BindRepeating(&V4L2CameraDevice::RunDequeueEventsLoop,
                                     base::Unretained(this)));
  return 0;
}

int V4L2CameraDevice::UnsubscribePrivacySwitchEvent() {
  cancel_pipe_.reset();
  if (event_thread_.IsRunning()) {
    event_thread_.Stop();
  }

  struct v4l2_event_subscription sub = {.type = V4L2_EVENT_CTRL,
                                        .id = V4L2_CID_PRIVACY};
  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_UNSUBSCRIBE_EVENT, &sub)) <
      0) {
    LOGF(ERROR) << "Unable to unsubscribe for privacy status change";
    return -errno;
  }
  return 0;
}

void V4L2CameraDevice::RunDequeueEventsLoop() {
  while (true) {
    struct pollfd fds[2] = {
        {device_fd_.get(), POLLPRI, 0},
        {cancel_fd_.get(), POLLHUP, 0},
    };

    if (HANDLE_EINTR(poll(fds, base::size(fds), -1)) <= 0) {
      LOGF(ERROR) << "Failed to poll to dequeue events";
      return;
    }

    if (fds[1].revents > 0) {
      cancel_fd_.reset();
      return;
    }

    if (fds[0].revents > 0) {
      struct v4l2_event ev = {};
      if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_DQEVENT, &ev)) == 0) {
        if (ev.type == V4L2_EVENT_CTRL && ev.id == V4L2_CID_PRIVACY &&
            privacy_switch_monitor_) {
          privacy_switch_monitor_->OnStatusChanged(
              ev.u.ctrl.value != 0 ? PrivacySwitchState::kOn
                                   : PrivacySwitchState::kOff);
        }
      } else {
        LOGF(ERROR) << "Failed to dequeue event from device";
      }
    }
  }
}

}  // namespace cros