src/ledservice/ledstatus.cc

/*
 * Copyright 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "ledstatus.h"

#include <string>

#include <base/files/file_path.h>
#include <base/format_macros.h>
#include <base/logging.h>
#include <base/strings/stringprintf.h>
#include <base/strings/string_number_conversions.h>
#include <base/strings/string_util.h>
#include <chromeos/streams/file_stream.h>
#include <chromeos/streams/stream_utils.h>

namespace {

chromeos::StreamPtr GetLEDDataStream(size_t index, bool write) {
  CHECK(index < LedStatus::num_leds);
  std::string led_path;
  if( index == 3 ) {
      led_path = "/sys/class/leds/boot/brightness";
  } else {
      led_path = base::StringPrintf("/sys/class/leds/led%" PRIuS "/brightness",
                                    index + 1);
  }
  base::FilePath dev_path{led_path};
  auto access_mode = chromeos::stream_utils::MakeAccessMode(!write, write);
  return chromeos::FileStream::Open(
      dev_path, access_mode, chromeos::FileStream::Disposition::OPEN_EXISTING,
      nullptr);
}

}  // anonymous namespace

std::vector<bool> LedStatus::GetStatus() const {
  std::vector<bool> leds(num_leds);
  for (size_t index = 0; index < num_leds; index++)
    leds[index] = IsLedOn(index);
  return leds;
}

bool LedStatus::IsLedOn(size_t index) const {
  chromeos::StreamPtr stream = GetLEDDataStream(index, false);
  if (!stream)
    return false;

  char buffer[10];
  size_t size_read = 0;
  if (!stream->ReadNonBlocking(buffer, sizeof(buffer), &size_read, nullptr,
                               nullptr)) {
    return false;
  }

  std::string value{buffer, size_read};
  base::TrimWhitespaceASCII(value, base::TrimPositions::TRIM_ALL, &value);
  int brightness = 0;
  if (!base::StringToInt(value, &brightness))
    return false;
  return brightness > 0;
}

void LedStatus::SetLedStatus(size_t index, bool on) {
  chromeos::StreamPtr stream = GetLEDDataStream(index, true);
  if (!stream)
    return;

  std::string brightness = on ? "255" : "0";
  stream->WriteAllBlocking(brightness.data(), brightness.size(), nullptr);
}