text: //
  // Copyright (C) 2009 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 "update_engine/payload_consumer/file_writer.h"
  
  #include <errno.h>
  
  namespace chromeos_update_engine {
  
  int DirectFileWriter::Open(const char* path, int flags, mode_t mode) {
    CHECK_EQ(fd_, -1);
    fd_ = open(path, flags, mode);
    if (fd_ < 0)
      return -errno;
    return 0;
  }
  
  bool DirectFileWriter::Write(const void* bytes, size_t count) {
    CHECK_GE(fd_, 0);
    const char* char_bytes = reinterpret_cast<const char*>(bytes);
  
    size_t bytes_written = 0;
    while (bytes_written < count) {
      ssize_t rc = write(fd_, char_bytes + bytes_written,
                         count - bytes_written);
      if (rc < 0)
        return false;
      bytes_written += rc;
    }
    CHECK_EQ(bytes_written, count);
    return bytes_written == count;
  }
  
  int DirectFileWriter::Close() {
    CHECK_GE(fd_, 0);
    int rc = close(fd_);
  
    // This can be any negative number that's not -1. This way, this FileWriter
    // won't be used again for another file.
    fd_ = -2;
  
    if (rc < 0)
      return -errno;
    return rc;
  }
  
  }  // namespace chromeos_update_engine
  