Merge "ziparchive: Allow ExtractEntryToFile() to work with block device."

 * Uncompress and write an entry to an open file identified by |fd|.

 * |entry->uncompressed_length| bytes will be written to the file at

 * its current offset, and the file will be truncated at the end of

 * the uncompressed data.

 * the uncompressed data (no truncation if |fd| references a block

 * device).

 *

 * Returns 0 on success and negative values on failure.

 */

  // Creates a FileWriter for |fd| and prepare to write |entry| to it,

  // guaranteeing that the file descriptor is valid and that there's enough

  // space on the volume to write out the entry completely and that the file

  // is truncated to the correct length.

  // is truncated to the correct length (no truncation if |fd| references a

  // block device).

  //

  // Returns a valid FileWriter on success, |nullptr| if an error occurred.

  static std::unique_ptr<FileWriter> Create(int fd, const ZipEntry* entry) {

    }

#endif  // __linux__

    struct stat sb;

    if (fstat(fd, &sb) == -1) {

      ALOGW("Zip: unable to fstat file: %s", strerror(errno));

      return std::unique_ptr<FileWriter>(nullptr);

    }

    // Block device doesn't support ftruncate(2).

    if (!S_ISBLK(sb.st_mode)) {

      result = TEMP_FAILURE_RETRY(ftruncate(fd, declared_length + current_offset));

      if (result == -1) {

        ALOGW("Zip: unable to truncate file to %" PRId64 ": %s",

              static_cast<int64_t>(declared_length + current_offset), strerror(errno));

        return std::unique_ptr<FileWriter>(nullptr);

      }

    }

    return std::unique_ptr<FileWriter>(new FileWriter(fd, declared_length));

  }