text: # Copyright 2020 Huawei Technologies Co., Ltd
  #
  # 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.
  # ============================================================================
  """Writes events to disk in a logdir."""
  import os
  import stat
  from shutil import disk_usage
  
  from ..._c_expression import EventWriter_
  from ._summary_adapter import package_init_event
  
  
  class BaseWriter:
      """BaseWriter to be subclass."""
  
      def __init__(self, filepath, max_file_size=None) -> None:
          self._filepath, self._max_file_size = filepath, max_file_size
          self._writer: EventWriter_ = None
  
      def init_writer(self):
          """Write some metadata etc."""
  
      @property
      def writer(self) -> EventWriter_:
          """Get the writer."""
          if self._writer is not None:
              return self._writer
  
          with open(self._filepath, 'w'):
              os.chmod(self._filepath, stat.S_IWUSR | stat.S_IRUSR)
          self._writer = EventWriter_(self._filepath)
          self.init_writer()
          return self._writer
  
      def write(self, plugin, data):
          """Write data to file."""
          if self.writer and disk_usage(self._filepath).free < len(data) * 32:
              raise RuntimeError(f"The disk space may be soon exhausted by the '{self._filepath}'.")
          # 8: data length
          # 4: crc32 of data length
          # 4: crc32 of data
          metadata_length = 8 + 4 + 4
          required_length = len(data) + metadata_length
          if self._max_file_size is None:
              self.writer.Write(data)
          elif self._max_file_size >= required_length:
              self._max_file_size -= required_length
              self.writer.Write(data)
          else:
              raise RuntimeError(f"'max_file_size' reached: There are {self._max_file_size} bytes remaining, "
                                 f"but the '{self._filepath}' requires to write {required_length} bytes.")
  
      def flush(self):
          """Flush the writer."""
          if self._writer is not None:
              self._writer.Flush()
  
      def close(self):
          """Close the writer."""
          if self._writer is not None:
              self._writer.Shut()
  
  
  class SummaryWriter(BaseWriter):
      """SummaryWriter for write summaries."""
  
      def init_writer(self):
          """Write some metadata etc."""
          self.writer.Write(package_init_event().SerializeToString())
  
      def write(self, plugin, data):
          """Write data to file."""
          if plugin in ('summary', 'graph'):
              super().write(plugin, data)
  
  
  class LineageWriter(BaseWriter):
      """LineageWriter for write lineage."""
  
      def write(self, plugin, data):
          """Write data to file."""
          if plugin in ('dataset_graph', 'train_lineage', 'eval_lineage', 'custom_lineage_data'):
              super().write(plugin, data)
  