cosmos_predict1/utils/easy_io/backends/base_backend.py

# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
#
# 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.

import os
import os.path as osp
from abc import ABCMeta, abstractmethod


def mkdir_or_exist(dir_name, mode=0o777):
    if dir_name == "":
        return
    dir_name = osp.expanduser(dir_name)
    os.makedirs(dir_name, mode=mode, exist_ok=True)


def has_method(obj, method):
    return hasattr(obj, method) and callable(getattr(obj, method))


class BaseStorageBackend(metaclass=ABCMeta):
    """Abstract class of storage backends.

    All backends need to implement two apis: :meth:`get()` and
    :meth:`get_text()`.

    - :meth:`get()` reads the file as a byte stream.
    - :meth:`get_text()` reads the file as texts.
    """

    # a flag to indicate whether the backend can create a symlink for a file
    # This attribute will be deprecated in future.
    _allow_symlink = False

    @property
    def allow_symlink(self):
        return self._allow_symlink

    @property
    def name(self):
        return self.__class__.__name__

    @abstractmethod
    def get(self, filepath):
        pass

    @abstractmethod
    def get_text(self, filepath):
        pass