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Source code for mmcv.utils.misc

# Copyright (c) OpenMMLab. All rights reserved.
import collections.abc
import functools
import itertools
import subprocess
import warnings
from collections import abc
from importlib import import_module
from inspect import getfullargspec
from itertools import repeat


# From PyTorch internals
def _ntuple(n):

    def parse(x):
        if isinstance(x, collections.abc.Iterable):
            return x
        return tuple(repeat(x, n))

    return parse


to_1tuple = _ntuple(1)
to_2tuple = _ntuple(2)
to_3tuple = _ntuple(3)
to_4tuple = _ntuple(4)
to_ntuple = _ntuple


[docs]def is_str(x): """Whether the input is an string instance. Note: This method is deprecated since python 2 is no longer supported. """ return isinstance(x, str)
[docs]def import_modules_from_strings(imports, allow_failed_imports=False): """Import modules from the given list of strings. Args: imports (list | str | None): The given module names to be imported. allow_failed_imports (bool): If True, the failed imports will return None. Otherwise, an ImportError is raise. Default: False. Returns: list[module] | module | None: The imported modules. Examples: >>> osp, sys = import_modules_from_strings( ... ['os.path', 'sys']) >>> import os.path as osp_ >>> import sys as sys_ >>> assert osp == osp_ >>> assert sys == sys_ """ if not imports: return single_import = False if isinstance(imports, str): single_import = True imports = [imports] if not isinstance(imports, list): raise TypeError( f'custom_imports must be a list but got type {type(imports)}') imported = [] for imp in imports: if not isinstance(imp, str): raise TypeError( f'{imp} is of type {type(imp)} and cannot be imported.') try: imported_tmp = import_module(imp) except ImportError: if allow_failed_imports: warnings.warn(f'{imp} failed to import and is ignored.', UserWarning) imported_tmp = None else: raise ImportError imported.append(imported_tmp) if single_import: imported = imported[0] return imported
[docs]def iter_cast(inputs, dst_type, return_type=None): """Cast elements of an iterable object into some type. Args: inputs (Iterable): The input object. dst_type (type): Destination type. return_type (type, optional): If specified, the output object will be converted to this type, otherwise an iterator. Returns: iterator or specified type: The converted object. """ if not isinstance(inputs, abc.Iterable): raise TypeError('inputs must be an iterable object') if not isinstance(dst_type, type): raise TypeError('"dst_type" must be a valid type') out_iterable = map(dst_type, inputs) if return_type is None: return out_iterable else: return return_type(out_iterable)
[docs]def list_cast(inputs, dst_type): """Cast elements of an iterable object into a list of some type. A partial method of :func:`iter_cast`. """ return iter_cast(inputs, dst_type, return_type=list)
[docs]def tuple_cast(inputs, dst_type): """Cast elements of an iterable object into a tuple of some type. A partial method of :func:`iter_cast`. """ return iter_cast(inputs, dst_type, return_type=tuple)
[docs]def is_seq_of(seq, expected_type, seq_type=None): """Check whether it is a sequence of some type. Args: seq (Sequence): The sequence to be checked. expected_type (type): Expected type of sequence items. seq_type (type, optional): Expected sequence type. Returns: bool: Whether the sequence is valid. """ if seq_type is None: exp_seq_type = abc.Sequence else: assert isinstance(seq_type, type) exp_seq_type = seq_type if not isinstance(seq, exp_seq_type): return False for item in seq: if not isinstance(item, expected_type): return False return True
[docs]def is_list_of(seq, expected_type): """Check whether it is a list of some type. A partial method of :func:`is_seq_of`. """ return is_seq_of(seq, expected_type, seq_type=list)
[docs]def is_tuple_of(seq, expected_type): """Check whether it is a tuple of some type. A partial method of :func:`is_seq_of`. """ return is_seq_of(seq, expected_type, seq_type=tuple)
[docs]def slice_list(in_list, lens): """Slice a list into several sub lists by a list of given length. Args: in_list (list): The list to be sliced. lens(int or list): The expected length of each out list. Returns: list: A list of sliced list. """ if isinstance(lens, int): assert len(in_list) % lens == 0 lens = [lens] * int(len(in_list) / lens) if not isinstance(lens, list): raise TypeError('"indices" must be an integer or a list of integers') elif sum(lens) != len(in_list): raise ValueError('sum of lens and list length does not ' f'match: {sum(lens)} != {len(in_list)}') out_list = [] idx = 0 for i in range(len(lens)): out_list.append(in_list[idx:idx + lens[i]]) idx += lens[i] return out_list
[docs]def concat_list(in_list): """Concatenate a list of list into a single list. Args: in_list (list): The list of list to be merged. Returns: list: The concatenated flat list. """ return list(itertools.chain(*in_list))
[docs]def check_prerequisites( prerequisites, checker, msg_tmpl='Prerequisites "{}" are required in method "{}" but not ' 'found, please install them first.'): # yapf: disable """A decorator factory to check if prerequisites are satisfied. Args: prerequisites (str of list[str]): Prerequisites to be checked. checker (callable): The checker method that returns True if a prerequisite is meet, False otherwise. msg_tmpl (str): The message template with two variables. Returns: decorator: A specific decorator. """ def wrap(func): @functools.wraps(func) def wrapped_func(*args, **kwargs): requirements = [prerequisites] if isinstance( prerequisites, str) else prerequisites missing = [] for item in requirements: if not checker(item): missing.append(item) if missing: print(msg_tmpl.format(', '.join(missing), func.__name__)) raise RuntimeError('Prerequisites not meet.') else: return func(*args, **kwargs) return wrapped_func return wrap
def _check_py_package(package): try: import_module(package) except ImportError: return False else: return True def _check_executable(cmd): if subprocess.call(f'which {cmd}', shell=True) != 0: return False else: return True
[docs]def requires_package(prerequisites): """A decorator to check if some python packages are installed. Example: >>> @requires_package('numpy') >>> func(arg1, args): >>> return numpy.zeros(1) array([0.]) >>> @requires_package(['numpy', 'non_package']) >>> func(arg1, args): >>> return numpy.zeros(1) ImportError """ return check_prerequisites(prerequisites, checker=_check_py_package)
[docs]def requires_executable(prerequisites): """A decorator to check if some executable files are installed. Example: >>> @requires_executable('ffmpeg') >>> func(arg1, args): >>> print(1) 1 """ return check_prerequisites(prerequisites, checker=_check_executable)
[docs]def deprecated_api_warning(name_dict, cls_name=None): """A decorator to check if some arguments are deprecate and try to replace deprecate src_arg_name to dst_arg_name. Args: name_dict(dict): key (str): Deprecate argument names. val (str): Expected argument names. Returns: func: New function. """ def api_warning_wrapper(old_func): @functools.wraps(old_func) def new_func(*args, **kwargs): # get the arg spec of the decorated method args_info = getfullargspec(old_func) # get name of the function func_name = old_func.__name__ if cls_name is not None: func_name = f'{cls_name}.{func_name}' if args: arg_names = args_info.args[:len(args)] for src_arg_name, dst_arg_name in name_dict.items(): if src_arg_name in arg_names: warnings.warn( f'"{src_arg_name}" is deprecated in ' f'`{func_name}`, please use "{dst_arg_name}" ' 'instead', DeprecationWarning) arg_names[arg_names.index(src_arg_name)] = dst_arg_name if kwargs: for src_arg_name, dst_arg_name in name_dict.items(): if src_arg_name in kwargs: assert dst_arg_name not in kwargs, ( f'The expected behavior is to replace ' f'the deprecated key `{src_arg_name}` to ' f'new key `{dst_arg_name}`, but got them ' f'in the arguments at the same time, which ' f'is confusing. `{src_arg_name} will be ' f'deprecated in the future, please ' f'use `{dst_arg_name}` instead.') warnings.warn( f'"{src_arg_name}" is deprecated in ' f'`{func_name}`, please use "{dst_arg_name}" ' 'instead', DeprecationWarning) kwargs[dst_arg_name] = kwargs.pop(src_arg_name) # apply converted arguments to the decorated method output = old_func(*args, **kwargs) return output return new_func return api_warning_wrapper
[docs]def is_method_overridden(method, base_class, derived_class): """Check if a method of base class is overridden in derived class. Args: method (str): the method name to check. base_class (type): the class of the base class. derived_class (type | Any): the class or instance of the derived class. """ assert isinstance(base_class, type), \ "base_class doesn't accept instance, Please pass class instead." if not isinstance(derived_class, type): derived_class = derived_class.__class__ base_method = getattr(base_class, method) derived_method = getattr(derived_class, method) return derived_method != base_method
[docs]def has_method(obj: object, method: str) -> bool: """Check whether the object has a method. Args: method (str): The method name to check. obj (object): The object to check. Returns: bool: True if the object has the method else False. """ return hasattr(obj, method) and callable(getattr(obj, method))
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