codekingpro/portable-devtools

1# Copyright 2016 Google Inc. All rights reserved.2#3# Licensed under the Apache License, Version 2.0 (the "License");4# you may not use this file except in compliance with the License.5# You may obtain a copy of the License at6#7#     http://www.apache.org/licenses/LICENSE-2.08#9# Unless required by applicable law or agreed to in writing, software10# distributed under the License is distributed on an "AS IS" BASIS,11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.12# See the License for the specific language governing permissions and13# limitations under the License.14 15"""A tiny version of `six` to help with backwards compability.16 17Also includes compatibility helpers for numpy.18"""19 20import sys21 22PY2 = sys.version_info[0] == 223PY26 = sys.version_info[0:2] == (2, 6)24PY27 = sys.version_info[0:2] == (2, 7)25PY275 = sys.version_info[0:3] >= (2, 7, 5)26PY3 = sys.version_info[0] == 327PY34 = sys.version_info[0:2] >= (3, 4)28 29if PY3:30  import importlib.machinery31 32  string_types = (str,)33  binary_types = (bytes, bytearray)34  range_func = range35  memoryview_type = memoryview36  struct_bool_decl = "?"37else:38  import imp39 40  string_types = (unicode,)41  if PY26 or PY27:42    binary_types = (str, bytearray)43  else:44    binary_types = (str,)45  range_func = xrange46  if PY26 or (PY27 and not PY275):47    memoryview_type = buffer48    struct_bool_decl = "<b"49  else:50    memoryview_type = memoryview51    struct_bool_decl = "?"52 53# Helper functions to facilitate making numpy optional instead of required54 55 56def import_numpy():57  """Returns the numpy module if it exists on the system,58 59  otherwise returns None.60  """61  if PY3:62    numpy_exists = importlib.machinery.PathFinder.find_spec("numpy") is not None63  else:64    try:65      imp.find_module("numpy")66      numpy_exists = True67    except ImportError:68      numpy_exists = False69 70  if numpy_exists:71    # We do this outside of try/except block in case numpy exists72    # but is not installed correctly. We do not want to catch an73    # incorrect installation which would manifest as an74    # ImportError.75    import numpy as np76  else:77    np = None78 79  return np80 81 82class NumpyRequiredForThisFeature(RuntimeError):83  """Error raised when user tries to use a feature that84 85  requires numpy without having numpy installed.86  """87 88  pass89 90 91# NOTE: Future Jython support may require code here (look at `six`).92