# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)
"""Implementation of Spack imports that uses importlib underneath.
``importlib`` is only fully implemented in Python 3.
"""
from importlib.machinery import SourceFileLoader # novm
[docs]class PrependFileLoader(SourceFileLoader):
def __init__(self, full_name, path, prepend=None):
super(PrependFileLoader, self).__init__(full_name, path)
self.prepend = prepend
[docs] def path_stats(self, path):
stats = super(PrependFileLoader, self).path_stats(path)
if self.prepend:
stats["size"] += len(self.prepend) + 1
return stats
[docs] def get_data(self, path):
data = super(PrependFileLoader, self).get_data(path)
if path != self.path or self.prepend is None:
return data
else:
return self.prepend.encode() + b"\n" + data
[docs]def load_source(full_name, path, prepend=None):
"""Import a Python module from source.
Load the source file and add it to ``sys.modules``.
Args:
full_name (str): full name of the module to be loaded
path (str): path to the file that should be loaded
prepend (str or None): some optional code to prepend to the
loaded module; e.g., can be used to inject import statements
Returns:
the loaded module
"""
# use our custom loader
loader = PrependFileLoader(full_name, path, prepend)
return loader.load_module()