85 lines
2.6 KiB
Python
85 lines
2.6 KiB
Python
"""Tools for loading Python modules from arbitrary locations.
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"""
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import imp
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import os
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import sys
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# todo seems to be only used by dogstream at this point, possibly remove?
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def imp_type_for_filename(filename):
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"""Given the name of a Python module, return a type description suitable to be passed to imp.load_module().
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"""
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for type_data in imp.get_suffixes():
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extension = type_data[0]
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if filename.endswith(extension):
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return type_data
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return None
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def load_qualified_module(full_module_name, path=None):
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"""Load a module which may be within a package.
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"""
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remaining_pieces = full_module_name.split('.')
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done_pieces = []
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file_obj = None
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while remaining_pieces:
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try:
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done_pieces.append(remaining_pieces.pop(0))
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curr_module_name = '.'.join(done_pieces)
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(file_obj, filename, description) = imp.find_module(done_pieces[-1], path)
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package_module = imp.load_module(curr_module_name, file_obj, filename, description)
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path = getattr(package_module, '__path__', None) or [filename]
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finally:
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if file_obj:
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file_obj.close()
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return package_module
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def module_name_for_filename(filename):
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"""Given the name of a Python file, find an appropropriate module name.
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This involves determining whether the file is within a package, and
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determining the name of same.
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"""
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all_segments = filename.split(os.sep)
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path_elements = all_segments[:-1]
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module_elements = [all_segments[-1].rsplit('.', 1)[0]]
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while os.path.exists('/'.join(path_elements + ['__init__.py'])):
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module_elements.insert(0, path_elements.pop())
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modulename = '.'.join(module_elements)
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basename = '/'.join(path_elements)
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return basename, modulename
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def get_module(name):
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"""Given either an absolute path to a Python file or a module name, load and return a Python module.
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If the module is already loaded, takes no action.
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"""
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if name.startswith('/'):
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basename, modulename = module_name_for_filename(name)
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path = [basename]
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else:
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modulename = name
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path = None
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if modulename in sys.modules:
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return sys.modules[modulename]
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return load_qualified_module(modulename, path)
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def load(config_string, default_name=None):
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"""Given a module name and an object expected to be contained within, return said object.
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"""
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(module_name, object_name) = (config_string.rsplit(':', 1) + [default_name])[:2]
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module = get_module(module_name)
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if object_name:
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return getattr(module, object_name)
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else:
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return module
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