64 lines
2.2 KiB
Python
64 lines
2.2 KiB
Python
# Copyright (c) 2015,2018,2019 MetPy Developers.
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# Distributed under the terms of the BSD 3-Clause License.
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# SPDX-License-Identifier: BSD-3-Clause
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"""Collection of tools for managing the package."""
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# Used to specify functions that should be exported--i.e. added to __all__
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# Inspired by David Beazley and taken from python-ideas:
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# https://mail.python.org/pipermail/python-ideas/2014-May/027824.html
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__all__ = ("Exporter",)
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class Exporter:
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"""Manages exporting of symbols from the module.
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Grabs a reference to `globals()` for a module and provides a decorator to add
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functions and classes to `__all__` rather than requiring a separately maintained list.
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Also provides a context manager to do this for instances by adding all instances added
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within a block to `__all__`.
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"""
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def __init__(self, globls):
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"""Initialize the Exporter."""
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self.globls = globls
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self.exports = globls.setdefault("__all__", [])
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def export(self, defn):
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"""Declare a function or class as exported."""
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self.exports.append(defn.__name__)
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return defn
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def __enter__(self):
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"""Start a block tracking all instances created at global scope."""
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# pylint: disable=attribute-defined-outside-init
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self.start_vars = set(self.globls)
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# pylint: enable=attribute-defined-outside-init
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def __exit__(self, exc_type, exc_val, exc_tb):
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"""Exit the instance tracking block."""
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self.exports.extend(set(self.globls) - self.start_vars)
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del self.start_vars
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def set_module(globls):
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"""Set the module for all functions in ``__all__``.
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This sets the ``__module__`` attribute of all items within the ``__all__`` list
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for the calling module.
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This supports our hoisting of functions out of individual modules, which are
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considered implementation details, into the namespace of the top-level subpackage.
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Parameters
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----------
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globls : Dict[str, object]
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Mapping of all global variables for the module. This contains all needed
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python special ("dunder") variables needed to be modified.
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"""
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for item in globls["__all__"]:
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obj = globls[item]
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if hasattr(obj, "__module__"):
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obj.__module__ = globls["__name__"]
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