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1 """functools.py - Tools for working with functions and callable objects |
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2 """ |
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3 # Python module wrapper for _functools C module |
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4 # to allow utilities written in Python to be added |
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5 # to the functools module. |
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6 # Written by Nick Coghlan <ncoghlan at gmail.com> |
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7 # Copyright (C) 2006 Python Software Foundation. |
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8 # See C source code for _functools credits/copyright |
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9 |
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10 from _functools import partial, reduce |
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11 |
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12 # update_wrapper() and wraps() are tools to help write |
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13 # wrapper functions that can handle naive introspection |
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14 |
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15 WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__') |
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16 WRAPPER_UPDATES = ('__dict__',) |
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17 def update_wrapper(wrapper, |
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18 wrapped, |
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19 assigned = WRAPPER_ASSIGNMENTS, |
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20 updated = WRAPPER_UPDATES): |
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21 """Update a wrapper function to look like the wrapped function |
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22 |
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23 wrapper is the function to be updated |
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24 wrapped is the original function |
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25 assigned is a tuple naming the attributes assigned directly |
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26 from the wrapped function to the wrapper function (defaults to |
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27 functools.WRAPPER_ASSIGNMENTS) |
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28 updated is a tuple naming the attributes of the wrapper that |
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29 are updated with the corresponding attribute from the wrapped |
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30 function (defaults to functools.WRAPPER_UPDATES) |
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31 """ |
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32 for attr in assigned: |
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33 setattr(wrapper, attr, getattr(wrapped, attr)) |
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34 for attr in updated: |
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35 getattr(wrapper, attr).update(getattr(wrapped, attr, {})) |
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36 # Return the wrapper so this can be used as a decorator via partial() |
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37 return wrapper |
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38 |
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39 def wraps(wrapped, |
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40 assigned = WRAPPER_ASSIGNMENTS, |
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41 updated = WRAPPER_UPDATES): |
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42 """Decorator factory to apply update_wrapper() to a wrapper function |
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43 |
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44 Returns a decorator that invokes update_wrapper() with the decorated |
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45 function as the wrapper argument and the arguments to wraps() as the |
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46 remaining arguments. Default arguments are as for update_wrapper(). |
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47 This is a convenience function to simplify applying partial() to |
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48 update_wrapper(). |
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49 """ |
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50 return partial(update_wrapper, wrapped=wrapped, |
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51 assigned=assigned, updated=updated) |