import types
import gzip
import textwrap
import os
from functools import wraps
[docs]
def open_and_close(func):
"""Decorator for all parsing functions that originally got a file name and
went thru the whole file b/c the things that they search can occur in
arbitrary order.
These functions did
* open the file
* go thru
* close file
Now, they all expect file objects, as first argument. This decorator
assures that the first arg to `func` is a file object.
Cases:
* 1st arg is a fileobject: do nothig, just call function
* 1st arg is a file name:
* open file
* call func
* close file
Examples
--------
>>> @open_and_close
>>> def file_txt_content(fh):
... # fh is a file object
... return fh.read()
>>> fh = open('my_file.txt')
>>> print(file_txt_content(fh))
>>> fh.close()
>>>
>>> print(file_txt_content('my_file.txt'))
"""
@wraps(func)
def wrapper(*args, **kwargs):
largs = list(args)
if isinstance(largs[0], str):
# Filename case.
fn = largs[0]
if fn.endswith('.gz'):
_open = gzip.open
else:
_open = open
fd = _open(fn, 'r')
# Files opened with gzip don't have a 'name' attr.
if not hasattr(fd, 'name'):
fd.name = os.path.abspath(os.path.expanduser(fn))
largs[0] = fd
ret = func(*tuple(largs), **kwargs)
largs[0].close()
return ret
else:
# File object case. Don't explicitly test for types.FileType b/c
# that does not if largs[0] is actually a [c]StringIO.StringIO
# instances.
#
# Also, the 'name' attribute can be set (largs[0].name = ...) for
# StringIO.StringIO, but NOT for cStringIO.StringIO. We don't even
# try fiddling with try-except here. There just won't be any
# filename.
return func(*args, **kwargs)
return wrapper
[docs]
def crys_add_doc(func):
"""Decorator to add common docstrings to functions with crystal/unit cell
related functionallity."""
dct = {}
dct['cell_doc'] = \
"""cell : array, shape (3,3)
Matrix with basis vectors as rows."""
dct['cryst_const_doc'] = \
"""cryst_const : array_like, shape (6,)
[a, b, c, alpha, beta, gamma], where alpha=angle(b,c), beta=angle(a,c),
gamma=angle(a,b)"""
dct['celldm'] = \
"""celldm : array_like, shape (6,)
[a, b/a, c/a, cos(alpha), cos(beta), cos(gamma)]
`a` is supposed to be in Bohr"""
dct['notes_cell_crys_const'] = \
"""We use PWscf notation. CELL_PARAMETERS == (matrix of) primitime basis
vectors elsewhere crystallographic constants a,b,c,alpha,beta,gamma == cell
parameters elsewhere"""
# Use dictionary string replacement:
# >>> '%(lala)i %(xxx)s' %{'lala': 3, 'xxx': 'grrr'}
# '3 grrr'
func.__doc__ = func.__doc__ % dct
return func
# NOTE: can be drop-in replaced by functools.cached_property() as of Python 3.8
[docs]
class lazyprop:
"""Decorator for creating lazy evaluated properties.
The property should represent non-mutable data, as it replaces itself.
kudos: Cyclone over at stackoverflow!
http://stackoverflow.com/questions/3012421/python-lazy-property-decorator
"""
[docs]
def __init__(self,fget):
self.fget = fget
self.__name__ = fget.__name__
def __get__(self,obj,cls):
if obj is None:
return None
value = self.fget(obj)
setattr(obj,self.__name__,value)
return value
# http://stackoverflow.com/questions/3012421/python-lazy-property-decorator
##def lazyprop(fn):
## attr_name = '_lazy_' + fn.__name__
## @property
## def _lazyprop(self):
## if not hasattr(self, attr_name):
## setattr(self, attr_name, fn(self))
## return getattr(self, attr_name)
## return _lazyprop
