#
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# (C) Copyright 2015 Enthought, Inc., Austin, TX
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# All right reserved.
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#
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# This file is open source software distributed according to the terms in
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# LICENSE.txt
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#
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""" Utility functions to help with cffi wrapping.
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"""
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from __future__ import absolute_import
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from win32ctypes.core.compat import is_bytes, is_integer, text_type
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from cffi import FFI
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ffi = FFI()
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ffi.set_unicode(True)
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def HMODULE(cdata):
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return int(ffi.cast("intptr_t", cdata))
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def PVOID(x):
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return ffi.cast("void *", x)
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def IS_INTRESOURCE(x):
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""" Check if x is an index into the id list.
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"""
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return int(ffi.cast("uintptr_t", x)) >> 16 == 0
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def RESOURCE(resource):
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""" Convert a resource into a compatible input for cffi.
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"""
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if is_integer(resource):
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resource = ffi.cast('wchar_t *', resource)
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elif is_bytes(resource):
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resource = text_type(resource)
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return resource
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def resource(lpRESOURCEID):
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""" Convert the windows RESOURCE into a python friendly object.
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"""
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if IS_INTRESOURCE(lpRESOURCEID):
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resource = int(ffi.cast("uintptr_t", lpRESOURCEID))
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else:
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resource = ffi.string(lpRESOURCEID)
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return resource
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class ErrorWhen(object):
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""" Callable factory for raising errors when calling cffi functions.
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"""
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def __init__(self, check, raise_on_zero=True):
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""" Constructor
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Parameters
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----------
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check :
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The return value that designates that an error has taken place.
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raise_on_zero : bool
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When set any error will be raised. When false the winerror
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is checked and only non-zero win errors are raised. Currently
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this parameters is used to workaround issues with the win32
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implementation in ``wine``.
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"""
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self._check = check
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self._raise_on_zero = raise_on_zero
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def __call__(self, value, function_name=''):
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if value == self._check:
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self._raise_error(function_name)
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else:
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return value
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def _raise_error(self, function_name=''):
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code, message = ffi.getwinerror()
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exception = WindowsError()
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exception.errno = ffi.errno
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exception.winerror = code
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exception.strerror = message
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exception.function = function_name
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raise exception
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check_null = ErrorWhen(ffi.NULL)
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check_zero = ErrorWhen(0)
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check_false = ErrorWhen(False)
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class Libraries(object):
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def __getattr__(self, name):
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library = ffi.dlopen('{}.dll'.format(name))
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self.__dict__[name] = library
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return library
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dlls = Libraries()
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