winlitecom.py

   1 #Copyright (c) 2009 Vincent Povirk
   2 #
   3 #Permission is hereby granted, free of charge, to any person
   4 #obtaining a copy of this software and associated documentation
   5 #files (the "Software"), to deal in the Software without
   6 #restriction, including without limitation the rights to use,
   7 #copy, modify, merge, publish, distribute, sublicense, and/or sell
   8 #copies of the Software, and to permit persons to whom the
   9 #Software is furnished to do so, subject to the following
  10 #conditions:
  11 #
  12 #The above copyright notice and this permission notice shall be
  13 #included in all copies or substantial portions of the Software.
  14 #
  15 #THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16 #EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  17 #OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18 #NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  19 #HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  20 #WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21 #FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22 #OTHER DEALINGS IN THE SOFTWARE.
  23
  24 # basic COM utilities
  25
  26 from ctypes import POINTER, c_void_p, Structure, WINFUNCTYPE, cast, byref, addressof
  27 from windef import HRESULT, GUID, REFIID, ULONG
  28
  29 class _COMMethod(object):
  30     __slots__ = ['p', 'name']
  31     def __init__(self, obj, name):
  32         self.p = obj.p
  33         self.name = name
  34
  35     def __call__(self, *args):
  36         return getattr(self.p.contents.contents, self.name)(self.p, *args)
  37
  38 class _COMMethodGetter(object):
  39     __slots__ = ['name']
  40     def __init__(self, name):
  41         self.name = name
  42
  43     def __get__(self, instance, owner):
  44         return _COMMethod(instance, self.name)
  45
  46 def _translate_methods(methods, vtable):
  47     # translates a com method list into a vtable
  48     result = []
  49     objtype = POINTER(POINTER(vtable))
  50     for method in methods:
  51         name = method[0]
  52         functype = WINFUNCTYPE(method[1], objtype, *method[2:])
  53         result.append((name, functype))
  54     return result
  55
  56 class _interface_outparam(object):
  57     __slots__ = ['p', '_as_parameter_']
  58     def __init__(self):
  59         self.p = c_void_p(0)
  60         self._as_parameter_ = addressof(self.p)
  61
  62     @classmethod
  63     def from_param(cls, arg):
  64         if arg == None:
  65             return c_void_p(0)
  66         elif isinstance(arg, cls) or (isinstance(arg, _interface_outparam) and issubclass(cls.cls, arg.cls)):
  67             return arg
  68         else:
  69             raise TypeError
  70
  71     def get(self):
  72         if self.p.value:
  73             result = self.cls(self.p.value)
  74             self.p.value = None
  75             return result
  76         else:
  77             raise ValueError("NULL interface pointer")
  78
  79     def __del__(self):
  80         if self.p.value:
  81             self.get()
  82
  83 class _InterfaceClass(type):
  84     def __init__(self, name, bases, dict):
  85         type.__init__(self, name, bases, dict)
  86
  87         # create the vtable type
  88         class vtable(Structure):
  89             pass
  90         vtable.__name__ = '_%s_vtable' % name
  91         self._vtable = vtable
  92
  93         if 'com_methods' in dict:
  94             self.set_methods(self.com_methods)
  95         #else the creator of the class must call set_methods
  96
  97         # a COM object is a pointer to a pointer to a vtable
  98         self.objtype = POINTER(POINTER(vtable))
  99
 100         self.outparam = type('_%s_outparam' % name, (_interface_outparam,), {'cls': self})
 101
 102     def set_methods(self, methods):
 103         # add the base class methods to our list of methods
 104         for base in self.__bases__:
 105             try:
 106                 self.com_methods = base.com_methods + methods
 107                 break
 108             except AttributeError:
 109                 pass
 110         else:
 111             self.com_methods = methods
 112
 113         self._vtable._fields_ = _translate_methods(self.com_methods, self._vtable)
 114
 115         # add an attribute for each method
 116         for method in self.com_methods:
 117             setattr(self, method[0], _COMMethodGetter(method[0]))
 118
 119 class _BaseInterface(object):
 120     com_methods = []
 121
 122     def __init__(self, p):
 123         self.p = cast(c_void_p(p), self.objtype)
 124
 125     def _get_parameter(self):
 126         return self.p
 127
 128     _as_parameter_ = property(_get_parameter)
 129
 130     @classmethod
 131     def from_param(cls, arg):
 132         if arg is None:
 133             return c_void_p(0)
 134         elif isinstance(arg, cls):
 135             return arg
 136         else:
 137             raise TypeError
 138
 139 # Needed because 3.0 added new syntax for metaclasses and removed the old syntax.
 140 _InterfaceClassInstanceBase = _InterfaceClass('_InterfaceClassInstanceBase', (_BaseInterface,), {})
 141
 142 class IUnknown(_InterfaceClassInstanceBase):
 143     com_methods = [
 144         ('QueryInterface', HRESULT, REFIID, POINTER(c_void_p)),
 145         ('AddRef', ULONG),
 146         ('Release', ULONG),
 147         ]
 148
 149     iid = GUID("00000000-0000-0000-C000-000000000046")
 150
 151     def __init__(self, obj):
 152         try:
 153             p = c_void_p()
 154             obj.QueryInterface(byref(self.iid), byref(p))
 155             self.p = cast(p, self.objtype)
 156         except AttributeError:
 157             _InterfaceClassInstanceBase.__init__(self, obj)
 158
 159     def __del__(self):
 160         self.Release()
 161