diff options
Diffstat (limited to 'cffi/backend_ctypes.py')
| -rw-r--r-- | cffi/backend_ctypes.py | 1121 |
1 files changed, 1121 insertions, 0 deletions
diff --git a/cffi/backend_ctypes.py b/cffi/backend_ctypes.py new file mode 100644 index 0000000..679ae05 --- /dev/null +++ b/cffi/backend_ctypes.py @@ -0,0 +1,1121 @@ +import ctypes, ctypes.util, operator, sys +from . import model + +if sys.version_info < (3,): + bytechr = chr +else: + unicode = str + long = int + xrange = range + bytechr = lambda num: bytes([num]) + +class CTypesType(type): + pass + +class CTypesData(object): + __metaclass__ = CTypesType + __slots__ = ['__weakref__'] + __name__ = '<cdata>' + + def __init__(self, *args): + raise TypeError("cannot instantiate %r" % (self.__class__,)) + + @classmethod + def _newp(cls, init): + raise TypeError("expected a pointer or array ctype, got '%s'" + % (cls._get_c_name(),)) + + @staticmethod + def _to_ctypes(value): + raise TypeError + + @classmethod + def _arg_to_ctypes(cls, *value): + try: + ctype = cls._ctype + except AttributeError: + raise TypeError("cannot create an instance of %r" % (cls,)) + if value: + res = cls._to_ctypes(*value) + if not isinstance(res, ctype): + res = cls._ctype(res) + else: + res = cls._ctype() + return res + + @classmethod + def _create_ctype_obj(cls, init): + if init is None: + return cls._arg_to_ctypes() + else: + return cls._arg_to_ctypes(init) + + @staticmethod + def _from_ctypes(ctypes_value): + raise TypeError + + @classmethod + def _get_c_name(cls, replace_with=''): + return cls._reftypename.replace(' &', replace_with) + + @classmethod + def _fix_class(cls): + cls.__name__ = 'CData<%s>' % (cls._get_c_name(),) + cls.__qualname__ = 'CData<%s>' % (cls._get_c_name(),) + cls.__module__ = 'ffi' + + def _get_own_repr(self): + raise NotImplementedError + + def _addr_repr(self, address): + if address == 0: + return 'NULL' + else: + if address < 0: + address += 1 << (8*ctypes.sizeof(ctypes.c_void_p)) + return '0x%x' % address + + def __repr__(self, c_name=None): + own = self._get_own_repr() + return '<cdata %r %s>' % (c_name or self._get_c_name(), own) + + def _convert_to_address(self, BClass): + if BClass is None: + raise TypeError("cannot convert %r to an address" % ( + self._get_c_name(),)) + else: + raise TypeError("cannot convert %r to %r" % ( + self._get_c_name(), BClass._get_c_name())) + + @classmethod + def _get_size(cls): + return ctypes.sizeof(cls._ctype) + + def _get_size_of_instance(self): + return ctypes.sizeof(self._ctype) + + @classmethod + def _cast_from(cls, source): + raise TypeError("cannot cast to %r" % (cls._get_c_name(),)) + + def _cast_to_integer(self): + return self._convert_to_address(None) + + @classmethod + def _alignment(cls): + return ctypes.alignment(cls._ctype) + + def __iter__(self): + raise TypeError("cdata %r does not support iteration" % ( + self._get_c_name()),) + + def _make_cmp(name): + cmpfunc = getattr(operator, name) + def cmp(self, other): + v_is_ptr = not isinstance(self, CTypesGenericPrimitive) + w_is_ptr = (isinstance(other, CTypesData) and + not isinstance(other, CTypesGenericPrimitive)) + if v_is_ptr and w_is_ptr: + return cmpfunc(self._convert_to_address(None), + other._convert_to_address(None)) + elif v_is_ptr or w_is_ptr: + return NotImplemented + else: + if isinstance(self, CTypesGenericPrimitive): + self = self._value + if isinstance(other, CTypesGenericPrimitive): + other = other._value + return cmpfunc(self, other) + cmp.func_name = name + return cmp + + __eq__ = _make_cmp('__eq__') + __ne__ = _make_cmp('__ne__') + __lt__ = _make_cmp('__lt__') + __le__ = _make_cmp('__le__') + __gt__ = _make_cmp('__gt__') + __ge__ = _make_cmp('__ge__') + + def __hash__(self): + return hash(self._convert_to_address(None)) + + def _to_string(self, maxlen): + raise TypeError("string(): %r" % (self,)) + + +class CTypesGenericPrimitive(CTypesData): + __slots__ = [] + + def __hash__(self): + return hash(self._value) + + def _get_own_repr(self): + return repr(self._from_ctypes(self._value)) + + +class CTypesGenericArray(CTypesData): + __slots__ = [] + + @classmethod + def _newp(cls, init): + return cls(init) + + def __iter__(self): + for i in xrange(len(self)): + yield self[i] + + def _get_own_repr(self): + return self._addr_repr(ctypes.addressof(self._blob)) + + +class CTypesGenericPtr(CTypesData): + __slots__ = ['_address', '_as_ctype_ptr'] + _automatic_casts = False + kind = "pointer" + + @classmethod + def _newp(cls, init): + return cls(init) + + @classmethod + def _cast_from(cls, source): + if source is None: + address = 0 + elif isinstance(source, CTypesData): + address = source._cast_to_integer() + elif isinstance(source, (int, long)): + address = source + else: + raise TypeError("bad type for cast to %r: %r" % + (cls, type(source).__name__)) + return cls._new_pointer_at(address) + + @classmethod + def _new_pointer_at(cls, address): + self = cls.__new__(cls) + self._address = address + self._as_ctype_ptr = ctypes.cast(address, cls._ctype) + return self + + def _get_own_repr(self): + try: + return self._addr_repr(self._address) + except AttributeError: + return '???' + + def _cast_to_integer(self): + return self._address + + def __nonzero__(self): + return bool(self._address) + __bool__ = __nonzero__ + + @classmethod + def _to_ctypes(cls, value): + if not isinstance(value, CTypesData): + raise TypeError("unexpected %s object" % type(value).__name__) + address = value._convert_to_address(cls) + return ctypes.cast(address, cls._ctype) + + @classmethod + def _from_ctypes(cls, ctypes_ptr): + address = ctypes.cast(ctypes_ptr, ctypes.c_void_p).value or 0 + return cls._new_pointer_at(address) + + @classmethod + def _initialize(cls, ctypes_ptr, value): + if value: + ctypes_ptr.contents = cls._to_ctypes(value).contents + + def _convert_to_address(self, BClass): + if (BClass in (self.__class__, None) or BClass._automatic_casts + or self._automatic_casts): + return self._address + else: + return CTypesData._convert_to_address(self, BClass) + + +class CTypesBaseStructOrUnion(CTypesData): + __slots__ = ['_blob'] + + @classmethod + def _create_ctype_obj(cls, init): + # may be overridden + raise TypeError("cannot instantiate opaque type %s" % (cls,)) + + def _get_own_repr(self): + return self._addr_repr(ctypes.addressof(self._blob)) + + @classmethod + def _offsetof(cls, fieldname): + return getattr(cls._ctype, fieldname).offset + + def _convert_to_address(self, BClass): + if getattr(BClass, '_BItem', None) is self.__class__: + return ctypes.addressof(self._blob) + else: + return CTypesData._convert_to_address(self, BClass) + + @classmethod + def _from_ctypes(cls, ctypes_struct_or_union): + self = cls.__new__(cls) + self._blob = ctypes_struct_or_union + return self + + @classmethod + def _to_ctypes(cls, value): + return value._blob + + def __repr__(self, c_name=None): + return CTypesData.__repr__(self, c_name or self._get_c_name(' &')) + + +class CTypesBackend(object): + + PRIMITIVE_TYPES = { + 'char': ctypes.c_char, + 'short': ctypes.c_short, + 'int': ctypes.c_int, + 'long': ctypes.c_long, + 'long long': ctypes.c_longlong, + 'signed char': ctypes.c_byte, + 'unsigned char': ctypes.c_ubyte, + 'unsigned short': ctypes.c_ushort, + 'unsigned int': ctypes.c_uint, + 'unsigned long': ctypes.c_ulong, + 'unsigned long long': ctypes.c_ulonglong, + 'float': ctypes.c_float, + 'double': ctypes.c_double, + '_Bool': ctypes.c_bool, + } + + for _name in ['unsigned long long', 'unsigned long', + 'unsigned int', 'unsigned short', 'unsigned char']: + _size = ctypes.sizeof(PRIMITIVE_TYPES[_name]) + PRIMITIVE_TYPES['uint%d_t' % (8*_size)] = PRIMITIVE_TYPES[_name] + if _size == ctypes.sizeof(ctypes.c_void_p): + PRIMITIVE_TYPES['uintptr_t'] = PRIMITIVE_TYPES[_name] + if _size == ctypes.sizeof(ctypes.c_size_t): + PRIMITIVE_TYPES['size_t'] = PRIMITIVE_TYPES[_name] + + for _name in ['long long', 'long', 'int', 'short', 'signed char']: + _size = ctypes.sizeof(PRIMITIVE_TYPES[_name]) + PRIMITIVE_TYPES['int%d_t' % (8*_size)] = PRIMITIVE_TYPES[_name] + if _size == ctypes.sizeof(ctypes.c_void_p): + PRIMITIVE_TYPES['intptr_t'] = PRIMITIVE_TYPES[_name] + PRIMITIVE_TYPES['ptrdiff_t'] = PRIMITIVE_TYPES[_name] + if _size == ctypes.sizeof(ctypes.c_size_t): + PRIMITIVE_TYPES['ssize_t'] = PRIMITIVE_TYPES[_name] + + + def __init__(self): + self.RTLD_LAZY = 0 # not supported anyway by ctypes + self.RTLD_NOW = 0 + self.RTLD_GLOBAL = ctypes.RTLD_GLOBAL + self.RTLD_LOCAL = ctypes.RTLD_LOCAL + + def set_ffi(self, ffi): + self.ffi = ffi + + def _get_types(self): + return CTypesData, CTypesType + + def load_library(self, path, flags=0): + cdll = ctypes.CDLL(path, flags) + return CTypesLibrary(self, cdll) + + def new_void_type(self): + class CTypesVoid(CTypesData): + __slots__ = [] + _reftypename = 'void &' + @staticmethod + def _from_ctypes(novalue): + return None + @staticmethod + def _to_ctypes(novalue): + if novalue is not None: + raise TypeError("None expected, got %s object" % + (type(novalue).__name__,)) + return None + CTypesVoid._fix_class() + return CTypesVoid + + def new_primitive_type(self, name): + if name == 'wchar_t': + raise NotImplementedError(name) + ctype = self.PRIMITIVE_TYPES[name] + if name == 'char': + kind = 'char' + elif name in ('float', 'double'): + kind = 'float' + else: + if name in ('signed char', 'unsigned char'): + kind = 'byte' + elif name == '_Bool': + kind = 'bool' + else: + kind = 'int' + is_signed = (ctype(-1).value == -1) + # + def _cast_source_to_int(source): + if isinstance(source, (int, long, float)): + source = int(source) + elif isinstance(source, CTypesData): + source = source._cast_to_integer() + elif isinstance(source, bytes): + source = ord(source) + elif source is None: + source = 0 + else: + raise TypeError("bad type for cast to %r: %r" % + (CTypesPrimitive, type(source).__name__)) + return source + # + kind1 = kind + class CTypesPrimitive(CTypesGenericPrimitive): + __slots__ = ['_value'] + _ctype = ctype + _reftypename = '%s &' % name + kind = kind1 + + def __init__(self, value): + self._value = value + + @staticmethod + def _create_ctype_obj(init): + if init is None: + return ctype() + return ctype(CTypesPrimitive._to_ctypes(init)) + + if kind == 'int' or kind == 'byte': + @classmethod + def _cast_from(cls, source): + source = _cast_source_to_int(source) + source = ctype(source).value # cast within range + return cls(source) + def __int__(self): + return self._value + + if kind == 'bool': + @classmethod + def _cast_from(cls, source): + if not isinstance(source, (int, long, float)): + source = _cast_source_to_int(source) + return cls(bool(source)) + def __int__(self): + return self._value + + if kind == 'char': + @classmethod + def _cast_from(cls, source): + source = _cast_source_to_int(source) + source = bytechr(source & 0xFF) + return cls(source) + def __int__(self): + return ord(self._value) + + if kind == 'float': + @classmethod + def _cast_from(cls, source): + if isinstance(source, float): + pass + elif isinstance(source, CTypesGenericPrimitive): + if hasattr(source, '__float__'): + source = float(source) + else: + source = int(source) + else: + source = _cast_source_to_int(source) + source = ctype(source).value # fix precision + return cls(source) + def __int__(self): + return int(self._value) + def __float__(self): + return self._value + + _cast_to_integer = __int__ + + if kind == 'int' or kind == 'byte' or kind == 'bool': + @staticmethod + def _to_ctypes(x): + if not isinstance(x, (int, long)): + if isinstance(x, CTypesData): + x = int(x) + else: + raise TypeError("integer expected, got %s" % + type(x).__name__) + if ctype(x).value != x: + if not is_signed and x < 0: + raise OverflowError("%s: negative integer" % name) + else: + raise OverflowError("%s: integer out of bounds" + % name) + return x + + if kind == 'char': + @staticmethod + def _to_ctypes(x): + if isinstance(x, bytes) and len(x) == 1: + return x + if isinstance(x, CTypesPrimitive): # <CData <char>> + return x._value + raise TypeError("character expected, got %s" % + type(x).__name__) + def __nonzero__(self): + return ord(self._value) != 0 + else: + def __nonzero__(self): + return self._value != 0 + __bool__ = __nonzero__ + + if kind == 'float': + @staticmethod + def _to_ctypes(x): + if not isinstance(x, (int, long, float, CTypesData)): + raise TypeError("float expected, got %s" % + type(x).__name__) + return ctype(x).value + + @staticmethod + def _from_ctypes(value): + return getattr(value, 'value', value) + + @staticmethod + def _initialize(blob, init): + blob.value = CTypesPrimitive._to_ctypes(init) + + if kind == 'char': + def _to_string(self, maxlen): + return self._value + if kind == 'byte': + def _to_string(self, maxlen): + return chr(self._value & 0xff) + # + CTypesPrimitive._fix_class() + return CTypesPrimitive + + def new_pointer_type(self, BItem): + getbtype = self.ffi._get_cached_btype + if BItem is getbtype(model.PrimitiveType('char')): + kind = 'charp' + elif BItem in (getbtype(model.PrimitiveType('signed char')), + getbtype(model.PrimitiveType('unsigned char'))): + kind = 'bytep' + elif BItem is getbtype(model.void_type): + kind = 'voidp' + else: + kind = 'generic' + # + class CTypesPtr(CTypesGenericPtr): + __slots__ = ['_own'] + if kind == 'charp': + __slots__ += ['__as_strbuf'] + _BItem = BItem + if hasattr(BItem, '_ctype'): + _ctype = ctypes.POINTER(BItem._ctype) + _bitem_size = ctypes.sizeof(BItem._ctype) + else: + _ctype = ctypes.c_void_p + if issubclass(BItem, CTypesGenericArray): + _reftypename = BItem._get_c_name('(* &)') + else: + _reftypename = BItem._get_c_name(' * &') + + def __init__(self, init): + ctypeobj = BItem._create_ctype_obj(init) + if kind == 'charp': + self.__as_strbuf = ctypes.create_string_buffer( + ctypeobj.value + b'\x00') + self._as_ctype_ptr = ctypes.cast( + self.__as_strbuf, self._ctype) + else: + self._as_ctype_ptr = ctypes.pointer(ctypeobj) + self._address = ctypes.cast(self._as_ctype_ptr, + ctypes.c_void_p).value + self._own = True + + def __add__(self, other): + if isinstance(other, (int, long)): + return self._new_pointer_at(self._address + + other * self._bitem_size) + else: + return NotImplemented + + def __sub__(self, other): + if isinstance(other, (int, long)): + return self._new_pointer_at(self._address - + other * self._bitem_size) + elif type(self) is type(other): + return (self._address - other._address) // self._bitem_size + else: + return NotImplemented + + def __getitem__(self, index): + if getattr(self, '_own', False) and index != 0: + raise IndexError + return BItem._from_ctypes(self._as_ctype_ptr[index]) + + def __setitem__(self, index, value): + self._as_ctype_ptr[index] = BItem._to_ctypes(value) + + if kind == 'charp' or kind == 'voidp': + @classmethod + def _arg_to_ctypes(cls, *value): + if value and isinstance(value[0], bytes): + return ctypes.c_char_p(value[0]) + else: + return super(CTypesPtr, cls)._arg_to_ctypes(*value) + + if kind == 'charp' or kind == 'bytep': + def _to_string(self, maxlen): + if maxlen < 0: + maxlen = sys.maxsize + p = ctypes.cast(self._as_ctype_ptr, + ctypes.POINTER(ctypes.c_char)) + n = 0 + while n < maxlen and p[n] != b'\x00': + n += 1 + return b''.join([p[i] for i in range(n)]) + + def _get_own_repr(self): + if getattr(self, '_own', False): + return 'owning %d bytes' % ( + ctypes.sizeof(self._as_ctype_ptr.contents),) + return super(CTypesPtr, self)._get_own_repr() + # + if (BItem is self.ffi._get_cached_btype(model.void_type) or + BItem is self.ffi._get_cached_btype(model.PrimitiveType('char'))): + CTypesPtr._automatic_casts = True + # + CTypesPtr._fix_class() + return CTypesPtr + + def new_array_type(self, CTypesPtr, length): + if length is None: + brackets = ' &[]' + else: + brackets = ' &[%d]' % length + BItem = CTypesPtr._BItem + getbtype = self.ffi._get_cached_btype + if BItem is getbtype(model.PrimitiveType('char')): + kind = 'char' + elif BItem in (getbtype(model.PrimitiveType('signed char')), + getbtype(model.PrimitiveType('unsigned char'))): + kind = 'byte' + else: + kind = 'generic' + # + class CTypesArray(CTypesGenericArray): + __slots__ = ['_blob', '_own'] + if length is not None: + _ctype = BItem._ctype * length + else: + __slots__.append('_ctype') + _reftypename = BItem._get_c_name(brackets) + _declared_length = length + _CTPtr = CTypesPtr + + def __init__(self, init): + if length is None: + if isinstance(init, (int, long)): + len1 = init + init = None + elif kind == 'char' and isinstance(init, bytes): + len1 = len(init) + 1 # extra null + else: + init = tuple(init) + len1 = len(init) + self._ctype = BItem._ctype * len1 + self._blob = self._ctype() + self._own = True + if init is not None: + self._initialize(self._blob, init) + + @staticmethod + def _initialize(blob, init): + if isinstance(init, bytes): + init = [init[i:i+1] for i in range(len(init))] + else: + if isinstance(init, CTypesGenericArray): + if (len(init) != len(blob) or + not isinstance(init, CTypesArray)): + raise TypeError("length/type mismatch: %s" % (init,)) + init = tuple(init) + if len(init) > len(blob): + raise IndexError("too many initializers") + addr = ctypes.cast(blob, ctypes.c_void_p).value + PTR = ctypes.POINTER(BItem._ctype) + itemsize = ctypes.sizeof(BItem._ctype) + for i, value in enumerate(init): + p = ctypes.cast(addr + i * itemsize, PTR) + BItem._initialize(p.contents, value) + + def __len__(self): + return len(self._blob) + + def __getitem__(self, index): + if not (0 <= index < len(self._blob)): + raise IndexError + return BItem._from_ctypes(self._blob[index]) + + def __setitem__(self, index, value): + if not (0 <= index < len(self._blob)): + raise IndexError + self._blob[index] = BItem._to_ctypes(value) + + if kind == 'char' or kind == 'byte': + def _to_string(self, maxlen): + if maxlen < 0: + maxlen = len(self._blob) + p = ctypes.cast(self._blob, + ctypes.POINTER(ctypes.c_char)) + n = 0 + while n < maxlen and p[n] != b'\x00': + n += 1 + return b''.join([p[i] for i in range(n)]) + + def _get_own_repr(self): + if getattr(self, '_own', False): + return 'owning %d bytes' % (ctypes.sizeof(self._blob),) + return super(CTypesArray, self)._get_own_repr() + + def _convert_to_address(self, BClass): + if BClass in (CTypesPtr, None) or BClass._automatic_casts: + return ctypes.addressof(self._blob) + else: + return CTypesData._convert_to_address(self, BClass) + + @staticmethod + def _from_ctypes(ctypes_array): + self = CTypesArray.__new__(CTypesArray) + self._blob = ctypes_array + return self + + @staticmethod + def _arg_to_ctypes(value): + return CTypesPtr._arg_to_ctypes(value) + + def __add__(self, other): + if isinstance(other, (int, long)): + return CTypesPtr._new_pointer_at( + ctypes.addressof(self._blob) + + other * ctypes.sizeof(BItem._ctype)) + else: + return NotImplemented + + @classmethod + def _cast_from(cls, source): + raise NotImplementedError("casting to %r" % ( + cls._get_c_name(),)) + # + CTypesArray._fix_class() + return CTypesArray + + def _new_struct_or_union(self, kind, name, base_ctypes_class): + # + class struct_or_union(base_ctypes_class): + pass + struct_or_union.__name__ = '%s_%s' % (kind, name) + kind1 = kind + # + class CTypesStructOrUnion(CTypesBaseStructOrUnion): + __slots__ = ['_blob'] + _ctype = struct_or_union + _reftypename = '%s &' % (name,) + _kind = kind = kind1 + # + CTypesStructOrUnion._fix_class() + return CTypesStructOrUnion + + def new_struct_type(self, name): + return self._new_struct_or_union('struct', name, ctypes.Structure) + + def new_union_type(self, name): + return self._new_struct_or_union('union', name, ctypes.Union) + + def complete_struct_or_union(self, CTypesStructOrUnion, fields, tp, + totalsize=-1, totalalignment=-1, sflags=0, + pack=0): + if totalsize >= 0 or totalalignment >= 0: + raise NotImplementedError("the ctypes backend of CFFI does not support " + "structures completed by verify(); please " + "compile and install the _cffi_backend module.") + struct_or_union = CTypesStructOrUnion._ctype + fnames = [fname for (fname, BField, bitsize) in fields] + btypes = [BField for (fname, BField, bitsize) in fields] + bitfields = [bitsize for (fname, BField, bitsize) in fields] + # + bfield_types = {} + cfields = [] + for (fname, BField, bitsize) in fields: + if bitsize < 0: + cfields.append((fname, BField._ctype)) + bfield_types[fname] = BField + else: + cfields.append((fname, BField._ctype, bitsize)) + bfield_types[fname] = Ellipsis + if sflags & 8: + struct_or_union._pack_ = 1 + elif pack: + struct_or_union._pack_ = pack + struct_or_union._fields_ = cfields + CTypesStructOrUnion._bfield_types = bfield_types + # + @staticmethod + def _create_ctype_obj(init): + result = struct_or_union() + if init is not None: + initialize(result, init) + return result + CTypesStructOrUnion._create_ctype_obj = _create_ctype_obj + # + def initialize(blob, init): + if is_union: + if len(init) > 1: + raise ValueError("union initializer: %d items given, but " + "only one supported (use a dict if needed)" + % (len(init),)) + if not isinstance(init, dict): + if isinstance(init, (bytes, unicode)): + raise TypeError("union initializer: got a str") + init = tuple(init) + if len(init) > len(fnames): + raise ValueError("too many values for %s initializer" % + CTypesStructOrUnion._get_c_name()) + init = dict(zip(fnames, init)) + addr = ctypes.addressof(blob) + for fname, value in init.items(): + BField, bitsize = name2fieldtype[fname] + assert bitsize < 0, \ + "not implemented: initializer with bit fields" + offset = CTypesStructOrUnion._offsetof(fname) + PTR = ctypes.POINTER(BField._ctype) + p = ctypes.cast(addr + offset, PTR) + BField._initialize(p.contents, value) + is_union = CTypesStructOrUnion._kind == 'union' + name2fieldtype = dict(zip(fnames, zip(btypes, bitfields))) + # + for fname, BField, bitsize in fields: + if fname == '': + raise NotImplementedError("nested anonymous structs/unions") + if hasattr(CTypesStructOrUnion, fname): + raise ValueError("the field name %r conflicts in " + "the ctypes backend" % fname) + if bitsize < 0: + def getter(self, fname=fname, BField=BField, + offset=CTypesStructOrUnion._offsetof(fname), + PTR=ctypes.POINTER(BField._ctype)): + addr = ctypes.addressof(self._blob) + p = ctypes.cast(addr + offset, PTR) + return BField._from_ctypes(p.contents) + def setter(self, value, fname=fname, BField=BField): + setattr(self._blob, fname, BField._to_ctypes(value)) + # + if issubclass(BField, CTypesGenericArray): + setter = None + if BField._declared_length == 0: + def getter(self, fname=fname, BFieldPtr=BField._CTPtr, + offset=CTypesStructOrUnion._offsetof(fname), + PTR=ctypes.POINTER(BField._ctype)): + addr = ctypes.addressof(self._blob) + p = ctypes.cast(addr + offset, PTR) + return BFieldPtr._from_ctypes(p) + # + else: + def getter(self, fname=fname, BField=BField): + return BField._from_ctypes(getattr(self._blob, fname)) + def setter(self, value, fname=fname, BField=BField): + # xxx obscure workaround + value = BField._to_ctypes(value) + oldvalue = getattr(self._blob, fname) + setattr(self._blob, fname, value) + if value != getattr(self._blob, fname): + setattr(self._blob, fname, oldvalue) + raise OverflowError("value too large for bitfield") + setattr(CTypesStructOrUnion, fname, property(getter, setter)) + # + CTypesPtr = self.ffi._get_cached_btype(model.PointerType(tp)) + for fname in fnames: + if hasattr(CTypesPtr, fname): + raise ValueError("the field name %r conflicts in " + "the ctypes backend" % fname) + def getter(self, fname=fname): + return getattr(self[0], fname) + def setter(self, value, fname=fname): + setattr(self[0], fname, value) + setattr(CTypesPtr, fname, property(getter, setter)) + + def new_function_type(self, BArgs, BResult, has_varargs): + nameargs = [BArg._get_c_name() for BArg in BArgs] + if has_varargs: + nameargs.append('...') + nameargs = ', '.join(nameargs) + # + class CTypesFunctionPtr(CTypesGenericPtr): + __slots__ = ['_own_callback', '_name'] + _ctype = ctypes.CFUNCTYPE(getattr(BResult, '_ctype', None), + *[BArg._ctype for BArg in BArgs], + use_errno=True) + _reftypename = BResult._get_c_name('(* &)(%s)' % (nameargs,)) + + def __init__(self, init, error=None): + # create a callback to the Python callable init() + import traceback + assert not has_varargs, "varargs not supported for callbacks" + if getattr(BResult, '_ctype', None) is not None: + error = BResult._from_ctypes( + BResult._create_ctype_obj(error)) + else: + error = None + def callback(*args): + args2 = [] + for arg, BArg in zip(args, BArgs): + args2.append(BArg._from_ctypes(arg)) + try: + res2 = init(*args2) + res2 = BResult._to_ctypes(res2) + except: + traceback.print_exc() + res2 = error + if issubclass(BResult, CTypesGenericPtr): + if res2: + res2 = ctypes.cast(res2, ctypes.c_void_p).value + # .value: http://bugs.python.org/issue1574593 + else: + res2 = None + #print repr(res2) + return res2 + if issubclass(BResult, CTypesGenericPtr): + # The only pointers callbacks can return are void*s: + # http://bugs.python.org/issue5710 + callback_ctype = ctypes.CFUNCTYPE( + ctypes.c_void_p, + *[BArg._ctype for BArg in BArgs], + use_errno=True) + else: + callback_ctype = CTypesFunctionPtr._ctype + self._as_ctype_ptr = callback_ctype(callback) + self._address = ctypes.cast(self._as_ctype_ptr, + ctypes.c_void_p).value + self._own_callback = init + + @staticmethod + def _initialize(ctypes_ptr, value): + if value: + raise NotImplementedError("ctypes backend: not supported: " + "initializers for function pointers") + + def __repr__(self): + c_name = getattr(self, '_name', None) + if c_name: + i = self._reftypename.index('(* &)') + if self._reftypename[i-1] not in ' )*': + c_name = ' ' + c_name + c_name = self._reftypename.replace('(* &)', c_name) + return CTypesData.__repr__(self, c_name) + + def _get_own_repr(self): + if getattr(self, '_own_callback', None) is not None: + return 'calling %r' % (self._own_callback,) + return super(CTypesFunctionPtr, self)._get_own_repr() + + def __call__(self, *args): + if has_varargs: + assert len(args) >= len(BArgs) + extraargs = args[len(BArgs):] + args = args[:len(BArgs)] + else: + assert len(args) == len(BArgs) + ctypes_args = [] + for arg, BArg in zip(args, BArgs): + ctypes_args.append(BArg._arg_to_ctypes(arg)) + if has_varargs: + for i, arg in enumerate(extraargs): + if arg is None: + ctypes_args.append(ctypes.c_void_p(0)) # NULL + continue + if not isinstance(arg, CTypesData): + raise TypeError( + "argument %d passed in the variadic part " + "needs to be a cdata object (got %s)" % + (1 + len(BArgs) + i, type(arg).__name__)) + ctypes_args.append(arg._arg_to_ctypes(arg)) + result = self._as_ctype_ptr(*ctypes_args) + return BResult._from_ctypes(result) + # + CTypesFunctionPtr._fix_class() + return CTypesFunctionPtr + + def new_enum_type(self, name, enumerators, enumvalues, CTypesInt): + assert isinstance(name, str) + reverse_mapping = dict(zip(reversed(enumvalues), + reversed(enumerators))) + # + class CTypesEnum(CTypesInt): + __slots__ = [] + _reftypename = '%s &' % name + + def _get_own_repr(self): + value = self._value + try: + return '%d: %s' % (value, reverse_mapping[value]) + except KeyError: + return str(value) + + def _to_string(self, maxlen): + value = self._value + try: + return reverse_mapping[value] + except KeyError: + return str(value) + # + CTypesEnum._fix_class() + return CTypesEnum + + def get_errno(self): + return ctypes.get_errno() + + def set_errno(self, value): + ctypes.set_errno(value) + + def string(self, b, maxlen=-1): + return b._to_string(maxlen) + + def buffer(self, bptr, size=-1): + raise NotImplementedError("buffer() with ctypes backend") + + def sizeof(self, cdata_or_BType): + if isinstance(cdata_or_BType, CTypesData): + return cdata_or_BType._get_size_of_instance() + else: + assert issubclass(cdata_or_BType, CTypesData) + return cdata_or_BType._get_size() + + def alignof(self, BType): + assert issubclass(BType, CTypesData) + return BType._alignment() + + def newp(self, BType, source): + if not issubclass(BType, CTypesData): + raise TypeError + return BType._newp(source) + + def cast(self, BType, source): + return BType._cast_from(source) + + def callback(self, BType, source, error, onerror): + assert onerror is None # XXX not implemented + return BType(source, error) + + _weakref_cache_ref = None + + def gcp(self, cdata, destructor, size=0): + if self._weakref_cache_ref is None: + import weakref + class MyRef(weakref.ref): + def __eq__(self, other): + myref = self() + return self is other or ( + myref is not None and myref is other()) + def __ne__(self, other): + return not (self == other) + def __hash__(self): + try: + return self._hash + except AttributeError: + self._hash = hash(self()) + return self._hash + self._weakref_cache_ref = {}, MyRef + weak_cache, MyRef = self._weakref_cache_ref + + if destructor is None: + try: + del weak_cache[MyRef(cdata)] + except KeyError: + raise TypeError("Can remove destructor only on a object " + "previously returned by ffi.gc()") + return None + + def remove(k): + cdata, destructor = weak_cache.pop(k, (None, None)) + if destructor is not None: + destructor(cdata) + + new_cdata = self.cast(self.typeof(cdata), cdata) + assert new_cdata is not cdata + weak_cache[MyRef(new_cdata, remove)] = (cdata, destructor) + return new_cdata + + typeof = type + + def getcname(self, BType, replace_with): + return BType._get_c_name(replace_with) + + def typeoffsetof(self, BType, fieldname, num=0): + if isinstance(fieldname, str): + if num == 0 and issubclass(BType, CTypesGenericPtr): + BType = BType._BItem + if not issubclass(BType, CTypesBaseStructOrUnion): + raise TypeError("expected a struct or union ctype") + BField = BType._bfield_types[fieldname] + if BField is Ellipsis: + raise TypeError("not supported for bitfields") + return (BField, BType._offsetof(fieldname)) + elif isinstance(fieldname, (int, long)): + if issubclass(BType, CTypesGenericArray): + BType = BType._CTPtr + if not issubclass(BType, CTypesGenericPtr): + raise TypeError("expected an array or ptr ctype") + BItem = BType._BItem + offset = BItem._get_size() * fieldname + if offset > sys.maxsize: + raise OverflowError + return (BItem, offset) + else: + raise TypeError(type(fieldname)) + + def rawaddressof(self, BTypePtr, cdata, offset=None): + if isinstance(cdata, CTypesBaseStructOrUnion): + ptr = ctypes.pointer(type(cdata)._to_ctypes(cdata)) + elif isinstance(cdata, CTypesGenericPtr): + if offset is None or not issubclass(type(cdata)._BItem, + CTypesBaseStructOrUnion): + raise TypeError("unexpected cdata type") + ptr = type(cdata)._to_ctypes(cdata) + elif isinstance(cdata, CTypesGenericArray): + ptr = type(cdata)._to_ctypes(cdata) + else: + raise TypeError("expected a <cdata 'struct-or-union'>") + if offset: + ptr = ctypes.cast( + ctypes.c_void_p( + ctypes.cast(ptr, ctypes.c_void_p).value + offset), + type(ptr)) + return BTypePtr._from_ctypes(ptr) + + +class CTypesLibrary(object): + + def __init__(self, backend, cdll): + self.backend = backend + self.cdll = cdll + + def load_function(self, BType, name): + c_func = getattr(self.cdll, name) + funcobj = BType._from_ctypes(c_func) + funcobj._name = name + return funcobj + + def read_variable(self, BType, name): + try: + ctypes_obj = BType._ctype.in_dll(self.cdll, name) + except AttributeError as e: + raise NotImplementedError(e) + return BType._from_ctypes(ctypes_obj) + + def write_variable(self, BType, name, value): + new_ctypes_obj = BType._to_ctypes(value) + ctypes_obj = BType._ctype.in_dll(self.cdll, name) + ctypes.memmove(ctypes.addressof(ctypes_obj), + ctypes.addressof(new_ctypes_obj), + ctypes.sizeof(BType._ctype)) |