diff options
Diffstat (limited to 'cffi/model.py')
| -rw-r--r-- | cffi/model.py | 614 |
1 files changed, 614 insertions, 0 deletions
diff --git a/cffi/model.py b/cffi/model.py new file mode 100644 index 0000000..5f1b0d2 --- /dev/null +++ b/cffi/model.py @@ -0,0 +1,614 @@ +import types +import weakref + +from .lock import allocate_lock +from .error import CDefError, VerificationError, VerificationMissing + +# type qualifiers +Q_CONST = 0x01 +Q_RESTRICT = 0x02 +Q_VOLATILE = 0x04 + +def qualify(quals, replace_with): + if quals & Q_CONST: + replace_with = ' const ' + replace_with.lstrip() + if quals & Q_VOLATILE: + replace_with = ' volatile ' + replace_with.lstrip() + if quals & Q_RESTRICT: + # It seems that __restrict is supported by gcc and msvc. + # If you hit some different compiler, add a #define in + # _cffi_include.h for it (and in its copies, documented there) + replace_with = ' __restrict ' + replace_with.lstrip() + return replace_with + + +class BaseTypeByIdentity(object): + is_array_type = False + is_raw_function = False + + def get_c_name(self, replace_with='', context='a C file', quals=0): + result = self.c_name_with_marker + assert result.count('&') == 1 + # some logic duplication with ffi.getctype()... :-( + replace_with = replace_with.strip() + if replace_with: + if replace_with.startswith('*') and '&[' in result: + replace_with = '(%s)' % replace_with + elif not replace_with[0] in '[(': + replace_with = ' ' + replace_with + replace_with = qualify(quals, replace_with) + result = result.replace('&', replace_with) + if '$' in result: + raise VerificationError( + "cannot generate '%s' in %s: unknown type name" + % (self._get_c_name(), context)) + return result + + def _get_c_name(self): + return self.c_name_with_marker.replace('&', '') + + def has_c_name(self): + return '$' not in self._get_c_name() + + def is_integer_type(self): + return False + + def get_cached_btype(self, ffi, finishlist, can_delay=False): + try: + BType = ffi._cached_btypes[self] + except KeyError: + BType = self.build_backend_type(ffi, finishlist) + BType2 = ffi._cached_btypes.setdefault(self, BType) + assert BType2 is BType + return BType + + def __repr__(self): + return '<%s>' % (self._get_c_name(),) + + def _get_items(self): + return [(name, getattr(self, name)) for name in self._attrs_] + + +class BaseType(BaseTypeByIdentity): + + def __eq__(self, other): + return (self.__class__ == other.__class__ and + self._get_items() == other._get_items()) + + def __ne__(self, other): + return not self == other + + def __hash__(self): + return hash((self.__class__, tuple(self._get_items()))) + + +class VoidType(BaseType): + _attrs_ = () + + def __init__(self): + self.c_name_with_marker = 'void&' + + def build_backend_type(self, ffi, finishlist): + return global_cache(self, ffi, 'new_void_type') + +void_type = VoidType() + + +class BasePrimitiveType(BaseType): + def is_complex_type(self): + return False + + +class PrimitiveType(BasePrimitiveType): + _attrs_ = ('name',) + + ALL_PRIMITIVE_TYPES = { + 'char': 'c', + 'short': 'i', + 'int': 'i', + 'long': 'i', + 'long long': 'i', + 'signed char': 'i', + 'unsigned char': 'i', + 'unsigned short': 'i', + 'unsigned int': 'i', + 'unsigned long': 'i', + 'unsigned long long': 'i', + 'float': 'f', + 'double': 'f', + 'long double': 'f', + 'float _Complex': 'j', + 'double _Complex': 'j', + '_Bool': 'i', + # the following types are not primitive in the C sense + 'wchar_t': 'c', + 'char16_t': 'c', + 'char32_t': 'c', + 'int8_t': 'i', + 'uint8_t': 'i', + 'int16_t': 'i', + 'uint16_t': 'i', + 'int32_t': 'i', + 'uint32_t': 'i', + 'int64_t': 'i', + 'uint64_t': 'i', + 'int_least8_t': 'i', + 'uint_least8_t': 'i', + 'int_least16_t': 'i', + 'uint_least16_t': 'i', + 'int_least32_t': 'i', + 'uint_least32_t': 'i', + 'int_least64_t': 'i', + 'uint_least64_t': 'i', + 'int_fast8_t': 'i', + 'uint_fast8_t': 'i', + 'int_fast16_t': 'i', + 'uint_fast16_t': 'i', + 'int_fast32_t': 'i', + 'uint_fast32_t': 'i', + 'int_fast64_t': 'i', + 'uint_fast64_t': 'i', + 'intptr_t': 'i', + 'uintptr_t': 'i', + 'intmax_t': 'i', + 'uintmax_t': 'i', + 'ptrdiff_t': 'i', + 'size_t': 'i', + 'ssize_t': 'i', + } + + def __init__(self, name): + assert name in self.ALL_PRIMITIVE_TYPES + self.name = name + self.c_name_with_marker = name + '&' + + def is_char_type(self): + return self.ALL_PRIMITIVE_TYPES[self.name] == 'c' + def is_integer_type(self): + return self.ALL_PRIMITIVE_TYPES[self.name] == 'i' + def is_float_type(self): + return self.ALL_PRIMITIVE_TYPES[self.name] == 'f' + def is_complex_type(self): + return self.ALL_PRIMITIVE_TYPES[self.name] == 'j' + + def build_backend_type(self, ffi, finishlist): + return global_cache(self, ffi, 'new_primitive_type', self.name) + + +class UnknownIntegerType(BasePrimitiveType): + _attrs_ = ('name',) + + def __init__(self, name): + self.name = name + self.c_name_with_marker = name + '&' + + def is_integer_type(self): + return True + + def build_backend_type(self, ffi, finishlist): + raise NotImplementedError("integer type '%s' can only be used after " + "compilation" % self.name) + +class UnknownFloatType(BasePrimitiveType): + _attrs_ = ('name', ) + + def __init__(self, name): + self.name = name + self.c_name_with_marker = name + '&' + + def build_backend_type(self, ffi, finishlist): + raise NotImplementedError("float type '%s' can only be used after " + "compilation" % self.name) + + +class BaseFunctionType(BaseType): + _attrs_ = ('args', 'result', 'ellipsis', 'abi') + + def __init__(self, args, result, ellipsis, abi=None): + self.args = args + self.result = result + self.ellipsis = ellipsis + self.abi = abi + # + reprargs = [arg._get_c_name() for arg in self.args] + if self.ellipsis: + reprargs.append('...') + reprargs = reprargs or ['void'] + replace_with = self._base_pattern % (', '.join(reprargs),) + if abi is not None: + replace_with = replace_with[:1] + abi + ' ' + replace_with[1:] + self.c_name_with_marker = ( + self.result.c_name_with_marker.replace('&', replace_with)) + + +class RawFunctionType(BaseFunctionType): + # Corresponds to a C type like 'int(int)', which is the C type of + # a function, but not a pointer-to-function. The backend has no + # notion of such a type; it's used temporarily by parsing. + _base_pattern = '(&)(%s)' + is_raw_function = True + + def build_backend_type(self, ffi, finishlist): + raise CDefError("cannot render the type %r: it is a function " + "type, not a pointer-to-function type" % (self,)) + + def as_function_pointer(self): + return FunctionPtrType(self.args, self.result, self.ellipsis, self.abi) + + +class FunctionPtrType(BaseFunctionType): + _base_pattern = '(*&)(%s)' + + def build_backend_type(self, ffi, finishlist): + result = self.result.get_cached_btype(ffi, finishlist) + args = [] + for tp in self.args: + args.append(tp.get_cached_btype(ffi, finishlist)) + abi_args = () + if self.abi == "__stdcall": + if not self.ellipsis: # __stdcall ignored for variadic funcs + try: + abi_args = (ffi._backend.FFI_STDCALL,) + except AttributeError: + pass + return global_cache(self, ffi, 'new_function_type', + tuple(args), result, self.ellipsis, *abi_args) + + def as_raw_function(self): + return RawFunctionType(self.args, self.result, self.ellipsis, self.abi) + + +class PointerType(BaseType): + _attrs_ = ('totype', 'quals') + + def __init__(self, totype, quals=0): + self.totype = totype + self.quals = quals + extra = qualify(quals, " *&") + if totype.is_array_type: + extra = "(%s)" % (extra.lstrip(),) + self.c_name_with_marker = totype.c_name_with_marker.replace('&', extra) + + def build_backend_type(self, ffi, finishlist): + BItem = self.totype.get_cached_btype(ffi, finishlist, can_delay=True) + return global_cache(self, ffi, 'new_pointer_type', BItem) + +voidp_type = PointerType(void_type) + +def ConstPointerType(totype): + return PointerType(totype, Q_CONST) + +const_voidp_type = ConstPointerType(void_type) + + +class NamedPointerType(PointerType): + _attrs_ = ('totype', 'name') + + def __init__(self, totype, name, quals=0): + PointerType.__init__(self, totype, quals) + self.name = name + self.c_name_with_marker = name + '&' + + +class ArrayType(BaseType): + _attrs_ = ('item', 'length') + is_array_type = True + + def __init__(self, item, length): + self.item = item + self.length = length + # + if length is None: + brackets = '&[]' + elif length == '...': + brackets = '&[/*...*/]' + else: + brackets = '&[%s]' % length + self.c_name_with_marker = ( + self.item.c_name_with_marker.replace('&', brackets)) + + def resolve_length(self, newlength): + return ArrayType(self.item, newlength) + + def build_backend_type(self, ffi, finishlist): + if self.length == '...': + raise CDefError("cannot render the type %r: unknown length" % + (self,)) + self.item.get_cached_btype(ffi, finishlist) # force the item BType + BPtrItem = PointerType(self.item).get_cached_btype(ffi, finishlist) + return global_cache(self, ffi, 'new_array_type', BPtrItem, self.length) + +char_array_type = ArrayType(PrimitiveType('char'), None) + + +class StructOrUnionOrEnum(BaseTypeByIdentity): + _attrs_ = ('name',) + forcename = None + + def build_c_name_with_marker(self): + name = self.forcename or '%s %s' % (self.kind, self.name) + self.c_name_with_marker = name + '&' + + def force_the_name(self, forcename): + self.forcename = forcename + self.build_c_name_with_marker() + + def get_official_name(self): + assert self.c_name_with_marker.endswith('&') + return self.c_name_with_marker[:-1] + + +class StructOrUnion(StructOrUnionOrEnum): + fixedlayout = None + completed = 0 + partial = False + packed = 0 + + def __init__(self, name, fldnames, fldtypes, fldbitsize, fldquals=None): + self.name = name + self.fldnames = fldnames + self.fldtypes = fldtypes + self.fldbitsize = fldbitsize + self.fldquals = fldquals + self.build_c_name_with_marker() + + def anonymous_struct_fields(self): + if self.fldtypes is not None: + for name, type in zip(self.fldnames, self.fldtypes): + if name == '' and isinstance(type, StructOrUnion): + yield type + + def enumfields(self, expand_anonymous_struct_union=True): + fldquals = self.fldquals + if fldquals is None: + fldquals = (0,) * len(self.fldnames) + for name, type, bitsize, quals in zip(self.fldnames, self.fldtypes, + self.fldbitsize, fldquals): + if (name == '' and isinstance(type, StructOrUnion) + and expand_anonymous_struct_union): + # nested anonymous struct/union + for result in type.enumfields(): + yield result + else: + yield (name, type, bitsize, quals) + + def force_flatten(self): + # force the struct or union to have a declaration that lists + # directly all fields returned by enumfields(), flattening + # nested anonymous structs/unions. + names = [] + types = [] + bitsizes = [] + fldquals = [] + for name, type, bitsize, quals in self.enumfields(): + names.append(name) + types.append(type) + bitsizes.append(bitsize) + fldquals.append(quals) + self.fldnames = tuple(names) + self.fldtypes = tuple(types) + self.fldbitsize = tuple(bitsizes) + self.fldquals = tuple(fldquals) + + def get_cached_btype(self, ffi, finishlist, can_delay=False): + BType = StructOrUnionOrEnum.get_cached_btype(self, ffi, finishlist, + can_delay) + if not can_delay: + self.finish_backend_type(ffi, finishlist) + return BType + + def finish_backend_type(self, ffi, finishlist): + if self.completed: + if self.completed != 2: + raise NotImplementedError("recursive structure declaration " + "for '%s'" % (self.name,)) + return + BType = ffi._cached_btypes[self] + # + self.completed = 1 + # + if self.fldtypes is None: + pass # not completing it: it's an opaque struct + # + elif self.fixedlayout is None: + fldtypes = [tp.get_cached_btype(ffi, finishlist) + for tp in self.fldtypes] + lst = list(zip(self.fldnames, fldtypes, self.fldbitsize)) + extra_flags = () + if self.packed: + if self.packed == 1: + extra_flags = (8,) # SF_PACKED + else: + extra_flags = (0, self.packed) + ffi._backend.complete_struct_or_union(BType, lst, self, + -1, -1, *extra_flags) + # + else: + fldtypes = [] + fieldofs, fieldsize, totalsize, totalalignment = self.fixedlayout + for i in range(len(self.fldnames)): + fsize = fieldsize[i] + ftype = self.fldtypes[i] + # + if isinstance(ftype, ArrayType) and ftype.length == '...': + # fix the length to match the total size + BItemType = ftype.item.get_cached_btype(ffi, finishlist) + nlen, nrest = divmod(fsize, ffi.sizeof(BItemType)) + if nrest != 0: + self._verification_error( + "field '%s.%s' has a bogus size?" % ( + self.name, self.fldnames[i] or '{}')) + ftype = ftype.resolve_length(nlen) + self.fldtypes = (self.fldtypes[:i] + (ftype,) + + self.fldtypes[i+1:]) + # + BFieldType = ftype.get_cached_btype(ffi, finishlist) + if isinstance(ftype, ArrayType) and ftype.length is None: + assert fsize == 0 + else: + bitemsize = ffi.sizeof(BFieldType) + if bitemsize != fsize: + self._verification_error( + "field '%s.%s' is declared as %d bytes, but is " + "really %d bytes" % (self.name, + self.fldnames[i] or '{}', + bitemsize, fsize)) + fldtypes.append(BFieldType) + # + lst = list(zip(self.fldnames, fldtypes, self.fldbitsize, fieldofs)) + ffi._backend.complete_struct_or_union(BType, lst, self, + totalsize, totalalignment) + self.completed = 2 + + def _verification_error(self, msg): + raise VerificationError(msg) + + def check_not_partial(self): + if self.partial and self.fixedlayout is None: + raise VerificationMissing(self._get_c_name()) + + def build_backend_type(self, ffi, finishlist): + self.check_not_partial() + finishlist.append(self) + # + return global_cache(self, ffi, 'new_%s_type' % self.kind, + self.get_official_name(), key=self) + + +class StructType(StructOrUnion): + kind = 'struct' + + +class UnionType(StructOrUnion): + kind = 'union' + + +class EnumType(StructOrUnionOrEnum): + kind = 'enum' + partial = False + partial_resolved = False + + def __init__(self, name, enumerators, enumvalues, baseinttype=None): + self.name = name + self.enumerators = enumerators + self.enumvalues = enumvalues + self.baseinttype = baseinttype + self.build_c_name_with_marker() + + def force_the_name(self, forcename): + StructOrUnionOrEnum.force_the_name(self, forcename) + if self.forcename is None: + name = self.get_official_name() + self.forcename = '$' + name.replace(' ', '_') + + def check_not_partial(self): + if self.partial and not self.partial_resolved: + raise VerificationMissing(self._get_c_name()) + + def build_backend_type(self, ffi, finishlist): + self.check_not_partial() + base_btype = self.build_baseinttype(ffi, finishlist) + return global_cache(self, ffi, 'new_enum_type', + self.get_official_name(), + self.enumerators, self.enumvalues, + base_btype, key=self) + + def build_baseinttype(self, ffi, finishlist): + if self.baseinttype is not None: + return self.baseinttype.get_cached_btype(ffi, finishlist) + # + if self.enumvalues: + smallest_value = min(self.enumvalues) + largest_value = max(self.enumvalues) + else: + import warnings + try: + # XXX! The goal is to ensure that the warnings.warn() + # will not suppress the warning. We want to get it + # several times if we reach this point several times. + __warningregistry__.clear() + except NameError: + pass + warnings.warn("%r has no values explicitly defined; " + "guessing that it is equivalent to 'unsigned int'" + % self._get_c_name()) + smallest_value = largest_value = 0 + if smallest_value < 0: # needs a signed type + sign = 1 + candidate1 = PrimitiveType("int") + candidate2 = PrimitiveType("long") + else: + sign = 0 + candidate1 = PrimitiveType("unsigned int") + candidate2 = PrimitiveType("unsigned long") + btype1 = candidate1.get_cached_btype(ffi, finishlist) + btype2 = candidate2.get_cached_btype(ffi, finishlist) + size1 = ffi.sizeof(btype1) + size2 = ffi.sizeof(btype2) + if (smallest_value >= ((-1) << (8*size1-1)) and + largest_value < (1 << (8*size1-sign))): + return btype1 + if (smallest_value >= ((-1) << (8*size2-1)) and + largest_value < (1 << (8*size2-sign))): + return btype2 + raise CDefError("%s values don't all fit into either 'long' " + "or 'unsigned long'" % self._get_c_name()) + +def unknown_type(name, structname=None): + if structname is None: + structname = '$%s' % name + tp = StructType(structname, None, None, None) + tp.force_the_name(name) + tp.origin = "unknown_type" + return tp + +def unknown_ptr_type(name, structname=None): + if structname is None: + structname = '$$%s' % name + tp = StructType(structname, None, None, None) + return NamedPointerType(tp, name) + + +global_lock = allocate_lock() +_typecache_cffi_backend = weakref.WeakValueDictionary() + +def get_typecache(backend): + # returns _typecache_cffi_backend if backend is the _cffi_backend + # module, or type(backend).__typecache if backend is an instance of + # CTypesBackend (or some FakeBackend class during tests) + if isinstance(backend, types.ModuleType): + return _typecache_cffi_backend + with global_lock: + if not hasattr(type(backend), '__typecache'): + type(backend).__typecache = weakref.WeakValueDictionary() + return type(backend).__typecache + +def global_cache(srctype, ffi, funcname, *args, **kwds): + key = kwds.pop('key', (funcname, args)) + assert not kwds + try: + return ffi._typecache[key] + except KeyError: + pass + try: + res = getattr(ffi._backend, funcname)(*args) + except NotImplementedError as e: + raise NotImplementedError("%s: %r: %s" % (funcname, srctype, e)) + # note that setdefault() on WeakValueDictionary is not atomic + # and contains a rare bug (http://bugs.python.org/issue19542); + # we have to use a lock and do it ourselves + cache = ffi._typecache + with global_lock: + res1 = cache.get(key) + if res1 is None: + cache[key] = res + return res + else: + return res1 + +def pointer_cache(ffi, BType): + return global_cache('?', ffi, 'new_pointer_type', BType) + +def attach_exception_info(e, name): + if e.args and type(e.args[0]) is str: + e.args = ('%s: %s' % (name, e.args[0]),) + e.args[1:] |