Upload api.py

cffi/api.py

@@ -0,0 +1,967 @@
+import sys, types
+from .lock import allocate_lock
+from .error import CDefError
+from . import model
+
+try:
+    callable
+except NameError:
+    # Python 3.1
+    from collections import Callable
+    callable = lambda x: isinstance(x, Callable)
+
+try:
+    basestring
+except NameError:
+    # Python 3.x
+    basestring = str
+
+_unspecified = object()
+
+
+
+class FFI(object):
+    r'''
+    The main top-level class that you instantiate once, or once per module.
+
+    Example usage:
+
+        ffi = FFI()
+        ffi.cdef("""
+            int printf(const char *, ...);
+        """)
+
+        C = ffi.dlopen(None)   # standard library
+        -or-
+        C = ffi.verify()  # use a C compiler: verify the decl above is right
+
+        C.printf("hello, %s!\n", ffi.new("char[]", "world"))
+    '''
+
+    def __init__(self, backend=None):
+        """Create an FFI instance.  The 'backend' argument is used to
+        select a non-default backend, mostly for tests.
+        """
+        if backend is None:
+            # You need PyPy (>= 2.0 beta), or a CPython (>= 2.6) with
+            # _cffi_backend.so compiled.
+            import _cffi_backend as backend
+            from . import __version__
+            if backend.__version__ != __version__:
+                # bad version!  Try to be as explicit as possible.
+                if hasattr(backend, '__file__'):
+                    # CPython
+                    raise Exception("Version mismatch: this is the 'cffi' package version %s, located in %r.  When we import the top-level '_cffi_backend' extension module, we get version %s, located in %r.  The two versions should be equal; check your installation." % (
+                        __version__, __file__,
+                        backend.__version__, backend.__file__))
+                else:
+                    # PyPy
+                    raise Exception("Version mismatch: this is the 'cffi' package version %s, located in %r.  This interpreter comes with a built-in '_cffi_backend' module, which is version %s.  The two versions should be equal; check your installation." % (
+                        __version__, __file__, backend.__version__))
+            # (If you insist you can also try to pass the option
+            # 'backend=backend_ctypes.CTypesBackend()', but don't
+            # rely on it!  It's probably not going to work well.)
+
+        from . import cparser
+        self._backend = backend
+        self._lock = allocate_lock()
+        self._parser = cparser.Parser()
+        self._cached_btypes = {}
+        self._parsed_types = types.ModuleType('parsed_types').__dict__
+        self._new_types = types.ModuleType('new_types').__dict__
+        self._function_caches = []
+        self._libraries = []
+        self._cdefsources = []
+        self._included_ffis = []
+        self._windows_unicode = None
+        self._init_once_cache = {}
+        self._cdef_version = None
+        self._embedding = None
+        self._typecache = model.get_typecache(backend)
+        if hasattr(backend, 'set_ffi'):
+            backend.set_ffi(self)
+        for name in list(backend.__dict__):
+            if name.startswith('RTLD_'):
+                setattr(self, name, getattr(backend, name))
+        #
+        with self._lock:
+            self.BVoidP = self._get_cached_btype(model.voidp_type)
+            self.BCharA = self._get_cached_btype(model.char_array_type)
+        if isinstance(backend, types.ModuleType):
+            # _cffi_backend: attach these constants to the class
+            if not hasattr(FFI, 'NULL'):
+                FFI.NULL = self.cast(self.BVoidP, 0)
+                FFI.CData, FFI.CType = backend._get_types()
+        else:
+            # ctypes backend: attach these constants to the instance
+            self.NULL = self.cast(self.BVoidP, 0)
+            self.CData, self.CType = backend._get_types()
+        self.buffer = backend.buffer
+
+    def cdef(self, csource, override=False, packed=False, pack=None):
+        """Parse the given C source.  This registers all declared functions,
+        types, and global variables.  The functions and global variables can
+        then be accessed via either 'ffi.dlopen()' or 'ffi.verify()'.
+        The types can be used in 'ffi.new()' and other functions.
+        If 'packed' is specified as True, all structs declared inside this
+        cdef are packed, i.e. laid out without any field alignment at all.
+        Alternatively, 'pack' can be a small integer, and requests for
+        alignment greater than that are ignored (pack=1 is equivalent to
+        packed=True).
+        """
+        self._cdef(csource, override=override, packed=packed, pack=pack)
+
+    def embedding_api(self, csource, packed=False, pack=None):
+        self._cdef(csource, packed=packed, pack=pack, dllexport=True)
+        if self._embedding is None:
+            self._embedding = ''
+
+    def _cdef(self, csource, override=False, **options):
+        if not isinstance(csource, str):    # unicode, on Python 2
+            if not isinstance(csource, basestring):
+                raise TypeError("cdef() argument must be a string")
+            csource = csource.encode('ascii')
+        with self._lock:
+            self._cdef_version = object()
+            self._parser.parse(csource, override=override, **options)
+            self._cdefsources.append(csource)
+            if override:
+                for cache in self._function_caches:
+                    cache.clear()
+            finishlist = self._parser._recomplete
+            if finishlist:
+                self._parser._recomplete = []
+                for tp in finishlist:
+                    tp.finish_backend_type(self, finishlist)
+
+    def dlopen(self, name, flags=0):
+        """Load and return a dynamic library identified by 'name'.
+        The standard C library can be loaded by passing None.
+        Note that functions and types declared by 'ffi.cdef()' are not
+        linked to a particular library, just like C headers; in the
+        library we only look for the actual (untyped) symbols.
+        """
+        if not (isinstance(name, basestring) or
+                name is None or
+                isinstance(name, self.CData)):
+            raise TypeError("dlopen(name): name must be a file name, None, "
+                            "or an already-opened 'void *' handle")
+        with self._lock:
+            lib, function_cache = _make_ffi_library(self, name, flags)
+            self._function_caches.append(function_cache)
+            self._libraries.append(lib)
+        return lib
+
+    def dlclose(self, lib):
+        """Close a library obtained with ffi.dlopen().  After this call,
+        access to functions or variables from the library will fail
+        (possibly with a segmentation fault).
+        """
+        type(lib).__cffi_close__(lib)
+
+    def _typeof_locked(self, cdecl):
+        # call me with the lock!
+        key = cdecl
+        if key in self._parsed_types:
+            return self._parsed_types[key]
+        #
+        if not isinstance(cdecl, str):    # unicode, on Python 2
+            cdecl = cdecl.encode('ascii')
+        #
+        type = self._parser.parse_type(cdecl)
+        really_a_function_type = type.is_raw_function
+        if really_a_function_type:
+            type = type.as_function_pointer()
+        btype = self._get_cached_btype(type)
+        result = btype, really_a_function_type
+        self._parsed_types[key] = result
+        return result
+
+    def _typeof(self, cdecl, consider_function_as_funcptr=False):
+        # string -> ctype object
+        try:
+            result = self._parsed_types[cdecl]
+        except KeyError:
+            with self._lock:
+                result = self._typeof_locked(cdecl)
+        #
+        btype, really_a_function_type = result
+        if really_a_function_type and not consider_function_as_funcptr:
+            raise CDefError("the type %r is a function type, not a "
+                            "pointer-to-function type" % (cdecl,))
+        return btype
+
+    def typeof(self, cdecl):
+        """Parse the C type given as a string and return the
+        corresponding <ctype> object.
+        It can also be used on 'cdata' instance to get its C type.
+        """
+        if isinstance(cdecl, basestring):
+            return self._typeof(cdecl)
+        if isinstance(cdecl, self.CData):
+            return self._backend.typeof(cdecl)
+        if isinstance(cdecl, types.BuiltinFunctionType):
+            res = _builtin_function_type(cdecl)
+            if res is not None:
+                return res
+        if (isinstance(cdecl, types.FunctionType)
+                and hasattr(cdecl, '_cffi_base_type')):
+            with self._lock:
+                return self._get_cached_btype(cdecl._cffi_base_type)
+        raise TypeError(type(cdecl))
+
+    def sizeof(self, cdecl):
+        """Return the size in bytes of the argument.  It can be a
+        string naming a C type, or a 'cdata' instance.
+        """
+        if isinstance(cdecl, basestring):
+            BType = self._typeof(cdecl)
+            return self._backend.sizeof(BType)
+        else:
+            return self._backend.sizeof(cdecl)
+
+    def alignof(self, cdecl):
+        """Return the natural alignment size in bytes of the C type
+        given as a string.
+        """
+        if isinstance(cdecl, basestring):
+            cdecl = self._typeof(cdecl)
+        return self._backend.alignof(cdecl)
+
+    def offsetof(self, cdecl, *fields_or_indexes):
+        """Return the offset of the named field inside the given
+        structure or array, which must be given as a C type name.
+        You can give several field names in case of nested structures.
+        You can also give numeric values which correspond to array
+        items, in case of an array type.
+        """
+        if isinstance(cdecl, basestring):
+            cdecl = self._typeof(cdecl)
+        return self._typeoffsetof(cdecl, *fields_or_indexes)[1]
+
+    def new(self, cdecl, init=None):
+        """Allocate an instance according to the specified C type and
+        return a pointer to it.  The specified C type must be either a
+        pointer or an array: ``new('X *')`` allocates an X and returns
+        a pointer to it, whereas ``new('X[n]')`` allocates an array of
+        n X'es and returns an array referencing it (which works
+        mostly like a pointer, like in C).  You can also use
+        ``new('X[]', n)`` to allocate an array of a non-constant
+        length n.
+
+        The memory is initialized following the rules of declaring a
+        global variable in C: by default it is zero-initialized, but
+        an explicit initializer can be given which can be used to
+        fill all or part of the memory.
+
+        When the returned <cdata> object goes out of scope, the memory
+        is freed.  In other words the returned <cdata> object has
+        ownership of the value of type 'cdecl' that it points to.  This
+        means that the raw data can be used as long as this object is
+        kept alive, but must not be used for a longer time.  Be careful
+        about that when copying the pointer to the memory somewhere
+        else, e.g. into another structure.
+        """
+        if isinstance(cdecl, basestring):
+            cdecl = self._typeof(cdecl)
+        return self._backend.newp(cdecl, init)
+
+    def new_allocator(self, alloc=None, free=None,
+                      should_clear_after_alloc=True):
+        """Return a new allocator, i.e. a function that behaves like ffi.new()
+        but uses the provided low-level 'alloc' and 'free' functions.
+
+        'alloc' is called with the size as argument.  If it returns NULL, a
+        MemoryError is raised.  'free' is called with the result of 'alloc'
+        as argument.  Both can be either Python function or directly C
+        functions.  If 'free' is None, then no free function is called.
+        If both 'alloc' and 'free' are None, the default is used.
+
+        If 'should_clear_after_alloc' is set to False, then the memory
+        returned by 'alloc' is assumed to be already cleared (or you are
+        fine with garbage); otherwise CFFI will clear it.
+        """
+        compiled_ffi = self._backend.FFI()
+        allocator = compiled_ffi.new_allocator(alloc, free,
+                                               should_clear_after_alloc)
+        def allocate(cdecl, init=None):
+            if isinstance(cdecl, basestring):
+                cdecl = self._typeof(cdecl)
+            return allocator(cdecl, init)
+        return allocate
+
+    def cast(self, cdecl, source):
+        """Similar to a C cast: returns an instance of the named C
+        type initialized with the given 'source'.  The source is
+        casted between integers or pointers of any type.
+        """
+        if isinstance(cdecl, basestring):
+            cdecl = self._typeof(cdecl)
+        return self._backend.cast(cdecl, source)
+
+    def string(self, cdata, maxlen=-1):
+        """Return a Python string (or unicode string) from the 'cdata'.
+        If 'cdata' is a pointer or array of characters or bytes, returns
+        the null-terminated string.  The returned string extends until
+        the first null character, or at most 'maxlen' characters.  If
+        'cdata' is an array then 'maxlen' defaults to its length.
+
+        If 'cdata' is a pointer or array of wchar_t, returns a unicode
+        string following the same rules.
+
+        If 'cdata' is a single character or byte or a wchar_t, returns
+        it as a string or unicode string.
+
+        If 'cdata' is an enum, returns the value of the enumerator as a
+        string, or 'NUMBER' if the value is out of range.
+        """
+        return self._backend.string(cdata, maxlen)
+
+    def unpack(self, cdata, length):
+        """Unpack an array of C data of the given length,
+        returning a Python string/unicode/list.
+
+        If 'cdata' is a pointer to 'char', returns a byte string.
+        It does not stop at the first null.  This is equivalent to:
+        ffi.buffer(cdata, length)[:]
+
+        If 'cdata' is a pointer to 'wchar_t', returns a unicode string.
+        'length' is measured in wchar_t's; it is not the size in bytes.
+
+        If 'cdata' is a pointer to anything else, returns a list of
+        'length' items.  This is a faster equivalent to:
+        [cdata[i] for i in range(length)]
+        """
+        return self._backend.unpack(cdata, length)
+
+   #def buffer(self, cdata, size=-1):
+   #    """Return a read-write buffer object that references the raw C data
+   #    pointed to by the given 'cdata'.  The 'cdata' must be a pointer or
+   #    an array.  Can be passed to functions expecting a buffer, or directly
+   #    manipulated with:
+   #
+   #        buf[:]          get a copy of it in a regular string, or
+   #        buf[idx]        as a single character
+   #        buf[:] = ...
+   #        buf[idx] = ...  change the content
+   #    """
+   #    note that 'buffer' is a type, set on this instance by __init__
+
+    def from_buffer(self, cdecl, python_buffer=_unspecified,
+                    require_writable=False):
+        """Return a cdata of the given type pointing to the data of the
+        given Python object, which must support the buffer interface.
+        Note that this is not meant to be used on the built-in types
+        str or unicode (you can build 'char[]' arrays explicitly)
+        but only on objects containing large quantities of raw data
+        in some other format, like 'array.array' or numpy arrays.
+
+        The first argument is optional and default to 'char[]'.
+        """
+        if python_buffer is _unspecified:
+            cdecl, python_buffer = self.BCharA, cdecl
+        elif isinstance(cdecl, basestring):
+            cdecl = self._typeof(cdecl)
+        return self._backend.from_buffer(cdecl, python_buffer,
+                                         require_writable)
+
+    def memmove(self, dest, src, n):
+        """ffi.memmove(dest, src, n) copies n bytes of memory from src to dest.
+
+        Like the C function memmove(), the memory areas may overlap;
+        apart from that it behaves like the C function memcpy().
+
+        'src' can be any cdata ptr or array, or any Python buffer object.
+        'dest' can be any cdata ptr or array, or a writable Python buffer
+        object.  The size to copy, 'n', is always measured in bytes.
+
+        Unlike other methods, this one supports all Python buffer including
+        byte strings and bytearrays---but it still does not support
+        non-contiguous buffers.
+        """
+        return self._backend.memmove(dest, src, n)
+
+    def callback(self, cdecl, python_callable=None, error=None, onerror=None):
+        """Return a callback object or a decorator making such a
+        callback object.  'cdecl' must name a C function pointer type.
+        The callback invokes the specified 'python_callable' (which may
+        be provided either directly or via a decorator).  Important: the
+        callback object must be manually kept alive for as long as the
+        callback may be invoked from the C level.
+        """
+        def callback_decorator_wrap(python_callable):
+            if not callable(python_callable):
+                raise TypeError("the 'python_callable' argument "
+                                "is not callable")
+            return self._backend.callback(cdecl, python_callable,
+                                          error, onerror)
+        if isinstance(cdecl, basestring):
+            cdecl = self._typeof(cdecl, consider_function_as_funcptr=True)
+        if python_callable is None:
+            return callback_decorator_wrap                # decorator mode
+        else:
+            return callback_decorator_wrap(python_callable)  # direct mode
+
+    def getctype(self, cdecl, replace_with=''):
+        """Return a string giving the C type 'cdecl', which may be itself
+        a string or a <ctype> object.  If 'replace_with' is given, it gives
+        extra text to append (or insert for more complicated C types), like
+        a variable name, or '*' to get actually the C type 'pointer-to-cdecl'.
+        """
+        if isinstance(cdecl, basestring):
+            cdecl = self._typeof(cdecl)
+        replace_with = replace_with.strip()
+        if (replace_with.startswith('*')
+                and '&[' in self._backend.getcname(cdecl, '&')):
+            replace_with = '(%s)' % replace_with
+        elif replace_with and not replace_with[0] in '[(':
+            replace_with = ' ' + replace_with
+        return self._backend.getcname(cdecl, replace_with)
+
+    def gc(self, cdata, destructor, size=0):
+        """Return a new cdata object that points to the same
+        data.  Later, when this new cdata object is garbage-collected,
+        'destructor(old_cdata_object)' will be called.
+
+        The optional 'size' gives an estimate of the size, used to
+        trigger the garbage collection more eagerly.  So far only used
+        on PyPy.  It tells the GC that the returned object keeps alive
+        roughly 'size' bytes of external memory.
+        """
+        return self._backend.gcp(cdata, destructor, size)
+
+    def _get_cached_btype(self, type):
+        assert self._lock.acquire(False) is False
+        # call me with the lock!
+        try:
+            BType = self._cached_btypes[type]
+        except KeyError:
+            finishlist = []
+            BType = type.get_cached_btype(self, finishlist)
+            for type in finishlist:
+                type.finish_backend_type(self, finishlist)
+        return BType
+
+    def verify(self, source='', tmpdir=None, **kwargs):
+        """Verify that the current ffi signatures compile on this
+        machine, and return a dynamic library object.  The dynamic
+        library can be used to call functions and access global
+        variables declared in this 'ffi'.  The library is compiled
+        by the C compiler: it gives you C-level API compatibility
+        (including calling macros).  This is unlike 'ffi.dlopen()',
+        which requires binary compatibility in the signatures.
+        """
+        from .verifier import Verifier, _caller_dir_pycache
+        #
+        # If set_unicode(True) was called, insert the UNICODE and
+        # _UNICODE macro declarations
+        if self._windows_unicode:
+            self._apply_windows_unicode(kwargs)
+        #
+        # Set the tmpdir here, and not in Verifier.__init__: it picks
+        # up the caller's directory, which we want to be the caller of
+        # ffi.verify(), as opposed to the caller of Veritier().
+        tmpdir = tmpdir or _caller_dir_pycache()
+        #
+        # Make a Verifier() and use it to load the library.
+        self.verifier = Verifier(self, source, tmpdir, **kwargs)
+        lib = self.verifier.load_library()
+        #
+        # Save the loaded library for keep-alive purposes, even
+        # if the caller doesn't keep it alive itself (it should).
+        self._libraries.append(lib)
+        return lib
+
+    def _get_errno(self):
+        return self._backend.get_errno()
+    def _set_errno(self, errno):
+        self._backend.set_errno(errno)
+    errno = property(_get_errno, _set_errno, None,
+                     "the value of 'errno' from/to the C calls")
+
+    def getwinerror(self, code=-1):
+        return self._backend.getwinerror(code)
+
+    def _pointer_to(self, ctype):
+        with self._lock:
+            return model.pointer_cache(self, ctype)
+
+    def addressof(self, cdata, *fields_or_indexes):
+        """Return the address of a <cdata 'struct-or-union'>.
+        If 'fields_or_indexes' are given, returns the address of that
+        field or array item in the structure or array, recursively in
+        case of nested structures.
+        """
+        try:
+            ctype = self._backend.typeof(cdata)
+        except TypeError:
+            if '__addressof__' in type(cdata).__dict__:
+                return type(cdata).__addressof__(cdata, *fields_or_indexes)
+            raise
+        if fields_or_indexes:
+            ctype, offset = self._typeoffsetof(ctype, *fields_or_indexes)
+        else:
+            if ctype.kind == "pointer":
+                raise TypeError("addressof(pointer)")
+            offset = 0
+        ctypeptr = self._pointer_to(ctype)
+        return self._backend.rawaddressof(ctypeptr, cdata, offset)
+
+    def _typeoffsetof(self, ctype, field_or_index, *fields_or_indexes):
+        ctype, offset = self._backend.typeoffsetof(ctype, field_or_index)
+        for field1 in fields_or_indexes:
+            ctype, offset1 = self._backend.typeoffsetof(ctype, field1, 1)
+            offset += offset1
+        return ctype, offset
+
+    def include(self, ffi_to_include):
+        """Includes the typedefs, structs, unions and enums defined
+        in another FFI instance.  Usage is similar to a #include in C,
+        where a part of the program might include types defined in
+        another part for its own usage.  Note that the include()
+        method has no effect on functions, constants and global
+        variables, which must anyway be accessed directly from the
+        lib object returned by the original FFI instance.
+        """
+        if not isinstance(ffi_to_include, FFI):
+            raise TypeError("ffi.include() expects an argument that is also of"
+                            " type cffi.FFI, not %r" % (
+                                type(ffi_to_include).__name__,))
+        if ffi_to_include is self:
+            raise ValueError("self.include(self)")
+        with ffi_to_include._lock:
+            with self._lock:
+                self._parser.include(ffi_to_include._parser)
+                self._cdefsources.append('[')
+                self._cdefsources.extend(ffi_to_include._cdefsources)
+                self._cdefsources.append(']')
+                self._included_ffis.append(ffi_to_include)
+
+    def new_handle(self, x):
+        return self._backend.newp_handle(self.BVoidP, x)
+
+    def from_handle(self, x):
+        return self._backend.from_handle(x)
+
+    def release(self, x):
+        self._backend.release(x)
+
+    def set_unicode(self, enabled_flag):
+        """Windows: if 'enabled_flag' is True, enable the UNICODE and
+        _UNICODE defines in C, and declare the types like TCHAR and LPTCSTR
+        to be (pointers to) wchar_t.  If 'enabled_flag' is False,
+        declare these types to be (pointers to) plain 8-bit characters.
+        This is mostly for backward compatibility; you usually want True.
+        """
+        if self._windows_unicode is not None:
+            raise ValueError("set_unicode() can only be called once")
+        enabled_flag = bool(enabled_flag)
+        if enabled_flag:
+            self.cdef("typedef wchar_t TBYTE;"
+                      "typedef wchar_t TCHAR;"
+                      "typedef const wchar_t *LPCTSTR;"
+                      "typedef const wchar_t *PCTSTR;"
+                      "typedef wchar_t *LPTSTR;"
+                      "typedef wchar_t *PTSTR;"
+                      "typedef TBYTE *PTBYTE;"
+                      "typedef TCHAR *PTCHAR;")
+        else:
+            self.cdef("typedef char TBYTE;"
+                      "typedef char TCHAR;"
+                      "typedef const char *LPCTSTR;"
+                      "typedef const char *PCTSTR;"
+                      "typedef char *LPTSTR;"
+                      "typedef char *PTSTR;"
+                      "typedef TBYTE *PTBYTE;"
+                      "typedef TCHAR *PTCHAR;")
+        self._windows_unicode = enabled_flag
+
+    def _apply_windows_unicode(self, kwds):
+        defmacros = kwds.get('define_macros', ())
+        if not isinstance(defmacros, (list, tuple)):
+            raise TypeError("'define_macros' must be a list or tuple")
+        defmacros = list(defmacros) + [('UNICODE', '1'),
+                                       ('_UNICODE', '1')]
+        kwds['define_macros'] = defmacros
+
+    def _apply_embedding_fix(self, kwds):
+        # must include an argument like "-lpython2.7" for the compiler
+        def ensure(key, value):
+            lst = kwds.setdefault(key, [])
+            if value not in lst:
+                lst.append(value)
+        #
+        if '__pypy__' in sys.builtin_module_names:
+            import os
+            if sys.platform == "win32":
+                # we need 'libpypy-c.lib'.  Current distributions of
+                # pypy (>= 4.1) contain it as 'libs/python27.lib'.
+                pythonlib = "python{0[0]}{0[1]}".format(sys.version_info)
+                if hasattr(sys, 'prefix'):
+                    ensure('library_dirs', os.path.join(sys.prefix, 'libs'))
+            else:
+                # we need 'libpypy-c.{so,dylib}', which should be by
+                # default located in 'sys.prefix/bin' for installed
+                # systems.
+                if sys.version_info < (3,):
+                    pythonlib = "pypy-c"
+                else:
+                    pythonlib = "pypy3-c"
+                if hasattr(sys, 'prefix'):
+                    ensure('library_dirs', os.path.join(sys.prefix, 'bin'))
+            # On uninstalled pypy's, the libpypy-c is typically found in
+            # .../pypy/goal/.
+            if hasattr(sys, 'prefix'):
+                ensure('library_dirs', os.path.join(sys.prefix, 'pypy', 'goal'))
+        else:
+            if sys.platform == "win32":
+                template = "python%d%d"
+                if hasattr(sys, 'gettotalrefcount'):
+                    template += '_d'
+            else:
+                try:
+                    import sysconfig
+                except ImportError:    # 2.6
+                    from cffi._shimmed_dist_utils import sysconfig
+                template = "python%d.%d"
+                if sysconfig.get_config_var('DEBUG_EXT'):
+                    template += sysconfig.get_config_var('DEBUG_EXT')
+            pythonlib = (template %
+                    (sys.hexversion >> 24, (sys.hexversion >> 16) & 0xff))
+            if hasattr(sys, 'abiflags'):
+                pythonlib += sys.abiflags
+        ensure('libraries', pythonlib)
+        if sys.platform == "win32":
+            ensure('extra_link_args', '/MANIFEST')
+
+    def set_source(self, module_name, source, source_extension='.c', **kwds):
+        import os
+        if hasattr(self, '_assigned_source'):
+            raise ValueError("set_source() cannot be called several times "
+                             "per ffi object")
+        if not isinstance(module_name, basestring):
+            raise TypeError("'module_name' must be a string")
+        if os.sep in module_name or (os.altsep and os.altsep in module_name):
+            raise ValueError("'module_name' must not contain '/': use a dotted "
+                             "name to make a 'package.module' location")
+        self._assigned_source = (str(module_name), source,
+                                 source_extension, kwds)
+
+    def set_source_pkgconfig(self, module_name, pkgconfig_libs, source,
+                             source_extension='.c', **kwds):
+        from . import pkgconfig
+        if not isinstance(pkgconfig_libs, list):
+            raise TypeError("the pkgconfig_libs argument must be a list "
+                            "of package names")
+        kwds2 = pkgconfig.flags_from_pkgconfig(pkgconfig_libs)
+        pkgconfig.merge_flags(kwds, kwds2)
+        self.set_source(module_name, source, source_extension, **kwds)
+
+    def distutils_extension(self, tmpdir='build', verbose=True):
+        from cffi._shimmed_dist_utils import mkpath
+        from .recompiler import recompile
+        #
+        if not hasattr(self, '_assigned_source'):
+            if hasattr(self, 'verifier'):     # fallback, 'tmpdir' ignored
+                return self.verifier.get_extension()
+            raise ValueError("set_source() must be called before"
+                             " distutils_extension()")
+        module_name, source, source_extension, kwds = self._assigned_source
+        if source is None:
+            raise TypeError("distutils_extension() is only for C extension "
+                            "modules, not for dlopen()-style pure Python "
+                            "modules")
+        mkpath(tmpdir)
+        ext, updated = recompile(self, module_name,
+                                 source, tmpdir=tmpdir, extradir=tmpdir,
+                                 source_extension=source_extension,
+                                 call_c_compiler=False, **kwds)
+        if verbose:
+            if updated:
+                sys.stderr.write("regenerated: %r\n" % (ext.sources[0],))
+            else:
+                sys.stderr.write("not modified: %r\n" % (ext.sources[0],))
+        return ext
+
+    def emit_c_code(self, filename):
+        from .recompiler import recompile
+        #
+        if not hasattr(self, '_assigned_source'):
+            raise ValueError("set_source() must be called before emit_c_code()")
+        module_name, source, source_extension, kwds = self._assigned_source
+        if source is None:
+            raise TypeError("emit_c_code() is only for C extension modules, "
+                            "not for dlopen()-style pure Python modules")
+        recompile(self, module_name, source,
+                  c_file=filename, call_c_compiler=False,
+                  uses_ffiplatform=False, **kwds)
+
+    def emit_python_code(self, filename):
+        from .recompiler import recompile
+        #
+        if not hasattr(self, '_assigned_source'):
+            raise ValueError("set_source() must be called before emit_c_code()")
+        module_name, source, source_extension, kwds = self._assigned_source
+        if source is not None:
+            raise TypeError("emit_python_code() is only for dlopen()-style "
+                            "pure Python modules, not for C extension modules")
+        recompile(self, module_name, source,
+                  c_file=filename, call_c_compiler=False,
+                  uses_ffiplatform=False, **kwds)
+
+    def compile(self, tmpdir='.', verbose=0, target=None, debug=None):
+        """The 'target' argument gives the final file name of the
+        compiled DLL.  Use '*' to force distutils' choice, suitable for
+        regular CPython C API modules.  Use a file name ending in '.*'
+        to ask for the system's default extension for dynamic libraries
+        (.so/.dll/.dylib).
+
+        The default is '*' when building a non-embedded C API extension,
+        and (module_name + '.*') when building an embedded library.
+        """
+        from .recompiler import recompile
+        #
+        if not hasattr(self, '_assigned_source'):
+            raise ValueError("set_source() must be called before compile()")
+        module_name, source, source_extension, kwds = self._assigned_source
+        return recompile(self, module_name, source, tmpdir=tmpdir,
+                         target=target, source_extension=source_extension,
+                         compiler_verbose=verbose, debug=debug, **kwds)
+
+    def init_once(self, func, tag):
+        # Read _init_once_cache[tag], which is either (False, lock) if
+        # we're calling the function now in some thread, or (True, result).
+        # Don't call setdefault() in most cases, to avoid allocating and
+        # immediately freeing a lock; but still use setdefaut() to avoid
+        # races.
+        try:
+            x = self._init_once_cache[tag]
+        except KeyError:
+            x = self._init_once_cache.setdefault(tag, (False, allocate_lock()))
+        # Common case: we got (True, result), so we return the result.
+        if x[0]:
+            return x[1]
+        # Else, it's a lock.  Acquire it to serialize the following tests.
+        with x[1]:
+            # Read again from _init_once_cache the current status.
+            x = self._init_once_cache[tag]
+            if x[0]:
+                return x[1]
+            # Call the function and store the result back.
+            result = func()
+            self._init_once_cache[tag] = (True, result)
+        return result
+
+    def embedding_init_code(self, pysource):
+        if self._embedding:
+            raise ValueError("embedding_init_code() can only be called once")
+        # fix 'pysource' before it gets dumped into the C file:
+        # - remove empty lines at the beginning, so it starts at "line 1"
+        # - dedent, if all non-empty lines are indented
+        # - check for SyntaxErrors
+        import re
+        match = re.match(r'\s*\n', pysource)
+        if match:
+            pysource = pysource[match.end():]
+        lines = pysource.splitlines() or ['']
+        prefix = re.match(r'\s*', lines[0]).group()
+        for i in range(1, len(lines)):
+            line = lines[i]
+            if line.rstrip():
+                while not line.startswith(prefix):
+                    prefix = prefix[:-1]
+        i = len(prefix)
+        lines = [line[i:]+'\n' for line in lines]
+        pysource = ''.join(lines)
+        #
+        compile(pysource, "cffi_init", "exec")
+        #
+        self._embedding = pysource
+
+    def def_extern(self, *args, **kwds):
+        raise ValueError("ffi.def_extern() is only available on API-mode FFI "
+                         "objects")
+
+    def list_types(self):
+        """Returns the user type names known to this FFI instance.
+        This returns a tuple containing three lists of names:
+        (typedef_names, names_of_structs, names_of_unions)
+        """
+        typedefs = []
+        structs = []
+        unions = []
+        for key in self._parser._declarations:
+            if key.startswith('typedef '):
+                typedefs.append(key[8:])
+            elif key.startswith('struct '):
+                structs.append(key[7:])
+            elif key.startswith('union '):
+                unions.append(key[6:])
+        typedefs.sort()
+        structs.sort()
+        unions.sort()
+        return (typedefs, structs, unions)
+
+
+def _load_backend_lib(backend, name, flags):
+    import os
+    if not isinstance(name, basestring):
+        if sys.platform != "win32" or name is not None:
+            return backend.load_library(name, flags)
+        name = "c"    # Windows: load_library(None) fails, but this works
+                      # on Python 2 (backward compatibility hack only)
+    first_error = None
+    if '.' in name or '/' in name or os.sep in name:
+        try:
+            return backend.load_library(name, flags)
+        except OSError as e:
+            first_error = e
+    import ctypes.util
+    path = ctypes.util.find_library(name)
+    if path is None:
+        if name == "c" and sys.platform == "win32" and sys.version_info >= (3,):
+            raise OSError("dlopen(None) cannot work on Windows for Python 3 "
+                          "(see http://bugs.python.org/issue23606)")
+        msg = ("ctypes.util.find_library() did not manage "
+               "to locate a library called %r" % (name,))
+        if first_error is not None:
+            msg = "%s.  Additionally, %s" % (first_error, msg)
+        raise OSError(msg)
+    return backend.load_library(path, flags)
+
+def _make_ffi_library(ffi, libname, flags):
+    backend = ffi._backend
+    backendlib = _load_backend_lib(backend, libname, flags)
+    #
+    def accessor_function(name):
+        key = 'function ' + name
+        tp, _ = ffi._parser._declarations[key]
+        BType = ffi._get_cached_btype(tp)
+        value = backendlib.load_function(BType, name)
+        library.__dict__[name] = value
+    #
+    def accessor_variable(name):
+        key = 'variable ' + name
+        tp, _ = ffi._parser._declarations[key]
+        BType = ffi._get_cached_btype(tp)
+        read_variable = backendlib.read_variable
+        write_variable = backendlib.write_variable
+        setattr(FFILibrary, name, property(
+            lambda self: read_variable(BType, name),
+            lambda self, value: write_variable(BType, name, value)))
+    #
+    def addressof_var(name):
+        try:
+            return addr_variables[name]
+        except KeyError:
+            with ffi._lock:
+                if name not in addr_variables:
+                    key = 'variable ' + name
+                    tp, _ = ffi._parser._declarations[key]
+                    BType = ffi._get_cached_btype(tp)
+                    if BType.kind != 'array':
+                        BType = model.pointer_cache(ffi, BType)
+                    p = backendlib.load_function(BType, name)
+                    addr_variables[name] = p
+            return addr_variables[name]
+    #
+    def accessor_constant(name):
+        raise NotImplementedError("non-integer constant '%s' cannot be "
+                                  "accessed from a dlopen() library" % (name,))
+    #
+    def accessor_int_constant(name):
+        library.__dict__[name] = ffi._parser._int_constants[name]
+    #
+    accessors = {}
+    accessors_version = [False]
+    addr_variables = {}
+    #
+    def update_accessors():
+        if accessors_version[0] is ffi._cdef_version:
+            return
+        #
+        for key, (tp, _) in ffi._parser._declarations.items():
+            if not isinstance(tp, model.EnumType):
+                tag, name = key.split(' ', 1)
+                if tag == 'function':
+                    accessors[name] = accessor_function
+                elif tag == 'variable':
+                    accessors[name] = accessor_variable
+                elif tag == 'constant':
+                    accessors[name] = accessor_constant
+            else:
+                for i, enumname in enumerate(tp.enumerators):
+                    def accessor_enum(name, tp=tp, i=i):
+                        tp.check_not_partial()
+                        library.__dict__[name] = tp.enumvalues[i]
+                    accessors[enumname] = accessor_enum
+        for name in ffi._parser._int_constants:
+            accessors.setdefault(name, accessor_int_constant)
+        accessors_version[0] = ffi._cdef_version
+    #
+    def make_accessor(name):
+        with ffi._lock:
+            if name in library.__dict__ or name in FFILibrary.__dict__:
+                return    # added by another thread while waiting for the lock
+            if name not in accessors:
+                update_accessors()
+                if name not in accessors:
+                    raise AttributeError(name)
+            accessors[name](name)
+    #
+    class FFILibrary(object):
+        def __getattr__(self, name):
+            make_accessor(name)
+            return getattr(self, name)
+        def __setattr__(self, name, value):
+            try:
+                property = getattr(self.__class__, name)
+            except AttributeError:
+                make_accessor(name)
+                setattr(self, name, value)
+            else:
+                property.__set__(self, value)
+        def __dir__(self):
+            with ffi._lock:
+                update_accessors()
+                return accessors.keys()
+        def __addressof__(self, name):
+            if name in library.__dict__:
+                return library.__dict__[name]
+            if name in FFILibrary.__dict__:
+                return addressof_var(name)
+            make_accessor(name)
+            if name in library.__dict__:
+                return library.__dict__[name]
+            if name in FFILibrary.__dict__:
+                return addressof_var(name)
+            raise AttributeError("cffi library has no function or "
+                                 "global variable named '%s'" % (name,))
+        def __cffi_close__(self):
+            backendlib.close_lib()
+            self.__dict__.clear()
+    #
+    if isinstance(libname, basestring):
+        try:
+            if not isinstance(libname, str):    # unicode, on Python 2
+                libname = libname.encode('utf-8')
+            FFILibrary.__name__ = 'FFILibrary_%s' % libname
+        except UnicodeError:
+            pass
+    library = FFILibrary()
+    return library, library.__dict__
+
+def _builtin_function_type(func):
+    # a hack to make at least ffi.typeof(builtin_function) work,
+    # if the builtin function was obtained by 'vengine_cpy'.
+    import sys
+    try:
+        module = sys.modules[func.__module__]
+        ffi = module._cffi_original_ffi
+        types_of_builtin_funcs = module._cffi_types_of_builtin_funcs
+        tp = types_of_builtin_funcs[func]
+    except (KeyError, AttributeError, TypeError):
+        return None
+    else:
+        with ffi._lock:
+            return ffi._get_cached_btype(tp)