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Your IP : 18.221.160.29
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
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):
"""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.
"""
self._cdef(csource, override=override, packed=packed)
def embedding_api(self, csource, packed=False):
self._cdef(csource, packed=packed, 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.
"""
assert isinstance(name, basestring) or name is None
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, python_buffer, require_writable=False):
"""Return a <cdata 'char[]'> that points 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.
"""
return self._backend.from_buffer(self.BCharA, 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 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 = "python27"
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 distutils 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 distutils_extension(self, tmpdir='build', verbose=True):
from distutils.dir_util 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, **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, **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 name is None:
if sys.platform != "win32":
return backend.load_library(None, 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 libname is not None:
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)