simon-hibbs · June 27, 2019 20:15 · Dec 4, 2016
diff --git a/objc_util.py b/objc_util.py
@@ -0,0 +1,1203 @@
+# coding: utf-8
+
+__all__ = ['c', 'LP64', 'CGFloat', 'NSInteger', 'NSUInteger', 'NSNotFound', 'NSUTF8StringEncoding', 'NS_UTF8', 'CGPoint', 'CGSize', 'CGVector', 'CGRect', 'CGAffineTransform', 'UIEdgeInsets', 'NSRange', 'sel', 'ObjCClass', 'ObjCInstance', 'ObjCClassMethod', 'ObjCInstanceMethod', 'NSObject', 'NSArray', 'NSMutableArray', 'NSDictionary', 'NSMutableDictionary', 'NSSet', 'NSMutableSet', 'NSString', 'NSMutableString', 'NSData', 'NSMutableData', 'NSNumber', 'NSURL', 'NSEnumerator', 'NSThread', 'NSBundle', 'UIColor', 'UIImage', 'UIBezierPath', 'UIApplication', 'UIView', 'ObjCBlock', 'ns', 'nsurl', 'retain_global', 'release_global', 'on_main_thread', 'create_objc_class',
+'Structure', 'sizeof', 'byref', 'c_void_p', 'c_char', 'c_byte', 'c_char_p', 'c_double', 'c_float', 'c_int', 'c_longlong', 'c_short', 'c_bool', 'c_long', 'c_int32', 'c_ubyte', 'c_uint', 'c_ushort', 'c_ulong', 'c_ulonglong', 'POINTER', 'pointer', 'load_framework', 'nsdata_to_bytes', 'uiimage_to_png']
+
+try:
+	import ctypes
+except ImportError:
+	raise NotImplementedError("objc_util requires ctypes, which doesn't seem to be available.")
+
+from ctypes import Structure, sizeof, byref, cdll, pydll, c_void_p, c_char, c_byte, c_char_p, c_double, c_float, c_int, c_longlong, c_short, c_bool, c_long, c_int32, c_ubyte, c_uint, c_ushort, c_ulong, c_ulonglong, POINTER, pointer
+import re
+import sys
+import os
+import itertools
+import ui
+import weakref
+import string
+import pyparsing as pp
+import inspect
+import functools
+
+PY3 = sys.version_info[0] >= 3
+
+if PY3:
+	basestring = str
+	string_lowercase = string.ascii_lowercase
+	xrange = range
+	long = int
+else:
+	bytes = str
+	string_lowercase = string.lowercase
+
+def filter_list(*args, **kwargs):
+	if PY3:
+		return list(filter(*args, **kwargs))
+	return filter(*args, **kwargs)
+
+LP64 = (sizeof(c_void_p) == 8)
+
+_retained_globals = []
+_cached_classes = {}
+_cached_instances = weakref.WeakValueDictionary()
+_tracefunc = None
+
+c = cdll.LoadLibrary(None)
+
+class_getName = c.class_getName
+class_getName.restype = c_char_p
+class_getName.argtypes = [c_void_p]
+
+class_getSuperclass = c.class_getSuperclass
+class_getSuperclass.restype = c_void_p
+class_getSuperclass.argtypes = [c_void_p]
+
+class_addMethod = c.class_addMethod
+class_addMethod.restype = c_bool
+class_addMethod.argtypes = [c_void_p, c_void_p, c_void_p, c_char_p]
+
+class_getInstanceMethod = c.class_getInstanceMethod
+class_getInstanceMethod.restype = c_void_p
+class_getInstanceMethod.argtypes = [c_void_p, c_void_p]
+
+class_getClassMethod = c.class_getClassMethod
+class_getClassMethod.restype = c_void_p
+class_getClassMethod.argtypes = [c_void_p, c_void_p]
+
+objc_allocateClassPair = c.objc_allocateClassPair
+objc_allocateClassPair.restype = c_void_p
+objc_allocateClassPair.argtypes = [c_void_p, c_char_p, c_int]
+
+objc_registerClassPair = c.objc_registerClassPair
+objc_registerClassPair.restype = None
+objc_registerClassPair.argtypes = [c_void_p]
+
+objc_getClass = c.objc_getClass
+objc_getClass.argtypes = [c_char_p]
+objc_getClass.restype = c_void_p
+
+objc_getClassList = c.objc_getClassList
+objc_getClassList.restype = c_int
+objc_getClassList.argtypes = [c_void_p, c_int]
+
+method_getTypeEncoding = c.method_getTypeEncoding
+method_getTypeEncoding.argtypes = [c_void_p]
+method_getTypeEncoding.restype = c_char_p
+
+sel_getName = c.sel_getName
+sel_getName.restype = c_char_p
+sel_getName.argtypes = [c_void_p]
+
+sel_registerName = c.sel_registerName
+sel_registerName.restype = c_void_p
+sel_registerName.argtypes = [c_char_p]
+
+object_getClass = c.object_getClass
+object_getClass.argtypes = [c_void_p]
+object_getClass.restype = c_void_p
+
+class_copyMethodList = c.class_copyMethodList
+class_copyMethodList.restype = ctypes.POINTER(c_void_p)
+class_copyMethodList.argtypes = [c_void_p, ctypes.POINTER(ctypes.c_uint)]
+
+class_getProperty = c.class_getProperty
+class_getProperty.restype = c_void_p
+class_getProperty.argtypes = [c_void_p, c_char_p]
+
+property_getAttributes = c.property_getAttributes
+property_getAttributes.argtypes = [c_void_p]
+property_getAttributes.restype = c_char_p
+
+method_getName = c.method_getName
+method_getName.restype = c_void_p
+method_getName.argtypes = [c_void_p]
+
+class objc_method_description (Structure):
+	_fields_ = [('sel', c_void_p), ('types', c_char_p)]
+
+objc_getProtocol = c.objc_getProtocol
+objc_getProtocol.restype = c_void_p
+objc_getProtocol.argtypes = [c_char_p]
+
+protocol_getMethodDescription = c.protocol_getMethodDescription
+protocol_getMethodDescription.restype = objc_method_description
+protocol_getMethodDescription.argtypes = [c_void_p, c_void_p, c_bool, c_bool]
+
+objc_msgSend = c.objc_msgSend
+if not LP64:
+	objc_msgSend_stret = c.objc_msgSend_stret
+
+free = c.free
+free.argtypes = [c_void_p]
+free.restype = None
+
+CGFloat = c_double if LP64 else c_float
+NSInteger = c_long if LP64 else c_int
+NSUInteger = c_ulong if LP64 else c_uint
+
+if PY3:
+	NSNotFound = sys.maxsize
+else:
+	NSNotFound = sys.maxint
+
+NSUTF8StringEncoding = 4
+NS_UTF8 = NSUTF8StringEncoding
+
+class CGPoint (Structure):
+	_fields_ = [('x', CGFloat), ('y', CGFloat)]
+
+class CGSize (Structure):
+	_fields_ = [('width', CGFloat), ('height', CGFloat)]
+
+class CGVector (Structure):
+	_fields_ = [('dx', CGFloat), ('dy', CGFloat)]
+
+class CGRect (Structure):
+	_fields_ = [('origin', CGPoint), ('size', CGSize)]
+
+class CGAffineTransform (Structure):
+	_fields_ = [('a', CGFloat), ('b', CGFloat), ('c', CGFloat), ('d', CGFloat), ('tx', CGFloat), ('ty', CGFloat)]
+
+class UIEdgeInsets (Structure):
+	_fields_ = [('top', CGFloat), ('left', CGFloat), ('bottom', CGFloat), ('right', CGFloat)]
+
+class NSRange (Structure):
+	_fields_ = [('location', NSUInteger), ('length', NSUInteger)]
+
+# c.f. https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html
+type_encodings = {'c': c_byte, 'i': c_int, 's': c_short, 'l': c_int32, 'q': c_longlong,
+	'C': c_ubyte, 'I': c_uint, 'S': c_ushort, 'L': c_ulong, 'Q': c_ulonglong,
+	'f': c_float, 'd': c_double, 'B': c_bool, 'v': None, '*': c_char_p,
+	'@': c_void_p, '#': c_void_p, ':': c_void_p,
+	'{CGPoint}': CGPoint, '{CGSize}': CGSize, '{CGRect}': CGRect, '{CGVector}': CGVector,
+	'{CGAffineTransform}': CGAffineTransform, '{UIEdgeInsets}': UIEdgeInsets, '{_NSRange}': NSRange,
+	'?': c_void_p, '@?': c_void_p
+}
+
+def split_encoding(encoding):
+	# This function is mostly copied from pybee's rubicon.objc
+	# (https://github.com/pybee/rubicon-objc)
+	# License: https://github.com/pybee/rubicon-objc/blob/master/LICENSE
+	type_encodings = []
+	braces, brackets = 0, 0
+	typecode = ''
+	if PY3 and isinstance(encoding, bytes):
+		encoding = encoding.decode('ascii')
+	for c in encoding:
+		if c == '{':
+			if typecode and typecode[-1:] != '^' and braces == 0 and brackets == 0:
+				type_encodings.append(typecode)
+				typecode = ''
+			typecode += c
+			braces += 1
+		elif c == '}':
+			typecode += c
+			braces -= 1
+		elif c == '[':
+			if typecode and typecode[-1:] != '^' and braces == 0 and brackets == 0:
+				type_encodings.append(typecode)
+				typecode = ''
+			typecode += c
+			brackets += 1
+		elif c == ']':
+			typecode += c
+			brackets -= 1
+		elif braces or brackets:
+			typecode += c
+		elif c in string.digits:
+			pass
+		elif c in 'rnNoORV':
+			pass
+		elif c in '^cislqCISLQfdBv*@#:b?':
+			if c == '?' and typecode[-1:] == '@':
+				typecode += c
+			elif typecode and typecode[-1:] == '^':
+				typecode += c
+			else:
+				if typecode:
+					type_encodings.append(typecode)
+				typecode = c
+	if typecode:
+		type_encodings.append(typecode)
+	return type_encodings
+
+
+def struct_from_tuple(cls, t):
+	args = []
+	for i, field_value in enumerate(t):
+		if isinstance(field_value, tuple):
+			args.append(struct_from_tuple(cls._fields_[i][1], field_value))
+		else:
+			args.append(field_value)
+	return cls(*args)
+
+def _struct_class_from_fields(fields):
+	class AnonymousStructure (Structure):
+		from_tuple = classmethod(struct_from_tuple)
+	struct_fields = []
+	for i, field in enumerate(fields):
+		if isinstance(field, tuple):
+			struct_fields.append(field)
+		else:
+			struct_fields.append((string_lowercase[i], _struct_class_from_fields(field)))
+			i += 1
+	AnonymousStructure._fields_ = struct_fields
+	return AnonymousStructure
+
+def _list_to_fields(result):
+	fields = []
+	i = 0
+	if isinstance(result, basestring):
+		for char in split_encoding(result):
+			c_type = parse_types(char)[0]
+			fields.append((string_lowercase[i], c_type))
+			i += 1
+	else:
+		if len(result) == 1:
+			return _list_to_fields(result[0])
+		for r in result:
+			fields.append(_list_to_fields(r))
+	return fields
+
+def _result_to_list(result):
+	struct_result = []
+	for member in result:
+		if isinstance(member, basestring):
+			struct_result.append(member)
+		else:
+			struct_result.append(_result_to_list([member[2]]))
+	return struct_result
+
+_enclosed = pp.Forward()
+_nested_curlies = pp.nestedExpr('{', '}', content=_enclosed)
+_enclosed << (pp.Word(pp.alphas + '?_' + pp.nums) | '=' | _nested_curlies)
+
+def parse_struct(encoding):
+	comps = _enclosed.parseString(encoding).asList()[0]
+	struct_name = comps[0]
+	struct_members = comps[2:]
+	fields = _list_to_fields(_result_to_list(struct_members))
+	struct_class = _struct_class_from_fields(fields)
+	struct_class.__name__ = (struct_name + '_Structure').replace('?', '_')
+	return struct_class
+
+_cached_parse_types_results = {}
+
+def parse_types(type_encoding):
+	'''Take an Objective-C type encoding string and convert it to a tuple of (restype, argtypes) appropriate for objc_msgSend()'''
+	cached_result = _cached_parse_types_results.get(type_encoding)
+	if cached_result:
+		return cached_result
+	def get_type_for_code(enc_str):
+		if enc_str.startswith('{'):
+			struct_name = enc_str[0:enc_str.find('=')] + '}'
+			if struct_name in type_encodings:
+				return type_encodings[struct_name]
+			else:
+				return parse_struct(enc_str)
+		if enc_str[0] in 'rnNoORV': #const, in, inout... don't care about these
+			enc_str = enc_str[1:]
+		if enc_str[0] == '^':
+			if re.match(r'\^\{\w+=#?\}', enc_str):
+				return c_void_p # pointer to opaque type, e.g. CGPathRef, CGImageRef...
+			else:
+				return POINTER(get_type_for_code(enc_str[1:]))
+		if enc_str[0] == '[': #array
+			return c_void_p
+		try:
+			t = type_encodings[enc_str]
+			return t
+		except KeyError:
+			raise NotImplementedError('Unsupported type encoding (%s)' % (enc_str,))
+	encoded_types = filter_list(lambda x: bool(x), split_encoding(type_encoding))
+	encoded_argtypes = encoded_types[3:]
+	argtypes = [get_type_for_code(x) for x in encoded_argtypes]
+	restype = get_type_for_code(encoded_types[0])
+	cached_result = (restype, [c_void_p, c_void_p] + argtypes, encoded_argtypes)
+	_cached_parse_types_results[type_encoding] = cached_result
+	return cached_result
+
+def sel(sel_name):
+	'''Convenience function to convert a string to a selector'''
+	if PY3 and isinstance(sel_name, str):
+		sel_name = sel_name.encode('ascii')
+	return sel_registerName(sel_name)
+
+def _first_letter_cap(s):
+	if not s:
+		return ''
+	return s[0].upper() + s[1:]
+
+def get_possible_method_names(name, args, kwargs):
+	# Return a list of possible ObjC method names for a given combination of arguments. Basically all permutations of keyword args...
+	if '_' in name:
+		# Should never actually happen...
+		return [(name, [])]
+	if name.endswith('With'):
+		name = name[:-4]
+	possible_names = []
+	if len(args) == 0 and len(kwargs) == 0:
+		possible_names.append((name, []))
+	elif len(kwargs) == 0 and len(args) == 1:
+		possible_names.append((name + '_', []))
+	else:
+		permutations = itertools.permutations(kwargs.keys())
+		found_methods = []
+		for perm in permutations:
+			name1 = name + '_' + '_'.join(perm) + '_'
+			possible_names.append((name1, list(perm)))
+			if len(args) == 0:
+				name2 = name + 'With%s_' % (_first_letter_cap(perm[0]),) + '_'.join(perm[1:])
+				if len(perm) > 1:
+					name2 += '_'
+				possible_names.append((name2, list(perm)))
+				name3 = name + _first_letter_cap(perm[0]) + '_' + '_'.join(perm[1:])
+				if len(perm) > 1:
+					name3 += '_'
+				possible_names.append((name3, list(perm)))
+
+	return possible_names
+
+def resolve_cls_method(cls, name, args, kwargs):
+	# Return (method_name, ordered_kwargs), or raise an AttributeError if either no method could be found, or if the mapping was ambiguous.
+	kwargs_copy = dict(kwargs)
+	if 'argtypes' in kwargs_copy:
+		del kwargs_copy['argtypes']
+	if 'restype' in kwargs_copy:
+		del kwargs_copy['restype']
+	possible_names = get_possible_method_names(name, args, kwargs_copy)
+	valid_names = []
+	for method_name, kwarg_order in possible_names:
+		try:
+			meth = ObjCClassMethod(cls, method_name)
+			valid_names.append((method_name, kwarg_order))
+		except AttributeError:
+			pass
+	if len(valid_names) == 1:
+		return valid_names[0]
+	elif len(valid_names) == 0:
+		raise AttributeError('No method found for %s' % (name,))
+	else:
+		raise AttributeError('Method name is ambiguous')
+
+def resolve_instance_method(obj, name, args, kwargs):
+	# Return (method_name, ordered_kwargs), or raise an AttributeError if either no method could be found, or if the mapping was ambiguous.
+	kwargs_copy = dict(kwargs)
+	if 'argtypes' in kwargs_copy:
+		del kwargs_copy['argtypes']
+	if 'restype' in kwargs_copy:
+		del kwargs_copy['restype']
+	possible_names = get_possible_method_names(name, args, kwargs_copy)
+	valid_names = []
+	for method_name, kwarg_order in possible_names:
+		try:
+			possibly_property = len(args) == 0 and len(kwargs) == 0
+			meth = ObjCInstanceMethod(obj, method_name, allow_property=possibly_property)
+			valid_names.append((method_name, kwarg_order))
+		except AttributeError:
+			pass
+	if len(valid_names) == 1:
+		return valid_names[0]
+	elif len(valid_names) == 0:
+		raise AttributeError('No method found for %s' % (name,))
+	else:
+		raise AttributeError('Method name is ambiguous')
+
+class ObjCClass (object):
+	'''Wrapper for a pointer to an Objective-C class; acts as a proxy for calling Objective-C class methods. Method calls are converted to Objective-C messages on-the-fly -- this is done by replacing underscores in the method name with colons in the selector name, and using the selector and arguments for a call to the low-level objc_msgSend function in the Objective-C runtime. For example, calling `NSDictionary.dictionaryWithObject_forKey_(obj, key)` (Python) is translated to `[NSDictionary dictionaryWithObject:obj forKey:key]` (Objective-C). If a method call returns an Objective-C object, it is wrapped in an ObjCInstance, so calls can be chained (ObjCInstance uses an equivalent proxy mechanism).'''
+	def __new__(cls, name):
+		if PY3 and isinstance(name, str):
+			name = name.encode('ascii')
+
+		# Memoize classes by name (get identical object every time):
+		cached_class = _cached_classes.get(name)
+		if cached_class:
+			return cached_class
+		cached_class = super(ObjCClass, cls).__new__(cls)
+		_cached_classes[name] = cached_class
+		return cached_class
+
+	def __init__(self, name):
+		if PY3 and isinstance(name, str):
+			name = name.encode('ascii')
+
+		self.ptr = objc_getClass(name)
+		if self.ptr is None:
+			raise ValueError('no Objective-C class named \'%s\' found' % (name,))
+		self._as_parameter_ = self.ptr
+		self.class_name = name
+		self._cached_methods = {}
+
+	def __str__(self):
+		return '<ObjCClass: %s>' % (self.class_name,)
+
+	def __eq__(self, other):
+		return isinstance(other, ObjCClass) and self.class_name == other.class_name
+
+	def __getattr__(self, attr):
+		cached_method = self._cached_methods.get(attr, None)
+		if not cached_method:
+			if '_' in attr:
+				# Old method call syntax
+				cached_method = ObjCClassMethod(self, attr)
+			else:
+				# New syntax, actual method resolution is done at call time
+				cached_method = ObjCClassMethodProxy(self, attr)
+			self._cached_methods[attr] = cached_method
+		return cached_method
+
+	def __dir__(self):
+		objc_class_ptr = object_getClass(self.ptr)
+		py_methods = []
+		while objc_class_ptr is not None:
+			num_methods = c_uint(0)
+			method_list_ptr = class_copyMethodList(objc_class_ptr, byref(num_methods))
+			for i in xrange(num_methods.value):
+				selector = method_getName(method_list_ptr[i])
+				sel_name = sel_getName(selector)
+				if PY3:
+					sel_name = sel_name.decode('ascii')
+				py_method_name = sel_name.replace(':', '_')
+				if '.' not in py_method_name:
+					py_methods.append(py_method_name)
+			free(method_list_ptr)
+			# Walk up the class hierarchy to add methods from superclasses:
+			objc_class_ptr = class_getSuperclass(objc_class_ptr)
+			if objc_class_ptr == object_getClass(NSObject):
+				# Don't list all methods from NSObject (too much cruft from categories)
+				py_methods += NSObject_class_methods
+				break
+		py_methods = sorted(set(py_methods))
+		return py_methods
+
+	@classmethod
+	def get_names(cls, prefix=None):
+		num_classes = objc_getClassList(None, 0)
+		buffer = (c_void_p * num_classes)()
+		objc_getClassList(buffer, num_classes)
+		class_names = []
+		for i in xrange(num_classes):
+			n = class_getName(buffer[i])
+			if PY3:
+				n = n.decode('ascii')
+			class_names.append(n)
+		filtered_list = class_names if prefix is None else filter_list(lambda x: x.startswith(prefix), class_names)
+		return sorted(filtered_list)
+
+	@classmethod
+	def create(cls, *args, **kwargs):
+		return create_objc_class(*args, **kwargs)
+
+
+class ObjCIterator (object):
+	'''Wrapper for an NSEnumerator object -- this is used for supporting `for ... in` iteration for Objective-C collection types (NSArray, NSDictionary, NSSet).'''
+	def __init__(self, obj):
+		self.enumerator = obj.objectEnumerator()
+
+	def __iter__(self):
+		return self
+
+	def next(self):
+		next_obj = self.enumerator.nextObject()
+		if next_obj is None:
+			raise StopIteration()
+		return next_obj
+
+	def __next__(self):
+		return self.next()
+
+class ObjCInstance (object):
+	'''Wrapper for a pointer to an Objective-C instance; acts as a proxy for sending messages to the object. Method calls are converted to Objective-C messages on-the-fly -- this is done by replacing underscores in the method name with colons in the selector name, and using the selector and arguments for a call to the low-level objc_msgSend function in the Objective-C runtime. For example, calling `obj.setFoo_withBar_(foo, bar)` (Python) is translated to `[obj setFoo:foo withBar:bar]` (Objective-C). If a method call returns an Objective-C object, it is also wrapped in an ObjCInstance, so calls can be chained.'''
+
+	def __new__(cls, ptr):
+		# If there is already an instance that wraps this pointer, return the same object...
+		# This makes it a little easier to put auxiliary data into the instance (e.g. to use in an ObjC callback)
+		# Note however that a new instance may be created for the same underlying ObjC object if the last instance gets garbage-collected.
+		if isinstance(ptr, ObjCInstance):
+			return ptr
+		if hasattr(ptr, '_objc_ptr'):
+			ptr = ptr._objc_ptr
+		if isinstance(ptr, c_void_p):
+			ptr = ptr.value
+		cached_instance = _cached_instances.get(ptr)
+		if cached_instance is not None:
+			return cached_instance
+		objc_instance = super(ObjCInstance, cls).__new__(cls)
+		_cached_instances[ptr] = objc_instance
+		objc_instance.ptr = ptr
+		objc_instance._as_parameter_ = ptr
+		objc_instance._cached_methods = {}
+		objc_instance.weakrefs = weakref.WeakValueDictionary()
+		if ptr:
+			# Retain the ObjC object, so it doesn't get freed while a pointer to it exists:
+			objc_instance.retain(restype=c_void_p, argtypes=[])
+		return objc_instance
+
+	def __str__(self):
+		objc_msgSend = c['objc_msgSend']
+		objc_msgSend.argtypes = [c_void_p, c_void_p]
+		objc_msgSend.restype = c_void_p
+		desc = objc_msgSend(self.ptr, sel('description'))
+		objc_msgSend.argtypes = [c_void_p, c_void_p]
+		objc_msgSend.restype = c_char_p
+		desc_str = objc_msgSend(desc, sel('UTF8String'))
+		if PY3:
+			return desc_str.decode('utf-8')
+		return desc_str
+
+	def _get_objc_classname(self):
+		return class_getName(object_getClass(self.ptr))
+
+	def __repr__(self):
+		return '<%s: %s>' % (self._get_objc_classname(), str(self))
+
+	def __eq__(self, other):
+		return isinstance(other, ObjCInstance) and self.ptr == other.ptr
+
+	def __hash__(self):
+		return hash(self.ptr)
+
+	def __iter__(self):
+		if any(self.isKindOfClass_(c) for c in (NSArray, NSDictionary, NSSet)):
+			return ObjCIterator(self)
+		raise TypeError('%s is not iterable' % (self._get_objc_classname(),))
+
+	def __nonzero__(self):
+		try:
+			return len(self) != 0
+		except TypeError:
+			return self.ptr != None
+
+	def __bool__(self):
+		return self.__nonzero__()
+
+	def __len__(self):
+		if any(self.isKindOfClass_(c) for c in (NSArray, NSDictionary, NSSet)):
+			return self.count()
+		raise TypeError('object of type \'%s\' has no len()' % (self._get_objc_classname(),))
+
+	def __getitem__(self, key):
+		if self.isKindOfClass_(NSArray):
+			if not isinstance(key, (int, long)):
+				raise TypeError('array indices must be integers not %s' % (type(key),))
+			array_length = self.count()
+			if key < 0:
+				# a[-1] is equivalent to a[len(a) - 1]
+				key = array_length + key
+			if key < 0 or key >= array_length:
+				raise IndexError('array index out of range')
+			return self.objectAtIndex_(key)
+		elif self.isKindOfClass_(NSDictionary):
+			# allow to use Python strings as keys, convert to NSString implicitly:
+			ns_key = ns(key)
+			# NOTE: Unlike Python dicts, NSDictionary returns nil (None) for keys that don't exist.
+			return self.objectForKey_(ns_key)
+		raise TypeError('%s does not support __getitem__' % (self._get_objc_classname(),))
+
+	def __delitem__(self, key):
+		if self.isKindOfClass_(NSMutableArray):
+			if not isinstance(key, (int, long)):
+				raise TypeError('array indices must be integers not %s' % (type(key),))
+			array_length = self.count()
+			if key < 0:
+				# a[-1] is equivalent to a[len(a) - 1]
+				key = array_length + key
+			if key < 0 or key >= array_length:
+				raise IndexError('array index out of range')
+			self.removeObjectAtIndex_(key)
+		elif self.isKindOfClass_(NSMutableDictionary):
+			ns_key = ns(key)
+			return self.removeObjectForKey_(ns_key)
+		else:
+			raise TypeError('%s does not support __delitem__' % (self._get_objc_classname(),))
+
+	def __setitem__(self, key, value):
+		if self.isKindOfClass_(NSMutableArray):
+			if not isinstance(key, (int, long)):
+				raise TypeError('array indices must be integers not %s' % (type(key),))
+			array_length = self.count()
+			if key < 0:
+				# a[-1] is equivalent to a[len(a) - 1]
+				key = array_length + key
+			if key < 0 or key >= array_length:
+				raise IndexError('array index out of range')
+			self.replaceObjectAtIndex_withObject_(key, ns(value))
+		elif self.isKindOfClass_(NSMutableDictionary):
+			self.setObject_forKey_(ns(value), ns(key))
+		else:
+			raise TypeError('%s does not support __setitem__' % (self._get_objc_classname(),))
+
+	def __getattr__(self, attr):
+		cached_method = self._cached_methods.get(attr, None)
+		if not cached_method:
+			if '_' in attr:
+				# Old method call syntax
+				cached_method = ObjCInstanceMethod(self, attr)
+			else:
+				# New syntax, actual method resolution is done at call time
+				cached_method = ObjCInstanceMethodProxy(self, attr)
+			self._cached_methods[attr] = cached_method
+		return cached_method
+
+	def __setattr__(self, name, value):
+		if name in ('ptr', 'weakrefs', '_cached_methods', '_as_parameter_'):
+			self.__dict__[name] = value
+			return
+		try:
+			setter_method = getattr(self, 'set%s%s_' % (name[0].upper(), name[1:]))
+			setter_method(value)
+		except AttributeError:
+			self.__dict__[name] = value
+
+	def __dir__(self):
+		objc_class_ptr = object_getClass(self.ptr)
+		py_methods = []
+		while objc_class_ptr is not None:
+			num_methods = c_uint(0)
+			method_list_ptr = class_copyMethodList(objc_class_ptr, byref(num_methods))
+			for i in xrange(num_methods.value):
+				selector = method_getName(method_list_ptr[i])
+				sel_name = sel_getName(selector)
+				if PY3:
+					sel_name = sel_name.decode('ascii')
+				py_method_name = sel_name.replace(':', '_')
+				if '.' not in py_method_name:
+					py_methods.append(py_method_name)
+			free(method_list_ptr)
+			# Walk up the class hierarchy to add methods from superclasses:
+			objc_class_ptr = class_getSuperclass(objc_class_ptr)
+			if objc_class_ptr == NSObject.ptr:
+				# Don't list all NSObject methods (too much cruft from categories...)
+				py_methods += NSObject_instance_methods
+				break
+		return sorted(set(py_methods))
+
+	def __del__(self):
+		# Release the ObjC object's memory:
+		objc_msgSend = c['objc_msgSend']
+		objc_msgSend.argtypes = [c_void_p, c_void_p]
+		objc_msgSend.restype = None
+		objc_msgSend(self.ptr, sel('release'))
+		#self.release(restype=None, argtypes=[])
+
+def _get_possible_selector_names(method_name):
+	# Generate all possible selector names from a Python method name. For most methods, this isn't necessary,
+	# and the selector is generated simply by replacing underscores with colons, but in case the selector also
+	# contains underscores, the mapping is ambiguous, so all permutations of colons and underscores need to be checked.
+	izip_longest = itertools.zip_longest if PY3 else itertools.izip_longest
+	return [''.join([x+y for x, y in izip_longest(method_name.split('_'), s, fillvalue='')]) for s in [''.join(x) for x in itertools.product(':_', repeat=len(method_name.split('_'))-1)]]
+
+def _auto_wrap(arg, typecode, argtype):
+	'''Helper function for `ObjCInstance/ClassMethod.__call__`'''
+	if typecode == '@' or typecode.startswith('^{'):
+		return ns(arg)
+	elif typecode == ':' and isinstance(arg, basestring):
+		# if a selector is expected, also allow a string:
+		return sel(arg)
+	elif issubclass(argtype, Structure) and isinstance(arg, tuple):
+		# Automatically convert tuples to structs
+		return struct_from_tuple(argtype, arg)
+	return arg
+
+
+class ObjCClassMethodProxy (object):
+	'''A proxy for an ObjCClassMethod that is resolved to an actual method when calling it. A proxy may represent different methods, depending on the keyword arguments that are passed (and used to construct an ObjC selector from the call).'''
+	def __init__(self, cls, name):
+		self.cls = weakref.ref(cls)
+		self.name = name
+		# Determining the method for a given combination of args/kwargs can be expensive, so it's cached by 'num_args/sorted_kwarg_keys'. The cache contains a pair of (ObjCClassMethod, ordered_kwarg_keys).
+		self.method_cache = {}
+
+	def __call__(self, *args, **kwargs):
+		cls = self.cls()
+		if cls is None:
+			# If the class doesn't exist anymore, don't do anything
+			# (this is unlikely to happen in practice)
+			return
+		cache_key = '%i/' % (len(args),) + ','.join(sorted(kwargs.keys()))
+		cached = self.method_cache.get(cache_key)
+		if cached:
+			method, kwarg_order = cached
+		else:
+			method_name, kwarg_order = resolve_cls_method(cls, self.name, args, kwargs)
+			method = ObjCClassMethod(cls, method_name)
+			self.method_cache[cache_key] = (method, kwarg_order)
+		ordered_args = list(args) + [kwargs[key] for key in kwarg_order]
+		# Pass through restype and argtypes keyword args:
+		kw = {k: kwargs[k] for k in ('restype', 'kwargs') if k in kwargs}
+		return method(*ordered_args, **kw)
+
+
+class ObjCClassMethod (object):
+	'''Wrapper for an Objective-C class method. ObjCClass generates these objects automatically when accessing an attribute, you typically don't need use this class directly.'''
+	def __init__(self, cls, method_name):
+		self.cls = cls
+		self.sel_name = method_name.replace('_', ':')
+		method = class_getClassMethod(cls.ptr, sel(self.sel_name))
+		if not method:
+			# Couldn't find a method, try all combinations of underscores and colons...
+			# For selectors that contain underscores, the mapping from Python method name to selector name is ambiguous.
+			possible_selector_names = _get_possible_selector_names(method_name)
+			for possible_sel_name in possible_selector_names:
+				method = class_getClassMethod(cls.ptr, sel(possible_sel_name))
+				if method:
+					self.sel_name = possible_sel_name
+					break
+		if method:
+			self.method = method
+			self.encoding = method_getTypeEncoding(method)
+		else:
+			raise AttributeError('No class method found for selector "%s"' % (self.sel_name))
+
+	def __call__(self, *args, **kwargs):
+		cls = self.cls
+		if cls is None:
+			return
+		type_encoding = self.encoding
+		try:
+			argtypes = kwargs['argtypes']
+			restype = kwargs['restype']
+			argtypes = [c_void_p, c_void_p] + argtypes
+		except KeyError:
+			restype, argtypes, argtype_encodings = parse_types(type_encoding)
+			if len(args) != len(argtypes) - 2:
+				raise TypeError('expected %i arguments, got %i' % (len(argtypes) - 2, len(args)))
+			# Automatically convert Python strings to NSString etc. for object arguments
+			# (this is a no-op for arguments that are already `ObjCInstance` objects):
+			args = tuple(_auto_wrap(a, argtype_encodings[i], argtypes[i+2]) for i, a in enumerate(args))
+		objc_msgSend = c['objc_msgSend']
+		objc_msgSend.argtypes = argtypes
+		objc_msgSend.restype = restype
+		res = objc_msgSend(cls, sel(self.sel_name), *args)
+		return_type_enc = chr(type_encoding[0]) if PY3 else type_encoding[0]
+		if res and return_type_enc == '@':
+			return ObjCInstance(res)
+		return res
+
+class ObjCInstanceMethodProxy (object):
+	'''A proxy for an ObjCInstanceMethod that is resolved to an actual method when calling it. A proxy may represent different methods, depending on the keyword arguments that are passed (and used to construct an ObjC selector from the call).'''
+	def __init__(self, obj, name):
+		self.obj = weakref.ref(obj)
+		self.name = name
+		# Determining the method for a given combination of args/kwargs can be expensive, so it's cached by 'num_args/sorted_kwarg_keys'. The cache contains a pair of (ObjCClassMethod, ordered_kwarg_keys).
+		self.method_cache = {}
+
+	def __call__(self, *args, **kwargs):
+		obj = self.obj()
+		if obj is None:
+			# If the instance doesn't exist anymore, don't do anything
+			# (this is unlikely to happen in practice)
+			return
+		cache_key = '%i/' % (len(args),) + ','.join(sorted(kwargs.keys()))
+		cached = self.method_cache.get(cache_key)
+		if cached:
+			method, kwarg_order = cached
+		else:
+			method_name, kwarg_order = resolve_instance_method(obj, self.name, args, kwargs)
+			method = ObjCInstanceMethod(obj, method_name)
+			self.method_cache[cache_key] = (method, kwarg_order)
+		ordered_args = list(args) + [kwargs[key] for key in kwarg_order]
+		# Pass through restype and argtypes keyword args:
+		kw = {k: kwargs[k] for k in ('restype', 'kwargs') if k in kwargs}
+		return method(*ordered_args, **kw)
+
+
+class ObjCInstanceMethod (object):
+	'''Wrapper for an Objective-C instance method. ObjCInstance generates these objects automatically when accessing an attribute, you typically don't need to use this class directly.'''
+	def __init__(self, obj, method_name, allow_property=True):
+		self.obj = obj
+		objc_class = object_getClass(obj.ptr)
+		self.encoding = None
+		method = None
+		self.sel_name = method_name.replace('_', ':')
+		method = class_getInstanceMethod(objc_class, sel(self.sel_name))
+		self._objc_msgSend = None
+		if not method and '_' in method_name:
+			# Couldn't find a method, try all combinations of underscores and colons...
+			# For selectors that contain underscores, the mapping from Python method name to selector name is ambiguous.
+			possible_selector_names = _get_possible_selector_names(method_name)
+			for possible_sel_name in possible_selector_names:
+				method = class_getInstanceMethod(objc_class, sel(possible_sel_name))
+				if method:
+					self.sel_name = possible_sel_name
+					break
+		if allow_property and not method and ((method_name.startswith('set') and self.sel_name.endswith(':')) or self.sel_name.find(':') == -1):
+			#Looks like it could be a property
+			prop_name = method_name
+			if method_name.startswith('set'):
+				prop_name = method_name[3].lower() + method_name[4:-1]
+			else:
+				prop_name = method_name
+			if PY3 and isinstance(prop_name, str):
+				prop_name = prop_name.encode('ascii')
+			prop = class_getProperty(objc_class, prop_name)
+			if prop:
+				#TODO: Check if the property is read-only when a setter is used...
+				prop_attrs = property_getAttributes(prop)
+				if PY3:
+					prop_attrs = prop_attrs.decode('ascii')
+				prop_type_encoding = re.search('T(.+?),', prop_attrs).group(1)
+				if method_name.startswith('set'):
+					#NOTE: The offsets/sizes are obviously incorrect... (should still work though)
+					self.encoding = 'v0@0:0' + prop_type_encoding + '0'
+					if PY3:
+						self.encoding = self.encoding.encode('ascii')
+					sel_name_match = re.search(r'S(.*?)(:?,.*?|$)', prop_attrs)
+					if sel_name_match:
+						self.sel_name = sel_name_match.group(1)
+				else:
+					self.encoding = prop_type_encoding + '0@0:0'
+					if PY3:
+						self.encoding = self.encoding.encode('ascii')
+					sel_name_match = re.search(r'G(.*?)(:?,.*?|$)', prop_attrs)
+					if sel_name_match:
+						self.sel_name = sel_name_match.group(1)
+		if not self.encoding and method:
+			self.method = method
+			self.encoding = method_getTypeEncoding(method)
+		elif not self.encoding:
+			raise AttributeError('No method found for selector "%s"' % (self.sel_name))
+
+	def __call__(self, *args, **kwargs):
+		obj = self.obj
+		if obj is None:
+			return
+		type_encoding = self.encoding
+		try:
+			argtypes = kwargs['argtypes']
+			restype = kwargs['restype']
+			argtypes = [c_void_p, c_void_p] + argtypes
+		except KeyError:
+			restype, argtypes, argtype_encodings = parse_types(type_encoding)
+			if len(args) != len(argtypes) - 2:
+				raise TypeError('expected %i arguments, got %i' % (len(argtypes) - 2, len(args)))
+			# Automatically convert Python strings to NSString etc. for object arguments
+			# (this is a no-op for arguments that are already `ObjCInstance` objects):
+			args = tuple(_auto_wrap(a, argtype_encodings[i], argtypes[i+2]) for i, a in enumerate(args))
+
+		if not LP64 and restype and issubclass(restype, Structure):
+			retval = restype()
+			objc_msgSend_stret = c['objc_msgSend_stret']
+			objc_msgSend_stret.argtypes = [c_void_p] + argtypes
+			objc_msgSend_stret.restype = None
+			objc_msgSend_stret(byref(retval), obj.ptr, sel(self.sel_name), *args)
+			return retval
+		else:
+			# NOTE: In order to be a little more thread-safe, we need a "private" handle for objc_msgSend(...).
+			# Otherwise, a different thread could modify argtypes/restype before the call is made...
+			objc_msgSend = self._objc_msgSend
+			if not objc_msgSend:
+				objc_msgSend = c['objc_msgSend']
+				objc_msgSend.argtypes = argtypes
+				objc_msgSend.restype = restype
+				# Cache the prepared function:
+				self._objc_msgSend = objc_msgSend
+
+			res = objc_msgSend(obj.ptr, sel(self.sel_name), *args)
+			return_type_enc = chr(type_encoding[0]) if PY3 else type_encoding[0]
+			if res and return_type_enc == '@':
+				# If an object is returned, wrap the pointer in an ObjCInstance:
+				if res == obj.ptr:
+					return obj
+				return ObjCInstance(res)
+			if restype == c_void_p and isinstance(res, int):
+				res = c_void_p(res)
+			return res
+
+#Some commonly-used Foundation/UIKit classes:
+NSObject = ObjCClass('NSObject')
+NSDictionary = ObjCClass('NSDictionary')
+NSMutableDictionary = ObjCClass('NSMutableDictionary')
+NSArray = ObjCClass('NSArray')
+NSMutableArray = ObjCClass('NSMutableArray')
+NSSet = ObjCClass('NSSet')
+NSMutableSet = ObjCClass('NSMutableSet')
+NSString = ObjCClass('NSString')
+NSMutableString = ObjCClass('NSMutableString')
+NSData = ObjCClass('NSData')
+NSMutableData = ObjCClass('NSMutableData')
+NSNumber = ObjCClass('NSNumber')
+NSURL = ObjCClass('NSURL')
+NSEnumerator = ObjCClass('NSEnumerator')
+NSThread = ObjCClass('NSThread')
+NSBundle = ObjCClass('NSBundle')
+
+UIColor = ObjCClass('UIColor')
+UIImage = ObjCClass('UIImage')
+UIBezierPath = ObjCClass('UIBezierPath')
+UIApplication = ObjCClass('UIApplication')
+UIView = ObjCClass('UIView')
+
+def load_framework(name):
+	return NSBundle.bundleWithPath_('/System/Library/Frameworks/%s.framework' % (name,)).load()
+
+# These are hard-coded for __dir__ (listing all NSObject methods dynamically would add tons of cruft from categories)
+# NOTE: This only includes *commonly-used* methods (a lot of this is pretty low-level runtime stuff that isn't needed
+#       very often. It can still be listed when calling dir() on an actual instance of NSObject)
+NSObject_class_methods = ['alloc', 'new', 'superclass', 'isSubclassOfClass_', 'instancesRespondToSelector_', 'description', 'cancelPreviousPerformRequestsWithTarget_', 'cancelPreviousPerformRequestsWithTarget_selector_object_']
+NSObject_instance_methods = ['init', 'copy', 'mutableCopy', 'dealloc', 'performSelector_withObject_afterDelay_', 'performSelectorOnMainThread_withObject_waitUntilDone_', 'performSelectorInBackground_withObject_']
+
+class _block_descriptor (Structure):
+	_fields_ = [('reserved', c_ulong), ('size', c_ulong), ('copy_helper', c_void_p), ('dispose_helper', c_void_p), ('signature', c_char_p)]
+
+class ObjCBlock (object):
+	def __init__(self, func, restype=None, argtypes=None):
+		if not callable(func):
+			raise TypeError('%s is not callable' % func)
+		if argtypes is None:
+			argtypes = []
+		InvokeFuncType = ctypes.CFUNCTYPE(restype, *argtypes)
+		class block_literal(Structure):
+			_fields_ = [('isa', c_void_p), ('flags', c_int), ('reserved', c_int), ('invoke', InvokeFuncType), ('descriptor', _block_descriptor)]
+		block = block_literal()
+		block.flags = (1<<28)
+		block.invoke = InvokeFuncType(func)
+		block.isa = ObjCClass('__NSGlobalBlock__').ptr
+		self.func = func
+		self._as_parameter_ = block if LP64 else byref(block)
+
+	@classmethod
+	def from_param(cls, param):
+		if isinstance(param, ObjCBlock) or param is None:
+			return param
+		elif callable(param):
+			block = ObjCBlock(param)
+			# Put a reference to the block into the function, so it doesn't get deallocated prematurely...
+			param._block = block
+			return block
+		raise TypeError('cannot convert parameter to block')
+
+	def __call__(self, *args):
+		return self.func(*args)
+
+type_encodings['@?'] = ObjCBlock
+
+
+def ns(py_obj):
+	'''Convert common Python objects to their ObjC equivalents, i.e. str => NSString, int/float => NSNumber, list => NSMutableArray, dict => NSMutableDictionary, bytearray => NSData, set => NSMutableSet. Nested structures (list/dict/set) are supported. If an object is already an instance of ObjCInstance, it is left untouched.
+		'''
+	if isinstance(py_obj, ObjCInstance):
+		return py_obj
+	if isinstance(py_obj, c_void_p):
+		return ObjCInstance(py_obj)
+	if hasattr(py_obj, '_objc_ptr'):
+		return ObjCInstance(py_obj)
+
+	if PY3:
+		if isinstance(py_obj, str):
+			return NSString.stringWithUTF8String_(py_obj.encode('utf-8'))
+		if isinstance(py_obj, bytes):
+			return NSData.dataWithBytes_length_(py_obj, len(py_obj))
+	else:
+		if isinstance(py_obj, str):
+			return NSString.stringWithUTF8String_(py_obj)
+		if isinstance(py_obj, unicode):
+			return NSString.stringWithUTF8String_(py_obj.encode('utf-8'))
+		if isinstance(py_obj, bytearray):
+			return NSData.dataWithBytes_length_(str(py_obj), len(py_obj))
+	if isinstance(py_obj, int):
+		return NSNumber.numberWithInt_(py_obj)
+	if isinstance(py_obj, float):
+		return NSNumber.numberWithDouble_(py_obj)
+	if isinstance(py_obj, bool):
+		return NSNumber.numberWithBool_(py_obj)
+	if isinstance(py_obj, list):
+		arr = NSMutableArray.array()
+		for obj in py_obj:
+			arr.addObject_(ns(obj))
+		return arr
+	if isinstance(py_obj, set):
+		s = NSMutableSet.set()
+		for obj in py_obj:
+			s.addObject_(ns(obj))
+		return s
+	if isinstance(py_obj, dict):
+		dct = NSMutableDictionary.dictionary()
+		for key, value in (py_obj.items() if PY3 else py_obj.iteritems()):
+			dct.setObject_forKey_(ns(value), ns(key))
+		return dct
+
+def nsurl(url_or_path):
+	if not isinstance(url_or_path, basestring):
+		raise TypeError('expected a string')
+	if ':' in url_or_path:
+		return NSURL.URLWithString_(ns(url_or_path))
+	return NSURL.fileURLWithPath_(ns(url_or_path))
+
+def nsdata_to_bytes(data):
+	if not isinstance(data, ObjCInstance) or not data.isKindOfClass_(NSData):
+		raise TypeError('expected an NSData object')
+	_len = data.length()
+	if _len == 0:
+		return b''
+	ArrayType = ctypes.c_char * _len
+	buffer = ArrayType()
+	data.getBytes_length_(byref(buffer), _len)
+	return buffer[:_len]
+
+def uiimage_to_png(img):
+	if not isinstance(img, ObjCInstance) or not img.isKindOfClass_(UIImage):
+		raise TypeError('expected a UIImage object')
+	UIImagePNGRepresentation = c.UIImagePNGRepresentation
+	UIImagePNGRepresentation.restype = c_void_p
+	UIImagePNGRepresentation.argtypes = [c_void_p]
+	data = ObjCInstance(UIImagePNGRepresentation(img))
+	return nsdata_to_bytes(data)
+
+def retain_global(obj):
+	'''Keep an object alive'''
+	_retained_globals.append(obj)
+
+def release_global(obj):
+	try:
+		_retained_globals.remove(obj)
+	except ValueError:
+		pass
+
+def OMMainThreadDispatcher_invoke_imp(self, cmd):
+	if _tracefunc:
+		sys.settrace(_tracefunc)
+	self_instance = ObjCInstance(self)
+	func = self_instance.func
+	args = self_instance.args
+	kwargs = self_instance.kwargs
+	retval = func(*args, **kwargs)
+	self_instance.retval = retval
+
+
+OMMainThreadDispatcher_name = b'OMMainThreadDispatcher_3' if PY3 else 'OMMainThreadDispatcher'
+try:
+	OMMainThreadDispatcher = ObjCClass(OMMainThreadDispatcher_name)
+except ValueError:
+	IMPTYPE = ctypes.CFUNCTYPE(None, c_void_p, c_void_p)
+	imp = IMPTYPE(OMMainThreadDispatcher_invoke_imp)
+	retain_global(imp)
+	NSObject = ObjCClass('NSObject')
+	class_ptr = objc_allocateClassPair(NSObject.ptr, OMMainThreadDispatcher_name, 0)
+	class_addMethod(class_ptr, sel('invoke'), imp, b'v16@0:0')
+	objc_registerClassPair(class_ptr)
+	OMMainThreadDispatcher = ObjCClass(OMMainThreadDispatcher_name)
+
+def on_main_thread(func):
+	if not callable(func):
+		raise TypeError('expected a callable')
+	@functools.wraps(func)
+	def new_func(*args, **kwargs):
+		if NSThread.isMainThread(restype=c_bool, argtypes=[]):
+			return func(*args, **kwargs)
+		dispatcher = OMMainThreadDispatcher.new()
+		dispatcher.func = func
+		dispatcher.args = args
+		dispatcher.kwargs = kwargs
+		dispatcher.retval = None
+		dispatcher.performSelectorOnMainThread_withObject_waitUntilDone_(sel('invoke'), None, True)
+		retval = dispatcher.retval
+		dispatcher.release()
+		return retval
+	return new_func
+
+def _add_method(method, class_ptr, superclass, basename, protocols, is_classmethod=False):
+	'''Helper function for create_objc_class, don't use directly (will usually crash)!'''
+	if hasattr(method, 'selector'):
+		sel_name = method.selector
+	else:
+		method_name = method.__name__
+		if method_name.startswith(basename + '_'):
+			method_name = method_name[len(basename)+1:]
+		sel_name = method_name.replace('_', ':')
+	type_encoding = None
+	if hasattr(method, 'encoding'):
+		# Explicit encoding was provided, trust that unconditionally...
+		type_encoding = method.encoding
+	else:
+		# No explicit encoding given, we have to guess...
+		# First, try to derive it from overridden methods in the superclass(es)...
+		if is_classmethod:
+			superclass_method = class_getClassMethod(superclass, sel(sel_name))
+		else:
+			superclass_method = class_getInstanceMethod(superclass, sel(sel_name))
+		if superclass_method:
+			type_encoding = method_getTypeEncoding(superclass_method)
+		else:
+			# Try to find a matching method in one of the protocols
+			for protocol_name in protocols:
+				if PY3 and isinstance(protocol_name, str):
+					protocol_name = protocol_name.encode('ascii')
+				protocol = objc_getProtocol(protocol_name)
+				if protocol:
+					# Try optional method first...
+					method_desc = protocol_getMethodDescription(protocol, sel(sel_name), False, True)
+					if not method_desc or not method_desc.types:
+						#... then required method
+						method_desc = protocol_getMethodDescription(protocol, sel(sel_name), True, True)
+					if method_desc and method_desc.types:
+						type_encoding = method_desc.types
+						break
+		if not type_encoding:
+			# Fall back to "action" type encoding as the default, i.e. void return type, all arguments are objects...
+			num_args = len(re.findall(':', sel_name))
+			type_encoding = 'v%i@0:8%s' % (sizeof(c_void_p) * (num_args + 2), ''.join('@%i' % ((i+2) * sizeof(c_void_p),) for i in xrange(num_args)))
+
+	if hasattr(method, 'restype') and hasattr(method, 'argtypes'):
+		restype = method.restype
+		argtypes = [c_void_p, c_void_p] + method.argtypes
+	else:
+		parsed_types = parse_types(type_encoding)
+		restype = parsed_types[0]
+		argtypes = parsed_types[1]
+	# Check if the number of arguments derived from the selector matches the actual function:
+	argspec = inspect.getargspec(method)
+	if len(argspec.args) != len(argtypes):
+		raise ValueError('%s has %i arguments (expected %i)' % (method, len(argspec.args), len(argtypes)))
+	IMPTYPE = ctypes.CFUNCTYPE(restype, *argtypes)
+	imp = IMPTYPE(method)
+	retain_global(imp)
+	if PY3 and isinstance(type_encoding, str):
+		type_encoding = type_encoding.encode('ascii')
+	class_addMethod(class_ptr, sel(sel_name), imp, type_encoding)
+
+def create_objc_class(name, superclass=NSObject, methods=[], classmethods=[], protocols=[], debug=True):
+	'''Create and return a new Objective-C class'''
+	basename = name
+	if debug:
+		# When debug is True (the default) and a class with the given name already exists in the runtime,
+		# append an incrementing numeric suffix, until a class name is found that doesn't exist yet.
+		# While this does leak some memory, it makes development much easier. Note however that the returned
+		# class may not have the name you passed in (use the return value directly instead of relying on the name)
+		suffix = 1
+		while True:
+			try:
+				existing_class = ObjCClass(name)
+				suffix += 1
+				name = '%s_%i' % (basename, suffix)
+			except ValueError:
+				break
+	else:
+		# When debug is False, assume that any class is created only once, and return an existing class
+		# with the given name. Note that this ignores all other parameters. This is intended to avoid
+		# unnecessary memory leaks when the class definition doesn't change anymore.
+		try:
+			existing_class = ObjCClass(basename)
+			return existing_class
+		except ValueError:
+			pass
+	if PY3 and isinstance(name, str):
+		name = name.encode('ascii')	
+	class_ptr = objc_allocateClassPair(superclass, name, 0)
+
+	for method in methods:
+		_add_method(method, class_ptr, superclass, basename, protocols)
+
+	objc_registerClassPair(class_ptr)
+
+	for method in classmethods:
+		metaclass = object_getClass(class_ptr)
+		super_metaclass = object_getClass(class_getSuperclass(class_ptr))
+		_add_method(method, metaclass, super_metaclass, basename, [], True)
+	return ObjCClass(name)
+
+def settrace(func):
+	# used for on_main_thread()
+	global _tracefunc
+	_tracefunc = func