Fix compilation issues with CFRetain and CFAutorelease

Author: akshayaurora

pyobjus/pyobjus.pyx

@@ -878,6 +878,9 @@ cdef void protocol_forwardInvocation(id self, SEL _cmd, id invocation) with gil:
     cls_name = class_getName(cls)
     for i in range(2, signature.numberOfArguments):
         tp = signature.getArgumentTypeAtIndex_(i)
+        if isinstance(tp, unicode):
+            tp = tp.encode('utf8')
+        tp = clean_type_specifier(tp)
         dprint("pfi: argument type at {}: {}".format(i, tp))
         arg_type = type_encoding_to_ffitype(tp[:1])
         dprint('pfi: convert arg {} with type {}'.format(i, tp[:1]))
@@ -898,16 +901,15 @@ cdef void protocol_forwardInvocation(id self, SEL _cmd, id invocation) with gil:
         py_method = getattr(delegate, py_method_name)
         py_ret = py_method(*py_method_args)
 
-    # Return type from the @protocol encoding (first char). Prefer the live
-    # NSInvocation signature so setReturnValue: size always matches what
-    # methodSignatureForSelector: advertised (including after a cache refresh
-    # when runtime CGFloat encodings replace a stale float fallback).
+    # Return type from the live NSInvocation signature (preferred) or the
+    # @protocol encoding. Strip ObjC type qualifiers (r/n/N/o/O/R/V) before
+    # selecting the kind, consistent with clean_type_specifier elsewhere.
     kind = b'v'
     ret_tp = signature.methodReturnType
     if ret_tp is not None:
-        kind = ret_tp[:1]
-        if isinstance(kind, unicode):
-            kind = kind.encode('utf8')
+        if isinstance(ret_tp, unicode):
+            ret_tp = ret_tp.encode('utf8')
+        kind = clean_type_specifier(ret_tp)[:1]
     elif py_method is not None and hasattr(py_method, '__protocol__'):
         sel_name = sel_getName(_cmd).decode('utf8')
         d = objc_protocol_get_delegates(py_method.__protocol__)
@@ -916,13 +918,16 @@ cdef void protocol_forwardInvocation(id self, SEL _cmd, id invocation) with gil:
             enc = sigs[-1]
             if isinstance(enc, unicode):
                 enc = enc.encode('utf8')
-            kind = enc[:1]
+            kind = clean_type_specifier(enc)[:1]
     if kind == b'v':
         return
     if kind == b'@':
         obj = convert_py_to_nsobject(py_ret) if py_ret is not None else None
         ret_id = (<ObjcClassInstance>obj).o_instance if obj is not None else <id>NULL
         if ret_id != NULL:
+            # Keep the returned object alive across the NSInvocation handoff.
+            # CoreFoundation is linked on macOS by default; on iOS setup.py
+            # adds -framework CoreFoundation.
             CFRetain(<void*>ret_id)
             CFAutorelease(<void*>ret_id)
         inv.setReturnValue_(<unsigned long long>&ret_id)

setup.py

@@ -61,6 +61,8 @@ def build_extensions(self):
     include_dirs.append(join(ffi_lib_path, "include"))
     include_dirs.append(join(ffi_lib_path, "include", "ffi"))
     libraries.append('objc')
+    # protocol_forwardInvocation uses CFRetain/CFAutorelease for object returns.
+    extra_link_args.extend(['-framework', 'CoreFoundation'])
 
 depends = [join('pyobjus', x) for x in (
     'common.pxi',

tests/test_delegate_returns.py

@@ -36,6 +36,12 @@ def nameForKey_(self, key):
         self.log.append('name')
         return objc_str('icon.png')
 
+    @protocol('PyobjusReturnTest')
+    def constNameForKey_(self, key):
+        # Encoding uses leading 'r' (const) qualifier — must still forward @.
+        self.log.append('const-name')
+        return objc_str('icon.png')
+
     @protocol('PyobjusReturnTest')
     def flagForKey_(self, key):
         self.log.append('flag')
@@ -69,6 +75,7 @@ def setUpClass(cls):
         load_framework(INCLUDE.AppKit)
         protocols['PyobjusReturnTest'] = {
             'nameForKey:': ('@@:@', '@@:@'),
+            'constNameForKey:': ('r@@:@', 'r@@:@'),
             'flagForKey:': ('B@:@', 'B@:@'),
             'countForKey:': ('Q@:@', 'Q@:@'),
             'floatForKey:': ('f@:@', 'f@:@'),
@@ -91,6 +98,15 @@ def test_msgsend_string_return(self):
         length = _msg_send(ctypes.c_ulong, ptr, 'length')
         self.assertEqual(length, len('icon.png'))
 
+    def test_msgsend_const_qualified_string_return(self):
+        ptr = _msg_send(
+            ctypes.c_void_p, self.target, 'constNameForKey:', self.key)
+        self.assertIn('const-name', self.delegate.log)
+        self.assertTrue(
+            ptr, 'const-qualified NSString return was NULL (qualifier strip?)')
+        length = _msg_send(ctypes.c_ulong, ptr, 'length')
+        self.assertEqual(length, len('icon.png'))
+
     def test_msgsend_bool_return(self):
         val = _msg_send(
             ctypes.c_ubyte, self.target, 'flagForKey:', self.key)