1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_MAC_SCOPED_OBJC_CLASS_SWIZZLER_H_
6#define BASE_MAC_SCOPED_OBJC_CLASS_SWIZZLER_H_
7
8#import <objc/runtime.h>
9
10#include "base/base_export.h"
11#include "base/macros.h"
12
13namespace base {
14namespace mac {
15
16// Within a given scope, swaps method implementations of a class interface, or
17// between two class interfaces. The argument and return types must match.
18class BASE_EXPORT ScopedObjCClassSwizzler {
19 public:
20  // Given two classes that each respond to |selector|, swap the implementations
21  // of those methods.
22  ScopedObjCClassSwizzler(Class target, Class source, SEL selector);
23
24  // Given two selectors on the same class interface, |target| (e.g. via
25  // inheritance or categories), swap the implementations of methods |original|
26  // and |alternate|.
27  ScopedObjCClassSwizzler(Class target, SEL original, SEL alternate);
28
29  ~ScopedObjCClassSwizzler();
30
31  // Return a callable function pointer for the replaced method. To call this
32  // from the replacing function, the first two arguments should be |self| and
33  // |_cmd|. These are followed by the (variadic) method arguments.
34  IMP GetOriginalImplementation();
35
36 private:
37  // Delegated constructor.
38  void Init(Class target, Class source, SEL original, SEL alternate);
39
40  Method old_selector_impl_;
41  Method new_selector_impl_;
42
43  DISALLOW_COPY_AND_ASSIGN(ScopedObjCClassSwizzler);
44};
45
46}  // namespace mac
47}  // namespace base
48
49#endif  // BASE_MAC_SCOPED_OBJC_CLASS_SWIZZLER_H_
50