base/mac/scoped_objc_class_swizzler.h

   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
  13 namespace base {
  14 namespace 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.
  18 class 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_