OLD | NEW |
(Empty) | |
| 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 #import "base/mac/scoped_objc_class_swizzler.h" |
| 6 |
| 7 #include <string.h> |
| 8 |
| 9 #include "base/logging.h" |
| 10 |
| 11 namespace base { |
| 12 namespace mac { |
| 13 |
| 14 ScopedObjCClassSwizzler::ScopedObjCClassSwizzler(Class target, |
| 15 Class source, |
| 16 SEL selector) |
| 17 : old_selector_impl_(NULL), new_selector_impl_(NULL) { |
| 18 Init(target, source, selector, selector); |
| 19 } |
| 20 |
| 21 ScopedObjCClassSwizzler::ScopedObjCClassSwizzler(Class target, |
| 22 SEL original, |
| 23 SEL alternate) |
| 24 : old_selector_impl_(NULL), new_selector_impl_(NULL) { |
| 25 Init(target, target, original, alternate); |
| 26 } |
| 27 |
| 28 ScopedObjCClassSwizzler::~ScopedObjCClassSwizzler() { |
| 29 if (old_selector_impl_ && new_selector_impl_) |
| 30 method_exchangeImplementations(old_selector_impl_, new_selector_impl_); |
| 31 } |
| 32 |
| 33 IMP ScopedObjCClassSwizzler::GetOriginalImplementation() { |
| 34 // Note that while the swizzle is in effect the "new" method is actually |
| 35 // pointing to the original implementation, since they have been swapped. |
| 36 return method_getImplementation(new_selector_impl_); |
| 37 } |
| 38 |
| 39 void ScopedObjCClassSwizzler::Init(Class target, |
| 40 Class source, |
| 41 SEL original, |
| 42 SEL alternate) { |
| 43 old_selector_impl_ = class_getInstanceMethod(target, original); |
| 44 new_selector_impl_ = class_getInstanceMethod(source, alternate); |
| 45 if (!old_selector_impl_ && !new_selector_impl_) { |
| 46 // Try class methods. |
| 47 old_selector_impl_ = class_getClassMethod(target, original); |
| 48 new_selector_impl_ = class_getClassMethod(source, alternate); |
| 49 } |
| 50 |
| 51 DCHECK(old_selector_impl_); |
| 52 DCHECK(new_selector_impl_); |
| 53 if (!old_selector_impl_ || !new_selector_impl_) |
| 54 return; |
| 55 |
| 56 // The argument and return types must match exactly. |
| 57 const char* old_types = method_getTypeEncoding(old_selector_impl_); |
| 58 const char* new_types = method_getTypeEncoding(new_selector_impl_); |
| 59 DCHECK(old_types); |
| 60 DCHECK(new_types); |
| 61 DCHECK_EQ(0, strcmp(old_types, new_types)); |
| 62 if (!old_types || !new_types || strcmp(old_types, new_types)) { |
| 63 old_selector_impl_ = new_selector_impl_ = NULL; |
| 64 return; |
| 65 } |
| 66 |
| 67 method_exchangeImplementations(old_selector_impl_, new_selector_impl_); |
| 68 } |
| 69 |
| 70 } // namespace mac |
| 71 } // namespace base |
OLD | NEW |