58 lines
2.1 KiB
Objective-C
58 lines
2.1 KiB
Objective-C
// Copyright 2014 The Chromium Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_MAC_SCOPED_OBJC_CLASS_SWIZZLER_H_
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#define BASE_MAC_SCOPED_OBJC_CLASS_SWIZZLER_H_
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#import <objc/runtime.h>
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#include "base/base_export.h"
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namespace base::mac {
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// Within a given scope, swaps method implementations of a class interface, or
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// between two class interfaces. The argument and return types must match.
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class BASE_EXPORT ScopedObjCClassSwizzler {
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public:
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// Given two classes that each respond to |selector|, swap the implementations
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// of those methods.
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ScopedObjCClassSwizzler(Class target, Class source, SEL selector);
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// Given two selectors on the same class interface, |target| (e.g. via
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// inheritance or categories), swap the implementations of methods |original|
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// and |alternate|.
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ScopedObjCClassSwizzler(Class target, SEL original, SEL alternate);
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ScopedObjCClassSwizzler(const ScopedObjCClassSwizzler&) = delete;
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ScopedObjCClassSwizzler& operator=(const ScopedObjCClassSwizzler&) = delete;
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~ScopedObjCClassSwizzler();
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// Return a callable function pointer for the replaced method. To call this
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// from the replacing function, the first two arguments should be |self| and
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// |_cmd|. These are followed by the (variadic) method arguments.
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IMP GetOriginalImplementation() const;
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// Invoke the original function directly, optionally with some arguments.
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// Prefer this to hanging onto pointers to the original implementation
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// function or to casting the result of GetOriginalImplementation() yourself.
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template <typename Ret, typename... Args>
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Ret InvokeOriginal(id receiver, SEL selector, Args... args) const {
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auto func = reinterpret_cast<Ret (*)(id, SEL, Args...)>(
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GetOriginalImplementation());
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return func(receiver, selector, args...);
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}
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private:
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// Delegated constructor.
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void Init(Class target, Class source, SEL original, SEL alternate);
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Method old_selector_impl_;
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Method new_selector_impl_;
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};
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} // namespace base::mac
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#endif // BASE_MAC_SCOPED_OBJC_CLASS_SWIZZLER_H_
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