1 // Copyright 2013 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 LIBRARIES_SDK_UTIL_SCOPED_REF_H_ 6 #define LIBRARIES_SDK_UTIL_SCOPED_REF_H_ 7 8 #include <stdlib.h> 9 10 #include "sdk_util/macros.h" 11 #include "sdk_util/ref_object.h" 12 13 namespace sdk_util { 14 15 class ScopedRefBase { 16 protected: ScopedRefBase()17 ScopedRefBase() : ptr_(NULL) {} ~ScopedRefBase()18 ~ScopedRefBase() { reset(NULL); } 19 reset(RefObject * obj)20 void reset(RefObject* obj) { 21 if (obj) { 22 obj->Acquire(); 23 } 24 if (ptr_) { 25 ptr_->Release(); 26 } 27 ptr_ = obj; 28 } 29 30 protected: 31 RefObject* ptr_; 32 }; 33 34 template <class T> 35 class ScopedRef : public ScopedRefBase { 36 public: ScopedRef()37 ScopedRef() {} ScopedRef(const ScopedRef & ptr)38 ScopedRef(const ScopedRef& ptr) { reset(ptr.get()); } ScopedRef(T * ptr)39 explicit ScopedRef(T* ptr) { reset(ptr); } 40 41 ScopedRef& operator=(const ScopedRef& ptr) { 42 reset(ptr.get()); 43 return *this; 44 } 45 46 template <typename U> ScopedRef(const ScopedRef<U> & ptr)47 ScopedRef(const ScopedRef<U>& ptr) { 48 reset(ptr.get()); 49 } 50 51 template <typename U> 52 ScopedRef& operator=(const ScopedRef<U>& ptr) { 53 reset(ptr.get()); 54 return *this; 55 } 56 57 void reset(T* obj = NULL) { ScopedRefBase::reset(obj); } get()58 T* get() const { return static_cast<T*>(ptr_); } 59 60 template <typename U> 61 bool operator==(const ScopedRef<U>& p) const { 62 return get() == p.get(); 63 } 64 65 template <typename U> 66 bool operator!=(const ScopedRef<U>& p) const { 67 return get() != p.get(); 68 } 69 70 public: 71 T& operator*() const { return *get(); } 72 T* operator->() const { return get(); } 73 74 private: 75 typedef void (ScopedRef::*bool_as_func_ptr)() const; bool_as_func_impl()76 void bool_as_func_impl() const {}; 77 78 public: bool_as_func_ptr()79 operator bool_as_func_ptr() const { 80 return (ptr_ != NULL) ? &ScopedRef::bool_as_func_impl : 0; 81 } 82 }; 83 84 template <typename U, typename T> static_scoped_ref_cast(const ScopedRef<T> & ptr)85ScopedRef<U> static_scoped_ref_cast(const ScopedRef<T>& ptr) { 86 return ScopedRef<U>(static_cast<U*>(ptr.get())); 87 } 88 89 } // namespace sdk_util 90 91 #endif // LIBRARIES_SDK_UTIL_SCOPED_REF_H_ 92