1 2 /* 3 * Copyright 2011 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #ifndef SkTScopedPtr_DEFINED 11 #define SkTScopedPtr_DEFINED 12 13 #include "SkTypes.h" 14 15 /** \class SkTScopedPtr 16 A SkTScopedPtr<T> is like a T*, except that the destructor of SkTScopedPtr<T> 17 automatically deletes the pointer it holds (if any). That is, SkTScopedPtr<T> 18 owns the T object that it points to. Like a T*, a SkTScopedPtr<T> may hold 19 either NULL or a pointer to a T object. Also like T*, SkTScopedPtr<T> is 20 thread-compatible, and once you dereference it, you get the threadsafety 21 guarantees of T. 22 23 The size of a SkTScopedPtr is small: sizeof(SkTScopedPtr<T>) == sizeof(T*) 24 */ 25 template <typename T> class SkTScopedPtr : SkNoncopyable { 26 public: fObj(o)27 explicit SkTScopedPtr(T* o = NULL) : fObj(o) {} ~SkTScopedPtr()28 ~SkTScopedPtr() { 29 enum { kTypeMustBeComplete = sizeof(T) }; 30 delete fObj; 31 } 32 33 /** Delete the current object, if any. Then take ownership of the 34 passed object. 35 */ 36 void reset(T* o = NULL) { 37 if (o != fObj) { 38 enum { kTypeMustBeComplete = sizeof(T) }; 39 delete fObj; 40 fObj = o; 41 } 42 } 43 44 /** Without deleting the current object, return it and forget about it. 45 Similar to calling get() and reset(), but the object is not deleted. 46 */ release()47 T* release() { 48 T* retVal = fObj; 49 fObj = NULL; 50 return retVal; 51 } 52 53 T& operator*() const { 54 SkASSERT(fObj != NULL); 55 return *fObj; 56 } 57 T* operator->() const { 58 SkASSERT(fObj != NULL); 59 return fObj; 60 } get()61 T* get() const { return fObj; } 62 63 bool operator==(T* o) const { return fObj == o; } 64 bool operator!=(T* o) const { return fObj != o; } 65 66 private: 67 T* fObj; 68 69 // Forbid comparison of SkTScopedPtr types. If T2 != T, it doesn't make 70 // sense, and if T2 == T, it still doesn't make sense because the same 71 // object can't be owned by two different scoped_ptrs. 72 template <class T2> bool operator==(SkTScopedPtr<T2> const& o2) const; 73 template <class T2> bool operator!=(SkTScopedPtr<T2> const& o2) const; 74 }; 75 76 #endif 77