skia2/include/utils/win/SkTScopedComPtr.h
2012-08-16 16:13:40 +00:00

65 lines
1.5 KiB
C++

/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkSkTScopedPtr_DEFINED
#define SkSkTScopedPtr_DEFINED
#include "SkTypes.h"
#include "SkTemplates.h"
template<typename T>
class SkBlockComRef : public T {
private:
virtual ULONG STDMETHODCALLTYPE AddRef(void) = 0;
virtual ULONG STDMETHODCALLTYPE Release(void) = 0;
};
template<typename T>
class SkTScopedComPtr : SkNoncopyable {
private:
T *fPtr;
public:
explicit SkTScopedComPtr(T *ptr = NULL) : fPtr(ptr) { }
~SkTScopedComPtr() {
this->reset();
}
T &operator*() const { SkASSERT(fPtr != NULL); return *fPtr; }
SkBlockComRef<T> *operator->() const {
return static_cast<SkBlockComRef<T>*>(fPtr);
}
/**
* Returns the address of the underlying pointer.
* This is dangerous -- it breaks encapsulation and the reference escapes.
* Must only be used on instances currently pointing to NULL,
* and only to initialize the instance.
*/
T **operator&() { SkASSERT(fPtr == NULL); return &fPtr; }
T *get() const { return fPtr; }
void reset() {
if (NULL != this->fPtr) {
this->fPtr->Release();
this->fPtr = NULL;
}
}
void swap(SkTScopedComPtr<T>& that) {
T* temp = this->fPtr;
this->fPtr = that.fPtr;
that.fPtr = temp;
}
T* release() {
T* temp = this->fPtr;
this->fPtr = NULL;
return temp;
}
};
#endif