blob: 8b12c07e5acc08a675d891bda2e9592d29c6ae7c [file] [log] [blame]
/*
* 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 SkTScopedComPtr_DEFINED
#define SkTScopedComPtr_DEFINED
#include "SkLeanWindows.h"
#ifdef SK_BUILD_FOR_WIN
template<typename T>
class SkBlockComRef : public T {
private:
virtual ULONG STDMETHODCALLTYPE AddRef(void) = 0;
virtual ULONG STDMETHODCALLTYPE Release(void) = 0;
virtual ~SkBlockComRef() {}
};
template<typename T> T* SkRefComPtr(T* ptr) {
ptr->AddRef();
return ptr;
}
template<typename T> T* SkSafeRefComPtr(T* ptr) {
if (ptr) {
ptr->AddRef();
}
return ptr;
}
template<typename T>
class SkTScopedComPtr {
private:
T *fPtr;
public:
constexpr SkTScopedComPtr() : fPtr(nullptr) {}
constexpr SkTScopedComPtr(std::nullptr_t) : fPtr(nullptr) {}
explicit SkTScopedComPtr(T *ptr) : fPtr(ptr) {}
SkTScopedComPtr(SkTScopedComPtr&& that) : fPtr(that.release()) {}
SkTScopedComPtr(const SkTScopedComPtr&) = delete;
~SkTScopedComPtr() { this->reset();}
SkTScopedComPtr& operator=(SkTScopedComPtr&& that) {
this->reset(that.release());
return *this;
}
SkTScopedComPtr& operator=(const SkTScopedComPtr&) = delete;
SkTScopedComPtr& operator=(std::nullptr_t) { this->reset(); return *this; }
T &operator*() const { SkASSERT(fPtr != nullptr); return *fPtr; }
explicit operator bool() const { return fPtr != nullptr; }
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 == nullptr); return &fPtr; }
T *get() const { return fPtr; }
void reset(T* ptr = nullptr) {
if (fPtr) {
fPtr->Release();
}
fPtr = ptr;
}
void swap(SkTScopedComPtr<T>& that) {
T* temp = this->fPtr;
this->fPtr = that.fPtr;
that.fPtr = temp;
}
T* release() {
T* temp = this->fPtr;
this->fPtr = nullptr;
return temp;
}
};
#endif // SK_BUILD_FOR_WIN
#endif // SkTScopedComPtr_DEFINED