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/*
* Copyright (C) 2011 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef SkTScopedPtr_DEFINED
#define SkTScopedPtr_DEFINED
#include "SkTypes.h"
/** \class SkTScopedPtr
A SkTScopedPtr<T> is like a T*, except that the destructor of SkTScopedPtr<T>
automatically deletes the pointer it holds (if any). That is, SkTScopedPtr<T>
owns the T object that it points to. Like a T*, a SkTScopedPtr<T> may hold
either NULL or a pointer to a T object. Also like T*, SkTScopedPtr<T> is
thread-compatible, and once you dereference it, you get the threadsafety
guarantees of T.
The size of a SkTScopedPtr is small: sizeof(SkTScopedPtr<T>) == sizeof(T*)
*/
template <typename T> class SkTScopedPtr : SkNoncopyable {
public:
explicit SkTScopedPtr(T* o = NULL) : fObj(o) {}
~SkTScopedPtr() {
enum { kTypeMustBeComplete = sizeof(T) };
delete fObj;
}
/** Delete the current object, if any. Then take ownership of the
passed object.
*/
void reset(T* o = NULL) {
if (o != fObj) {
enum { kTypeMustBeComplete = sizeof(T) };
delete fObj;
fObj = o;
}
}
/** Without deleting the current object, return it and forget about it.
Similar to calling get() and reset(), but the object is not deleted.
*/
T* release() {
T* retVal = fObj;
fObj = NULL;
return retVal;
}
T& operator*() const {
SkASSERT(fObj != NULL);
return *fObj;
}
T* operator->() const {
SkASSERT(fObj != NULL);
return fObj;
}
T* get() const { return fObj; }
bool operator==(T* o) const { return fObj == o; }
bool operator!=(T* o) const { return fObj != o; }
private:
T* fObj;
// Forbid comparison of SkTScopedPtr types. If T2 != T, it doesn't make
// sense, and if T2 == T, it still doesn't make sense because the same
// object can't be owned by two different scoped_ptrs.
template <class T2> bool operator==(SkTScopedPtr<T2> const& o2) const;
template <class T2> bool operator!=(SkTScopedPtr<T2> const& o2) const;
};
#endif
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