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/*
* libjingle
* Copyright 2011, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// Originally these classes are from Chromium.
// http://src.chromium.org/viewvc/chrome/trunk/src/base/memory/ref_counted.h?view=markup
//
// A smart pointer class for reference counted objects. Use this class instead
// of calling AddRef and Release manually on a reference counted object to
// avoid common memory leaks caused by forgetting to Release an object
// reference. Sample usage:
//
// class MyFoo : public RefCounted<MyFoo> {
// ...
// };
//
// void some_function() {
// scoped_refptr<MyFoo> foo = new MyFoo();
// foo->Method(param);
// // |foo| is released when this function returns
// }
//
// void some_other_function() {
// scoped_refptr<MyFoo> foo = new MyFoo();
// ...
// foo = NULL; // explicitly releases |foo|
// ...
// if (foo)
// foo->Method(param);
// }
//
// The above examples show how scoped_refptr<T> acts like a pointer to T.
// Given two scoped_refptr<T> classes, it is also possible to exchange
// references between the two objects, like so:
//
// {
// scoped_refptr<MyFoo> a = new MyFoo();
// scoped_refptr<MyFoo> b;
//
// b.swap(a);
// // now, |b| references the MyFoo object, and |a| references NULL.
// }
//
// To make both |a| and |b| in the above example reference the same MyFoo
// object, simply use the assignment operator:
//
// {
// scoped_refptr<MyFoo> a = new MyFoo();
// scoped_refptr<MyFoo> b;
//
// b = a;
// // now, |a| and |b| each own a reference to the same MyFoo object.
// }
//
#ifndef TALK_BASE_SCOPED_REF_PTR_H_
#define TALK_BASE_SCOPED_REF_PTR_H_
#include <stddef.h>
namespace talk_base {
template <class T>
class scoped_refptr {
public:
scoped_refptr() : ptr_(NULL) {
}
scoped_refptr(T* p) : ptr_(p) {
if (ptr_)
ptr_->AddRef();
}
scoped_refptr(const scoped_refptr<T>& r) : ptr_(r.ptr_) {
if (ptr_)
ptr_->AddRef();
}
template <typename U>
scoped_refptr(const scoped_refptr<U>& r) : ptr_(r.get()) {
if (ptr_)
ptr_->AddRef();
}
~scoped_refptr() {
if (ptr_)
ptr_->Release();
}
T* get() const { return ptr_; }
operator T*() const { return ptr_; }
T* operator->() const { return ptr_; }
// Release a pointer.
// The return value is the current pointer held by this object.
// If this object holds a NULL pointer, the return value is NULL.
// After this operation, this object will hold a NULL pointer,
// and will not own the object any more.
T* release() {
T* retVal = ptr_;
ptr_ = NULL;
return retVal;
}
scoped_refptr<T>& operator=(T* p) {
// AddRef first so that self assignment should work
if (p)
p->AddRef();
if (ptr_ )
ptr_ ->Release();
ptr_ = p;
return *this;
}
scoped_refptr<T>& operator=(const scoped_refptr<T>& r) {
return *this = r.ptr_;
}
template <typename U>
scoped_refptr<T>& operator=(const scoped_refptr<U>& r) {
return *this = r.get();
}
void swap(T** pp) {
T* p = ptr_;
ptr_ = *pp;
*pp = p;
}
void swap(scoped_refptr<T>& r) {
swap(&r.ptr_);
}
protected:
T* ptr_;
};
} // namespace talk_base
#endif // TALK_BASE_SCOPED_REF_PTR_H_
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