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// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "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 COPYRIGHT
// OWNER OR CONTRIBUTORS 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.
#ifndef V8_SMART_POINTERS_H_
#define V8_SMART_POINTERS_H_
namespace v8 {
namespace internal {
template<typename Deallocator, typename T>
class SmartPointerBase {
public:
// Default constructor. Constructs an empty scoped pointer.
inline SmartPointerBase() : p_(NULL) {}
// Constructs a scoped pointer from a plain one.
explicit inline SmartPointerBase(T* ptr) : p_(ptr) {}
// Copy constructor removes the pointer from the original to avoid double
// freeing.
inline SmartPointerBase(const SmartPointerBase<Deallocator, T>& rhs)
: p_(rhs.p_) {
const_cast<SmartPointerBase<Deallocator, T>&>(rhs).p_ = NULL;
}
// When the destructor of the scoped pointer is executed the plain pointer
// is deleted using DeleteArray. This implies that you must allocate with
// NewArray.
inline ~SmartPointerBase() { if (p_) Deallocator::Delete(p_); }
inline T* operator->() const { return p_; }
// You can get the underlying pointer out with the * operator.
inline T* operator*() { return p_; }
// You can use [n] to index as if it was a plain pointer
inline T& operator[](size_t i) {
return p_[i];
}
// We don't have implicit conversion to a T* since that hinders migration:
// You would not be able to change a method from returning a T* to
// returning an SmartArrayPointer<T> and then get errors wherever it is used.
// If you want to take out the plain pointer and don't want it automatically
// deleted then call Detach(). Afterwards, the smart pointer is empty
// (NULL).
inline T* Detach() {
T* temp = p_;
p_ = NULL;
return temp;
}
// Assignment requires an empty (NULL) SmartArrayPointer as the receiver. Like
// the copy constructor it removes the pointer in the original to avoid
// double freeing.
inline SmartPointerBase<Deallocator, T>& operator=(
const SmartPointerBase<Deallocator, T>& rhs) {
ASSERT(is_empty());
T* tmp = rhs.p_; // swap to handle self-assignment
const_cast<SmartPointerBase<Deallocator, T>&>(rhs).p_ = NULL;
p_ = tmp;
return *this;
}
inline bool is_empty() { return p_ == NULL; }
private:
T* p_;
};
// A 'scoped array pointer' that calls DeleteArray on its pointer when the
// destructor is called.
template<typename T>
struct ArrayDeallocator {
static void Delete(T* array) {
DeleteArray(array);
}
};
template<typename T>
class SmartArrayPointer: public SmartPointerBase<ArrayDeallocator<T>, T> {
public:
inline SmartArrayPointer() { }
explicit inline SmartArrayPointer(T* ptr)
: SmartPointerBase<ArrayDeallocator<T>, T>(ptr) { }
inline SmartArrayPointer(const SmartArrayPointer<T>& rhs)
: SmartPointerBase<ArrayDeallocator<T>, T>(rhs) { }
};
template<typename T>
struct ObjectDeallocator {
static void Delete(T* array) {
Malloced::Delete(array);
}
};
template<typename T>
class SmartPointer: public SmartPointerBase<ObjectDeallocator<T>, T> {
public:
inline SmartPointer() { }
explicit inline SmartPointer(T* ptr)
: SmartPointerBase<ObjectDeallocator<T>, T>(ptr) { }
inline SmartPointer(const SmartPointer<T>& rhs)
: SmartPointerBase<ObjectDeallocator<T>, T>(rhs) { }
};
} } // namespace v8::internal
#endif // V8_SMART_POINTERS_H_
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