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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <cstring>
#include <vector>
namespace mongo {
/**
* An std::vector wrapper that deletes pointers within a vector on destruction. The objects
* referenced by the vector's pointers are 'owned' by an object of this class.
* NOTE that an OwnedPointerVector<T> wraps an std::vector<T*>.
*/
template <class T>
class OwnedPointerVector {
OwnedPointerVector(const OwnedPointerVector&) = delete;
OwnedPointerVector& operator=(const OwnedPointerVector&) = delete;
public:
OwnedPointerVector() {}
~OwnedPointerVector() {
clear();
}
/**
* Takes ownership of all pointers contained in 'other'.
* NOTE: argument is intentionally taken by value.
*/
OwnedPointerVector(std::vector<T*> other) {
_vector.swap(other);
}
/**
* Takes ownership of all pointers contained in 'other'.
* NOTE: argument is intentionally taken by value.
*/
OwnedPointerVector& operator=(std::vector<T*> other) {
clear();
_vector.swap(other);
return *this;
}
typedef typename std::vector<T*>::const_iterator const_iterator;
typedef typename std::vector<T*>::const_reverse_iterator const_reverse_iterator;
/** Access the vector. */
const std::vector<T*>& vector() const {
return _vector;
}
std::vector<T*>& mutableVector() {
return _vector;
}
std::size_t size() const {
return _vector.size();
}
bool empty() const {
return _vector.empty();
}
const_iterator begin() const {
return _vector.begin();
}
const_reverse_iterator rbegin() const {
return _vector.rbegin();
}
const_iterator end() const {
return _vector.end();
}
const_reverse_iterator rend() const {
return _vector.rend();
}
T* operator[](size_t i) const {
return _vector[i];
}
T* back() const {
return _vector.back();
}
T* front() const {
return _vector.front();
}
void push_back(T* ptr) {
_vector.push_back(ptr);
}
/**
* Deletes all pointers in the vector, then sets its size to 0.
*/
void clear();
/**
* Deletes the pointer at 'it', then erases it from the vector.
*/
void erase(const_iterator it) {
delete *it;
_vector.erase(toNonConstIter(it));
}
void erase(const_iterator begin, const_iterator end) {
for (const_iterator it = begin; it != end; ++it) {
delete *it;
}
_vector.erase(toNonConstIter(begin), toNonConstIter(end));
}
//
// extensions
//
/**
* Releases the entire vector to allow you to transfer ownership.
*
* Leaves the OwnedPointerVector empty.
* Named after the similar method and pattern in std::unique_ptr.
*/
std::vector<T*> release() {
std::vector<T*> out;
out.swap(_vector);
return out;
}
/**
* Releases ownership of a single element.
*
* Sets that element to NULL and does not change size().
*/
T* releaseAt(size_t i) {
T* out = _vector[i];
_vector[i] = nullptr;
return out;
}
T* popAndReleaseBack() {
T* out = _vector.back();
_vector.pop_back();
return out;
}
void popAndDeleteBack() {
delete popAndReleaseBack();
}
private:
typename std::vector<T*>::iterator toNonConstIter(const_iterator it) {
// This is needed for a few cases where c++03 vectors require non-const iterators that
// were relaxed in c++11 to allow const_iterators. It can go away when we require c++11.
return _vector.begin() + (it - begin());
}
std::vector<T*> _vector;
};
template <class T>
inline void OwnedPointerVector<T>::clear() {
for (typename std::vector<T*>::iterator i = _vector.begin(); i != _vector.end(); ++i) {
delete *i;
}
_vector.clear();
}
} // namespace mongo
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