te_intrusive_ptr.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef TETRAEDGE_TE_TE_INTRUSIVE_PTR_H
#define TETRAEDGE_TE_TE_INTRUSIVE_PTR_H

namespace Tetraedge {

template<class T> class TeIntrusivePtr {
public:
    // NOTE: The original uses a member function for this, which is cleaner, but
    // MSVC compiles member functions for different class types (forward
    // declaration, multi-inheritance, etc) as differnt sizes which causes all
    // sorts of issues.  Only accept a static function to avoid such problems.
    typedef void(*Tdestructor)(T *obj);

    TeIntrusivePtr() : _p(nullptr), _deleteFn(nullptr) {}

    TeIntrusivePtr(const TeIntrusivePtr<T> &other) : _deleteFn(nullptr) {
        _p = other._p;
        if (_p)
            _p->incrementCounter();
    }

    TeIntrusivePtr(T *obj) : _deleteFn(nullptr) {
        _p = obj;
        if (_p)
            _p->incrementCounter();
    }

    virtual ~TeIntrusivePtr() {
        release();
    }

    TeIntrusivePtr<T> &operator=(T *obj) {
        if (_p != obj) {
            release();
            _p = obj;
            if (_p)
                _p->incrementCounter();
        }
        return *this;
    }

    TeIntrusivePtr<T> &operator=(const TeIntrusivePtr<T> &other) {
        if (this != &other) {
            release();
            _p = other._p;
            _deleteFn = other._deleteFn;
            if (_p)
                _p->incrementCounter();
        }
        return *this;
    }

    void release() {
        if (_p) {
            if (_p->decrementCounter()) {
                if (_deleteFn)
                    (_deleteFn)(_p);
                else
                    delete _p;
            }
        }
        _p = nullptr;
    }

    bool operator==(const TeIntrusivePtr<T> &other) const {
        return (this == &other || _p == other._p);
    }

    T *get() {
        return _p;
    }

    const T *get() const {
        return _p;
    }

    T &operator*() {
        return *_p;
    }

    const T &operator*() const {
        return *_p;
    }

    operator bool() const {
        return _p != nullptr;
    }

    T *operator->() {
        return _p;
    }

    const T *operator->() const {
        return _p;
    }

    void setDeleteFn(Tdestructor destructor) {
        _deleteFn = destructor;
    }

private:
    T *_p;
    Tdestructor _deleteFn;
};

} // end namespace Tetraedge

#endif // TETRAEDGE_TE_TE_INTRUSIVE_PTR_H