Handle.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 QDENGINE_QDCORE_UTIL_HANDLE_H
#define QDENGINE_QDCORE_UTIL_HANDLE_H


namespace QDEngine {

// Автоматически удаляемый указатель
template<class T>
class PtrHandle {
public:
    PtrHandle(T *p = 0) : ptr(p) {}
    PtrHandle(PtrHandle &p) : ptr(p.release()) {}
    ~PtrHandle() {
        delete ptr;
    }

    void set(T *p) {
        ptr = p;
    }

    PtrHandle &operator=(PtrHandle &p) {
        if (get() != p.get()) {
            delete ptr;
            ptr = p.release();
        }
        return *this;
    }

    PtrHandle &operator=(T *p) {
        if (get() != p)
            delete ptr;
        set(p);
        return *this;
    }

    T *get() const {
        return ptr;
    }
    T *release() {
        T *tmp = ptr;
        ptr = 0;
        return tmp;
    }

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

private:
    T *ptr;
};

// Автоматически удаляемый указатель
// с отслеживанием владельцев.
// Обекты должны наследовать ShareHandleBase
template<class T>
class ShareHandle {
public:
    ShareHandle(T *p = 0) {
        set(p);
    }
    ShareHandle(const ShareHandle &orig) {
        set(orig.ptr);
    }

    ~ShareHandle() {
        if (ptr && !ptr->decrRef())
            delete ptr;
    }

    void set(T *p) {
        ptr = p;
        if (p)
            p->addRef();
    }

    ShareHandle &operator=(const ShareHandle &orig) {
        if (ptr && !ptr->decrRef() && ptr != orig.ptr)
            delete ptr;
        set(orig.ptr);
        return *this;
    }

    ShareHandle &operator=(T *p) {
        if (ptr && !ptr->decrRef() && ptr != p)
            delete ptr;
        set(p);
        return *this;
    }

    T *get() const {
        return ptr;
    }
    T *release() {
        T *tmp = ptr;
        if (ptr) ptr->decrRef();
        ptr = 0;
        return tmp;
    }

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

private:
    T *ptr;
};

class ShareHandleBase {
public:
    ShareHandleBase() {
        handleCount = 0;
    }
    ShareHandleBase(const ShareHandleBase &) {
        handleCount = 0;
    }
    ~ShareHandleBase() {}
    void addRef() {
        ++handleCount;
    }
    int decrRef() {
        return --handleCount;
    }
    int numRef() const {
        return handleCount;
    }

private:
    mutable int handleCount;
};

} // namespace QDEngine

#endif // QDENGINE_QDCORE_UTIL_HANDLE_H