access.h

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// Copyright (C) 2006-2014 David Sugar, Tycho Softworks.
// Copyright (C) 2015 Cherokees of Idaho.
//
// This file is part of GNU uCommon C++.
//
// GNU uCommon C++ is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU uCommon C++ 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with GNU uCommon C++.  If not, see <http://www.gnu.org/licenses/>.
 
// we do this twice because of some bizarre issue in just this file that
// otherwise breaks doxygen and lists all items outside the namespace...
#include <ucommon/platform.h>
 
#ifndef _UCOMMON_ACCESS_H_
#define _UCOMMON_ACCESS_H_
 
#ifndef _UCOMMON_CPR_H_
#include <ucommon/cpr.h>
#endif
 
#ifndef _UCOMMON_PROTOCOLS_H_
#include <ucommon/protocols.h>
#endif
 
namespace ucommon {
 
class __EXPORT ExclusiveProtocol
{
protected:
    virtual ~ExclusiveProtocol();
 
    virtual void _lock(void) = 0;
 
    virtual void _unlock(void) = 0;
 
public:
    class __EXPORT Locking
    {
    private:
        ExclusiveProtocol *lock;
 
        __DELETE_COPY(Locking);
 
    public:
        Locking(ExclusiveProtocol *object);
 
        ~Locking();
 
        inline bool operator!() const {
            return lock == NULL;
        }
 
        inline operator bool() const {
            return lock != NULL;
        }
 
        void release(void);
    };
};
 
class __EXPORT SharedProtocol
{
protected:
    virtual ~SharedProtocol();
 
    virtual void _share(void) = 0;
 
    virtual void _unshare(void) = 0;
 
public:
    class __EXPORT Locking
    {
    private:
        SharedProtocol *lock;
        int state;
        bool modify;
 
    public:
        Locking(SharedProtocol *object);
 
        Locking(const Locking& copy);
 
        Locking& operator=(const Locking& copy);
 
        ~Locking();
 
        inline bool operator!() const {
            return lock == NULL;
        }
 
        inline operator bool() const {
            return lock != NULL;
        }
 
        void release(void);
 
        void exclusive(void);
 
        void share(void);
    };
 
    virtual void share(void);
 
    virtual void exclusive(void);
};
 
class __EXPORT shared_access
{
private:
    SharedProtocol *lock;
    int state;
    bool modify;
 
public:
    shared_access(SharedProtocol *object);
 
    shared_access(const shared_access& copy);
 
    shared_access& operator=(const shared_access& copy);
 
    ~shared_access();
 
    inline bool operator!() const {
        return lock == NULL;
    }
 
    inline operator bool() const {
        return lock != NULL;
    }
 
    void release(void);
 
    void exclusive(void);
 
    void share(void);
};
 
template<class T>
class autoexclusive : private ExclusiveProtocol::Locking
{
private:
    __DELETE_DEFAULTS(autoexclusive);
 
public:
    inline autoexclusive(T *lock) :
    Locking(polystatic_cast<ExclusiveProtocol *>(lock)) {};
};
 
template<class T>
class autoshared : private SharedProtocol::Locking
{
private:
    __DELETE_DEFAULTS(autoshared);
 
public:
    inline autoshared(T *lock) :
    Locking(polystatic_cast<SharedProtocol *>(lock)) {};
};
 
// Special macros to allow member functions of an object with a protocol
// to create self locking states while the member functions are called by
// placing an exclusive_lock or shared_lock smart object on their stack
// frame to reference their self.
 
#define __EXCLUSIVE(x) exclusive_access __autolock__ = x
#define __SHARE(x) shared_access __autolock__ = x
 
} // namespace ucommon
 
#endif