subject.h

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#line 1 "S:/jenkins/workspace/ECP/ufe/ufe-full-python3.10-windows/ufe/include/subject.h"
#ifndef _ufeSubject
#define _ufeSubject
// ===========================================================================
// Copyright 2018 Autodesk, Inc. All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk license
// agreement provided at the time of installation or download, or which
// otherwise accompanies this software in either electronic or hard copy form.
// ===========================================================================

#include "observer.h"

#include <set>

UFE_NS_DEF {

class Notification;
class NotificationGuard;


class UFE_SDK_DECL Subject
{
public:

    Subject();
    
    Subject(const Subject&);

    Subject(Subject&&);

    virtual ~Subject();

    Subject& operator=(const Subject&);

    Subject& operator=(Subject&&);

    bool addObserver(const Observer::Ptr& obs);

    bool removeObserver(const Observer::Ptr& obs);

    bool hasObserver(const Observer::Ptr& obs) const;

    std::size_t nbObservers() const;

    virtual void notify(const Notification& notification);

    virtual bool inCompositeNotification() const;

protected:
    virtual void beginNotificationGuard();
    virtual void endNotificationGuard();

private:
    friend class NotificationGuard;

    // Weak pointers cannot be ordered by default, as they can expire at any
    // time.  However, they can be ordered by the address of the control block,
    // which stores the number of shared_ptr AND weak_ptr, and is deleted only
    // when the last weak_ptr expires.
    typedef std::set<Observer::WeakPtr, std::owner_less<Observer::WeakPtr> >
        Observers;

    void cleanObservers(const Observers& dead);

    Observers fObservers;
};


class UFE_SDK_DECL NotificationGuard {
public:

    NotificationGuard(Subject& subject);
    ~NotificationGuard();

    NotificationGuard(const NotificationGuard&) = delete;
    const NotificationGuard& operator&(const NotificationGuard&) = delete;

private:
    Subject* const fSubject;
};

}

#endif /* _ufeSubject */