---

PtrUsageSharing.hh

Go to the documentation of this file.

#ifndef MANGO_USAGE_SHARING_H
#define MANGO_USAGE_SHARING_H

#include "ValidityOwner.hh"  // contain

namespace MangoPtrPrivateNamespace
{
class PtrUsageSharing
{
    protected:
        PtrUsageSharing(): initialized(false) {}
        PtrUsageSharing(const PtrUsageSharing& rhs)
            : usageVal(rhs.usageVal)
        {
            assert(usageVal.isShared());
            assert(rhs.initialized);
            initialized = true;
        }
        void operator=(const PtrUsageSharing& rhs) 
        {
            assert(rhs.initialized);
            initialized = true;

            usageVal = rhs.usageVal;
            assert(usageVal.isShared());
        }
        void swap(PtrUsageSharing& rhs) 
        {
            usageVal.swap(rhs.usageVal);
            std::swap(initialized, rhs.initialized);
        }

    public:
        void invalidateUsage() { usageVal.setValid(false); }
        void unlinkNew() 
        {
            if (initialized) // optimized
            {
                // don't bother resetting if not shared
                usageVal.reset(false);
                // else don't care
                initialized = false;
            }
            else 
            {
                // uninitialized ==> invalid (default state)
                assert(! usageVal.isValid());
                // also implies has never been shared since sharing 
                // requires initialization
                assert(! usageVal.isShared());
            }
        }
        const MangoPtr::ValidityOwner& usage() const 
        {
            assert(initialized);
            return usageVal;
        }

    protected:
        void setFrom(void* optr)
        {
            if (!initialized) 
            {
                usageVal.setValid( MangoPtr::isNotNull(optr) );
                initialized = true;
            }
        }
        bool wasUsageInitialized() const {return initialized;}

    protected:
        MangoPtr::ValidityOwner usageVal; 

    private:
        bool initialized; 
};
    
}  // end namespace MangoPtrPrivateNamespace
 
#endif // MANGO_USAGE_SHARING_H

---