/*
 * Copyright 2009, Axel Dörfler, axeld@pinc-software.de.
 * Distributed under the terms of the MIT License.
 */


#include <WeakReferenceable.h>

#include <stdio.h>
#include <OS.h>


namespace BPrivate {


WeakPointer::WeakPointer(BWeakReferenceable* object)
        :
        fUseCount(1),
        fObject(object)
{
}


WeakPointer::~WeakPointer()
{
}


BWeakReferenceable*
WeakPointer::Get()
{
        int32 count;
        do {
                count = atomic_get(&fUseCount);
                if (count == 0)
                        return NULL;
                if (count < 0)
                        debugger("reference (use) count is negative");
        } while (atomic_test_and_set(&fUseCount, count + 1, count) != count);

        return fObject;
}


bool
WeakPointer::Put()
{
        const int32 count = atomic_add(&fUseCount, -1);
        if (count == 1) {
                delete fObject;
                return true;
        }
        if (count <= 0)
                debugger("reference (use) count is negative");

        return false;
}


int32
WeakPointer::UseCount() const
{
        return fUseCount;
}


void
WeakPointer::GetUnchecked()
{
        atomic_add(&fUseCount, 1);
}


//      #pragma -


BWeakReferenceable::BWeakReferenceable()
        :
        fPointer(new(std::nothrow) WeakPointer(this))
{
}


BWeakReferenceable::~BWeakReferenceable()
{
        if (fPointer->UseCount() == 1)
                atomic_test_and_set(&fPointer->fUseCount, 0, 1);

        if (fPointer->UseCount() != 0) {
                char message[256];
                snprintf(message, sizeof(message), "deleting referenceable object %p with "
                        "reference count (%" B_PRId32 ")", this, fPointer->UseCount());
                debugger(message);
        }

        fPointer->ReleaseReference();
}


status_t
BWeakReferenceable::InitCheck()
{
        if (fPointer == NULL)
                return B_NO_MEMORY;
        return B_OK;
}


WeakPointer*
BWeakReferenceable::GetWeakPointer()
{
        fPointer->AcquireReference();
        return fPointer;
}


}       // namespace BPrivate