#ifndef WTF_WeakPtr_h
#define WTF_WeakPtr_h
#include <wtf/Noncopyable.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefPtr.h>
#include <wtf/ThreadSafeRefCounted.h>
#include <wtf/Threading.h>
#if USE(WEB_THREAD)
#include <wtf/MainThread.h>
#endif
namespace WTF {
template<typename T>
class WeakReference : public ThreadSafeRefCounted<WeakReference<T>> {
WTF_MAKE_NONCOPYABLE(WeakReference<T>);
WTF_MAKE_FAST_ALLOCATED;
public:
static PassRefPtr<WeakReference<T>> create(T* ptr) { return adoptRef(new WeakReference(ptr)); }
static PassRefPtr<WeakReference<T>> createUnbound() { return adoptRef(new WeakReference()); }
T* get() const
{
#if USE(WEB_THREAD)
ASSERT(canAccessThreadLocalDataForThread(m_boundThread));
#else
ASSERT(m_boundThread == currentThread());
#endif
return m_ptr;
}
void clear()
{
#if USE(WEB_THREAD)
ASSERT(canAccessThreadLocalDataForThread(m_boundThread));
#else
ASSERT(m_boundThread == currentThread());
#endif
m_ptr = 0;
}
void bindTo(T* ptr)
{
ASSERT(!m_ptr);
#ifndef NDEBUG
m_boundThread = currentThread();
#endif
m_ptr = ptr;
}
private:
WeakReference() : m_ptr(0) { }
explicit WeakReference(T* ptr)
: m_ptr(ptr)
#ifndef NDEBUG
, m_boundThread(currentThread())
#endif
{
}
T* m_ptr;
#ifndef NDEBUG
ThreadIdentifier m_boundThread;
#endif
};
template<typename T>
class WeakPtr {
WTF_MAKE_FAST_ALLOCATED;
public:
WeakPtr() { }
WeakPtr(PassRefPtr<WeakReference<T>> ref) : m_ref(ref) { }
T* get() const { return m_ref->get(); }
explicit operator bool() const { return m_ref->get(); }
T* operator->() const { return m_ref->get(); }
private:
RefPtr<WeakReference<T>> m_ref;
};
template<typename T>
class WeakPtrFactory {
WTF_MAKE_NONCOPYABLE(WeakPtrFactory<T>);
WTF_MAKE_FAST_ALLOCATED;
public:
explicit WeakPtrFactory(T* ptr) : m_ref(WeakReference<T>::create(ptr)) { }
WeakPtrFactory(PassRefPtr<WeakReference<T>> ref, T* ptr)
: m_ref(ref)
{
m_ref->bindTo(ptr);
}
~WeakPtrFactory() { m_ref->clear(); }
WeakPtr<T> createWeakPtr() { return WeakPtr<T>(m_ref); }
void revokeAll()
{
T* ptr = m_ref->get();
m_ref->clear();
m_ref = WeakReference<T>::create(ptr);
}
private:
RefPtr<WeakReference<T>> m_ref;
};
}
using WTF::WeakPtr;
using WTF::WeakPtrFactory;
using WTF::WeakReference;
#endif