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#ifndef DEBUGGER_CALLBACK_H

#define DEBUGGER_CALLBACK_H

#include <QtCore/QtGlobal>

namespace trk {

namespace Internal {

/* Helper class for the 1-argument functor:

 * Cloneable base class for the implementation which is

 * invokeable with the argument. */

template <class Argument>

class CallbackImplBase

{

    Q_DISABLE_COPY(CallbackImplBase)

public:

    CallbackImplBase() {}

    virtual CallbackImplBase *clone() const = 0;

    virtual void invoke(Argument a) = 0;

    virtual ~CallbackImplBase() {}

};

/* Helper class for the 1-argument functor: Implementation for

 * a class instance with a member function pointer. */

template <class Class, class Argument>

class CallbackMemberPtrImpl : public CallbackImplBase<Argument>

{

public:

    typedef void (Class::*MemberFuncPtr)(Argument);

    CallbackMemberPtrImpl(Class *instance,

                          MemberFuncPtr memberFunc) :

                          m_instance(instance),

                          m_memberFunc(memberFunc) {}

    virtual CallbackImplBase<Argument> *clone() const

    {

        return new CallbackMemberPtrImpl<Class, Argument>(m_instance, m_memberFunc);

    }

    virtual void invoke(Argument a)

        { (m_instance->*m_memberFunc)(a); }

private:

    Class *m_instance;

    MemberFuncPtr m_memberFunc;

};

} // namespace Internal

/* Default-constructible, copyable 1-argument functor providing an

 * operator()(Argument) that invokes a member function of a class:

 * \code

class Foo {

public:

    void print(const std::string &);

};

...

Foo foo;

Callback<const std::string &> f1(&foo, &Foo::print);

f1("test");

\endcode */

template <class Argument>

class Callback

{

public:

    Callback() : m_impl(0) {}

    template <class Class>

    Callback(Class *instance, void (Class::*memberFunc)(Argument)) :

        m_impl(new Internal::CallbackMemberPtrImpl<Class,Argument>(instance, memberFunc))

    {}

    ~Callback()

    {

        clean();

    }

    Callback(const Callback &rhs) :

        m_impl(0)

    {

        if (rhs.m_impl)

            m_impl = rhs.m_impl->clone();

    }

    Callback &operator=(const Callback &rhs)

    {

        if (this != &rhs) {

            clean();

            if (rhs.m_impl)

                m_impl = rhs.m_impl->clone();

        }

        return *this;

    }

    bool isNull() const { return m_impl == 0; }

    operator bool() const { return !isNull(); }

    void operator()(Argument a)

    {

        if (m_impl)

            m_impl->invoke(a);

    }

private:

    void clean()

    {

        if (m_impl) {

            delete m_impl;

            m_impl = 0;

        }

    }

    Internal::CallbackImplBase<Argument> *m_impl;

};

} // namespace trk

#endif // DEBUGGER_CALLBACK_H