/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2008 INRIA
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
*/
#ifndef ATTRIBUTE_H
#define ATTRIBUTE_H
#include <string>
#include <stdint.h>
#include "ptr.h"
#include "object-base.h"
namespace ns3 {
class AttributeAccessor;
class AttributeChecker;
class Attribute;
/**
* \brief Hold a value for an Attribute.
*
* Instances of this class are usually created by Attribute::Create<> and
* should always be wrapped into an Attribute object.
* Most subclasses of this base class are implemented by the
* ATTRIBUTE_HELPER_* macros.
*/
class AttributeValue
{
public:
AttributeValue ();
AttributeValue (const AttributeValue &o);
AttributeValue &operator = (const AttributeValue &o);
virtual ~AttributeValue ();
/**
* \returns a deep copy of this class, wrapped into an Attribute object.
*/
virtual Attribute Copy (void) const = 0;
/**
* \param checker the checker associated to the attribute
* \returns a string representation of this value.
*
* In most cases, this method will not make any use of the checker argument.
* However, in a very limited set of cases, the checker argument is needed to
* perform proper serialization. A nice example of code which needs it is
* the EnumValue::SerializeToString code.
*/
virtual std::string SerializeToString (Ptr<const AttributeChecker> checker) const = 0;
/**
* \param value a string representation of the value
* \param checker a pointer to the checker associated to the attribute.
* \returns true if the input string was correctly-formatted and could be
* successfully deserialized, false otherwise.
*
* Upon return of this function, this AttributeValue instance contains
* the deserialized value.
* In most cases, this method will not make any use of the checker argument.
* However, in a very limited set of cases, the checker argument is needed to
* perform proper serialization. A nice example of code which needs it is
* the EnumValue::SerializeToString code.
*/
virtual bool DeserializeFromString (std::string value, Ptr<const AttributeChecker> checker) = 0;
private:
friend class Attribute;
uint32_t m_count;
};
/**
* \brief an opaque wrapper around a value to set or retrieved
* from an attribute.
*
* This class is really a smart pointer to an instance of AttributeValue.
* Of course, the question is "why not use a Ptr<AttributeValue>" ?. The
* answer is long and complicated but the crux of the issue is that if we
* do not reproduce the smart pointer code in this class, we cannot provide
* transparent handling of Ptr<T> values through the attribute system.
*/
class Attribute
{
public:
Attribute ();
Attribute (const Attribute &o);
Attribute &operator = (const Attribute &o);
~Attribute ();
/**
* Forward to AttributeValue::Copy
*/
Attribute Copy (void) const;
/**
* Forward to AttributeValue::SerializeToString
*/
std::string SerializeToString (Ptr<const AttributeChecker> checker) const;
/**
* Forward to AttributeValue::DeserializeFromString
*/
bool DeserializeFromString (std::string value, Ptr<const AttributeChecker> checker);
/**
* \returns a new Attribute object which wraps an instance of the requested
* subclass of AttributeValue.
*/
template <typename T>
static Attribute Create (void);
/**
* \param a1 a value to pass through to the constructor of the class T.
* \returns a new Attribute object which wraps an instance of the requested
* subclass of AttributeValue.
*/
template <typename T, typename T1>
static Attribute Create (T1 a1);
/**
* This method performs a dynamic_cast on the underlying AttributeValue.
* This method is typically used to implement conversion operators
* from the type Attribute. In most cases, these conversion operators
* will be generated for you by the ATTRIBUTE_HELPER_* macros.
* \returns the casted pointer.
*/
template <typename T>
T DynCast (void) const;
/**
* \param pointer a pointer to convert into an Attribute.
*/
template <typename T>
Attribute (Ptr<T> pointer);
/**
* \returns a pointer converted from this Attribute instance.
*/
template <typename T>
operator Ptr<T> ();
private:
Attribute (AttributeValue *value);
AttributeValue *m_value;
};
/**
* \brief allow setting and getting the value of an attribute.
*
* The goal of this class is to hide from the user how an attribute
* is actually set or get to or from a class instance. Implementations
* of this base class are usually provided through the MakeAccessorHelper
* template functions, hidden behind an ATTRIBUTE_HELPER_* macro.
*/
class AttributeAccessor : public ObjectBase
{
public:
AttributeAccessor ();
void Ref (void) const;
void Unref (void) const;
virtual ~AttributeAccessor ();
/**
* \param object the object instance to set the value in
* \param value the value to set
* \returns true if the value could be set successfully, false otherwise.
*
* This method expects that the caller has checked that the input value is
* valid with AttributeChecker::Check.
*/
virtual bool Set (ObjectBase * object, Attribute value) const = 0;
/**
* \param object the object instance to get the value from
* \param attribute a pointer to where the value should be set.
* \returns true if the value could be read successfully, and
* stored in the input value, false otherwise.
*
* This method expects that the caller has checked that the input value is
* valid with AttributeChecker::Check.
*/
virtual bool Get (const ObjectBase * object, Attribute attribute) const = 0;
private:
mutable uint32_t m_count;
};
/**
* \brief Represent the type of an attribute
*
* Each type of attribute has an associated unique AttributeChecker
* subclass. The type of the subclass can be safely used by users
* to infer the type of the associated attribute. i.e., we expect
* binding authors to use the checker associated to an attribute
* to detect the type of the associated attribute.
*
* Most subclasses of this base class are implemented by the
* ATTRIBUTE_HELPER_* macros.
*/
class AttributeChecker : public ObjectBase
{
public:
AttributeChecker ();
void Ref (void) const;
void Unref (void) const;
virtual ~AttributeChecker ();
/**
* \param value a pointer to the value to check
* \returns true if the input value is both of the right type
* and if its value is within the requested range. Returns
* false otherwise.
*/
virtual bool Check (Attribute value) const = 0;
/**
* \returns a new instance of an AttributeValue (wrapper in an Attribute
* instance) which matches the type of the underlying attribute.
*
* This method is typically used to create a temporary variable prior
* to calling Attribute::DeserializeFromString.
*/
virtual Attribute Create (void) const = 0;
private:
mutable uint32_t m_count;
};
template <typename T, typename BASE>
Ptr<AttributeChecker>
MakeSimpleAttributeChecker (void);
template <typename T, typename U>
Ptr<const AttributeAccessor>
MakePtrAccessor (Ptr<U> T::*memberVariable);
template <typename T, typename U>
Ptr<const AttributeAccessor>
MakePtrAccessor (void (T::*setter) (Ptr<U>));
template <typename T, typename U>
Ptr<const AttributeAccessor>
MakePtrAccessor (Ptr<U> (T::*getter) (void) const);
class PtrChecker : public AttributeChecker {};
template <typename T>
Ptr<AttributeChecker> MakePtrChecker (void);
} // namespace ns3
namespace ns3 {
/********************************************************
* The class used to access the pointer stored in a
* PtrValue<T> AttributeValue instance.
********************************************************/
class PtrValueBase : public AttributeValue
{
public:
virtual ObjectBase *PeekObjectBase (void) const = 0;
virtual bool SetObjectBase (ObjectBase *object) = 0;
virtual std::string SerializeToString (Ptr<const AttributeChecker> checker) const;
virtual bool DeserializeFromString (std::string value, Ptr<const AttributeChecker> checker);
};
/********************************************************
* Store the content of a Ptr<T> in a AttributeValue
********************************************************/
namespace internal {
template <typename T>
class PtrValue : public PtrValueBase
{
public:
PtrValue ()
: m_pointer () {}
PtrValue (Ptr<T> pointer)
: m_pointer (pointer) {}
virtual ObjectBase *PeekObjectBase (void) const {
return PeekPointer (m_pointer);
}
virtual bool SetObjectBase (ObjectBase *object) {
T *ptr = dynamic_cast<T *> (object);
if (ptr == 0)
{
return false;
}
m_pointer = ptr;
return true;
}
virtual Attribute Copy (void) const {
return Attribute::Create<PtrValue<T> > (*this);
}
private:
Ptr<T> m_pointer;
};
template <typename T>
class APtrChecker : public PtrChecker
{
virtual bool Check (Attribute val) const {
const PtrValueBase *value = val.DynCast<const PtrValueBase *> ();
if (value == 0)
{
return false;
}
if (value->PeekObjectBase () == 0)
{
return true;
}
T *ptr = dynamic_cast<T*> (value->PeekObjectBase ());
if (ptr == 0)
{
return false;
}
return true;
}
virtual Attribute Create (void) const {
return Attribute::Create<PtrValue<T> > ();
}
};
/********************************************************
* The Accessor associated to
* PtrValue<T>
********************************************************/
template <typename T, typename U>
class PtrAccessor : public AttributeAccessor
{
public:
virtual ~PtrAccessor () {}
virtual bool Set (ObjectBase * object, Attribute val) const {
T *obj = dynamic_cast<T *> (object);
if (obj == 0)
{
return false;
}
const PtrValueBase *value = val.DynCast<const PtrValueBase *> ();
if (value == 0)
{
return false;
}
Ptr<U> ptr = dynamic_cast<U*> (value->PeekObjectBase ());
if (ptr == 0)
{
return false;
}
DoSet (obj, ptr);
return true;
}
virtual bool Get (const ObjectBase * object, Attribute val) const {
const T *obj = dynamic_cast<const T *> (object);
if (obj == 0)
{
return false;
}
PtrValueBase *value = val.DynCast<PtrValueBase *> ();
if (value == 0)
{
return false;
}
return value->SetObjectBase (PeekPointer (DoGet (obj)));
}
private:
virtual void DoSet (T *object, Ptr<U> value) const = 0;
virtual Ptr<U> DoGet (const T *object) const = 0;
};
} // namespace internal
/********************************************************
* The implementation of the Attribute
* class template methods.
********************************************************/
template <typename T>
Attribute
Attribute::Create (void)
{
return Attribute (new T ());
}
template <typename T, typename T1>
Attribute
Attribute::Create (T1 a1)
{
return Attribute (new T (a1));
}
template <typename T>
T
Attribute::DynCast (void) const
{
return dynamic_cast<T> (m_value);
}
template <typename T>
Attribute::Attribute (Ptr<T> pointer)
: m_value (new internal::PtrValue<T> (pointer))
{}
template <typename T>
Attribute::operator Ptr<T> ()
{
PtrValueBase *value = DynCast<PtrValueBase *> ();
if (value == 0)
{
return 0;
}
ObjectBase *objectBase = value->PeekObjectBase ();
T *obj = dynamic_cast<T *> (objectBase);
if (obj == 0)
{
return 0;
}
return obj;
}
template <typename T, typename U>
Ptr<const AttributeAccessor>
MakePtrAccessor (Ptr<U> T::*memberVariable)
{
struct MemberVariable : public internal::PtrAccessor<T,U>
{
Ptr<U> T::*m_memberVariable;
virtual void DoSet (T *object, Ptr<U> value) const {
(object->*m_memberVariable) = value;
}
virtual Ptr<U> DoGet (const T *object) const {
return object->*m_memberVariable;
}
} *spec = new MemberVariable ();
spec->m_memberVariable = memberVariable;
return Ptr<const AttributeAccessor> (spec, false);
}
template <typename T, typename U>
Ptr<const AttributeAccessor>
MakePtrAccessor (void (T::*setter) (Ptr<U>))
{
struct MemberMethod : public internal::PtrAccessor<T,U>
{
void (T::*m_setter) (Ptr<U>);
virtual void DoSet (T *object, Ptr<U> value) const {
(object->*m_setter) (value);
}
virtual Ptr<U> DoGet (const T *object) const {
return 0;
//return (object->*m_getter) ();
}
} *spec = new MemberMethod ();
spec->m_setter = setter;
return Ptr<const AttributeAccessor> (spec, false);
}
template <typename T, typename U>
Ptr<const AttributeAccessor>
MakePtrAccessor (Ptr<U> (T::*getter) (void) const)
{
struct MemberMethod : public internal::PtrAccessor<T,U>
{
Ptr<U> (T::*m_getter) (void) const;
virtual void DoSet (T *object, Ptr<U> value) const {
//(object->*m_setter) (value);
}
virtual Ptr<U> DoGet (const T *object) const {
return (object->*m_getter) ();
}
} *spec = new MemberMethod ();
spec->m_getter = getter;
return Ptr<const AttributeAccessor> (spec, false);
}
template <typename T>
Ptr<AttributeChecker>
MakePtrChecker (void)
{
return Create<internal::APtrChecker<T> > ();
}
template <typename T, typename BASE>
Ptr<AttributeChecker>
MakeSimpleAttributeChecker (void)
{
struct SimpleAttributeChecker : public BASE
{
virtual bool Check (Attribute value) const {
return value.DynCast<const T *> () != 0;
}
virtual Attribute Create (void) const {
return Attribute::Create<T> ();
}
} *checker = new SimpleAttributeChecker ();
return Ptr<AttributeChecker> (checker, false);
}
} // namespace ns3
#endif /* ATTRIBUTE_H */