Files
unison/src/core/model/ptr.h
2022-08-18 17:53:33 +00:00

818 lines
19 KiB
C++

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2005,2006 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
*
* Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
*/
#ifndef PTR_H
#define PTR_H
#include "assert.h"
#include "deprecated.h"
#include <iostream>
#include <stdint.h>
/**
* \file
* \ingroup ptr
* ns3::Ptr smart pointer declaration and implementation.
*/
namespace ns3 {
/**
* \ingroup core
* \defgroup ptr Smart Pointer
* \brief Heap memory management.
*
* See \ref ns3::Ptr for implementation details.
*
* See \ref main-ptr.cc for example usage.
*/
/**
* \ingroup ptr
*
* \brief Smart pointer class similar to \c boost::intrusive_ptr.
*
* This smart-pointer class assumes that the underlying
* type provides a pair of \c Ref() and \c Unref() methods which are
* expected to increment and decrement the internal reference count
* of the object instance. You can add \c Ref() and \c Unref()
* to a class simply by inheriting from ns3::SimpleRefCount<>
* using the CRTP (`class Foo : public SimpleRefCount<Foo>`)
*
* This implementation allows you to manipulate the smart pointer
* as if it was a normal pointer: you can test if it is non-null,
* compare it to other pointers of the same type, etc.
*
* It is possible to extract the raw pointer from this
* smart pointer with the GetPointer() and PeekPointer() methods.
*
* If you want to store a `new Object()` into a smart pointer,
* we recommend you to use the CreateObject<>() template function
* to create the Object and store it in a smart pointer to avoid
* memory leaks. These functions are really small convenience
* functions and their goal is just is save you a small
* bit of typing. If the Object does not inherit from Object
* (or ObjectBase) there is also a convenience wrapper Create<>()
*
* \tparam T \explicit The type of the underlying object.
*/
template <typename T>
class Ptr
{
private:
/** The pointer. */
T *m_ptr;
/**
* Helper to test for null pointer.
*
* \note This has been deprecated; \see operator bool() instead.
*
* This supports the "safe-bool" idiom, see `operator Tester * ()`
*/
// Don't deprecate the class because the warning fires
// every time ptr.h is merely included, masking the real uses of Tester
// Leave the macro here so we can find this later to actually remove it.
class /* NS_DEPRECATED_3_37 ("see operator bool") */ Tester
{
public:
// Delete operator delete to avoid misuse
void operator delete (void *) = delete;
};
/** Interoperate with const instances. */
friend class Ptr<const T>;
/**
* Get a permanent pointer to the underlying object.
*
* The underlying refcount is incremented prior
* to returning to the caller so the caller is
* responsible for calling Unref himself.
*
* \tparam U \deduced The actual type of the argument and return pointer.
* \param [in] p Smart pointer
* \return The pointer managed by this smart pointer.
*/
template <typename U>
friend U * GetPointer (const Ptr<U> &p);
/**
* Get a temporary pointer to the underlying object.
*
* The underlying refcount is not incremented prior
* to returning to the caller so the caller is not
* responsible for calling Unref himself.
*
* \tparam U \deduced The actual type of the argument and return pointer.
* \param [in] p Smart pointer
* \return The pointer managed by this smart pointer.
*/
template <typename U>
friend U * PeekPointer (const Ptr<U> &p);
/** Mark this as a a reference by incrementing the reference count. */
inline void Acquire (void) const;
public:
/** Create an empty smart pointer */
Ptr ();
/**
* Create a smart pointer which points to the object pointed to by
* the input raw pointer ptr. This method creates its own reference
* to the pointed object. The caller is responsible for Unref()'ing
* its own reference, and the smart pointer will eventually do the
* same, so that object is deleted if no more references to it
* remain.
*
* \param [in] ptr Raw pointer to manage
*/
Ptr (T *ptr);
/**
* Create a smart pointer which points to the object pointed to by
* the input raw pointer ptr.
*
* \param [in] ptr Raw pointer to manage
* \param [in] ref if set to true, this method calls Ref, otherwise,
* it does not call Ref.
*/
Ptr (T *ptr, bool ref);
/**
* Copy by referencing the same underlying object.
*
* \param [in] o The other Ptr instance.
*/
Ptr (Ptr const&o);
/**
* Copy, removing \c const qualifier.
*
* \tparam U \deduced The type underlying the Ptr being copied.
* \param [in] o The Ptr to copy.
*/
template <typename U>
Ptr (Ptr<U> const &o);
/** Destructor. */
~Ptr ();
/**
* Assignment operator by referencing the same underlying object.
*
* \param [in] o The other Ptr instance.
* \return A reference to self.
*/
Ptr<T> &operator = (Ptr const& o);
/**
* An rvalue member access.
* \returns A pointer to the underlying object.
*/
T *operator -> () const;
/**
* An lvalue member access.
* \returns A pointer to the underlying object.
*/
T *operator -> ();
/**
* A \c const dereference.
* \returns A pointer to the underlying object.
*/
T &operator * () const;
/**
* A dereference.
* \returns A pointer to the underlying object.
*/
T &operator * ();
/**
* Test for non-NULL Ptr.
*
* \note This has been deprecated; \see operator bool() instead.
*
* This enables simple pointer checks like
* \code
* Ptr<...> p = ...;
* if (p) ...
* \endcode
* This also disables deleting a Ptr
*
* This supports the "safe-bool" idiom; see [More C++ Idioms/Safe bool](https://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Safe_bool)
*/
NS_DEPRECATED_3_37 ("see operator bool")
operator Tester * () const;
/**
* Test for non-NULL pointer.
*
* This enables simple pointer checks like
* \code
* Ptr<...> p = ...;
* if (p) ...
* if (!p) ...
* \endcode
*
* The same construct works in the NS_ASSERT... and NS_ABORT... macros.
*
* \note Explicit tests against `0`, `NULL` or `nullptr` are not supported.
* All these cases will fail to compile:
* \code
* if (p != 0) {...} // Should be `if (p)`
* if (p != NULL) {...}
* if (p != nullptr {...}
*
* if (p == 0) {...} // Should be `if (!p)`
* if (p == NULL) {...}
* if (p == nullptr {...}
* \endcode
* Just use `if (p)` or `if (!p)` as indicated.
*
* \note NS_TEST... invocations should be written as follows:
* \code
* // p should be non-NULL
* NS_TEST...NE... (p, nullptr, ...);
* // p should be NULL
* NS_TEST...EQ... (p, nullptr, ...);
* \endcode
*
* \note Unfortunately return values are not
* "contextual conversion expression" contexts,
* so you need to explicitly cast return values to bool:
* \code
* bool f (...)
* {
* Ptr<...> P = ...;
* return (bool)(p);
* }
* \endcode
*
* \returns \c true if the underlying pointer is non-NULL.
*/
explicit operator bool() const;
};
/**
* \ingroup ptr
* Create class instances by constructors with varying numbers
* of arguments and return them by Ptr.
*
* This template work for any class \c T derived from ns3::SimpleRefCount
*
* \see CreateObject for methods to create derivatives of ns3::Object
*/
/** @{ */
/**
* \tparam T \explicit The type of class object to create.
* \tparam Ts \deduced Types of the constructor arguments.
* \param [in] args Constructor arguments.
* \return A Ptr to the newly created \c T.
*/
template <typename T,
typename... Ts>
Ptr<T> Create (Ts&&... args);
/** @}*/
/**
* \ingroup ptr
* Output streamer.
* \tparam T \deduced The type of the underlying Object.
* \param [in,out] os The output stream.
* \param [in] p The Ptr.
* \returns The stream.
*/
template <typename T>
std::ostream &operator << (std::ostream &os, const Ptr<T> &p);
/**
* \ingroup ptr
* Equality operator.
*
* This enables code such as
* \code
* Ptr<...> p = ...;
* Ptr<...> q = ...;
* if (p == q) ...
* \endcode
*
* Note that either \c p or \c q could also be ordinary pointers
* to the underlying object.
*
* \tparam T1 \deduced Type of the object on the lhs.
* \tparam T2 \deduced Type of the object on the rhs.
* \param [in] lhs The left operand.
* \param [in] rhs The right operand.
* \return \c true if the operands point to the same underlying object.
*/
/** @{ */
template <typename T1, typename T2>
bool operator == (Ptr<T1> const &lhs, T2 const *rhs);
template <typename T1, typename T2>
bool operator == (T1 const *lhs, Ptr<T2> &rhs);
template <typename T1, typename T2>
bool operator == (Ptr<T1> const &lhs, Ptr<T2> const &rhs);
/** Specialization for comparison to nullptr */
template <typename T1, typename T2>
typename std::enable_if<std::is_same<T2, nullptr_t>::value, bool>::type
operator == (Ptr<T1> const &lhs, T2 nullPtr);
/**@}*/
/**
* \ingroup ptr
* Inequality operator.
*
* This enables code such as
* \code
* Ptr<...> p = ...;
* Ptr<...> q = ...;
* if (p != q) ...
* \endcode
*
* Note that either \c p or \c q could also be ordinary pointers
* to the underlying object.
*
* \tparam T1 \deduced Type of the object on the lhs.
* \tparam T2 \deduced Type of the object on the rhs.
* \param [in] lhs The left operand.
* \param [in] rhs The right operand.
* \return \c true if the operands point to the same underlying object.
*/
/** @{ */
template <typename T1, typename T2>
bool operator != (Ptr<T1> const &lhs, T2 const *rhs);
template <typename T1, typename T2>
bool operator != (T1 const *lhs, Ptr<T2> &rhs);
template <typename T1, typename T2>
bool operator != (Ptr<T1> const &lhs, Ptr<T2> const &rhs);
/** Specialization for comparison to nullptr */
template <typename T1, typename T2>
typename std::enable_if<std::is_same<T2, nullptr_t>::value, bool>::type
operator != (Ptr<T1> const &lhs, T2 nullPtr);
/**@}*/
/**
* \ingroup ptr
* Comparison operator applied to the underlying pointers.
*
* \tparam T \deduced The type of the operands.
* \param [in] lhs The left operand.
* \param [in] rhs The right operand.
* \return The comparison on the underlying pointers.
*/
/** @{ */
template <typename T>
bool operator < (const Ptr<T> &lhs, const Ptr<T> &rhs);
template <typename T>
bool operator< (const Ptr<T> &lhs, const Ptr<const T> &rhs);
template <typename T>
bool operator< (const Ptr<const T> &lhs, const Ptr<T> &rhs);
template <typename T>
bool operator<= (const Ptr<T> &lhs, const Ptr<T> &rhs);
template <typename T>
bool operator > (const Ptr<T> &lhs, const Ptr<T> &rhs);
template <typename T>
bool operator >= (const Ptr<T> &lhs, const Ptr<T> &rhs);
/** @} */
/**
* Return a copy of \c p with its stored pointer const casted from
* \c T2 to \c T1.
*
* \tparam T1 \deduced The type to return in a Ptr.
* \tparam T2 \deduced The type of the underlying object.
* \param [in] p The original \c const Ptr.
* \return A non-const Ptr.
*/
template <typename T1, typename T2>
Ptr<T1> const_pointer_cast (Ptr<T2> const&p);
// Duplicate of struct CallbackTraits<T> as defined in callback.h
template <typename T>
struct CallbackTraits;
/**
* \ingroup callbackimpl
*
* Trait class to convert a pointer into a reference,
* used by MemPtrCallBackImpl.
*
* This is the specialization for Ptr types.
*
* \tparam T \deduced The type of the underlying object.
*/
template <typename T>
struct CallbackTraits<Ptr<T> >
{
/**
* \param [in] p Object pointer
* \return A reference to the object pointed to by p
*/
static T & GetReference (Ptr<T> const p)
{
return *PeekPointer (p);
}
};
// Duplicate of struct EventMemberImplObjTraits<T> as defined in make-event.h
// We repeat it here to declare a specialization on Ptr<T>
// without making this header dependent on make-event.h
template <typename T>
struct EventMemberImplObjTraits;
/**
* \ingroup makeeventmemptr
* Helper for the MakeEvent functions which take a class method.
*
* This is the specialization for Ptr types.
*
* \tparam T \deduced The type of the underlying object.
*/
template <typename T>
struct EventMemberImplObjTraits<Ptr<T> >
{
/**
* \param [in] p Object pointer
* \return A reference to the object pointed to by p
*/
static T & GetReference (Ptr<T> p)
{
return *PeekPointer (p);
}
};
} // namespace ns3
namespace ns3 {
/*************************************************
* friend non-member function implementations
************************************************/
template <typename T, typename... Ts>
Ptr<T> Create (Ts&&... args)
{
return Ptr<T> (new T (std::forward<Ts> (args)...), false);
}
template <typename U>
U * PeekPointer (const Ptr<U> &p)
{
return p.m_ptr;
}
template <typename U>
U * GetPointer (const Ptr<U> &p)
{
p.Acquire ();
return p.m_ptr;
}
template <typename T>
std::ostream &operator << (std::ostream &os, const Ptr<T> &p)
{
os << PeekPointer (p);
return os;
}
template <typename T1, typename T2>
bool
operator == (Ptr<T1> const &lhs, T2 const *rhs)
{
return PeekPointer (lhs) == rhs;
}
template <typename T1, typename T2>
bool
operator == (T1 const *lhs, Ptr<T2> &rhs)
{
return lhs == PeekPointer (rhs);
}
template <typename T1, typename T2>
bool
operator != (Ptr<T1> const &lhs, T2 const *rhs)
{
return PeekPointer (lhs) != rhs;
}
template <typename T1, typename T2>
bool
operator != (T1 const *lhs, Ptr<T2> &rhs)
{
return lhs != PeekPointer (rhs);
}
template <typename T1, typename T2>
bool
operator == (Ptr<T1> const &lhs, Ptr<T2> const &rhs)
{
return PeekPointer (lhs) == PeekPointer (rhs);
}
template <typename T1, typename T2>
bool
operator != (Ptr<T1> const &lhs, Ptr<T2> const &rhs)
{
return PeekPointer (lhs) != PeekPointer (rhs);
}
template <typename T1, typename T2>
typename std::enable_if<std::is_same<T2, nullptr_t>::value, bool>::type
operator == (Ptr<T1> const &lhs, T2 nullPtr)
{
return PeekPointer (lhs) == nullptr;
}
template <typename T1, typename T2>
typename std::enable_if<std::is_same<T2, nullptr_t>::value, bool>::type
operator != (Ptr<T1> const &lhs, T2 nullPtr)
{
return PeekPointer (lhs) != nullptr;
}
template <typename T>
bool operator < (const Ptr<T> &lhs, const Ptr<T> &rhs)
{
return PeekPointer<T> (lhs) < PeekPointer<T> (rhs);
}
template <typename T>
bool
operator< (const Ptr<T> &lhs, const Ptr<const T> &rhs)
{
return PeekPointer<T> (lhs) < PeekPointer<const T> (rhs);
}
template <typename T>
bool
operator< (const Ptr<const T> &lhs, const Ptr<T> &rhs)
{
return PeekPointer<const T> (lhs) < PeekPointer<T> (rhs);
}
template <typename T>
bool
operator<= (const Ptr<T> &lhs, const Ptr<T> &rhs)
{
return PeekPointer<T> (lhs) <= PeekPointer<T> (rhs);
}
template <typename T>
bool operator > (const Ptr<T> &lhs, const Ptr<T> &rhs)
{
return PeekPointer<T> (lhs) > PeekPointer<T> (rhs);
}
template <typename T>
bool operator >= (const Ptr<T> &lhs, const Ptr<T> &rhs)
{
return PeekPointer<T> (lhs) >= PeekPointer<T> (rhs);
}
/**
* Cast a Ptr.
*
* \tparam T1 \deduced The desired type to cast to.
* \tparam T2 \deduced The type of the original Ptr.
* \param [in] p The original Ptr.
* \return The result of the cast.
*/
/** @{ */
template <typename T1, typename T2>
Ptr<T1>
ConstCast (Ptr<T2> const&p)
{
return Ptr<T1> (const_cast<T1 *> (PeekPointer (p)));
}
template <typename T1, typename T2>
Ptr<T1>
DynamicCast (Ptr<T2> const&p)
{
return Ptr<T1> (dynamic_cast<T1 *> (PeekPointer (p)));
}
template <typename T1, typename T2>
Ptr<T1>
StaticCast (Ptr<T2> const&p)
{
return Ptr<T1> (static_cast<T1 *> (PeekPointer (p)));
}
/** @} */
/**
* Return a deep copy of a Ptr.
*
* \tparam T \deduced The type of the underlying object.
* \param [in] object The object Ptr to copy.
* \returns The copy.
*/
/** @{ */
template <typename T>
Ptr<T> Copy (Ptr<T> object)
{
Ptr<T> p = Ptr<T> (new T (*PeekPointer (object)), false);
return p;
}
template <typename T>
Ptr<T> Copy (Ptr<const T> object)
{
Ptr<T> p = Ptr<T> (new T (*PeekPointer (object)), false);
return p;
}
/** @} */
/****************************************************
* Member method implementations.
***************************************************/
template <typename T>
void
Ptr<T>::Acquire (void) const
{
if (m_ptr != 0)
{
m_ptr->Ref ();
}
}
template <typename T>
Ptr<T>::Ptr ()
: m_ptr (0)
{}
template <typename T>
Ptr<T>::Ptr (T *ptr)
: m_ptr (ptr)
{
Acquire ();
}
template <typename T>
Ptr<T>::Ptr (T *ptr, bool ref)
: m_ptr (ptr)
{
if (ref)
{
Acquire ();
}
}
template <typename T>
Ptr<T>::Ptr (Ptr const&o)
: m_ptr (nullptr)
{
T* ptr = PeekPointer (o);
if (ptr != 0)
{
m_ptr = ptr;
Acquire ();
}
}
template <typename T>
template <typename U>
Ptr<T>::Ptr (Ptr<U> const &o)
: m_ptr (PeekPointer (o))
{
Acquire ();
}
template <typename T>
Ptr<T>::~Ptr ()
{
if (m_ptr != 0)
{
m_ptr->Unref ();
}
}
template <typename T>
Ptr<T> &
Ptr<T>::operator = (Ptr const& o)
{
if (&o == this)
{
return *this;
}
if (m_ptr != 0)
{
m_ptr->Unref ();
}
m_ptr = o.m_ptr;
Acquire ();
return *this;
}
template <typename T>
T *
Ptr<T>::operator -> ()
{
NS_ASSERT_MSG (m_ptr, "Attempted to dereference zero pointer");
return m_ptr;
}
template <typename T>
T *
Ptr<T>::operator -> () const
{
NS_ASSERT_MSG (m_ptr, "Attempted to dereference zero pointer");
return m_ptr;
}
template <typename T>
T &
Ptr<T>::operator * () const
{
NS_ASSERT_MSG (m_ptr, "Attempted to dereference zero pointer");
return *m_ptr;
}
template <typename T>
T &
Ptr<T>::operator * ()
{
NS_ASSERT_MSG (m_ptr, "Attempted to dereference zero pointer");
return *m_ptr;
}
template <typename T>
Ptr<T>::operator Tester * () const // NS_DEPRECATED_3_37
{
if (m_ptr == 0)
{
return 0;
}
static Tester test;
return &test;
}
template <typename T>
Ptr<T>::operator bool() const
{
return m_ptr != 0;
}
} // namespace ns3
/****************************************************
* Global Functions (outside namespace ns3)
***************************************************/
/**
* \ingroup ptr
* Hashing functor taking a `Ptr` and returning a @c std::size_t.
* For use with `unordered_map` and `unordered_set`.
*
* \note When a `Ptr` is used in a container the lifetime of the underlying
* object is at least as long as the container. In other words,
* you need to remove the object from the container when you are done with
* it, otherwise the object will persist until the container itself is
* deleted.
*
* \tparam T \deduced The type held by the `Ptr`
*/
template<class T>
struct
std::hash<ns3::Ptr<T>>
{
/**
* The functor.
* \param p The `Ptr` value to hash.
* \return the hash
*/
std::size_t
operator () (ns3::Ptr<T> p) const
{
return std::hash<const T *> () (ns3::PeekPointer (p));
}
};
#endif /* PTR_H */