boost/log/attributes/attribute_set.hpp
/*
* Copyright Andrey Semashev 2007 - 2015.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*/
/*!
* \file attribute_set.hpp
* \author Andrey Semashev
* \date 08.03.2007
*
* This header contains definition of the attribute set container.
*/
#ifndef BOOST_LOG_ATTRIBUTE_SET_HPP_INCLUDED_
#define BOOST_LOG_ATTRIBUTE_SET_HPP_INCLUDED_
#include <cstddef>
#include <utility>
#include <iterator>
#include <boost/mpl/if.hpp>
#include <boost/move/core.hpp>
#include <boost/log/detail/config.hpp>
#include <boost/log/attributes/attribute_name.hpp>
#include <boost/log/attributes/attribute.hpp>
#include <boost/log/detail/header.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
BOOST_LOG_OPEN_NAMESPACE
class attribute_set;
class attribute_value_set;
namespace aux {
//! Reference proxy object to implement \c operator[]
class attribute_set_reference_proxy
{
private:
//! Key type
typedef attribute_name key_type;
//! Mapped attribute type
typedef attribute mapped_type;
private:
attribute_set* const m_pContainer;
const key_type m_key;
public:
//! Constructor
explicit attribute_set_reference_proxy(attribute_set* pContainer, key_type const& key) BOOST_NOEXCEPT :
m_pContainer(pContainer),
m_key(key)
{
}
//! Conversion operator (would be invoked in case of reading from the container)
BOOST_FORCEINLINE operator mapped_type() const BOOST_NOEXCEPT
{
return read_mapped_value();
}
//! Assignment operator (would be invoked in case of writing to the container)
mapped_type& operator= (mapped_type const& val) const;
private:
//! Reads the referenced mapped value from the container
mapped_type read_mapped_value() const BOOST_NOEXCEPT;
};
} // namespace aux
/*!
* \brief An attribute set class.
*
* An attribute set is an associative container with attribute name as a key and
* pointer to the attribute as a mapped value. The container allows storing only one element for each distinct
* key value. In most regards attribute set container provides interface similar to \c std::unordered_map.
* However, there are differences in \c operator[] semantics and a number of optimizations with regard to iteration.
* Besides, attribute names are stored as a read-only <tt>attribute_name</tt>'s instead of \c std::string,
* which saves memory and CPU time.
*/
class attribute_set
{
BOOST_COPYABLE_AND_MOVABLE_ALT(attribute_set)
friend class attribute_value_set;
friend class aux::attribute_set_reference_proxy;
public:
//! Key type
typedef attribute_name key_type;
//! Mapped attribute type
typedef attribute mapped_type;
//! Value type
typedef std::pair< const key_type, mapped_type > value_type;
//! Reference type
typedef value_type& reference;
//! Const reference type
typedef value_type const& const_reference;
//! Pointer type
typedef value_type* pointer;
//! Const pointer type
typedef value_type const* const_pointer;
//! Size type
typedef std::size_t size_type;
//! Difference type
typedef std::ptrdiff_t difference_type;
private:
//! \cond
//! Implementation
struct implementation;
friend struct implementation;
//! A base class for the container nodes
struct node_base
{
node_base* m_pPrev;
node_base* m_pNext;
node_base();
BOOST_DELETED_FUNCTION(node_base(node_base const&))
BOOST_DELETED_FUNCTION(node_base& operator= (node_base const&))
};
//! Container elements
struct node;
friend struct node;
struct node :
public node_base
{
value_type m_Value;
node(key_type const& key, mapped_type const& data);
};
//! Iterator class
#ifndef BOOST_LOG_NO_MEMBER_TEMPLATE_FRIENDS
template< bool fConstV > class iter;
template< bool fConstV > friend class iter;
#endif
template< bool fConstV >
class iter
{
friend class iter< !fConstV >;
friend class attribute_set;
public:
// Standard typedefs
typedef attribute_set::difference_type difference_type;
typedef attribute_set::value_type value_type;
typedef typename mpl::if_c<
fConstV,
attribute_set::const_reference,
attribute_set::reference
>::type reference;
typedef typename mpl::if_c<
fConstV,
attribute_set::const_pointer,
attribute_set::pointer
>::type pointer;
typedef std::bidirectional_iterator_tag iterator_category;
public:
// Constructors
BOOST_CONSTEXPR iter() : m_pNode(NULL) {}
explicit iter(node_base* pNode) BOOST_NOEXCEPT : m_pNode(pNode) {}
iter(iter< false > const& that) BOOST_NOEXCEPT : m_pNode(that.m_pNode) {}
//! Assignment
template< bool f >
iter& operator= (iter< f > const& that) BOOST_NOEXCEPT
{
m_pNode = that.m_pNode;
return *this;
}
// Comparison
template< bool f >
bool operator== (iter< f > const& that) const BOOST_NOEXCEPT { return (m_pNode == that.m_pNode); }
template< bool f >
bool operator!= (iter< f > const& that) const BOOST_NOEXCEPT { return (m_pNode != that.m_pNode); }
// Modification
iter& operator++ () BOOST_NOEXCEPT
{
m_pNode = m_pNode->m_pNext;
return *this;
}
iter& operator-- () BOOST_NOEXCEPT
{
m_pNode = m_pNode->m_pPrev;
return *this;
}
iter operator++ (int) BOOST_NOEXCEPT
{
iter tmp(*this);
m_pNode = m_pNode->m_pNext;
return tmp;
}
iter operator-- (int) BOOST_NOEXCEPT
{
iter tmp(*this);
m_pNode = m_pNode->m_pPrev;
return tmp;
}
// Dereferencing
pointer operator-> () const BOOST_NOEXCEPT { return &(static_cast< node* >(m_pNode)->m_Value); }
reference operator* () const BOOST_NOEXCEPT { return static_cast< node* >(m_pNode)->m_Value; }
node_base* base() const BOOST_NOEXCEPT { return m_pNode; }
private:
node_base* m_pNode;
};
//! \endcond
public:
#ifndef BOOST_LOG_DOXYGEN_PASS
//! Iterator type
typedef iter< false > iterator;
//! Const iterator type
typedef iter< true > const_iterator;
#else
/*!
* Iterator type. The iterator complies to the bidirectional iterator requirements.
*/
typedef implementation_defined iterator;
/*!
* Constant iterator type. The iterator complies to the bidirectional iterator requirements with read-only capabilities.
*/
typedef implementation_defined const_iterator;
#endif // BOOST_LOG_DOXYGEN_PASS
private:
//! Pointer to implementation
implementation* m_pImpl;
public:
/*!
* Default constructor.
*
* \post <tt>empty() == true</tt>
*/
BOOST_LOG_API attribute_set();
/*!
* Copy constructor.
*
* \post <tt>size() == that.size() && std::equal(begin(), end(), that.begin()) == true</tt>
*/
BOOST_LOG_API attribute_set(attribute_set const& that);
/*!
* Move constructor
*/
attribute_set(BOOST_RV_REF(attribute_set) that) BOOST_NOEXCEPT : m_pImpl(that.m_pImpl)
{
that.m_pImpl = NULL;
}
/*!
* Destructor. All stored references to attributes are released.
*/
BOOST_LOG_API ~attribute_set() BOOST_NOEXCEPT;
/*!
* Copy assignment operator.
*
* \post <tt>size() == that.size() && std::equal(begin(), end(), that.begin()) == true</tt>
*/
attribute_set& operator= (attribute_set that) BOOST_NOEXCEPT
{
this->swap(that);
return *this;
}
/*!
* Swaps two instances of the container.
*
* \b Throws: Nothing.
*/
void swap(attribute_set& that) BOOST_NOEXCEPT
{
implementation* const p = m_pImpl;
m_pImpl = that.m_pImpl;
that.m_pImpl = p;
}
/*!
* \return Iterator to the first element of the container.
*/
BOOST_LOG_API iterator begin() BOOST_NOEXCEPT;
/*!
* \return Iterator to the after-the-last element of the container.
*/
BOOST_LOG_API iterator end() BOOST_NOEXCEPT;
/*!
* \return Constant iterator to the first element of the container.
*/
BOOST_LOG_API const_iterator begin() const BOOST_NOEXCEPT;
/*!
* \return Constant iterator to the after-the-last element of the container.
*/
BOOST_LOG_API const_iterator end() const BOOST_NOEXCEPT;
/*!
* \return Number of elements in the container.
*/
BOOST_LOG_API size_type size() const BOOST_NOEXCEPT;
/*!
* \return true if there are no elements in the container, false otherwise.
*/
bool empty() const BOOST_NOEXCEPT { return (this->size() == 0); }
/*!
* The method finds the attribute by name.
*
* \param key Attribute name.
* \return Iterator to the found element or end() if the attribute with such name is not found.
*/
BOOST_LOG_API iterator find(key_type key) BOOST_NOEXCEPT;
/*!
* The method finds the attribute by name.
*
* \param key Attribute name.
* \return Iterator to the found element or \c end() if the attribute with such name is not found.
*/
const_iterator find(key_type key) const BOOST_NOEXCEPT
{
return const_iterator(const_cast< attribute_set* >(this)->find(key));
}
/*!
* The method counts the number of the attribute occurrences in the container. Since there can be only one
* attribute with a particular key, the method always return 0 or 1.
*
* \param key Attribute name.
* \return The number of times the attribute is found in the container.
*/
size_type count(key_type key) const BOOST_NOEXCEPT { return size_type(this->find(key) != this->end()); }
/*!
* Combined lookup/insertion operator. The operator semantics depends on the further usage of the returned reference.
* \li If the reference is used as an assignment target, the assignment expression is equivalent to element insertion,
* where the element is composed of the second argument of the \c operator[] as a key and the second argument of assignment
* as a mapped value.
* \li If the returned reference is used in context where a conversion to the mapped type is required,
* the result of the conversion is equivalent to the mapped value found with the second argument of the \c operator[] as a key,
* if such an element exists in the container, or a default-constructed mapped value, if an element does not exist in the
* container.
*
* \param key Attribute name.
* \return A smart reference object of unspecified type.
*/
aux::attribute_set_reference_proxy operator[] (key_type key) BOOST_NOEXCEPT
{
return aux::attribute_set_reference_proxy(this, key);
}
/*!
* Lookup operator
*
* \param key Attribute name.
* \return If an element with the corresponding attribute name is found in the container, its mapped value
* is returned. Otherwise a default-constructed mapped value is returned.
*/
mapped_type operator[] (key_type key) const BOOST_NOEXCEPT
{
const_iterator it = this->find(key);
if (it != end())
return it->second;
else
return mapped_type();
}
/*!
* Insertion method
*
* \param key Attribute name.
* \param data Pointer to the attribute. Must not be NULL.
* \returns A pair of values. If second is true, the insertion succeeded and the first component points to the
* inserted element. Otherwise the first component points to the element that prevents insertion.
*/
BOOST_LOG_API std::pair< iterator, bool > insert(key_type key, mapped_type const& data);
/*!
* Insertion method
*
* \param value An element to be inserted.
* \returns A pair of values. If second is true, the insertion succeeded and the first component points to the
* inserted element. Otherwise the first component points to the element that prevents insertion.
*/
std::pair< iterator, bool > insert(const_reference value)
{
return this->insert(value.first, value.second);
}
/*!
* Mass insertion method.
*
* \param begin A forward iterator that points to the first element to be inserted.
* \param end A forward iterator that points to the after-the-last element to be inserted.
*/
template< typename FwdIteratorT >
void insert(FwdIteratorT begin, FwdIteratorT end)
{
for (; begin != end; ++begin)
this->insert(*begin);
}
/*!
* Mass insertion method with ability to acquire iterators to the inserted elements.
*
* \param begin A forward iterator that points to the first element to be inserted.
* \param end A forward iterator that points to the after-the-last element to be inserted.
* \param out An output iterator that receives results of insertion of the elements
*/
template< typename FwdIteratorT, typename OutputIteratorT >
void insert(FwdIteratorT begin, FwdIteratorT end, OutputIteratorT out)
{
for (; begin != end; ++begin, ++out)
*out = this->insert(*begin);
}
/*!
* The method erases all attributes with the specified name
*
* \post All iterators to the erased elements become invalid.
* \param key Attribute name.
* \return Tne number of erased elements
*/
BOOST_LOG_API size_type erase(key_type key) BOOST_NOEXCEPT;
/*!
* The method erases the specified attribute
*
* \post All iterators to the erased element become invalid.
* \param it A valid iterator to the element to be erased.
* \return Tne number of erased elements
*/
BOOST_LOG_API void erase(iterator it) BOOST_NOEXCEPT;
/*!
* The method erases all attributes within the specified range
*
* \pre \a end is reachable from \a begin with a finite number of increments.
* \post All iterators to the erased elements become invalid.
* \param begin An iterator that points to the first element to be erased.
* \param end An iterator that points to the after-the-last element to be erased.
*/
BOOST_LOG_API void erase(iterator begin, iterator end) BOOST_NOEXCEPT;
/*!
* The method removes all elements from the container
*
* \post <tt>empty() == true</tt>
*/
BOOST_LOG_API void clear() BOOST_NOEXCEPT;
};
/*!
* Free swap overload
*/
inline void swap(attribute_set& left, attribute_set& right) BOOST_NOEXCEPT
{
left.swap(right);
}
namespace aux {
//! Reads the referenced mapped value from the container
inline attribute_set_reference_proxy::mapped_type attribute_set_reference_proxy::read_mapped_value() const BOOST_NOEXCEPT
{
attribute_set::iterator it = m_pContainer->find(m_key);
if (it != m_pContainer->end())
return it->second;
else
return mapped_type();
}
//! Assignment operator (would be invoked in case of writing to the container)
inline attribute_set_reference_proxy::mapped_type& attribute_set_reference_proxy::operator= (mapped_type const& val) const
{
std::pair< attribute_set::iterator, bool > res = m_pContainer->insert(m_key, val);
if (!res.second)
res.first->second = val;
return res.first->second;
}
} // namespace aux
#ifndef BOOST_LOG_DOXYGEN_PASS
inline attribute& attribute::operator= (aux::attribute_set_reference_proxy const& that) BOOST_NOEXCEPT
{
attribute attr = that;
this->swap(attr);
return *this;
}
#endif
BOOST_LOG_CLOSE_NAMESPACE // namespace log
} // namespace boost
#include <boost/log/detail/footer.hpp>
#endif // BOOST_LOG_ATTRIBUTE_SET_HPP_INCLUDED_