expressions/formatters/char_decorator.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   formatters/char_decorator.hpp
 * \author Andrey Semashev
 * \date   17.11.2012
 *
 * The header contains implementation of a character decorator.
 */

#ifndef BOOST_LOG_EXPRESSIONS_FORMATTERS_CHAR_DECORATOR_HPP_INCLUDED_
#define BOOST_LOG_EXPRESSIONS_FORMATTERS_CHAR_DECORATOR_HPP_INCLUDED_

#include <vector>
#include <string>
#include <iterator>
#include <boost/assert.hpp>
#include <boost/static_assert.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/range/size.hpp>
#include <boost/range/const_iterator.hpp>
#include <boost/range/value_type.hpp>
#include <boost/move/core.hpp>
#include <boost/move/utility.hpp>
#include <boost/utility/addressof.hpp>
#include <boost/phoenix/core/actor.hpp>
#include <boost/phoenix/core/meta_grammar.hpp>
#include <boost/phoenix/core/terminal_fwd.hpp>
#include <boost/phoenix/core/is_nullary.hpp>
#include <boost/phoenix/core/environment.hpp>
#include <boost/phoenix/support/vector.hpp>
#include <boost/fusion/sequence/intrinsic/at_c.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/log/detail/config.hpp>
#include <boost/log/detail/custom_terminal_spec.hpp>
#include <boost/log/detail/deduce_char_type.hpp>
#include <boost/log/utility/formatting_ostream.hpp>
#include <boost/log/detail/header.hpp>

#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif

namespace boost {

BOOST_LOG_OPEN_NAMESPACE

namespace expressions {

namespace aux {

template< typename RangeT >
struct string_const_iterator : range_const_iterator< RangeT > {};
template< >
struct string_const_iterator< char* > { typedef char* type; };
template< >
struct string_const_iterator< const char* > { typedef const char* type; };
template< >
struct string_const_iterator< wchar_t* > { typedef wchar_t* type; };
template< >
struct string_const_iterator< const wchar_t* > { typedef const wchar_t* type; };

} // namespace aux

/*!
 * A simple character decorator implementation. This implementation replaces string patterns in the source string with
 * the fixed replacements. Source patterns and replacements can be specified at the object construction.
 */
template< typename CharT >
class pattern_replacer
{
public:
    //! Result type
    typedef void result_type;

    //! Character type
    typedef CharT char_type;
    //! String type
    typedef std::basic_string< char_type > string_type;

private:
    //! Lengths of source pattern and replacement
    struct string_lengths
    {
        unsigned int from_len, to_len;
    };

    //! List of the decorations to apply
    typedef std::vector< string_lengths > string_lengths_list;

private:
    //! Characters of the interleaved source patterns and replacements
    string_type m_decoration_chars;
    //! List of the decorations to apply
    string_lengths_list m_string_lengths;

public:
    /*!
     * Initializing constructor. Creates a pattern replacer with the specified \a decorations.
     * The provided decorations must be a sequence of \c std::pair of strings. The first element
     * of each pair is the source pattern, and the second one is the corresponding replacement.
     */
    template< typename RangeT >
    explicit pattern_replacer(RangeT const& decorations)
    {
        typedef typename range_const_iterator< RangeT >::type iterator;
        for (iterator it = begin(decorations), end_ = end(decorations); it != end_; ++it)
        {
            string_lengths lens;
            {
                typedef typename aux::string_const_iterator< typename range_value< RangeT >::type::first_type >::type first_iterator;
                first_iterator b = string_begin(it->first), e = string_end(it->first);
                lens.from_len = static_cast< unsigned int >(std::distance(b, e));
                m_decoration_chars.append(b, e);
            }
            {
                typedef typename aux::string_const_iterator< typename range_value< RangeT >::type::second_type >::type second_iterator;
                second_iterator b = string_begin(it->second), e = string_end(it->second);
                lens.to_len = static_cast< unsigned int >(std::distance(b, e));
                m_decoration_chars.append(b, e);
            }
            m_string_lengths.push_back(lens);
        }
    }
    /*!
     * Initializing constructor. Creates a pattern replacer with decorations specified
     * in form of two same-sized string sequences. Each <tt>i</tt>'th decoration will be
     * <tt>from[i]</tt> -> <tt>to[i]</tt>.
     */
    template< typename FromRangeT, typename ToRangeT >
    pattern_replacer(FromRangeT const& from, ToRangeT const& to)
    {
        typedef typename range_const_iterator< FromRangeT >::type iterator1;
        typedef typename range_const_iterator< ToRangeT >::type iterator2;
        iterator1 it1 = begin(from), end1 = end(from);
        iterator2 it2 = begin(to), end2 = end(to);
        for (; it1 != end1 && it2 != end2; ++it1, ++it2)
        {
            string_lengths lens;
            {
                typedef typename aux::string_const_iterator< typename range_value< FromRangeT >::type >::type from_iterator;
                from_iterator b = string_begin(*it1), e = string_end(*it1);
                lens.from_len = static_cast< unsigned int >(std::distance(b, e));
                m_decoration_chars.append(b, e);
            }
            {
                typedef typename aux::string_const_iterator< typename range_value< ToRangeT >::type >::type to_iterator;
                to_iterator b = string_begin(*it2), e = string_end(*it2);
                lens.to_len = static_cast< unsigned int >(std::distance(b, e));
                m_decoration_chars.append(b, e);
            }
            m_string_lengths.push_back(lens);
        }

        // Both sequences should be of the same size
        BOOST_ASSERT(it1 == end1);
        BOOST_ASSERT(it2 == end2);
    }
    //! Copy constructor
    pattern_replacer(pattern_replacer const& that) : m_decoration_chars(that.m_decoration_chars), m_string_lengths(that.m_string_lengths)
    {
    }

    //! Applies string replacements starting from the specified position
    result_type operator() (string_type& str, typename string_type::size_type start_pos = 0) const
    {
        typedef typename string_type::size_type size_type;

        const char_type* from_chars = m_decoration_chars.c_str();
        for (typename string_lengths_list::const_iterator it = m_string_lengths.begin(), end = m_string_lengths.end(); it != end; ++it)
        {
            const unsigned int from_len = it->from_len, to_len = it->to_len;
            const char_type* const to_chars = from_chars + from_len;
            for (size_type pos = str.find(from_chars, start_pos, from_len); pos != string_type::npos; pos = str.find(from_chars, pos, from_len))
            {
                str.replace(pos, from_len, to_chars, to_len);
                pos += to_len;
            }
            from_chars = to_chars + to_len;
        }
    }

private:
    static char_type* string_begin(char_type* p)
    {
        return p;
    }
    static const char_type* string_begin(const char_type* p)
    {
        return p;
    }
    template< typename RangeT >
    static typename range_const_iterator< RangeT >::type string_begin(RangeT const& r)
    {
        return begin(r);
    }

    static char_type* string_end(char_type* p)
    {
        while (*p)
            ++p;
        return p;
    }
    static const char_type* string_end(const char_type* p)
    {
        while (*p)
            ++p;
        return p;
    }
    template< typename RangeT >
    static typename range_const_iterator< RangeT >::type string_end(RangeT const& r)
    {
        return end(r);
    }
};

namespace aux {

//! Character decorator stream output terminal
template< typename LeftT, typename SubactorT, typename ImplT >
class char_decorator_output_terminal
{
private:
    //! Self type
    typedef char_decorator_output_terminal< LeftT, SubactorT, ImplT > this_type;

public:
    //! Internal typedef for type categorization
    typedef void _is_boost_log_terminal;

    //! Implementation type
    typedef ImplT impl_type;

    //! Character type
    typedef typename impl_type::char_type char_type;
    //! String type
    typedef typename impl_type::string_type string_type;
    //! Adopted actor type
    typedef SubactorT subactor_type;

    //! Result type definition
    template< typename >
    struct result;

    template< typename ThisT, typename ContextT >
    struct result< ThisT(ContextT) >
    {
        typedef typename remove_cv< typename remove_reference< ContextT >::type >::type context_type;
        typedef typename phoenix::evaluator::impl<
            typename LeftT::proto_base_expr&,
            context_type,
            phoenix::unused
        >::result_type type;
    };

private:
    //! Left argument actor
    LeftT m_left;
    //! Adopted formatter actor
    subactor_type m_subactor;
    //! Implementation type
    impl_type m_impl;

public:
    /*!
     * Initializing constructor. Creates decorator of the \a fmt formatter with the specified \a decorations.
     */
    char_decorator_output_terminal(LeftT const& left, subactor_type const& sub, impl_type const& impl) :
        m_left(left), m_subactor(sub), m_impl(impl)
    {
    }
    /*!
     * Copy constructor
     */
    char_decorator_output_terminal(char_decorator_output_terminal const& that) :
        m_left(that.m_left), m_subactor(that.m_subactor), m_impl(that.m_impl)
    {
    }

    /*!
     * Invokation operator
     */
    template< typename ContextT >
    typename result< this_type(ContextT const&) >::type operator() (ContextT const& ctx)
    {
        // Flush the stream and keep the current write position in the target string
        typedef typename result< this_type(ContextT const&) >::type result_type;
        result_type strm = phoenix::eval(m_left, ctx);
        strm.flush();
        typename string_type::size_type const start_pos = strm.rdbuf()->storage()->size();

        // Invoke the adopted formatter
        typedef typename result< this_type(ContextT const&) >::type result_type;
        phoenix::eval(m_subactor, ctx);

        // Flush the buffered characters and apply decorations
        strm.flush();
        m_impl(*strm.rdbuf()->storage(), start_pos);

        return strm;
    }

    /*!
     * Invokation operator
     */
    template< typename ContextT >
    typename result< const this_type(ContextT const&) >::type operator() (ContextT const& ctx) const
    {
        // Flush the stream and keep the current write position in the target string
        typedef typename result< const this_type(ContextT const&) >::type result_type;
        result_type strm = phoenix::eval(m_left, ctx);
        strm.flush();
        typename string_type::size_type const start_pos = strm.rdbuf()->storage()->size();

        // Invoke the adopted formatter
        typedef typename result< const this_type(ContextT const&) >::type result_type;
        phoenix::eval(m_subactor, ctx);

        // Flush the buffered characters and apply decorations
        strm.flush();
        m_impl(*strm.rdbuf()->storage(), start_pos);

        return strm;
    }

    BOOST_DELETED_FUNCTION(char_decorator_output_terminal())
};

} // namespace aux

/*!
 * Character decorator terminal class. This formatter allows to modify strings generated by other
 * formatters on character level. The most obvious application of decorators is replacing
 * a certain set of characters with decorated equivalents to satisfy requirements of
 * text-based sinks.
 *
 * The \c char_decorator_terminal class aggregates the formatter being decorated, and a set
 * of string pairs that are used as decorations. All decorations are applied sequentially.
 * The \c char_decorator_terminal class is a formatter itself, so it can be used to construct
 * more complex formatters, including nesting decorators.
 */
template< typename SubactorT, typename ImplT >
class char_decorator_terminal
{
private:
    //! Self type
    typedef char_decorator_terminal< SubactorT, ImplT > this_type;

public:
    //! Internal typedef for type categorization
    typedef void _is_boost_log_terminal;

    //! Implementation type
    typedef ImplT impl_type;
    //! Character type
    typedef typename impl_type::char_type char_type;
    //! String type
    typedef typename impl_type::string_type string_type;
    //! Stream type
    typedef basic_formatting_ostream< char_type > stream_type;
    //! Adopted actor type
    typedef SubactorT subactor_type;

    //! Result type definition
    typedef string_type result_type;

private:
    //! Adopted formatter actor
    subactor_type m_subactor;
    //! Implementation
    impl_type m_impl;

public:
    /*!
     * Initializing constructor.
     */
    char_decorator_terminal(subactor_type const& sub, impl_type const& impl) : m_subactor(sub), m_impl(impl)
    {
    }
    /*!
     * Copy constructor
     */
    char_decorator_terminal(char_decorator_terminal const& that) : m_subactor(that.m_subactor), m_impl(that.m_impl)
    {
    }

    /*!
     * \returns Adopted subactor
     */
    subactor_type const& get_subactor() const
    {
        return m_subactor;
    }

    /*!
     * \returns Implementation
     */
    impl_type const& get_impl() const
    {
        return m_impl;
    }

    /*!
     * Invokation operator
     */
    template< typename ContextT >
    result_type operator() (ContextT const& ctx)
    {
        string_type str;
        stream_type strm(str);

        // Invoke the adopted formatter
        typedef phoenix::vector3<
            subactor_type*,
            typename fusion::result_of::at_c<
                typename remove_cv<
                    typename remove_reference<
                        typename phoenix::result_of::env< ContextT const& >::type
                    >::type
                >::type::args_type,
                0
            >::type,
            stream_type&
        > env_type;
        env_type env = { boost::addressof(m_subactor), fusion::at_c< 0 >(phoenix::env(ctx).args()), strm };
        phoenix::eval(m_subactor, phoenix::make_context(env, phoenix::actions(ctx)));

        // Flush the buffered characters and apply decorations
        strm.flush();
        m_impl(*strm.rdbuf()->storage());

        return boost::move(str);
    }

    /*!
     * Invokation operator
     */
    template< typename ContextT >
    result_type operator() (ContextT const& ctx) const
    {
        string_type str;
        stream_type strm(str);

        // Invoke the adopted formatter
        typedef phoenix::vector3<
            const subactor_type*,
            typename fusion::result_of::at_c<
                typename remove_cv<
                    typename remove_reference<
                        typename phoenix::result_of::env< ContextT const& >::type
                    >::type
                >::type::args_type,
                0
            >::type,
            stream_type&
        > env_type;
        env_type env = { boost::addressof(m_subactor), fusion::at_c< 0 >(phoenix::env(ctx).args()), strm };
        phoenix::eval(m_subactor, phoenix::make_context(env, phoenix::actions(ctx)));

        // Flush the buffered characters and apply decorations
        strm.flush();
        m_impl(*strm.rdbuf()->storage());

        return boost::move(str);
    }

    BOOST_DELETED_FUNCTION(char_decorator_terminal())
};

/*!
 * Character decorator actor
 */
template< typename SubactorT, typename ImplT, template< typename > class ActorT = phoenix::actor >
class char_decorator_actor :
    public ActorT< char_decorator_terminal< SubactorT, ImplT > >
{
public:
    //! Base terminal type
    typedef char_decorator_terminal< SubactorT, ImplT > terminal_type;
    //! Character type
    typedef typename terminal_type::char_type char_type;

    //! Base actor type
    typedef ActorT< terminal_type > base_type;

public:
    //! Initializing constructor
    explicit char_decorator_actor(base_type const& act) : base_type(act)
    {
    }

    //! Returns reference to the terminal
    terminal_type const& get_terminal() const
    {
        return this->proto_expr_.child0;
    }
};

#ifndef BOOST_LOG_DOXYGEN_PASS

#define BOOST_LOG_AUX_OVERLOAD(left_ref, right_ref)\
    template< typename LeftExprT, typename SubactorT, typename ImplT, template< typename > class ActorT >\
    BOOST_FORCEINLINE phoenix::actor< aux::char_decorator_output_terminal< phoenix::actor< LeftExprT >, SubactorT, ImplT > >\
    operator<< (phoenix::actor< LeftExprT > left_ref left, char_decorator_actor< SubactorT, ImplT, ActorT > right_ref right)\
    {\
        typedef aux::char_decorator_output_terminal< phoenix::actor< LeftExprT >, SubactorT, ImplT > terminal_type;\
        phoenix::actor< terminal_type > actor = {{ terminal_type(left, right.get_terminal().get_subactor(), right.get_terminal().get_impl()) }};\
        return actor;\
    }

#include <boost/log/detail/generate_overloads.hpp>

#undef BOOST_LOG_AUX_OVERLOAD

#endif // BOOST_LOG_DOXYGEN_PASS

namespace aux {

template< typename RangeT >
class char_decorator_gen1
{
    RangeT const& m_decorations;

    typedef typename boost::log::aux::deduce_char_type< typename range_value< RangeT >::type::first_type >::type char_type;

public:
    explicit char_decorator_gen1(RangeT const& decorations) : m_decorations(decorations)
    {
    }

    template< typename SubactorT >
    BOOST_FORCEINLINE char_decorator_actor< SubactorT, pattern_replacer< char_type > > operator[] (SubactorT const& subactor) const
    {
        typedef pattern_replacer< char_type > replacer_type;
        typedef char_decorator_actor< SubactorT, replacer_type > result_type;
        typedef typename result_type::terminal_type terminal_type;
        typename result_type::base_type act = {{ terminal_type(subactor, replacer_type(m_decorations)) }};
        return result_type(act);
    }
};

template< typename FromRangeT, typename ToRangeT >
class char_decorator_gen2
{
    FromRangeT const& m_from;
    ToRangeT const& m_to;

    typedef typename boost::log::aux::deduce_char_type< typename range_value< FromRangeT >::type >::type from_char_type;
    typedef typename boost::log::aux::deduce_char_type< typename range_value< ToRangeT >::type >::type to_char_type;
    BOOST_STATIC_ASSERT_MSG((is_same< from_char_type, to_char_type >::value), "Boost.Log: character decorator cannot be instantiated with different character types for source and replacement strings");

public:
    char_decorator_gen2(FromRangeT const& from, ToRangeT const& to) : m_from(from), m_to(to)
    {
    }

    template< typename SubactorT >
    BOOST_FORCEINLINE char_decorator_actor< SubactorT, pattern_replacer< from_char_type > > operator[] (SubactorT const& subactor) const
    {
        typedef pattern_replacer< from_char_type > replacer_type;
        typedef char_decorator_actor< SubactorT, replacer_type > result_type;
        typedef typename result_type::terminal_type terminal_type;
        typename result_type::base_type act = {{ terminal_type(subactor, replacer_type(m_from, m_to)) }};
        return result_type(act);
    }
};

} // namespace aux

/*!
 * The function returns a decorator generator object. The generator provides <tt>operator[]</tt> that can be used
 * to construct the actual decorator.
 *
 * \param decorations A sequence of string pairs that will be used as decorations. Every <tt>decorations[i].first</tt>
 *                    substring occurrence in the output will be replaced with <tt>decorations[i].second</tt>.
 */
template< typename RangeT >
BOOST_FORCEINLINE aux::char_decorator_gen1< RangeT > char_decor(RangeT const& decorations)
{
    return aux::char_decorator_gen1< RangeT >(decorations);
}

/*!
 * The function returns a decorator generator object. The generator provides <tt>operator[]</tt> that can be used
 * to construct the actual decorator.
 *
 * \param from A sequence of strings that will be sought in the output.
 * \param to A sequence of strings that will be used as replacements.
 *
 * \note The \a from and \a to sequences mush be of the same size. Every <tt>from[i]</tt>
 *       substring occurrence in the output will be replaced with <tt>to[i]</tt>.
 */
template< typename FromRangeT, typename ToRangeT >
BOOST_FORCEINLINE aux::char_decorator_gen2< FromRangeT, ToRangeT > char_decor(FromRangeT const& from, ToRangeT const& to)
{
    return aux::char_decorator_gen2< FromRangeT, ToRangeT >(from, to);
}

} // namespace expressions

BOOST_LOG_CLOSE_NAMESPACE // namespace log

#ifndef BOOST_LOG_DOXYGEN_PASS

namespace phoenix {

namespace result_of {

template< typename SubactorT, typename ImplT >
struct is_nullary< custom_terminal< boost::log::expressions::char_decorator_terminal< SubactorT, ImplT > > > :
    public mpl::false_
{
};

template< typename LeftT, typename SubactorT, typename ImplT >
struct is_nullary< custom_terminal< boost::log::expressions::aux::char_decorator_output_terminal< LeftT, SubactorT, ImplT > > > :
    public mpl::false_
{
};

} // namespace result_of

} // namespace phoenix

#endif

} // namespace boost

#include <boost/log/detail/footer.hpp>

#endif // BOOST_LOG_EXPRESSIONS_FORMATTERS_CHAR_DECORATOR_HPP_INCLUDED_