construct/include/ircd/spirit.h

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.

#ifndef HAVE_IRCD_SPIRIT_H
#define HAVE_IRCD_SPIRIT_H

/// This file is not part of the IRCd standard include list (stdinc.h) because
/// it involves extremely expensive boost headers for creating formal spirit
/// grammars. Include this in a definition file which defines such grammars.
///
/// Note that directly sharing elements of a grammar between two compilation
/// units can be achieved with forward declarations in `ircd/grammar.h`.

// ircd.h is included here so that it can be compiled into this header. Then
// this becomes the single leading precompiled header.
#include <ircd/ircd.h>

// Disables asserts in spirit headers even when we're NDEBUG due to
// some false asserts around boolean character tests in spirit.
#define BOOST_DISABLE_ASSERTS

#pragma GCC visibility push(default)
#include <boost/config.hpp>
#include <boost/function.hpp>
#pragma GCC visibility pop

#pragma GCC visibility push(hidden)
#include <boost/fusion/sequence.hpp>
#include <boost/fusion/iterator.hpp>
#include <boost/fusion/adapted.hpp>
#include <boost/fusion/functional.hpp>
#include <boost/fusion/algorithm.hpp>
#include <boost/fusion/include/std_pair.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/karma.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/spirit/repository/include/qi_seek.hpp>
#include <boost/spirit/repository/include/qi_subrule.hpp>
#pragma GCC visibility pop

namespace ircd {
namespace spirit
__attribute__((visibility("default")))
{
	struct substring_view;
	template<class parent_error> struct expectation_failure;

	extern thread_local char rulebuf[64]; // parse.cc
}}

namespace ircd
__attribute__((visibility("default")))
{
	template<class parent_error,
	         class it = const char *,
	         class... args>
	bool parse(args&&...);

	template<class gen,
	         class... attr>
	bool generate(mutable_buffer &out, gen&&, attr&&...);

	template<class gen>
	bool generate(mutable_buffer &out, gen&&);
}

namespace ircd {
namespace spirit
__attribute__((visibility("hidden")))
{
	namespace spirit = boost::spirit;
	namespace ascii = spirit::ascii;
	namespace karma = spirit::karma;
	namespace qi = spirit::qi;
	namespace phx = boost::phoenix;

	using _val_type = phx::actor<spirit::attribute<0>>;
	using _r0_type = phx::actor<spirit::attribute<0>>;
	using _r1_type = phx::actor<spirit::attribute<1>>;
	using _r2_type = phx::actor<spirit::attribute<2>>;
	using _r3_type = phx::actor<spirit::attribute<3>>;

	using spirit::unused_type;
	using spirit::auto_;
	using spirit::_pass;
	using spirit::_val;

	using qi::locals;
	using qi::_a;
	using qi::_a_type;
	using qi::_r1_type;
	using qi::raw;
	using qi::omit;
	using qi::matches;
	using qi::hold;
	using qi::eoi;
	using qi::eps;
	using qi::expect;
	using qi::attr;
	using qi::attr_cast;
	using qi::repeat;
	using qi::lit;
	using qi::char_;
	using qi::byte_;
	using qi::string;
	using qi::short_;
	using qi::ushort_;
	using qi::word;
	using qi::big_word;
	using qi::little_word;
	using qi::int_;
	using qi::uint_;
	using qi::dword;
	using qi::big_dword;
	using qi::little_dword;
	using qi::long_;
	using qi::ulong_;
	using qi::qword;
	using qi::big_qword;
	using qi::little_qword;
	using qi::float_;
	using qi::bin_float;
	using qi::big_bin_float;
	using qi::little_bin_float;
	using qi::double_;
	using qi::bin_double;
	using qi::big_bin_double;
	using qi::little_bin_double;
	using spirit::repository::qi::seek;

	using karma::lit;
	using karma::char_;
	using karma::long_;
	using karma::double_;
	using karma::bool_;
	using karma::eps;
	using karma::attr_cast;
	using karma::maxwidth;
	using karma::buffer;
	using karma::skip;

	using prop_mask = mpl_::int_
	<
		karma::generator_properties::no_properties
		| karma::generator_properties::buffering
		| karma::generator_properties::counting
		| karma::generator_properties::tracking
		| karma::generator_properties::disabling
	>;
	using sink_type = karma::detail::output_iterator<char *, prop_mask, unused_type>;

	template<size_t idx,
	         class semantic_context>
	auto &
	attr_at(semantic_context&&);

	template<size_t idx,
	         class semantic_context>
	auto &
	local_at(semantic_context&&);
}}

namespace ircd::spirit::local
{
	using qi::_0;
	using qi::_1;
	using qi::_2;
	using qi::_3;
}

namespace ircd {
namespace spirit
__attribute__((visibility("default")))
{
	extern thread_local mutable_buffer *sink_buffer;
}}

struct ircd::spirit::substring_view
:ircd::string_view
{
	using _iterator = boost::spirit::karma::detail::indirect_iterator<const char *>;
	using _iterator_range = boost::iterator_range<_iterator>;

	using ircd::string_view::string_view;
	explicit substring_view(const _iterator_range &range)
	:ircd::string_view
	{
		std::addressof(*range.begin()), std::addressof(*range.end())
	}
	{}
};

template<class parent_error>
struct __attribute__((visibility("default")))
ircd::spirit::expectation_failure
:parent_error
{
	template<class it = const char *>
	expectation_failure(const qi::expectation_failure<it> &e,
	                    const ssize_t &show_max = 64);

	template<class it = const char *>
	expectation_failure(const qi::expectation_failure<it> &e,
	                    const it &start,
	                    const ssize_t &show_max = 64);
};

template<class parent>
template<class it>
ircd::spirit::expectation_failure<parent>::expectation_failure(const qi::expectation_failure<it> &e,
		                                                       const ssize_t &show_max)
:parent
{
	"Expected %s. You input %zd invalid characters :%s",
	ircd::string(rulebuf, e.what_),
	std::distance(e.first, e.last),
	string_view{e.first, e.first + std::min(std::distance(e.first, e.last), show_max)}
}
{}

template<class parent>
template<class it>
ircd::spirit::expectation_failure<parent>::expectation_failure(const qi::expectation_failure<it> &e,
                                                               const it &start,
		                                                       const ssize_t &show_max)
:parent
{
	"Expected %s. You input %zd invalid characters somewhere between position %zd and %zd: %s",
	ircd::string(rulebuf, e.what_),
	std::distance(e.first, e.last),
	std::distance(start, e.first),
	std::distance(start, e.last),
	string_view{e.first, e.first + std::min(std::distance(e.first, e.last), show_max)}
}
{}

template<class gen>
inline bool
ircd::generate(mutable_buffer &out,
               gen&& g)
{
	using namespace ircd::spirit;

	assert(!sink_buffer);
	const scope_restore _sink_buffer
	{
		sink_buffer, &out
	};

	sink_type sink
	{
		begin(out)
	};

	const auto gg
	{
		karma::maxwidth(size(out))[std::forward<gen>(g)]
	};

	const auto ret
	{
		karma::generate(sink, gg)
	};

	return ret;
}

template<class gen,
         class... attr>
inline bool
ircd::generate(mutable_buffer &out,
               gen&& g,
               attr&&... a)
{
	using namespace ircd::spirit;

	assert(!sink_buffer);
	const scope_restore _sink_buffer
	{
		sink_buffer, &out
	};

	sink_type sink
	{
		begin(out)
	};

	const auto gg
	{
		karma::maxwidth(size(out))[std::forward<gen>(g)]
	};

	const auto ret
	{
		karma::generate(sink, gg, std::forward<attr>(a)...)
	};

	return ret;
}

template<class parent_error,
         class it,
         class... args>
inline bool
ircd::parse(args&&... a)
try
{
	return spirit::qi::parse(std::forward<args>(a)...);
}
catch(const spirit::qi::expectation_failure<it> &e)
{
	throw spirit::expectation_failure<parent_error>(e);
}

template<size_t idx,
         class semantic_context>
auto &
ircd::spirit::local_at(semantic_context&& c)
{
	return boost::fusion::at_c<idx>(c.locals);
}

template<size_t idx,
         class semantic_context>
auto &
ircd::spirit::attr_at(semantic_context&& c)
{
	return boost::fusion::at_c<idx>(c.attributes);
}

template<>
[[gnu::visibility("internal")]]
inline bool
boost::spirit::karma::detail::buffer_sink::copy(ircd::spirit::sink_type &sink,
                                                size_t maxwidth)
const
{
	assert(ircd::spirit::sink_buffer);
	return true;
}

template<>
[[gnu::visibility("internal")]]
inline bool
boost::spirit::karma::detail::buffer_sink::copy_rest(ircd::spirit::sink_type &sink,
                                                     size_t start_at)
const
{
	assert(ircd::spirit::sink_buffer);
	assert(false);
	return true;
}

template<>
[[gnu::visibility("internal")]]
inline void
boost::spirit::karma::detail::buffer_sink::output(const char &value)
{
	assert(ircd::spirit::sink_buffer);
	auto &buf(*ircd::spirit::sink_buffer);
	ircd::consume(buf, ircd::copy(buf, value));
}

#endif // HAVE_IRCD_SPIRIT_H