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MessageMatcher.hpp

//===-- rosa/core/MessageMatcher.hpp ----------------------------*- C++ -*-===//
//
// The RoSA Framework
//
//===----------------------------------------------------------------------===//
///
/// \file rosa/core/MessageMatcher.hpp
///
/// \author David Juhasz (david.juhasz@tuwien.ac.at)
///
/// \date 2017-2019
///
/// \brief Facilities for checking and matching types of values stored in
/// \c rosa::Message instances.
///
//===----------------------------------------------------------------------===//
#ifndef ROSA_CORE_MESSAGEMATCHER_HPP
#define ROSA_CORE_MESSAGEMATCHER_HPP
#include "rosa/core/Message.hpp"
#include <tuple>
namespace rosa {
/// Provides features to type-check a \c rosa::Message instance and extract
/// stored values from it into an \c std::tuple instance with matching type
/// arguments.
///
/// \tparam List \c rosa::TypeList to check the stored values against
template <typename List> struct MessageMatcher;
/// Definition of \c rosa::MessageMatcher for non-empty lists of types, like
/// \c rosa::Message itself.
///
/// \tparam Type first mandatory type
/// \tparam Types any further types
template <typename Type, typename... Types>
struct MessageMatcher<TypeList<Type, Types...>> {
/// \c rosa::Token associated to the given \c rosa::TypeList.
static constexpr Token T = TypeToken<Type, Types...>::Value;
/// Tells if the values stored in a \c rosa::Message instance are matching
/// types given as \c rosa::TypeList<T, Types...>, considering
/// \c rosa::AtomConstant instead of \c rosa::AtomValue.
///
/// \param Msg \c rosa::Message to match
///
/// \return whether the types of values stored in \p Msg matches
/// \c rosa::TypeList<Type, Types...>
static inline bool doesStronglyMatch(const Message &Msg) noexcept;
/// Gives a \c std::tuple with references to the values stored in a
/// type-matching instance of \c rosa::Message.
///
/// \param Msg \c rosa::Message to extract values from
///
/// \return \c std::tuple with references to the values stored in \p Msg
///
/// \pre Types of the values stored in \p Msg matches
/// \c rosa::TypeList<Type, Types...>:\code
/// doesStronglyMatch(Msg)
/// \endcode
static inline std::tuple<const Type &, const Types &...>
extractedValues(const Message &Msg) noexcept;
};
/// Turns a list of types into a \c rosa::TypeList for \c rosa::MessageMatcher.
template <typename Type, typename... Types>
using MsgMatcher = MessageMatcher<TypeList<Type, Types...>>;
/// Nested namespace with implementation for features of
/// \c rosa::MessageMatcher, consider it private.
namespace {
/// \defgroup MessageMatcherImpl Implementation for rosa::MessageMatcher
///
/// An implementation of type-checking and value extraction for
/// \c rosa::MessageMatcher.
///
///@{
/// Template declaration of \c MessageMatcherImpl.
///
/// \tparam List \c rosa::TypeList to match against
template <typename List> struct MessageMatcherImpl;
/// Specialization for \c rosa::EmptyTypeList.
template <> struct MessageMatcherImpl<EmptyTypeList> {
static bool doesStronglyMatchFrom(const Message &Msg,
const token_size_t Pos) noexcept {
// Matching EmptyTypeList only if reached the end of the stored types.
return Pos == Msg.Size;
}
static std::tuple<> extractedValuesFrom(const Message &Msg,
const token_size_t Pos) noexcept {
// It is valid to extract an empty list only if we reached the end of
// stored values.
ASSERT(doesStronglyMatchFrom(Msg, Pos));
return std::tie();
}
};
/// Specialization for \c rosa::AtomValue in the head.
template <AtomValue V, typename... Ts>
struct MessageMatcherImpl<TypeList<AtomConstant<V>, Ts...>> {
static bool doesHeadStronglyMatchAt(const Message &Msg,
const token_size_t Pos) noexcept {
// Matching a \c rosa::AtomConstant in the head if there is a type stored at
// \p Pos, the stored type is \c rosa::AtomValue, and the corresponding
// value matches the \c rosa::AtomValue \p V.
return Pos < Msg.Size && Msg.isTypeAt<AtomValue>(Pos) &&
Msg.valueAt<AtomValue>(Pos) == V;
}
static bool doesStronglyMatchFrom(const Message &Msg,
const token_size_t Pos) noexcept {
// Matching a non-empty list if the head is matching and the rest of the
// list is matching.
return doesHeadStronglyMatchAt(Msg, Pos) &&
MessageMatcherImpl<TypeList<Ts...>>::doesStronglyMatchFrom(Msg,
Pos + 1);
}
static std::tuple<const AtomConstant<V> &, const Ts &...>
extractedValuesFrom(const Message &Msg, const token_size_t Pos) noexcept {
// Extracting for a non-empty list with a matching \c rosa::AtomConstant in
// the head by getting the encoded \c rosa::AtomConstant and concatenating
// it with values extracted for the rest of the list.
ASSERT(doesHeadStronglyMatchAt(Msg, Pos));
return std::tuple_cat(
std::tie(AtomConstant<V>::Value),
MessageMatcherImpl<TypeList<Ts...>>::extractedValuesFrom(Msg, Pos + 1));
}
};
/// Definition for the general case when a regular built-in type (not a
/// \c rosa::AtomConstant) is in the head.
template <typename T, typename... Ts>
struct MessageMatcherImpl<TypeList<T, Ts...>> {
static bool doesHeadStronglyMatchAt(const Message &Msg,
const token_size_t Pos) noexcept {
// Matching the head if there is a type stored at \p Pos, and the stored
// type is \p T.
return Pos < Msg.Size && Msg.isTypeAt<T>(Pos);
}
static bool doesStronglyMatchFrom(const Message &Msg,
const token_size_t Pos) noexcept {
// Matching a non-empty list if the head is matching and the rest of the
// list is matching.
return doesHeadStronglyMatchAt(Msg, Pos) &&
MessageMatcherImpl<TypeList<Ts...>>::doesStronglyMatchFrom(Msg,
Pos + 1);
}
static std::tuple<const T &, const Ts &...>
extractedValuesFrom(const Message &Msg, const token_size_t Pos) noexcept {
// Extracting for a non-empty list with a matching head by getting the
// value for the head and concatenating it with values extracted for the
// rest of the list.
ASSERT(doesHeadStronglyMatchAt(Msg, Pos));
return std::tuple_cat(
std::tie(Msg.valueAt<T>(Pos)),
MessageMatcherImpl<TypeList<Ts...>>::extractedValuesFrom(Msg, Pos + 1));
}
};
///@}
} // End namespace
template <typename Type, typename... Types>
bool MessageMatcher<TypeList<Type, Types...>>::doesStronglyMatch(
const Message &Msg) noexcept {
// \note Fail quick on \c rosa::MessageMatcher::T, then match against list
// with squashed integers the way \c rosa::Token is generated.
return T == Msg.T &&
MessageMatcherImpl<typename SquashedTypeList<
TypeList<Type, Types...>>::Type>::doesStronglyMatchFrom(Msg, 0);
}
template <typename Type, typename... Types>
std::tuple<const Type &, const Types &...>
MessageMatcher<TypeList<Type, Types...>>::extractedValues(
const Message &Msg) noexcept {
ASSERT(doesStronglyMatch(Msg));
// \note Match against a list with squashed integers as \c rosa::Token is
// generated.
return MessageMatcherImpl<typename SquashedTypeList<
TypeList<Type, Types...>>::Type>::extractedValuesFrom(Msg, 0);
}
} // End namespace rosa
#endif // ROSA_CORE_MESSAGEMATCHER_HPP

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