unit-context.h

// Copyright (c) 2020-now by the Zeek Project. See LICENSE for details.
 
#pragma once
 
#include <cassert>
#include <string>
#include <utility>
 
#include <hilti/rt/exception.h>
#include <hilti/rt/type-info.h>
#include <hilti/rt/types/reference.h>
 
namespace spicy::rt {
 
HILTI_EXCEPTION(ContextMismatch, UsageError)
 
 
class UnitContext {
public:
    template<typename T>
    UnitContext(hilti::rt::StrongReference<T> obj, const hilti::rt::TypeInfo* ti)
        : _object(std::move(obj)), _type_info(ti) {}
    template<typename Context>
    hilti::rt::StrongReference<Context> as(const hilti::rt::TypeInfo* ti) const {
        if ( ti != _type_info )
            throw ContextMismatch(hilti::rt::fmt("context mismatch between related units: expected %s, but got %s",
                                                 _type_info->display,
                                                 ti->display));
 
        return hilti::rt::any_cast<hilti::rt::StrongReference<Context>>(_object);
    }
 
    UnitContext() = delete;
    UnitContext(const UnitContext&) = default;
    UnitContext(UnitContext&&) = default;
 
    UnitContext& operator=(const UnitContext&) = default;
    UnitContext& operator=(UnitContext&&) = default;
 
    virtual ~UnitContext(); // trigger vtable
 
private:
    hilti::rt::any _object;
    const hilti::rt::TypeInfo* _type_info;
};
 
namespace detail {
 
template<typename Context>
inline UnitContext createContext(Context ctx, const hilti::rt::TypeInfo* ti) {
    if ( ti->tag == hilti::rt::TypeInfo::Tag::StrongReference )
        ti = ti->strong_reference->valueType();
 
    return UnitContext(std::move(ctx), ti);
}
 
template<typename Context>
inline void setContext(hilti::rt::StrongReference<Context>& context,
                       const hilti::rt::TypeInfo* /*context_type*/,
                       const hilti::rt::Optional<UnitContext>& new_ctx,
                       const hilti::rt::TypeInfo* ti) {
    if ( new_ctx )
        context = new_ctx->as<Context>(ti);
    else
        context = nullptr;
}
 
} // namespace detail
 
} // namespace spicy::rt
 
namespace hilti::rt::detail::adl {
 
inline std::string to_string(const spicy::rt::UnitContext& /*ctx*/, rt::detail::adl::tag /*unused*/) {
    return "<unit context>";
}
 
} // namespace hilti::rt::detail::adl