error_helper.h

/*
 * SPDX-FileCopyrightText: 2013 Barefoot Networks, Inc.
 * Copyright 2013-present Barefoot Networks, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#ifndef LIB_ERROR_HELPER_H_
#define LIB_ERROR_HELPER_H_
 
#include <type_traits>
 
#include <boost/format.hpp>
 
#include "lib/error_message.h"
#include "lib/source_file.h"
#include "lib/stringify.h"
 
namespace P4 {
namespace priv {
 
// All these methods return std::string because this is the native format of boost::format
// Position is printed at the beginning.
static inline ErrorMessage error_helper(boost::format &f, ErrorMessage out) {
    out.message = boost::str(f);
    return out;
}
 
template <class... Args>
auto error_helper(boost::format &f, ErrorMessage out, const char *t, Args &&...args) {
    return error_helper(f % t, out, std::forward<Args>(args)...);
}
 
template <typename T, class... Args>
auto error_helper(boost::format &f, ErrorMessage out, const T &t,
                  Args &&...args) -> std::enable_if_t<Util::has_toString_v<T>, ErrorMessage>;
 
template <typename T, class... Args>
auto error_helper(boost::format &f, ErrorMessage out, const T &t, Args &&...args)
    -> std::enable_if_t<!Util::has_toString_v<T> && !std::is_pointer_v<T>, ErrorMessage>;
 
template <typename T, class... Args>
auto error_helper(boost::format &f, ErrorMessage out, const T *t, Args &&...args) {
    // Contrary to bug_helper we do not want to show raw pointers to users in
    // ordinary error messages. Therefore we explicitly delegate to
    // reference-arg implementation here.
    return error_helper(f, out, *t, std::forward<Args>(args)...);
}
 
template <class... Args>
ErrorMessage error_helper(boost::format &f, ErrorMessage out, const Util::SourceInfo &info,
                          Args &&...args) {
    if (info.isValid()) out.locations.push_back(info);
    return error_helper(f % "", std::move(out), std::forward<Args>(args)...);
}
 
template <typename T>
void maybeAddSourceInfo(ErrorMessage &out, const T &t) {
    if constexpr (Util::has_SourceInfo_v<T>) {
        auto info = t.getSourceInfo();
        if (info.isValid()) out.locations.push_back(info);
    }
}
 
template <typename T, class... Args>
auto error_helper(boost::format &f, ErrorMessage out, const T &t, Args &&...args)
    -> std::enable_if_t<!Util::has_toString_v<T> && !std::is_pointer_v<T>, ErrorMessage> {
    maybeAddSourceInfo(out, t);
    return error_helper(f % t, std::move(out), std::forward<Args>(args)...);
}
 
template <typename T, class... Args>
auto error_helper(boost::format &f, ErrorMessage out, const T &t,
                  Args &&...args) -> std::enable_if_t<Util::has_toString_v<T>, ErrorMessage> {
    maybeAddSourceInfo(out, t);
    return error_helper(f % t.toString(), std::move(out), std::forward<Args>(args)...);
}
 
}  // namespace priv
 
// Most direct invocations of error_helper usually only reduce arguments
template <class... Args>
ErrorMessage error_helper(boost::format &f, Args &&...args) {
    ErrorMessage msg;
    return priv::error_helper(f, msg, std::forward<Args>(args)...);
}
 
// Invoked from ErrorReporter
template <class... Args>
ErrorMessage error_helper(boost::format &f, ErrorMessage msg, Args &&...args) {
    return priv::error_helper(f, std::move(msg), std::forward<Args>(args)...);
}
 
// This overload exists for backwards compatibility
template <class... Args>
ErrorMessage error_helper(boost::format &f, const std::string &prefix, const Util::SourceInfo &info,
                          const std::string &suffix, Args &&...args) {
    return priv::error_helper(f, ErrorMessage(prefix, info, suffix), std::forward<Args>(args)...);
}
 
}  // namespace P4
 
#endif /* LIB_ERROR_HELPER_H_ */