mpd/src/client/Response.hxx

125 lines
3.4 KiB
C++

/*
* Copyright 2003-2021 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_RESPONSE_HXX
#define MPD_RESPONSE_HXX
#include "protocol/Ack.hxx"
#include <fmt/core.h>
#if FMT_VERSION < 70000 || FMT_VERSION >= 80000
#include <fmt/format.h>
#endif
#include <cstddef>
template<typename T> struct ConstBuffer;
class Client;
class TagMask;
class Response {
Client &client;
/**
* This command's index in the command list. Used to generate
* error messages.
*/
const unsigned list_index;
/**
* This command's name. Used to generate error messages.
*/
const char *command = "";
public:
Response(Client &_client, unsigned _list_index) noexcept
:client(_client), list_index(_list_index) {}
Response(const Response &) = delete;
Response &operator=(const Response &) = delete;
/**
* Returns a const reference to the associated #Client object.
* This should only be used to access a client's settings, to
* determine how to format the response. For this reason, the
* returned reference is "const".
*/
const Client &GetClient() const noexcept {
return client;
}
/**
* Accessor for Client::tag_mask. Can be used if caller wants
* to avoid including Client.hxx.
*/
[[gnu::pure]]
TagMask GetTagMask() const noexcept;
void SetCommand(const char *_command) noexcept {
command = _command;
}
bool Write(const void *data, size_t length) noexcept;
bool Write(const char *data) noexcept;
bool VFmt(fmt::string_view format_str, fmt::format_args args) noexcept;
template<typename S, typename... Args>
bool Fmt(const S &format_str, Args&&... args) noexcept {
#if FMT_VERSION >= 70000
return VFmt(fmt::to_string_view(format_str),
fmt::make_args_checked<Args...>(format_str,
args...));
#else
/* expensive fallback for older libfmt versions */
const auto result = fmt::format(format_str, args...);
return Write(result.data(), result.size());
#endif
}
/**
* Write a binary chunk; this writes the "binary" line, the
* given chunk and the trailing newline.
*
* @return true on success
*/
bool WriteBinary(ConstBuffer<void> payload) noexcept;
void Error(enum ack code, const char *msg) noexcept;
void VFmtError(enum ack code,
fmt::string_view format_str, fmt::format_args args) noexcept;
template<typename S, typename... Args>
void FmtError(enum ack code,
const S &format_str, Args&&... args) noexcept {
#if FMT_VERSION >= 70000
return VFmtError(code, fmt::to_string_view(format_str),
fmt::make_args_checked<Args...>(format_str,
args...));
#else
/* expensive fallback for older libfmt versions */
const auto result = fmt::format(format_str, args...);
return Error(code, result.c_str());
#endif
}
};
#endif