// Copyright (c) 2023, The Monero Project
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#pragma once
#include <boost/utility/string_ref.hpp>
#include <boost/range/size.hpp>
#include <cstdint>
#include <system_error>
#include <type_traits>
#include "byte_slice.h"
#include "serialization/wire/error.h"
#include "serialization/wire/field.h"
#include "serialization/wire/traits.h"
#include "span.h"
/*
Custom types (e.g type `type` in namespace `ns`) can define an output function by:
* `namespace wire { template<> struct is_array<ns::type> : std::true_type {}; }`
* `namespace wire { template<> struct is_blob<ns::type> : std::true_type {}; }`
* `namespace wire { void write_bytes(writer&, const ns::type&); }`
* `namespace ns { void write_bytes(wire::writer&, const type&); }`
See `wrappers.h` for `is_array` requirements, and `traits.h` for `is_blob`
requirements. `write_bytes` function can also specify derived type for faster
output (i.e. `namespace ns { void write_bytes(wire::epee_writer&, type&); }`).
Using the derived type allows the compiler to de-virtualize and allows for
custom functions not defined by base interface. Using base interface allows
for multiple formats with minimal instruction count. */
namespace wire
{
//! Interface for converting C/C++ objects to "wire" (byte) formats.
struct writer
{
writer() = default;
virtual ~writer() noexcept;
//! By default, insist on retrieving array size before writing array
static constexpr std::true_type need_array_size() noexcept { return{}; }
virtual void boolean(bool) = 0;
virtual void integer(std::intmax_t) = 0;
virtual void unsigned_integer(std::uintmax_t) = 0;
virtual void real(double) = 0;
virtual void string(boost::string_ref) = 0;
virtual void binary(epee::span<const std::uint8_t>) = 0;
virtual void start_array(std::size_t) = 0;
virtual void end_array() = 0;
virtual void start_object(std::size_t) = 0;
virtual void key(boost::string_ref) = 0;
virtual void binary_key(epee::span<const std::uint8_t>) = 0;
virtual void end_object() = 0;
protected:
writer(const writer&) = default;
writer(writer&&) = default;
writer& operator=(const writer&) = default;
writer& operator=(writer&&) = default;
};
template<typename W>
inline void write_arithmetic(W& dest, const bool source)
{ dest.boolean(source); }
template<typename W>
inline void write_arithmetic(W& dest, const int source)
{ dest.integer(source); }
template<typename W>
inline void write_arithmetic(W& dest, const long source)
{ dest.integer(std::intmax_t(source)); }
template<typename W>
inline void write_arithmetic(W& dest, const long long source)
{ dest.integer(std::intmax_t(source)); }
template<typename W>
inline void write_arithmetic(W& dest, const unsigned source)
{ dest.unsigned_integer(source); }
template<typename W>
inline void write_arithmetic(W& dest, const unsigned long source)
{ dest.unsigned_integer(std::uintmax_t(source)); }
template<typename W>
inline void write_arithmetic(W& dest, const unsigned long long source)
{ dest.unsigned_integer(std::uintmax_t(source));}
template<typename W>
inline void write_arithmetic(W& dest, const double source)
{ dest.real(source); }
// Template both arguments to allow derived writer specializations
template<typename W, typename T>
inline std::enable_if_t<std::is_arithmetic<T>::value> write_bytes(W& dest, const T source)
{ write_arithmetic(dest, source); }
template<typename W>
inline void write_bytes(W& dest, const boost::string_ref source)
{ dest.string(source); }
template<typename W, typename T>
inline std::enable_if_t<is_blob<T>::value> write_bytes(W& dest, const T& source)
{ dest.binary(epee::as_byte_span(source)); }
template<typename W>
inline void write_bytes(W& dest, const epee::span<const std::uint8_t> source)
{ dest.binary(source); }
template<typename W>
inline void write_bytes(W& dest, const epee::byte_slice& source)
{ write_bytes(dest, epee::to_span(source)); }
//! Use `write_bytes(...)` method if available for `T`.
template<typename W, typename T>
inline auto write_bytes(W& dest, const T& source) -> decltype(source.write_bytes(dest))
{ return source.write_bytes(dest); }
}
namespace wire_write
{
/*! Don't add a function called `write_bytes` to this namespace, it will
prevent ADL lookup. ADL lookup delays the function searching until the
template is used instead of when its defined. This allows the unqualified
calls to `write_bytes` in this namespace to "find" user functions that are
declared after these functions. */
template<typename W, typename T>
inline void bytes(W& dest, const T& source)
{
write_bytes(dest, source); // ADL (searches every associated namespace)
}
//! Use writer `W` to convert `source` into bytes appended to `dest`.
template<typename W, typename T, typename U>
inline std::error_code to_bytes(T& dest, const U& source)
{
try
{
W out{std::move(dest)};
bytes(out, source);
dest = out.take_buffer();
}
catch (const wire::exception& e)
{
dest.clear();
return e.code();
}
catch (...)
{
dest.clear();
throw;
}
return {};
}
template<typename T>
inline std::size_t array_size(std::true_type, const T& source)
{ return boost::size(source); }
template<typename T>
inline constexpr std::size_t array_size(std::false_type, const T&) noexcept
{ return 0; }
template<typename W, typename T>
inline void array(W& dest, const T& source)
{
using value_type = typename T::value_type;
static_assert(!std::is_same<value_type, char>::value, "write array of chars as string");
static_assert(!std::is_same<value_type, std::int8_t>::value, "write array of signed chars as binary");
static_assert(!std::is_same<value_type, std::uint8_t>::value, "write array of unsigned chars as binary");
dest.start_array(array_size(dest.need_array_size(), source));
for (const auto& elem : source)
bytes(dest, elem);
dest.end_array();
}
template<typename W, typename T>
inline bool field(W& dest, const wire::field_<T, true>& field)
{
// Arrays always optional, see `wire/field.h`
if (wire::available(field))
{
dest.key(field.name);
bytes(dest, field.get_value());
}
return true;
}
template<typename W, typename T>
inline bool field(W& dest, const wire::field_<T, false>& field)
{
if (wire::available(field))
{
dest.key(field.name);
bytes(dest, *field.get_value());
}
return true;
}
template<typename W, typename T>
inline std::enable_if_t<std::is_pod<T>::value> dynamic_object_key(W& dest, const T& source)
{
dest.binary_key(epee::as_byte_span(source));
}
template<typename W>
inline void dynamic_object_key(W& dest, const boost::string_ref source)
{
dest.key(source);
}
template<typename W, typename T>
inline void dynamic_object(W& dest, const T& source)
{
dest.start_object(source.size());
for (const auto& elem : source)
{
dynamic_object_key(dest, elem.first);
bytes(dest, elem.second);
}
dest.end_object();
}
template<typename W, typename... T>
inline void object(W& dest, T&&... fields)
{
dest.start_object(wire::sum(std::size_t(wire::available(fields))...));
const bool dummy[] = {field(dest, std::forward<T>(fields))...};
dest.end_object();
(void)dummy; // expand into array to get 0,1,2,etc order
}
} // wire_write
namespace wire
{
template<typename W, typename T>
inline std::enable_if_t<is_array<T>::value> write_bytes(W& dest, const T& source)
{
wire_write::array(dest, source);
}
template<typename W, typename... T>
inline std::enable_if_t<std::is_base_of<writer, W>::value> object(W& dest, T... fields)
{
wire_write::object(dest, std::move(fields)...);
}
template<typename W, typename... T>
inline void object_fwd(const std::false_type /* is_read */, W& dest, T... fields)
{
wire::object(dest, std::move(fields)...);
}
}
