Initial working base separated from top-level monero project

src/wire/write.h

@@ -0,0 +1,224 @@
+// Copyright (c) 2020, 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 <array>
+#include <boost/utility/string_ref.hpp>
+#include <cstdint>
+#include <type_traits>
+
+#include "byte_slice.h" // monero/contrib/epee/include
+#include "span.h"       // monero/contrib/epee/include
+#include "wire/field.h"
+#include "wire/filters.h"
+#include "wire/traits.h"
+
+namespace wire
+{
+  //! Interface for converting C/C++ objects to "wire" (byte) formats.
+  struct writer
+  {
+    writer() = default;
+
+    virtual ~writer() noexcept;
+
+    virtual void integer(int) = 0;
+    virtual void integer(std::intmax_t) = 0;
+
+    virtual void unsigned_integer(unsigned) = 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> bytes) = 0;
+
+    virtual void enumeration(std::size_t index, epee::span<char const* const> enums) = 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(std::uintmax_t) = 0;
+    virtual void key(boost::string_ref) = 0;
+    virtual void key(unsigned, boost::string_ref) = 0; //!< Implementation should output fastest key
+    virtual void end_object() = 0;
+
+  protected:
+    writer(const writer&) = default;
+    writer(writer&&) = default;
+    writer& operator=(const writer&) = default;
+    writer& operator=(writer&&) = default;
+  };
+
+  // leave in header, compiler can de-virtualize when final type is given
+
+  inline void write_bytes(writer& dest, const int source)
+  {
+    dest.integer(source);
+  }
+  inline void write_bytes(writer& dest, const std::intmax_t source)
+  {
+    dest.integer(source);
+  }
+
+  inline void write_bytes(writer& dest, const unsigned source)
+  {
+    dest.unsigned_integer(source);
+  }
+  inline void write_bytes(writer& dest, const std::uintmax_t source)
+  {
+    dest.unsigned_integer(source);
+  }
+
+  inline void write_bytes(writer& dest, const double source)
+  {
+    dest.real(source);
+  }
+
+  inline void write_bytes(writer& dest, const boost::string_ref source)
+  {
+    dest.string(source);
+  }
+
+  template<typename T>
+  inline enable_if<is_blob<T>::value> write_bytes(writer& dest, const T& source)
+  {
+    dest.binary(epee::as_byte_span(source));
+  }
+
+  inline void write_bytes(writer& dest, const epee::span<const std::uint8_t> source)
+  {
+    dest.binary(source);
+  }
+}
+
+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 epee::byte_slice to_bytes(const T& value)
+  {
+    W dest{};
+    write_bytes(dest, value);
+    return dest.take_bytes();
+  }
+
+  template<typename W, typename T, typename F = wire::identity_>
+  inline void array(W& dest, const T& source, const std::size_t count, F filter = F{})
+  {
+    using value_type = typename T::value_type;
+    static_assert(!std::is_same<value_type, char>::value, "write array of chars as binary");
+    static_assert(!std::is_same<value_type, std::uint8_t>::value, "write array of unsigned chars as binary");
+
+    dest.start_array(count);
+    for (const auto& elem : source)
+      write_bytes(dest, filter(elem));
+    dest.end_array();
+  }
+
+  template<typename W, typename T>
+  inline bool field(W& dest, const wire::field_<T, true> elem)
+  {
+    dest.key(0, elem.name);
+    write_bytes(dest, elem.get_value());
+    return true;
+  }
+
+  template<typename W, typename T>
+  inline bool field(W& dest, const wire::field_<T, false> elem)
+  {
+    if (bool(elem.get_value()))
+    {
+      dest.key(0, elem.name);
+      write_bytes(dest, *elem.get_value());
+    }
+    return true;
+  }
+
+  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::move(fields))...};
+    dest.end_object();
+  }
+
+  template<typename W, typename T, typename F, typename G>
+  inline void dynamic_object(W& dest, const T& values, const std::size_t count, F key_filter, G value_filter)
+  {
+    dest.start_object(count);
+    for (const auto& elem : values)
+    {
+      dest.key(key_filter(elem.first));
+      write_bytes(dest, value_filter(elem.second));
+    }
+    dest.end_object();
+  }
+} // wire_write
+
+namespace wire
+{
+  template<typename T, typename F = identity_>
+  inline void array(writer& dest, const T& source, F filter = F{})
+  {
+    wire_write::array(dest, source, source.size(), std::move(filter));
+  }
+  template<typename T, typename F>
+  inline void write_bytes(writer& dest, as_array_<T, F> source)
+  {
+    wire::array(dest, source.get_value(), std::move(source.filter));
+  }
+  template<typename T>
+  inline enable_if<is_array<T>::value> write_bytes(writer& dest, const T& source)
+  {
+    wire::array(dest, source);
+  }
+
+  template<typename T, typename F = identity_, typename G = identity_>
+  inline void dynamic_object(writer& dest, const T& source, F key_filter = F{}, G value_filter = G{})
+  {
+    wire_write::dynamic_object(dest, source, source.size(), std::move(key_filter), std::move(value_filter));
+  }
+  template<typename T, typename F, typename G>
+  inline void write_bytes(writer& dest, as_object_<T, F, G> source)
+  {
+    wire::dynamic_object(dest, source.get_map(), std::move(source.key_filter), std::move(source.value_filter));
+  }
+
+  template<typename... T>
+  inline void object(writer& dest, T... fields)
+  {
+    wire_write::object(dest, std::move(fields)...);
+  }
+}