Adding msgpack support to ::wire:: library (#63)

src/wire/msgpack/read.h

@@ -0,0 +1,164 @@
+// 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 <cstddef>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+#include "wire/field.h"
+#include "wire/msgpack/base.h"
+#include "wire/read.h"
+#include "wire/traits.h"
+
+namespace wire
+{
+  //! Reads MSGPACK tokens one-at-a-time for DOMless parsing
+  class msgpack_reader : public reader
+  {
+    epee::byte_slice source_;
+    std::size_t remaining_; //!< Expected number of elements remaining
+
+    //! \throw std::logic_error
+    [[noreturn]] void throw_logic_error();
+    //! Decrement remaining_ if not zero, \throw std::logic_error when `remaining_ == 0`.
+    void update_remaining()
+    {
+      if (remaining_)
+        --remaining_;
+      else
+        throw_logic_error();
+    }
+    
+    //! Skips next value. \throw wire::exception if invalid JSON syntax.
+    void skip_value();
+
+    //! \return Next tag but leave `source_` untouched.
+    msgpack::tag peek_tag();
+    //! \return Next tag and remove first byte from `source_`.
+    msgpack::tag get_tag();
+
+    //! \return Integer from `soure_` where positive fixed tag has been checked.
+    std::intmax_t do_integer(msgpack::tag);
+    //! \return Integer from `source_` where fixed tag has been checked.
+    std::uintmax_t do_unsigned_integer(msgpack::tag);
+
+    //! \return Number of items determined by `T` fixed tag and `U` tuple of tags.
+    template<typename T, typename U>
+    std::size_t read_count(error::schema);
+
+  public:
+    explicit msgpack_reader(epee::byte_slice&& source)
+      : reader(), source_(std::move(source)), remaining_(1)
+    {}
+
+    //! \throw wire::exception if JSON parsing is incomplete.
+    void check_complete() const override final;
+
+    //! \throw wire::exception if next token not a boolean.
+    bool boolean() override final;
+
+    //! \throw wire::expception if next token not an integer.
+    std::intmax_t integer() override final
+    {
+      update_remaining();
+      const msgpack::tag next = get_tag();
+      if (std::uint8_t(next) <= msgpack::ftag_unsigned::max())
+        return std::uint8_t(next);
+      return do_integer(next);
+    }
+
+    //! \throw wire::exception if next token not an unsigned integer.
+    std::uintmax_t unsigned_integer() override final
+    {
+      update_remaining();
+      const msgpack::tag next = get_tag();
+      if (std::uint8_t(next) <= msgpack::ftag_unsigned::max())
+        return std::uint8_t(next);
+      return do_unsigned_integer(next);
+    }
+
+    //! \throw wire::exception if next token not a valid real number
+    double real() override final;
+
+    //! \throw wire::exception if next token not a string
+    std::string string() override final;
+
+    //! \throw wire::exception if next token cannot be read as hex
+    std::vector<std::uint8_t> binary() override final;
+
+    //! \throw wire::exception if next token cannot be read as hex into `dest`.
+    void binary(epee::span<std::uint8_t> dest) override final;
+
+    //! \throw wire::exception if invalid next token invalid enum. \return Index in `enums`.
+    std::size_t enumeration(epee::span<char const* const> enums) override final;
+
+
+    //! \throw wire::exception if next token not `[`.
+    std::size_t start_array() override final;
+
+    //! \return true when `count == 0`.
+    bool is_array_end(const std::size_t count) override final;
+
+
+    //! \throw wire::exception if next token not `{`.
+    std::size_t start_object() override final;
+
+    /*! \throw wire::exception if next token not key or `}`.
+        \param[out] index of key match within `map`.
+        \return True if another value to read. */
+    bool key(epee::span<const key_map> map, std::size_t&, std::size_t& index) override final;
+  };
+
+
+  // Don't call `read` directly in this namespace, do it from `wire_read`.
+
+  template<typename T>
+  expect<T> msgpack::from_bytes(epee::byte_slice&& bytes)
+  {
+    msgpack_reader source{std::move(bytes)};
+    return wire_read::to<T>(source);
+  }
+
+  // specialization prevents type "downgrading" to base type in cpp files
+
+  template<typename T>
+  inline void array(msgpack_reader& source, T& dest)
+  {
+    wire_read::array(source, dest);
+  }
+
+  template<typename... T>
+  inline void object(msgpack_reader& source, T... fields)
+  {
+    wire_read::object(source, wire_read::tracker<T>{std::move(fields)}...);
+  }
+} // wire