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

src/wire/msgpack/write.h

@@ -0,0 +1,225 @@
+// 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 <array>
+#include <boost/utility/string_ref.hpp>
+#include <cstdint>
+#include <iosfwd>
+#include <limits>
+
+#include "byte_stream.h" // monero/contrib/epee/include
+#include "span.h"        // monero/contrib/epee/include
+#include "wire/field.h"
+#include "wire/filters.h"
+#include "wire/msgpack/base.h"
+#include "wire/traits.h"
+#include "wire/write.h"
+
+namespace wire
+{
+  //! Writes MSGPACK tokens one-at-a-time for DOMless output.
+  class msgpack_writer : public writer
+  {
+    epee::byte_stream bytes_;
+    std::size_t expected_; //! Tracks number of expected elements remaining
+    const bool integer_keys_;
+    bool needs_flush_;
+
+    //! Provided data currently in `bytes_`.
+    virtual void do_flush(epee::span<const uint8_t>);
+
+    //! Flush written bytes to `do_flush(...)` if configured
+    void check_flush();
+    
+    void do_integer(std::intmax_t);
+    void do_unsigned_integer(std::uintmax_t);
+    
+    template<typename T>
+    void integer_t(const T value)
+    {
+      if (0 <= value)
+      {
+        if (value <= msgpack::ftag_unsigned::max())
+          bytes_.put(std::uint8_t(value));
+        else // if multibyte
+          do_unsigned_integer(std::uintmax_t(value));
+      }
+      else // if negative
+        do_integer(value);
+      --expected_;
+    }
+
+    template<typename T>
+    void unsigned_integer_t(const T value)
+    {
+      if (value <= msgpack::ftag_unsigned::max())
+        bytes_.put(std::uint8_t(value));
+      else // if multibyte
+        do_unsigned_integer(value);
+      --expected_;
+    }
+
+  protected:
+    msgpack_writer(bool integer_keys, bool needs_flush)
+      : writer(), bytes_(), expected_(1), integer_keys_(integer_keys), needs_flush_(needs_flush)
+    {}
+
+    //! \throw std::logic_error if tree was not completed
+    void check_complete();
+
+    //! \throw std::logic_error if incomplete msgpack tree. \return msgpack bytes
+    epee::byte_slice take_msgpack();
+
+    //! Flush bytes in local buffer to `do_flush(...)`
+    void flush()
+    {
+      do_flush({bytes_.data(), bytes_.size()});
+      bytes_.clear();
+    }
+
+  public:
+    msgpack_writer(const msgpack_writer&) = delete;
+    virtual ~msgpack_writer() noexcept;
+    msgpack_writer& operator=(const msgpack_writer&) = delete;
+
+    void boolean(const bool value) override final
+    {
+      if (value)
+        bytes_.put(std::uint8_t(msgpack::tag::True));
+      else
+        bytes_.put(std::uint8_t(msgpack::tag::False));
+      --expected_;
+    }
+
+    void integer(const int value) override final
+    { integer_t(value); }
+
+    void integer(const std::intmax_t value) override final
+    { integer_t(value); }
+
+    void unsigned_integer(const unsigned value) override final
+    { unsigned_integer_t(value); }
+
+    void unsigned_integer(const std::uintmax_t value) override final
+    { unsigned_integer_t(value); }
+
+    void real(double) override final;
+
+    //! \throw wire::exception if `source.size()` exceeds 2^32-1
+    void string(boost::string_ref source) override final;
+    //! \throw wire::exception if `source.size()` exceeds 2^32-1
+    void binary(epee::span<const std::uint8_t> source) override final;
+
+    void enumeration(std::size_t index, epee::span<char const* const> enums) override final;
+
+    //! \throw wire::exception if `items` exceeds 2^32-1.
+    void start_array(std::size_t items) override final;
+    void end_array() override final { --expected_; }
+
+    //! \throw wire::exception if `items` exceeds 2^32-1
+    void start_object(std::size_t items) override final;
+    void key(std::uintmax_t) override final;
+    void key(boost::string_ref) override final;
+    void key(unsigned, boost::string_ref) override final;
+    void end_object() override final { --expected_; }
+  };
+
+  //! Buffers entire JSON message in memory
+  struct msgpack_slice_writer final : msgpack_writer
+  {
+    explicit msgpack_slice_writer(bool integer_keys = false)
+      : msgpack_writer(integer_keys, false)
+    {}
+
+    //! \throw std::logic_error if incomplete JSON tree \return JSON bytes
+    epee::byte_slice take_bytes()
+    {
+      return msgpack_writer::take_msgpack();
+    }
+  };
+
+  //! Periodically flushes JSON data to `std::ostream`
+  class msgpack_stream_writer final : public msgpack_writer
+  {
+    std::ostream& dest;
+
+    virtual void do_flush(epee::span<const std::uint8_t>) override final;
+  public:
+    explicit msgpack_stream_writer(std::ostream& dest, bool integer_keys = false)
+      : msgpack_writer(integer_keys, true), dest(dest)
+    {}
+
+    //! Flush remaining bytes to stream \throw std::logic_error if incomplete JSON tree
+    void finish()
+    {
+      check_complete();
+      flush();
+    }
+  };
+
+  template<typename T>
+  epee::byte_slice msgpack::to_bytes(const T& source)
+  {
+    return wire_write::to_bytes<msgpack_slice_writer>(source);
+  }
+
+  template<typename T, typename F = identity_>
+  inline void array(msgpack_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(msgpack_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(msgpack_writer& dest, const T& source)
+  {
+    wire::array(dest, source);
+  }
+
+  template<typename T, typename F = identity_, typename G = identity_>
+  inline void dynamic_object(msgpack_writer& dest, const T& source, F key_filter = F{}, G value_filter = G{})
+  {
+    // works with "lazily" computed ranges
+    wire_write::dynamic_object(dest, source, 0, std::move(key_filter), std::move(value_filter));
+  }
+  template<typename T, typename F, typename G>
+  inline void write_bytes(msgpack_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(msgpack_writer& dest, T... fields)
+  {
+    wire_write::object(dest, std::move(fields)...);
+  }
+}