Add byte_stream for zero-copy serialization, and add support in ZMQ-JSON.

3 files changed, 137 insertions, 3 deletions

diff --git a/contrib/epee/src/CMakeLists.txt b/contrib/epee/src/CMakeLists.txt
index 88018d71a..ba6ad73ae 100644
--- a/contrib/epee/src/CMakeLists.txt
+++ b/contrib/epee/src/CMakeLists.txt
@@ -26,8 +26,9 @@
 # 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.
 
-add_library(epee STATIC byte_slice.cpp hex.cpp abstract_http_client.cpp http_auth.cpp mlog.cpp net_helper.cpp net_utils_base.cpp string_tools.cpp wipeable_string.cpp
-    levin_base.cpp memwipe.c connection_basic.cpp network_throttle.cpp network_throttle-detail.cpp mlocker.cpp buffer.cpp net_ssl.cpp
+
+add_library(epee STATIC byte_slice.cpp byte_stream.cpp hex.cpp abstract_http_client.cpp http_auth.cpp mlog.cpp net_helper.cpp net_utils_base.cpp string_tools.cpp
+    wipeable_string.cpp levin_base.cpp memwipe.c connection_basic.cpp network_throttle.cpp network_throttle-detail.cpp mlocker.cpp buffer.cpp net_ssl.cpp
     int-util.cpp)
 
 if (USE_READLINE AND (GNU_READLINE_FOUND OR (DEPENDS AND NOT MINGW)))
diff --git a/contrib/epee/src/byte_slice.cpp b/contrib/epee/src/byte_slice.cpp
index 3ad3b3e7e..99c37fae3 100644
--- a/contrib/epee/src/byte_slice.cpp
+++ b/contrib/epee/src/byte_slice.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) 2019, The Monero Project
+// Copyright (c) 2019-2020, The Monero Project
 //
 // All rights reserved.
 //
@@ -34,6 +34,7 @@
 #include <utility>
 
 #include "byte_slice.h"
+#include "byte_stream.h"
 
 namespace epee
 {
@@ -117,6 +118,12 @@ namespace epee
     }
   } // anonymous
 
+  void release_byte_buffer::operator()(std::uint8_t* buf) const noexcept
+  {
+    if (buf)
+      std::free(buf - sizeof(raw_byte_slice));
+  }
+
   byte_slice::byte_slice(byte_slice_data* storage, span<const std::uint8_t> portion) noexcept
     : storage_(storage), portion_(portion)
   {
@@ -163,6 +170,14 @@ namespace epee
     : byte_slice(adapt_buffer{}, std::move(buffer))
   {}
 
+  byte_slice::byte_slice(byte_stream&& stream) noexcept
+    : storage_(nullptr), portion_(stream.data(), stream.size())
+  {
+    std::uint8_t* const data = stream.take_buffer().release() - sizeof(raw_byte_slice);
+    new (data) raw_byte_slice{};
+    storage_.reset(reinterpret_cast<raw_byte_slice*>(data));
+  }
+
   byte_slice::byte_slice(byte_slice&& source) noexcept
     : storage_(std::move(source.storage_)), portion_(source.portion_)
   {
@@ -217,4 +232,29 @@ namespace epee
     portion_ = nullptr;
     return out;
   }
+
+  byte_buffer byte_buffer_resize(byte_buffer buf, const std::size_t length) noexcept
+  {
+    if (std::numeric_limits<std::size_t>::max() - sizeof(raw_byte_slice) < length)
+      return nullptr;
+
+    std::uint8_t* data = buf.get();
+    if (data != nullptr)
+      data -= sizeof(raw_byte_slice);
+
+    data = static_cast<std::uint8_t*>(std::realloc(data, sizeof(raw_byte_slice) + length));
+    if (data == nullptr)
+      return nullptr;
+
+    buf.release();
+    buf.reset(data + sizeof(raw_byte_slice));
+    return buf;
+  }
+
+  byte_buffer byte_buffer_increase(byte_buffer buf, const std::size_t current, const std::size_t more)
+  {
+    if (std::numeric_limits<std::size_t>::max() - current < more)
+      throw std::range_error{"byte_buffer_increase size_t overflow"};
+    return byte_buffer_resize(std::move(buf), current + more);
+  }
 } // epee
diff --git a/contrib/epee/src/byte_stream.cpp b/contrib/epee/src/byte_stream.cpp
new file mode 100644
index 000000000..e87d9f0bc
--- /dev/null
+++ b/contrib/epee/src/byte_stream.cpp
@@ -0,0 +1,93 @@
+// 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.
+
+#include "byte_stream.h"
+
+#include <algorithm>
+#include <limits>
+#include <utility>
+
+#include <iostream>
+
+namespace epee
+{
+  void byte_stream::overflow(const std::size_t requested)
+  {
+    // Recalculating `need` bytes removes at least one instruction from every
+    // inlined `put` call in header
+
+    assert(available() < requested);
+    const std::size_t need = requested - available();
+
+    const std::size_t len = size();
+    const std::size_t cap = capacity();
+    const std::size_t increase = std::max(need, increase_size());
+
+    next_write_ = nullptr;
+    end_ = nullptr;
+
+    buffer_ = byte_buffer_increase(std::move(buffer_), cap, increase);
+    if (!buffer_)
+      throw std::bad_alloc{};
+
+    next_write_ = buffer_.get() + len;
+    end_ = buffer_.get() + cap + increase;
+  }
+
+  byte_stream::byte_stream(byte_stream&& rhs) noexcept
+    : buffer_(std::move(rhs.buffer_)),
+      next_write_(rhs.next_write_),
+      end_(rhs.end_),
+      increase_size_(rhs.increase_size_)
+  {
+    rhs.next_write_ = nullptr;
+    rhs.end_ = nullptr;
+  }
+
+  byte_stream& byte_stream::operator=(byte_stream&& rhs) noexcept
+  {
+    if (this != std::addressof(rhs))
+    {
+      buffer_ = std::move(rhs.buffer_);
+      next_write_ = rhs.next_write_;
+      end_ = rhs.end_;
+      increase_size_ = rhs.increase_size_;
+      rhs.next_write_ = nullptr;
+      rhs.end_ = nullptr;
+    }
+    return *this;
+  }
+
+  byte_buffer byte_stream::take_buffer() noexcept
+  {
+    byte_buffer out{std::move(buffer_)};
+    next_write_ = nullptr;
+    end_ = nullptr;
+    return out;
+  }
+}