Shrink serializer buffers using buffers_ref

CHANGELOG.md

@@ -4,6 +4,7 @@ Version 75:
 * Construct buffer_prefix_view in-place
 * Shrink serializer buffers using buffers_ref
 * Tidy up BEAST_NO_BIG_VARIANTS
+* Shrink serializer buffers using buffers_ref
 
 --------------------------------------------------------------------------------
 

include/beast/core/detail/buffers_ref.hpp

@@ -0,0 +1,61 @@
+//
+// Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef BEAST_DETAIL_BUFFERS_REF_HPP
+#define BEAST_DETAIL_BUFFERS_REF_HPP
+
+#include <beast/core/type_traits.hpp>
+
+namespace beast {
+namespace detail {
+
+// A very lightweight reference to a buffer sequence
+template<class BufferSequence>
+class buffers_ref
+{
+    BufferSequence const& buffers_;
+
+public:
+    using value_type =
+        typename BufferSequence::value_type;
+
+    using const_iterator =
+        typename BufferSequence::const_iterator;
+
+    buffers_ref(buffers_ref const&) = default;
+
+    explicit
+    buffers_ref(BufferSequence const& buffers)
+        : buffers_(buffers)
+    {
+    }
+
+    const_iterator
+    begin() const
+    {
+        return buffers_.begin();
+    }
+
+    const_iterator
+    end() const
+    {
+        return buffers_.end();
+    }
+};
+
+// Return a reference to a buffer sequence
+template<class BufferSequence>
+buffers_ref<BufferSequence>
+make_buffers_ref(BufferSequence const& buffers)
+{
+    return buffers_ref<BufferSequence>(buffers);
+}
+
+} // detail
+} // beast
+
+#endif

include/beast/http/impl/serializer.ipp

@@ -8,6 +8,7 @@
 #ifndef BEAST_HTTP_IMPL_SERIALIZER_IPP
 #define BEAST_HTTP_IMPL_SERIALIZER_IPP
 
+#include <beast/core/detail/buffers_ref.hpp>
 #include <beast/http/error.hpp>
 #include <beast/http/status.hpp>
 #include <beast/core/detail/config.hpp>
@@ -53,6 +54,7 @@ serializer<isRequest, Body, Fields, ChunkDecorator>::
 next(error_code& ec, Visit&& visit)
 {
     using boost::asio::buffer_size;
+    using beast::detail::make_buffers_ref;
     switch(s_)
     {
     case do_construct:
@@ -90,14 +92,16 @@ next(error_code& ec, Visit&& visit)
     }
 
     case do_header:
-        visit(ec, boost::get<cb0_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<cb0_t>(v_)));
         break;
 
     go_header_only:
         v_ = ch_t{frd_->get()};
         s_ = do_header_only;
     case do_header_only:
-        visit(ec, boost::get<ch_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<ch_t>(v_)));
         break;
 
     case do_body:
@@ -124,7 +128,8 @@ next(error_code& ec, Visit&& visit)
     }
 
     case do_body + 2:
-        visit(ec, boost::get<cb1_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<cb1_t>(v_)));
         break;
 
     //----------------------------------------------------------------------
@@ -198,14 +203,16 @@ next(error_code& ec, Visit&& visit)
     }
 
     case do_header_c:
-        visit(ec, boost::get<ch0_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<ch0_t>(v_)));
         break;
 
     go_header_only_c:
         v_ = ch_t{frd_->get()};
         s_ = do_header_only_c;
     case do_header_only_c:
-        visit(ec, boost::get<ch_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<ch_t>(v_)));
         break;
 
     case do_body_c:
@@ -276,20 +283,23 @@ next(error_code& ec, Visit&& visit)
     }
 
     case do_body_c + 2:
-        visit(ec, boost::get<ch1_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<ch1_t>(v_)));
         break;
 
 #ifndef BEAST_NO_BIG_VARIANTS
     go_body_final_c:
         s_ = do_body_final_c;
     case do_body_final_c:
-        visit(ec, boost::get<ch2_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<ch2_t>(v_)));
         break;
 
     go_all_c:
         s_ = do_all_c;
     case do_all_c:
-        visit(ec, boost::get<ch3_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<ch3_t>(v_)));
         break;
 #endif
 
@@ -311,7 +321,8 @@ next(error_code& ec, Visit&& visit)
         BEAST_FALLTHROUGH;
 
     case do_final_c + 1:
-        visit(ec, boost::get<ch4_t>(v_));
+        visit(ec, make_buffers_ref(
+            boost::get<ch4_t>(v_)));
         break;
 
     //----------------------------------------------------------------------