From 39697ea37f3f9402d0a545c1f9e427bd3bd65237 Mon Sep 17 00:00:00 2001
From: Vinnie Falco <vinnie.falco@gmail.com>
Date: Sat, 20 May 2017 19:46:30 -0700
Subject: [PATCH] Additional constructors for consuming_buffers

---
 CHANGELOG.md                                  |  1 +
 include/beast/core/consuming_buffers.hpp      | 11 +++++
 include/beast/core/impl/consuming_buffers.ipp | 23 +++++++++++
 test/core/consuming_buffers.cpp               | 40 +++++++++++++++++--
 4 files changed, 72 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e52e7ef3..36bc0863 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ Version 43
 * Fix strict aliasing warnings in buffers_view
 * Tidy up buffer_prefix overloads and test
 * Add write limit to test::string_ostream
+* Additional constructors for consuming_buffers
 
 --------------------------------------------------------------------------------
 
diff --git a/include/beast/core/consuming_buffers.hpp b/include/beast/core/consuming_buffers.hpp
index cd32baa9..9c9f1dee 100644
--- a/include/beast/core/consuming_buffers.hpp
+++ b/include/beast/core/consuming_buffers.hpp
@@ -10,6 +10,7 @@
 
 #include <beast/config.hpp>
 #include <boost/asio/buffer.hpp>
+#include <boost/optional.hpp>
 #include <cstdint>
 #include <iterator>
 #include <type_traits>
@@ -78,6 +79,9 @@ public:
 
 #endif
 
+    /// Default constructor.
+    consuming_buffers();
+
     /// Move constructor.
     consuming_buffers(consuming_buffers&&);
 
@@ -98,6 +102,13 @@ public:
     explicit
     consuming_buffers(BufferSequence const& buffers);
 
+    /** Construct a buffer sequence in-place.
+
+        @param args Arguments forwarded to the contained buffers constructor.
+    */
+    template<class... Args>
+    consuming_buffers(boost::in_place_init_t, Args&&... args);
+
     /// Get a bidirectional iterator to the first element.
     const_iterator
     begin() const;
diff --git a/include/beast/core/impl/consuming_buffers.ipp b/include/beast/core/impl/consuming_buffers.ipp
index 4cc90a9c..d22ddf2b 100644
--- a/include/beast/core/impl/consuming_buffers.ipp
+++ b/include/beast/core/impl/consuming_buffers.ipp
@@ -109,6 +109,14 @@ private:
     }
 };
 
+template<class BufferSequence>
+consuming_buffers<BufferSequence>::
+consuming_buffers()
+    : begin_(bs_.begin())
+    , end_(bs_.end())
+{
+}
+
 template<class BufferSequence>
 consuming_buffers<BufferSequence>::
 consuming_buffers(consuming_buffers&& other)
@@ -167,6 +175,21 @@ consuming_buffers(BufferSequence const& bs)
             "BufferSequence requirements not met");
 }
 
+template<class BufferSequence>
+template<class... Args>
+consuming_buffers<BufferSequence>::
+consuming_buffers(boost::in_place_init_t, Args&&... args)
+    : bs_(std::forward<Args>(args)...)
+    , begin_(bs_.begin())
+    , end_(bs_.end())
+{
+    static_assert(sizeof...(Args) > 0,
+        "Missing constructor arguments");
+    static_assert(
+        std::is_constructible<BufferSequence, Args...>::value,
+            "BufferSequence is not constructible from arguments");
+}
+
 template<class BufferSequence>
 inline
 auto
diff --git a/test/core/consuming_buffers.cpp b/test/core/consuming_buffers.cpp
index 2a10ab00..afd43f58 100644
--- a/test/core/consuming_buffers.cpp
+++ b/test/core/consuming_buffers.cpp
@@ -9,6 +9,7 @@
 #include <beast/core/consuming_buffers.hpp>
 
 #include "buffer_test.hpp"
+#include <beast/core/buffer_cat.hpp>
 #include <beast/core/ostream.hpp>
 #include <beast/unit_test/suite.hpp>
 #include <boost/asio/buffer.hpp>
@@ -56,7 +57,8 @@ public:
         BEAST_EXPECT(test::size_rev_post(buffers) == n);
     }
 
-    void testMatrix()
+    void
+    testMatrix()
     {
         using boost::asio::buffer;
         using boost::asio::const_buffer;
@@ -98,8 +100,37 @@ public:
         }
         }}}}
     }
+    
+    void
+    testDefaultCtor()
+    {
+        class test_buffer : public boost::asio::const_buffers_1
+        {
+        public:
+            test_buffer()
+                : boost::asio::const_buffers_1("\r\n", 2)
+            {
+            }
+        };
 
-    void testNullBuffers()
+        consuming_buffers<test_buffer> cb;
+        BEAST_EXPECT(to_string(cb) == "\r\n");
+    }
+
+    void
+    testInPlace()
+    {
+        consuming_buffers<buffers_view<
+            boost::asio::const_buffers_1,
+            boost::asio::const_buffers_1>> cb(
+                boost::in_place_init,
+                    boost::asio::const_buffers_1("\r", 1),
+                    boost::asio::const_buffers_1("\n", 1));
+        BEAST_EXPECT(to_string(cb) == "\r\n");
+    }
+
+    void
+    testNullBuffers()
     {
         using boost::asio::buffer_copy;
         using boost::asio::buffer_size;
@@ -112,7 +143,8 @@ public:
         BEAST_EXPECT(buffer_copy(cb2, cb) == 0);
     }
 
-    void testIterator()
+    void
+    testIterator()
     {
         using boost::asio::const_buffer;
         std::array<const_buffer, 3> ba;
@@ -126,6 +158,8 @@ public:
     void run() override
     {
         testMatrix();
+        testDefaultCtor();
+        testInPlace();
         testNullBuffers();
         testIterator();
     }