buffers_adapter improvements:

* Add value()
* Add value_type
* Add in-place constructor

CHANGELOG.md

@@ -4,6 +4,7 @@ Version 173:
 * Fix buffers_adapter iterator value type
 * Fix buffers_adapter max_size
 * Fix buffers_prefix iterator decrement
+* buffers_adapter improvements
 
 --------------------------------------------------------------------------------
 

include/boost/beast/core/buffers_adapter.hpp

@@ -13,6 +13,7 @@
 #include <boost/beast/core/detail/config.hpp>
 #include <boost/beast/core/type_traits.hpp>
 #include <boost/asio/buffer.hpp>
+#include <boost/optional.hpp>
 #include <type_traits>
 
 namespace boost {
@@ -69,6 +70,9 @@ class buffers_adapter
     }
 
 public:
+    /// The type of the underlying mutable buffer sequence
+    using value_type = MutableBufferSequence;
+
 #if BOOST_BEAST_DOXYGEN
     /// The type used to represent the input sequence as a list of buffers.
     using const_buffers_type = implementation_defined;
@@ -104,6 +108,17 @@ public:
     explicit
     buffers_adapter(MutableBufferSequence const& buffers);
 
+    /** Constructor
+
+        This constructs the buffer adapter in-place from
+        a list of arguments.
+
+        @param args Arguments forwarded to the buffers constructor.
+    */
+    template<class... Args>
+    explicit
+    buffers_adapter(boost::in_place_init_t, Args&&... args);
+
     /// Returns the largest size output sequence possible.
     std::size_t
     max_size() const
@@ -125,6 +140,13 @@ public:
         return max_size_;
     }
 
+    /// Returns the original mutable buffer sequence
+    value_type const&
+    value() const
+    {
+        return bs_;
+    }
+
     /** Get a list of buffers that represents the output sequence, with the given size.
 
         @throws std::length_error if the size would exceed the limit

include/boost/beast/core/impl/buffers_adapter.ipp

@@ -17,6 +17,7 @@
 #include <cstring>
 #include <iterator>
 #include <stdexcept>
+#include <utility>
 
 namespace boost {
 namespace beast {
@@ -144,7 +145,8 @@ private:
 template<class MutableBufferSequence>
 inline
 auto
-buffers_adapter<MutableBufferSequence>::const_buffers_type::begin() const ->
+buffers_adapter<MutableBufferSequence>::
+const_buffers_type::begin() const ->
     const_iterator
 {
     return const_iterator{*ba_, ba_->begin_};
@@ -153,7 +155,8 @@ buffers_adapter<MutableBufferSequence>::const_buffers_type::begin() const ->
 template<class MutableBufferSequence>
 inline
 auto
-buffers_adapter<MutableBufferSequence>::const_buffers_type::end() const ->
+buffers_adapter<MutableBufferSequence>::
+const_buffers_type::end() const ->
     const_iterator
 {
     return const_iterator{*ba_, ba_->out_ ==
@@ -308,8 +311,8 @@ end() const ->
 //------------------------------------------------------------------------------
 
 template<class MutableBufferSequence>
-buffers_adapter<MutableBufferSequence>::buffers_adapter(
+buffers_adapter<MutableBufferSequence>::
-        buffers_adapter&& other)
+buffers_adapter(buffers_adapter&& other)
     : buffers_adapter(std::move(other),
         std::distance<iter_type>(boost::asio::buffer_sequence_begin(other.bs_), other.begin_),
         std::distance<iter_type>(boost::asio::buffer_sequence_begin(other.bs_), other.out_),
@@ -318,8 +321,8 @@ buffers_adapter<MutableBufferSequence>::buffers_adapter(
 }
 
 template<class MutableBufferSequence>
-buffers_adapter<MutableBufferSequence>::buffers_adapter(
+buffers_adapter<MutableBufferSequence>::
-        buffers_adapter const& other)
+buffers_adapter(buffers_adapter const& other)
     : buffers_adapter(other,
         std::distance<iter_type>(boost::asio::buffer_sequence_begin(other.bs_), other.begin_),
         std::distance<iter_type>(boost::asio::buffer_sequence_begin(other.bs_), other.out_),
@@ -329,8 +332,9 @@ buffers_adapter<MutableBufferSequence>::buffers_adapter(
 
 template<class MutableBufferSequence>
 auto
-buffers_adapter<MutableBufferSequence>::operator=(
+buffers_adapter<MutableBufferSequence>::
-    buffers_adapter&& other) -> buffers_adapter&
+operator=(buffers_adapter&& other) ->
+    buffers_adapter&
 {
     auto const nbegin = std::distance<iter_type>(
         boost::asio::buffer_sequence_begin(other.bs_),
@@ -355,8 +359,9 @@ buffers_adapter<MutableBufferSequence>::operator=(
 
 template<class MutableBufferSequence>
 auto
-buffers_adapter<MutableBufferSequence>::operator=(
+buffers_adapter<MutableBufferSequence>::
-    buffers_adapter const& other) -> buffers_adapter&
+operator=(buffers_adapter const& other) ->
+    buffers_adapter&
 {
     auto const nbegin = std::distance<iter_type>(
         boost::asio::buffer_sequence_begin(other.bs_),
@@ -380,8 +385,8 @@ buffers_adapter<MutableBufferSequence>::operator=(
 }
 
 template<class MutableBufferSequence>
-buffers_adapter<MutableBufferSequence>::buffers_adapter(
+buffers_adapter<MutableBufferSequence>::
-    MutableBufferSequence const& bs)
+buffers_adapter(MutableBufferSequence const& bs)
     : bs_(bs)
     , begin_(boost::asio::buffer_sequence_begin(bs_))
     , out_  (boost::asio::buffer_sequence_begin(bs_))
@@ -390,9 +395,22 @@ buffers_adapter<MutableBufferSequence>::buffers_adapter(
 {
 }
 
+template<class MutableBufferSequence>
+template<class... Args>
+buffers_adapter<MutableBufferSequence>::
+buffers_adapter(boost::in_place_init_t, Args&&... args)
+    : bs_{std::forward<Args>(args)...}
+    , begin_(boost::asio::buffer_sequence_begin(bs_))
+    , out_  (boost::asio::buffer_sequence_begin(bs_))
+    , end_  (boost::asio::buffer_sequence_begin(bs_))
+    , max_size_(boost::asio::buffer_size(bs_))
+{
+}
+
 template<class MutableBufferSequence>
 auto
-buffers_adapter<MutableBufferSequence>::prepare(std::size_t n) ->
+buffers_adapter<MutableBufferSequence>::
+prepare(std::size_t n) ->
     mutable_buffers_type
 {
     using boost::asio::buffer_size;
@@ -433,7 +451,8 @@ buffers_adapter<MutableBufferSequence>::prepare(std::size_t n) ->
 
 template<class MutableBufferSequence>
 void
-buffers_adapter<MutableBufferSequence>::commit(std::size_t n)
+buffers_adapter<MutableBufferSequence>::
+commit(std::size_t n)
 {
     using boost::asio::buffer_size;
     if(out_ == end_)
@@ -469,7 +488,8 @@ buffers_adapter<MutableBufferSequence>::commit(std::size_t n)
 template<class MutableBufferSequence>
 inline
 auto
-buffers_adapter<MutableBufferSequence>::data() const ->
+buffers_adapter<MutableBufferSequence>::
+data() const ->
     const_buffers_type
 {
     return const_buffers_type{*this};
@@ -477,7 +497,8 @@ buffers_adapter<MutableBufferSequence>::data() const ->
 
 template<class MutableBufferSequence>
 void
-buffers_adapter<MutableBufferSequence>::consume(std::size_t n)
+buffers_adapter<MutableBufferSequence>::
+consume(std::size_t n)
 {
     using boost::asio::buffer_size;
     while(begin_ != out_)

test/beast/core/buffers_adapter.cpp

@@ -104,7 +104,8 @@ public:
                 BEAST_EXPECT(buffer_size(d) == 0);
             }
             {
-                auto d = ba.prepare(z); BEAST_EXPECT(buffer_size(d) == z);
+                auto d = ba.prepare(z);
+                BEAST_EXPECT(buffer_size(d) == z);
                 ba.commit(buffer_copy(d, buffer(s.data()+x+y, z)));
             }
             ba.commit(2);