Use the exchange() idiom in move constructors

fix #1203

CHANGELOG.md

@@ -1,3 +1,9 @@
+Version 179:
+
+* Use the exchange() idiom in move constructors
+
+--------------------------------------------------------------------------------
+
 Version 178:
 
 * Use static_cast instead

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

@@ -24,6 +24,7 @@
 # endif
 #endif
 
+#include <boost/core/exchange.hpp>
 #include <limits>
 #include <fcntl.h>
 #include <sys/types.h>
@@ -65,9 +66,8 @@ file_posix::
 inline
 file_posix::
 file_posix(file_posix&& other)
-    : fd_(other.fd_)
+    : fd_(boost::exchange(other.fd_, -1))
 {
-    other.fd_ = -1;
 }
 
 inline

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

@@ -10,6 +10,7 @@
 #ifndef BOOST_BEAST_CORE_IMPL_FILE_STDIO_IPP
 #define BOOST_BEAST_CORE_IMPL_FILE_STDIO_IPP
 
+#include <boost/core/exchange.hpp>
 #include <limits>
 
 namespace boost {
@@ -26,9 +27,8 @@ file_stdio::
 inline
 file_stdio::
 file_stdio(file_stdio&& other)
-    : f_(other.f_)
+    : f_(boost::exchange(other.f_, nullptr))
 {
-    other.f_ = nullptr;
 }
 
 inline

include/boost/beast/core/impl/file_win32.ipp

@@ -10,6 +10,7 @@
 #ifndef BOOST_BEAST_CORE_IMPL_FILE_WIN32_IPP
 #define BOOST_BEAST_CORE_IMPL_FILE_WIN32_IPP
 
+#include <boost/core/exchange.hpp>
 #include <boost/winapi/access_rights.hpp>
 #include <boost/winapi/error_codes.hpp>
 #include <boost/winapi/file_management.hpp>
@@ -61,9 +62,8 @@ file_win32::
 inline
 file_win32::
 file_win32(file_win32&& other)
-    : h_(other.h_)
+    : h_(boost::exchange(other.h_, boost::winapi::INVALID_HANDLE_VALUE_))
 {
-    other.h_ = boost::winapi::INVALID_HANDLE_VALUE_;
 }
 
 inline

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

@@ -10,6 +10,7 @@
 #ifndef BOOST_BEAST_IMPL_FLAT_BUFFER_HPP
 #define BOOST_BEAST_IMPL_FLAT_BUFFER_HPP
 
+#include <boost/core/exchange.hpp>
 #include <boost/assert.hpp>
 #include <boost/throw_exception.hpp>
 #include <stdexcept>
@@ -86,18 +87,14 @@ basic_flat_buffer<Allocator>::
 basic_flat_buffer(basic_flat_buffer&& other)
     : detail::empty_base_optimization<base_alloc_type>(
         std::move(other.member()))
-    , begin_(other.begin_)
-    , in_(other.in_)
-    , out_(other.out_)
+    , begin_(boost::exchange(other.begin_, nullptr))
+    , in_(boost::exchange(other.in_, nullptr))
+    , out_(boost::exchange(other.out_, nullptr))
     , last_(out_)
-    , end_(other.end_)
+    , end_(boost::exchange(other.end_, nullptr))
     , max_(other.max_)
 {
-    other.begin_ = nullptr;
-    other.in_ = nullptr;
-    other.out_ = nullptr;
     other.last_ = nullptr;
-    other.end_ = nullptr;
 }
 
 template<class Allocator>

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

@@ -11,6 +11,7 @@
 #define BOOST_BEAST_IMPL_MULTI_BUFFER_IPP
 
 #include <boost/beast/core/detail/type_traits.hpp>
+#include <boost/core/exchange.hpp>
 #include <boost/assert.hpp>
 #include <boost/throw_exception.hpp>
 #include <algorithm>
@@ -462,20 +463,16 @@ basic_multi_buffer(basic_multi_buffer&& other)
     : detail::empty_base_optimization<
         base_alloc_type>(std::move(other.member()))
     , max_(other.max_)
-    , in_size_(other.in_size_)
-    , in_pos_(other.in_pos_)
-    , out_pos_(other.out_pos_)
-    , out_end_(other.out_end_)
+    , in_size_(boost::exchange(other.in_size_, 0))
+    , in_pos_(boost::exchange(other.in_pos_, 0))
+    , out_pos_(boost::exchange(other.out_pos_, 0))
+    , out_end_(boost::exchange(other.out_end_, 0))
 {
     auto const at_end =
         other.out_ == other.list_.end();
     list_ = std::move(other.list_);
     out_ = at_end ? list_.end() : other.out_;
-    other.in_size_ = 0;
     other.out_ = other.list_.end();
-    other.in_pos_ = 0;
-    other.out_pos_ = 0;
-    other.out_end_ = 0;
 }
 
 template<class Allocator>

include/boost/beast/http/impl/fields.ipp

@@ -18,6 +18,7 @@
 #include <boost/beast/http/rfc7230.hpp>
 #include <boost/beast/http/status.hpp>
 #include <boost/beast/http/chunk_encode.hpp>
+#include <boost/core/exchange.hpp>
 #include <boost/throw_exception.hpp>
 #include <stdexcept>
 #include <string>
@@ -363,11 +364,9 @@ basic_fields(basic_fields&& other) noexcept
         std::move(other.member()))
     , set_(std::move(other.set_))
     , list_(std::move(other.list_))
-    , method_(other.method_)
-    , target_or_reason_(other.target_or_reason_)
+    , method_(boost::exchange(other.method_, {}))
+    , target_or_reason_(boost::exchange(other.target_or_reason_, {}))
 {
-    other.method_ = {};
-    other.target_or_reason_ = {};
 }
 
 template<class Allocator>

include/boost/beast/websocket/detail/stream_base.hpp

@@ -20,6 +20,7 @@
 #include <boost/beast/core/detail/integer_sequence.hpp>
 #include <boost/align/aligned_alloc.hpp>
 #include <boost/asio/buffer.hpp>
+#include <boost/core/exchange.hpp>
 #include <atomic>
 #include <cstdint>
 #include <memory>
@@ -50,9 +51,8 @@ public:
     soft_mutex& operator=(soft_mutex const&) = delete;
 
     soft_mutex(soft_mutex&& other) noexcept
-        : id_(other.id_)
+        : id_(boost::exchange(other.id_, 0))
     {
-        other.id_ = 0;
     }
 
     soft_mutex& operator=(soft_mutex&& other) noexcept
@@ -156,12 +156,7 @@ struct stream_prng
         }
 
         prng_ref(prng_ref&& other)
-            : p_([&other]
-                {
-                    auto p = other.p_;
-                    other.p_ = nullptr;
-                    return p;
-                }())
+            : p_(boost::exchange(other.p_, nullptr))
         {
         }