deprecated buffer_cast has been dropped in boost 1.87.0

[heitbaum]

snapcast 0.29.0 does not compile with boost-1.87.0

snapcast/server/stream_session_ws.cpp

Line 117 in f6ce4f3

auto* data = boost::asio::buffer_cast<char*>(buffer_.data());

• boostorg/asio@7d1aac2

FAILED: server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o
/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/bin/x86_64-libreelec-linux-gnu-g++ -DBOOST_ASIO_NO_TS_EXECUTORS -DBOOST_ERROR_CODE_HEADER_ONLY -DHAS_ALSA -DHAS_AVAHI -DHAS_DAEMON -DHAS_EXPAT -DHAS_FLAC -DHAS_OGG -DHAS_OPUS -DHAS_PULSE -DHAS_SOXR -DHAS_VORBIS -DHAS_VORBIS_ENC -DVERSION=\"0.29.0\" -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0 -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0/include -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0/server -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/x86_64-libreelec-linux-gnu/sysroot/usr/include/dbus-1.0 -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/x86_64-libreelec-linux-gnu/sysroot/usr/lib/dbus-1.0/include -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/x86_64-libreelec-linux-gnu/sysroot/usr/include/opus -march=x86-64-v3 -Wall -pipe  -O2 -fomit-frame-pointer -DNDEBUG -pthread
            -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/install_pkg/aixlog-1.5.0/usr/include                       -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/install_pkg/asio-1.31.0/usr/include                       -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/install_pkg/popl-1.3.0/usr/include -std=gnu++17 -Wall -Wextra -pedantic -Wno-unused-function -MD -MT server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o -MF server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o.d -o server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o -c /var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0/server/stream_session_ws.cpp
../server/stream_session_ws.cpp: In member function 'void StreamSessionWebsocket::on_read_ws(boost::beast::error_code, std::size_t)':
../server/stream_session_ws.cpp:117:31: error: 'buffer_cast' is not a member of 'boost::asio'; did you mean 'buffer_copy'?
  117 |     auto* data = boost::asio::buffer_cast<char*>(buffer_.data());
      |                               ^~~~~~~~~~~
      |                               buffer_copy
../server/stream_session_ws.cpp:117:43: error: expected primary-expression before 'char'
  117 |     auto* data = boost::asio::buffer_cast<char*>(buffer_.data());
      |                                           ^~~~

This will be the final fix (now that #1310 is queued) to remove all boost 1.87.0 deprecated code.

[heitbaum]

In trying to fix this based on the boost documentation https://www.boost.org/doc/libs/1_85_0/doc/html/boost_asio/reference/mutable_buffer.html. The following compile error occurs. Previous version of the documentation https://www.boost.org/doc/libs/1_65_0/doc/html/boost_asio/reference/mutable_buffer.html.

--- a/server/stream_session_ws.cpp
+++ b/server/stream_session_ws.cpp
@@ -114,7 +114,7 @@ void StreamSessionWebsocket::on_read_ws(beast::error_code ec, std::size_t bytes_
���������return;
�����}

-    auto* data = boost::asio::buffer_cast<char*>(buffer_.data());
+    auto* data = static_cast<char*>(buffer_.data());
�����baseMessage_.deserialize(data);
�����LOG(DEBUG, LOG_TAG) << "getNextMessage: " << baseMessage_.type << ", size: " << baseMessage_.size << ", id: " << baseMessage_.id
�������������������������<< ", refers: " << baseMessage_.refersTo << "\n";

error

[54/56] Building CXX object server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o
FAILED: server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o 
/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/bin/x86_64-libreelec-linux-gnu-g++ -DBOOST_ASIO_NO_TS_EXECUTORS -DBOOST_ERROR_CODE_HEADER_ONLY -DHAS_ALSA -DHAS_AVAHI -DHAS_DAEMON -DHAS_EXPAT -DHAS_FLAC -DHAS_OGG -DHAS_OPUS -DHAS_PULSE -DHAS_SOXR -DHAS_VORBIS -DHAS_VORBIS_ENC -DVERSION=\"0.29.0\" -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0 -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0/include -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0/server -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/x86_64-libreelec-linux-gnu/sysroot/usr/include/dbus-1.0 -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/x86_64-libreelec-linux-gnu/sysroot/usr/lib/dbus-1.0/include -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/toolchain/x86_64-libreelec-linux-gnu/sysroot/usr/include/opus -march=x86-64-v3 -Wall -pipe  -O2 -fomit-frame-pointer -DNDEBUG -pthread                       -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/install_pkg/aixlog-1.5.0/usr/include                       -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/install_pkg/asio-1.31.0/usr/include                       -I/var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/install_pkg/popl-1.3.0/usr/include -std=gnu++17 -Wall -Wextra -pedantic -Wno-unused-function -MD -MT server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o -MF server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o.d -o server/CMakeFiles/snapserver.dir/stream_session_ws.cpp.o -c /var/media/DATA/home-rudi/LibreELEC.tv/build.LibreELEC-Generic.x86_64-13.0-devel/build/snapcast-0.29.0/server/stream_session_ws.cpp
../server/stream_session_ws.cpp: In member function 'void StreamSessionWebsocket::on_read_ws(boost::beast::error_code, std::size_t)':
../server/stream_session_ws.cpp:117:18: error: invalid 'static_cast' from type 'boost::beast::basic_flat_buffer<std::allocator<char> >::mutable_buffers_type' {aka 'boost::asio::mutable_buffer'} to type 'char*'
  117 |     auto* data = static_cast<char*>(buffer_.data());
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[heitbaum]

I did some further testing and using auto* data = static_cast<char*>(buffer_.data().data()); allows for successful compile, and matches the previous function and its return. But not sure if this is the corr3ct use/intention of this current code.

Previous buffer_cast code is:

/// Cast a non-modifiable buffer to a specified pointer to POD type.
template <typename PointerToPodType>
inline PointerToPodType buffer_cast(const mutable_buffer& b) noexcept
{
  return static_cast<PointerToPodType>(b.data());
}

So if the previous code is correct, then the fix is:

--- a/server/stream_session_ws.cpp
+++ b/server/stream_session_ws.cpp
@@ -114,7 +114,7 @@ void StreamSessionWebsocket::on_read_ws(beast::error_code ec, std::size_t bytes_
         return;
     }
 
-    auto* data = boost::asio::buffer_cast<char*>(buffer_.data());
+    auto* data = static_cast<char*>(buffer_.data().data());
     baseMessage_.deserialize(data);
     LOG(DEBUG, LOG_TAG) << "getNextMessage: " << baseMessage_.type << ", size: " << baseMessage_.size << ", id: " << baseMessage_.id
                         << ", refers: " << baseMessage_.refersTo << "\n";

I’m happy to raise the PR if this is the case.
This will be the final fix (now that #1310 is queued) to remove all boost 1.87.0 deprecated code.

[badaix]

Yes, this looks like the correct (original) solution to me:
auto* data = static_cast<char*>(buffer_.data().data());

[badaix]

Thanks, I've added the change here 6190041

[heitbaum]

Fixed