From 4f85b6ec5964e2d9747f6743f9adc6ef1f951e4a Mon Sep 17 00:00:00 2001
From: Stephan Bergmann <sbergman@redhat.com>
Date: Wed, 5 May 2021 08:20:18 +0200
Subject: [PATCH] Adapt to "libstdc++: Implement LWG 1203 for rvalue iostreams"

<https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=aa475c4ac80733f85ba47b109fc1900f05e810e2>
towards GCC 12, so that now "the return type is the original rvalue stream type
not its base class."  (And which would thus have caused issues like

> sfx2/source/control/bindings.cxx:1323:19: error: dynamic_cast from rvalue to reference type '::std::ostringstream &' (aka 'basic_ostringstream<char> &')
>                 ? SAL_STREAM("File: " << pFile << " Line: " << nLine) : ""));
>                 ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/sal/log.hxx:198:6: note: expanded from macro 'SAL_STREAM'
>     (dynamic_cast< ::std::ostringstream & >(::std::ostringstream() << stream).str())
>      ^
> include/sal/log.hxx:341:20: note: expanded from macro 'SAL_INFO'
>         SAL_WHERE, stream)
>         ~~~~~~~~~~~^~~~~~~
> include/sal/log.hxx:155:68: note: expanded from macro 'SAL_DETAIL_LOG_STREAM'
>                 SAL_DETAIL_LOG_STREAM_PRIVATE_(level, area, where, stream); \
>                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> include/sal/log.hxx:133:45: note: expanded from macro 'SAL_DETAIL_LOG_STREAM_PRIVATE_'
>             ::sal::detail::StreamStart() << stream) == 1) \
>                                             ^~~~~~

now.  While the issue with old libstdc++ that originally prompted the
dynamic_cast was

> sfx2/source/control/bindings.cxx:1323:19: error: no member named 'str' in 'std::basic_ostream<char>'
>                 ? SAL_STREAM("File: " << pFile << " Line: " << nLine) : ""));
>                 ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/sal/log.hxx:194:40: note: expanded from macro 'SAL_STREAM'
>     (::std::ostringstream() << stream).str()
>                                        ^
> include/sal/log.hxx:336:20: note: expanded from macro 'SAL_INFO'
>         SAL_WHERE, stream)
>         ~~~~~~~~~~~^~~~~~~
> include/sal/log.hxx:155:68: note: expanded from macro 'SAL_DETAIL_LOG_STREAM'
>                 SAL_DETAIL_LOG_STREAM_PRIVATE_(level, area, where, stream); \
>                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> include/sal/log.hxx:133:45: note: expanded from macro 'SAL_DETAIL_LOG_STREAM_PRIVATE_'
>             ::sal::detail::StreamStart() << stream) == 1) \
>                                             ^~~~~~

.)

The libstdc++ macro _GLIBCXX_RELEASE is reportedly available since GCC 7.1.

Change-Id: I1ee6eabb66355c1f28b9d305cbd85bac50d6b0e1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115121
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

(cherry picked from commit 1f3dddd6f21d91c429190ae314dadeec409f35f4, plus
follow-up 95e26d3dce4f5a3b2d010d5ca47b4e450905a100 "tdf#142326: Adapt to
'libstdc++: Implement LWG 1203 for rvalue iostreams'")
Change-Id: I7c8fef25e15fcfa9b83924467dc86dc2957fbd7d
---
 include/sal/log.hxx | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/sal/log.hxx b/include/sal/log.hxx
index 6bb0d1b43d3d..a0fa902dbce6 100644
--- a/include/sal/log.hxx
+++ b/include/sal/log.hxx
@@ -186,7 +186,10 @@ inline char const * unwrapStream(SAL_UNUSED_PARAMETER StreamIgnore const &) {
 
     @since LibreOffice 3.5
 */
-#if defined _LIBCPP_VERSION || (defined _MSC_VER && _MSC_VER >= 1915)
+#if defined _LIBCPP_VERSION \
+    || (defined _GLIBCXX_RELEASE \
+        && (_GLIBCXX_RELEASE >= 12 || (_GLIBCXX_RELEASE == 11 && __GLIBCXX__ > 20210428))) \
+    || (defined _MSC_VER && _MSC_VER >= 1915)
 #define SAL_STREAM(stream) \
     (::std::ostringstream() << stream).str()
 #else
-- 
2.31.1