[gcc r14-6591] libstdc++: Simplify std::vprint_unicode for non-Windows targets

[gcc r14-6591] libstdc++: Simplify std::vprint_unicode for non-Windows targets

[Jonathan Wakely]

https://gcc.gnu.org/g:7d2e100058790e3407ae02b6db4a276957deaa4f

commit r14-6591-g7d2e100058790e3407ae02b6db4a276957deaa4f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Dec 15 12:24:26 2023 +0000

    libstdc++: Simplify std::vprint_unicode for non-Windows targets
    
    Since we don't need to do anything special to print Unicode on
    non-Windows targets, we might as well just use std::vprint_nonunicode to
    implement std::vprint_unicode. Removing the duplicated code should
    reduce code size in cases where those calls aren't inlined.
    
    Also use an RAII type for the unused case where a non-Windows target
    calls __open_terminal(streambuf*) and needs to fclose the result. This
    makes the code futureproof in case we ever start using the
    __write_terminal function for non-Windows targets.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/ostream (vprint_unicode) [_WIN32]: Use RAII guard.
            (vprint_unicode) [!_WIN32]: Just call vprint_nonunicode.
            * include/std/print (vprint_unicode) [!_WIN32]: Likewise.

Diff:
---
 libstdc++-v3/include/std/ostream | 31 +++++++++++++++++++++++--------
 libstdc++-v3/include/std/print   | 10 +++++++---
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/libstdc++-v3/include/std/ostream b/libstdc++-v3/include/std/ostream
index 0cac293e4d6..a9a7aefad71 100644
--- a/libstdc++-v3/include/std/ostream
+++ b/libstdc++-v3/include/std/ostream
@@ -906,6 +906,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   inline void
   vprint_unicode(ostream& __os, string_view __fmt, format_args __args)
   {
+#ifndef _WIN32
+    // For most targets we don't need to do anything special to write
+    // Unicode to a terminal.
+    std::vprint_nonunicode(__os, __fmt, __args);
+#else
     ostream::sentry __cerb(__os);
     if (__cerb)
       {
@@ -913,12 +918,27 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	std::vformat_to(__buf.out(), __os.getloc(), __fmt, __args);
 	auto __out = __buf.view();
 
-#ifdef _WIN32
 	void* __open_terminal(streambuf*);
 	error_code __write_to_terminal(void*, span<char>);
 	// If stream refers to a terminal, write a Unicode string to it.
 	if (auto __term = __open_terminal(__os.rdbuf()))
 	  {
+#ifndef _WIN32
+	    // For POSIX, __open_terminal(streambuf*) uses fdopen to open a
+	    // new file, so we would need to close it here. This code is not
+	    // actually compiled because it's inside an #ifdef _WIN32 group,
+	    // but just in case that changes in future ...
+	    struct _Guard
+	    {
+	      _Guard(void* __p) : _M_f((FILE*)__p) { }
+	      ~_Guard() { std::fclose(_M_f); }
+	      _Guard(_Guard&&) = delete;
+	      _Guard& operator=(_Guard&&) = delete;
+	      FILE* _M_f;
+	    };
+	    _Guard __g(__term);
+#endif
+
 	    ios_base::iostate __err = ios_base::goodbit;
 	    __try
 	      {
@@ -927,11 +947,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		else if (auto __e = __write_to_terminal(__term, __out))
 		  if (__e != std::make_error_code(errc::illegal_byte_sequence))
 		    __err = ios::badbit;
-#ifndef _WIN32
-		// __open_terminal(streambuf*) opens a new FILE with fdopen,
-		// so we need to close it here.
-		std::fclose((FILE*)__term);
-#endif
 	      }
 	    __catch(const __cxxabiv1::__forced_unwind&)
 	      {
@@ -945,9 +960,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	      __os.setstate(__err);
 	    return;
 	  }
-#endif
 
-	// Otherwise just insert the string as normal.
+	// Otherwise just insert the string as vprint_nonunicode does.
 	__try
 	  {
 	    std::__ostream_write(__os, __out.data(), __out.size());
@@ -960,6 +974,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	__catch(...)
 	  { __os._M_setstate(ios_base::badbit); }
       }
+#endif // _WIN32
   }
 
   template<typename... _Args>
diff --git a/libstdc++-v3/include/std/print b/libstdc++-v3/include/std/print
index e7099ab6fe3..bb029610d70 100644
--- a/libstdc++-v3/include/std/print
+++ b/libstdc++-v3/include/std/print
@@ -64,11 +64,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   inline void
   vprint_unicode(FILE* __stream, string_view __fmt, format_args __args)
   {
+#ifndef _WIN32
+    // For most targets we don't need to do anything special to write
+    // Unicode to a terminal.
+    std::vprint_nonunicode(__stream, __fmt, __args);
+#else
     __format::_Str_sink<char> __buf;
     std::vformat_to(__buf.out(), __fmt, __args);
     auto __out = __buf.view();
 
-#ifdef _WIN32
     void* __open_terminal(FILE*);
     error_code __write_to_terminal(void*, span<char>);
     // If stream refers to a terminal, write a native Unicode string to it.
@@ -88,11 +92,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  __e = error_code(errno, generic_category());
 	_GLIBCXX_THROW_OR_ABORT(system_error(__e, "std::vprint_unicode"));
       }
-#endif
 
-    // Otherwise just write the string to the file.
+    // Otherwise just write the string to the file as vprint_nonunicode does.
     if (std::fwrite(__out.data(), 1, __out.size(), __stream) != __out.size())
       __throw_system_error(EIO);
+#endif
   }
 
   template<typename... _Args>