add operator+=(OUStringBuffer) method to OUString

to reduce needless object creation and copying some more

And fix what looks like a bug in CSS hex color parsing at line
609 in sw/../parcss1.cxx that has been there since
commit 7b0b5cdfeed656b279bc32cd929630d5fc25878b "initial import"

Change-Id: Ibad42b23721a56493bd1edcd7165e6104494a5c3
Reviewed-on: https://gerrit.libreoffice.org/58357
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/rtl/ustrbuf.hxx b/include/rtl/ustrbuf.hxx
index 1a40eeee8832..5f696bff906d 100644
--- a/include/rtl/ustrbuf.hxx
+++ b/include/rtl/ustrbuf.hxx
@@ -59,6 +59,7 @@ namespace rtl
  */
 class SAL_WARN_UNUSED OUStringBuffer
 {
+friend class OUString;
 public:
     /**
         Constructs a string buffer with no characters in it and an
@@ -1615,6 +1616,18 @@ private:
     sal_Int32       nCapacity;
 };
 
+#if defined LIBO_INTERNAL_ONLY
+    // Define this here to avoid circular includes
+    inline OUString & OUString::operator+=( const OUStringBuffer & str ) &
+    {
+        // Call operator= if this is empty, otherwise rtl_uString_newConcat will attempt to
+        // acquire() the str.pData buffer, which is part of the OUStringBuffer mutable state.
+        if (isEmpty())
+            return operator=(str.toString());
+        else
+            return internalAppend(str.pData);
+    }
+#endif
 }
 
 #ifdef RTL_STRING_UNITTEST