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>

2 files changed, 42 insertions, 8 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
diff --git a/include/rtl/ustring.hxx b/include/rtl/ustring.hxx
index 1731bb905c76..24005b22333d 100644
--- a/include/rtl/ustring.hxx
+++ b/include/rtl/ustring.hxx
@@ -56,6 +56,8 @@ extern bool rtl_string_unittest_invalid_conversion;
 namespace rtl
 {
 
+class OUStringBuffer;
+
 #ifdef RTL_STRING_UNITTEST
 #undef rtl
 #endif
@@ -516,6 +518,18 @@ public:
     }
 #endif
 
+#if defined LIBO_INTERNAL_ONLY
+    /**
+      Append the contents of an OUStringBuffer to this string.
+
+      @param    str         an OUStringBuffer.
+
+      @exception std::bad_alloc is thrown if an out-of-memory condition occurs
+      @since LibreOffice 6.2
+    */
+    inline OUString & operator+=( const OUStringBuffer & str ) &;
+#endif
+
     /**
       Append a string to this string.
 
@@ -528,14 +542,7 @@ public:
         &
 #endif
     {
-        rtl_uString* pNewData = NULL;
-        rtl_uString_newConcat( &pNewData, pData, str.pData );
-        if (pNewData == NULL) {
-            throw std::bad_alloc();
-        }
-        rtl_uString_assign(&pData, pNewData);
-        rtl_uString_release(pNewData);
-        return *this;
+        return internalAppend(str.pData);
     }
 #if defined LIBO_INTERNAL_ONLY
     void operator+=(OUString const &) && = delete;
@@ -3539,6 +3546,20 @@ public:
         rtl_uString_newFromAscii( &pNew, value );
         return OUString( pNew, SAL_NO_ACQUIRE );
     }
+
+private:
+    OUString & internalAppend( rtl_uString* pOtherData )
+    {
+        rtl_uString* pNewData = NULL;
+        rtl_uString_newConcat( &pNewData, pData, pOtherData );
+        if (pNewData == NULL) {
+            throw std::bad_alloc();
+        }
+        rtl_uString_assign(&pData, pNewData);
+        rtl_uString_release(pNewData);
+        return *this;
+    }
+
 };
 
 #if defined LIBO_INTERNAL_ONLY