A more lightweight O[U]StringConcatenation

...compared to a full-blown O[U]String, for temporary objects holding an
O[U]StringConcat result that can then be used as a std::[u16]string_view.

It's instructive to see how some invocations of operator ==, operator !=, and
O[U]StringBuffer::insert with an O[U]StringConcat argument required implicit
materialization of an O[U]String temporary, and how that expensive operation has
now been made explicit with the explicit O[U]StringConcatenation ctor.

(The additional operator == and operator != overloads are necessary because the
overloads taking two std::[u16]string_view parameters wouldn't even be found
here with ADL.  And the OUString-related ones would cause ambiguities in at
least sal/qa/rtl/strings/test_oustring_stringliterals.cxx built with
RTL_STRING_UNITTEST, so have simply been disabled for that special test-code
case.)

Change-Id: Id29799fa8da21a09ff9794cbc7cc9b366e6803b8
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/122890
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

3 files changed, 4 insertions, 4 deletions

diff --git a/chart2/qa/extras/chart2dump/chart2dump.cxx b/chart2/qa/extras/chart2dump/chart2dump.cxx
index fc3944f494e3..4d40c9cc3f8b 100644
--- a/chart2/qa/extras/chart2dump/chart2dump.cxx
+++ b/chart2/qa/extras/chart2dump/chart2dump.cxx
@@ -125,7 +125,7 @@ protected:
         {
             if (m_aReferenceFile.is_open())
                 m_aReferenceFile.close();
-            OString sReferenceFile = OUStringToOString(OUString(m_directories.getPathFromSrc(getReferenceDirName()) + sFileName), RTL_TEXTENCODING_UTF8);
+            OString sReferenceFile = OUStringToOString(OUStringConcatenation(m_directories.getPathFromSrc(getReferenceDirName()) + sFileName), RTL_TEXTENCODING_UTF8);
             m_aReferenceFile.open(sReferenceFile.getStr(), std::ios_base::in);
             CPPUNIT_ASSERT_MESSAGE(OString("Can't open reference file: " + sReferenceFile).getStr(), m_aReferenceFile.is_open());
         }
@@ -133,7 +133,7 @@ protected:
         {
             if (m_aDumpFile.is_open())
                 m_aDumpFile.close();
-            OString sDumpFile = OUStringToOString(OUString(m_directories.getPathFromSrc(getReferenceDirName()) + sFileName), RTL_TEXTENCODING_UTF8);
+            OString sDumpFile = OUStringToOString(OUStringConcatenation(m_directories.getPathFromSrc(getReferenceDirName()) + sFileName), RTL_TEXTENCODING_UTF8);
             m_aDumpFile.open(sDumpFile.getStr(), std::ios_base::out | std::ofstream::binary | std::ofstream::trunc);
             CPPUNIT_ASSERT_MESSAGE(OString("Can't open dump file: " + sDumpFile).getStr(), m_aDumpFile.is_open());
         }
diff --git a/chart2/source/tools/LogarithmicRegressionCurveCalculator.cxx b/chart2/source/tools/LogarithmicRegressionCurveCalculator.cxx
index c9e000e0243e..1e84ed81d42d 100644
--- a/chart2/source/tools/LogarithmicRegressionCurveCalculator.cxx
+++ b/chart2/source/tools/LogarithmicRegressionCurveCalculator.cxx
@@ -178,7 +178,7 @@ OUString LogarithmicRegressionCurveCalculator::ImplGetRepresentation(
         addStringToEquation( aBuf, nLineLength, aTmpBuf, pFormulaMaxWidth );
     }
 
-    if ( aBuf.toString() == (mYName + " = ") )
+    if ( aBuf.toString() == OUStringConcatenation(mYName + " = ") )
         aBuf.append( "0" );
 
     return aBuf.makeStringAndClear();
diff --git a/chart2/source/tools/PolynomialRegressionCurveCalculator.cxx b/chart2/source/tools/PolynomialRegressionCurveCalculator.cxx
index d6b22c1635f5..2c2e6be4b5bf 100644
--- a/chart2/source/tools/PolynomialRegressionCurveCalculator.cxx
+++ b/chart2/source/tools/PolynomialRegressionCurveCalculator.cxx
@@ -381,7 +381,7 @@ OUString PolynomialRegressionCurveCalculator::ImplGetRepresentation(
         }
         addStringToEquation( aBuf, nLineLength, aTmpBuf, pFormulaMaxWidth );
     }
-    if ( aBuf.toString() == ( mYName + " = ") )
+    if ( aBuf.toString() == OUStringConcatenation( mYName + " = ") )
         aBuf.append( "0" );
 
     return aBuf.makeStringAndClear();