Goodbye O[U]StringView, welcome O[U]String::Concat

O[U]StringView had an odd mixture of uses.  For one, it was used like
std::[u16]string_view, for which directly using the latter std types is clearly
the better alternative.  For another, it was used in concatenation sequences,
when neither of the two leading terms were of our rtl string-related types.

For that second use case introduce O[U]String::Concat (as std::[u16]string_view
can obviously not be used, those not being one of our rtl string-related types).
Also, O[U]StringLiteral is occasionally used for this, but the planned changes
outlined in the 33ecd0d5c4fff9511a8436513936a3f7044a775a "Change OUStringLiteral
from char[] to char16_t[]" commit message will make that no longer work, so
O[U]String::Concat will be the preferred solution in such use cases going
forward, too.

O[U]StringView was also occasionally used to include O[U]StringBuffer values in
concatenation sequences, for which a more obvious alternative is to make
O[U]StringBuffer participate directly in the ToStringHelper/O[U]StringConcat
machinery.

Change-Id: I1f0e8d836796c9ae01c45f32c518be5f52976622
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/101586
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

24 files changed, 172 insertions, 97 deletions

diff --git a/codemaker/source/javamaker/javatype.cxx b/codemaker/source/javamaker/javatype.cxx
index f800d7365852..3fdf79abe300 100644
--- a/codemaker/source/javamaker/javatype.cxx
+++ b/codemaker/source/javamaker/javatype.cxx
@@ -379,7 +379,7 @@ void MethodDescriptor::addTypeParameter(OUString const & name) {
 }
 
 OString MethodDescriptor::getDescriptor() const {
-    return rtl::OStringView(m_descriptorStart) + m_descriptorEnd;
+    return m_descriptorStart + m_descriptorEnd;
 }
 
 
diff --git a/connectivity/source/drivers/postgresql/pq_preparedstatement.cxx b/connectivity/source/drivers/postgresql/pq_preparedstatement.cxx
index 30d386a6cd3c..5c827b3bc0b7 100644
--- a/connectivity/source/drivers/postgresql/pq_preparedstatement.cxx
+++ b/connectivity/source/drivers/postgresql/pq_preparedstatement.cxx
@@ -489,7 +489,7 @@ void PreparedStatement::setBytes(
             *this, OUString(), 1, Any() );
     }
     m_vars[parameterIndex-1]
-        = "'" + rtl::OStringView(reinterpret_cast<char *>(escapedString.get()), len -1) + "'";
+        = OString::Concat("'") + std::string_view(reinterpret_cast<char *>(escapedString.get()), len -1) + "'";
 }
 
 
diff --git a/i18npool/source/breakiterator/breakiterator_unicode.cxx b/i18npool/source/breakiterator/breakiterator_unicode.cxx
index 7c79b99ec028..bb8d7d9862aa 100644
--- a/i18npool/source/breakiterator/breakiterator_unicode.cxx
+++ b/i18npool/source/breakiterator/breakiterator_unicode.cxx
@@ -199,7 +199,7 @@ void BreakIterator_Unicode::loadICUBreakIterator(const css::lang::Locale& rLocal
                 }
 
                 status = U_ZERO_ERROR;
-                OString aUDName = rtl::OStringView(rule) + "_" + aLanguage;
+                OString aUDName = OString::Concat(rule) + "_" + aLanguage;
                 UDataMemory* pUData = udata_open("OpenOffice", "brk", aUDName.getStr(), &status);
                 if( U_SUCCESS(status) )
                     rbi = std::make_shared<OOoRuleBasedBreakIterator>( pUData, status);
diff --git a/i18npool/source/breakiterator/xdictionary.cxx b/i18npool/source/breakiterator/xdictionary.cxx
index a57a3b0d4a4d..e8d732c882b2 100644
--- a/i18npool/source/breakiterator/xdictionary.cxx
+++ b/i18npool/source/breakiterator/xdictionary.cxx
@@ -166,11 +166,11 @@ void xdictionary::initDictionaryData(const char *pLang)
 
 #ifdef SAL_DLLPREFIX
     OString sModuleName = // mostly "lib*.so" (with * == dict_zh)
-        SAL_DLLPREFIX
+        OString::Concat(SAL_DLLPREFIX "dict_") + pLang + SAL_DLLEXTENSION;
 #else
     OString sModuleName = // mostly "*.dll" (with * == dict_zh)
+        OString::Concat("dict_") + pLang + SAL_DLLEXTENSION;
 #endif
-        "dict_" + rtl::OStringView(pLang) + SAL_DLLEXTENSION;
     aEntry.mhModule = osl_loadModuleRelativeAscii( &thisModule, sModuleName.getStr(), SAL_LOADMODULE_DEFAULT );
     if( aEntry.mhModule ) {
         oslGenericFunction func;
diff --git a/i18npool/source/localedata/localedata.cxx b/i18npool/source/localedata/localedata.cxx
index d98a2e840460..61d04abbdfc0 100644
--- a/i18npool/source/localedata/localedata.cxx
+++ b/i18npool/source/localedata/localedata.cxx
@@ -550,7 +550,7 @@ oslGenericFunction lcl_LookupTableHelper::getFunctionSymbolByName(
                         {
                             (*pOutCachedItem).reset(new LocaleDataLookupTableItem( rCurrent ));
                             (*pOutCachedItem)->localeName = i.pLocale;
-                            OString sSymbolName = rtl::OStringView(pFunction) + "_" +
+                            OString sSymbolName = OString::Concat(pFunction) + "_" +
                                     (*pOutCachedItem)->localeName;
                             return (*pOutCachedItem)->module->getFunctionSymbol(
                                     sSymbolName.getStr());
@@ -563,10 +563,10 @@ oslGenericFunction lcl_LookupTableHelper::getFunctionSymbolByName(
             // Library not loaded, load it and add it to the list.
 #ifdef SAL_DLLPREFIX
             OString sModuleName =    // mostly "lib*.so"
-                SAL_DLLPREFIX + rtl::OStringView(i.pLib) + SAL_DLLEXTENSION;
+                OString::Concat(SAL_DLLPREFIX) + i.pLib + SAL_DLLEXTENSION;
 #else
             OString sModuleName =    // mostly "*.dll"
-                rtl::OStringView(i.pLib) + SAL_DLLEXTENSION;
+                OString::Concat(i.pLib) + SAL_DLLEXTENSION;
 #endif
             std::unique_ptr<osl::Module> module(new osl::Module());
             if ( module->loadRelative(&thisModule, sModuleName.getStr()) )
@@ -578,7 +578,7 @@ oslGenericFunction lcl_LookupTableHelper::getFunctionSymbolByName(
                 if( pOutCachedItem )
                 {
                     pOutCachedItem->reset(new LocaleDataLookupTableItem( maLookupTable.back() ));
-                    OString sSymbolName = rtl::OStringView(pFunction) + "_" + (*pOutCachedItem)->localeName;
+                    OString sSymbolName = OString::Concat(pFunction) + "_" + (*pOutCachedItem)->localeName;
                     return pTmpModule->getFunctionSymbol(sSymbolName.getStr());
                 }
                 else
@@ -1436,7 +1436,7 @@ oslGenericFunction LocaleDataImpl::getFunctionSymbol( const Locale& rLocale, con
 
     if (cachedItem && cachedItem->equals(rLocale))
     {
-        OString sSymbolName = rtl::OStringView(pFunction) + "_" +
+        OString sSymbolName = OString::Concat(pFunction) + "_" +
                 cachedItem->localeName;
         return cachedItem->module->getFunctionSymbol(sSymbolName.getStr());
     }
diff --git a/idlc/source/options.cxx b/idlc/source/options.cxx
index 2f2e3bb1e6f9..0ab0a9cc32d2 100644
--- a/idlc/source/options.cxx
+++ b/idlc/source/options.cxx
@@ -17,6 +17,9 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
+#include <sal/config.h>
+
+#include <string_view>
 
 #include <options.hxx>
 
@@ -285,7 +288,7 @@ bool Options::initOptions(std::vector< std::string > & rArgs)
         {
           return badOption("invalid", option);
         }
-        OString param = "-D" + rtl::OStringView((*first).c_str(), (*first).size());
+        OString param = OString::Concat("-D") + std::string_view((*first).c_str(), (*first).size());
         if (m_options.count("-D") > 0)
         {
           param = m_options["-D"] + " " + param;
diff --git a/include/rtl/strbuf.hxx b/include/rtl/strbuf.hxx
index 2a303ce998e6..e7e6cc01a2d0 100644
--- a/include/rtl/strbuf.hxx
+++ b/include/rtl/strbuf.hxx
@@ -1035,13 +1035,6 @@ public:
         *pInternalCapacity = &nCapacity;
     }
 
-#if defined LIBO_INTERNAL_ONLY
-    explicit operator OStringView() const
-    {
-        return OStringView(getStr(), getLength());
-    }
-#endif
-
 private:
     /**
         A pointer to the data structure which contains the data.
@@ -1054,6 +1047,18 @@ private:
     sal_Int32       nCapacity;
 };
 
+#if defined LIBO_INTERNAL_ONLY
+template<> struct ToStringHelper<OStringBuffer> {
+    static std::size_t length(OStringBuffer const & s) { return s.getLength(); }
+
+    static char * addData(char * buffer, OStringBuffer const & s) SAL_RETURNS_NONNULL
+    { return addDataHelper(buffer, s.getStr(), s.getLength()); }
+
+    static constexpr bool allowOStringConcat = true;
+    static constexpr bool allowOUStringConcat = false;
+};
+#endif
+
 }
 
 #ifdef RTL_STRING_UNITTEST
diff --git a/include/rtl/string.hxx b/include/rtl/string.hxx
index 35eccfc073c3..60485fbdfb96 100644
--- a/include/rtl/string.hxx
+++ b/include/rtl/string.hxx
@@ -1900,6 +1900,31 @@ public:
 #if defined LIBO_INTERNAL_ONLY
     operator std::string_view() const { return {getStr(), sal_uInt32(getLength())}; }
 #endif
+
+#if defined LIBO_INTERNAL_ONLY
+    // A wrapper for the first expression in an
+    //
+    //   OString::Concat(e1) + e2 + ...
+    //
+    // concatenation chain, when neither of the first two e1, e2 is one of our rtl string-related
+    // classes (so something like
+    //
+    //   OString s = "a" + (b ? std::string_view("c" : "dd");
+    //
+    // would not compile):
+    template<typename T> [[nodiscard]] static
+    typename std::enable_if_t<
+        ToStringHelper<T>::allowOStringConcat, OStringConcat<OStringConcatMarker, T>>
+    Concat(T const & value) { return OStringConcat<OStringConcatMarker, T>({}, value); }
+
+    // This overload is needed so that an argument of type 'char const[N]' ends up as
+    // 'OStringConcat<rtl::OStringConcatMarker, char const[N]>' rather than as
+    // 'OStringConcat<rtl::OStringConcatMarker, char[N]>':
+    template<typename T, std::size_t N> [[nodiscard]] static
+    typename std::enable_if_t<
+        ToStringHelper<T[N]>::allowOStringConcat, OStringConcat<OStringConcatMarker, T[N]>>
+    Concat(T (& value)[N]) { return OStringConcat<OStringConcatMarker, T[N]>({}, value); }
+#endif
 };
 
 /* ======================================================================= */
diff --git a/include/rtl/stringconcat.hxx b/include/rtl/stringconcat.hxx
index f5c9a4d33a52..e2cba5d86f0d 100644
--- a/include/rtl/stringconcat.hxx
+++ b/include/rtl/stringconcat.hxx
@@ -490,63 +490,52 @@ struct ToStringHelper< OUStringNumber< T > >
     static const bool allowOUStringConcat = true;
     };
 
-// Abstractions over null-terminated char and sal_Unicode strings that sometimes are needed in
-// concatenations of multiple such raw strings, as in
-//
-//   char const * s1, s2;
-//   OString s = OStringView(s1) + s2;
-//
-// (Providing specializations of ToStringHelper<std::string_view> and
-// ToStringHelper<std::u16string_view> would look dubious, as it would give meaning to expressions
-// like
-//
-//   std::string_view(s1) + s2
-//
-// that do not involve any user-defined types.)
-
-class OStringView {
-public:
-    explicit OStringView(char const * s): view_(s) {}
-    explicit OStringView(char const * s, size_t len): view_(s, len) {}
-
-    std::size_t length() const { return view_.length(); }
-
-    char const * data() const { return view_.data(); }
-
-private:
-    std::string_view view_;
+template<> struct ToStringHelper<std::string_view> {
+    static constexpr std::size_t length(std::string_view s) { return s.size(); }
+
+    static char * addData(char * buffer, std::string_view s) SAL_RETURNS_NONNULL
+    { return addDataHelper(buffer, s.data(), s.size()); }
+
+    static constexpr bool allowOStringConcat = true;
+    static constexpr bool allowOUStringConcat = false;
 };
 
-template<>
-struct ToStringHelper< OStringView >
-    {
-    static std::size_t length( const OStringView& v ) { return v.length(); }
-    static char* addData( char* buffer, const OStringView& v ) SAL_RETURNS_NONNULL { return addDataHelper( buffer, v.data(), v.length() ); }
-    static const bool allowOStringConcat = true;
-    static const bool allowOUStringConcat = false;
-    };
+template<> struct ToStringHelper<std::u16string_view> {
+    static constexpr std::size_t length(std::u16string_view s) { return s.size(); }
+
+    static sal_Unicode * addData(sal_Unicode * buffer, std::u16string_view s) SAL_RETURNS_NONNULL
+    { return addDataHelper(buffer, s.data(), s.size()); }
+
+    static constexpr bool allowOStringConcat = false;
+    static constexpr bool allowOUStringConcat = true;
+};
 
-class OUStringView {
-public:
-    explicit OUStringView(sal_Unicode const * s): view_(s) {}
-    explicit OUStringView(sal_Unicode const * s, size_t len): view_(s, len) {}
+// An internal marker class used by OString::Concat:
+struct OStringConcatMarker {};
 
-    std::size_t length() const { return view_.length(); }
+template<> struct ToStringHelper<OStringConcatMarker> {
+    static constexpr std::size_t length(OStringConcatMarker) { return 0; }
 
-    sal_Unicode const * data() const { return view_.data(); }
+    static constexpr char * addData(char * buffer, OStringConcatMarker) SAL_RETURNS_NONNULL
+    { return buffer; }
 
-private:
-    std::u16string_view view_;
+    static constexpr bool allowOStringConcat = true;
+    static constexpr bool allowOUStringConcat = false;
 };
 
-template<>
-struct ToStringHelper< OUStringView >
-    {
-    static std::size_t length( const OUStringView& v ) { return v.length(); }
-    static sal_Unicode* addData( sal_Unicode* buffer, const OUStringView& v ) SAL_RETURNS_NONNULL { return addDataHelper( buffer, v.data(), v.length() ); }
-    static const bool allowOStringConcat = false;
-    static const bool allowOUStringConcat = true;
-    };
+// An internal marker class used by OUString::Concat:
+struct OUStringConcatMarker {};
+
+template<> struct ToStringHelper<OUStringConcatMarker> {
+    static constexpr std::size_t length(OUStringConcatMarker) { return 0; }
+
+    static constexpr sal_Unicode * addData(sal_Unicode * buffer, OUStringConcatMarker)
+        SAL_RETURNS_NONNULL
+    { return buffer; }
+
+    static constexpr bool allowOStringConcat = false;
+    static constexpr bool allowOUStringConcat = true;
+};
 
 } // namespace
 
diff --git a/include/rtl/ustrbuf.hxx b/include/rtl/ustrbuf.hxx
index 9e8a586279b0..a4936b8fd186 100644
--- a/include/rtl/ustrbuf.hxx
+++ b/include/rtl/ustrbuf.hxx
@@ -1643,13 +1643,6 @@ public:
         return OUStringBuffer( pNew, count + 16 );
     }
 
-#if defined LIBO_INTERNAL_ONLY
-    explicit operator OUStringView() const
-    {
-        return OUStringView(getStr(), getLength());
-    }
-#endif
-
 private:
     OUStringBuffer( rtl_uString * value, const sal_Int32 capacity )
     {
@@ -1669,6 +1662,18 @@ private:
 };
 
 #if defined LIBO_INTERNAL_ONLY
+template<> struct ToStringHelper<OUStringBuffer> {
+    static std::size_t length(OUStringBuffer const & s) { return s.getLength(); }
+
+    static sal_Unicode * addData(sal_Unicode * buffer, OUStringBuffer const & s) SAL_RETURNS_NONNULL
+    { return addDataHelper(buffer, s.getStr(), s.getLength()); }
+
+    static constexpr bool allowOStringConcat = false;
+    static constexpr bool allowOUStringConcat = true;
+};
+#endif
+
+#if defined LIBO_INTERNAL_ONLY
     // Define this here to avoid circular includes
     inline OUString & OUString::operator+=( const OUStringBuffer & str ) &
     {
diff --git a/include/rtl/ustring.hxx b/include/rtl/ustring.hxx
index 229ed22aeb45..b99cf758ed8b 100644
--- a/include/rtl/ustring.hxx
+++ b/include/rtl/ustring.hxx
@@ -3693,6 +3693,31 @@ public:
     operator std::u16string_view() const { return {getStr(), sal_uInt32(getLength())}; }
 #endif
 
+#if defined LIBO_INTERNAL_ONLY
+    // A wrapper for the first expression in an
+    //
+    //   OUString::Concat(e1) + e2 + ...
+    //
+    // concatenation chain, when neither of the first two e1, e2 is one of our rtl string-related
+    // classes (so something like
+    //
+    //   OUString s = "a" + (b ? std::u16string_view(u"c" : u"dd");
+    //
+    // would not compile):
+    template<typename T> [[nodiscard]] static
+    typename std::enable_if_t<
+        ToStringHelper<T>::allowOUStringConcat, OUStringConcat<OUStringConcatMarker, T>>
+    Concat(T const & value) { return OUStringConcat<OUStringConcatMarker, T>({}, value); }
+
+    // This overload is needed so that an argument of type 'char const[N]' ends up as
+    // 'OUStringConcat<rtl::OUStringConcatMarker, char const[N]>' rather than as
+    // 'OUStringConcat<rtl::OUStringConcatMarker, char[N]>':
+    template<typename T, std::size_t N> [[nodiscard]] static
+    typename std::enable_if_t<
+        ToStringHelper<T[N]>::allowOUStringConcat, OUStringConcat<OUStringConcatMarker, T[N]>>
+    Concat(T (& value)[N]) { return OUStringConcat<OUStringConcatMarker, T[N]>({}, value); }
+#endif
+
 private:
     OUString & internalAppend( rtl_uString* pOtherData )
     {
diff --git a/oox/source/core/relationshandler.cxx b/oox/source/core/relationshandler.cxx
index af6481c3b576..90f3ebcef21c 100644
--- a/oox/source/core/relationshandler.cxx
+++ b/oox/source/core/relationshandler.cxx
@@ -19,6 +19,8 @@
 
 #include <sal/config.h>
 
+#include <string_view>
+
 #include <oox/core/relationshandler.hxx>
 
 #include <sal/log.hxx>
@@ -41,9 +43,9 @@ namespace {
 OUString lclGetRelationsPath( const OUString& rFragmentPath )
 {
     sal_Int32 nPathLen = ::std::max< sal_Int32 >( rFragmentPath.lastIndexOf( '/' ) + 1, 0 );
-    return rtl::OUStringView(rFragmentPath.getStr(), nPathLen ) +    // file path including slash
+    return OUString::Concat(std::u16string_view(rFragmentPath.getStr(), nPathLen )) +    // file path including slash
         "_rels/" +                                // additional '_rels/' path
-        rtl::OUStringView(rFragmentPath.getStr() + nPathLen) +  // file name after path
+        std::u16string_view(rFragmentPath.getStr() + nPathLen) +  // file name after path
         ".rels";                                 // '.rels' suffix
 }
 
diff --git a/opencl/source/openclwrapper.cxx b/opencl/source/openclwrapper.cxx
index aea040c73036..c7ac9525d620 100644
--- a/opencl/source/openclwrapper.cxx
+++ b/opencl/source/openclwrapper.cxx
@@ -185,7 +185,7 @@ OString createFileName(cl_device_id deviceId, const char* clFileName)
             platformVersion, nullptr);
 
     // create hash for deviceName + driver version + platform version
-    OString aString = rtl::OStringView(deviceName) + driverVersion + platformVersion;
+    OString aString = OString::Concat(deviceName) + driverVersion + platformVersion;
     OString aHash = generateMD5(aString.getStr(), aString.getLength());
 
     return getCacheFolder() + fileName + "-" + aHash + ".bin";
diff --git a/sal/qa/rtl/strings/test_ostring_concat.cxx b/sal/qa/rtl/strings/test_ostring_concat.cxx
index 1e7ae6da25e4..e5872654b58d 100644
--- a/sal/qa/rtl/strings/test_ostring_concat.cxx
+++ b/sal/qa/rtl/strings/test_ostring_concat.cxx
@@ -65,6 +65,8 @@ void test::ostring::StringConcat::checkConcat()
     CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OString, const char[ 4 ] > )), typeid( OString( "foo" ) + "bar" ));
     CPPUNIT_ASSERT_EQUAL( OString( "foobarbaz" ), OString( OString( "foo" ) + "bar" + "baz" ));
     CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringConcat< OString, const char[ 4 ] >, const char[ 4 ] > )), typeid( OString( "foo" ) + "bar" + "baz" ));
+    CPPUNIT_ASSERT_EQUAL( OString( "foobar" ), OString( OStringBuffer( "foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringBuffer, const char[ 4 ] > )), typeid( OStringBuffer( "foo" ) + "bar" ));
     CPPUNIT_ASSERT_EQUAL( OString( "foobar" ), OString( OStringLiteral( "foo" ) + "bar" ));
     CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringLiteral, const char[ 4 ] > )), typeid( OStringLiteral( "foo" ) + "bar" ));
     CPPUNIT_ASSERT_EQUAL( OString( "foobar" ), OString( OStringLiteral( "foo" ) + static_cast<const char*>("bar") ));
@@ -83,8 +85,16 @@ void test::ostring::StringConcat::checkConcat()
     CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OString, char* > )), typeid( OString( "foo" ) + d4 ));
     CPPUNIT_ASSERT_EQUAL( OString( "fooabc" ), OString( OString( "foo" ) + d4 ));
     CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OString, char* > )), typeid( OString( "foo" ) + d4 ));
-    CPPUNIT_ASSERT_EQUAL( OString( "fooabc" ), OString( rtl::OStringView( "foo" ) + d4 ));
-    CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< rtl::OStringView, char* > )), typeid( rtl::OStringView( "foo" ) + d4 ));
+    CPPUNIT_ASSERT_EQUAL( OString( "foobar" ), OString( OString::Concat( "foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringConcat< OStringConcatMarker, const char[ 4 ] >, const char[ 4 ] > )), typeid( OString::Concat( "foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OString( "xyzbar" ), OString( OString::Concat( d1 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringConcat< OStringConcatMarker, const char[ 4 ] >, const char[ 4 ] > )), typeid( OString::Concat( d1 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OString( "abcbar" ), OString( OString::Concat( d2 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringConcat< OStringConcatMarker, char[ 4 ] >, const char[ 4 ] > )), typeid( OString::Concat( d2 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OString( "xyzbar" ), OString( OString::Concat( d3 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringConcat< OStringConcatMarker, const char* >, const char[ 4 ] > )), typeid( OString::Concat( d3 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OString( "abcbar" ), OString( OString::Concat( d4 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OStringConcat< OStringConcatMarker, char* >, const char[ 4 ] > )), typeid( OString::Concat( d4 ) + "bar" ));
 
     CPPUNIT_ASSERT_EQUAL( OString( "num10" ), OString( OString( "num" ) + OString::number( 10 )));
     CPPUNIT_ASSERT_EQUAL(( typeid( OStringConcat< OString, OStringNumber< int > > )), typeid( OString( "num" ) + OString::number( 10 )));
@@ -155,11 +165,10 @@ void test::ostring::StringConcat::checkAppend()
 void test::ostring::StringConcat::checkInvalid()
 {
     CPPUNIT_ASSERT( !INVALID_CONCAT( OString() + OString()));
-    CPPUNIT_ASSERT( INVALID_CONCAT( OString( "a" ) + OStringBuffer( "b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OString( "a" ) + OUString( "b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OString( "a" ) + OUStringBuffer( "b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OString( "a" ) + OUStringLiteral( u"b" )));
-    CPPUNIT_ASSERT( INVALID_CONCAT( OString( "a" ) + rtl::OUStringView( u"b" )));
+    CPPUNIT_ASSERT( INVALID_CONCAT( OString( "a" ) + OUString::Concat( u"b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OString( "a" ) + 1 ));
     rtl_String* rs = nullptr;
     rtl_uString* rus = nullptr;
diff --git a/sal/qa/rtl/strings/test_oustring_concat.cxx b/sal/qa/rtl/strings/test_oustring_concat.cxx
index 4ffe20966a09..5203d0b6b5f0 100644
--- a/sal/qa/rtl/strings/test_oustring_concat.cxx
+++ b/sal/qa/rtl/strings/test_oustring_concat.cxx
@@ -66,6 +66,8 @@ void test::oustring::StringConcat::checkConcat()
     CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUString, const char[ 4 ] > )), typeid( OUString( "foo" ) + "bar" ));
     CPPUNIT_ASSERT_EQUAL( OUString( "foobarbaz" ), OUString( OUString( "foo" ) + "bar" + "baz" ));
     CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringConcat< OUString, const char[ 4 ] >, const char[ 4 ] > )), typeid( OUString( "foo" ) + "bar" + "baz" ));
+    CPPUNIT_ASSERT_EQUAL( OUString( "foobar" ), OUString( OUStringBuffer( "foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringBuffer, const char[ 4 ] > )), typeid( OUStringBuffer( "foo" ) + "bar" ));
     CPPUNIT_ASSERT_EQUAL( OUString( "foobar" ), OUString( OUStringLiteral( u"foo" ) + "bar" ));
     CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringLiteral, const char[ 4 ] > )), typeid( OUStringLiteral( u"foo" ) + "bar" ));
     const char d1[] = "xyz";
@@ -74,8 +76,17 @@ void test::oustring::StringConcat::checkConcat()
     const sal_Unicode* d2 = u"xyz";
     CPPUNIT_ASSERT_EQUAL( OUString( "fooxyz" ), OUString( OUString( "foo" ) + d2 ));
     CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUString, const sal_Unicode* > )), typeid( OUString( "foo" ) + d2 ));
-    CPPUNIT_ASSERT_EQUAL( OUString( "fooxyz" ), OUString( rtl::OUStringView( u"foo" ) + d2 ));
-    CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< rtl::OUStringView, const sal_Unicode* > )), typeid( rtl::OUStringView( u"foo" ) + d2 ));
+    const sal_Unicode d3[] = u"xyz";
+    CPPUNIT_ASSERT_EQUAL( OUString( "foobar" ), OUString( OUString::Concat( "foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringConcat< rtl::OUStringConcatMarker, const char[ 4 ] >, const char[ 4 ] > )), typeid( OUString::Concat( "foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OUString( "xyzbar" ), OUString( OUString::Concat( d1 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringConcat< rtl::OUStringConcatMarker, const char[ 4 ] >, const char[ 4 ] > )), typeid( OUString::Concat( d1 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OUString( "foobar" ), OUString( OUString::Concat( u"foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringConcat< rtl::OUStringConcatMarker, const sal_Unicode[ 4 ] >, const char[ 4 ] > )), typeid( OUString::Concat( u"foo" ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OUString( "xyzbar" ), OUString( OUString::Concat( d2 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringConcat< rtl::OUStringConcatMarker, const sal_Unicode* >, const char[ 4 ] > )), typeid( OUString::Concat( d2 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL( OUString( "xyzbar" ), OUString( OUString::Concat( d3 ) + "bar" ));
+    CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUStringConcat< rtl::OUStringConcatMarker, const sal_Unicode[ 4 ] >, const char[ 4 ] > )), typeid( OUString::Concat( d3 ) + "bar" ));
 
     CPPUNIT_ASSERT_EQUAL( OUString( "num10" ), OUString( OUString( "num" ) + OUString::number( 10 )));
     CPPUNIT_ASSERT_EQUAL(( typeid( OUStringConcat< OUString, OUStringNumber< int > > )), typeid( OUString( "num" ) + OUString::number( 10 )));
@@ -164,7 +175,6 @@ void test::oustring::StringConcat::checkAppend()
 void test::oustring::StringConcat::checkInvalid()
 {
     CPPUNIT_ASSERT( !INVALID_CONCAT( OUString() + OUString()));
-    CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + OUStringBuffer( "b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + OString( "b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + OStringBuffer( "b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + static_cast<const char*>("b") ));
@@ -172,7 +182,7 @@ void test::oustring::StringConcat::checkInvalid()
     CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + d ));
     CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + static_cast<char*>(d) ));
     CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + OStringLiteral( "b" )));
-    CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + rtl::OStringView( "b" )));
+    CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + OString::Concat( "b" )));
     CPPUNIT_ASSERT( INVALID_CONCAT( OUString( "a" ) + 1 ));
     rtl_String* rs = nullptr;
     rtl_uString* rus = nullptr;
diff --git a/sdext/source/pdfimport/sax/emitcontext.cxx b/sdext/source/pdfimport/sax/emitcontext.cxx
index 80c459c7d82e..a923488d688d 100644
--- a/sdext/source/pdfimport/sax/emitcontext.cxx
+++ b/sdext/source/pdfimport/sax/emitcontext.cxx
@@ -163,7 +163,7 @@ void SaxEmitter::endTag( const char* pTag )
     for( int i = 0; i < nIndent; i++ )
         pStream->write( "    ", 4, nWritten );
 
-    OString aBuf = "</" + rtl::OStringView(pTag) + ">\n";
+    OString aBuf = OString::Concat("</") + pTag + ">\n";
     pStream->write( aBuf.getStr(), aBuf.getLength(), nWritten );
     nIndent--;
 #endif
diff --git a/sfx2/source/appl/appuno.cxx b/sfx2/source/appl/appuno.cxx
index da8d333c935b..559cadd8f534 100644
--- a/sfx2/source/appl/appuno.cxx
+++ b/sfx2/source/appl/appuno.cxx
@@ -242,7 +242,7 @@ void TransformParameters( sal_uInt16 nSlotId, const uno::Sequence<beans::Propert
                 for ( nSub=0; nSub<nSubCount; nSub++ )
                 {
                     // search sub item by name
-                    OString aStr = rtl::OStringView(pSlot->pUnoName) + "." + pType->aAttrib[nSub].pName;
+                    OString aStr = OString::Concat(pSlot->pUnoName) + "." + pType->aAttrib[nSub].pName;
                     if ( rPropValue.Name.equalsAsciiL(aStr.getStr(), aStr.getLength()) )
                     {
                         sal_uInt8 nSubId = static_cast<sal_uInt8>(static_cast<sal_Int8>(pType->aAttrib[nSub].nAID));
@@ -345,7 +345,7 @@ void TransformParameters( sal_uInt16 nSlotId, const uno::Sequence<beans::Propert
                     for ( sal_uInt16 nSub=0; nSub<nSubCount; nSub++ )
                     {
                         // search sub item by name
-                        OString aStr = rtl::OStringView(rArg.pName) + "." + pType->aAttrib[nSub].pName;
+                        OString aStr = OString::Concat(rArg.pName) + "." + pType->aAttrib[nSub].pName;
                         if ( rProp.Name.equalsAsciiL(aStr.getStr(), aStr.getLength()) )
                         {
                             // at least one member found ...
diff --git a/stoc/source/uriproc/UriSchemeParser_vndDOTsunDOTstarDOTscript.cxx b/stoc/source/uriproc/UriSchemeParser_vndDOTsunDOTstarDOTscript.cxx
index 6f8624d270fb..960ecbcd16a8 100644
--- a/stoc/source/uriproc/UriSchemeParser_vndDOTsunDOTstarDOTscript.cxx
+++ b/stoc/source/uriproc/UriSchemeParser_vndDOTsunDOTstarDOTscript.cxx
@@ -284,7 +284,7 @@ void SAL_CALL UrlReference::setName(OUString const & name)
 
     auto tmp = std::u16string_view(m_base.m_path).substr(i);
     m_base.m_path = encodeNameOrParamFragment(name) +
-        rtl::OUStringView(tmp.data(), tmp.length());
+        std::u16string_view(tmp.data(), tmp.length());
 }
 
 sal_Bool UrlReference::hasParameter(OUString const & key)
diff --git a/svtools/source/svhtml/htmlout.cxx b/svtools/source/svhtml/htmlout.cxx
index ce43e2dd9cce..20d06954fdc7 100644
--- a/svtools/source/svhtml/htmlout.cxx
+++ b/svtools/source/svhtml/htmlout.cxx
@@ -923,7 +923,7 @@ SvStream& HTMLOutFuncs::Out_Events( SvStream& rStrm,
 
             if( pStr )
             {
-                OString sOut = " " + rtl::OStringView(pStr) + "=\"";
+                OString sOut = OString::Concat(" ") + pStr + "=\"";
                 rStrm.WriteOString( sOut );
 
                 Out_String( rStrm, pMacro->GetMacName(), eDestEnc, pNonConvertableChars ).WriteChar( '\"' );
diff --git a/sw/source/filter/html/htmlftn.cxx b/sw/source/filter/html/htmlftn.cxx
index 5787ed80bc38..cec1d3df6326 100644
--- a/sw/source/filter/html/htmlftn.cxx
+++ b/sw/source/filter/html/htmlftn.cxx
@@ -505,7 +505,7 @@ static void lcl_html_outFootEndNoteInfo( Writer& rWrt, OUString const *pParts,
     rHTMLWrt.OutNewLine();
     OString sOut =
         "<" + rHTMLWrt.GetNamespace() + OOO_STRING_SVTOOLS_HTML_meta " "
-        OOO_STRING_SVTOOLS_HTML_O_name "=\"" + rtl::OStringView(pName) +
+        OOO_STRING_SVTOOLS_HTML_O_name "=\"" + pName +
         "\" " OOO_STRING_SVTOOLS_HTML_O_content "=\"";
     rWrt.Strm().WriteOString( sOut );
     HTMLOutFuncs::Out_String( rWrt.Strm(), aContent.makeStringAndClear(), rHTMLWrt.m_eDestEnc, &rHTMLWrt.m_aNonConvertableCharacters );
diff --git a/tools/source/fsys/urlobj.cxx b/tools/source/fsys/urlobj.cxx
index 2478a2bd5d55..d52edb1d2f2a 100644
--- a/tools/source/fsys/urlobj.cxx
+++ b/tools/source/fsys/urlobj.cxx
@@ -39,6 +39,7 @@
 #include <cassert>
 #include <limits>
 #include <memory>
+#include <string_view>
 
 #include <string.h>
 
@@ -4198,8 +4199,8 @@ bool INetURLObject::removeExtension(sal_Int32 nIndex, bool bIgnoreFinalSlash)
         return true;
 
     OUString aNewPath =
-        rtl::OUStringView(pPathBegin, pExtension - pPathBegin) +
-        rtl::OUStringView(p, pPathEnd - p);
+        OUString::Concat(std::u16string_view(pPathBegin, pExtension - pPathBegin)) +
+        std::u16string_view(p, pPathEnd - p);
 
     return setPath(aNewPath, EncodeMechanism::NotCanonical, RTL_TEXTENCODING_UTF8);
 }
@@ -4226,7 +4227,8 @@ bool INetURLObject::setFinalSlash()
     if (pPathEnd > pPathBegin && pPathEnd[-1] == '/')
         return true;
 
-    OUString aNewPath = rtl::OUStringView(pPathBegin, pPathEnd - pPathBegin) + "/";
+    OUString aNewPath
+        = OUString::Concat(std::u16string_view(pPathBegin, pPathEnd - pPathBegin)) + "/";
 
     return setPath(aNewPath, EncodeMechanism::NotCanonical, RTL_TEXTENCODING_UTF8);
 }
diff --git a/ucb/source/ucp/webdav/SerfPutReqProcImpl.cxx b/ucb/source/ucp/webdav/SerfPutReqProcImpl.cxx
index 466f7a10cacb..6641016aec62 100644
--- a/ucb/source/ucp/webdav/SerfPutReqProcImpl.cxx
+++ b/ucb/source/ucp/webdav/SerfPutReqProcImpl.cxx
@@ -67,7 +67,7 @@ serf_bucket_t * SerfPutReqProcImpl::createSerfRequestBucket( serf_request_t * in
     setRequestHeaders( hdrs_bkt );
 
     // 'If' header with token, so that we can save document locked by us
-    const OString sIfHeader( "<" + rtl::OStringView(getPathStr()) + "> (<" + OUStringToOString(
+    const OString sIfHeader( OString::Concat("<") + getPathStr() + "> (<" + OUStringToOString(
                 msToken, RTL_TEXTENCODING_UTF8) + ">)" );
     serf_bucket_headers_set( hdrs_bkt, "If", sIfHeader.getStr() );
 
diff --git a/vcl/source/gdi/pdfwriter_impl.cxx b/vcl/source/gdi/pdfwriter_impl.cxx
index c879c9143858..4d2e94540614 100644
--- a/vcl/source/gdi/pdfwriter_impl.cxx
+++ b/vcl/source/gdi/pdfwriter_impl.cxx
@@ -1571,7 +1571,7 @@ void PDFWriterImpl::appendLiteralStringEncrypt( const OUString& rInString, const
 
 void PDFWriterImpl::emitComment( const char* pComment )
 {
-    OString aLine = "% " + rtl::OStringView(pComment) + "\n";
+    OString aLine = OString::Concat("% ") + pComment + "\n";
     writeBuffer( aLine.getStr(), aLine.getLength() );
 }
 
diff --git a/vcl/source/opengl/OpenGLHelper.cxx b/vcl/source/opengl/OpenGLHelper.cxx
index 64a470fe5f63..fc5cc3703b7a 100644
--- a/vcl/source/opengl/OpenGLHelper.cxx
+++ b/vcl/source/opengl/OpenGLHelper.cxx
@@ -213,7 +213,7 @@ namespace
             OUStringToOString(aInfo.GetDriverVersion(), RTL_TEXTENCODING_UTF8) +
             OString::number(DriverBlocklist::GetWindowsVersion());
 #else
-        return rtl::OStringView(reinterpret_cast<const char*>(glGetString(GL_VENDOR))) +
+        return OString::Concat(reinterpret_cast<const char*>(glGetString(GL_VENDOR))) +
             reinterpret_cast<const char*>(glGetString(GL_RENDERER)) +
             reinterpret_cast<const char*>(glGetString(GL_VERSION));
 #endif