Revert "Revert "Generalize OUStringLiteral1""

This reverts commit 5cba714b, now including a
workaround for <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53658> "internal
compiler error -- segmentation fault."

Change-Id: I31f6d9ddcb0b884134703df2b9dc1800ba0a84be

include/rtl/strbuf.hxx

@@ -170,10 +170,14 @@ public:
     template< typename T >
     OStringBuffer( T& literal, typename libreoffice_internal::ConstCharArrayDetector< T, libreoffice_internal::Dummy >::Type = libreoffice_internal::Dummy())
         : pData(NULL)
-        , nCapacity( libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1 + 16 )
-    {
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
-        rtl_string_newFromLiteral( &pData, literal, libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1, 16 );
+        , nCapacity( libreoffice_internal::ConstCharArrayDetector<T>::length + 16 )
+    {
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
+        rtl_string_newFromLiteral(
+            &pData,
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length, 16);
 #ifdef RTL_STRING_UNITTEST
         rtl_string_unittest_const_literal = true;
 #endif
@@ -453,8 +457,12 @@ public:
     typename libreoffice_internal::ConstCharArrayDetector< T, OStringBuffer& >::Type append( T& literal )
     {
         RTL_STRING_CONST_FUNCTION
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
-        rtl_stringbuffer_insert( &pData, &nCapacity, getLength(), literal, libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1 );
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
+        rtl_stringbuffer_insert(
+            &pData, &nCapacity, getLength(),
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length);
         return *this;
     }
 
@@ -708,8 +716,12 @@ public:
     typename libreoffice_internal::ConstCharArrayDetector< T, OStringBuffer& >::Type insert( sal_Int32 offset, T& literal )
     {
         RTL_STRING_CONST_FUNCTION
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
-        rtl_stringbuffer_insert( &pData, &nCapacity, offset, literal, libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1 );
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
+        rtl_stringbuffer_insert(
+            &pData, &nCapacity, offset,
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length);
         return *this;
     }
 

include/rtl/stringconcat.hxx

@@ -141,6 +141,19 @@ struct ToStringHelper< const char[ N ] >
     static const bool allowOUStringConcat = true;
     };
 
+#if defined LIBO_INTERNAL_ONLY
+template<char C> struct ToStringHelper<OUStringLiteral1_<C>> {
+    static int length(OUStringLiteral1_<C>) { return 1; }
+    static char * addData(char * buffer, OUStringLiteral1_<C> literal)
+    { return addDataHelper(buffer, &literal.c, 1); }
+    static sal_Unicode * addData(
+        sal_Unicode * buffer, OUStringLiteral1_<C> literal)
+    { return addDataLiteral(buffer, &literal.c, 1); }
+    static bool const allowOStringConcat = false;
+    static bool const allowOUStringConcat = true;
+};
+#endif
+
 /**
 @internal
 

include/rtl/stringutils.hxx

@@ -11,6 +11,10 @@
 #define INCLUDED_RTL_STRINGUTILS_HXX
 
 #include <sal/config.h>
+
+#include <cstddef>
+#include <cstring>
+
 #include <sal/types.h>
 
 // The unittest uses slightly different code to help check that the proper
@@ -29,6 +33,60 @@ namespace rtl
 #undef rtl
 #endif
 
+#if defined LIBO_INTERNAL_ONLY
+/// @cond INTERNAL
+
+/** A simple wrapper around an ASCII character literal.
+
+    Can be useful to pass a char constant with ASCII value into a
+    OUString-related function that is optimized for ASCII string literal
+    arguments.  That is, instead of
+
+      char const WILDCARD = '%';
+      ...
+      if (s[i] == WILDCARD) ...
+      ...
+      if (s.endsWith(OUString(WILDCARD))) ...
+
+    use
+
+      char const WILDCARD = '%';
+      ...
+      if (s[i] == WILDCARD) ...
+      ...
+      if (s.endsWith(OUStringLiteral1<WILDCARD>())) ...
+
+    to avoid creating a temporary OUString instance, and instead pick the
+    endsWith overload actually designed to take an argument of type
+    char const[N].
+
+    Instances of OUStringLiteral1 need to be const, as those literal-optimized
+    functions take the literal argument by non-const lvalue reference, for
+    technical reasons.  Except with MSVC, at least up to Visual Studio 2013:
+    For one, it fails to take that const-ness into account when trying to match
+    "OUStringLiteral1_<C> const" against T in a "T & literal" parameter of a
+    function template.  But for another, as a language extension, it allows to
+    bind non-const temporary OUStringLiteral1_ instances to non-const lvalue
+    references, but also with a warning that thus needs to be disabled.
+
+    @since LibreOffice 5.0
+*/
+template<char C> struct SAL_WARN_UNUSED OUStringLiteral1_ {
+    static_assert(
+        static_cast<unsigned char>(C) < 0x80,
+        "non-ASCII character in OUStringLiteral1");
+    char const c = C;
+};
+#if defined _MSC_VER && _MSC_VER <= 1800 // Visual Studio 2013
+template<char C> using OUStringLiteral1 = OUStringLiteral1_<C>;
+#pragma warning(disable: 4239)
+#else
+template<char C> using OUStringLiteral1 = OUStringLiteral1_<C> const;
+#endif
+
+/// @endcond
+#endif
+
 namespace libreoffice_internal
 {
 /*
@@ -102,13 +160,34 @@ struct ConstCharArrayDetector
 {
     static const bool ok = false;
 };
-template< int N, typename T >
+template< std::size_t N, typename T >
 struct ConstCharArrayDetector< const char[ N ], T >
 {
     typedef T Type;
-    static const int size = N;
+    static const std::size_t length = N - 1;
     static const bool ok = true;
+    static bool isValid(char const (& literal)[N])
+    { return std::strlen(literal) == length; }
+    static char const * toPointer(char const (& literal)[N]) { return literal; }
 };
+#if defined LIBO_INTERNAL_ONLY
+template<char C, typename T> struct ConstCharArrayDetector<
+#if defined __GNUC__ && __GNUC__ == 4 && __GNUC_MINOR__ <= 8 \
+        && !defined __clang__
+    OUStringLiteral1_<C> const,
+#else
+    OUStringLiteral1<C>,
+#endif
+    T>
+{
+    typedef T Type;
+    static const std::size_t length = 1;
+    static const bool ok = true;
+    static bool isValid(OUStringLiteral1_<C>) { return true; }
+    static char const * toPointer(OUStringLiteral1_<C> const & literal)
+    { return &literal.c; }
+};
+#endif
 
 // this one is used to rule out only const char[N]
 template< typename T >
@@ -137,6 +216,10 @@ template< int N >
 struct ExceptCharArrayDetector< const char[ N ] >
 {
 };
+#if defined LIBO_INTERNAL_ONLY && defined _MSC_VER && _MSC_VER <= 1800
+    // Visual Studio 2013
+template<char C> struct ExceptCharArrayDetector<OUStringLiteral1<C>> {};
+#endif
 
 template< typename T1, typename T2 = void >
 struct SalUnicodePtrDetector

include/rtl/ustrbuf.hxx

@@ -132,10 +132,14 @@ public:
     template< typename T >
     OUStringBuffer( T& literal, typename libreoffice_internal::ConstCharArrayDetector< T, libreoffice_internal::Dummy >::Type = libreoffice_internal::Dummy() )
         : pData(NULL)
-        , nCapacity( libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1 + 16 )
-    {
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
-        rtl_uString_newFromLiteral( &pData, literal, libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1, 16 );
+        , nCapacity( libreoffice_internal::ConstCharArrayDetector<T>::length + 16 )
+    {
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
+        rtl_uString_newFromLiteral(
+            &pData,
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length, 16);
 #ifdef RTL_STRING_UNITTEST
         rtl_string_unittest_const_literal = true;
 #endif
@@ -470,9 +474,12 @@ public:
     template< typename T >
     typename libreoffice_internal::ConstCharArrayDetector< T, OUStringBuffer& >::Type append( T& literal )
     {
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
-        rtl_uStringbuffer_insert_ascii( &pData, &nCapacity, getLength(), literal,
-            libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1 );
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
+        rtl_uStringbuffer_insert_ascii(
+            &pData, &nCapacity, getLength(),
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length);
         return *this;
     }
 
@@ -813,9 +820,12 @@ public:
     template< typename T >
     typename libreoffice_internal::ConstCharArrayDetector< T, OUStringBuffer& >::Type insert( sal_Int32 offset, T& literal )
     {
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
-        rtl_uStringbuffer_insert_ascii( &pData, &nCapacity, offset, literal,
-            libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1 );
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
+        rtl_uStringbuffer_insert_ascii(
+            &pData, &nCapacity, offset,
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length);
         return *this;
     }
 
@@ -1199,11 +1209,13 @@ public:
     template< typename T >
     typename libreoffice_internal::ConstCharArrayDetector< T, sal_Int32 >::Type indexOf( T& literal, sal_Int32 fromIndex = 0 ) const
     {
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
-        sal_Int32 ret = rtl_ustr_indexOfAscii_WithLength(
-            pData->buffer + fromIndex, pData->length - fromIndex, literal,
-            libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1);
-        return ret < 0 ? ret : ret + fromIndex;
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
+        sal_Int32 n = rtl_ustr_indexOfAscii_WithLength(
+            pData->buffer + fromIndex, pData->length - fromIndex,
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length);
+        return n < 0 ? n : n + fromIndex;
     }
 
     /**
@@ -1263,9 +1275,12 @@ public:
     template< typename T >
     typename libreoffice_internal::ConstCharArrayDetector< T, sal_Int32 >::Type lastIndexOf( T& literal ) const
     {
-        assert( strlen( literal ) == libreoffice_internal::ConstCharArrayDetector< T >::size - 1 );
+        assert(
+            libreoffice_internal::ConstCharArrayDetector<T>::isValid(literal));
         return rtl_ustr_lastIndexOfAscii_WithLength(
-            pData->buffer, pData->length, literal, libreoffice_internal::ConstCharArrayDetector< T, void >::size - 1);
+            pData->buffer, pData->length,
+            libreoffice_internal::ConstCharArrayDetector<T>::toPointer(literal),
+            libreoffice_internal::ConstCharArrayDetector<T>::length);
     }
 
     /**

sal/qa/rtl/strings/test_oustring_stringliterals.cxx

@@ -192,6 +192,20 @@ void test::oustring::StringLiterals::checkOUStringLiteral()
 
 void test::oustring::StringLiterals::checkOUStringLiteral1()
 {
+    auto l1 = rtlunittest::OUStringLiteral1<'A'>();
+    CPPUNIT_ASSERT_EQUAL('A', l1.c);
+
+    char const c2 = 'A';
+    auto l2 = rtlunittest::OUStringLiteral1<c2>();
+    CPPUNIT_ASSERT_EQUAL('A', l2.c);
+
+    // char c3 = 'A'; auto l3 = rtlunittest::OUStringLiteral1<c3>();
+
+    auto l4 = rtlunittest::OUStringLiteral1<sal_Unicode('A')>();
+    CPPUNIT_ASSERT_EQUAL('A', l4.c);
+
+    // auto l5 = rtlunittest::OUStringLiteral1<sal_Unicode(0x100)>();
+
     rtl::OUString s1;
     s1 = rtlunittest::OUStringLiteral1<'A'>();
     CPPUNIT_ASSERT_EQUAL(sal_Int32(1), s1.getLength());