1 files changed, 43 insertions, 22 deletions

diff --git a/src/corelib/tools/qcollator_win.cpp b/src/corelib/tools/qcollator_win.cpp
index 5a838c1b50..9d81de882f 100644
--- a/src/corelib/tools/qcollator_win.cpp
+++ b/src/corelib/tools/qcollator_win.cpp
@@ -60,6 +60,8 @@ extern LCID qt_inIsoNametoLCID(const char *name);
 void QCollatorPrivate::init()
 {
     collator = 0;
+    if (isC())
+        return;
 
 #ifndef USE_COMPARESTRINGEX
     localeID = qt_inIsoNametoLCID(QLocalePrivate::get(locale)->bcp47Name().constData());
@@ -70,6 +72,8 @@ void QCollatorPrivate::init()
     if (caseSensitivity == Qt::CaseInsensitive)
         collator |= NORM_IGNORECASE;
 
+    // WINE does not support SORT_DIGITSASNUMBERS :-(
+    // (and its std::sort() crashes on bad comparisons, QTBUG-74209)
     if (numericMode)
         collator |= SORT_DIGITSASNUMBERS;
 
@@ -83,42 +87,57 @@ void QCollatorPrivate::cleanup()
 {
 }
 
-
-int QCollator::compare(const QChar *s1, int len1, const QChar *s2, int len2) const
+int QCollator::compare(QStringView s1, QStringView s2) const
 {
+    if (d->isC())
+        return s1.compare(s2, d->caseSensitivity);
+
     if (d->dirty)
         d->init();
 
     //* from Windows documentation *
-    // Returns one of the following values if successful. To maintain the C runtime convention of
-    // comparing strings, the value 2 can be subtracted from a nonzero return value. Then, the
-    // meaning of <0, ==0, and >0 is consistent with the C runtime.
+    // Returns one of the following values if successful. To maintain the C
+    // runtime convention of comparing strings, the value 2 can be subtracted
+    // from a nonzero return value. Then, the meaning of <0, ==0, and >0 is
+    // consistent with the C runtime.
+    // [...] The function returns 0 if it does not succeed.
+    // https://docs.microsoft.com/en-us/windows/desktop/api/stringapiset/nf-stringapiset-comparestringex#return-value
 
 #ifndef USE_COMPARESTRINGEX
-    return CompareString(d->localeID, d->collator,
-                         reinterpret_cast<const wchar_t*>(s1), len1,
-                         reinterpret_cast<const wchar_t*>(s2), len2) - 2;
+    const int ret = CompareString(d->localeID, d->collator,
+                                  reinterpret_cast<const wchar_t *>(s1.data()), s1.size(),
+                                  reinterpret_cast<const wchar_t *>(s2.data()), s2.size());
 #else
-    return CompareStringEx(LPCWSTR(d->localeName.utf16()), d->collator,
-                           reinterpret_cast<LPCWSTR>(s1), len1,
-                           reinterpret_cast<LPCWSTR>(s2), len2, NULL, NULL, 0) - 2;
+    const int ret = CompareStringEx(LPCWSTR(d->localeName.utf16()), d->collator,
+                                    reinterpret_cast<LPCWSTR>(s1.data()), s1.size(),
+                                    reinterpret_cast<LPCWSTR>(s2.data()), s2.size(),
+                                    nullptr, nullptr, 0);
 #endif
-}
-
-int QCollator::compare(const QString &str1, const QString &str2) const
-{
-    return compare(str1.constData(), str1.size(), str2.constData(), str2.size());
-}
-
-int QCollator::compare(const QStringRef &s1, const QStringRef &s2) const
-{
-    return compare(s1.constData(), s1.size(), s2.constData(), s2.size());
+    if (Q_LIKELY(ret))
+        return ret - 2;
+
+    switch (DWORD error = GetLastError()) {
+    case ERROR_INVALID_FLAGS:
+        qWarning("Unsupported flags (%d) used in QCollator", int(d->collator));
+        break;
+    case ERROR_INVALID_PARAMETER:
+        qWarning("Invalid parameter for QCollator::compare()");
+        break;
+    default:
+        qWarning("Failed (%ld) comparison in QCollator::compare()", long(error));
+        break;
+    }
+    // We have no idea what to return, so pretend we think they're equal.
+    // At least that way we'll be consistent if we get the same values swapped ...
+    return 0;
 }
 
 QCollatorSortKey QCollator::sortKey(const QString &string) const
 {
     if (d->dirty)
         d->init();
+    if (d->isC())
+        return QCollatorSortKey(new QCollatorSortKeyPrivate(string));
 
 #ifndef USE_COMPARESTRINGEX
     int size = LCMapStringW(d->localeID, LCMAP_SORTKEY | d->collator,
@@ -141,7 +160,9 @@ QCollatorSortKey QCollator::sortKey(const QString &string) const
                            NULL, NULL, 0);
 #endif
     if (finalSize == 0) {
-        qWarning() << "there were problems when generating the ::sortKey by LCMapStringW with error:" << GetLastError();
+        qWarning()
+            << "there were problems when generating the ::sortKey by LCMapStringW with error:"
+            << GetLastError();
     }
     return QCollatorSortKey(new QCollatorSortKeyPrivate(std::move(ret)));
 }