QByteArrayList: fix narrowing in join() implementations [2/2]

We forgot to adjust the interface and implementation of join() to the
int → qsizetype change in Qt 6.

This part of the two-part patch fixes things in a non-forwards-BC way,
so it can't be picked into released versions. The forwards-BC part is
in the first patch of the series.

We can't just replace the int seplen with qsizetype, because qsizetype
is an alias to int on 32-bit platforms. So, pass the separator by
QByteArrayView.

[ChangeLog][QtCore][QByteArrayList] Fixed a bug when calling join()
with separators of length > INTMAX.

Change-Id: I2ccc61de1c8901ac5504aea1ebd895d12dbcb064
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

3 files changed, 16 insertions, 7 deletions

diff --git a/src/corelib/compat/removed_api.cpp b/src/corelib/compat/removed_api.cpp
index b2e758d2ca..8d5bfb44a7 100644
--- a/src/corelib/compat/removed_api.cpp
+++ b/src/corelib/compat/removed_api.cpp
@@ -89,6 +89,13 @@ QUuid QUuid::fromRfc4122(const QByteArray &bytes)
     return fromRfc4122(qToByteArrayViewIgnoringNull(bytes));
 }
 
+#include "qbytearraylist.h"
+
+QByteArray QtPrivate::QByteArrayList_join(const QByteArrayList *that, const char *sep, int seplen)
+{
+    return QByteArrayList_join(that, {sep, seplen});
+}
+
 // #include <qotherheader.h>
 // // implement removed functions from qotherheader.h
 
diff --git a/src/corelib/text/qbytearraylist.cpp b/src/corelib/text/qbytearraylist.cpp
index 44a0f6be95..cd77cd905a 100644
--- a/src/corelib/text/qbytearraylist.cpp
+++ b/src/corelib/text/qbytearraylist.cpp
@@ -144,15 +144,15 @@ static qsizetype QByteArrayList_joinedSize(const QByteArrayList *that, qsizetype
     return totalLength;
 }
 
-QByteArray QtPrivate::QByteArrayList_join(const QByteArrayList *that, const char *sep, int seplen)
+QByteArray QtPrivate::QByteArrayList_join(const QByteArrayList *that, QByteArrayView sep)
 {
     QByteArray res;
-    if (const qsizetype joinedSize = QByteArrayList_joinedSize(that, seplen))
+    if (const qsizetype joinedSize = QByteArrayList_joinedSize(that, sep.size()))
         res.reserve(joinedSize); // don't call reserve(0) - it allocates one byte for the NUL
     const qsizetype size = that->size();
     for (qsizetype i = 0; i < size; ++i) {
         if (i)
-            res.append(sep, seplen);
+            res.append(sep);
         res += that->at(i);
     }
     return res;
diff --git a/src/corelib/text/qbytearraylist.h b/src/corelib/text/qbytearraylist.h
index 83e43e817d..890cbcef2d 100644
--- a/src/corelib/text/qbytearraylist.h
+++ b/src/corelib/text/qbytearraylist.h
@@ -58,7 +58,10 @@ typedef QMutableListIterator<QByteArray> QMutableByteArrayListIterator;
 #ifndef Q_CLANG_QDOC
 
 namespace QtPrivate {
+#if QT_REMOVED_SINCE(6, 3)
     QByteArray Q_CORE_EXPORT QByteArrayList_join(const QByteArrayList *that, const char *separator, int separatorLength);
+#endif
+    QByteArray Q_CORE_EXPORT QByteArrayList_join(const QByteArrayList *that, QByteArrayView separator);
 }
 #endif
 
@@ -78,17 +81,16 @@ public:
     using QListSpecialMethodsBase<QByteArray>::contains;
 
     inline QByteArray join() const
-    { return QtPrivate::QByteArrayList_join(self(), nullptr, 0); }
+    { return join(QByteArrayView{}); }
     inline QByteArray join(QByteArrayView sep) const // ### Qt 7: merge with the () overload
     {
-        Q_ASSERT(sep.size() <= (std::numeric_limits<int>::max)());
-        return QtPrivate::QByteArrayList_join(self(), sep.data(), sep.size());
+        return QtPrivate::QByteArrayList_join(self(), sep);
     }
     Q_WEAK_OVERLOAD
     inline QByteArray join(const QByteArray &sep) const
     { return join(QByteArrayView{sep}); }
     inline QByteArray join(char sep) const
-    { return QtPrivate::QByteArrayList_join(self(), &sep, 1); }
+    { return join({&sep, 1}); }
 };
 
 QT_END_NAMESPACE