Add back QByteArray's relational operators taking QString

QString still has the overloads of relational operators taking
QByteArray. Add back QByteArray's relational operators taking
QString for symmetry. See also the comments of
d7ccd8cb4565c8643b158891c9de3187c1586dc9 for more details.

[ChangeLog][EDITORIAL] Remove the changelog about QString/QByteArray
operators being removed. They're back.

Change-Id: I22c95e727285cf8a5ef79b3a4f9d45cb66319252
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 105 insertions, 0 deletions

diff --git a/src/corelib/text/qbytearray.cpp b/src/corelib/text/qbytearray.cpp
index bcbbdc234f..041fb06554 100644
--- a/src/corelib/text/qbytearray.cpp
+++ b/src/corelib/text/qbytearray.cpp
@@ -2991,6 +2991,90 @@ QDataStream &operator>>(QDataStream &in, QByteArray &ba)
 }
 #endif // QT_NO_DATASTREAM
 
+/*! \fn bool QByteArray::operator==(const QString &str) const
+
+    Returns \c true if this byte array is equal to the UTF-8 encoding of \a str;
+    otherwise returns \c false.
+
+    The comparison is case sensitive.
+
+    You can disable this operator by defining \c
+    QT_NO_CAST_FROM_ASCII when you compile your applications. You
+    then need to call QString::fromUtf8(), QString::fromLatin1(),
+    or QString::fromLocal8Bit() explicitly if you want to convert the byte
+    array to a QString before doing the comparison.
+*/
+
+/*! \fn bool QByteArray::operator!=(const QString &str) const
+
+    Returns \c true if this byte array is not equal to the UTF-8 encoding of \a
+    str; otherwise returns \c false.
+
+    The comparison is case sensitive.
+
+    You can disable this operator by defining \c
+    QT_NO_CAST_FROM_ASCII when you compile your applications. You
+    then need to call QString::fromUtf8(), QString::fromLatin1(),
+    or QString::fromLocal8Bit() explicitly if you want to convert the byte
+    array to a QString before doing the comparison.
+*/
+
+/*! \fn bool QByteArray::operator<(const QString &str) const
+
+    Returns \c true if this byte array is lexically less than the UTF-8 encoding
+    of \a str; otherwise returns \c false.
+
+    The comparison is case sensitive.
+
+    You can disable this operator by defining \c
+    QT_NO_CAST_FROM_ASCII when you compile your applications. You
+    then need to call QString::fromUtf8(), QString::fromLatin1(),
+    or QString::fromLocal8Bit() explicitly if you want to convert the byte
+    array to a QString before doing the comparison.
+*/
+
+/*! \fn bool QByteArray::operator>(const QString &str) const
+
+    Returns \c true if this byte array is lexically greater than the UTF-8
+    encoding of \a str; otherwise returns \c false.
+
+    The comparison is case sensitive.
+
+    You can disable this operator by defining \c
+    QT_NO_CAST_FROM_ASCII when you compile your applications. You
+    then need to call QString::fromUtf8(), QString::fromLatin1(),
+    or QString::fromLocal8Bit() explicitly if you want to convert the byte
+    array to a QString before doing the comparison.
+*/
+
+/*! \fn bool QByteArray::operator<=(const QString &str) const
+
+    Returns \c true if this byte array is lexically less than or equal to the
+    UTF-8 encoding of \a str; otherwise returns \c false.
+
+    The comparison is case sensitive.
+
+    You can disable this operator by defining \c
+    QT_NO_CAST_FROM_ASCII when you compile your applications. You
+    then need to call QString::fromUtf8(), QString::fromLatin1(),
+    or QString::fromLocal8Bit() explicitly if you want to convert the byte
+    array to a QString before doing the comparison.
+*/
+
+/*! \fn bool QByteArray::operator>=(const QString &str) const
+
+    Returns \c true if this byte array is greater than or equal to the UTF-8
+    encoding of \a str; otherwise returns \c false.
+
+    The comparison is case sensitive.
+
+    You can disable this operator by defining \c
+    QT_NO_CAST_FROM_ASCII when you compile your applications. You
+    then need to call QString::fromUtf8(), QString::fromLatin1(),
+    or QString::fromLocal8Bit() explicitly if you want to convert the byte
+    array to a QString before doing the comparison.
+*/
+
 /*! \fn bool operator==(const QByteArray &a1, const QByteArray &a2)
     \relates QByteArray
 
diff --git a/src/corelib/text/qbytearray.h b/src/corelib/text/qbytearray.h
index 68945ec6c4..a625b1846f 100644
--- a/src/corelib/text/qbytearray.h
+++ b/src/corelib/text/qbytearray.h
@@ -308,6 +308,15 @@ public:
 
     Q_REQUIRED_RESULT QByteArray repeated(int times) const;
 
+#if !defined(QT_NO_CAST_FROM_ASCII) && !defined(QT_RESTRICTED_CAST_FROM_ASCII)
+    inline QT_ASCII_CAST_WARN bool operator==(const QString &s2) const;
+    inline QT_ASCII_CAST_WARN bool operator!=(const QString &s2) const;
+    inline QT_ASCII_CAST_WARN bool operator<(const QString &s2) const;
+    inline QT_ASCII_CAST_WARN bool operator>(const QString &s2) const;
+    inline QT_ASCII_CAST_WARN bool operator<=(const QString &s2) const;
+    inline QT_ASCII_CAST_WARN bool operator>=(const QString &s2) const;
+#endif
+
     short toShort(bool *ok = nullptr, int base = 10) const;
     ushort toUShort(bool *ok = nullptr, int base = 10) const;
     int toInt(bool *ok = nullptr, int base = 10) const;
diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index 1e0d7f480a..7f5e460275 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -1259,6 +1259,18 @@ inline QT_ASCII_CAST_WARN bool QString::operator<=(const QByteArray &s) const
 inline QT_ASCII_CAST_WARN bool QString::operator>=(const QByteArray &s) const
 { return QString::compare_helper(constData(), size(), s.constData(), s.size()) >= 0; }
 
+inline bool QByteArray::operator==(const QString &s) const
+{ return QString::compare_helper(s.constData(), s.size(), constData(), qstrnlen(constData(), size())) == 0; }
+inline bool QByteArray::operator!=(const QString &s) const
+{ return QString::compare_helper(s.constData(), s.size(), constData(), qstrnlen(constData(), size())) != 0; }
+inline bool QByteArray::operator<(const QString &s) const
+{ return QString::compare_helper(s.constData(), s.size(), constData(), size()) > 0; }
+inline bool QByteArray::operator>(const QString &s) const
+{ return QString::compare_helper(s.constData(), s.size(), constData(), size()) < 0; }
+inline bool QByteArray::operator<=(const QString &s) const
+{ return QString::compare_helper(s.constData(), s.size(), constData(), size()) >= 0; }
+inline bool QByteArray::operator>=(const QString &s) const
+{ return QString::compare_helper(s.constData(), s.size(), constData(), size()) <= 0; }
 #endif // !defined(QT_NO_CAST_FROM_ASCII) && !defined(QT_RESTRICTED_CAST_FROM_ASCII)
 
 #if !defined(QT_USE_FAST_OPERATOR_PLUS) && !defined(QT_USE_QSTRINGBUILDER)