QString, QByteArray: add removeAt/First/Last() convenience methods

Requested in codereview.qt-project.org/c/qt/qtbase/+/441770

[ChangeLog][QtCore][Text] Add removeAt/First/Last() convenience methods to
QString and QByteArray

Change-Id: I48a803e456e70cc51d51726a5e3aa7c125aedb1c
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/text/qbytearray.cpp

@@ -2270,6 +2270,38 @@ QByteArray &QByteArray::remove(qsizetype pos, qsizetype len)
     return *this;
 }
 
+/*!
+  \fn QByteArray &QByteArray::removeAt(qsizetype pos)
+
+  \since 6.5
+
+  Removes the character at index \a pos. If \a pos is out of bounds
+  (i.e. \a pos >= size()) this function does nothing.
+
+  \sa remove()
+*/
+
+/*!
+  \fn QByteArray &QByteArray::removeFirst()
+
+  \since 6.5
+
+  Removes the first character in this byte array. If the byte array is empty,
+  this function does nothing.
+
+  \sa remove()
+*/
+/*!
+  \fn QByteArray &QByteArray::removeLast()
+
+  \since 6.5
+
+  Removes the last character in this byte array. If the byte array is empty,
+  this function does nothing.
+
+  \sa remove()
+*/
+
 /*!
     \fn template <typename Predicate> QByteArray &QByteArray::removeIf(Predicate pred)
     \since 6.1

src/corelib/text/qbytearray.h

@@ -233,6 +233,11 @@ public:
     { return insert(i, QByteArrayView(s, len)); }
 
     QByteArray &remove(qsizetype index, qsizetype len);
+    QByteArray &removeAt(qsizetype pos)
+    { return size_t(pos) < size_t(size()) ? remove(pos, 1) : *this; }
+    QByteArray &removeFirst() { return !isEmpty() ? remove(0, 1) : *this; }
+    QByteArray &removeLast() { return !isEmpty() ? remove(size() - 1, 1) : *this; }
+
     template <typename Predicate>
     QByteArray &removeIf(Predicate pred)
     {

src/corelib/text/qstring.cpp

@@ -3385,6 +3385,39 @@ QString &QString::remove(QLatin1StringView str, Qt::CaseSensitivity cs)
     return *this;
 }
 
+/*!
+  \fn QString &QString::removeAt(qsizetype pos)
+
+  \since 6.5
+
+  Removes the character at index \a pos. If \a pos is out of bounds
+  (i.e. \a pos >= size()), this function does nothing.
+
+  \sa remove()
+*/
+
+/*!
+  \fn QString &QString::removeFirst()
+
+  \since 6.5
+
+  Removes the first character in this string. If the string is empty,
+  this function does nothing.
+
+  \sa remove()
+*/
+
+/*!
+  \fn QString &QString::removeLast()
+
+  \since 6.5
+
+  Removes the last character in this string. If the string is empty,
+  this function does nothing.
+
+  \sa remove()
+*/
+
 /*!
   Removes every occurrence of the character \a ch in this string, and
   returns a reference to this string.

src/corelib/text/qstring.h

@@ -704,6 +704,12 @@ public:
     QString &remove(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive);
     QString &remove(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive);
     QString &remove(const QString &s, Qt::CaseSensitivity cs = Qt::CaseSensitive);
+
+    QString &removeAt(qsizetype pos)
+    { return size_t(pos) < size_t(size()) ? remove(pos, 1) : *this; }
+    QString &removeFirst() { return !isEmpty() ? remove(0, 1) : *this; }
+    QString &removeLast() { return !isEmpty() ? remove(size() - 1, 1) : *this; }
+
     template <typename Predicate>
     QString &removeIf(Predicate pred)
     {

tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp

@@ -53,6 +53,7 @@ private slots:
     void insertExtended();
     void remove_data();
     void remove();
+    void remove_extra();
     void removeIf();
     void erase();
     void erase_single_arg();
@@ -1070,6 +1071,22 @@ void tst_QByteArray::remove()
     QCOMPARE(ba2.remove(position, length), expected);
 }
 
+void tst_QByteArray::remove_extra()
+{
+    QByteArray ba = "Clock";
+    ba.removeFirst();
+    QCOMPARE(ba, "lock");
+    ba.removeLast();
+    QCOMPARE(ba, "loc");
+    ba.removeAt(ba.indexOf('o'));
+    QCOMPARE(ba, "lc");
+    ba.clear();
+    // No crash on empty byte arrays
+    ba.removeFirst();
+    ba.removeLast();
+    ba.removeAt(2);
+}
+
 void tst_QByteArray::removeIf()
 {
     auto removeA = [](const char c) { return c == 'a' || c == 'A'; };

tests/auto/corelib/text/qstring/tst_qstring.cpp

@@ -3452,6 +3452,21 @@ void tst_QString::remove_extra()
         s1.remove(0, 1);
         QCOMPARE(s1, s);
     }
+
+    {
+        QString s = "Clock";
+        s.removeFirst();
+        QCOMPARE(s, "lock");
+        s.removeLast();
+        QCOMPARE(s, "loc");
+        s.removeAt(s.indexOf('o'));
+        QCOMPARE(s, "lc");
+        s.clear();
+        // No crash on empty strings
+        s.removeFirst();
+        s.removeLast();
+        s.removeAt(2);
+    }
 }
 
 void tst_QString::erase_single_arg()