QVector - add remove functions

This patch adds the functions removeFirst() and removeLast().
Functions that QList has.

Beside making these functions, pop_back and pop_front are
redirected to these rather than calling erase.

Change-Id: Ifc5f8a78e33f436f06f21095a920ec5d4311fd6f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qvector.cpp

@@ -544,6 +544,26 @@
     \sa insert(), replace(), fill()
 */
 
+/*! \fn void QVector::removeFirst()
+    \since 5.1
+    Removes the first item in the vector. Calling this function is
+    equivalent to calling remove(0). The vector must not be empty. If
+    the vector can be empty, call isEmpty() before calling this
+    function.
+
+    \sa remove(), isEmpty()
+*/
+
+/*! \fn void QVector::removeLast()
+    \since 5.1
+    Removes the last item in the vector. Calling this function is
+    equivalent to calling remove(size() - 1). The vector must not be
+    empty. If the vector can be empty, call isEmpty() before calling
+    this function.
+
+    \sa remove(), removeFirst(), isEmpty()
+*/
+
 /*! \fn QVector &QVector::fill(const T &value, int size = -1)
 
     Assigns \a value to all items in the vector. If \a size is
@@ -773,13 +793,13 @@
 /*! \fn void QVector::pop_front()
 
     This function is provided for STL compatibility. It is equivalent
-    to erase(begin()).
+    to removeFirst().
 */
 
 /*! \fn void QVector::pop_back()
 
     This function is provided for STL compatibility. It is equivalent
-    to erase(end() - 1).
+    to removeLast().
 */
 
 /*! \fn T& QVector::front()

src/corelib/tools/qvector.h

@@ -138,6 +138,8 @@ public:
     void replace(int i, const T &t);
     void remove(int i);
     void remove(int i, int n);
+    inline void removeFirst() { Q_ASSERT(!isEmpty()); erase(d->begin()); }
+    inline void removeLast()  { Q_ASSERT(!isEmpty()); erase(d->end() - 1); }
 
     QVector<T> &fill(const T &t, int size = -1);
 
@@ -198,8 +200,8 @@ public:
     typedef int size_type;
     inline void push_back(const T &t) { append(t); }
     inline void push_front(const T &t) { prepend(t); }
-    void pop_back() { Q_ASSERT(!isEmpty()); erase(d->end() - 1); }
-    void pop_front() { Q_ASSERT(!isEmpty()); erase(d->begin()); }
+    void pop_back() { removeLast(); }
+    void pop_front() { removeFirst(); }
     inline bool empty() const
     { return d->size == 0; }
     inline T& front() { return first(); }

tests/auto/corelib/tools/qvector/tst_qvector.cpp

@@ -236,6 +236,7 @@ private slots:
     void removeInt() const;
     void removeMovable() const;
     void removeCustom() const;
+    void removeFirstLast() const;
     void resizePOD_data() const;
     void resizePOD() const;
     void resizeComplexMovable_data() const;
@@ -1393,6 +1394,81 @@ void tst_QVector::removeCustom() const
     QCOMPARE(instancesCount, Custom::counter.loadAcquire());
 }
 
+struct RemoveLastTestClass
+{
+    RemoveLastTestClass() { other = 0; deleted = false; }
+    RemoveLastTestClass *other;
+    bool deleted;
+    ~RemoveLastTestClass()
+    {
+        deleted = true;
+        if (other)
+            other->other = 0;
+    }
+};
+
+void tst_QVector::removeFirstLast() const
+{
+    // pop_pack - pop_front
+    QVector<int> t;
+    t.append(1);
+    t.append(2);
+    t.append(3);
+    t.append(4);
+    t.pop_front();
+    QCOMPARE(t.size(), 3);
+    QCOMPARE(t.at(0), 2);
+    t.pop_back();
+    QCOMPARE(t.size(), 2);
+    QCOMPARE(t.at(0), 2);
+    QCOMPARE(t.at(1), 3);
+
+    // remove first
+    QVector<int> x, y;
+    x.append(1);
+    x.append(2);
+    y = x;
+    x.removeFirst();
+    QCOMPARE(x.size(), 1);
+    QCOMPARE(y.size(), 2);
+    QCOMPARE(x.at(0), 2);
+
+    // remove Last
+    QVector<RemoveLastTestClass> v;
+    v.resize(2);
+    v[0].other = &(v[1]);
+    v[1].other = &(v[0]);
+    // Check dtor - complex type
+    QVERIFY(v.at(0).other != 0);
+    v.removeLast();
+    QVERIFY(v.at(0).other == 0);
+    QCOMPARE(v.at(0).deleted, false);
+    // check iterator
+    int count = 0;
+    for (QVector<RemoveLastTestClass>::const_iterator i = v.constBegin(); i != v.constEnd(); ++i) {
+        ++count;
+        QVERIFY(i->other == 0);
+        QCOMPARE(i->deleted, false);
+    }
+    // Check size
+    QCOMPARE(count, 1);
+    QCOMPARE(v.size(), 1);
+    v.removeLast();
+    QCOMPARE(v.size(), 0);
+    // Check if we do correct realloc
+    QVector<int> v2, v3;
+    v2.append(1);
+    v2.append(2);
+    v3 = v2; // shared
+    v2.removeLast();
+    QCOMPARE(v2.size(), 1);
+    QCOMPARE(v3.size(), 2);
+    QCOMPARE(v2.at(0), 1);
+    QCOMPARE(v3.at(0), 1);
+    QCOMPARE(v3.at(1), 2);
+}
+
+
 void tst_QVector::resizePOD_data() const
 {
     QTest::addColumn<QVector<int> >("vector");