Testlib: Replace linked lists in QTestTablePrivate by std::vector.

This speeds up tests/auto/corelib/tools/qchar which spends a lot
of time in QTestTablePrivate::elementAt(), QTestTablePrivate::dataAt()
from 6s to 500ms on an average Linux machine.

Task-number: QTBUG-38890
Change-Id: I16b75819f88ca7974a581affd8409f7b4038a712
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>

src/testlib/qtesttable.cpp

@@ -38,37 +38,30 @@
 #include <QtCore/qmetaobject.h>
 
 #include <string.h>
+#include <vector>
+#include <algorithm>
 
 QT_BEGIN_NAMESPACE
 
 class QTestTablePrivate
 {
 public:
-    struct ElementList
-    {
-        ElementList(): elementName(0), elementType(0), next(0) {}
-        const char *elementName;
-        int elementType;
-        ElementList *next;
+    struct Element {
+        Element() : name(Q_NULLPTR), type(0) {}
+        Element(const char *n, int t) : name(n), type(t) {}
+
+        const char *name;
+        int type;
     };
 
-    struct DataList
-    {
-        DataList(): data(0), next(0) {}
-        QTestData *data;
-        DataList *next;
-    };
+    typedef std::vector<Element> ElementList;
+    ElementList elementList;
 
-    QTestTablePrivate(): list(0), dataList(0) {}
-    ~QTestTablePrivate();
+    typedef std::vector<QTestData *> DataList;
+    DataList dataList;
 
-    ElementList *list;
-    DataList *dataList;
-
-    void addColumn(int elemType, const char *elemName);
-    void addRow(QTestData *data);
-    ElementList *elementAt(int index);
-    QTestData *dataAt(int index);
+    void addColumn(int elemType, const char *elemName) { elementList.push_back(Element(elemName, elemType)); }
+    void addRow(QTestData *data) { dataList.push_back(data); }
 
     static QTestTable *currentTestTable;
     static QTestTable *gTable;
@@ -77,74 +70,6 @@ public:
 QTestTable *QTestTablePrivate::currentTestTable = 0;
 QTestTable *QTestTablePrivate::gTable = 0;
 
-QTestTablePrivate::ElementList *QTestTablePrivate::elementAt(int index)
-{
-    ElementList *iter = list;
-    for (int i = 0; i < index; ++i) {
-        if (!iter)
-            return 0;
-        iter = iter->next;
-    }
-    return iter;
-}
-
-QTestData *QTestTablePrivate::dataAt(int index)
-{
-    DataList *iter = dataList;
-    for (int i = 0; i < index; ++i) {
-        if (!iter)
-            return 0;
-        iter = iter->next;
-    }
-    return iter ? iter->data : 0;
-}
-
-QTestTablePrivate::~QTestTablePrivate()
-{
-    DataList *dit = dataList;
-    while (dit) {
-        DataList *next = dit->next;
-        delete dit->data;
-        delete dit;
-        dit = next;
-    }
-    ElementList *iter = list;
-    while (iter) {
-        ElementList *next = iter->next;
-        delete iter;
-        iter = next;
-    }
-}
-
-void QTestTablePrivate::addColumn(int elemType, const char *elemName)
-{
-    ElementList *item = new ElementList;
-    item->elementName = elemName;
-    item->elementType = elemType;
-    if (!list) {
-        list = item;
-        return;
-    }
-    ElementList *last = list;
-    while (last->next != 0)
-        last = last->next;
-    last->next = item;
-}
-
-void QTestTablePrivate::addRow(QTestData *data)
-{
-    DataList *item = new DataList;
-    item->data = data;
-    if (!dataList) {
-        dataList = item;
-        return;
-    }
-    DataList *last = dataList;
-    while (last->next != 0)
-        last = last->next;
-    last->next = item;
-}
-
 void QTestTable::addColumn(int type, const char *name)
 {
     QTEST_ASSERT(type);
@@ -155,30 +80,17 @@ void QTestTable::addColumn(int type, const char *name)
 
 int QTestTable::elementCount() const
 {
-    QTestTablePrivate::ElementList *item = d->list;
-    int count = 0;
-    while (item) {
-        ++count;
-        item = item->next;
-    }
-    return count;
+    return int(d->elementList.size());
 }
 
-
 int QTestTable::dataCount() const
 {
-    QTestTablePrivate::DataList *item = d->dataList;
-    int count = 0;
-    while (item) {
-        ++count;
-        item = item->next;
-    }
-    return count;
+    return int(d->dataList.size());
 }
 
 bool QTestTable::isEmpty() const
 {
-    return !d->list;
+    return d->elementList.empty();
 }
 
 QTestData *QTestTable::newData(const char *tag)
@@ -202,38 +114,43 @@ QTestTable::~QTestTable()
 
 int QTestTable::elementTypeId(int index) const
 {
-    QTestTablePrivate::ElementList *item = d->elementAt(index);
-    if (!item)
-        return -1;
-    return item->elementType;
+    return size_t(index) < d->elementList.size() ? d->elementList[index].type : -1;
 }
 
 const char *QTestTable::dataTag(int index) const
 {
-    QTestTablePrivate::ElementList *item = d->elementAt(index);
-    if (!item)
-        return 0;
-    return item->elementName;
+    return size_t(index) < d->elementList.size() ? d->elementList[index].name : Q_NULLPTR;
 }
 
 QTestData *QTestTable::testData(int index) const
 {
-    return d->dataAt(index);
+    return size_t(index) < d->dataList.size() ? d->dataList[index] : Q_NULLPTR;
 }
 
+class NamePredicate : public std::unary_function<QTestTablePrivate::Element, bool>
+{
+public:
+    explicit NamePredicate(const char *needle) : m_needle(needle) {}
+
+    bool operator()(const QTestTablePrivate::Element &e) const
+        { return !strcmp(e.name, m_needle); }
+
+private:
+    const char *m_needle;
+};
+
 int QTestTable::indexOf(const char *elementName) const
 {
+    typedef QTestTablePrivate::ElementList::const_iterator It;
+
     QTEST_ASSERT(elementName);
 
-    QTestTablePrivate::ElementList *item = d->list;
-    int i = 0;
-    while (item) {
-        if (strcmp(elementName, item->elementName) == 0)
-            return i;
-        item = item->next;
-        ++i;
-    }
-    return -1;
+    const QTestTablePrivate::ElementList &elementList = d->elementList;
+
+    const It it = std::find_if(elementList.begin(), elementList.end(),
+                               NamePredicate(elementName));
+    return it != elementList.end() ?
+        int(it - elementList.begin()) : -1;
 }
 
 QTestTable *QTestTable::globalTestTable()