Extract method `bool QDomNodeListPrivate::maybeCreateList()`

Extract duplicated logic to own method, and call where previously used.
Also, make `QDomNodeListPrivate::[list|timestamp]` mutable, to allow
`maybeCreateList()` and `createList()` to be `const` methods, and avoid
`const_cast` in `QDomNodeListPrivate::length()`.

Task-number: QTBUG-115076
Change-Id: I4f3a27315da28082a12cc4f5653567039b4cb376
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

2 files changed, 14 insertions, 14 deletions

diff --git a/src/xml/dom/qdom.cpp b/src/xml/dom/qdom.cpp
index 2ac044004e..b25cdf487f 100644
--- a/src/xml/dom/qdom.cpp
+++ b/src/xml/dom/qdom.cpp
@@ -649,7 +649,7 @@ bool QDomNodeListPrivate::operator!=(const QDomNodeListPrivate &other) const
     return !operator==(other);
 }
 
-void QDomNodeListPrivate::createList()
+void QDomNodeListPrivate::createList() const
 {
     if (!node_impl)
         return;
@@ -703,16 +703,21 @@ void QDomNodeListPrivate::createList()
     }
 }
 
-QDomNodePrivate* QDomNodeListPrivate::item(int index)
+bool QDomNodeListPrivate::maybeCreateList() const
 {
     if (!node_impl)
-        return nullptr;
+        return false;
 
     const QDomDocumentPrivate *const doc = node_impl->ownerDocument();
     if (!doc || timestamp != doc->nodeListTime)
         createList();
 
-    if (index >= list.size())
+    return true;
+}
+
+QDomNodePrivate *QDomNodeListPrivate::item(int index)
+{
+    if (!maybeCreateList() || index >= list.size() || index < 0)
         return nullptr;
 
     return list.at(index);
@@ -720,15 +725,9 @@ QDomNodePrivate* QDomNodeListPrivate::item(int index)
 
 int QDomNodeListPrivate::length() const
 {
-    if (!node_impl)
+    if (!maybeCreateList())
         return 0;
 
-    const QDomDocumentPrivate *const doc = node_impl->ownerDocument();
-    if (!doc || timestamp != doc->nodeListTime) {
-        QDomNodeListPrivate *that = const_cast<QDomNodeListPrivate *>(this);
-        that->createList();
-    }
-
     return list.size();
 }
 
diff --git a/src/xml/dom/qdom_p.h b/src/xml/dom/qdom_p.h
index fb71f8ce23..b2ecd534c8 100644
--- a/src/xml/dom/qdom_p.h
+++ b/src/xml/dom/qdom_p.h
@@ -142,7 +142,8 @@ public:
     bool operator==(const QDomNodeListPrivate &) const;
     bool operator!=(const QDomNodeListPrivate &) const;
 
-    void createList();
+    void createList() const;
+    bool maybeCreateList() const;
     QDomNodePrivate *item(int index);
     int length() const;
 
@@ -153,8 +154,8 @@ public:
     QDomNodePrivate *node_impl;
     QString tagname;
     QString nsURI;
-    QList<QDomNodePrivate *> list;
-    long timestamp;
+    mutable QList<QDomNodePrivate *> list;
+    mutable long timestamp;
 };
 
 class QDomNamedNodeMapPrivate