Added two convenience functions to QXmlStreamReader

QXmlStreamReader::readNextStartElement reads until the next start
element within the current element, or returns false when no such
element is encountered before the end element is reached. It simplifies
the common case of iterating over the elements in an XML document.

QXmlStreamReader::skipCurrentElement reads until the end element of the
current element, skipping any child elements. This functionality was
requested in two tasks, and a similar function 'readUnknownElement' was
present in Qt's stream reader example.

Autotest is included, example and documentation have been updated.

Task-number: 238793
Reviewed-by: mae

2 files changed, 34 insertions, 74 deletions

diff --git a/examples/xml/streambookmarks/xbelreader.cpp b/examples/xml/streambookmarks/xbelreader.cpp
index 47c8c3d269..729fcf8f23 100644
--- a/examples/xml/streambookmarks/xbelreader.cpp
+++ b/examples/xml/streambookmarks/xbelreader.cpp
@@ -62,59 +62,31 @@ bool XbelReader::read(QIODevice *device)
 {
     setDevice(device);
 
-    while (!atEnd()) {
-        readNext();
-
-        if (isStartElement()) {
-            if (name() == "xbel" && attributes().value("version") == "1.0")
-                readXBEL();
-            else
-                raiseError(QObject::tr("The file is not an XBEL version 1.0 file."));
-        }
+    if (readNextStartElement()) {
+        if (name() == "xbel" && attributes().value("version") == "1.0")
+            readXBEL();
+        else
+            raiseError(QObject::tr("The file is not an XBEL version 1.0 file."));
     }
 
     return !error();
 }
 //! [1]
 
-//! [2]
-void XbelReader::readUnknownElement()
-{
-    Q_ASSERT(isStartElement());
-
-    while (!atEnd()) {
-        readNext();
-
-        if (isEndElement())
-            break;
-
-        if (isStartElement())
-            readUnknownElement();
-    }
-}
-//! [2]
-
 //! [3]
 void XbelReader::readXBEL()
 {
     Q_ASSERT(isStartElement() && name() == "xbel");
 
-    while (!atEnd()) {
-        readNext();
-
-        if (isEndElement())
-            break;
-
-        if (isStartElement()) {
-            if (name() == "folder")
-                readFolder(0);
-            else if (name() == "bookmark")
-                readBookmark(0);
-            else if (name() == "separator")
-                readSeparator(0);
-            else
-                readUnknownElement();
-        }
+    while (readNextStartElement()) {
+        if (name() == "folder")
+            readFolder(0);
+        else if (name() == "bookmark")
+            readBookmark(0);
+        else if (name() == "separator")
+            readSeparator(0);
+        else
+            readUnknownElement();
     }
 }
 //! [3]
@@ -132,10 +104,12 @@ void XbelReader::readTitle(QTreeWidgetItem *item)
 //! [5]
 void XbelReader::readSeparator(QTreeWidgetItem *item)
 {
+    Q_ASSERT(isStartElement() && name() == "separator");
+
     QTreeWidgetItem *separator = createChildItem(item);
     separator->setFlags(item->flags() & ~Qt::ItemIsSelectable);
     separator->setText(0, QString(30, 0xB7));
-    readElementText();
+    skipCurrentElement();
 }
 //! [5]
 
@@ -147,24 +121,17 @@ void XbelReader::readFolder(QTreeWidgetItem *item)
     bool folded = (attributes().value("folded") != "no");
     treeWidget->setItemExpanded(folder, !folded);
 
-    while (!atEnd()) {
-        readNext();
-
-        if (isEndElement())
-            break;
-
-        if (isStartElement()) {
-            if (name() == "title")
-                readTitle(folder);
-            else if (name() == "folder")
-                readFolder(folder);
-            else if (name() == "bookmark")
-                readBookmark(folder);
-            else if (name() == "separator")
-                readSeparator(folder);
-            else
-                readUnknownElement();
-        }
+    while (readNextStartElement()) {
+        if (name() == "title")
+            readTitle(folder);
+        else if (name() == "folder")
+            readFolder(folder);
+        else if (name() == "bookmark")
+            readBookmark(folder);
+        else if (name() == "separator")
+            readSeparator(folder);
+        else
+            skipCurrentElement();
     }
 }
 
@@ -177,18 +144,12 @@ void XbelReader::readBookmark(QTreeWidgetItem *item)
     bookmark->setIcon(0, bookmarkIcon);
     bookmark->setText(0, QObject::tr("Unknown title"));
     bookmark->setText(1, attributes().value("href").toString());
-    while (!atEnd()) {
-        readNext();
-
-        if (isEndElement())
-            break;
-
-        if (isStartElement()) {
-            if (name() == "title")
-                readTitle(bookmark);
-            else
-                readUnknownElement();
-        }
+
+    while (readNextStartElement()) {
+        if (name() == "title")
+            readTitle(bookmark);
+        else
+            skipCurrentElement();
     }
 }
 
diff --git a/examples/xml/streambookmarks/xbelreader.h b/examples/xml/streambookmarks/xbelreader.h
index 80f0a28650..2debadce3d 100644
--- a/examples/xml/streambookmarks/xbelreader.h
+++ b/examples/xml/streambookmarks/xbelreader.h
@@ -62,7 +62,6 @@ public:
 
 private:
 //! [2]
-    void readUnknownElement();
     void readXBEL();
     void readTitle(QTreeWidgetItem *item);
     void readSeparator(QTreeWidgetItem *item);