Doc: use const& in foreach when applicable.

Const reference are slightly faster than doing a copy of the object
on each iteration.

Lead by example by having this pattern right in our documentation

15 files changed, 23 insertions, 23 deletions

diff --git a/doc/src/snippets/code/doc_src_containers.qdoc b/doc/src/snippets/code/doc_src_containers.qdoc
index 5cf2aab..1f86f60 100644
--- a/doc/src/snippets/code/doc_src_containers.qdoc
+++ b/doc/src/snippets/code/doc_src_containers.qdoc
@@ -216,7 +216,7 @@ while (i.hasNext())
 //! [17]
 QLinkedList<QString> list;
 ...
-foreach (QString str, list)
+foreach (const QString &str, list)
     qDebug() << str;
 //! [17]
 
@@ -224,7 +224,7 @@ foreach (QString str, list)
 //! [18]
 QLinkedList<QString> list;
 ...
-foreach (QString str, list) {
+foreach (const QString &str, list) {
     if (str.isEmpty())
         break;
     qDebug() << str;
@@ -235,7 +235,7 @@ foreach (QString str, list) {
 //! [19]
 QMap<QString, int> map;
 ...
-foreach (QString str, map.keys())
+foreach (const QString &str, map.keys())
     qDebug() << str << ":" << map.value(str);
 //! [19]
 
@@ -243,7 +243,7 @@ foreach (QString str, map.keys())
 //! [20]
 QMultiMap<QString, int> map;
 ...
-foreach (QString str, map.uniqueKeys()) {
+foreach (const QString &str, map.uniqueKeys()) {
     foreach (int i, map.values(str))
         qDebug() << str << ":" << i;
 }
diff --git a/doc/src/snippets/code/doc_src_qalgorithms.qdoc b/doc/src/snippets/code/doc_src_qalgorithms.qdoc
index 78634a2..f5a73c6 100644
--- a/doc/src/snippets/code/doc_src_qalgorithms.qdoc
+++ b/doc/src/snippets/code/doc_src_qalgorithms.qdoc
@@ -217,7 +217,7 @@ QStringList list;
 list << "AlPha" << "beTA" << "gamma" << "DELTA";
 
 QMap<QString, QString> map;
-foreach (QString str, list)
+foreach (const QString &str, list)
     map.insert(str.toLower(), str);
 
 list = map.values();
diff --git a/doc/src/snippets/code/doc_src_qset.qdoc b/doc/src/snippets/code/doc_src_qset.qdoc
index ac48edb..c6e1933 100644
--- a/doc/src/snippets/code/doc_src_qset.qdoc
+++ b/doc/src/snippets/code/doc_src_qset.qdoc
@@ -80,7 +80,7 @@ while (i != set.constEnd()) {
 //! [6]
 QSet<QString> set;
 ...
-foreach (QString value, set)
+foreach (const QString &value, set)
     qDebug() << value;
 //! [6]
 
diff --git a/doc/src/snippets/code/doc_src_qt4-tulip.qdoc b/doc/src/snippets/code/doc_src_qt4-tulip.qdoc
index 3d88a0d..f29d3ba 100644
--- a/doc/src/snippets/code/doc_src_qt4-tulip.qdoc
+++ b/doc/src/snippets/code/doc_src_qt4-tulip.qdoc
@@ -47,7 +47,7 @@ foreach (variable, container)
 //! [1]
 QList<QString> list;
 ...
-foreach (QString str, list)
+foreach (const QString &str, list)
     cout << str.ascii() << endl;
 //! [1]
 
diff --git a/doc/src/snippets/code/src_corelib_kernel_qcoreapplication.cpp b/doc/src/snippets/code/src_corelib_kernel_qcoreapplication.cpp
index 2e64505..fb62347 100644
--- a/doc/src/snippets/code/src_corelib_kernel_qcoreapplication.cpp
+++ b/doc/src/snippets/code/src_corelib_kernel_qcoreapplication.cpp
@@ -51,7 +51,7 @@ connect(quitButton, SIGNAL(clicked()), &app, SLOT(quit()));
 
 
 //! [2]
-foreach (QString path, app.libraryPaths())
+foreach (const QString &path, app.libraryPaths())
     do_something(path);
 //! [2]
 
diff --git a/doc/src/snippets/code/src_gui_kernel_qapplication.cpp b/doc/src/snippets/code/src_gui_kernel_qapplication.cpp
index c93a25c..766b249 100644
--- a/doc/src/snippets/code/src_gui_kernel_qapplication.cpp
+++ b/doc/src/snippets/code/src_gui_kernel_qapplication.cpp
@@ -158,13 +158,13 @@ appname -session id
 
 
 //! [10]
-foreach (QString command, mySession.restartCommand())
+foreach (const QString &command, mySession.restartCommand())
     do_something(command);
 //! [10]
 
 
 //! [11]
-foreach (QString command, mySession.discardCommand())
+foreach (const QString &command, mySession.discardCommand())
     do_something(command);
 //! [11]
 
diff --git a/doc/src/snippets/code/src_network_kernel_qhostinfo.cpp b/doc/src/snippets/code/src_network_kernel_qhostinfo.cpp
index 3871289..99deb20 100644
--- a/doc/src/snippets/code/src_network_kernel_qhostinfo.cpp
+++ b/doc/src/snippets/code/src_network_kernel_qhostinfo.cpp
@@ -68,7 +68,7 @@ void MyWidget::lookedUp(const QHostInfo &host)
         return;
     }
 
-    foreach (QHostAddress address, host.addresses())
+    foreach (const QHostAddress &address, host.addresses())
         qDebug() << "Found address:" << address.toString();
 }
 //! [3]
diff --git a/doc/src/snippets/code/src_network_ssl_qsslcertificate.cpp b/doc/src/snippets/code/src_network_ssl_qsslcertificate.cpp
index 5c9421f..937dbb9 100644
--- a/doc/src/snippets/code/src_network_ssl_qsslcertificate.cpp
+++ b/doc/src/snippets/code/src_network_ssl_qsslcertificate.cpp
@@ -39,7 +39,7 @@
 ****************************************************************************/
 
 //! [0]
-foreach (QSslCertificate cert, QSslCertificate::fromPath("C:/ssl/certificate.*.pem", QSsl::Pem,
+foreach (const QSslCertificate &cert, QSslCertificate::fromPath("C:/ssl/certificate.*.pem", QSsl::Pem,
                                                          QRegExp::Wildcard)) {
     qDebug() << cert.issuerInfo(QSslCertificate::Organization);
 }
diff --git a/doc/src/snippets/droparea.cpp b/doc/src/snippets/droparea.cpp
index bbcf82d..bb49dd7 100644
--- a/doc/src/snippets/droparea.cpp
+++ b/doc/src/snippets/droparea.cpp
@@ -130,7 +130,7 @@ QPixmap DropArea::extractPixmap(const QByteArray &data, const QString &format)
     QList<QByteArray> imageFormats = QImageReader::supportedImageFormats();
     QPixmap pixmap;
 
-    foreach (QByteArray imageFormat, imageFormats) {
+    foreach (const QByteArray &imageFormat, imageFormats) {
         if (format.mid(6) == QString(imageFormat)) {
             pixmap.loadFromData(data, imageFormat);
             break;
diff --git a/doc/src/snippets/picture/picture.cpp b/doc/src/snippets/picture/picture.cpp
index 0c5712a..5283978 100644
--- a/doc/src/snippets/picture/picture.cpp
+++ b/doc/src/snippets/picture/picture.cpp
@@ -76,7 +76,7 @@ int main()
         // FORMATS
 //! [2]
         QStringList list = QPicture::inputFormatList();
-        foreach (QString string, list)
+        foreach (const QString &string, list)
             myProcessing(string);
 //! [2]
     }
@@ -85,7 +85,7 @@ int main()
         // OUTPUT
 //! [3]
         QStringList list = QPicture::outputFormatList();
-        foreach (QString string, list)
+        foreach (const QString &string, list)
             myProcessing(string);
 //! [3]
     }
diff --git a/doc/src/snippets/qfontdatabase/main.cpp b/doc/src/snippets/qfontdatabase/main.cpp
index 7f939de..1b8ff42 100644
--- a/doc/src/snippets/qfontdatabase/main.cpp
+++ b/doc/src/snippets/qfontdatabase/main.cpp
@@ -50,11 +50,11 @@ int main(int argc, char **argv)
     fontTree.setColumnCount(2);
     fontTree.setHeaderLabels(QStringList() << "Font" << "Smooth Sizes");
 
-    foreach (QString family, database.families()) {
+    foreach (const QString &family, database.families()) {
         QTreeWidgetItem *familyItem = new QTreeWidgetItem(&fontTree);
         familyItem->setText(0, family);
 
-        foreach (QString style, database.styles(family)) {
+        foreach (const QString &style, database.styles(family)) {
             QTreeWidgetItem *styleItem = new QTreeWidgetItem(familyItem);
             styleItem->setText(0, style);
 
diff --git a/doc/src/snippets/qlistview-dnd/model.cpp b/doc/src/snippets/qlistview-dnd/model.cpp
index d310c03..bca71ee 100644
--- a/doc/src/snippets/qlistview-dnd/model.cpp
+++ b/doc/src/snippets/qlistview-dnd/model.cpp
@@ -109,7 +109,7 @@ bool DragDropListModel::dropMimeData(const QMimeData *data,
 
 //! [6]
     insertRows(beginRow, rows, QModelIndex());
-    foreach (QString text, newItems) {
+    foreach (const QString &text, newItems) {
         QModelIndex idx = index(beginRow, 0, QModelIndex());
         setData(idx, text);
         beginRow++;
@@ -139,7 +139,7 @@ QMimeData *DragDropListModel::mimeData(const QModelIndexList &indexes) const
 
     QDataStream stream(&encodedData, QIODevice::WriteOnly);
 
-    foreach (QModelIndex index, indexes) {
+    foreach (const QModelIndex &index, indexes) {
         if (index.isValid()) {
             QString text = data(index, Qt::DisplayRole).toString();
             stream << text;
diff --git a/doc/src/snippets/qstringlist/main.cpp b/doc/src/snippets/qstringlist/main.cpp
index 76785f1..9ada319 100644
--- a/doc/src/snippets/qstringlist/main.cpp
+++ b/doc/src/snippets/qstringlist/main.cpp
@@ -118,7 +118,7 @@ Widget::Widget(QWidget *parent)
 
     result.clear();
 //! [12]
-    foreach (QString str, list) {
+    foreach (const QString &str, list) {
         if (str.contains("Bill"))
             result += str;
     }
diff --git a/doc/src/snippets/qtreeview-dnd/dragdropmodel.cpp b/doc/src/snippets/qtreeview-dnd/dragdropmodel.cpp
index 2d01240..620a716 100644
--- a/doc/src/snippets/qtreeview-dnd/dragdropmodel.cpp
+++ b/doc/src/snippets/qtreeview-dnd/dragdropmodel.cpp
@@ -123,7 +123,7 @@ QMimeData *DragDropModel::mimeData(const QModelIndexList &indexes) const
 
     QDataStream stream(&encodedData, QIODevice::WriteOnly);
 
-    foreach (QModelIndex index, indexes) {
+    foreach (const QModelIndex &index, indexes) {
         if (index.isValid()) {
             QString text = data(index, Qt::DisplayRole).toString();
             stream << index.internalId() << index.row() << index.column() << text;
diff --git a/doc/src/snippets/widgets-tutorial/nestedlayouts/main.cpp b/doc/src/snippets/widgets-tutorial/nestedlayouts/main.cpp
index 6a49be8..35d2fa7 100644
--- a/doc/src/snippets/widgets-tutorial/nestedlayouts/main.cpp
+++ b/doc/src/snippets/widgets-tutorial/nestedlayouts/main.cpp
@@ -72,9 +72,9 @@ int main(int argc, char *argv[])
         << (QStringList() << "David Bradley" << "42")
         << (QStringList() << "Knut Walters" << "25")
         << (QStringList() << "Andrea Jones" << "34");
-    foreach (QStringList row, rows) {
+    foreach (const QStringList &row, rows) {
         QList<QStandardItem *> items;
-        foreach (QString text, row)
+        foreach (const QString &text, row)
             items.append(new QStandardItem(text));
         model.appendRow(items);
     }