De-inline QFileSystemModel::fileInfo() and implement it efficiently

De-inline the method, and return the file info that's already being
cached by the model.

This is ok to do in a minor release, as apps compiled against an older
version of Qt will simply continue to use the less efficient
implementation.

Change-Id: I164c7961a8cf97447638af316512326442767dd8
Task-number: QTBUG-30902
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>

src/widgets/dialogs/qfilesystemmodel.cpp

@@ -154,6 +154,11 @@ QT_BEGIN_NAMESPACE
     Returns the QFileInfo for the item stored in the model under the given
     \a index.
 */
+QFileInfo QFileSystemModel::fileInfo(const QModelIndex &index) const
+{
+    Q_D(const QFileSystemModel);
+    return d->node(index)->fileInfo();
+}
 
 /*!
     \fn void QFileSystemModel::rootPathChanged(const QString &newPath);

src/widgets/dialogs/qfilesystemmodel.h

@@ -132,7 +132,7 @@ public:
     inline QString fileName(const QModelIndex &index) const;
     inline QIcon fileIcon(const QModelIndex &index) const;
     QFile::Permissions permissions(const QModelIndex &index) const;
-    inline QFileInfo fileInfo(const QModelIndex &index) const;
+    QFileInfo fileInfo(const QModelIndex &index) const;
     bool remove(const QModelIndex &index);
 
 protected:
@@ -156,8 +156,6 @@ inline QString QFileSystemModel::fileName(const QModelIndex &aindex) const
 { return aindex.data(Qt::DisplayRole).toString(); }
 inline QIcon QFileSystemModel::fileIcon(const QModelIndex &aindex) const
 { return qvariant_cast<QIcon>(aindex.data(Qt::DecorationRole)); }
-inline QFileInfo QFileSystemModel::fileInfo(const QModelIndex &aindex) const
-{ return QFileInfo(filePath(aindex)); }
 
 #endif // QT_NO_FILESYSTEMMODEL
 

src/widgets/dialogs/qfilesystemmodel_p.h

@@ -107,6 +107,7 @@ public:
                 return true;
             return false;
         }
+        inline QFileInfo fileInfo() const { if (info) return info->fileInfo(); return QFileInfo(); }
         inline bool isFile() const { if (info) return info->isFile(); return true; }
         inline bool isSystem() const { if (info) return info->isSystem(); return true; }
         inline bool isHidden() const { if (info) return info->isHidden(); return false; }