Fix QFileSystemModel to not install useless watchers on the filesystem

When someone call setRootPath we need to remove the previous watcher.
This save memory and also it avoids Qt Creator to run out of filesystem
watcher which then leads to a crash. If you call setRootPath on the
previous path all changes that might happen in between will be propagated
in the model.

Task-number:QTBUG-8632
Reviewed-by:Friedemann Kleint

1 files changed, 10 insertions, 0 deletions

diff --git a/src/gui/dialogs/qfilesystemmodel.cpp b/src/gui/dialogs/qfilesystemmodel.cpp
index 6fd947ce3b..3757ad7295 100644
--- a/src/gui/dialogs/qfilesystemmodel.cpp
+++ b/src/gui/dialogs/qfilesystemmodel.cpp
@@ -1361,6 +1361,16 @@ QModelIndex QFileSystemModel::setRootPath(const QString &newPath)
     if (!showDrives && !newPathDir.exists())
         return d->index(rootPath());
 
+    //We remove the watcher on the previous path
+    if (!rootPath().isEmpty()) {
+        //This remove the watcher for the old rootPath
+        d->fileInfoGatherer.removePath(rootPath());
+        //This line "marks" the node as dirty, so the next fetchMore
+        //call on the path will ask the gatherer to install a watcher again
+        //But it doesn't re-fetch everything
+        d->node(rootPath())->populatedChildren = false;
+    }
+
     // We have a new valid root path
     d->rootDir = newPathDir;
     QModelIndex newRootIndex;