FileManager: Graceful handling of access errors

A neat error message is displayed when failing to open a directory!

Applications/FileManager/DirectoryView.cpp

@@ -91,9 +91,23 @@ DirectoryView::DirectoryView()
     m_item_view->set_model_column(GUI::FileSystemModel::Column::Name);
     m_columns_view->set_model_column(GUI::FileSystemModel::Column::Name);
 
-    m_model->on_root_path_change = [this] {
+    m_model->on_error = [this](int error, const char* error_string) {
+        bool quit = false;
+        if (m_path_history.size())
+            open(m_path_history.at(m_path_history_position));
+        else
+            quit = true;
+        
+        if (on_error)
+            on_error(error, error_string, quit);        
+    };
+
+    m_model->on_complete = [this] {
         m_table_view->selection().clear();
         m_item_view->selection().clear();
+
+        add_path_to_history(model().root_path());
+
         if (on_path_change)
             on_path_change(model().root_path());
     };
@@ -197,6 +211,9 @@ void DirectoryView::set_view_mode(ViewMode mode)
 
 void DirectoryView::add_path_to_history(const StringView& path)
 {
+    if (m_path_history.size() && m_path_history.at(m_path_history_position) == path)
+        return;
+
     if (m_path_history_position < m_path_history.size())
         m_path_history.resize(m_path_history_position + 1);
 
@@ -210,7 +227,6 @@ void DirectoryView::open(const StringView& path)
         model().update();
         return;
     }
-    add_path_to_history(path);
     model().set_root_path(path);
 }
 
@@ -223,7 +239,6 @@ void DirectoryView::set_status_message(const StringView& message)
 void DirectoryView::open_parent_directory()
 {
     auto path = String::format("%s/..", model().root_path().characters());
-    add_path_to_history(path);
     model().set_root_path(path);
 }
 

Applications/FileManager/DirectoryView.h

@@ -55,6 +55,7 @@ public:
     Function<void(const GUI::AbstractView&, const GUI::ModelIndex&, const GUI::DropEvent&)> on_drop;
     Function<void(const StringView&)> on_status_message;
     Function<void(int done, int total)> on_thumbnail_progress;
+    Function<void(int error, const char* error_string, bool quit)> on_error;
 
     enum ViewMode {
         Invalid,

Applications/FileManager/main.cpp

@@ -588,6 +588,14 @@ int run_in_windowed_mode(RefPtr<Core::ConfigFile> config, String initial_locatio
         go_back_action->set_enabled(directory_view.path_history_position() > 0);
     };
 
+    directory_view.on_error = [&](int, const char* error_string, bool quit) {
+        auto error_message = String::format("Could not read directory: %s", error_string);
+        GUI::MessageBox::show(error_message, "File Manager", GUI::MessageBox::Type::Error);
+
+        if (quit)
+            exit(1);
+    };
+
     directory_view.on_status_message = [&](const StringView& message) {
         statusbar.set_text(message);
     };