File Manager: Differentiate between navigation and rename errors

Adds a new on_rename_error handler and renames the old on_error handler
to on_directory_change_error in FileSystemModel. The on_rename_error
handler creates a MessageDialog with the error message.

Userland/Applications/FileManager/DirectoryView.cpp

@@ -214,7 +214,7 @@ const GUI::FileSystemModel::Node& DirectoryView::node(const GUI::ModelIndex& ind
 
 void DirectoryView::setup_model()
 {
-    m_model->on_error = [this](int, const char* error_string) {
+    m_model->on_directory_change_error = [this](int, const char* error_string) {
         auto failed_path = m_model->root_path();
         auto error_message = String::formatted("Could not read {}:\n{}", failed_path, error_string);
         m_error_label->set_text(error_message);
@@ -229,6 +229,10 @@ void DirectoryView::setup_model()
             on_path_change(failed_path, false, false);
     };
 
+    m_model->on_rename_error = [this](int, const char* error_string) {
+        GUI::MessageBox::show_error(window(), String::formatted("Unable to rename file: {}", error_string));
+    };
+
     m_model->on_complete = [this] {
         if (m_table_view)
             m_table_view->selection().clear();

Userland/Libraries/LibGUI/FileSystemModel.cpp

@@ -367,8 +367,8 @@ void FileSystemModel::set_root_path(String root_path)
     update();
 
     if (m_root->has_error()) {
-        if (on_error)
-            on_error(m_root->error(), m_root->error_string());
+        if (on_directory_change_error)
+            on_directory_change_error(m_root->error(), m_root->error_string());
     } else if (on_complete) {
         on_complete();
     }
@@ -676,8 +676,8 @@ void FileSystemModel::set_data(const ModelIndex& index, const Variant& data)
     auto new_full_path = String::formatted("{}/{}", dirname, data.to_string());
     int rc = rename(node.full_path().characters(), new_full_path.characters());
     if (rc < 0) {
-        if (on_error)
-            on_error(errno, strerror(errno));
+        if (on_rename_error)
+            on_rename_error(errno, strerror(errno));
     }
 }
 

Userland/Libraries/LibGUI/FileSystemModel.h

@@ -114,7 +114,8 @@ public:
 
     Function<void(int done, int total)> on_thumbnail_progress;
     Function<void()> on_complete;
-    Function<void(int error, const char* error_string)> on_error;
+    Function<void(int error, const char* error_string)> on_directory_change_error;
+    Function<void(int error, const char* error_string)> on_rename_error;
 
     virtual int tree_column() const override { return Column::Name; }
     virtual int row_count(const ModelIndex& = ModelIndex()) const override;