LibGUI: Add allowed file extensions to FileSystemModel

This allows FileSystemModel to take an optional list of allowed file
extensions which it will use to filter out all files that don't end
with that file extension.

The file extensions are set via `set_allowed_file_extensions` which has
a coresponding `get_allowed_file_extensions`.

1 files changed, 23 insertions, 3 deletions

diff --git a/Userland/Libraries/LibGUI/FileSystemModel.cpp b/Userland/Libraries/LibGUI/FileSystemModel.cpp
index 91d804d25e..545b4fda7c 100644
--- a/Userland/Libraries/LibGUI/FileSystemModel.cpp
+++ b/Userland/Libraries/LibGUI/FileSystemModel.cpp
@@ -120,10 +120,21 @@ void FileSystemModel::Node::traverse_if_needed()
 
         auto child = maybe_child.release_nonnull();
         total_size += child->size;
-        if (S_ISDIR(child->mode))
+        if (S_ISDIR(child->mode)) {
             directory_children.append(move(child));
-        else
-            file_children.append(move(child));
+        } else {
+            if (!m_model.m_allowed_file_extensions.has_value()) {
+                file_children.append(move(child));
+                continue;
+            }
+
+            for (auto& extension : *m_model.m_allowed_file_extensions) {
+                if (child_name.ends_with(DeprecatedString::formatted(".{}", extension))) {
+                    file_children.append(move(child));
+                    break;
+                }
+            }
+        }
     }
 
     m_children.extend(move(directory_children));
@@ -750,6 +761,15 @@ void FileSystemModel::set_should_show_dotfiles(bool show)
     invalidate();
 }
 
+void FileSystemModel::set_allowed_file_extensions(Optional<Vector<DeprecatedString>> const& allowed_file_extensions)
+{
+    if (m_allowed_file_extensions == allowed_file_extensions)
+        return;
+    m_allowed_file_extensions = allowed_file_extensions;
+
+    invalidate();
+}
+
 bool FileSystemModel::is_editable(ModelIndex const& index) const
 {
     if (!index.is_valid())