init hs project

1 files changed, 648 insertions, 0 deletions

diff --git a/csrc/launcher.c b/csrc/launcher.c
new file mode 100644
index 0000000..f4b34d8
--- /dev/null
+++ b/csrc/launcher.c
@@ -0,0 +1,648 @@
+#include "launcher.h"
+#include "launcher-item.h"
+#include "widgets/limit-container.h"
+#include <gtk4-layer-shell.h>
+#include <gdk/gdkkeysyms.h>
+#include <string.h>
+
+//
+// FoobarLauncher:
+//
+// A window allowing the user to quickly search for applications and launch them.
+//
+// Note that it should be possible to continue typing, even when the results list view is focused. Conversely, the arrow
+// keys can be used to select an item, even when the search input is focused.
+//
+
+struct _FoobarLauncher
+{
+	GtkWindow                   parent_instance;
+	gchar**                     search_terms;
+	GtkWidget*                  search_text;
+	GtkWidget*                  list_view;
+	GtkWidget*                  limit_container;
+	GtkFilterListModel*         filter_model;
+	GListStore*                 quick_answer_model;
+	GtkFlattenListModel*        flatten_model;
+	GtkSingleSelection*         selection_model;
+	FoobarApplicationService*   application_service;
+	FoobarQuickAnswerService*   quick_answer_service;
+	FoobarConfigurationService* configuration_service;
+	gulong                      config_handler_id;
+};
+
+static void     foobar_launcher_class_init               ( FoobarLauncherClass*   klass );
+static void     foobar_launcher_init                     ( FoobarLauncher*        self );
+static void     foobar_launcher_finalize                 ( GObject*               object );
+static void     foobar_launcher_handle_search_changed    ( GtkEditable*           editable,
+                                                           gpointer               userdata );
+static void     foobar_launcher_handle_search_activate   ( GtkText*               text,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_handle_search_key        ( GtkEventControllerKey* controller,
+                                                           guint                  keyval,
+                                                           guint                  keycode,
+                                                           GdkModifierType        state,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_handle_list_key          ( GtkEventControllerKey* controller,
+                                                           guint                  keyval,
+                                                           guint                  keycode,
+                                                           GdkModifierType        state,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_handle_window_key        ( GtkEventControllerKey* controller,
+                                                           guint                  keyval,
+                                                           guint                  keycode,
+                                                           GdkModifierType        state,
+                                                           gpointer               userdata );
+static void     foobar_launcher_handle_item_setup        ( GtkListItemFactory*    factory,
+                                                           GtkListItem*           list_item,
+                                                           gpointer               userdata );
+static void     foobar_launcher_handle_item_activate     ( GtkListView*           view,
+                                                           guint                  position,
+                                                           gpointer               userdata );
+static void     foobar_launcher_handle_config_change     ( GObject*               object,
+                                                           GParamSpec*            pspec,
+                                                           gpointer               userdata );
+static void     foobar_launcher_handle_show              ( GtkWidget*             widget,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_compute_icon_visible     ( GtkExpression*         expression,
+                                                           GIcon*                 icon,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_compute_label_visible    ( GtkExpression*         expression,
+                                                           gchar const*           label,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_compute_separator_visible( GtkExpression*         expression,
+                                                           guint                  item_count,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_filter_func              ( gpointer               item,
+                                                           gpointer               userdata );
+static gboolean foobar_launcher_is_navigation_key        ( guint                  keyval );
+
+G_DEFINE_FINAL_TYPE( FoobarLauncher, foobar_launcher, GTK_TYPE_WINDOW )
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Window Implementation
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Static initialization for the launcher.
+//
+void foobar_launcher_class_init( FoobarLauncherClass* klass )
+{
+	GObjectClass* object_klass = G_OBJECT_CLASS( klass );
+	object_klass->finalize = foobar_launcher_finalize;
+}
+
+//
+// Instance initialization for the launcher.
+//
+void foobar_launcher_init( FoobarLauncher* self )
+{
+	self->search_terms = g_new0( gchar*, 1 );
+
+	// Set up the search input and an event controller for auto-switching focus to the result list.
+
+	GtkEventController* search_controller = gtk_event_controller_key_new( );
+	g_signal_connect( search_controller, "key-pressed", G_CALLBACK( foobar_launcher_handle_search_key ), self );
+	g_signal_connect( search_controller, "key-released", G_CALLBACK( foobar_launcher_handle_search_key ), self );
+
+	self->search_text = gtk_text_new( );
+	gtk_text_set_placeholder_text( GTK_TEXT( self->search_text ), "Search…" );
+	gtk_widget_add_controller( self->search_text, search_controller );
+	gtk_widget_set_hexpand( self->search_text, TRUE );
+	g_signal_connect( self->search_text, "changed", G_CALLBACK( foobar_launcher_handle_search_changed ), self );
+	g_signal_connect( self->search_text, "activate", G_CALLBACK( foobar_launcher_handle_search_activate ), self );
+
+	GtkWidget* search_icon = gtk_image_new_from_icon_name( "fluent-search-symbolic" );
+
+	GtkWidget* search = gtk_box_new( GTK_ORIENTATION_HORIZONTAL, 0 );
+	gtk_box_append( GTK_BOX( search ), search_icon );
+	gtk_box_append( GTK_BOX( search ), self->search_text );
+	gtk_widget_add_css_class( search, "search" );
+
+	// Set up the separator (only shown if the results are not empty).
+
+	GtkWidget *separator = gtk_separator_new( GTK_ORIENTATION_HORIZONTAL );
+
+	// Set up the results list view and an event controller for auto-switching focus to the input.
+
+	GtkListItemFactory* item_factory = gtk_signal_list_item_factory_new( );
+	g_signal_connect( item_factory, "setup", G_CALLBACK( foobar_launcher_handle_item_setup ), NULL );
+
+	GtkCustomFilter* filter = gtk_custom_filter_new( foobar_launcher_filter_func, self, NULL );
+
+	self->filter_model = gtk_filter_list_model_new( NULL, GTK_FILTER( filter ) );
+
+	self->quick_answer_model = g_list_store_new( FOOBAR_TYPE_LAUNCHER_ITEM );
+
+	GListStore* flattened_models = g_list_store_new( G_TYPE_LIST_MODEL );
+	g_list_store_append( flattened_models, self->quick_answer_model );
+	g_list_store_append( flattened_models, self->filter_model );
+
+	self->flatten_model = gtk_flatten_list_model_new( G_LIST_MODEL( flattened_models ) );
+
+	self->selection_model = gtk_single_selection_new( G_LIST_MODEL( g_object_ref( self->flatten_model ) ) );
+
+	{
+		GtkExpression* list_expr = gtk_constant_expression_new( GTK_TYPE_FLATTEN_LIST_MODEL, self->flatten_model );
+		GtkExpression* count_expr = gtk_property_expression_new( GTK_TYPE_FLATTEN_LIST_MODEL, list_expr, "n-items" );
+		GtkExpression* visible_params[] = { count_expr };
+		GtkExpression* visible_expr = gtk_cclosure_expression_new(
+			G_TYPE_BOOLEAN,
+			NULL,
+			G_N_ELEMENTS( visible_params ),
+			visible_params,
+			G_CALLBACK( foobar_launcher_compute_separator_visible ),
+			NULL,
+			NULL );
+		gtk_expression_bind( visible_expr, separator, "visible", NULL );
+	}
+
+	GtkEventController* list_controller = gtk_event_controller_key_new( );
+	g_signal_connect( list_controller, "key-pressed", G_CALLBACK( foobar_launcher_handle_list_key ), self );
+	g_signal_connect( list_controller, "key-released", G_CALLBACK( foobar_launcher_handle_list_key ), self );
+
+	self->list_view = gtk_list_view_new( GTK_SELECTION_MODEL( g_object_ref( self->selection_model ) ), item_factory );
+	gtk_list_view_set_single_click_activate( GTK_LIST_VIEW( self->list_view ), TRUE );
+	gtk_scrollable_set_vscroll_policy( GTK_SCROLLABLE( self->list_view ), GTK_SCROLL_MINIMUM );
+	gtk_widget_add_controller( self->list_view, list_controller );
+	g_signal_connect( self->list_view, "activate", G_CALLBACK( foobar_launcher_handle_item_activate ), self );
+
+	GtkWidget* scrolled_window = gtk_scrolled_window_new( );
+	// XXX: Use GTK_POLICY_AUTOMATIC instead of GTK_POLICY_EXTERNAL once I figured out how to remove the minimum
+	//  height in this case. For now, no scrollbar is shown.
+	gtk_scrolled_window_set_policy( GTK_SCROLLED_WINDOW( scrolled_window ), GTK_POLICY_NEVER, GTK_POLICY_EXTERNAL );
+	gtk_scrolled_window_set_child( GTK_SCROLLED_WINDOW( scrolled_window ), self->list_view );
+	gtk_scrolled_window_set_propagate_natural_height( GTK_SCROLLED_WINDOW( scrolled_window ), TRUE );
+	gtk_widget_set_vexpand( scrolled_window, TRUE );
+
+	// Set up the layout.
+
+	GtkWidget* layout = gtk_box_new( GTK_ORIENTATION_VERTICAL, 0 );
+	gtk_box_append( GTK_BOX( layout ), search );
+	gtk_box_append( GTK_BOX( layout ), separator );
+	gtk_box_append( GTK_BOX( layout ), scrolled_window );
+
+	// Let the launcher take up space to accommodate the result list's natural height until the configured maximum
+	// height.
+
+	self->limit_container = foobar_limit_container_new( );
+	foobar_limit_container_set_child( FOOBAR_LIMIT_CONTAINER( self->limit_container ), layout );
+
+	// Set up the window, listening for the "Escape" key.
+
+	GtkEventController* window_controller = gtk_event_controller_key_new( );
+	g_signal_connect( window_controller, "key-released", G_CALLBACK( foobar_launcher_handle_window_key ), self );
+
+	gtk_window_set_child( GTK_WINDOW( self ), self->limit_container );
+	gtk_widget_add_controller( GTK_WIDGET( self ), window_controller );
+	gtk_window_set_title( GTK_WINDOW( self ), "Foobar Launcher" );
+	gtk_widget_add_css_class( GTK_WIDGET( self ), "launcher" );
+	gtk_layer_init_for_window( GTK_WINDOW( self ) );
+	gtk_layer_set_keyboard_mode( GTK_WINDOW( self ), GTK_LAYER_SHELL_KEYBOARD_MODE_EXCLUSIVE );
+	gtk_layer_set_namespace( GTK_WINDOW( self ), "foobar-launcher" );
+	gtk_layer_set_anchor( GTK_WINDOW( self ), GTK_LAYER_SHELL_EDGE_TOP, TRUE );
+	g_signal_connect( self, "show", G_CALLBACK( foobar_launcher_handle_show ), self );
+}
+
+//
+// Instance cleanup for the launcher.
+//
+void foobar_launcher_finalize( GObject* object )
+{
+	FoobarLauncher* self = (FoobarLauncher*)object;
+
+	g_clear_signal_handler( &self->config_handler_id, self->configuration_service );
+	g_clear_object( &self->filter_model );
+	g_clear_object( &self->quick_answer_model );
+	g_clear_object( &self->flatten_model );
+	g_clear_object( &self->selection_model );
+	g_clear_object( &self->application_service );
+	g_clear_object( &self->quick_answer_service );
+	g_clear_object( &self->configuration_service );
+	g_clear_pointer( &self->search_terms, g_strfreev );
+
+	G_OBJECT_CLASS( foobar_launcher_parent_class )->finalize( object );
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Public API
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Create a new launcher instance.
+//
+FoobarLauncher* foobar_launcher_new(
+	FoobarApplicationService*   application_service,
+	FoobarQuickAnswerService*   quick_answer_service,
+	FoobarConfigurationService* configuration_service )
+{
+	g_return_val_if_fail( FOOBAR_IS_APPLICATION_SERVICE( application_service ), NULL );
+	g_return_val_if_fail( FOOBAR_IS_QUICK_ANSWER_SERVICE( quick_answer_service ), NULL );
+	g_return_val_if_fail( FOOBAR_IS_CONFIGURATION_SERVICE( configuration_service ), NULL );
+
+	FoobarLauncher* self = g_object_new( FOOBAR_TYPE_LAUNCHER, NULL );
+	self->application_service = g_object_ref( application_service );
+	self->quick_answer_service = g_object_ref( quick_answer_service );
+	self->configuration_service = g_object_ref( configuration_service );
+
+	// Set up the result list view's source model.
+
+	GListModel* source_model = foobar_application_service_get_items( self->application_service );
+	gtk_filter_list_model_set_model( self->filter_model, g_object_ref( source_model ) );
+
+	// Apply the configuration and subscribe to changes.
+
+	FoobarConfiguration const* config = foobar_configuration_service_get_current( self->configuration_service );
+	foobar_launcher_apply_configuration( self, foobar_configuration_get_launcher( config ) );
+	self->config_handler_id = g_signal_connect(
+		self->configuration_service,
+		"notify::current",
+		G_CALLBACK( foobar_launcher_handle_config_change ),
+		self );
+
+	return self;
+}
+
+//
+// Apply the launcher configuration provided by the configuration service.
+//
+void foobar_launcher_apply_configuration(
+	FoobarLauncher*                    self,
+	FoobarLauncherConfiguration const* config )
+{
+	g_return_if_fail( FOOBAR_IS_LAUNCHER( self ) );
+	g_return_if_fail( config != NULL );
+
+	gtk_window_set_default_size( GTK_WINDOW( self ), foobar_launcher_configuration_get_width( config ), 2 );
+	gtk_layer_set_margin(
+		GTK_WINDOW( self ),
+		GTK_LAYER_SHELL_EDGE_TOP,
+		foobar_launcher_configuration_get_position( config ) );
+	foobar_limit_container_set_max_height(
+		FOOBAR_LIMIT_CONTAINER( self->limit_container ),
+		foobar_launcher_configuration_get_max_height( config ) );
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Signal Handlers
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Called when the user confirms the selection while the search input is focused.
+//
+// We forward the activation to the results list view.
+//
+void foobar_launcher_handle_search_activate(
+	GtkText* text,
+	gpointer userdata )
+{
+	(void)text;
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	guint selection = gtk_single_selection_get_selected( self->selection_model );
+	if ( selection != GTK_INVALID_LIST_POSITION )
+	{
+		gtk_widget_activate_action( self->list_view, "list.activate-item", "u", selection );
+	}
+}
+
+//
+// Called when the search query has changed.
+//
+// We update the tokenized search terms and then the result filter.
+//
+void foobar_launcher_handle_search_changed(
+	GtkEditable* editable,
+	gpointer     userdata )
+{
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	// Update quick answer.
+
+	g_autoptr(FoobarQuickAnswer) answer = foobar_quick_answer_service_query( self->quick_answer_service, gtk_editable_get_text( editable ) );
+	g_list_store_remove_all( self->quick_answer_model );
+	if (answer)
+	{
+		g_list_store_append(self->quick_answer_model, answer);
+	}
+
+	// Update filter.
+
+	GStrvBuilder* terms_builder = g_strv_builder_new( );
+	g_autofree gchar* query = g_strdup( gtk_editable_get_text( editable ) );
+	gchar* query_start = query;
+	gchar* save;
+	gchar* token;
+	while ( ( token = strtok_r( query_start, " \t", &save ) ) )
+	{
+		if ( *token ) { g_strv_builder_add( terms_builder, token ); }
+		query_start = NULL;
+	}
+
+	g_clear_pointer( &self->search_terms, g_strfreev );
+	self->search_terms = g_strv_builder_end( terms_builder );
+
+	GtkFilter* filter = gtk_filter_list_model_get_filter( self->filter_model );
+	gtk_filter_changed( filter, GTK_FILTER_CHANGE_DIFFERENT );
+}
+
+//
+// Handle keyboard events while the search input is focused.
+//
+// If this is a navigational key, the event is forwarded to the results list view.
+//
+gboolean foobar_launcher_handle_search_key(
+	GtkEventControllerKey* controller,
+	guint                  keyval,
+	guint                  keycode,
+	GdkModifierType        state,
+	gpointer               userdata )
+{
+	(void)keycode;
+	(void)state;
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	if ( foobar_launcher_is_navigation_key( keyval ) )
+	{
+		gtk_widget_grab_focus( self->list_view );
+		return gtk_event_controller_key_forward( controller, self->list_view );
+	}
+	else
+	{
+		return FALSE;
+	}
+}
+
+//
+// Handle keyboard events while the list view is focused.
+//
+// If this is not a navigational key, the event is forwarded to the search input, which is also focused.
+//
+gboolean foobar_launcher_handle_list_key(
+	GtkEventControllerKey* controller,
+	guint                  keyval,
+	guint                  keycode,
+	GdkModifierType        state,
+	gpointer               userdata )
+{
+	(void)keycode;
+	(void)state;
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	if ( foobar_launcher_is_navigation_key( keyval ) )
+	{
+		return FALSE;
+	}
+	else
+	{
+		gtk_text_grab_focus_without_selecting( GTK_TEXT( self->search_text ) );
+		return gtk_event_controller_key_forward( controller, self->search_text );
+	}
+}
+
+//
+// Handle general keyboard events for the window.
+//
+// This is used to allow the user to close the launcher by pressing the "Escape" key.
+//
+gboolean foobar_launcher_handle_window_key(
+	GtkEventControllerKey* controller,
+	guint                  keyval,
+	guint                  keycode,
+	GdkModifierType        state,
+	gpointer               userdata )
+{
+	(void)controller;
+	(void)keycode;
+	(void)state;
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	if ( keyval == GDK_KEY_Escape )
+	{
+		gtk_widget_set_visible( GTK_WIDGET( self ), FALSE );
+		return TRUE;
+	}
+	else
+	{
+		return FALSE;
+	}
+}
+
+//
+// Called by the result list view to create a widget for displaying an application item.
+//
+void foobar_launcher_handle_item_setup(
+	GtkListItemFactory* factory,
+	GtkListItem*        list_item,
+	gpointer            userdata )
+{
+	(void)factory;
+	(void)userdata;
+
+	// Set up layout.
+
+	GtkWidget* icon = gtk_image_new( );
+	gtk_widget_set_valign( icon, GTK_ALIGN_CENTER );
+	gtk_widget_add_css_class( icon, "icon" );
+
+	GtkWidget* title = gtk_label_new( NULL );
+	gtk_label_set_justify( GTK_LABEL( title ), GTK_JUSTIFY_LEFT );
+	gtk_label_set_xalign( GTK_LABEL( title ), 0 );
+	gtk_label_set_wrap( GTK_LABEL( title ), FALSE );
+	gtk_label_set_ellipsize( GTK_LABEL( title ), PANGO_ELLIPSIZE_END );
+	gtk_widget_add_css_class( title, "name" );
+
+	GtkWidget* description = gtk_label_new( NULL );
+	gtk_label_set_justify( GTK_LABEL( description ), GTK_JUSTIFY_LEFT );
+	gtk_label_set_xalign( GTK_LABEL( description ), 0 );
+	gtk_label_set_wrap( GTK_LABEL( description ), FALSE );
+	gtk_label_set_ellipsize( GTK_LABEL( description ), PANGO_ELLIPSIZE_END );
+	gtk_widget_add_css_class( description, "description" );
+
+	GtkWidget* column = gtk_box_new( GTK_ORIENTATION_VERTICAL, 0 );
+	gtk_widget_set_hexpand( column, TRUE );
+	gtk_widget_set_valign( column, GTK_ALIGN_CENTER );
+	gtk_box_append( GTK_BOX( column ), title );
+	gtk_box_append( GTK_BOX( column ), description );
+
+	GtkWidget* row = gtk_box_new( GTK_ORIENTATION_HORIZONTAL, 0 );
+	gtk_widget_add_css_class( row, "item" );
+	gtk_box_append( GTK_BOX( row ), icon );
+	gtk_box_append( GTK_BOX( row ), column );
+
+	gtk_list_item_set_child( list_item, row );
+
+	// Set up bindings.
+
+	{
+		GtkExpression* item_expr = gtk_property_expression_new( GTK_TYPE_LIST_ITEM, NULL, "item" );
+		GtkExpression* icon_expr = gtk_property_expression_new( FOOBAR_TYPE_LAUNCHER_ITEM, item_expr, "icon" );
+		gtk_expression_bind( gtk_expression_ref( icon_expr ), icon, "gicon", list_item );
+		GtkExpression* visible_params[] = { icon_expr };
+		GtkExpression* visible_expr = gtk_cclosure_expression_new(
+			G_TYPE_BOOLEAN,
+			NULL,
+			G_N_ELEMENTS( visible_params ),
+			visible_params,
+			G_CALLBACK( foobar_launcher_compute_icon_visible ),
+			NULL,
+			NULL );
+		gtk_expression_bind( visible_expr, icon, "visible", list_item );
+	}
+
+	{
+		GtkExpression* item_expr = gtk_property_expression_new( GTK_TYPE_LIST_ITEM, NULL, "item" );
+		GtkExpression* title_expr = gtk_property_expression_new( FOOBAR_TYPE_LAUNCHER_ITEM, item_expr, "title" );
+		gtk_expression_bind( title_expr, title, "label", list_item );
+	}
+
+	{
+		GtkExpression* item_expr = gtk_property_expression_new( GTK_TYPE_LIST_ITEM, NULL, "item" );
+		GtkExpression* description_expr = gtk_property_expression_new( FOOBAR_TYPE_LAUNCHER_ITEM, item_expr, "description" );
+		gtk_expression_bind( gtk_expression_ref( description_expr ), description, "label", list_item );
+		GtkExpression* visible_params[] = { description_expr };
+		GtkExpression* visible_expr = gtk_cclosure_expression_new(
+			G_TYPE_BOOLEAN,
+			NULL,
+			G_N_ELEMENTS( visible_params ),
+			visible_params,
+			G_CALLBACK( foobar_launcher_compute_label_visible ),
+			NULL,
+			NULL );
+		gtk_expression_bind( visible_expr, description, "visible", list_item );
+	}
+}
+
+//
+// Called by the result list view when an application was selected.
+//
+void foobar_launcher_handle_item_activate(
+	GtkListView* view,
+	guint        position,
+	gpointer     userdata )
+{
+	(void)view;
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	GListModel* list = G_LIST_MODEL( gtk_list_view_get_model( view ) );
+	FoobarLauncherItem* item = g_list_model_get_item( list, position );
+	foobar_launcher_item_activate( item );
+	gtk_widget_set_visible( GTK_WIDGET( self ), FALSE );
+}
+
+//
+// Signal handler called when the global configuration file has changed.
+//
+void foobar_launcher_handle_config_change(
+	GObject*    object,
+	GParamSpec* pspec,
+	gpointer    userdata )
+{
+	(void)object;
+	(void)pspec;
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	FoobarConfiguration const* config = foobar_configuration_service_get_current( self->configuration_service );
+	foobar_launcher_apply_configuration( self, foobar_configuration_get_launcher( config ) );
+}
+
+//
+// Called before the launcher is presented.
+//
+// This is used to reset the UI state.
+//
+void foobar_launcher_handle_show(
+	GtkWidget* widget,
+	gpointer   userdata )
+{
+	(void)widget;
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+
+	gtk_editable_set_text( GTK_EDITABLE( self->search_text ), "" );
+	if ( g_list_model_get_n_items( G_LIST_MODEL( self->selection_model ) ) > 0 )
+	{
+		gtk_list_view_scroll_to(
+			GTK_LIST_VIEW( self->list_view ),
+			0,
+			GTK_LIST_SCROLL_FOCUS | GTK_LIST_SCROLL_SELECT,
+			NULL );
+	}
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Value Converters
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Derive the visibility of an application icon from its value.
+//
+gboolean foobar_launcher_compute_icon_visible(
+	GtkExpression* expression,
+	GIcon*         icon,
+	gpointer       userdata )
+{
+	(void)expression;
+	(void)userdata;
+
+	return icon != NULL;
+}
+
+//
+// Derive the visibility of an application label from its value.
+//
+gboolean foobar_launcher_compute_label_visible(
+	GtkExpression* expression,
+	gchar const*   label,
+	gpointer       userdata )
+{
+	(void)expression;
+	(void)userdata;
+
+	return label != NULL;
+}
+
+//
+// Derive the visibility of the separator between search input and result list view from the number of results.
+//
+gboolean foobar_launcher_compute_separator_visible(
+	GtkExpression* expression,
+	guint          item_count,
+	gpointer       userdata )
+{
+	(void)expression;
+	(void)userdata;
+
+	return item_count > 0;
+}
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Helper Methods
+// ---------------------------------------------------------------------------------------------------------------------
+
+//
+// Match a result item against the current search query.
+//
+gboolean foobar_launcher_filter_func( gpointer item, gpointer userdata )
+{
+	FoobarLauncher* self = (FoobarLauncher*)userdata;
+	FoobarApplicationItem* app = (FoobarApplicationItem*)item;
+
+	return foobar_application_item_match( app, (gchar const* const*)self->search_terms );
+}
+
+//
+// Check if a key value is that of a navigation key (i.e., an arrow key).
+//
+gboolean foobar_launcher_is_navigation_key( guint keyval )
+{
+	switch ( keyval )
+	{
+		case GDK_KEY_Up:
+		case GDK_KEY_Down:
+		case GDK_KEY_Left:
+		case GDK_KEY_Right:
+			return TRUE;
+		default:
+			return FALSE;
+	}
+}