Use key files for tracking widget states.

Each EShellView now maintains a GKeyFile for recording disposable widget
state such as tree view path expansion, scroll bar positions, combo box
selections, etc.  The EShellView records changes to the key file to
~/.evolution/<shell-backend>/config/state, and automatically restores
the GKeyFile at startup.

Currently only the mailer uses the key file, but it's intended to serve
all shell views.  It replaces the use of Camel "cmeta" files, as well as
"et-expanded-*" and "folder-tree-expand-state.xml" files.

Also, the mailer's folder tree model now includes a column for tracking
which sidebar folders are expanded.  Folder tree widgets appearing in
dialog windows can copy the sidebar's expanded state using
em_folder_tree_clone_expanded().

1 files changed, 125 insertions, 0 deletions

diff --git a/shell/e-shell-view.c b/shell/e-shell-view.c
index cf89442c7c..d1ab1af4a4 100644
--- a/shell/e-shell-view.c
+++ b/shell/e-shell-view.c
@@ -33,10 +33,15 @@
 	(G_TYPE_INSTANCE_GET_PRIVATE \
 	((obj), E_TYPE_SHELL_VIEW, EShellViewPrivate))
 
+#define STATE_SAVE_TIMEOUT_SECONDS 3
+
 struct _EShellViewPrivate {
 
 	gpointer shell_window;  /* weak pointer */
 
+	GKeyFile *state_key_file;
+	guint state_save_source_id;
+
 	gchar *title;
 	gchar *view_id;
 	gint page_num;
@@ -118,6 +123,72 @@ shell_view_update_view_id (EShellView *shell_view,
 }
 
 static void
+shell_view_load_state (EShellView *shell_view)
+{
+	EShellBackend *shell_backend;
+	GKeyFile *key_file;
+	const gchar *config_dir;
+	gchar *filename;
+	GError *error = NULL;
+
+	shell_backend = e_shell_view_get_shell_backend (shell_view);
+	config_dir = e_shell_backend_get_config_dir (shell_backend);
+	filename = g_build_filename (config_dir, "state", NULL);
+
+	/* XXX Should do this asynchronously. */
+	key_file = shell_view->priv->state_key_file;
+	g_key_file_load_from_file (key_file, filename, 0, &error);
+
+	if (error == NULL)
+		goto exit;
+
+	if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
+		g_warning ("%s", error->message);
+
+	g_error_free (error);
+
+exit:
+	g_free (filename);
+}
+
+static void
+shell_view_save_state (EShellView *shell_view)
+{
+	EShellBackend *shell_backend;
+	GKeyFile *key_file;
+	const gchar *config_dir;
+	gchar *contents;
+	gchar *filename;
+	GError *error = NULL;
+
+	shell_backend = e_shell_view_get_shell_backend (shell_view);
+	config_dir = e_shell_backend_get_config_dir (shell_backend);
+	filename = g_build_filename (config_dir, "state", NULL);
+
+	/* XXX Should do this asynchronously. */
+	key_file = shell_view->priv->state_key_file;
+	contents = g_key_file_to_data (key_file, NULL, NULL);
+	g_file_set_contents (filename, contents, -1, &error);
+	g_free (contents);
+
+	if (error != NULL) {
+		g_warning ("%s", error->message);
+		g_error_free (error);
+	}
+
+	g_free (filename);
+}
+
+static gboolean
+shell_view_state_timeout_cb (EShellView *shell_view)
+{
+	shell_view_save_state (shell_view);
+	shell_view->priv->state_save_source_id = 0;
+
+	return FALSE;
+}
+
+static void
 shell_view_emit_toggled (EShellView *shell_view)
 {
 	g_signal_emit (shell_view, signals[TOGGLED], 0);
@@ -267,6 +338,13 @@ shell_view_dispose (GObject *object)
 
 	priv = E_SHELL_VIEW_GET_PRIVATE (object);
 
+	/* Expedite any pending state saves. */
+	if (priv->state_save_source_id > 0) {
+		g_source_remove (priv->state_save_source_id);
+		priv->state_save_source_id = 0;
+		shell_view_save_state (E_SHELL_VIEW (object));
+	}
+
 	if (priv->shell_window != NULL) {
 		g_object_remove_weak_pointer (
 			G_OBJECT (priv->shell_window), &priv->shell_window);
@@ -304,6 +382,8 @@ shell_view_finalize (GObject *object)
 
 	priv = E_SHELL_VIEW_GET_PRIVATE (object);
 
+	g_key_file_free (priv->state_key_file);
+
 	g_free (priv->title);
 	g_free (priv->view_id);
 
@@ -330,6 +410,8 @@ shell_view_constructed (GObject *object)
 
 	e_plugin_ui_register_manager (ui_manager, id, shell_view);
 
+	shell_view_load_state (shell_view);
+
 	/* Invoke factory methods. */
 
 	widget = class->new_shell_content (shell_view);
@@ -598,6 +680,7 @@ shell_view_init (EShellView *shell_view,
 	size_group = gtk_size_group_new (GTK_SIZE_GROUP_VERTICAL);
 
 	shell_view->priv = E_SHELL_VIEW_GET_PRIVATE (shell_view);
+	shell_view->priv->state_key_file = g_key_file_new ();
 	shell_view->priv->size_group = size_group;
 }
 
@@ -947,6 +1030,48 @@ e_shell_view_get_shell_taskbar (EShellView *shell_view)
 }
 
 /**
+ * e_shell_view_get_state_key_file:
+ * @shell_view: an #EShellView
+ *
+ * Returns the #GKeyFile holding widget state data for @shell_view.
+ *
+ * Returns: the #GKeyFile for @shell_view
+ **/
+GKeyFile *
+e_shell_view_get_state_key_file (EShellView *shell_view)
+{
+	g_return_val_if_fail (E_IS_SHELL_VIEW (shell_view), NULL);
+
+	return shell_view->priv->state_key_file;
+}
+
+/**
+ * e_shell_view_set_state_dirty:
+ * @shell_view: an #EShellView
+ *
+ * Marks the widget state data as modified (or "dirty") and schedules it
+ * to be saved to disk after a short delay.  The delay caps the frequency
+ * of saving to disk.
+ **/
+void
+e_shell_view_set_state_dirty (EShellView *shell_view)
+{
+	guint source_id;
+
+	g_return_if_fail (E_IS_SHELL_VIEW (shell_view));
+
+	/* If a timeout is already scheduled, do nothing. */
+	if (shell_view->priv->state_save_source_id > 0)
+		return;
+
+	source_id = g_timeout_add_seconds (
+		STATE_SAVE_TIMEOUT_SECONDS, (GSourceFunc)
+		shell_view_state_timeout_cb, shell_view);
+
+	shell_view->priv->state_save_source_id = source_id;
+}
+
+/**
  * e_shell_view_update_actions:
  * @shell_view: an #EShellView
  *