Monitor configuration files and emit added, remove and changed signals

Signed-off-by: David Zeuthen <davidz@redhat.com>

9 files changed, 645 insertions, 47 deletions

diff --git a/stc/stcitem.c b/stc/stcitem.c
index f8fa01e..a736429 100644
--- a/stc/stcitem.c
+++ b/stc/stcitem.c
@@ -56,6 +56,9 @@ struct _StcItem
 
   /* memoized */
   gchar **option_keys;
+
+  /* private */
+  gchar *sort_key;
 };
 
 typedef struct _StcItemClass StcItemClass;
@@ -63,8 +66,17 @@ typedef struct _StcItemClass StcItemClass;
 struct _StcItemClass
 {
   GObjectClass parent_class;
+  void (*changed) (StcItem *item);
+};
+
+enum
+{
+  CHANGED_SIGNAL,
+  LAST_SIGNAL
 };
 
+static guint signals[LAST_SIGNAL] = { 0 };
+
 G_DEFINE_TYPE (StcItem, stc_item, G_TYPE_OBJECT);
 
 static void
@@ -78,6 +90,8 @@ stc_item_finalize (GObject *object)
   g_hash_table_unref (item->options);
   g_free (item->option_keys);
 
+  g_free (item->sort_key);
+
   if (G_OBJECT_CLASS (stc_item_parent_class)->finalize)
     G_OBJECT_CLASS (stc_item_parent_class)->finalize (object);
 }
@@ -94,6 +108,22 @@ stc_item_class_init (StcItemClass *klass)
 
   gobject_class = G_OBJECT_CLASS (klass);
   gobject_class->finalize = stc_item_finalize;
+
+  /**
+   * StcItem::changed:
+   * @item: The item that changed.
+   *
+   * Emitted when an item changes.
+   */
+  signals[CHANGED_SIGNAL] = g_signal_new ("changed",
+                                          G_TYPE_FROM_CLASS (klass),
+                                          G_SIGNAL_RUN_LAST,
+                                          G_STRUCT_OFFSET (StcItemClass, changed),
+                                          NULL,
+                                          NULL,
+                                          g_cclosure_marshal_VOID__OBJECT,
+                                          G_TYPE_NONE,
+                                          0);
 }
 
 /**
@@ -160,7 +190,8 @@ _stc_item_new (StcItemType   type,
                const gchar  *id,
                const gchar  *target,
                const gchar  *nick_name,
-               GHashTable   *options)
+               GHashTable   *options,
+               const gchar  *sort_key)
 {
   StcItem *item;
 
@@ -171,10 +202,87 @@ _stc_item_new (StcItemType   type,
   item->nick_name = g_strdup (nick_name);
   item->type = type;
   item->options = g_hash_table_ref (options);
+  item->sort_key = g_strdup (sort_key);
 
   return item;
 }
 
+static gboolean
+hash_tables_equal (GHashTable *a, GHashTable *b)
+{
+  gboolean ret;
+  GHashTableIter iter;
+  const gchar *key;
+  const gchar *value;
+  const gchar *other_value;
+
+  ret = FALSE;
+
+  g_hash_table_iter_init (&iter, a);
+  while (g_hash_table_iter_next (&iter, (gpointer) &key, (gpointer) &value))
+    {
+      other_value = g_hash_table_lookup (b, key);
+      if (g_strcmp0 (value, other_value) != 0)
+        goto out;
+    }
+
+  g_hash_table_iter_init (&iter, b);
+  while (g_hash_table_iter_next (&iter, (gpointer) &key, (gpointer) &value))
+    {
+      other_value = g_hash_table_lookup (a, key);
+      if (g_strcmp0 (value, other_value) != 0)
+        goto out;
+    }
+
+  ret = TRUE;
+
+ out:
+  return ret;
+}
+
+gboolean
+_stc_item_update (StcItem *item, StcItem *other)
+{
+  gboolean changed;
+
+  g_return_val_if_fail (STC_IS_ITEM (item), FALSE);
+  g_return_val_if_fail (STC_IS_ITEM (other), FALSE);
+
+  changed = FALSE;
+
+  g_assert_cmpstr (item->id, ==, other->id);
+
+  if (g_strcmp0 (item->target, other->target) != 0)
+    {
+      g_free (item->target);
+      item->target = g_strdup (other->target);
+      changed = TRUE;
+    }
+
+  if (g_strcmp0 (item->nick_name, other->nick_name) != 0)
+    {
+      g_free (item->nick_name);
+      item->nick_name = g_strdup (other->nick_name);
+      changed = TRUE;
+    }
+
+  if (!hash_tables_equal (item->options, other->options))
+    {
+      g_hash_table_unref (item->options);
+      item->options = g_hash_table_ref (other->options);
+      changed = TRUE;
+    }
+
+  return changed;
+}
+
+const gchar *
+_stc_item_get_sort_key (StcItem *item)
+{
+  g_return_val_if_fail (STC_IS_ITEM (item), NULL);
+  return item->sort_key;
+}
+
 const gchar* const *
 stc_item_get_option_keys (StcItem *item)
 {
diff --git a/stc/stcmonitor.c b/stc/stcmonitor.c
index 8f0cc70..8fc5bf6 100644
--- a/stc/stcmonitor.c
+++ b/stc/stcmonitor.c
@@ -58,6 +58,9 @@ struct _StcMonitor
 
   GList *items;
   GHashTable *map_id_to_item;
+
+  GFileMonitor *conf_file_monitor;
+  GFileMonitor *conf_dir_monitor;
 };
 
 typedef struct _StcMonitorClass StcMonitorClass;
@@ -66,10 +69,12 @@ struct _StcMonitorClass
 {
   GObjectClass parent_class;
 
-  void (*error) (StcMonitor   *monitor,
-                 const gchar  *filename,
-                 gint          line_no,
-                 GError      **error);
+  void (*item_added)   (StcMonitor   *monitor,
+                        StcItem      *item);
+  void (*item_removed) (StcMonitor   *monitor,
+                        StcItem      *item);
+  void (*item_changed) (StcMonitor   *monitor,
+                        StcItem      *item);
 };
 
 enum
@@ -80,7 +85,29 @@ enum
   PROP_ERROR_HANDLER_USER_DATA
 };
 
-static GList *stc_monitor_load_all_files (StcMonitor   *monitor);
+enum
+{
+  ITEM_ADDED_SIGNAL,
+  ITEM_REMOVED_SIGNAL,
+  ITEM_CHANGED_SIGNAL,
+  LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
+static void stc_monitor_update (StcMonitor *monitor);
+
+static void on_conf_file_monitor_changed (GFileMonitor      *monitor,
+                                          GFile             *file,
+                                          GFile             *other_file,
+                                          GFileMonitorEvent  event_type,
+                                          gpointer           user_data);
+
+static void on_conf_dir_monitor_changed (GFileMonitor      *monitor,
+                                         GFile             *file,
+                                         GFile             *other_file,
+                                         GFileMonitorEvent  event_type,
+                                         gpointer           user_data);
 
 static void
 stc_monitor_emit_gerror (StcMonitor  *monitor,
@@ -104,6 +131,16 @@ stc_monitor_finalize (GObject *object)
 
   if (monitor->context != NULL)
     g_main_context_unref (monitor->context);
+  if (monitor->conf_file_monitor != NULL)
+    {
+      g_signal_handlers_disconnect_by_func (monitor->conf_file_monitor, G_CALLBACK (on_conf_file_monitor_changed), monitor);
+      g_object_unref (monitor->conf_file_monitor);
+    }
+  if (monitor->conf_dir_monitor != NULL)
+    {
+      g_signal_handlers_disconnect_by_func (monitor->conf_dir_monitor, G_CALLBACK (on_conf_dir_monitor_changed), monitor);
+      g_object_unref (monitor->conf_dir_monitor);
+    }
   g_free (monitor->config_dir);
   g_list_foreach (monitor->items, (GFunc) g_object_unref, NULL);
   g_list_free (monitor->items);
@@ -181,27 +218,57 @@ stc_monitor_init (StcMonitor *monitor)
   monitor->map_id_to_item = g_hash_table_new (g_str_hash, g_str_equal);
 }
 
-
 static void
 stc_monitor_constructed (GObject *object)
 {
   StcMonitor *monitor = STC_MONITOR (object);
-  GList *loaded_items;
-  GList *l;
+  GFile *file;
+  GError *error;
+  gchar *path;
 
   g_return_if_fail (STC_IS_MONITOR (monitor));
 
-  loaded_items = stc_monitor_load_all_files (monitor);
-
-  for (l = loaded_items; l != NULL; l = l->next)
+  path = g_strdup_printf ("%s/stc.conf", monitor->config_dir);
+  file = g_file_new_for_path (path);
+  error = NULL;
+  monitor->conf_file_monitor = g_file_monitor_file (file, G_FILE_MONITOR_SEND_MOVED, NULL, &error);
+  g_file_monitor_set_rate_limit (monitor->conf_file_monitor, 50);
+  if (monitor->conf_file_monitor == NULL)
     {
-      StcItem *item = STC_ITEM (l->data);
-      /* TODO: check if we have item already - if so, update existing object */
-      monitor->items = g_list_append (monitor->items, g_object_ref (item));
-      g_hash_table_insert (monitor->map_id_to_item, (gpointer) stc_item_get_id (item), item);
+      stc_monitor_emit_gerror (monitor,
+                               path,
+                               -1,
+                               error);
+      g_error_free (error);
     }
-  g_list_foreach (loaded_items, (GFunc) g_object_unref, NULL);
-  g_list_free (loaded_items);
+  g_signal_connect (monitor->conf_file_monitor,
+                    "changed",
+                    G_CALLBACK (on_conf_file_monitor_changed),
+                    monitor);
+  g_object_unref (file);
+  g_free (path);
+
+  path = g_strdup_printf ("%s/stc.conf.d", monitor->config_dir);
+  file = g_file_new_for_path (path);
+  error = NULL;
+  monitor->conf_dir_monitor = g_file_monitor_directory (file, G_FILE_MONITOR_SEND_MOVED, NULL, &error);
+  g_file_monitor_set_rate_limit (monitor->conf_dir_monitor, 50);
+  if (monitor->conf_dir_monitor == NULL)
+    {
+      stc_monitor_emit_gerror (monitor,
+                               path,
+                               -1,
+                               error);
+      g_error_free (error);
+    }
+  g_signal_connect (monitor->conf_dir_monitor,
+                    "changed",
+                    G_CALLBACK (on_conf_dir_monitor_changed),
+                    monitor);
+  g_object_unref (file);
+  g_free (path);
+
+  stc_monitor_update (monitor);
 
   if (G_OBJECT_CLASS (stc_monitor_parent_class)->constructed)
     G_OBJECT_CLASS (stc_monitor_parent_class)->constructed (object);
@@ -263,6 +330,61 @@ stc_monitor_class_init (StcMonitorClass *klass)
                                                          G_PARAM_WRITABLE |
                                                          G_PARAM_CONSTRUCT_ONLY |
                                                          G_PARAM_STATIC_STRINGS));
+
+
+  /**
+   * StcMonitor::item-added:
+   * @monitor: The #StcMonitor emitting the signal.
+   * @item: The item that was added.
+   *
+   * Emitted when an item is added.
+   */
+  signals[ITEM_ADDED_SIGNAL] = g_signal_new ("item-added",
+                                             G_TYPE_FROM_CLASS (klass),
+                                             G_SIGNAL_RUN_LAST,
+                                             G_STRUCT_OFFSET (StcMonitorClass, item_added),
+                                             NULL,
+                                             NULL,
+                                             g_cclosure_marshal_VOID__OBJECT,
+                                             G_TYPE_NONE,
+                                             1,
+                                             STC_TYPE_ITEM);
+
+  /**
+   * StcMonitor::item-removed:
+   * @monitor: The #StcMonitor emitting the signal.
+   * @item: The item that was removed.
+   *
+   * Emitted when an item is removed.
+   */
+  signals[ITEM_REMOVED_SIGNAL] = g_signal_new ("item-removed",
+                                               G_TYPE_FROM_CLASS (klass),
+                                               G_SIGNAL_RUN_LAST,
+                                               G_STRUCT_OFFSET (StcMonitorClass, item_removed),
+                                               NULL,
+                                               NULL,
+                                               g_cclosure_marshal_VOID__OBJECT,
+                                               G_TYPE_NONE,
+                                               1,
+                                               STC_TYPE_ITEM);
+
+  /**
+   * StcMonitor::item-changed:
+   * @monitor: The #StcMonitor emitting the signal.
+   * @item: The item that changed.
+   *
+   * Emitted when an item changes.
+   */
+  signals[ITEM_CHANGED_SIGNAL] = g_signal_new ("item-changed",
+                                               G_TYPE_FROM_CLASS (klass),
+                                               G_SIGNAL_RUN_LAST,
+                                               G_STRUCT_OFFSET (StcMonitorClass, item_changed),
+                                               NULL,
+                                               NULL,
+                                               g_cclosure_marshal_VOID__OBJECT,
+                                               G_TYPE_NONE,
+                                               1,
+                                               STC_TYPE_ITEM);
 }
 
 /**
@@ -422,6 +544,7 @@ stc_monitor_load_one_file (StcMonitor   *monitor,
       const gchar *item_id;
       gchar *target;
       gchar *nick_name;
+      gchar *sort_key;
       gchar *s;
       gchar **options_strv;
       StcItem *item;
@@ -430,6 +553,7 @@ stc_monitor_load_one_file (StcMonitor   *monitor,
       tokens = NULL;
       target = NULL;
       nick_name = NULL;
+      sort_key = NULL;
       options = NULL;
 
       tokens = g_strsplit (group, " ", 0);
@@ -534,13 +658,15 @@ stc_monitor_load_one_file (StcMonitor   *monitor,
       /* NickName is optional */
       nick_name = g_key_file_get_string (key_file, group, "NickName", NULL);
 
-      item = _stc_item_new (item_type, item_id, target, nick_name, options);
+      sort_key = g_strdup_printf ("%s:%s", path, item_id);
+      item = _stc_item_new (item_type, item_id, target, nick_name, options, sort_key);
       ret = g_list_prepend (ret, item);
 
     process_next_item:
       g_strfreev (tokens);
       g_free (target);
       g_free (nick_name);
+      g_free (sort_key);
       if (options != NULL)
         g_hash_table_unref (options);
     }
@@ -619,7 +745,7 @@ stc_monitor_load_all_files (StcMonitor *monitor)
   paths = g_ptr_array_new ();
   g_ptr_array_add (paths, g_strdup_printf ("%s/stc.conf", monitor->config_dir));
 
-  dir_path = g_strdup_printf ("%s/stc.d", monitor->config_dir);
+  dir_path = g_strdup_printf ("%s/stc.conf.d", monitor->config_dir);
   error = NULL;
   dir = g_dir_open (dir_path, 0, &error);
   if (error != NULL)
@@ -683,6 +809,127 @@ stc_monitor_load_all_files (StcMonitor *monitor)
   return ret;
 }
 
+static gint
+_item_cmp_func (gconstpointer a,
+                gconstpointer b)
+{
+  StcItem *ia;
+  StcItem *ib;
+
+  ia = STC_ITEM ((gpointer) a);
+  ib = STC_ITEM ((gpointer) b);
+
+  return g_strcmp0 (_stc_item_get_sort_key (ia), _stc_item_get_sort_key (ib));
+}
+
+static void
+stc_monitor_update (StcMonitor *monitor)
+{
+  GList *loaded_items;
+  GList *l;
+  GList *ll;
+  GList *items_changed;
+  GList *items_added;
+  GList *items_removed;
+  GHashTable *loaded_items_ids;
+
+  items_changed = NULL;
+  items_added = NULL;
+  items_removed = NULL;
+
+  loaded_items_ids = g_hash_table_new (g_str_hash, g_str_equal);
+
+  /* add/change items */
+  loaded_items = stc_monitor_load_all_files (monitor);
+  for (l = loaded_items; l != NULL; l = l->next)
+    {
+      StcItem *item = STC_ITEM (l->data);
+      StcItem *existing_item;
+
+      existing_item = g_hash_table_lookup (monitor->map_id_to_item, stc_item_get_id (item));
+      if (existing_item != NULL)
+        {
+          if (_stc_item_update (existing_item, item))
+            {
+              items_changed = g_list_prepend (items_changed, g_object_ref (existing_item));
+            }
+        }
+      else
+        {
+          monitor->items = g_list_append (monitor->items, g_object_ref (item));
+          g_hash_table_insert (monitor->map_id_to_item, (gpointer) stc_item_get_id (item), item);
+          items_added = g_list_prepend (items_added, g_object_ref (item));
+        }
+
+      g_hash_table_insert (loaded_items_ids, (gpointer) stc_item_get_id (item), GUINT_TO_POINTER (1));
+    }
+  /* remove items that wasn't loaded this time around */
+  for (l = monitor->items; l != NULL; l = ll)
+    {
+      StcItem *item = STC_ITEM (l->data);
+      ll = l->next;
+      if (g_hash_table_lookup (loaded_items_ids, stc_item_get_id (item)) == NULL)
+        {
+          /* item was removed */
+          items_removed = g_list_prepend (items_removed, g_object_ref (item));
+          monitor->items = g_list_delete_link (monitor->items, l);
+          g_object_unref (item);
+        }
+    }
+  g_hash_table_unref (loaded_items_ids);
+  g_list_foreach (loaded_items, (GFunc) g_object_unref, NULL);
+  g_list_free (loaded_items);
+
+  /* make the items appear in the order they were declared */
+  monitor->items = g_list_sort (monitor->items, _item_cmp_func);
+
+  /* emit signals only when our monitor object has been completely updated */
+  for (l = items_removed; l != NULL; l = l->next)
+    {
+      StcItem *item = STC_ITEM (l->data);
+      g_signal_emit (monitor, signals[ITEM_REMOVED_SIGNAL], 0, item);
+      g_object_unref (item);
+    }
+  g_list_free (items_removed);
+  for (l = items_added; l != NULL; l = l->next)
+    {
+      StcItem *item = STC_ITEM (l->data);
+      g_signal_emit (monitor, signals[ITEM_ADDED_SIGNAL], 0, item);
+      g_object_unref (item);
+    }
+  g_list_free (items_added);
+  for (l = items_changed; l != NULL; l = l->next)
+    {
+      StcItem *item = STC_ITEM (l->data);
+      g_signal_emit (monitor, signals[ITEM_CHANGED_SIGNAL], 0, item);
+      g_signal_emit_by_name (item, "changed");
+      g_object_unref (item);
+    }
+  g_list_free (items_changed);
+}
+
+static void
+on_conf_file_monitor_changed (GFileMonitor      *monitor,
+                              GFile             *file,
+                              GFile             *other_file,
+                              GFileMonitorEvent  event_type,
+                              gpointer           user_data)
+{
+  /* TODO: this is a bit expensive since all config files are reloaded */
+  stc_monitor_update (STC_MONITOR (user_data));
+}
+
+static void
+on_conf_dir_monitor_changed (GFileMonitor      *monitor,
+                             GFile             *file,
+                             GFile             *other_file,
+                             GFileMonitorEvent  event_type,
+                             gpointer           user_data)
+{
+  /* TODO: this is a bit expensive since all config files are reloaded */
+  stc_monitor_update (STC_MONITOR (user_data));
+}
+
 static void
 stc_monitor_emit_gerror (StcMonitor  *monitor,
                          const gchar *filename,
diff --git a/stc/stcprivate.h b/stc/stcprivate.h
index f7325cb..f56021b 100644
--- a/stc/stcprivate.h
+++ b/stc/stcprivate.h
@@ -36,7 +36,12 @@ StcItem *_stc_item_new (StcItemType   type,
                         const gchar  *id,
                         const gchar  *target,
                         const gchar  *nick_name,
-                        GHashTable   *options);
+                        GHashTable   *options,
+                        const gchar  *sort_key);
+
+const gchar *_stc_item_get_sort_key (StcItem *item);
+
+gboolean _stc_item_update (StcItem *item, StcItem *other);
 
 G_END_DECLS
 
diff --git a/stc/test.c b/stc/test.c
index c3a7f04..9144bc8 100644
--- a/stc/test.c
+++ b/stc/test.c
@@ -20,8 +20,15 @@
 
 #include "config.h"
 
+#include <stdlib.h>
+#include <string.h>
+
+#include <glib/gstdio.h>
+
 #include "stc.h"
 
+static GMainLoop *loop = NULL;
+
 /* ---------------------------------------------------------------------------------------------------- */
 
 static const gchar *
@@ -134,8 +141,9 @@ test_stc_no_conf (void)
   monitor = stc_monitor_new_for_config_dir (SRCDIR "/nonexistant", on_error_append_str, str);
   g_assert_cmpstr (stc_monitor_get_config_dir (monitor), ==, SRCDIR "/nonexistant");
   g_object_unref (monitor);
+
   g_assert_cmpstr (str->str, ==,
-                   SRCDIR "/nonexistant/stc.d: Error opening directory '" SRCDIR "/nonexistant/stc.d': No such file or directory (g-file-error-quark, 4)\n"
+                   SRCDIR "/nonexistant/stc.conf.d: Error opening directory '" SRCDIR "/nonexistant/stc.conf.d': No such file or directory (g-file-error-quark, 4)\n"
                    SRCDIR "/nonexistant/stc.conf: No such file or directory (g-file-error-quark, 4)\n"
                    );
   g_string_free (str, TRUE);
@@ -159,7 +167,7 @@ test_stc_semi_valid_conf (void)
                    SRCDIR "/testdata/semi_valid_conf/stc.conf: Invalid item identifer `with-dash' in group `Filesystem with-dash'. Only characters in [a-zA-Z0-9_] are supported. (stc-error-quark, 1)\n"
                    SRCDIR "/testdata/semi_valid_conf/stc.conf: Error parsing group name `Filesystem with space' (stc-error-quark, 1)\n"
                    SRCDIR "/testdata/semi_valid_conf/stc.conf: Element 0 of Options, `foo', for item foo of type MDRaid is malformed (no equal sign found). (stc-error-quark, 1)\n"
-                   SRCDIR "/testdata/semi_valid_conf/stc.d/91.conf: Encountered item with duplicate id `multiple_instances_same_id'. Ignoring previous items. (stc-error-quark, 2)\n"
+                   SRCDIR "/testdata/semi_valid_conf/stc.conf.d/91.conf: Encountered item with duplicate id `multiple_instances_same_id'. Ignoring previous items. (stc-error-quark, 2)\n"
                    );
   str2 = g_string_new (NULL);
   items = stc_monitor_get_items (monitor);
@@ -169,6 +177,30 @@ test_stc_semi_valid_conf (void)
       item_append_str (item, str2);
     }
   g_assert_cmpstr (str2->str, ==,
+                   "id         `in_pri_10'\n"
+                   "target     `Device=/dev/sda'\n"
+                   "nick-name  `(none)'\n"
+                   "type        filesystem\n"
+                   "options     (none)\n"
+                   "\n"
+                   "id         `in_pri_50'\n"
+                   "target     `Device=/dev/sda'\n"
+                   "nick-name  `(none)'\n"
+                   "type        filesystem\n"
+                   "options     (none)\n"
+                   "\n"
+                   "id         `in_pri_90'\n"
+                   "target     `Device=/dev/sda'\n"
+                   "nick-name  `(none)'\n"
+                   "type        filesystem\n"
+                   "options     (none)\n"
+                   "\n"
+                   "id         `multiple_instances_same_id'\n"
+                   "target     `Device=/dev/multiple_instances_same_id/second'\n"
+                   "nick-name  `(none)'\n"
+                   "type        filesystem\n"
+                   "options     (none)\n"
+                   "\n"
                    "id         `BigStorage'\n"
                    "target     `Device=/dev/disk/md-uuid-01234:56789'\n"
                    "nick-name  `BigStorage'\n"
@@ -193,30 +225,6 @@ test_stc_semi_valid_conf (void)
                    "nick-name  `My Secret Stuff (Encrypted)'\n"
                    "type        luks\n"
                    "options     LUKS:password -> `xyz123'\n"
-                   "\n"
-                   "id         `in_pri_10'\n"
-                   "target     `Device=/dev/sda'\n"
-                   "nick-name  `(none)'\n"
-                   "type        filesystem\n"
-                   "options     (none)\n"
-                   "\n"
-                   "id         `in_pri_50'\n"
-                   "target     `Device=/dev/sda'\n"
-                   "nick-name  `(none)'\n"
-                   "type        filesystem\n"
-                   "options     (none)\n"
-                   "\n"
-                   "id         `in_pri_90'\n"
-                   "target     `Device=/dev/sda'\n"
-                   "nick-name  `(none)'\n"
-                   "type        filesystem\n"
-                   "options     (none)\n"
-                   "\n"
-                   "id         `multiple_instances_same_id'\n"
-                   "target     `Device=/dev/multiple_instances_same_id/second'\n"
-                   "nick-name  `(none)'\n"
-                   "type        filesystem\n"
-                   "options     (none)\n"
                    "\n");
   g_string_free (str2, TRUE);
 
@@ -226,6 +234,231 @@ test_stc_semi_valid_conf (void)
 
 /* ---------------------------------------------------------------------------------------------------- */
 
+static void
+cleanup_dir (const gchar *dirname)
+{
+  gchar *command;
+
+  g_assert (g_str_has_prefix (dirname, "/tmp/stc-monitoring-test-"));
+  g_assert (strstr (dirname, "\"") == NULL);
+  command = g_strdup_printf ("rm -rf \"%s\"", dirname);
+  g_assert_cmpint (system (command), ==, 0);
+  g_free (command);
+}
+
+static gboolean
+on_timeout (gpointer user_data)
+{
+  g_assert_not_reached ();
+  return FALSE;
+}
+
+typedef enum
+{
+  _EVENT_ADDED,
+  _EVENT_REMOVED,
+  _EVENT_CHANGED
+} _Event;
+
+static void
+check_state (StcMonitor *monitor,
+             StcItem    *item,
+             gint        state,
+             _Event      event)
+{
+  switch (state)
+    {
+    case 0:
+      g_assert_cmpstr (stc_item_get_id (item), ==, "item1");
+      g_assert_cmpint (event, ==, _EVENT_ADDED);
+      break;
+
+    case 1:
+      g_assert_cmpstr (stc_item_get_id (item), ==, "item2");
+      g_assert_cmpint (event, ==, _EVENT_ADDED);
+      g_assert_cmpstr (stc_item_get_target (item), ==, "Device=/dev/sdc");
+      break;
+
+    case 2:
+      g_assert_cmpstr (stc_item_get_id (item), ==, "item1");
+      g_assert_cmpint (event, ==, _EVENT_REMOVED);
+      break;
+
+    case 3:
+      g_assert_cmpstr (stc_item_get_id (item), ==, "item2");
+      g_assert_cmpint (event, ==, _EVENT_CHANGED);
+      g_assert_cmpstr (stc_item_get_target (item), ==, "Device=/dev/sda");
+      break;
+
+    case 4:
+      g_assert_cmpstr (stc_item_get_id (item), ==, "item2");
+      g_assert_cmpint (event, ==, _EVENT_REMOVED);
+      break;
+
+    case 5:
+      g_assert_cmpstr (stc_item_get_id (item), ==, "item3");
+      g_assert_cmpint (event, ==, _EVENT_ADDED);
+      break;
+
+    default:
+      g_assert_not_reached ();
+      break;
+    }
+}
+
+
+static void
+on_item_added (StcMonitor *monitor,
+               StcItem    *item,
+               gpointer    user_data)
+{
+  gint *state = user_data;
+  check_state (monitor, item, *state, _EVENT_ADDED);
+  *state += 1;
+  g_main_loop_quit (loop);
+}
+
+static void
+on_item_removed (StcMonitor *monitor,
+                 StcItem    *item,
+                 gpointer    user_data)
+{
+  gint *state = user_data;
+  check_state (monitor, item, *state, _EVENT_REMOVED);
+  *state += 1;
+  g_main_loop_quit (loop);
+}
+
+static void
+on_item_changed (StcMonitor *monitor,
+                 StcItem    *item,
+                 gpointer    user_data)
+{
+  gint *state = user_data;
+  check_state (monitor, item, *state, _EVENT_CHANGED);
+  *state += 1;
+  g_main_loop_quit (loop);
+}
+
+static void
+test_stc_monitoring (void)
+{
+  gchar *dirname;
+  StcMonitor *monitor;
+  GError *error;
+  gboolean rc;
+  gchar *filename;
+  guint timeout_id;
+  gint state;
+
+  dirname = g_strdup ("/tmp/stc-monitoring-test-XXXXXX");
+  if (mkdtemp (dirname) == 0)
+    {
+      g_warning ("Error creating temp dir with template %s: %m", dirname);
+      g_assert_not_reached ();
+    }
+
+  monitor = stc_monitor_new_for_config_dir (dirname, NULL, NULL);
+  g_assert_cmpstr (stc_monitor_get_config_dir (monitor), ==, dirname);
+
+  /* main timeout */
+  timeout_id = g_timeout_add_seconds (30, on_timeout, NULL);
+
+  state = 0;
+  g_signal_connect (monitor,
+                    "item-added",
+                    G_CALLBACK (on_item_added),
+                    &state);
+  g_signal_connect (monitor,
+                    "item-removed",
+                    G_CALLBACK (on_item_removed),
+                    &state);
+  g_signal_connect (monitor,
+                    "item-changed",
+                    G_CALLBACK (on_item_changed),
+                    &state);
+
+  /* 0: check we get the item-added signal */
+  filename = g_strdup_printf ("%s/stc.conf", dirname);
+  error = NULL;
+  rc = g_file_set_contents (filename,
+                            "[Filesystem item1]\n"
+                            "Device=/dev/sdb\n",
+                            -1,
+                            &error);
+  g_assert_no_error (error);
+  g_assert (rc);
+  g_free (filename);
+  if (state <= 0)
+    g_main_loop_run (loop);
+
+  /* 1: check we get the item-added signal (again) */
+  filename = g_strdup_printf ("%s/stc.conf", dirname);
+  error = NULL;
+  rc = g_file_set_contents (filename,
+                            "[Filesystem item1]\n"
+                            "Device=/dev/sdb\n"
+                            "\n"
+                            "[Filesystem item2]\n"
+                            "Device=/dev/sdc\n",
+                            -1,
+                            &error);
+  g_assert_no_error (error);
+  g_assert (rc);
+  g_free (filename);
+  if (state <= 1)
+    g_main_loop_run (loop);
+
+  /* 2: check we get the item-removed signal */
+  filename = g_strdup_printf ("%s/stc.conf", dirname);
+  error = NULL;
+  rc = g_file_set_contents (filename,
+                            "[Filesystem item2]\n"
+                            "Device=/dev/sdc\n",
+                            -1,
+                            &error);
+  g_assert_no_error (error);
+  g_assert (rc);
+  g_free (filename);
+  if (state <= 2)
+    g_main_loop_run (loop);
+
+  /* 3: check we get the item-changed signal */
+  filename = g_strdup_printf ("%s/stc.conf", dirname);
+  error = NULL;
+  rc = g_file_set_contents (filename,
+                            "[Filesystem item2]\n"
+                            "Device=/dev/sda\n",
+                            -1,
+                            &error);
+  g_assert_no_error (error);
+  g_assert (rc);
+  g_free (filename);
+  if (state <= 3)
+    g_main_loop_run (loop);
+
+  /* 4+5: will give item-removed then item-added */
+  filename = g_strdup_printf ("%s/stc.conf", dirname);
+  error = NULL;
+  rc = g_file_set_contents (filename,
+                            "[Filesystem item3]\n"
+                            "Device=/dev/sda\n",
+                            -1,
+                            &error);
+  g_assert_no_error (error);
+  g_assert (rc);
+  g_free (filename);
+  if (state <= 5)
+    g_main_loop_run (loop);
+
+  g_object_unref (monitor);
+  cleanup_dir (dirname);
+
+  g_source_remove (timeout_id);
+}
+
+/* ---------------------------------------------------------------------------------------------------- */
+
 int
 main (int    argc,
       char **argv)
@@ -235,11 +468,16 @@ main (int    argc,
   g_type_init ();
   g_test_init (&argc, &argv, NULL);
 
+  loop = g_main_loop_new (NULL, FALSE);
+
   g_test_add_func ("/stc/basic", test_stc_basic);
   g_test_add_func ("/stc/no_conf", test_stc_no_conf);
   g_test_add_func ("/stc/semi_valid_conf", test_stc_semi_valid_conf);
+  g_test_add_func ("/stc/monitoring", test_stc_monitoring);
 
   ret = g_test_run();
 
+  g_main_loop_unref (loop);
+
   return ret;
 }
diff --git a/stc/testdata/semi_valid_conf/stc.d/10.conf b/stc/testdata/semi_valid_conf/stc.conf.d/10.conf
index 73b0c95..73b0c95 100644
--- a/stc/testdata/semi_valid_conf/stc.d/10.conf
+++ b/stc/testdata/semi_valid_conf/stc.conf.d/10.conf
diff --git a/stc/testdata/semi_valid_conf/stc.d/50.conf b/stc/testdata/semi_valid_conf/stc.conf.d/50.conf
index bad4e88..bad4e88 100644
--- a/stc/testdata/semi_valid_conf/stc.d/50.conf
+++ b/stc/testdata/semi_valid_conf/stc.conf.d/50.conf
diff --git a/stc/testdata/semi_valid_conf/stc.d/50.conf.wrong-extension b/stc/testdata/semi_valid_conf/stc.conf.d/50.conf.wrong-extension
index fae6617..fae6617 100644
--- a/stc/testdata/semi_valid_conf/stc.d/50.conf.wrong-extension
+++ b/stc/testdata/semi_valid_conf/stc.conf.d/50.conf.wrong-extension
diff --git a/stc/testdata/semi_valid_conf/stc.d/90.conf b/stc/testdata/semi_valid_conf/stc.conf.d/90.conf
index 15a3de1..15a3de1 100644
--- a/stc/testdata/semi_valid_conf/stc.d/90.conf
+++ b/stc/testdata/semi_valid_conf/stc.conf.d/90.conf
diff --git a/stc/testdata/semi_valid_conf/stc.d/91.conf b/stc/testdata/semi_valid_conf/stc.conf.d/91.conf
index a97db0f..a97db0f 100644
--- a/stc/testdata/semi_valid_conf/stc.d/91.conf
+++ b/stc/testdata/semi_valid_conf/stc.conf.d/91.conf