Add AsMonitor an abstraction on top of GFileMonitor

This is required to get sane semantics from GFileMonitor() when using temporary
files and atomic renames.

4 files changed, 839 insertions, 0 deletions

diff --git a/libappstream-glib/Makefile.am b/libappstream-glib/Makefile.am
index 9491b2b..5d8549f 100644
--- a/libappstream-glib/Makefile.am
+++ b/libappstream-glib/Makefile.am
@@ -99,6 +99,8 @@ libappstream_glib_la_SOURCES =					\
 	as-image-private.h					\
 	as-inf.c						\
 	as-inf.h						\
+	as-monitor.c						\
+	as-monitor.h						\
 	as-node.c						\
 	as-node-private.h					\
 	as-problem.c						\
diff --git a/libappstream-glib/as-monitor.c b/libappstream-glib/as-monitor.c
new file mode 100644
index 0000000..3501d62
--- /dev/null
+++ b/libappstream-glib/as-monitor.c
@@ -0,0 +1,505 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2015 Richard Hughes <richard@hughsie.com>
+ *
+ * Licensed under the GNU Lesser General Public License Version 2.1
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+/**
+ * SECTION:as-monitor
+ * @short_description: a hashed array monitor of applications
+ * @include: appstream-glib.h
+ * @stability: Stable
+ *
+ * This object will monitor a set of directories for changes.
+ *
+ * See also: #AsApp
+ */
+
+#include "config.h"
+
+#include "as-cleanup.h"
+#include "as-monitor.h"
+
+
+
+typedef struct _AsMonitorPrivate	AsMonitorPrivate;
+struct _AsMonitorPrivate
+{
+	GPtrArray		*array;		/* of GFileMonitor */
+	GPtrArray		*files;		/* of gchar* */
+	GPtrArray		*queue_add;	/* of gchar* */
+	GPtrArray		*queue_changed;	/* of gchar* */
+	GPtrArray		*queue_temp;	/* of gchar* */
+	guint			 pending_id;
+};
+
+G_DEFINE_TYPE_WITH_PRIVATE (AsMonitor, as_monitor, G_TYPE_OBJECT)
+
+enum {
+	SIGNAL_ADDED,
+	SIGNAL_REMOVED,
+	SIGNAL_CHANGED,
+	SIGNAL_LAST
+};
+
+static guint signals [SIGNAL_LAST] = { 0 };
+
+#define GET_PRIVATE(o) (as_monitor_get_instance_private (o))
+
+/**
+ * as_monitor_error_quark:
+ *
+ * Return value: An error quark.
+ *
+ * Since: 0.4.2
+ **/
+GQuark
+as_monitor_error_quark (void)
+{
+	static GQuark quark = 0;
+	if (!quark)
+		quark = g_quark_from_static_string ("AsMonitorError");
+	return quark;
+}
+
+/**
+ * as_monitor_finalize:
+ **/
+static void
+as_monitor_finalize (GObject *object)
+{
+	AsMonitor *monitor = AS_MONITOR (object);
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+
+	if (priv->pending_id)
+		g_source_remove (priv->pending_id);
+	g_ptr_array_unref (priv->array);
+	g_ptr_array_unref (priv->files);
+	g_ptr_array_unref (priv->queue_add);
+	g_ptr_array_unref (priv->queue_changed);
+	g_ptr_array_unref (priv->queue_temp);
+
+	G_OBJECT_CLASS (as_monitor_parent_class)->finalize (object);
+}
+
+/**
+ * as_monitor_init:
+ **/
+static void
+as_monitor_init (AsMonitor *monitor)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	priv->array = g_ptr_array_new_with_free_func ((GDestroyNotify) g_object_unref);
+	priv->files = g_ptr_array_new_with_free_func (g_free);
+	priv->queue_add = g_ptr_array_new_with_free_func (g_free);
+	priv->queue_changed = g_ptr_array_new_with_free_func (g_free);
+	priv->queue_temp = g_ptr_array_new_with_free_func (g_free);
+}
+
+/**
+ * as_monitor_class_init:
+ **/
+static void
+as_monitor_class_init (AsMonitorClass *klass)
+{
+	GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+	/**
+	 * AsMonitor::added:
+	 * @monitor: the #AsMonitor instance that emitted the signal
+	 * @filename: the filename
+	 *
+	 * The ::changed signal is emitted when a file has been added.
+	 *
+	 * Since: 0.4.2
+	 **/
+	signals [SIGNAL_ADDED] =
+		g_signal_new ("added",
+			      G_TYPE_FROM_CLASS (object_class), G_SIGNAL_RUN_LAST,
+			      G_STRUCT_OFFSET (AsMonitorClass, added),
+			      NULL, NULL, g_cclosure_marshal_VOID__STRING,
+			      G_TYPE_NONE, 1, G_TYPE_STRING);
+
+	/**
+	 * AsMonitor::removed:
+	 * @monitor: the #AsMonitor instance that emitted the signal
+	 * @filename: the filename
+	 *
+	 * The ::changed signal is emitted when a file has been removed.
+	 *
+	 * Since: 0.4.2
+	 **/
+	signals [SIGNAL_REMOVED] =
+		g_signal_new ("removed",
+			      G_TYPE_FROM_CLASS (object_class), G_SIGNAL_RUN_LAST,
+			      G_STRUCT_OFFSET (AsMonitorClass, removed),
+			      NULL, NULL, g_cclosure_marshal_VOID__STRING,
+			      G_TYPE_NONE, 1, G_TYPE_STRING);
+
+	/**
+	 * AsMonitor::changed:
+	 * @monitor: the #AsMonitor instance that emitted the signal
+	 * @filename: the filename
+	 *
+	 * The ::changed signal is emitted when a watched file has changed.
+	 *
+	 * Since: 0.4.2
+	 **/
+	signals [SIGNAL_CHANGED] =
+		g_signal_new ("changed",
+			      G_TYPE_FROM_CLASS (object_class), G_SIGNAL_RUN_LAST,
+			      G_STRUCT_OFFSET (AsMonitorClass, changed),
+			      NULL, NULL, g_cclosure_marshal_VOID__STRING,
+			      G_TYPE_NONE, 1, G_TYPE_STRING);
+
+	object_class->finalize = as_monitor_finalize;
+}
+
+/**
+ * _g_file_monitor_to_string:
+ */
+static const gchar *
+_g_file_monitor_to_string (GFileMonitorEvent ev)
+{
+	if (ev == G_FILE_MONITOR_EVENT_CHANGED)
+		return "CHANGED";
+	if (ev == G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT)
+		return "CHANGES_DONE_HINT";
+	if (ev == G_FILE_MONITOR_EVENT_DELETED)
+		return "DELETED";
+	if (ev == G_FILE_MONITOR_EVENT_CREATED)
+		return "CREATED";
+	if (ev == G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED)
+		return "ATTRIBUTE_CHANGED";
+	if (ev == G_FILE_MONITOR_EVENT_PRE_UNMOUNT)
+		return "PRE_UNMOUNT";
+	if (ev == G_FILE_MONITOR_EVENT_UNMOUNTED)
+		return "UNMOUNTED";
+	if (ev == G_FILE_MONITOR_EVENT_MOVED)
+		return "MOVED";
+	return NULL;
+}
+
+/**
+ * _g_ptr_array_str_find:
+ */
+static const gchar *
+_g_ptr_array_str_find (GPtrArray *array, const gchar *fn)
+{
+	guint i;
+	const gchar *tmp;
+	for (i = 0; i < array->len; i++) {
+		tmp = g_ptr_array_index (array, i);
+		if (g_strcmp0 (tmp, fn) == 0)
+			return fn;
+	}
+	return NULL;
+}
+
+/**
+ * _g_ptr_array_str_remove:
+ */
+static gboolean
+_g_ptr_array_str_remove (GPtrArray *array, const gchar *fn)
+{
+	guint i;
+	const gchar *tmp;
+	for (i = 0; i < array->len; i++) {
+		tmp = g_ptr_array_index (array, i);
+		if (g_strcmp0 (tmp, fn) == 0) {
+			g_ptr_array_remove_index_fast (array, i);
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
+
+/**
+ * _g_ptr_array_str_add:
+ */
+static void
+_g_ptr_array_str_add (GPtrArray *array, const gchar *fn)
+{
+	if (_g_ptr_array_str_find (array, fn) != NULL)
+		return;
+	g_ptr_array_add (array, g_strdup (fn));
+}
+
+/**
+ * as_monitor_emit_added:
+ */
+static void
+as_monitor_emit_added (AsMonitor *monitor, const gchar *filename)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	g_debug ("Emit ::added(%s)", filename);
+	g_signal_emit (monitor, signals[SIGNAL_ADDED], 0, filename);
+	_g_ptr_array_str_add (priv->files, filename);
+}
+
+/**
+ * as_monitor_emit_removed:
+ */
+static void
+as_monitor_emit_removed (AsMonitor *monitor, const gchar *filename)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	g_debug ("Emit ::removed(%s)", filename);
+	g_signal_emit (monitor, signals[SIGNAL_REMOVED], 0, filename);
+	_g_ptr_array_str_remove (priv->files, filename);
+}
+
+/**
+ * as_monitor_emit_changed:
+ */
+static void
+as_monitor_emit_changed (AsMonitor *monitor, const gchar *filename)
+{
+	g_debug ("Emit ::changed(%s)", filename);
+	g_signal_emit (monitor, signals[SIGNAL_CHANGED], 0, filename);
+}
+
+/**
+ * as_monitor_process_pending:
+ **/
+static void
+as_monitor_process_pending (AsMonitor *monitor)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	guint i;
+	const gchar *tmp;
+
+	/* stop the timer */
+	if (priv->pending_id) {
+		g_source_remove (priv->pending_id);
+		priv->pending_id = 0;
+	}
+
+	/* emit all the pending changed signals */
+	for (i = 0; i < priv->queue_changed->len; i++) {
+		tmp = g_ptr_array_index (priv->queue_changed, i);
+		as_monitor_emit_changed (monitor, tmp);
+	}
+	g_ptr_array_set_size (priv->queue_changed, 0);
+
+	/* emit all the pending add signals */
+	for (i = 0; i < priv->queue_add->len; i++) {
+		tmp = g_ptr_array_index (priv->queue_add, i);
+		/* did we atomically replace an existing file */
+		if (_g_ptr_array_str_find (priv->files, tmp) != NULL) {
+			g_debug ("detecting atomic replace of existing file");
+			as_monitor_emit_changed (monitor, tmp);
+		} else {
+			as_monitor_emit_added (monitor, tmp);
+		}
+	}
+	g_ptr_array_set_size (priv->queue_add, 0);
+}
+
+/**
+ * as_monitor_process_pending_trigger_cb:
+ **/
+static gboolean
+as_monitor_process_pending_trigger_cb (gpointer user_data)
+{
+	AsMonitor *monitor = AS_MONITOR (user_data);
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+
+	g_debug ("No CHANGES_DONE_HINT, catching in timeout");
+	as_monitor_process_pending (monitor);
+	priv->pending_id = 0;
+	return FALSE;
+}
+
+/**
+ * as_monitor_process_pending_trigger:
+ **/
+static void
+as_monitor_process_pending_trigger (AsMonitor *monitor)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	if (priv->pending_id)
+		g_source_remove (priv->pending_id);
+	priv->pending_id = g_timeout_add (800,
+					  as_monitor_process_pending_trigger_cb,
+					  monitor);
+}
+
+/**
+ * as_monitor_file_changed_cb:
+ *
+ * touch newfile      -> CREATED+CHANGED+ATTRIBUTE_CHANGED+CHANGES_DONE_HINT
+ *                       or, just CREATED
+ * touch newfile      -> ATTRIBUTE_CHANGED+CHANGES_DONE_HINT
+ * echo "1" > newfile -> CHANGED+CHANGES_DONE_HINT
+ * rm newfile         -> DELETED
+ **/
+static void
+as_monitor_file_changed_cb (GFileMonitor *mon,
+				 GFile *file, GFile *other_file,
+				 GFileMonitorEvent event_type,
+				 AsMonitor *monitor)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	const gchar *tmp;
+	gboolean is_temp;
+	_cleanup_free_ gchar *filename = NULL;
+	_cleanup_free_ gchar *filename_other = NULL;
+
+	/* get both filenames */
+	filename = g_file_get_path (file);
+	is_temp = !g_file_test (filename, G_FILE_TEST_EXISTS);
+	if (other_file != NULL)
+		filename_other = g_file_get_path (other_file);
+	g_debug ("modified: %s %s [%i]", filename,
+		_g_file_monitor_to_string (event_type), is_temp);
+
+	switch (event_type) {
+	case G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT:
+		as_monitor_process_pending (monitor);
+		break;
+	case G_FILE_MONITOR_EVENT_CREATED:
+		if (!is_temp) {
+			_g_ptr_array_str_add (priv->queue_add, filename);
+		} else {
+			_g_ptr_array_str_add (priv->queue_temp, filename);
+		}
+		/* file monitors do not send CHANGES_DONE_HINT */
+		as_monitor_process_pending_trigger (monitor);
+		break;
+	case G_FILE_MONITOR_EVENT_DELETED:
+		as_monitor_emit_removed (monitor, filename);
+		break;
+	case G_FILE_MONITOR_EVENT_CHANGED:
+		/* if the file is not pending and not a temp file, add */
+		if (_g_ptr_array_str_find (priv->queue_add, filename) == NULL &&
+		    _g_ptr_array_str_find (priv->queue_temp, filename) == NULL) {
+			_g_ptr_array_str_add (priv->queue_changed, filename);
+		}
+		break;
+	case G_FILE_MONITOR_EVENT_MOVED:
+		/* a temp file that was just created and atomically
+		 * renamed to its final destination */
+		tmp = _g_ptr_array_str_find (priv->queue_temp, filename);
+		if (tmp != NULL) {
+			g_debug ("detected atomic save, adding %s", filename_other);
+			g_ptr_array_remove_fast (priv->queue_temp, (gpointer) tmp);
+			if (_g_ptr_array_str_find (priv->files, filename_other) != NULL)
+				as_monitor_emit_changed (monitor, filename_other);
+			else
+				as_monitor_emit_added (monitor, filename_other);
+		} else {
+			g_debug ("detected rename, treating it as remove->add");
+			as_monitor_emit_removed (monitor, filename);
+			as_monitor_emit_added (monitor, filename_other);
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+/**
+ * as_monitor_add_directory:
+ **/
+gboolean
+as_monitor_add_directory (AsMonitor *monitor,
+			  const gchar *filename,
+			  GCancellable *cancellable,
+			  GError **error)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	const gchar *tmp;
+	_cleanup_object_unref_ GFileMonitor *mon = NULL;
+	_cleanup_object_unref_ GFile *file = NULL;
+	_cleanup_dir_close_ GDir *dir = NULL;
+
+	/* find the files already in the directory */
+	dir = g_dir_open (filename, 0, error);
+	if (dir == NULL)
+		return FALSE;
+	while ((tmp = g_dir_read_name (dir)) != NULL) {
+		_cleanup_free_ gchar *fn = NULL;
+		fn = g_build_filename (filename, tmp, NULL);
+		g_debug ("adding existing file: %s", fn);
+		_g_ptr_array_str_add (priv->files, fn);
+	}
+
+	/* create new file monitor */
+	file = g_file_new_for_path (filename);
+	mon = g_file_monitor_directory (file, G_FILE_MONITOR_SEND_MOVED,
+					cancellable, error);
+	if (mon == NULL)
+		return FALSE;
+	g_signal_connect (mon, "changed",
+			  G_CALLBACK (as_monitor_file_changed_cb), monitor);
+	g_ptr_array_add (priv->array, g_object_ref (mon));
+
+	return TRUE;
+}
+
+/**
+ * as_monitor_add_file:
+ **/
+gboolean
+as_monitor_add_file (AsMonitor *monitor,
+		     const gchar *filename,
+		     GCancellable *cancellable,
+		     GError **error)
+{
+	AsMonitorPrivate *priv = GET_PRIVATE (monitor);
+	_cleanup_object_unref_ GFile *file = NULL;
+	_cleanup_object_unref_ GFileMonitor *mon = NULL;
+
+	/* already watched */
+	if (_g_ptr_array_str_find (priv->files, filename) != NULL)
+		return TRUE;
+
+	/* create new file monitor */
+	file = g_file_new_for_path (filename);
+	mon = g_file_monitor_file (file, G_FILE_MONITOR_NONE,
+				   cancellable, error);
+	if (mon == NULL)
+		return FALSE;
+	g_signal_connect (mon, "changed",
+			  G_CALLBACK (as_monitor_file_changed_cb), monitor);
+	g_ptr_array_add (priv->array, g_object_ref (mon));
+
+	/* only add if actually exists */
+	if (g_file_test (filename, G_FILE_TEST_EXISTS))
+		_g_ptr_array_str_add (priv->files, filename);
+
+	return TRUE;
+}
+
+/**
+ * as_monitor_new:
+ *
+ * Creates a new #AsMonitor.
+ *
+ * Returns: (transfer full): a #AsMonitor
+ *
+ * Since: 0.4.2
+ **/
+AsMonitor *
+as_monitor_new (void)
+{
+	AsMonitor *monitor;
+	monitor = g_object_new (AS_TYPE_MONITOR, NULL);
+	return AS_MONITOR (monitor);
+}
diff --git a/libappstream-glib/as-monitor.h b/libappstream-glib/as-monitor.h
new file mode 100644
index 0000000..0906f09
--- /dev/null
+++ b/libappstream-glib/as-monitor.h
@@ -0,0 +1,97 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2015 Richard Hughes <richard@hughsie.com>
+ *
+ * Licensed under the GNU Lesser General Public License Version 2.1
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#if !defined (__APPSTREAM_GLIB_H) && !defined (AS_COMPILATION)
+#error "Only <appstream-glib.h> can be included directly."
+#endif
+
+#ifndef __AS_MONITOR_H
+#define __AS_MONITOR_H
+
+#include <glib-object.h>
+#include <gio/gio.h>
+
+#define AS_TYPE_MONITOR			(as_monitor_get_type())
+#define AS_MONITOR(obj)			(G_TYPE_CHECK_INSTANCE_CAST((obj), AS_TYPE_MONITOR, AsMonitor))
+#define AS_MONITOR_CLASS(cls)		(G_TYPE_CHECK_CLASS_CAST((cls), AS_TYPE_MONITOR, AsMonitorClass))
+#define AS_IS_MONITOR(obj)		(G_TYPE_CHECK_INSTANCE_TYPE((obj), AS_TYPE_MONITOR))
+#define AS_IS_MONITOR_CLASS(cls)	(G_TYPE_CHECK_CLASS_TYPE((cls), AS_TYPE_MONITOR))
+#define AS_MONITOR_GET_CLASS(obj)	(G_TYPE_INSTANCE_GET_CLASS((obj), AS_TYPE_MONITOR, AsMonitorClass))
+
+G_BEGIN_DECLS
+
+typedef struct _AsMonitor	AsMonitor;
+typedef struct _AsMonitorClass	AsMonitorClass;
+
+struct _AsMonitor
+{
+	GObject			parent;
+};
+
+struct _AsMonitorClass
+{
+	GObjectClass		parent_class;
+	void			(*added)	(AsMonitor	*monitor,
+						 const gchar	*filename);
+	void			(*removed)	(AsMonitor	*monitor,
+						 const gchar	*filename);
+	void			(*changed)	(AsMonitor	*monitor,
+						 const gchar	*filename);
+	/*< private >*/
+	void (*_as_reserved1)	(void);
+	void (*_as_reserved2)	(void);
+	void (*_as_reserved3)	(void);
+	void (*_as_reserved4)	(void);
+	void (*_as_reserved5)	(void);
+	void (*_as_reserved6)	(void);
+	void (*_as_reserved7)	(void);
+};
+
+/**
+ * AsMonitorError:
+ * @AS_MONITOR_ERROR_FAILED:			Generic failure
+ *
+ * The error type.
+ **/
+typedef enum {
+	AS_MONITOR_ERROR_FAILED,
+	/*< private >*/
+	AS_MONITOR_ERROR_LAST
+} AsMonitorError;
+
+#define	AS_MONITOR_ERROR			as_monitor_error_quark ()
+
+GType		 as_monitor_get_type		(void);
+AsMonitor	*as_monitor_new			(void);
+GQuark		 as_monitor_error_quark		(void);
+
+gboolean	 as_monitor_add_directory	(AsMonitor	*monitor,
+						 const gchar	*filename,
+						 GCancellable	*cancellable,
+						 GError		**error);
+gboolean	 as_monitor_add_file		(AsMonitor	*monitor,
+						 const gchar	*filename,
+						 GCancellable	*cancellable,
+						 GError		**error);
+
+G_END_DECLS
+
+#endif /* __AS_MONITOR_H */
diff --git a/libappstream-glib/as-self-test.c b/libappstream-glib/as-self-test.c
index 9e7dc96..a117c92 100644
--- a/libappstream-glib/as-self-test.c
+++ b/libappstream-glib/as-self-test.c
@@ -22,6 +22,7 @@
 #include "config.h"
 
 #include <glib.h>
+#include <glib/gstdio.h>
 #include <stdlib.h>
 
 #include "as-app-private.h"
@@ -31,6 +32,7 @@
 #include "as-icon-private.h"
 #include "as-image-private.h"
 #include "as-inf.h"
+#include "as-monitor.h"
 #include "as-node-private.h"
 #include "as-problem.h"
 #include "as-provide-private.h"
@@ -84,6 +86,237 @@ as_test_get_filename (const gchar *filename)
 	return g_strdup (full_tmp);
 }
 
+static GMainLoop *_test_loop = NULL;
+static guint _test_loop_timeout_id = 0;
+
+static gboolean
+as_test_hang_check_cb (gpointer user_data)
+{
+	g_main_loop_quit (_test_loop);
+	_test_loop_timeout_id = 0;
+	_test_loop = NULL;
+	return G_SOURCE_REMOVE;
+}
+
+/**
+ * as_test_loop_run_with_timeout:
+ **/
+static void
+as_test_loop_run_with_timeout (guint timeout_ms)
+{
+	g_assert (_test_loop_timeout_id == 0);
+	g_assert (_test_loop == NULL);
+	_test_loop = g_main_loop_new (NULL, FALSE);
+	_test_loop_timeout_id = g_timeout_add (timeout_ms, as_test_hang_check_cb, NULL);
+	g_main_loop_run (_test_loop);
+}
+
+/**
+ * as_test_loop_quit:
+ **/
+static void
+as_test_loop_quit (void)
+{
+	if (_test_loop_timeout_id > 0) {
+		g_source_remove (_test_loop_timeout_id);
+		_test_loop_timeout_id = 0;
+	}
+	if (_test_loop != NULL) {
+		g_main_loop_quit (_test_loop);
+		g_main_loop_unref (_test_loop);
+		_test_loop = NULL;
+	}
+}
+
+static void
+monitor_test_cb (AsMonitor *mon, const gchar *filename, guint *cnt)
+{
+	(*cnt)++;
+}
+
+static void
+as_test_monitor_dir_func (void)
+{
+	gboolean ret;
+	guint cnt_added = 0;
+	guint cnt_removed = 0;
+	guint cnt_changed = 0;
+	_cleanup_object_unref_ AsMonitor *mon = NULL;
+	_cleanup_error_free_ GError *error = NULL;
+	const gchar *tmpdir = "/tmp/monitor-test/usr/share/app-info/xmls";
+	_cleanup_free_ gchar *tmpfile = NULL;
+	_cleanup_free_ gchar *tmpfile_new = NULL;
+	_cleanup_free_ gchar *cmd_touch = NULL;
+
+	tmpfile = g_build_filename (tmpdir, "test.txt", NULL);
+	tmpfile_new = g_build_filename (tmpdir, "newtest.txt", NULL);
+	g_unlink (tmpfile);
+	g_unlink (tmpfile_new);
+
+	mon = as_monitor_new ();
+	g_signal_connect (mon, "added",
+			  G_CALLBACK (monitor_test_cb), &cnt_added);
+	g_signal_connect (mon, "removed",
+			  G_CALLBACK (monitor_test_cb), &cnt_removed);
+	g_signal_connect (mon, "changed",
+			  G_CALLBACK (monitor_test_cb), &cnt_changed);
+
+	/* add watch */
+	g_mkdir_with_parents (tmpdir, 0700);
+	ret = as_monitor_add_directory (mon, tmpdir, NULL, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+
+	/* touch file */
+	cmd_touch = g_strdup_printf ("touch %s", tmpfile);
+	ret = g_spawn_command_line_sync (cmd_touch, NULL, NULL, NULL, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 1);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* just change the mtime */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	ret = g_spawn_command_line_sync (cmd_touch, NULL, NULL, NULL, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 0);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* delete it */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	g_unlink (tmpfile);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 0);
+	g_assert_cmpint (cnt_removed, ==, 1);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* save a new file with temp copy */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	ret = g_file_set_contents (tmpfile, "foo", -1, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 1);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* modify file with temp copy */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	ret = g_file_set_contents (tmpfile, "bar", -1, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 0);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 1);
+
+	/* rename the file */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	g_rename (tmpfile, tmpfile_new);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 1);
+	g_assert_cmpint (cnt_removed, ==, 1);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	g_unlink (tmpfile);
+	g_unlink (tmpfile_new);
+}
+
+static void
+as_test_monitor_file_func (void)
+{
+	gboolean ret;
+	guint cnt_added = 0;
+	guint cnt_removed = 0;
+	guint cnt_changed = 0;
+	_cleanup_object_unref_ AsMonitor *mon = NULL;
+	_cleanup_error_free_ GError *error = NULL;
+	const gchar *tmpfile = "/tmp/one.txt";
+	const gchar *tmpfile_new = "/tmp/two.txt";
+	_cleanup_free_ gchar *cmd_touch = NULL;
+
+	g_unlink (tmpfile);
+	g_unlink (tmpfile_new);
+
+	mon = as_monitor_new ();
+	g_signal_connect (mon, "added",
+			  G_CALLBACK (monitor_test_cb), &cnt_added);
+	g_signal_connect (mon, "removed",
+			  G_CALLBACK (monitor_test_cb), &cnt_removed);
+	g_signal_connect (mon, "changed",
+			  G_CALLBACK (monitor_test_cb), &cnt_changed);
+
+	/* add a single file */
+	ret = as_monitor_add_file (mon, tmpfile, NULL, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+
+	/* touch file */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	cmd_touch = g_strdup_printf ("touch %s", tmpfile);
+	ret = g_spawn_command_line_sync (cmd_touch, NULL, NULL, NULL, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 1);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* just change the mtime */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	ret = g_spawn_command_line_sync (cmd_touch, NULL, NULL, NULL, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 0);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* delete it */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	g_unlink (tmpfile);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 0);
+	g_assert_cmpint (cnt_removed, ==, 1);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* save a new file with temp copy */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	ret = g_file_set_contents (tmpfile, "foo", -1, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 1);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 0);
+
+	/* modify file with temp copy */
+	cnt_added = cnt_removed = cnt_changed = 0;
+	ret = g_file_set_contents (tmpfile, "bar", -1, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+	as_test_loop_run_with_timeout (2000);
+	as_test_loop_quit ();
+	g_assert_cmpint (cnt_added, ==, 0);
+	g_assert_cmpint (cnt_removed, ==, 0);
+	g_assert_cmpint (cnt_changed, ==, 1);
+}
+
 static void
 as_test_tag_func (void)
 {
@@ -3802,6 +4035,8 @@ main (int argc, char **argv)
 	g_test_add_func ("/AppStream/utils{spdx-token}", as_test_utils_spdx_token_func);
 	g_test_add_func ("/AppStream/utils{install-filename}", as_test_utils_install_filename_func);
 	g_test_add_func ("/AppStream/utils{vercmp}", as_test_utils_vercmp_func);
+	g_test_add_func ("/AppStream/monitor{dir}", as_test_monitor_dir_func);
+	g_test_add_func ("/AppStream/monitor{file}", as_test_monitor_file_func);
 	g_test_add_func ("/AppStream/yaml", as_test_yaml_func);
 	g_test_add_func ("/AppStream/store", as_test_store_func);
 	g_test_add_func ("/AppStream/store{demote}", as_test_store_demote_func);