Use g_autoptr() in a lot more places

We started using this several months ago and nobody even noticed.

4 files changed, 155 insertions, 281 deletions

diff --git a/gusb/gusb-context.c b/gusb/gusb-context.c
index 2b8677a..8f0f5d6 100644
--- a/gusb/gusb-context.c
+++ b/gusb/gusb-context.c
@@ -17,6 +17,7 @@
 
 #include <libusb.h>
 
+#include "gusb-autocleanups.h"
 #include "gusb-context-private.h"
 #include "gusb-device-private.h"
 #include "gusb-util.h"
@@ -279,13 +280,13 @@ static void
 g_usb_context_add_device (GUsbContext	  *context,
 			  struct libusb_device *dev)
 {
-	GUsbDevice *device = NULL;
 	GUsbContextPrivate *priv = context->priv;
 	GUsbContextReplugHelper *replug_helper;
 	const gchar *platform_id;
 	guint8 bus;
 	guint8 address;
-	GError *error = NULL;
+	g_autoptr(GError) error = NULL;
+	g_autoptr(GUsbDevice) device = NULL;
 
 	/* does any existing device exist */
 	bus = libusb_get_bus_number (dev);
@@ -294,23 +295,21 @@ g_usb_context_add_device (GUsbContext	  *context,
 	if (priv->done_enumerate)
 		device = g_usb_context_find_by_bus_address (context, bus, address, NULL);
 	if (device != NULL)
-		goto out;
+		return;
 
 	/* add the device */
 	device = _g_usb_device_new (context, dev, &error);
 	if (device == NULL) {
 		g_debug ("There was a problem creating the device: %s",
 			 error->message);
-		g_error_free (error);
-		goto out;
+		return;
 	}
 
 	/* auto-open */
 	if (priv->flags & G_USB_CONTEXT_FLAGS_AUTO_OPEN_DEVICES) {
 		if (!_g_usb_device_open_internal (device, &error)) {
 			g_warning ("cannot open the device: %s", error->message);
-			g_error_free (error);
-			goto out;
+			return;
 		}
 	}
 
@@ -325,26 +324,23 @@ g_usb_context_add_device (GUsbContext	  *context,
 		g_object_unref (replug_helper->device);
 		replug_helper->device = g_object_ref (device);
 		g_main_loop_quit (replug_helper->loop);
-		goto out;
+		return;
 	}
 
 	/* emit signal */
 	g_usb_context_emit_device_add (context, device);
-out:
-	if (device != NULL)
-		g_object_unref (device);
 }
 
 static void
 g_usb_context_remove_device (GUsbContext	  *context,
 			     struct libusb_device *dev)
 {
-	GUsbDevice *device = NULL;
 	GUsbContextPrivate *priv = context->priv;
 	GUsbContextReplugHelper *replug_helper;
 	const gchar *platform_id;
 	guint8 bus;
 	guint8 address;
+	g_autoptr(GUsbDevice) device = NULL;
 
 	/* does any existing device exist */
 	bus = libusb_get_bus_number (dev);
@@ -363,13 +359,11 @@ g_usb_context_remove_device (GUsbContext	  *context,
 	replug_helper = g_hash_table_lookup (priv->dict_replug, platform_id);
 	if (replug_helper != NULL) {
 		g_debug ("%s is in replug, ignoring remove", platform_id);
-		goto out;
+		return;
 	}
 
 	/* emit signal */
 	g_usb_context_emit_device_remove (context, device);
-out:
-	g_object_unref (device);
 }
 
 typedef struct {
@@ -440,26 +434,22 @@ g_usb_context_hotplug_cb (struct libusb_context *ctx,
 static void
 g_usb_context_rescan (GUsbContext *context)
 {
-	GList *existing_devices = NULL;
-	GList *l;
-	GUsbDevice *device;
 	GUsbContextPrivate *priv = context->priv;
-	gboolean found;
-	guint i;
 	libusb_device **dev_list = NULL;
+	g_autoptr(GList) existing_devices = NULL;
 
 	/* copy to a context so we can remove from the array */
-	for (i = 0; i < priv->devices->len; i++) {
-		device = g_ptr_array_index (priv->devices, i);
+	for (guint i = 0; i < priv->devices->len; i++) {
+		GUsbDevice *device = g_ptr_array_index (priv->devices, i);
 		existing_devices = g_list_prepend (existing_devices, device);
 	}
 
 	/* look for any removed devices */
 	libusb_get_device_list (priv->ctx, &dev_list);
-	for (l = existing_devices; l != NULL; l = l->next) {
-		device = G_USB_DEVICE (l->data);
-		found = FALSE;
-		for (i = 0; dev_list != NULL && dev_list[i] != NULL; i++) {
+	for (GList *l = existing_devices; l != NULL; l = l->next) {
+		GUsbDevice *device = G_USB_DEVICE (l->data);
+		gboolean found = FALSE;
+		for (guint i = 0; dev_list != NULL && dev_list[i] != NULL; i++) {
 			if (libusb_get_bus_number (dev_list[i]) == g_usb_device_get_bus (device) &&
 			    libusb_get_device_address (dev_list[i]) == g_usb_device_get_address (device)) {
 				found = TRUE;
@@ -473,10 +463,9 @@ g_usb_context_rescan (GUsbContext *context)
 	}
 
 	/* add any devices not yet added (duplicates will be filtered */
-	for (i = 0; dev_list != NULL && dev_list[i] != NULL; i++)
+	for (guint i = 0; dev_list != NULL && dev_list[i] != NULL; i++)
 		g_usb_context_add_device (context, dev_list[i]);
 
-	g_list_free (existing_devices);
 	libusb_free_device_list (dev_list, 1);
 }
 
@@ -622,9 +611,10 @@ g_usb_context_enumerate (GUsbContext *context)
 	priv->done_enumerate = TRUE;
 
 	/* emit device-added signals before returning */
-	for (guint i = 0; i < priv->devices->len; i++)
+	for (guint i = 0; i < priv->devices->len; i++) {
 		g_signal_emit (context, signals[DEVICE_ADDED_SIGNAL], 0,
 			       g_ptr_array_index (priv->devices, i));
+	}
 
 	/* any queued up hotplug events are queued as idle handlers */
 }
@@ -849,8 +839,6 @@ g_usb_context_find_by_bus_address (GUsbContext  *context,
 				   GError      **error)
 {
 	GUsbContextPrivate *priv;
-	GUsbDevice *device = NULL;
-	guint i;
 
 	g_return_val_if_fail (G_USB_IS_CONTEXT (context), NULL);
 	g_return_val_if_fail (error == NULL || *error == NULL, NULL);
@@ -858,24 +846,19 @@ g_usb_context_find_by_bus_address (GUsbContext  *context,
 	priv = context->priv;
 
 	g_usb_context_enumerate (context);
-	for (i = 0; i < priv->devices->len; i++) {
-		GUsbDevice *curr = g_ptr_array_index (priv->devices, i);
-		if (g_usb_device_get_bus (curr) == bus &&
-		    g_usb_device_get_address (curr) == address) {
-			device = g_object_ref (curr);
-			break;
+	for (guint i = 0; i < priv->devices->len; i++) {
+		GUsbDevice *device = g_ptr_array_index (priv->devices, i);
+		if (g_usb_device_get_bus (device) == bus &&
+		    g_usb_device_get_address (device) == address) {
+			return  g_object_ref (device);
 		}
 	}
-
-	if (device == NULL) {
-		g_set_error (error,
-			     G_USB_DEVICE_ERROR,
-			     G_USB_DEVICE_ERROR_NO_DEVICE,
-			     "Failed to find device %04x:%04x",
-			     bus, address);
-	}
-
-	return device;
+	g_set_error (error,
+		     G_USB_DEVICE_ERROR,
+		     G_USB_DEVICE_ERROR_NO_DEVICE,
+		     "Failed to find device %04x:%04x",
+		     bus, address);
+	return NULL;
 }
 
 /**
@@ -896,8 +879,6 @@ g_usb_context_find_by_platform_id (GUsbContext *context,
 				   GError      **error)
 {
 	GUsbContextPrivate *priv;
-	GUsbDevice *device = NULL;
-	guint i;
 
 	g_return_val_if_fail (G_USB_IS_CONTEXT (context), NULL);
 	g_return_val_if_fail (error == NULL || *error == NULL, NULL);
@@ -905,23 +886,17 @@ g_usb_context_find_by_platform_id (GUsbContext *context,
 	priv = context->priv;
 
 	g_usb_context_enumerate (context);
-	for (i = 0; i < priv->devices->len; i++) {
-		GUsbDevice *curr = g_ptr_array_index (priv->devices, i);
-		if (g_strcmp0 (g_usb_device_get_platform_id (curr), platform_id) == 0) {
-			device = g_object_ref (curr);
-			break;
-		}
-	}
-
-	if (device == NULL) {
-		g_set_error (error,
-			     G_USB_DEVICE_ERROR,
-			     G_USB_DEVICE_ERROR_NO_DEVICE,
-			     "Failed to find device %s",
-			     platform_id);
+	for (guint i = 0; i < priv->devices->len; i++) {
+		GUsbDevice *device = g_ptr_array_index (priv->devices, i);
+		if (g_strcmp0 (g_usb_device_get_platform_id (device), platform_id) == 0)
+			return g_object_ref (device);
 	}
-
-	return device;
+	g_set_error (error,
+		     G_USB_DEVICE_ERROR,
+		     G_USB_DEVICE_ERROR_NO_DEVICE,
+		     "Failed to find device %s",
+		     platform_id);
+	return NULL;
 }
 
 /**
@@ -944,8 +919,6 @@ g_usb_context_find_by_vid_pid (GUsbContext  *context,
 			       GError      **error)
 {
 	GUsbContextPrivate *priv;
-	GUsbDevice *device = NULL;
-	guint i;
 
 	g_return_val_if_fail (G_USB_IS_CONTEXT (context), NULL);
 	g_return_val_if_fail (error == NULL || *error == NULL, NULL);
@@ -953,34 +926,29 @@ g_usb_context_find_by_vid_pid (GUsbContext  *context,
 	priv = context->priv;
 
 	g_usb_context_enumerate (context);
-	for (i = 0; i < priv->devices->len; i++) {
-		GUsbDevice *curr = g_ptr_array_index (priv->devices, i);
-		if (g_usb_device_get_vid (curr) == vid &&
-		    g_usb_device_get_pid (curr) == pid) {
-			device = g_object_ref (curr);
-			break;
+	for (guint i = 0; i < priv->devices->len; i++) {
+		GUsbDevice *device = g_ptr_array_index (priv->devices, i);
+		if (g_usb_device_get_vid (device) == vid &&
+		    g_usb_device_get_pid (device) == pid) {
+			return g_object_ref (device);
 		}
 	}
-
-	if (device == NULL) {
-		g_set_error (error,
-			     G_USB_DEVICE_ERROR,
-			     G_USB_DEVICE_ERROR_NO_DEVICE,
-			     "Failed to find device %04x:%04x",
-			     vid, pid);
-	}
-
-	return device;
+	g_set_error (error,
+		     G_USB_DEVICE_ERROR,
+		     G_USB_DEVICE_ERROR_NO_DEVICE,
+		     "Failed to find device %04x:%04x",
+		     vid, pid);
+	return NULL;
 }
+
 static gboolean
 g_usb_context_load_usb_ids (GUsbContext  *context,
 			    GError      **error)
 {
 	guint16 pid;
 	guint16 vid = 0x0000;
-	guint i;
-	gchar *data = NULL;
-	gchar **lines = NULL;
+	g_autofree gchar *data = NULL;
+	g_auto(GStrv) lines = NULL;
 
 	/* already loaded */
 	if (g_hash_table_size (context->priv->dict_usb_ids) > 0)
@@ -991,9 +959,7 @@ g_usb_context_load_usb_ids (GUsbContext  *context,
 		return FALSE;
 
 	lines = g_strsplit (data, "\n", -1);
-	g_free (data);
-
-	for (i = 0; lines[i] != NULL; i++) {
+	for (guint i = 0; lines[i] != NULL; i++) {
 		if (lines[i][0] == '#')
 			continue;
 
@@ -1022,8 +988,6 @@ g_usb_context_load_usb_ids (GUsbContext  *context,
 		}
 	}
 
-	g_strfreev (lines);
-
 	return TRUE;
 }
 
@@ -1045,7 +1009,7 @@ _g_usb_context_lookup_vendor (GUsbContext  *context,
 			      GError      **error)
 {
 	const gchar *tmp;
-	gchar *key = NULL;
+	g_autofree gchar *key = NULL;
 
 	g_return_val_if_fail (G_USB_IS_CONTEXT (context), NULL);
 	g_return_val_if_fail (error == NULL || *error == NULL, NULL);
@@ -1062,12 +1026,9 @@ _g_usb_context_lookup_vendor (GUsbContext  *context,
 			     G_USB_CONTEXT_ERROR,
 			     G_USB_CONTEXT_ERROR_INTERNAL,
 			     "failed to find vid %s", key);
-		g_free (key);
 		return NULL;
 	}
 
-	g_free (key);
-
 	return tmp;
 }
 
@@ -1091,7 +1052,7 @@ _g_usb_context_lookup_product (GUsbContext  *context,
 			       GError      **error)
 {
 	const gchar *tmp;
-	gchar *key = NULL;
+	g_autofree gchar *key = NULL;
 
 	g_return_val_if_fail (G_USB_IS_CONTEXT (context), NULL);
 	g_return_val_if_fail (error == NULL || *error == NULL, NULL);
@@ -1108,12 +1069,9 @@ _g_usb_context_lookup_product (GUsbContext  *context,
 			     G_USB_CONTEXT_ERROR,
 			     G_USB_CONTEXT_ERROR_INTERNAL,
 			     "failed to find vid %s", key);
-		g_free (key);
 		return NULL;
 	}
 
-	g_free (key);
-
 	return tmp;
 }
 
@@ -1144,6 +1102,8 @@ g_usb_context_replug_timeout_cb (gpointer user_data)
 	return FALSE;
 }
 
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GUsbContextReplugHelper, g_usb_context_replug_helper_free)
+
 /**
  * g_usb_context_wait_for_replug:
  * @context: a #GUsbContext
@@ -1167,10 +1127,9 @@ g_usb_context_wait_for_replug (GUsbContext *context,
 			       guint timeout_ms,
 			       GError **error)
 {
-	GUsbDevice *device_new = NULL;
 	GUsbContextPrivate *priv = context->priv;
-	GUsbContextReplugHelper *replug_helper;
 	const gchar *platform_id;
+	g_autoptr(GUsbContextReplugHelper) replug_helper = NULL;
 
 	g_return_val_if_fail (G_USB_IS_CONTEXT (context), NULL);
 
@@ -1200,12 +1159,9 @@ g_usb_context_wait_for_replug (GUsbContext *context,
 				     G_USB_CONTEXT_ERROR,
 				     G_USB_CONTEXT_ERROR_INTERNAL,
 				     "request timed out");
-		goto out;
+		return NULL;
 	}
-	device_new = g_object_ref (replug_helper->device);
-out:
-	g_usb_context_replug_helper_free (replug_helper);
-	return device_new;
+	return g_object_ref (replug_helper->device);
 }
 
 /**
diff --git a/gusb/gusb-device.c b/gusb/gusb-device.c
index 2f814ae..81f90ad 100644
--- a/gusb/gusb-device.c
+++ b/gusb/gusb-device.c
@@ -261,7 +261,7 @@ g_usb_device_initable_init (GInitable     *initable,
 
 	priv = device->priv;
 
-	if (!priv->device) {
+	if (priv->device == NULL) {
 		g_set_error_literal (error, G_USB_DEVICE_ERROR, G_USB_DEVICE_ERROR_INTERNAL,
 				     "Constructed without a libusb_device");
 		return FALSE;
@@ -469,7 +469,6 @@ g_usb_device_get_custom_index (GUsbDevice *device,
 	const struct libusb_interface_descriptor *ifp;
 	gint rc;
 	guint8 idx = 0x00;
-	guint i;
 	struct libusb_config_descriptor *config;
 
 	rc = libusb_get_active_config_descriptor (device->priv->device, &config);
@@ -477,7 +476,7 @@ g_usb_device_get_custom_index (GUsbDevice *device,
 		return 0x00;
 
 	/* find the right data */
-	for (i = 0; i < config->bNumInterfaces; i++) {
+	for (guint i = 0; i < config->bNumInterfaces; i++) {
 		ifp = &config->interface[i].altsetting[0];
 		if (ifp->bInterfaceClass != class_id)
 			continue;
@@ -530,7 +529,6 @@ g_usb_device_get_interface (GUsbDevice *device,
 	const struct libusb_interface_descriptor *ifp;
 	gint rc;
 	GUsbInterface *interface = NULL;
-	guint i;
 	struct libusb_config_descriptor *config;
 
 	g_return_val_if_fail (G_USB_IS_DEVICE (device), NULL);
@@ -541,7 +539,7 @@ g_usb_device_get_interface (GUsbDevice *device,
 		return NULL;
 
 	/* find the right data */
-	for (i = 0; i < config->bNumInterfaces; i++) {
+	for (guint i = 0; i < config->bNumInterfaces; i++) {
 		ifp = &config->interface[i].altsetting[0];
 		if (ifp->bInterfaceClass != class_id)
 			continue;
@@ -583,8 +581,6 @@ g_usb_device_get_interfaces (GUsbDevice *device, GError **error)
 {
 	const struct libusb_interface_descriptor *ifp;
 	gint rc;
-	guint i;
-	guint j;
 	struct libusb_config_descriptor *config;
 	GPtrArray *array = NULL;
 
@@ -597,9 +593,9 @@ g_usb_device_get_interfaces (GUsbDevice *device, GError **error)
 
 	/* get all interfaces */
 	array = g_ptr_array_new_with_free_func ((GDestroyNotify) g_object_unref);
-	for (i = 0; i < config->bNumInterfaces; i++) {
+	for (guint i = 0; i < config->bNumInterfaces; i++) {
 		GUsbInterface *interface = NULL;
-		for (j = 0; j < (guint) config->interface[i].num_altsetting; j++) {
+		for (guint j = 0; j < (guint) config->interface[i].num_altsetting; j++) {
 			ifp = &config->interface[i].altsetting[j];
 			interface = _g_usb_interface_new (ifp);
 			g_ptr_array_add (array, interface);
@@ -1705,20 +1701,17 @@ g_usb_device_get_children (GUsbDevice *device)
 	GPtrArray *children;
 	GUsbDevice *device_tmp;
 	GUsbDevicePrivate *priv = device->priv;
-	guint i;
-	GPtrArray *devices = NULL;
+	g_autoptr(GPtrArray) devices = NULL;
 
 	/* find any devices that have @device as a parent */
 	children = g_ptr_array_new_with_free_func ((GDestroyNotify) g_object_unref);
 	devices = g_usb_context_get_devices (priv->context);
-	for (i = 0; i < devices->len; i++) {
+	for (guint i = 0; i < devices->len; i++) {
 		device_tmp = g_ptr_array_index (devices, i);
 		if (priv->device == libusb_get_parent (device_tmp->priv->device))
 			g_ptr_array_add (children, g_object_ref (device_tmp));
 	}
 
-	g_ptr_array_unref (devices);
-
 	return children;
 }
 
diff --git a/gusb/gusb-self-test.c b/gusb/gusb-self-test.c
index 250176e..f078e1e 100644
--- a/gusb/gusb-self-test.c
+++ b/gusb/gusb-self-test.c
@@ -7,15 +7,16 @@
 
 #include "config.h"
 
+#include "gusb-autocleanups.h"
 #include "gusb-context-private.h"
 
 static void
 gusb_device_func (void)
 {
-	GError *error = NULL;
-	GPtrArray *array;
-	GUsbContext *ctx;
 	GUsbDevice *device;
+	g_autoptr(GError) error = NULL;
+	g_autoptr(GPtrArray) array = NULL;
+	g_autoptr(GUsbContext) ctx = NULL;
 
 #ifdef __FreeBSD__
 	g_test_skip ("Root hubs on FreeBSD have vid and pid set to zero");
@@ -35,16 +36,14 @@ gusb_device_func (void)
 
 	g_assert_cmpint (g_usb_device_get_vid (device), >, 0x0000);
 	g_assert_cmpint (g_usb_device_get_pid (device), >, 0x0000);
-
-	g_ptr_array_unref (array);
 }
 
 static void
 gusb_context_lookup_func (void)
 {
-	GUsbContext *ctx = NULL;
 	GError *error = NULL;
 	const gchar *tmp;
+	g_autoptr(GUsbContext) ctx = NULL;
 
 	ctx = g_usb_context_new (&error);
 	g_assert_no_error (error);
@@ -56,21 +55,17 @@ gusb_context_lookup_func (void)
 	tmp = _g_usb_context_lookup_product (ctx, 0x04d8, 0xf8da, &error);
 	g_assert_no_error (error);
 	g_assert_cmpstr (tmp, ==, "Hughski Ltd. ColorHug");
-	g_object_unref (ctx);
 }
 
 static void
 gusb_context_func (void)
 {
-	GUsbContext *ctx;
-	GError *error = NULL;
 	GPtrArray *array;
 	guint old_number_of_devices;
 	guint8 bus, address;
 	GUsbDevice *device;
-	gchar *manufacturer;
-	gchar *product;
-	guint i;
+	g_autoptr(GError) error = NULL;
+	g_autoptr(GUsbContext) ctx = NULL;
 
 #ifdef __FreeBSD__
 	g_test_skip ("Root hubs on FreeBSD have vid and pid set to zero");
@@ -91,7 +86,10 @@ gusb_context_func (void)
 
 	/* Print a list (also exercising various bits of g_usb_device) */
 	g_print ("\n");
-	for (i = 0; i < array->len; i++) {
+	for (guint i = 0; i < array->len; i++) {
+		g_autofree gchar *manufacturer = NULL;
+		g_autofree gchar *product = NULL;
+
 		device = G_USB_DEVICE (g_ptr_array_index (array, i));
 
 		g_assert_cmpint (g_usb_device_get_vid (device), >, 0x0000);
@@ -120,9 +118,6 @@ gusb_context_func (void)
 			 g_usb_device_get_pid (device),
 			 manufacturer ? manufacturer : "",
 			 product ? product : "");
-
-		g_free (manufacturer);
-		g_free (product);
 	}
 	g_ptr_array_unref (array);
 
@@ -155,20 +150,17 @@ gusb_context_func (void)
 			G_USB_DEVICE_ERROR,
 			G_USB_DEVICE_ERROR_NO_DEVICE);
 	g_assert (device == NULL);
-	g_clear_error (&error);
-
-	g_object_unref (ctx);
 }
 
 static void
 gusb_device_huey_func (void)
 {
-	GUsbContext *ctx;
-	GError *error = NULL;
-	GUsbDevice *device;
 	gboolean ret;
 	GCancellable *cancellable = NULL;
 	const gchar request[8] = { 0x0e, 'G', 'r', 'M', 'b', 'k', 'e', 'd' };
+	g_autoptr(GError) error = NULL;
+	g_autoptr(GUsbContext) ctx = NULL;
+	g_autoptr(GUsbDevice) device = NULL;
 
 	ctx = g_usb_context_new (&error);
 	g_assert_no_error (error);
@@ -185,8 +177,7 @@ gusb_device_huey_func (void)
 	    error->domain == G_USB_DEVICE_ERROR &&
 	    error->code == G_USB_DEVICE_ERROR_NO_DEVICE) {
 		g_print ("No device detected!\n");
-		g_error_free (error);
-		goto out;
+		return;
 	}
 	g_assert_no_error (error);
 	g_assert (device != NULL);
@@ -267,10 +258,6 @@ gusb_device_huey_func (void)
 	ret = g_usb_device_close (device, &error);
 	g_assert_no_error (error);
 	g_assert (ret);
-
-	g_object_unref (device);
-out:
-	g_object_unref (ctx);
 }
 
 typedef struct {
@@ -285,19 +272,17 @@ g_usb_device_print_data (const gchar  *title,
 			 const guchar *data,
 			 gsize	 length)
 {
-	guint i;
-
 	if (g_strcmp0 (title, "request") == 0)
 		g_print ("%c[%dm", 0x1B, 31);
 	if (g_strcmp0 (title, "reply") == 0)
 		g_print ("%c[%dm", 0x1B, 34);
 	g_print ("%s\t", title);
 
-	for (i=0; i< length; i++)
+	for (guint i = 0; i< length; i++) {
 		g_print ("%02x [%c]\t",
 			 data[i],
 			 g_ascii_isprint (data[i]) ? data[i] : '?');
-
+	}
 	g_print ("%c[%dm\n", 0x1B, 0);
 }
 
@@ -307,15 +292,14 @@ g_usb_test_button_pressed_cb (GObject      *source_object,
 			      gpointer      user_data)
 {
 	gboolean ret;
-	GError *error = NULL;
 	GUsbDeviceAsyncHelper *helper = (GUsbDeviceAsyncHelper *) user_data;
+	g_autoptr(GError) error = NULL;
 
 	ret = g_usb_device_interrupt_transfer_finish (G_USB_DEVICE (source_object),
 						      res, &error);
 
 	if (!ret) {
 		g_error ("%s", error->message);
-		g_error_free (error);
 		return;
 	}
 
@@ -329,13 +313,13 @@ g_usb_test_button_pressed_cb (GObject      *source_object,
 static void
 gusb_device_munki_func (void)
 {
-	GError *error = NULL;
-	GUsbContext *ctx;
-	GUsbDevice *device;
 	gboolean ret;
 	GCancellable *cancellable = NULL;
 	guint8 request[24];
 	GUsbDeviceAsyncHelper *helper;
+	g_autoptr(GError) error = NULL;
+	g_autoptr(GUsbContext) ctx = NULL;
+	g_autoptr(GUsbDevice) device = NULL;
 
 	ctx = g_usb_context_new (&error);
 	g_assert_no_error (error);
@@ -352,8 +336,7 @@ gusb_device_munki_func (void)
 	    error->domain == G_USB_DEVICE_ERROR &&
 	    error->code == G_USB_DEVICE_ERROR_NO_DEVICE) {
 		g_print ("No device detected!\n");
-		g_error_free (error);
-		goto out;
+		return;
 	}
 	g_assert_no_error (error);
 	g_assert (device != NULL);
@@ -450,21 +433,17 @@ gusb_device_munki_func (void)
 	ret = g_usb_device_close (device, &error);
 	g_assert_no_error (error);
 	g_assert (ret);
-
-	g_object_unref (device);
-out:
-	g_object_unref (ctx);
 }
 
 static void
 gusb_device_ch2_func (void)
 {
-	GError *error = NULL;
-	GUsbContext *ctx;
-	GUsbDevice *device;
 	gboolean ret;
-	gchar *tmp = NULL;
 	guint8 idx;
+	g_autofree gchar *tmp = NULL;
+	g_autoptr(GError) error = NULL;
+	g_autoptr(GUsbContext) ctx = NULL;
+	g_autoptr(GUsbDevice) device = NULL;
 
 	ctx = g_usb_context_new (&error);
 	g_assert_no_error (error);
@@ -481,8 +460,7 @@ gusb_device_ch2_func (void)
 	    error->domain == G_USB_DEVICE_ERROR &&
 	    error->code == G_USB_DEVICE_ERROR_NO_DEVICE) {
 		g_print ("No device detected!\n");
-		g_error_free (error);
-		goto out;
+		return;
 	}
 	g_assert_no_error (error);
 	g_assert (device != NULL);
@@ -503,16 +481,11 @@ gusb_device_ch2_func (void)
 	tmp = g_usb_device_get_string_descriptor (device, idx, &error);
 	g_assert_no_error (error);
 	g_assert_cmpstr (tmp, ==, "2.0.3");
-	g_free (tmp);
 
 	/* close */
 	ret = g_usb_device_close (device, &error);
 	g_assert_no_error (error);
 	g_assert (ret);
-
-	g_object_unref (device);
-out:
-	g_object_unref (ctx);
 }
 
 int
diff --git a/tools/gusb-main.c b/tools/gusb-main.c
index 55be333..8caad29 100644
--- a/tools/gusb-main.c
+++ b/tools/gusb-main.c
@@ -77,14 +77,9 @@ gusb_sort_command_name_cb (GUsbCmdItem **item1, GUsbCmdItem **item2)
 static void
 gusb_cmd_add (GPtrArray *array, const gchar *name, const gchar *description, GUsbCmdPrivateCb callback)
 {
-	gchar **names;
-	guint i;
-	GUsbCmdItem *item;
-
-	/* add each one */
-	names = g_strsplit (name, ",", -1);
-	for (i=0; names[i] != NULL; i++) {
-		item = g_slice_new0 (GUsbCmdItem);
+	g_auto(GStrv) names = g_strsplit (name, ",", -1);
+	for (guint i = 0; names[i] != NULL; i++) {
+		GUsbCmdItem *item = g_slice_new0 (GUsbCmdItem);
 		item->name = g_strdup (names[i]);
 		if (i == 0) {
 			item->description = g_strdup (description);
@@ -96,28 +91,24 @@ gusb_cmd_add (GPtrArray *array, const gchar *name, const gchar *description, GUs
 		item->callback = callback;
 		g_ptr_array_add (array, item);
 	}
-	g_strfreev (names);
 }
 
 static gchar *
 gusb_cmd_get_descriptions (GPtrArray *array)
 {
-	guint i;
-	guint j;
 	guint len;
 	guint max_len = 19;
-	GUsbCmdItem *item;
-	GString *string;
+	g_autoptr(GString) string = NULL;
 
 	/* print each command */
 	string = g_string_new ("");
-	for (i = 0; i < array->len; i++) {
-		item = g_ptr_array_index (array, i);
+	for (guint i = 0; i < array->len; i++) {
+		GUsbCmdItem *item = g_ptr_array_index (array, i);
 		g_string_append (string, "  ");
 		g_string_append (string, item->name);
 		g_string_append (string, " ");
 		len = strlen (item->name);
-		for (j = len; j < max_len+2; j++)
+		for (guint j = len; j < max_len+2; j++)
 			g_string_append_c (string, ' ');
 		g_string_append (string, item->description);
 		g_string_append_c (string, '\n');
@@ -127,33 +118,30 @@ gusb_cmd_get_descriptions (GPtrArray *array)
 	if (string->len > 0)
 		g_string_set_size (string, string->len - 1);
 
-	return g_string_free (string, FALSE);
+	return g_string_free (g_steal_pointer(&string), FALSE);
 }
 
 static void
 gusb_main_device_open (GUsbDevice *device)
 {
-	GError *error = NULL;
 	guint8 idx;
+	g_autoptr(GError) error = NULL;
 
 	/* open */
 	if (!g_usb_device_open (device, &error)) {
 		g_print ("failed to open: %s\n", error->message);
-		g_error_free (error);
 		return;
 	}
 
 	/* print info we can only get whilst open */
 	idx = g_usb_device_get_product_index (device);
 	if (idx != 0x00) {
-		gchar *product = g_usb_device_get_string_descriptor (device, idx, &error);
+		g_autofree gchar *product = g_usb_device_get_string_descriptor (device, idx, &error);
 		if (product == NULL) {
 			g_print ("failed to get string desc: %s\n", error->message);
-			g_error_free (error);
 			return;
 		}
 		g_print ("product: %s\n", product);
-		g_free (product);
 	}
 }
 
@@ -193,12 +181,10 @@ static gboolean
 moo_cb (GNode *node, gpointer data)
 {
 	GUsbDevice *device = G_USB_DEVICE (node->data);
-	GNode *n;
-	guint i;
 	const gchar *tmp;
-	gchar *product = NULL;
-	gchar *vendor = NULL;
-	GString *str = NULL;
+	g_autofree gchar *product = NULL;
+	g_autofree gchar *vendor = NULL;
+	g_autoptr(GString) str = NULL;
 
 	if (device == NULL) {
 		g_print ("Root Device\n");
@@ -207,7 +193,7 @@ moo_cb (GNode *node, gpointer data)
 
 	/* indent */
 	str = g_string_new ("");
-	for (n = node; n->data != NULL; n = n->parent)
+	for (GNode *n = node; n->data != NULL; n = n->parent)
 		g_string_append (str, " ");
 
 	/* add bus:address */
@@ -218,7 +204,7 @@ moo_cb (GNode *node, gpointer data)
 			        g_usb_device_get_pid (device));
 
 	/* pad */
-	for (i = str->len; i < 30; i++)
+	for (guint i = str->len; i < 30; i++)
 		g_string_append (str, " ");
 
 	/* We don't error check these as not all devices have these
@@ -258,24 +244,16 @@ moo_cb (GNode *node, gpointer data)
 
 	/* add bus:address */
 	g_string_append_printf (str, "%s - %s", vendor, product);
-	g_free (product);
-	g_free (vendor);
 
 	g_print ("%s\n", str->str);
-	g_string_free (str, TRUE);
-
 	return FALSE;
 }
 
 static gboolean
 gusb_cmd_show (GUsbCmdPrivate *priv, gchar **values, GError **error)
 {
-	GNode *n;
-	GNode *node;
-	guint i;
-	GUsbDevice *device;
-	GUsbDevice *parent;
-	GPtrArray *devices = NULL;
+	g_autoptr(GNode) node = NULL;
+	g_autoptr(GPtrArray) devices = NULL;
 
 	/* sort */
 	devices = g_usb_context_get_devices (priv->usb_ctx);
@@ -283,10 +261,10 @@ gusb_cmd_show (GUsbCmdPrivate *priv, gchar **values, GError **error)
 
 	/* make a tree of the devices */
 	node = g_node_new (NULL);
-	for (i = 0; i < devices->len; i++) {
-		device = g_ptr_array_index (devices, i);
-
-		parent = g_usb_device_get_parent (device);
+	for (guint i = 0; i < devices->len; i++) {
+		GNode *n;
+		GUsbDevice *device = g_ptr_array_index (devices, i);
+		GUsbDevice *parent = g_usb_device_get_parent (device);
 		if (parent == NULL) {
 			g_node_append_data (node, device);
 			continue;
@@ -302,24 +280,19 @@ gusb_cmd_show (GUsbCmdPrivate *priv, gchar **values, GError **error)
 
 	}
 
-	g_ptr_array_unref (devices);
 	g_node_traverse (node, G_PRE_ORDER, G_TRAVERSE_ALL, -1, moo_cb, priv);
-
 	return TRUE;
 }
 
 static gboolean
 gusb_cmd_watch (GUsbCmdPrivate *priv, gchar **values, GError **error)
 {
-	gboolean ret = TRUE;
-	GPtrArray *devices;
-	guint i;
-	GUsbDevice *device;
-	GMainLoop *loop;
+	g_autoptr(GMainLoop) loop = NULL;
+	g_autoptr(GPtrArray) devices = NULL;
 
 	devices = g_usb_context_get_devices (priv->usb_ctx);
-	for (i = 0; i < devices->len; i++) {
-		device = g_ptr_array_index (devices, i);
+	for (guint i = 0; i < devices->len; i++) {
+		GUsbDevice *device = g_ptr_array_index (devices, i);
 		g_print ("device %s already present %x:%x\n",
 			 g_usb_device_get_platform_id (device),
 			 g_usb_device_get_bus (device),
@@ -335,18 +308,15 @@ gusb_cmd_watch (GUsbCmdPrivate *priv, gchar **values, GError **error)
 			  G_CALLBACK (gusb_device_list_removed_cb),
 			  priv);
 	g_main_loop_run (loop);
-
-	g_main_loop_unref (loop);
-	g_ptr_array_unref (devices);
-	return ret;
+	return TRUE;
 }
 
 static gboolean
 gusb_cmd_replug (GUsbCmdPrivate *priv, gchar **values, GError **error)
 {
-	GUsbDevice *device;
-	GUsbDevice *device_new;
 	guint16 vid, pid;
+	g_autoptr(GUsbDevice) device = NULL;
+	g_autoptr(GUsbDevice) device_new = NULL;
 
 	/* check args */
 	if (g_strv_length (values) != 2) {
@@ -376,54 +346,53 @@ gusb_cmd_replug (GUsbCmdPrivate *priv, gchar **values, GError **error)
 						    device,
 						    5000,
 						    error);
-	if (device_new == NULL)
-		return FALSE;
-
-	g_object_unref (device);
-	return TRUE;
+	return device_new != NULL;
 }
 
 static gboolean
 gusb_cmd_run (GUsbCmdPrivate *priv, const gchar *command, gchar **values, GError **error)
 {
-	gboolean ret = FALSE;
-	guint i;
-	GUsbCmdItem *item;
-	GString *string;
+	g_autoptr(GString) string = g_string_new (NULL);
 
 	/* find command */
-	for (i = 0; i < priv->cmd_array->len; i++) {
-		item = g_ptr_array_index (priv->cmd_array, i);
+	for (guint i = 0; i < priv->cmd_array->len; i++) {
+		GUsbCmdItem *item = g_ptr_array_index (priv->cmd_array, i);
 		if (g_strcmp0 (item->name, command) == 0) {
-			ret = item->callback (priv, values, error);
-			goto out;
+			return item->callback (priv, values, error);
 		}
 	}
 
-	/* not found */
-	string = g_string_new ("");
 	/* TRANSLATORS: error message */
 	g_string_append_printf (string, "%s\n", "Command not found, valid commands are:");
-	for (i = 0; i < priv->cmd_array->len; i++) {
-		item = g_ptr_array_index (priv->cmd_array, i);
+	for (guint i = 0; i < priv->cmd_array->len; i++) {
+		GUsbCmdItem *item = g_ptr_array_index (priv->cmd_array, i);
 		g_string_append_printf (string, " * %s\n", item->name);
 	}
 	g_set_error_literal (error, 1, 0, string->str);
-	g_string_free (string, TRUE);
-out:
-	return ret;
+	return FALSE;
+}
+
+static void
+gusb_cmd_private_free(GUsbCmdPrivate *priv)
+{
+	if (priv->cmd_array != NULL)
+		g_ptr_array_unref (priv->cmd_array);
+	if (priv->usb_ctx != NULL)
+		g_object_unref (priv->usb_ctx);
+	g_option_context_free (priv->context);
+	g_slice_free (GUsbCmdPrivate, priv);
 }
 
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GUsbCmdPrivate, gusb_cmd_private_free)
+
 int
 main (int argc, char *argv[])
 {
-	gboolean ret;
 	gboolean verbose = FALSE;
-	gchar *cmd_descriptions = NULL;
-	gchar *options_help = NULL;
-	GError *error = NULL;
-	gint retval = 0;
-	GUsbCmdPrivate *priv;
+	g_autofree gchar *cmd_descriptions = NULL;
+	g_autofree gchar *options_help = NULL;
+	g_autoptr(GError) error = NULL;
+	g_autoptr(GUsbCmdPrivate) priv = NULL;
 
 	const GOptionEntry options[] = {
 		{ "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose,
@@ -435,14 +404,11 @@ main (int argc, char *argv[])
 
 	/* create helper object */
 	priv = g_slice_new0 (GUsbCmdPrivate);
-
 	priv->context = g_option_context_new ("GUSB Console Program");
 	g_option_context_add_main_entries (priv->context, options, NULL);
 	if (!g_option_context_parse (priv->context, &argc, &argv, &error)) {
 		g_printerr ("Failed to parse arguments: %s\n", error->message);
-		g_error_free (error);
-		retval = 2;
-		goto out;
+		return 2;
 	}
 
 	/* verbose? */
@@ -491,29 +457,15 @@ main (int argc, char *argv[])
 	if (argc < 2) {
 		options_help = g_option_context_get_help (priv->context, TRUE, NULL);
 		g_print ("%s", options_help);
-		goto out;
+		return 1;
 	}
 
 	/* run the specified command */
-	ret = gusb_cmd_run (priv, argv[1], (gchar**) &argv[2], &error);
-	if (!ret) {
+	if (!gusb_cmd_run (priv, argv[1], (gchar**) &argv[2], &error)) {
 		g_print ("%s\n", error->message);
-		g_error_free (error);
-		retval = 1;
-		goto out;
-	}
-out:
-	if (priv != NULL) {
-		if (priv->cmd_array != NULL)
-			g_ptr_array_unref (priv->cmd_array);
-		if (priv->usb_ctx != NULL)
-			g_object_unref (priv->usb_ctx);
-		g_option_context_free (priv->context);
-		g_slice_free (GUsbCmdPrivate, priv);
+		return 1;
 	}
 
-	/* free state */
-	g_free (options_help);
-	g_free (cmd_descriptions);
-	return retval;
+	/* success */
+	return 0;
 }