libnm-core: add _nm_dbus_signal_connect()

Add _nm_dbus_signal_connect(), for connecting to D-Bus signals on a
GDBusProxy, with typechecking and pre-parsing of the parameters
variant.

1 files changed, 176 insertions, 0 deletions

diff --git a/libnm-core/nm-dbus-utils.c b/libnm-core/nm-dbus-utils.c
new file mode 100644
index 0000000000..aa1fdd9387
--- /dev/null
+++ b/libnm-core/nm-dbus-utils.c
@@ -0,0 +1,176 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
+/*
+ * 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 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.
+ *
+ * Copyright 2015 Red Hat, Inc.
+ */
+
+#include "config.h"
+
+#include <string.h>
+#include <gio/gio.h>
+
+#include "nm-core-internal.h"
+
+typedef struct {
+	char *signal_name;
+	const GVariantType *signature;
+} NMDBusSignalData;
+
+static void
+dbus_signal_data_free (gpointer data, GClosure *closure)
+{
+	NMDBusSignalData *sd = data;
+
+	g_free (sd->signal_name);
+	g_slice_free (NMDBusSignalData, sd);
+}
+
+static void
+dbus_signal_meta_marshal (GClosure     *closure,
+                          GValue       *return_value,
+                          guint         n_param_values,
+                          const GValue *param_values,
+                          gpointer      invocation_hint,
+                          gpointer      marshal_data)
+{
+	NMDBusSignalData *sd = marshal_data;
+	const char *signal_name;
+	GVariant *parameters, *param;
+	GValue *closure_params;
+	gsize n_params, i;
+
+	g_return_if_fail (n_param_values == 4);
+
+	signal_name = g_value_get_string (&param_values[2]);
+	parameters = g_value_get_variant (&param_values[3]);
+
+	if (strcmp (signal_name, sd->signal_name) != 0)
+		return;
+
+	if (sd->signature) {
+		if (!g_variant_is_of_type (parameters, sd->signature)) {
+			g_warning ("%p: got signal '%s' but parameters were of type '%s', not '%s'",
+			           g_value_get_object (&param_values[0]),
+			           signal_name, g_variant_get_type_string (parameters),
+			           g_variant_type_peek_string (sd->signature));
+			return;
+		}
+
+		n_params = g_variant_n_children (parameters) + 1;
+	} else
+		n_params = 1;
+
+	closure_params = g_new0 (GValue, n_params);
+	g_value_init (&closure_params[0], G_TYPE_OBJECT);
+	g_value_copy (&param_values[0], &closure_params[0]);
+
+	for (i = 1; i < n_params; i++) {
+		param = g_variant_get_child_value (parameters, i - 1);
+		if (   g_variant_is_of_type (param, G_VARIANT_TYPE ("ay"))
+		    || g_variant_is_of_type (param, G_VARIANT_TYPE ("aay"))) {
+			/* g_dbus_gvariant_to_gvalue() thinks 'ay' means "non-UTF-8 NUL-terminated string" */
+			g_value_init (&closure_params[i], G_TYPE_VARIANT);
+			g_value_set_variant (&closure_params[i], param);
+		} else
+			g_dbus_gvariant_to_gvalue (param, &closure_params[i]);
+		g_variant_unref (param);
+	}
+
+	g_cclosure_marshal_generic (closure,
+	                            NULL,
+	                            n_params,
+	                            closure_params,
+	                            invocation_hint,
+	                            NULL);
+
+	for (i = 0; i < n_params; i++)
+		g_value_unset (&closure_params[i]);
+	g_free (closure_params);
+}
+
+/**
+ * _nm_dbus_signal_connect_data:
+ * @proxy: a #GDBusProxy
+ * @signal_name: the D-Bus signal to connect to
+ * @signature: (allow-none): the signal's type signature (must be a tuple)
+ * @c_handler: the signal handler function
+ * @data: (allow-none): data to pass to @c_handler
+ * @destroy_data: (allow-none): closure destroy notify for @data
+ * @connect_flags: connection flags
+ *
+ * Connects to the D-Bus signal @signal_name on @proxy. @c_handler must be a
+ * void function whose first argument is a #GDBusProxy, followed by arguments
+ * for each element of @signature, ending with a #gpointer argument for @data.
+ *
+ * The argument types in @c_handler correspond to the types output by
+ * g_dbus_gvariant_to_gvalue(), except for 'ay' and 'aay'. In particular:
+ * - both 16-bit and 32-bit integers are passed as #gint/#guint
+ * - 'as' values are passed as #GStrv (char **)
+ * - all other array, tuple, and dict types are passed as #GVariant
+ *
+ * If @signature is %NULL, then the signal's parameters will be ignored, and
+ * @c_handler should take only the #GDBusProxy and #gpointer arguments.
+ *
+ * Returns: the signal handler ID, which can be used with
+ *   g_signal_handler_remove(). Beware that because of the way the signal is
+ *   connected, you will not be able to remove it with
+ *   g_signal_handlers_disconnect_by_func(), although
+ *   g_signal_handlers_disconnect_by_data() will work correctly.
+ */
+gulong
+_nm_dbus_signal_connect_data (GDBusProxy *proxy,
+                              const char *signal_name,
+                              const GVariantType *signature,
+                              GCallback c_handler,
+                              gpointer data,
+                              GClosureNotify destroy_data,
+                              GConnectFlags connect_flags)
+{
+	NMDBusSignalData *sd;
+	GClosure *closure;
+	gboolean swapped = !!(connect_flags & G_CONNECT_SWAPPED);
+	gboolean after = !!(connect_flags & G_CONNECT_AFTER);
+
+	g_return_val_if_fail (G_IS_DBUS_PROXY (proxy), 0);
+	g_return_val_if_fail (signal_name != NULL, 0);
+	g_return_val_if_fail (signature == NULL || g_variant_type_is_tuple (signature), 0);
+	g_return_val_if_fail (c_handler != NULL, 0);
+
+	sd = g_slice_new (NMDBusSignalData);
+	sd->signal_name = g_strdup (signal_name);
+	sd->signature = signature;
+
+	closure = (swapped ? g_cclosure_new_swap : g_cclosure_new) (c_handler, data, destroy_data);
+	g_closure_set_marshal (closure, g_cclosure_marshal_generic);
+	g_closure_set_meta_marshal (closure, sd, dbus_signal_meta_marshal);
+	g_closure_add_finalize_notifier (closure, sd, dbus_signal_data_free);
+
+	return g_signal_connect_closure (proxy, "g-signal", closure, after);
+}
+
+/**
+ * _nm_dbus_signal_connect:
+ * @proxy: a #GDBusProxy
+ * @signal_name: the D-Bus signal to connect to
+ * @signature: the signal's type signature (must be a tuple)
+ * @c_handler: the signal handler function
+ * @data: (allow-none): data to pass to @c_handler
+ *
+ * Simplified version of _nm_dbus_signal_connect_data() with fewer arguments.
+ *
+ * Returns: the signal handler ID, as with _nm_signal_connect_data().
+ */