Add example-unix-fd-client.c

It should work like this:

 $ ./example-server
 On Mon Apr 26 19:06:28 2010, example-unix-fd-client with pid 27957 was here!
 On Mon Apr 26 19:06:30 2010, example-unix-fd-client with pid 27974 was here!

 $ ./example-unix-fd-client
 Wrote the following on server's stdout:
 On Mon Apr 26 19:06:28 2010, example-unix-fd-client with pid 27957 was here!
 $ ./example-unix-fd-client
 Wrote the following on server's stdout:
 On Mon Apr 26 19:06:30 2010, example-unix-fd-client with pid 27974 was here!
 $

7 files changed, 256 insertions, 47 deletions

diff --git a/docs/reference/gdbus/gdbus-standalone-sections.txt b/docs/reference/gdbus/gdbus-standalone-sections.txt
index a2d0819..e91f948 100644
--- a/docs/reference/gdbus/gdbus-standalone-sections.txt
+++ b/docs/reference/gdbus/gdbus-standalone-sections.txt
@@ -62,6 +62,7 @@ g_dbus_message_get_arg0
 g_dbus_message_to_blob
 g_dbus_message_bytes_needed
 g_dbus_message_new_from_blob
+g_dbus_message_to_gerror
 <SUBSECTION Standard>
 G_DBUS_MESSAGE
 G_IS_DBUS_MESSAGE
diff --git a/gdbus/Makefile.am b/gdbus/Makefile.am
index 21e6155..3122307 100644
--- a/gdbus/Makefile.am
+++ b/gdbus/Makefile.am
@@ -142,6 +142,7 @@ noinst_PROGRAMS += example-own-name
 noinst_PROGRAMS += example-watch-name
 noinst_PROGRAMS += example-watch-proxy
 noinst_PROGRAMS += example-server
+noinst_PROGRAMS += example-unix-fd-client
 noinst_PROGRAMS += example-subtree
 
 example_watch_name_SOURCES = example-watch-name.c
@@ -160,6 +161,10 @@ example_server_SOURCES = example-server.c
 example_server_CFLAGS  = $(GLIB2_CFLAGS) $(GOBJECT2_CFLAGS) $(GIO2_CFLAGS) $(GIO_UNIX2_CFLAGS)
 example_server_LDADD   = libgdbus-standalone.la $(GLIB2_LIBS) $(GOBJECT2_LIBS) $(GIO2_LIBS) $(GIO_UNIX2_LIBS)
 
+example_unix_fd_client_SOURCES = example-unix-fd-client.c
+example_unix_fd_client_CFLAGS  = $(GLIB2_CFLAGS) $(GOBJECT2_CFLAGS) $(GIO2_CFLAGS) $(GIO_UNIX2_CFLAGS)
+example_unix_fd_client_LDADD   = libgdbus-standalone.la $(GLIB2_LIBS) $(GOBJECT2_LIBS) $(GIO2_LIBS) $(GIO_UNIX2_LIBS)
+
 example_subtree_SOURCES = example-subtree.c
 example_subtree_CFLAGS  = $(GLIB2_CFLAGS) $(GOBJECT2_CFLAGS) $(GIO2_CFLAGS) $(GIO_UNIX2_CFLAGS)
 example_subtree_LDADD   = libgdbus-standalone.la $(GLIB2_LIBS) $(GOBJECT2_LIBS) $(GIO2_LIBS) $(GIO_UNIX2_LIBS)
diff --git a/gdbus/example-server.c b/gdbus/example-server.c
index 7b4a420..2601c09 100644
--- a/gdbus/example-server.c
+++ b/gdbus/example-server.c
@@ -2,6 +2,11 @@
 #include <gdbus/gdbus.h>
 #include <stdlib.h>
 
+#ifdef G_OS_UNIX
+/* For STDOUT_FILENO */
+#include <unistd.h>
+#endif
+
 /* ---------------------------------------------------------------------------------------------------- */
 
 static GDBusNodeInfo *introspection_data = NULL;
@@ -17,6 +22,7 @@ static const gchar introspection_xml[] =
   "    <method name='EmitSignal'>"
   "      <arg type='d' name='speed_in_mph' direction='in'/>"
   "    </method>"
+  "    <method name='GimmeStdout'/>"
   "    <signal name='VelocityChanged'>"
   "      <arg type='d' name='speed_in_mph'/>"
   "      <arg type='s' name='speed_as_string'/>"
@@ -102,6 +108,46 @@ handle_method_call (GDBusConnection       *connection,
 
       g_dbus_method_invocation_return_value (invocation, NULL);
     }
+  else if (g_strcmp0 (method_name, "GimmeStdout") == 0)
+    {
+#ifdef G_OS_UNIX
+      if (g_dbus_connection_get_capabilities (connection) & G_DBUS_CONNECTION_CAPABILITY_FLAGS_UNIX_FD_PASSING)
+        {
+          GDBusMessage *reply;
+          GUnixFDList *fd_list;
+          GError *error;
+
+          fd_list = g_unix_fd_list_new ();
+          error = NULL;
+          g_unix_fd_list_append (fd_list, STDOUT_FILENO, &error);
+          g_assert_no_error (error);
+
+          reply = g_dbus_message_new_method_reply (g_dbus_method_invocation_get_message (invocation));
+          g_dbus_message_set_unix_fd_list (reply, fd_list);
+
+          error = NULL;
+          g_dbus_connection_send_message (connection,
+                                          reply,
+                                          NULL, /* out_serial */
+                                          &error);
+          g_assert_no_error (error);
+
+          g_object_unref (invocation);
+          g_object_unref (fd_list);
+          g_object_unref (reply);
+        }
+      else
+        {
+          g_dbus_method_invocation_return_dbus_error (invocation,
+                                                      "org.gtk.GDBus.Failed",
+                                                      "Your message bus daemon does not support file descriptor passing (need D-Bus >= 1.3.0)");
+        }
+#else
+      g_dbus_method_invocation_return_dbus_error (invocation,
+                                                  "org.gtk.GDBus.NotOnUnix",
+                                                  "Your OS does not support file descriptor passing");
+#endif
+    }
 }
 
 static gchar *_global_title = NULL;
diff --git a/gdbus/example-unix-fd-client.c b/gdbus/example-unix-fd-client.c
new file mode 100644
index 0000000..6729913
--- /dev/null
+++ b/gdbus/example-unix-fd-client.c
@@ -0,0 +1,132 @@
+
+#include <string.h>
+#include <stdlib.h>
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <time.h>
+
+#include <gdbus/gdbus.h>
+
+/* see example-server.c for the server implementation */
+static gint
+get_server_stdout (GDBusConnection  *connection,
+                   const gchar      *name_owner,
+                   GError          **error)
+{
+  GDBusMessage *method_call_message;
+  GDBusMessage *method_reply_message;
+  GUnixFDList *fd_list;
+  gint fd;
+
+  fd = -1;
+  method_call_message = NULL;
+  method_reply_message = NULL;
+
+  method_call_message = g_dbus_message_new_method_call (name_owner,
+                                                        "/org/gtk/GDBus/TestObject",
+                                                        "org.gtk.GDBus.TestInterface",
+                                                        "GimmeStdout");
+  method_reply_message = g_dbus_connection_send_message_with_reply_sync (connection,
+                                                                         method_call_message,
+                                                                         -1,
+                                                                         NULL, /* out_serial */
+                                                                         NULL, /* cancellable */
+                                                                         error);
+  if (method_reply_message == NULL)
+      goto out;
+
+  if (g_dbus_message_get_type (method_reply_message) == G_DBUS_MESSAGE_TYPE_ERROR)
+    {
+      g_dbus_message_to_gerror (method_reply_message, error);
+      goto out;
+    }
+
+  fd_list = g_dbus_message_get_unix_fd_list (method_reply_message);
+  fd = g_unix_fd_list_get (fd_list, 0, error);
+
+ out:
+  g_object_unref (method_call_message);
+  g_object_unref (method_reply_message);
+
+  return fd;
+}
+
+static void
+on_name_appeared (GDBusConnection *connection,
+                  const gchar     *name,
+                  const gchar     *name_owner,
+                  gpointer         user_data)
+{
+  gint fd;
+  GError *error;
+
+  error = NULL;
+  fd = get_server_stdout (connection, name_owner, &error);
+  if (fd == -1)
+    {
+      g_printerr ("Error invoking GimmeStdout(): %s\n",
+                  error->message);
+      g_error_free (error);
+      exit (1);
+    }
+  else
+    {
+      gchar now_buf[256];
+      time_t now;
+      gssize len;
+      gchar *str;
+
+      now = time (NULL);
+      strftime (now_buf,
+                sizeof now_buf,
+                "%c",
+                localtime (&now));
+
+      str = g_strdup_printf ("On %s, example-unix-fd-client with pid %d was here!\n",
+                             now_buf,
+                             (gint) getpid ());
+      len = strlen (str);
+      g_assert (write (fd, str, len) == len);
+      close (fd);
+
+      g_print ("Wrote the following on server's stdout:\n%s", str);
+
+      g_free (str);
+      exit (0);
+    }
+}
+
+static void
+on_name_vanished (GDBusConnection *connection,
+                  const gchar     *name,
+                  gpointer         user_data)
+{
+  g_printerr ("Failed to get name owner for %s\n"
+              "Is ./example-server running?\n",
+              name);
+  exit (1);
+}
+
+int
+main (int argc, char *argv[])
+{
+  guint watcher_id;
+  GMainLoop *loop;
+
+  g_type_init ();
+
+  watcher_id = g_bus_watch_name (G_BUS_TYPE_SESSION,
+                                 "org.gtk.GDBus.TestServer",
+                                 on_name_appeared,
+                                 on_name_vanished,
+                                 NULL,
+                                 NULL);
+
+  loop = g_main_loop_new (NULL, FALSE);
+  g_main_loop_run (loop);
+
+  g_bus_unwatch_name (watcher_id);
+  return 0;
+}
diff --git a/gdbus/gdbusconnection.c b/gdbus/gdbusconnection.c
index fb5e9d6..a2dd318 100644
--- a/gdbus/gdbusconnection.c
+++ b/gdbus/gdbusconnection.c
@@ -3883,7 +3883,6 @@ static GVariant *
 decode_method_reply (GDBusMessage *reply, GError **error)
 {
   GVariant *result;
-  const gchar *error_name;
 
   result = NULL;
   switch (g_dbus_message_get_type (reply))
@@ -3901,52 +3900,7 @@ decode_method_reply (GDBusMessage *reply, GError **error)
         }
       break;
     case G_DBUS_MESSAGE_TYPE_ERROR:
-      error_name = g_dbus_message_get_error_name (reply);
-      if (error_name != NULL)
-        {
-          GVariant *body;
-
-          body = g_dbus_message_get_body (reply);
-
-          if (body != NULL && g_variant_is_of_type (body, G_VARIANT_TYPE ("(s)")))
-            {
-              const gchar *error_message;
-              g_variant_get (body, "(s)", &error_message);
-              g_dbus_error_set_dbus_error (error,
-                                           error_name,
-                                           error_message,
-                                           NULL);
-            }
-          else
-            {
-              /* these two situations are valid, yet pretty rare */
-              if (body != NULL)
-                {
-                  g_dbus_error_set_dbus_error (error,
-                                               error_name,
-                                               "",
-                                               _("Error return with body of type `%s'"),
-                                               g_variant_get_type_string (body));
-                }
-              else
-                {
-                  g_dbus_error_set_dbus_error (error,
-                                               error_name,
-                                               "",
-                                               _("Error return with empty body"));
-                }
-            }
-        }
-      else
-        {
-          /* TOOD: this shouldn't happen - should check this at message serialization
-           * time and disconnect the peer
-           */
-          g_set_error (error,
-                       G_IO_ERROR,
-                       G_IO_ERROR_FAILED,
-                       "Error return without error-name header!");
-        }
+      g_dbus_message_to_gerror (reply, error);
       break;
 
     default:
diff --git a/gdbus/gdbusmessage.c b/gdbus/gdbusmessage.c
index 2bf5f84..d01c801 100644
--- a/gdbus/gdbusmessage.c
+++ b/gdbus/gdbusmessage.c
@@ -1670,3 +1670,71 @@ g_dbus_message_set_num_unix_fds (GDBusMessage  *message,
 }
 
 /* ---------------------------------------------------------------------------------------------------- */
+
+gboolean
+g_dbus_message_to_gerror (GDBusMessage   *message,
+                          GError        **error)
+{
+  gboolean ret;
+  const gchar *error_name;
+
+  g_return_val_if_fail (G_IS_DBUS_MESSAGE (message), FALSE);
+
+  ret = FALSE;
+  if (message->priv->type != G_DBUS_MESSAGE_TYPE_ERROR)
+    goto out;
+
+  error_name = g_dbus_message_get_error_name (message);
+  if (error_name != NULL)
+    {
+      GVariant *body;
+
+      body = g_dbus_message_get_body (message);
+
+      if (body != NULL && g_variant_is_of_type (body, G_VARIANT_TYPE ("(s)")))
+        {
+          const gchar *error_message;
+          g_variant_get (body, "(s)", &error_message);
+          g_dbus_error_set_dbus_error (error,
+                                       error_name,
+                                       error_message,
+                                       NULL);
+        }
+      else
+        {
+          /* these two situations are valid, yet pretty rare */
+          if (body != NULL)
+            {
+              g_dbus_error_set_dbus_error (error,
+                                           error_name,
+                                           "",
+                                           _("Error return with body of type `%s'"),
+                                           g_variant_get_type_string (body));
+            }
+          else
+            {
+              g_dbus_error_set_dbus_error (error,
+                                           error_name,
+                                           "",
+                                           _("Error return with empty body"));
+            }
+        }
+    }
+  else
+    {
+      /* TOOD: this shouldn't happen - should check this at message serialization
+       * time and disconnect the peer.
+       */
+      g_set_error (error,
+                   G_IO_ERROR,
+                   G_IO_ERROR_FAILED,
+                   "Error return without error-name header!");
+    }
+
+  ret = TRUE;
+
+ out:
+  return ret;
+}
+
+/* ---------------------------------------------------------------------------------------------------- */
diff --git a/gdbus/gdbusmessage.h b/gdbus/gdbusmessage.h
index 499d158..2ca6618 100644
--- a/gdbus/gdbusmessage.h
+++ b/gdbus/gdbusmessage.h
@@ -153,6 +153,9 @@ guchar                   *g_dbus_message_to_blob            (GDBusMessage
                                                              gsize                    *out_size,
                                                              GError                  **error);
 
+gboolean                  g_dbus_message_to_gerror          (GDBusMessage             *message,
+                                                             GError                  **error);
+
 G_END_DECLS
 
 #endif /* __G_DBUS_MESSAGE_H__ */