[glib] GDBusMessage: Don't reset serial number when copying

[David Zeuthen <davidz src gnome org>]

commit 7c6606854400ba2a4d0c5b5a0eb96ba90845f82e
Author: David Zeuthen <davidz redhat com>
Date:   Thu Sep 9 15:15:13 2010 -0400

    GDBusMessage: Don't reset serial number when copying
    
    Ryan pointed out that it's safe to do this because we have the
    G_DBUS_SEND_MESSAGE_FLAGS_PRESERVE_SERIAL flag and that it simplifies
    how filter functions work.
    
    Signed-off-by: David Zeuthen <davidz redhat com>

 gio/gdbusconnection.h     |   12 ++++++------
 gio/gdbusmessage.c        |    3 ++-
 gio/gdbusprivate.c        |    6 ------
 gio/tests/gdbus-message.c |    2 +-
 4 files changed, 9 insertions(+), 14 deletions(-)
---
diff --git a/gio/gdbusconnection.h b/gio/gdbusconnection.h
index 4e3a80a..eb3e0f3 100644
--- a/gio/gdbusconnection.h
+++ b/gio/gdbusconnection.h
@@ -528,12 +528,12 @@ void             g_dbus_connection_signal_unsubscribe         (GDBusConnection
  *   return copy;
  * }
  * ]|
- * If the returned #GDBusMessage is different from @message and the
- * serial number is unset (e.g. zero), then @message's serial number
- * will be used on the returned message (so in this case the returned
- * message must be unlocked). Additionally, if the returned message
- * cannot be sent on @connection, then a warning is logged to
- * <emphasis>standard error</emphasis>.
+ * If the returned #GDBusMessage is different from @message and cannot
+ * be sent on @connection (it could use features, such as file
+ * descriptors, not compatible with @connection), then a warning is
+ * logged to <emphasis>standard error</emphasis>. Applications can
+ * check this ahead of time using g_dbus_message_to_blob() passing a
+ * #GDBusCapabilityFlags value obtained from @connection.
  *
  * Returns: (transfer full) (allow-none): A #GDBusMessage that will be freed with
  * g_object_unref() or %NULL to drop the message. Passive filter
diff --git a/gio/gdbusmessage.c b/gio/gdbusmessage.c
index c618105..0aca1e0 100644
--- a/gio/gdbusmessage.c
+++ b/gio/gdbusmessage.c
@@ -3190,7 +3190,7 @@ g_dbus_message_lock (GDBusMessage *message)
  *
  * Copies @message. The copy is a deep copy and the returned
  * #GDBusMessage is completely identical except that it is guaranteed
- * to not be locked and the serial will be set to 0.
+ * to not be locked.
  *
  * This operation can fail if e.g. @message contains file descriptors
  * and the per-process or system-wide open files limit is reached.
@@ -3217,6 +3217,7 @@ g_dbus_message_copy (GDBusMessage  *message,
   ret->flags                  = message->flags;
   ret->byte_order             = message->byte_order;
   ret->major_protocol_version = message->major_protocol_version;
+  ret->serial                 = message->serial;
 
 #ifdef G_OS_UNIX
   if (message->fd_list != NULL)
diff --git a/gio/gdbusprivate.c b/gio/gdbusprivate.c
index a9c4ce5..ca2680b 100644
--- a/gio/gdbusprivate.c
+++ b/gio/gdbusprivate.c
@@ -1244,14 +1244,12 @@ maybe_write_next_message (GDBusWorker *worker)
    */
   if (data != NULL)
     {
-      guint32 old_serial;
       GDBusMessage *old_message;
       guchar *new_blob;
       gsize new_blob_size;
       GError *error;
 
       old_message = data->message;
-      old_serial = g_dbus_message_get_serial (old_message);
       data->message = _g_dbus_worker_emit_message_about_to_be_sent (worker, data->message);
       if (data->message == old_message)
         {
@@ -1269,10 +1267,6 @@ maybe_write_next_message (GDBusWorker *worker)
       else
         {
           /* filters altered the message -> reencode */
-
-          if (g_dbus_message_get_serial (data->message) == 0)
-            g_dbus_message_set_serial (data->message, old_serial);
-
           error = NULL;
           new_blob = g_dbus_message_to_blob (data->message,
                                              &new_blob_size,
diff --git a/gio/tests/gdbus-message.c b/gio/tests/gdbus-message.c
index 981a951..b3be200 100644
--- a/gio/tests/gdbus-message.c
+++ b/gio/tests/gdbus-message.c
@@ -108,7 +108,7 @@ message_copy (void)
   g_assert_cmpint (G_OBJECT (m)->ref_count, ==, 1);
   g_assert_cmpint (G_OBJECT (copy)->ref_count, ==, 1);
 
-  g_assert_cmpint (g_dbus_message_get_serial (copy), ==, 0);
+  g_assert_cmpint (g_dbus_message_get_serial (copy), ==, g_dbus_message_get_serial (m));
   g_assert_cmpint (g_dbus_message_get_byte_order (copy), ==, g_dbus_message_get_byte_order (m));
   g_assert_cmpint (g_dbus_message_get_flags (copy), ==, g_dbus_message_get_flags (m));
   g_assert_cmpint (g_dbus_message_get_message_type (copy), ==, g_dbus_message_get_message_type (m));