On Nov 26, 2015 1:23 PM, "Derek Foreman" <<a href="mailto:derekf@osg.samsung.com">derekf@osg.samsung.com</a>> wrote: > > This sets wl_display's version (for proxy version query purposes) > to 0. Any proxy created with unversioned API (this happens when > a client compiled with old headers links against new wayland) > will inherit this 0. > > This gives us a way for new libraries linked by old clients to > realize they can't know a proxy's version. > > wl_display's version being unqueryable (always returning 0) is > an acceptable side effect, since it's a special object you can't > bind specific versions of anyway. > > Signed-off-by: Derek Foreman <<a href="mailto:derekf@osg.samsung.com">derekf@osg.samsung.com</a>> Reviewed-by: Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> > --- > > This follows on Jason's proxy version patch that I rebased > and reposted a little while ago. > > src/wayland-client.c | 33 +++++++++++++++++++++++++++++++-- > 1 file changed, 31 insertions(+), 2 deletions(-) > > diff --git a/src/wayland-client.c b/src/wayland-client.c > index f2df0b9..5ba6edc 100644 > --- a/src/wayland-client.c > +++ b/src/wayland-client.c > @@ -928,7 +928,25 @@ wl_display_connect_to_fd(int fd) > display->proxy.queue = &display->default_queue; > display->proxy.flags = 0; > display->proxy.refcount = 1; > - display->proxy.version = 1; > + > + /* We set this version to 0 for backwards compatibility. > + * > + * If a client is using old versions of protocol headers, > + * it will use unversioned API to create proxies. Those > + * proxies will inherit this 0. > + * > + * A client could be passing these proxies into library > + * code newer than the headers that checks proxy > + * versions. When the proxy version is reported as 0 > + * the library will know that it can't reliably determine > + * the proxy version, and should do whatever fallback is > + * required. > + * > + * This trick forces wl_display to always report 0, but > + * since it's a special object that we can't bind > + * specific versions of anyway, this should be fine. > + */ > + display->proxy.version = 0; > > display->connection = wl_connection_create(display->fd); > if (display->connection == NULL) > @@ -1923,7 +1941,18 @@ wl_proxy_get_user_data(struct wl_proxy *proxy) > /** Get the protocol object version of a proxy object > * > * \param proxy The proxy object > - * \return The protocol object version of the proxy > + * \return The protocol object version of the proxy or 0 > + * > + * Gets the protocol object version of a proxy object, or 0 > + * if the proxy was created with unversioned API. > + * > + * A returned value of 0 means that no version information is > + * available, so the caller must make safe assumptions about > + * the object's real version. > + * > + * wl_display's version will always return 0. > + * > + * \note This should not normally be used by non-generated code. > * > * \memberof wl_proxy > */ > -- > 2.6.2 >