[PATCH inputproto 1/3] Unbreak protocol ABI for XIAllowEvents.

[Chase Douglas]

On 01/27/2012 06:50 AM, Peter Hutterer wrote:
> XIAllowEvents was extended with touchid and grab_window in
> 2ea2f99f4fe1dcd3b8e539ca41c482fc40a0533d. This extended the size of the
> request from 12 to 20 but also broke the ABI. Older server match the request
> size exactly, so compiling libXi 1.5 against inputproto 2.2 and then running
> it against a pre-XI 2.2 server causes a BadLength for any XIAllowEvent
> request.
> 
> Change the new fields from actual fields to simple comments and let the
> library/server deal with the extra data.
> 
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
>  XI2proto.h |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/XI2proto.h b/XI2proto.h
> index 93d7e32..9039fe7 100644
> --- a/XI2proto.h
> +++ b/XI2proto.h
> @@ -647,10 +647,10 @@ typedef struct {
>      uint16_t    deviceid;
>      uint8_t     mode;
>      uint8_t     pad;
> -    uint32_t    touchid;                /**< Since XI 2.2 */
> -    Window      grab_window;            /**< Since XI 2.2 */
> +    /* uint32_t    touchid;            Since XI 2.2 */
> +    /* Window      grab_window;        Since XI 2.2 */
>  } xXIAllowEventsReq;
> -#define sz_xXIAllowEventsReq                   20 /**< Was 12 before XI 2.2 */
> +#define sz_xXIAllowEventsReq                   12 /**< 20 in XI 2.2 */
>  
>  
>  /**

If we're going to break the abi between all three of inputproto, libxi,
and xserver, I'd like to ask if we should just skip all this
hoop-jumping and create new protocol requests for the XI 2.2 (and
hopefully XI 2.3) versions of AllowEvents. This is all getting very
hairy and error-prone. What are we really gaining by reusing a request
number?

-- Chase