<div dir="ltr">This sounds like a good idea to me. </div><div class="gmail_extra"> <div class="gmail_quote">On Wed, Jan 23, 2013 at 8:38 PM, Peter Hutterer <<a href="mailto:peter.hutterer@who-t.net" target="_blank">peter.hutterer@who-t.net</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">XIQueryVersion sends the client-supported version to the server. The server then uses that version to adjust the behaviour of XI2 for this client. Current examples include: * XIQueryPointer will not set the button mask for touch events if the client is XI 2.2-aware * RawEvents are sent to XI 2.1 clients if a grab is active * XIAllowEvents will accept different values from XI 2.2 clients This behaviour is an issue for libraries supporting XI2. A library that calls XIQueryVersion before the client will lock in behaviour that the client may not request. A library that calls XIQueryVersion after the client may trigger BadValue errors if the libraries requested version differs from the client's requested version. This request adds a side-effect free version of XIQueryVersion. It returns the server version and the already-requested client version (if any). A library may use this request to query the server for the XI2 version withouth locking in any behaviour for the client. Signed-off-by: Peter Hutterer <<a href="mailto:peter.hutterer@who-t.net">peter.hutterer@who-t.net</a>> --- I was tempted to call this XIQueryServerVersion but IMO that is too close to XIQueryVersion. Returning the client version is to determine what the client actually expects in behavior. Not 100% sure if needed, but if it is needed this opens another question: do we need a XIQueryVersionCalled event? If the library calls XIGetSupportedVersion before the client calls XIQueryVersion, it won't have the information. Unless it keeps calling it until it gets a number back, which doesn't seem useful either. XI2proto.h | 30 +++++++++++++++++++++++++++++- specs/XI2proto.txt | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/XI2proto.h b/XI2proto.h index 4cdaa0d..e99c9d6 100644 --- a/XI2proto.h +++ b/XI2proto.h @@ -94,9 +94,10 @@ #define X_XIGetProperty 59 #define X_XIGetSelectedEvents 60 #define X_XIBarrierReleasePointer 61 +#define X_XIGetSupportedVersion 62 /** Number of XI requests */ -#define XI2REQUESTS (X_XIBarrierReleasePointer - X_XIQueryPointer + 1) +#define XI2REQUESTS (X_XIGetSupportedVersion - X_XIQueryPointer + 1) /** Number of XI2 events */ #define XI2EVENTS (XI_LASTEVENT + 1) @@ -833,6 +834,33 @@ typedef struct { } xXIBarrierReleasePointerReq; #define sz_xXIBarrierReleasePointerReq 8 +/** + * Retrieve the server-supported X Input extension version. + */ + +typedef struct { + uint8_t reqType; /**< Input extension major code */ + uint8_t ReqType; /**< Always ::X_XIGetSupportedVersion */ + uint16_t length; /**< Length in 4 byte units */ +} xXIGetSupportedVersionReq; +#define sz_xXIGetSupportedVersionReq 4 + +typedef struct { + uint8_t repType; /**< ::X_Reply */ + uint8_t RepType; /**< Always ::X_XIGetSupportedVersion */ + uint16_t sequenceNumber; + uint32_t length; + uint16_t server_major_version; + uint16_t server_minor_version; + uint16_t client_major_version; + uint16_t client_minor_version; + uint32_t pad1 + uint32_t pad3; + uint32_t pad4; + uint32_t pad5; +} xXIGetSupportedVersionReply; +#define sz_xXIGetSupportedVersionReply 32 + /************************************************************************************* * * * EVENTS * diff --git a/specs/XI2proto.txt b/specs/XI2proto.txt index d30fcca..b5d9afd 100644 --- a/specs/XI2proto.txt +++ b/specs/XI2proto.txt @@ -62,6 +62,7 @@ Changes in version 2.3 ---------------------- - Pointer barrier events added +- XIGetSupportedVersion request added // ❧❧❧❧❧❧❧❧❧❧❧ @@ -2035,6 +2036,39 @@ assigned and the client must re-issue the XIBarrierReleasePointer request. If the device is not a master pointer device, a BadDevice error results. If the barrier does not name a valid barrier, a BadValue error results. +XIGetSupportedVersion +^^^^^^^^^^^^^^ + ┌─── + XIGetSupportedVersion + ▶ + server_major_version: CARD16 + server_minor_version: CARD16 + client_major_version: CARD16 + client_minor_version: CARD16 + └─── + +This request queries the server for its supported XI2 version, and the +version this client has already registered for. It is side-effect free. + + server_major_version + Major XI2 version supported by the server. + server_minor_version + Minor XI2 version supported by the server. + client_major_version + Major XI2 version this client has registered for. + client_minor_version + Minor XI2 version this client has registered for. + +XIGetSupportedVersion returns the current supported server major/minor +version. It does not register this client for XI2 support and clients must +call XIQueryVersion with the version they support before issuing other XI2 +requests. + +XIGetSupportedVersion returns the major/minor version requested by this +client in a previous XIQueryVersion request. If the client has not +previously called XIQueryVersion, client_major_version and +client_minor_version is 0. + [[events]] Events -- 1.8.1 </blockquote></div> -- Jasper </div>