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Xi: Work around broken libxcb that doesn't ignore unknown device classes 

libxcb 14.1 and older are not forwards-compatible with new device
classes as it does not properly ignore unknown device classes. Since
breaking libxcb would break quite a lot of applications, we instead
report Gesture device class only if the client advertised support for XI
2.4.

Clients may still not work in cases when a client advertises XI 2.4
support and then a completely separate module within the client uses
broken libxcb to call XIQueryDevice.

Signed-off-by: Povilas Kanapickas <povilas@radix.lt>
This commit is contained in:
Povilas Kanapickas 2021-05-30 13:26:48 +03:00
parent 7e692633fb
commit eb6f8daca5
1 changed files with 20 additions and 1 deletions
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21
Xi/xiquerydevice.c
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@ -43,6 +43,9 @@
#include "xace.h"
#include "inpututils.h"
#include "exglobals.h"
#include "privates.h"
#include "xiquerydevice.h"
static Bool ShouldSkipDevice(ClientPtr client, int deviceid, DeviceIntPtr d);
@ -467,6 +470,22 @@ SwapTouchInfo(DeviceIntPtr dev, xXITouchInfo * touch)
swaps(&touch->sourceid);
}
static Bool ShouldListGestureInfo(ClientPtr client)
{
/* libxcb 14.1 and older are not forwards-compatible with new device classes as it does not
* properly ignore unknown device classes. Since breaking libxcb would break quite a lot of
* applications, we instead report Gesture device class only if the client advertised support
* for XI 2.4. Clients may still not work in cases when a client advertises XI 2.4 support
* and then a completely separate module within the client uses broken libxcb to call
* XIQueryDevice.
*/
XIClientPtr pXIClient = dixLookupPrivate(&client->devPrivates, XIClientPrivateKey);
if (pXIClient->major_version) {
return version_compare(pXIClient->major_version, pXIClient->minor_version, 2, 4) >= 0;
}
return FALSE;
}
/**
* List gesture information
*
@ -594,7 +613,7 @@ ListDeviceClasses(ClientPtr client, DeviceIntPtr dev,
total_len += len;
}
if (dev->gesture) {
if (dev->gesture && ShouldListGestureInfo(client)) {
(*nclasses)++;
len = ListGestureInfo(dev, (xXIGestureInfo *) any);
any += len;