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XInputExtension (XInput) extension (partial)

Enumerates input devices beyond the core pointer/keyboard. Implements two XI1 query requests plus the XI2 version handshake and device query; XI2 event selection/delivery is not implemented yet (see Notes).

X.require('xinput', (err, XI) => {
    XI.XIQueryDevice(XI.AllDevices, (err, devices) => {
        devices.forEach(dev => {
            // {deviceId, use, attachment, enabled, name, classes}
            console.log(dev.deviceId, dev.name);
        });
    });
});

X.require first announces XI2 support with XIQueryVersion(2, 2) — result in XI.xi2 ({majorVersion, minorVersion}, or null on a pre-XI2 server, which remains usable for the XI1 requests) — then fetches the XI1 version into XI.serverMajor / XI.serverMinor.

Requests​

GetExtensionVersion(cb)​

XI1 (opcode 1). cb(err, {serverMajor, serverMinor, present}) — the XI1 version; present is 1 when the extension is available. Called automatically by X.require.

ListInputDevices(cb)​

XI1 (opcode 2). cb(err, devices) — array of {type, id, numClasses, use, attached, classes, name}. type is an atom (device type, often 0), use a XI.DeviceUse value, attached the id of the attached master (XI2 servers). classes is an array of {classId, ...} where classId is a XI.InputClass value:

  • Key → {minKeycode, maxKeycode, numKeys}
  • Button → {numButtons}
  • Valuator → {mode, motionBufferSize, axes: [{resolution, min, max}]}
  • other classes → {classId} only

XIQueryVersion(clientMajor, clientMinor, cb)​

XI2 (opcode 47). Announces the client's supported XI2 version; must precede any other XI2 request. cb(err, {majorVersion, minorVersion}) — what the server will speak. Called automatically by X.require with (2, 2).

XIQueryDevice(deviceId, cb)​

XI2 (opcode 48). deviceId is a device id, or XI.AllDevices (0) / XI.AllMasterDevices (1). cb(err, devices) — array of {deviceId, use, attachment, enabled, name, classes}. use is a XI.DeviceType value; attachment is the paired master (for master devices) or the master a slave is attached to. classes is an array of {type, sourceId, ...} where type is a XI.ClassType value:

  • Key → {keycodes} (array of keycodes)
  • Button → {numButtons, state, labels} (state — array of 32-bit mask words, labels — array of atoms, one per button)
  • Valuator → {number, label, min, max, value, resolution, mode} (min/max/value are FP3232 fixed point converted to Number)
  • Scroll → {number, scrollType, flags, increment}
  • Touch/Gesture → {type, sourceId} only (no per-class fields parsed)

Events​

None. XI2 events are GenericEvents (ext/ge.md) but no parser is registered in X.geEventParsers yet, and XISelectEvents is not implemented, so device events cannot be selected or parsed through this module (an unsolicited XI2 GenericEvent would surface as the generic {type: 35, extension, evtype, raw} shape).

Notes​

  • Not implemented: everything outside the four requests above — the XI1 device open/grab/event family (OpenDevice, GrabDevice, SelectExtensionEvent, ...) and the rest of XI2 (XISelectEvents, XIGrabDevice, XIGetClientPointer, XIChangeHierarchy, passive grabs, properties, barriers, ...).
  • Enums attached to the ext object: XI.DeviceUse = {IsXPointer: 0, IsXKeyboard: 1, IsXExtensionDevice: 2, IsXExtensionKeyboard: 3, IsXExtensionPointer: 4} (XI1), XI.InputClass = {Key: 0, Button: 1, Valuator: 2, Feedback: 3, Proximity: 4, Focus: 5, Other: 6} (XI1), XI.DeviceType = {MasterPointer: 1, MasterKeyboard: 2, SlavePointer: 3, SlaveKeyboard: 4, FloatingSlave: 5} (XI2), XI.ClassType = {Key: 0, Button: 1, Valuator: 2, Scroll: 3, Touch: 8, Gesture: 9} (XI2), plus XI.AllDevices = 0, XI.AllMasterDevices = 1.
  • FP3232 fixed-point fields become plain JS numbers (53-bit mantissa: fine for input axes).
  • Wire layouts are cross-checked against X11/extensions/XIproto.h and XI2proto.h.