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Generic Event Extension (GE)

Carries only a version handshake; its purpose is the GenericEvent (type 35) wire event that other extensions (Present, XInput2, ...) use to deliver events longer than the classic 32 bytes. Requiring ge is how a client announces it understands type-35 events.

X.require('ge', (err, GE) => {
    // GE.major / GE.minor — negotiated version (1.0)
});

The version is negotiated automatically while requiring; it is available as GE.major / GE.minor.

Requests​

QueryVersion(clientMajor, clientMinor, cb)​

Negotiates the protocol version. cb(err, [major, minor]) — the version the server will speak. Called automatically by X.require.

Events​

None of its own. GenericEvents are always defined (and parsed) by the extension that sends them; see below.

GenericEvent dispatch (X.geEventParsers)​

lib/xcore.js handles the type-35 wire format itself:

  • A GenericEvent header carries the sending extension's major opcode in byte 1 and an extra length (in 4-byte units) in bytes 4-7. The event body is 32 + extra * 4 bytes; xcore frames it by that length so variable-length events do not corrupt the reply stream.
  • The parsed event is produced by X.geEventParsers[majorOpcode], a map keyed by the sending extension's major opcode. An extension module registers its parser as X.geEventParsers[ext.majorOpcode] = (type, seq, extra, code, raw) => ... where type is 35, code is the major opcode, extra is the extra length, and raw is the event from byte 8 on (the 16-bit evtype selecting the extension's event is at raw offset 0).
  • With no parser registered the client still frames the event correctly and emits {type: 35, seq, extension, evtype, raw}.
  • As with all events, the full wire packet (here variable-length, not 32 bytes) is attached as event.rawData.

ext/present.md is the in-tree example of a registered parser; XInput2 events are not wired up yet (see ext/xinput.md).

Notes​

  • The spec requires clients to negotiate the version before relying on GenericEvents; X.require('ge', ...) does that. Extensions in this repo that send GenericEvents perform their own version handshakes, so requiring ge explicitly is only needed when talking to the wire format directly.