fix: Linux gamepad hotplug support, disconnect handling, and downcall fix (#79) - #80
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…tDevicePlugin - Trigger periodic refreshDevices() within getAll() so hotplugging works when starting with 0 devices - Add refreshDevices(boolean force) overload to allow plugins to immediately trigger discovery/cleanup - Update internal device collection before dispatching listeners so queries in callbacks observe the updated state - Ensure thread safety with synchronized refreshDevices() and CopyOnWriteArrayList
…sconnect errnos - Fix HANDLE_WRITE return type to JAVA_INT matching HANDLE_READ and polymorphic invoke - Add EBADF (9) and ENODEV (19) errno constants with unit test assertions - Treat EBADF and ENODEV as expected disconnections in Linux.invoke instead of logging SEVERE - Add overloaded read method supporting pre-allocated memory segments
…allocation polling - Implement refreshInputDevices() to scan /dev/input/event*, register newly connected devices, and remove disconnected ones - Automatically trigger refreshDevices() from pollLinuxEventDevice() - Detect ENODEV and EBADF on event read, immediately marking devices disconnected and forcing device refresh - Prevent file descriptor leaks by immediately closing discarded devices during scan - Prevent double-close in LinuxEventDevice and skip rumble stop calls on already-disconnected devices - Pre-allocate event structures and errno buffer per device to achieve zero-allocation polling in shared arena
… detection - Add isGamepadOrJoystick() heuristic checking EV_KEY and EV_ABS bitmasks - Accept standard gamepad/joystick buttons (BTN_GAMEPAD, BTN_JOYSTICK, BTN_TRIGGER_HAPPY, BTN_0..9, BTN_WHEEL, BTN_DPAD_*) - Accept flight stick, rudder, throttle, wheel, gas, brake, and hat axes - Reject touchpads (BTN_TOUCH, BTN_TOOL_FINGER), mice (BTN_MOUSE..BTN_TASK), and keyboards without gamepad buttons - Add bounds checking to LinuxEventDevice.isBitSet() to guard against short bitmask arrays - Add comprehensive unit test suite covering gamepads, flight sticks, rudder pedals, touchpads, and mice
…te downcalls - Define ssizeT = IS_32_BIT ? JAVA_INT : JAVA_LONG to accurately match POSIX ssize_t across architectures - Update FunctionDescriptor return types for read and write to ssizeT - Handle long.class return types in invokeWithCapturedState without WrongMethodTypeException - Add regression tests verifying downcall handle return types match architecture ssize_t
…and periodic refresh - Probe candidate event device nodes inside try-with-resources Arena.ofConfined() so non-gamepad devices leave zero off-heap memory behind - Allocate a dedicated Arena.ofShared() only when a candidate node is confirmed as a gamepad/joystick - Close the per-device arena when the device is disconnected or closed, reclaiming 100% of native resources - Pre-allocate versionSegment and versionCapturedState in LinuxEventDevice to make periodic liveness checks completely allocation-free - Use Arena.ofConfined() for force-feedback rumble effect upload, playback, and removal to prevent off-heap growth during rumble - Remove plugin-level shared arena from LinuxEventDevicePlugin - Add regression tests for candidate probe arena lifecycle, device disconnection, and arena closing
…ble-close in try-with-resources
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Fixes #79
Overview
Resolves several interrelated issues on Linux where gamepad connections and disconnections were not detected, downcalls to
write/setGaincaused a JVMWrongMethodTypeException, laptop touchpads/mice were falsely registered as controllers, and polling caused unbounded off-heap memory allocations.Problems & Solutions
1. Gamepad Connects and Disconnects Not Registering
LinuxEventDevicePlugin.refreshInputDevices()was an unpopulated stub. In addition,AbstractInputDevicePlugin.getAll()never triggeredrefreshDevices(), preventing discovery if an application started with 0 gamepads connected.LinuxEventDevicePlugin.refreshInputDevices()to scan/dev/input/event*, register newly connected devices, detect disconnected devices viaEVIOCGVERSION, and prune stale entries.refreshDevices()checks inAbstractInputDevicePlugin.getAll().refreshDevices(boolean force)to allow instant, out-of-band discovery/cleanup without waiting forhotPlugIntervalto expire.AbstractInputDevicePluginto commit internal device lists before dispatching connect/disconnect/change listeners so listener callbacks queryingInputDevices.getDevices()orgetAll()observe the updated state.2.
WrongMethodTypeExceptionon Linuxwrite/setGainLinux.java,HANDLE_WRITEwas configured with a return type ofsizeT(JAVA_LONGon 64-bit platforms), but downcall call sites cast the polymorphic invoke result to(int). This threwjava.lang.invoke.WrongMethodTypeException: cannot adapt long to intwhenever rumble effects or gain were updated.HANDLE_WRITE's function descriptor return type toJAVA_INTmatchingHANDLE_READandinvoke().3. File Descriptor Exhaustion & Disconnect Log Spam
/dev/input/event*opened devices that were discarded (e.g. video buses, HDMI, or devices without required components) without closing them, leading to file descriptor leaks. Furthermore, when a device was unplugged, subsequent operations logged continuousLevel.SEVEREerrors.device.close(this.memoryArena)on all ignored or discarded device nodes during discovery.EBADF(9) andENODEV(19) errno constants. When detected duringreadEvent(), devices are marked disconnected,refreshDevices(true)is triggered immediately, and logs are downgraded toLevel.FINE.closedguard inLinuxEventDevice.close()to prevent double-closing and skip sending rumble stop commands to nodes already detached by the kernel.4. Zero-Allocation Polling in Shared Arenas
Linux.read(Arena, fd)allocated aninput_eventlayout and captured state layout on every single event intomemoryArena(a shared arena that lives for the lifetime of the plugin), creating unbounded off-heap native memory growth.inputEventSegment,capturedStateSegment, and an errno buffer perLinuxEventDeviceinstance, eliminating native heap allocations inside the hot polling loop.5. False-Positive Controller Detection (Touchpads, Mice, Keyboards)
SYNA30D2:00 Touchpadfrom issue logs) and mice exposeABS_X/ABS_YandBTN_LEFT, satisfying the previous naiveanyMatch(BUTTON || AXIS)check and registering as game controllers.LinuxEventDevicePlugin.isGamepadOrJoystick(keyBits, absBits)implementing kernel evdev heuristics:BTN_GAMEPAD,BTN_JOYSTICK,BTN_TRIGGER_HAPPY,BTN_0..9,BTN_WHEEL,BTN_DPAD_*).BTN_TOUCH,BTN_TOOL_FINGER,BTN_TOOL_DOUBLETAP, etc.), mice (BTN_LEFT..BTN_TASK), and keyboards lacking gamepad buttons.LinuxEventDevice.isBitSet().Changes by Commit
f887c59feat: improve hotplug lifecycle and event consistency in AbstractInputDevicePlugin7dea2aefix(linux): fix WrongMethodTypeException on write downcall and add disconnect errnos61a2ac7feat(linux): implement device hotplug, disconnect handling, and zero-allocation pollingf52662cfix(linux): filter out touchpads, mice, and keyboards from controller detectionVerification & Testing
AbstractInputDevicePluginTests: Validates initialization checks,onDeviceConnected,onDeviceDisconnected,onDevicesChanged,hotPlugIntervalexpiry, and listener cleanup onclose().LinuxEventDevicePluginTests: Comprehensive unit tests forisGamepadOrJoystickcovering Xbox controllers, flight sticks, arcade fight sticks, rudder pedals, hat switches, DualShock 4 with integrated touchpads, and rejecting laptop trackpads, mice, and keyboards.LinuxPermissionTests: ValidatesEBADFandENODEVerrno mappings../gradlew build: SUCCESSFUL (all unit tests and tasks passing)../gradlew spotlessCheck: SUCCESSFUL (enforces Google Java Format).