Do registration where it makes sense

src/platforms/evdev/libinput_device.cpp

@@ -104,28 +104,19 @@ auto get_axis_source(libinput_event_pointer* pointer) -> MirPointerAxisSource
     default:                                        return mir_pointer_axis_source_none;
     }
 }
+}
 
-class LibInputDeviceLedObserver : public mir::input::LedObserver
+void mie::LibInputDevice::leds_set(KeyboardLeds leds)
 {
-public:
-    explicit LibInputDeviceLedObserver(mie::LibInputDevice const* device) : device{device} {}
-
-    void leds_set(mir::input::KeyboardLeds leds) override
-    {
-        int led = 0;
-        if (contains(leds, mir::input::KeyboardLed::caps_lock))
-            led |= LIBINPUT_LED_CAPS_LOCK;
-        if (contains(leds, mir::input::KeyboardLed::num_lock))
-            led |= LIBINPUT_LED_NUM_LOCK;
-        if (contains(leds, mir::input::KeyboardLed::scroll_lock))
-            led |= LIBINPUT_LED_SCROLL_LOCK;
-
-        libinput_device_led_update(device->device(), static_cast<libinput_led>(led));
-    }
+    int led = 0;
+    if (contains(leds, mir::input::KeyboardLed::caps_lock))
+        led |= LIBINPUT_LED_CAPS_LOCK;
+    if (contains(leds, mir::input::KeyboardLed::num_lock))
+        led |= LIBINPUT_LED_NUM_LOCK;
+    if (contains(leds, mir::input::KeyboardLed::scroll_lock))
+        led |= LIBINPUT_LED_SCROLL_LOCK;
 
-private:
-    mie::LibInputDevice const* device;
-};
+    libinput_device_led_update(device(), static_cast<libinput_led>(led));
 }
 
 mie::LibInputDevice::LibInputDevice(std::shared_ptr<mi::InputReport> const& report, LibInputDevicePtr dev)

src/platforms/evdev/libinput_device.h

@@ -45,7 +45,7 @@ class OutputInfo;
 class InputReport;
 namespace evdev
 {
-class LibInputDevice : public input::InputDevice
+class LibInputDevice : public input::InputDevice, public mir::input::LedObserver
 {
 public:
     LibInputDevice(std::shared_ptr<InputReport> const& report, LibInputDevicePtr dev);
@@ -59,7 +59,8 @@ class LibInputDevice : public input::InputDevice
     void apply_settings(TouchpadSettings const&) override;
     optional_value<TouchscreenSettings> get_touchscreen_settings() const override;
     void apply_settings(TouchscreenSettings const&) override;
-    void associate_to_id(MirInputDeviceId id);
+
+    void leds_set(KeyboardLeds leds) override;
 
     void process_event(libinput_event* event);
     ::libinput_device* device() const;
@@ -104,7 +105,6 @@ class LibInputDevice : public input::InputDevice
     std::map<MirTouchId,ContactData> last_seen_properties;
 
     void update_contact_data(ContactData &data, MirTouchAction action, libinput_event_touch* touch);
-    void try_stop_observing_leds();
 };
 }
 }

src/platforms/evdev/platform.cpp

@@ -28,7 +28,6 @@
 
 #include "mir/input/input_device_registry.h"
 #include "mir/input/input_report.h"
-#include "mir/input/device.h"
 #include "mir/fd.h"
 #include "mir/raii.h"
 
@@ -432,9 +431,6 @@ void mie::Platform::device_added(libinput_device* dev)
 
         input_device_registry->add_device(devices.back());
 
-        if (auto device = weak_device.lock())
-            new_device->associate_to_id(device->id());
-
         log_info("Opened device: %s", describe(dev).c_str());
     }
     catch(...)

src/server/input/default_configuration.cpp

@@ -314,7 +314,8 @@ std::shared_ptr<mi::DefaultInputDeviceHub> mir::DefaultServerConfiguration::the_
                the_input_reading_multiplexer(),
                the_clock(),
                the_key_mapper(),
-               the_server_status_listener());
+               the_server_status_listener(),
+               the_led_observer_registrar());
 
            // lp:1675357: KeyRepeatDispatcher must be informed about removed input devices, otherwise
            // pressed keys get repeated indefinitely

src/server/input/default_input_device_hub.cpp

@@ -32,6 +32,8 @@
 #include "mir/log.h"
 
 #include "boost/throw_exception.hpp"
+#include "mir/input/led_observer_registrar.h"
+#include "mir/input/key_mapper.h"
 
 #include <algorithm>
 #include <atomic>
@@ -199,13 +201,15 @@ mi::DefaultInputDeviceHub::DefaultInputDeviceHub(
     std::shared_ptr<dispatch::MultiplexingDispatchable> const& input_multiplexer,
     std::shared_ptr<time::Clock> const& clock,
     std::shared_ptr<mi::KeyMapper> const& key_mapper,
-    std::shared_ptr<mir::ServerStatusListener> const& server_status_listener)
+    std::shared_ptr<mir::ServerStatusListener> const& server_status_listener,
+    std::shared_ptr<LedObserverRegistrar> led_observer_registrar)
     : seat{seat},
       input_dispatchable{input_multiplexer},
       device_queue(std::make_shared<dispatch::ActionQueue>()),
       clock(clock),
       key_mapper(key_mapper),
       server_status_listener(server_status_listener),
+      led_observer_registrar{std::move(led_observer_registrar)},
       device_id_generator{0}
 {
     input_dispatchable->add_watch(device_queue);
@@ -492,6 +496,11 @@ auto mi::DefaultInputDeviceHub::add_device(std::shared_ptr<InputDevice> const& d
         seat->add_device(*handle);
         dev->start(seat, input_dispatchable);
 
+        if (auto const observer = std::dynamic_pointer_cast<LedObserver>(device))
+        {
+            led_observer_registrar->register_interest(observer, handle->id());
+        }
+
         return handle;
     }
     else

src/server/input/default_input_device_hub.h

@@ -54,6 +54,7 @@ namespace input
 {
 class InputSink;
 class InputDeviceObserver;
+class LedObserverRegistrar;
 class DefaultDevice;
 class Seat;
 class KeyMapper;
@@ -86,7 +87,8 @@ class DefaultInputDeviceHub :
         std::shared_ptr<dispatch::MultiplexingDispatchable> const& input_multiplexer,
         std::shared_ptr<time::Clock> const& clock,
         std::shared_ptr<KeyMapper> const& key_mapper,
-        std::shared_ptr<ServerStatusListener> const& server_status_listener);
+        std::shared_ptr<ServerStatusListener> const& server_status_listener,
+        std::shared_ptr<LedObserverRegistrar> led_observer_registrar);
 
     // InputDeviceRegistry - calls from mi::Platform
     auto add_device(std::shared_ptr<InputDevice> const& device) -> std::weak_ptr<Device> override;
@@ -118,6 +120,7 @@ class DefaultInputDeviceHub :
     std::shared_ptr<time::Clock> const clock;
     std::shared_ptr<KeyMapper> const key_mapper;
     std::shared_ptr<ServerStatusListener> const server_status_listener;
+    std::shared_ptr<LedObserverRegistrar> const led_observer_registrar;
     ThreadSafeList<std::shared_ptr<InputDeviceObserver>> observers;
 
     /// Does not guarantee it's own threadsafety, non-const methods should not be called from multiple threads at once

tests/integration-tests/input/test_single_seat_setup.cpp

@@ -26,6 +26,7 @@
 #include "mir/test/doubles/mock_touch_visualizer.h"
 #include "mir/test/doubles/mock_cursor_listener.h"
 #include "mir/test/doubles/mock_input_manager.h"
+#include "mir/test/doubles/mock_led_observer_registrar.h"
 #include "mir/test/doubles/mock_seat_report.h"
 #include "mir/test/doubles/mock_server_status_listener.h"
 #include "mir/test/doubles/mock_scene_session.h"
@@ -97,6 +98,7 @@ struct SingleSeatInputDeviceHubSetup : ::testing::Test
     ms::SessionContainer session_container;
     ms::BroadcastingSessionEventSink session_event_sink;
     mtd::FakeDisplayConfigurationObserverRegistrar display_config;
+    NiceMock<mtd::MockLedObserverRegistrar> led_observer_registrar;
     mi::BasicSeat seat{mt::fake_shared(mock_dispatcher),      mt::fake_shared(mock_visualizer),
                        mt::fake_shared(mock_cursor_listener), mt::fake_shared(display_config),
                        mt::fake_shared(key_mapper),           mt::fake_shared(clock),
@@ -106,7 +108,8 @@ struct SingleSeatInputDeviceHubSetup : ::testing::Test
         mt::fake_shared(multiplexer),
         mt::fake_shared(clock),
         mt::fake_shared(key_mapper),
-        mt::fake_shared(mock_status_listener)};
+        mt::fake_shared(mock_status_listener),
+        mt::fake_shared(led_observer_registrar)};
     NiceMock<mtd::MockInputDeviceObserver> mock_observer;
     mi::ConfigChanger changer{
         mt::fake_shared(mock_input_manager),

tests/unit-tests/input/test_default_input_device_hub.cpp

@@ -21,6 +21,7 @@
 #include "mir/test/doubles/mock_input_seat.h"
 #include "mir/test/doubles/mock_event_sink.h"
 #include "mir/test/doubles/mock_key_mapper.h"
+#include "mir/test/doubles/mock_led_observer_registrar.h"
 #include "mir/test/doubles/mock_server_status_listener.h"
 #include "mir/test/doubles/advanceable_clock.h"
 #include "mir/test/fake_shared.h"
@@ -67,6 +68,7 @@ MATCHER_P(WithName, name,
 struct InputDeviceHubTest : ::testing::Test
 {
     mir::dispatch::MultiplexingDispatchable multiplexer;
+    NiceMock<mtd::MockLedObserverRegistrar> led_observer_registrar;
     NiceMock<mtd::MockInputSeat> mock_seat;
     NiceMock<mtd::MockKeyMapper> mock_key_mapper;
     NiceMock<mtd::MockServerStatusListener> mock_server_status_listener;
@@ -76,7 +78,8 @@ struct InputDeviceHubTest : ::testing::Test
         mt::fake_shared(multiplexer),
         mt::fake_shared(clock),
         mt::fake_shared(mock_key_mapper),
-        mt::fake_shared(mock_server_status_listener)};
+        mt::fake_shared(mock_server_status_listener),
+        mt::fake_shared(led_observer_registrar)};
     NiceMock<mtd::MockInputDeviceObserver> mock_observer;
     NiceMock<mtd::MockInputDevice> device{"device","dev-1", mi::DeviceCapability::unknown};
     NiceMock<mtd::MockInputDevice> another_device{"another_device","dev-2", mi::DeviceCapability::keyboard};