input_testing/

lib.rs

// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use async_utils::event::Event as AsyncEvent;
use fidl_fuchsia_input::Key;
use fidl_fuchsia_input_injection::InputDeviceRegistryMarker;
use fidl_fuchsia_input_report::{
    ConsumerControlInputReport, ContactInputReport, DeviceInformation, InputReport,
    KeyboardInputReport, MouseInputReport, TouchInputReport,
};
use fidl_fuchsia_ui_input::KeyboardReport;
use fidl_fuchsia_ui_test_input::{
    CoordinateUnit, KeyboardMarker, KeyboardRequest, KeyboardRequestStream,
    MediaButtonsDeviceMarker, MediaButtonsDeviceRequest, MediaButtonsDeviceRequestStream,
    MouseMarker, MouseRequest, MouseRequestStream,
    RegistryRegisterKeyboardAndGetDeviceInfoResponse,
    RegistryRegisterMediaButtonsDeviceAndGetDeviceInfoResponse,
    RegistryRegisterMouseAndGetDeviceInfoResponse,
    RegistryRegisterTouchScreenAndGetDeviceInfoResponse, RegistryRequest, RegistryRequestStream,
    TouchScreenMarker, TouchScreenRequest, TouchScreenRequestStream,
};
use fuchsia_component::client::connect_to_protocol;
use futures::{StreamExt, TryStreamExt};
use keymaps::inverse_keymap::{InverseKeymap, Shift};
use keymaps::usages::{hid_usage_to_input3_key, Usages};
use std::time::Duration;
use tracing::{error, info, warn};
use {
    fidl_fuchsia_math as math, fidl_fuchsia_ui_display_singleton as display_info,
    fuchsia_async as fasync,
};

mod input_device;
mod input_device_registry;
mod input_reports_reader;

/// Use this to place required DeviceInformation into DeviceDescriptor.
fn new_fake_device_info() -> DeviceInformation {
    DeviceInformation {
        product_id: Some(42),
        vendor_id: Some(43),
        version: Some(u32::MAX),
        polling_rate: Some(1000),
        ..Default::default()
    }
}

/// Converts the `input` string into a key sequence under the `InverseKeymap` derived from `keymap`.
///
/// This is intended for end-to-end and input testing only; for production use cases and general
/// testing, IME injection should be used instead.
///
/// A translation from `input` to a sequence of keystrokes is not guaranteed to exist. If a
/// translation does not exist, `None` is returned.
///
/// The sequence does not contain pauses except between repeated keys or to clear a shift state,
/// though the sequence does terminate with an empty report (no keys pressed). A shift key
/// transition is sent in advance of each series of keys that needs it.
///
/// Note that there is currently no way to distinguish between particular key releases. As such,
/// only one key release report is generated even in combinations, e.g. Shift + A.
///
/// # Example
///
/// ```
/// let key_sequence = derive_key_sequence(&keymaps::US_QWERTY, "A").unwrap();
///
/// // [shift, A, clear]
/// assert_eq!(key_sequence.len(), 3);
/// ```
///
/// TODO(https://fxbug.dev/42059899): Simplify the logic in this test.
fn derive_key_sequence(keymap: &keymaps::Keymap<'_>, input: &str) -> Option<Vec<KeyboardReport>> {
    let inverse_keymap = InverseKeymap::new(keymap);
    let mut reports = vec![];
    let mut shift_pressed = false;
    let mut last_usage = None;

    for ch in input.chars() {
        let key_stroke = inverse_keymap.get(&ch)?;

        match key_stroke.shift {
            Shift::Yes if !shift_pressed => {
                shift_pressed = true;
                last_usage = Some(0);
            }
            Shift::No if shift_pressed => {
                shift_pressed = false;
                last_usage = Some(0);
            }
            _ => {
                if last_usage == Some(key_stroke.usage) {
                    last_usage = Some(0);
                }
            }
        }

        if let Some(0) = last_usage {
            reports.push(KeyboardReport {
                pressed_keys: if shift_pressed {
                    vec![Usages::HidUsageKeyLeftShift as u32]
                } else {
                    vec![]
                },
            });
        }

        last_usage = Some(key_stroke.usage);

        reports.push(KeyboardReport {
            pressed_keys: if shift_pressed {
                vec![key_stroke.usage, Usages::HidUsageKeyLeftShift as u32]
            } else {
                vec![key_stroke.usage]
            },
        });
    }

    reports.push(KeyboardReport { pressed_keys: vec![] });

    Some(reports)
}

fn convert_keyboard_report_to_keys(report: &KeyboardReport) -> Vec<Key> {
    report
        .pressed_keys
        .iter()
        .map(|&usage| {
            hid_usage_to_input3_key(usage.try_into().expect("failed to convert usage to u16"))
                .unwrap_or_else(|| panic!("no Key for usage {:?}", usage))
        })
        .collect()
}

async fn register_touch_screen(
    mut registry: input_device_registry::InputDeviceRegistry,
    task_group: &mut fasync::TaskGroup,
    device_server_end: fidl::endpoints::ServerEnd<TouchScreenMarker>,
    got_input_reports_reader: AsyncEvent,
    min_x: i64,
    max_x: i64,
    min_y: i64,
    max_y: i64,
) -> input_device::DeviceId {
    let device = registry
        .add_touchscreen_device(min_x, max_x, min_y, max_y)
        .await
        .expect("failed to create fake touchscreen device");
    let device_id = device.device_id;

    task_group.spawn(async move {
        handle_touchscreen_request_stream(device, device_server_end.into_stream()).await;
    });

    info!("wait for input-pipeline setup input-reader");
    let _ = got_input_reports_reader.wait().await;
    info!("input-pipeline setup input-reader.");

    device_id
}

async fn register_media_button(
    mut registry: input_device_registry::InputDeviceRegistry,
    task_group: &mut fasync::TaskGroup,
    device_server_end: fidl::endpoints::ServerEnd<MediaButtonsDeviceMarker>,
    got_input_reports_reader: AsyncEvent,
) -> input_device::DeviceId {
    let device = registry
        .add_media_buttons_device()
        .await
        .expect("failed to create fake media buttons device");
    let device_id = device.device_id;

    task_group.spawn(async move {
        handle_media_buttons_device_request_stream(device, device_server_end.into_stream()).await;
    });

    info!("wait for input-pipeline setup input-reader");
    let _ = got_input_reports_reader.wait().await;
    info!("input-pipeline setup input-reader.");

    device_id
}

async fn register_keyboard(
    mut registry: input_device_registry::InputDeviceRegistry,
    task_group: &mut fasync::TaskGroup,
    device_server_end: fidl::endpoints::ServerEnd<KeyboardMarker>,
    got_input_reports_reader: AsyncEvent,
) -> input_device::DeviceId {
    let device = registry.add_keyboard_device().await.expect("failed to create fake keyboard");
    let device_id = device.device_id;

    task_group.spawn(async move {
        handle_keyboard_request_stream(device, device_server_end.into_stream()).await;
    });

    info!("wait for input-pipeline setup input-reader");
    let _ = got_input_reports_reader.wait().await;
    info!("input-pipeline setup input-reader.");

    device_id
}

async fn register_mouse(
    mut registry: input_device_registry::InputDeviceRegistry,
    task_group: &mut fasync::TaskGroup,
    device_server_end: fidl::endpoints::ServerEnd<MouseMarker>,
    got_input_reports_reader: AsyncEvent,
) -> input_device::DeviceId {
    let device = registry.add_mouse_device().await.expect("failed to create fake mouse");
    let device_id = device.device_id;

    task_group.spawn(async move {
        handle_mouse_request_stream(device, device_server_end.into_stream()).await;
    });

    info!("wait for input-pipeline setup input-reader");
    let _ = got_input_reports_reader.wait().await;
    info!("input-pipeline setup input-reader.");

    device_id
}

/// Serves `fuchsia.ui.test.input.Registry`.
pub async fn handle_registry_request_stream(request_stream: RegistryRequestStream) {
    request_stream
        .try_for_each_concurrent(None, |request| async {
            let input_device_registry = connect_to_protocol::<InputDeviceRegistryMarker>()
                .expect("connect to input_device_registry");
            let got_input_reports_reader = AsyncEvent::new();

            let registry = input_device_registry::InputDeviceRegistry::new(
                input_device_registry,
                got_input_reports_reader.clone(),
            );
            let mut task_group = fasync::TaskGroup::new();

            match request {
                RegistryRequest::RegisterTouchScreen { payload, responder, .. } => {
                    info!("register touchscreen");
                    let device = payload
                        .device
                        .expect("no touchscreen device provided in registration request");
                    let (min_x, max_x, min_y, max_y) = match payload.coordinate_unit {
                        Some(CoordinateUnit::PhysicalPixels) => {
                            let display_info_proxy =
                                connect_to_protocol::<display_info::InfoMarker>()
                                    .expect("failed to connect to display info service");
                            let display_dimensions = display_info_proxy
                                .get_metrics()
                                .await
                                .expect("failed to get display metrics")
                                .extent_in_px
                                .expect("display metrics missing extent in px");
                            (
                                0,
                                display_dimensions.width as i64,
                                0,
                                display_dimensions.height as i64,
                            )
                        }
                        _ => (-1000, 1000, -1000, 1000),
                    };

                    register_touch_screen(
                        registry,
                        &mut task_group,
                        device,
                        got_input_reports_reader,
                        min_x,
                        max_x,
                        min_y,
                        max_y,
                    )
                    .await;

                    responder.send().expect("Failed to respond to RegisterTouchScreen request");
                }
                RegistryRequest::RegisterTouchScreenAndGetDeviceInfo {
                    payload, responder, ..
                } => {
                    info!("register touchscreen");
                    let device = payload
                        .device
                        .expect("no touchscreen device provided in registration request");
                    let (min_x, max_x, min_y, max_y) = match payload.coordinate_unit {
                        Some(CoordinateUnit::PhysicalPixels) => {
                            let display_info_proxy =
                                connect_to_protocol::<display_info::InfoMarker>()
                                    .expect("failed to connect to display info service");
                            let display_dimensions = display_info_proxy
                                .get_metrics()
                                .await
                                .expect("failed to get display metrics")
                                .extent_in_px
                                .expect("display metrics missing extent in px");
                            (
                                0,
                                display_dimensions.width as i64,
                                0,
                                display_dimensions.height as i64,
                            )
                        }
                        _ => (-1000, 1000, -1000, 1000),
                    };

                    let device_id = register_touch_screen(
                        registry,
                        &mut task_group,
                        device,
                        got_input_reports_reader,
                        min_x,
                        max_x,
                        min_y,
                        max_y,
                    )
                    .await;

                    responder
                        .send(RegistryRegisterTouchScreenAndGetDeviceInfoResponse {
                            device_id: Some(device_id),
                            ..Default::default()
                        })
                        .expect("Failed to respond to RegisterTouchScreenAndGetDeviceInfo request");
                }
                RegistryRequest::RegisterMediaButtonsDevice { payload, responder, .. } => {
                    info!("register media buttons device");
                    let device = payload
                        .device
                        .expect("no media buttons device provided in registration request");

                    register_media_button(
                        registry,
                        &mut task_group,
                        device,
                        got_input_reports_reader,
                    )
                    .await;

                    responder
                        .send()
                        .expect("Failed to respond to RegisterMediaButtonsDevice request");
                }
                RegistryRequest::RegisterMediaButtonsDeviceAndGetDeviceInfo {
                    payload,
                    responder,
                    ..
                } => {
                    info!("register media buttons device");
                    let device = payload
                        .device
                        .expect("no media buttons device provided in registration request");

                    let device_id = register_media_button(
                        registry,
                        &mut task_group,
                        device,
                        got_input_reports_reader,
                    )
                    .await;

                    responder.send(RegistryRegisterMediaButtonsDeviceAndGetDeviceInfoResponse {
                        device_id: Some(device_id),
                        ..Default::default()
                    }).expect(
                        "Failed to respond to RegisterMediaButtonsDeviceAndGetDeviceInfo request",
                    );
                }
                RegistryRequest::RegisterKeyboard { payload, responder, .. } => {
                    info!("register keyboard device");
                    let device = payload
                        .device
                        .expect("no keyboard device provided in registration request");

                    register_keyboard(registry, &mut task_group, device, got_input_reports_reader)
                        .await;

                    responder.send().expect("Failed to respond to RegisterKeyboard request");
                }
                RegistryRequest::RegisterKeyboardAndGetDeviceInfo {
                    payload, responder, ..
                } => {
                    info!("register keyboard device");
                    let device = payload
                        .device
                        .expect("no keyboard device provided in registration request");

                    let device_id = register_keyboard(
                        registry,
                        &mut task_group,
                        device,
                        got_input_reports_reader,
                    )
                    .await;

                    responder
                        .send(RegistryRegisterKeyboardAndGetDeviceInfoResponse {
                            device_id: Some(device_id),
                            ..Default::default()
                        })
                        .expect("Failed to respond to RegisterKeyboardAndGetDeviceInfo request");
                }
                RegistryRequest::RegisterMouse { payload, responder } => {
                    info!("register mouse device");
                    let device = payload.device.expect("no mouse provided in registration request");

                    register_mouse(registry, &mut task_group, device, got_input_reports_reader)
                        .await;

                    responder.send().expect("Failed to respond to RegisterMouse request");
                }
                RegistryRequest::RegisterMouseAndGetDeviceInfo { payload, responder } => {
                    info!("register mouse device");
                    let device = payload.device.expect("no mouse provided in registration request");

                    let device_id =
                        register_mouse(registry, &mut task_group, device, got_input_reports_reader)
                            .await;

                    responder
                        .send(RegistryRegisterMouseAndGetDeviceInfoResponse {
                            device_id: Some(device_id),
                            ..Default::default()
                        })
                        .expect("Failed to respond to RegisterMouse request");
                }
            }

            task_group.join().await;
            Ok(())
        })
        .await
        .expect("failed to serve test realm factory request stream");
}

fn input_report_for_touch_contacts(contacts: Vec<(u32, math::Vec_)>) -> InputReport {
    let contact_input_reports = contacts
        .into_iter()
        .map(|(contact_id, location)| ContactInputReport {
            contact_id: Some(contact_id),
            position_x: Some(location.x as i64),
            position_y: Some(location.y as i64),
            contact_width: Some(0),
            contact_height: Some(0),
            ..Default::default()
        })
        .collect();

    let touch_input_report = TouchInputReport {
        contacts: Some(contact_input_reports),
        pressed_buttons: Some(vec![]),
        ..Default::default()
    };

    InputReport {
        event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
        touch: Some(touch_input_report),
        ..Default::default()
    }
}

/// Serves `fuchsia.ui.test.input.TouchScreen`.
async fn handle_touchscreen_request_stream(
    touchscreen_device: input_device::InputDevice,
    mut request_stream: TouchScreenRequestStream,
) {
    while let Some(request) = request_stream.next().await {
        match request {
            Ok(TouchScreenRequest::SimulateTap { payload, responder }) => {
                if let Some(tap_location) = payload.tap_location {
                    touchscreen_device
                        .send_input_report(input_report_for_touch_contacts(vec![(1, tap_location)]))
                        .expect("Failed to send tap input report");

                    // Send a report with an empty set of touch contacts, so that input
                    // pipeline generates a pointer event with phase == UP.
                    touchscreen_device
                        .send_input_report(input_report_for_touch_contacts(vec![]))
                        .expect("failed to send empty input report");

                    responder.send().expect("Failed to send SimulateTap response");
                } else {
                    warn!("SimulateTap request missing tap location");
                }
            }
            Ok(TouchScreenRequest::SimulateSwipe { payload, responder }) => {
                // Compute the x- and y- displacements between successive touch events.
                let start_location = payload.start_location.expect("missing start location");
                let end_location = payload.end_location.expect("missing end location");
                let move_event_count = payload.move_event_count.expect("missing move event count");
                assert_ne!(move_event_count, 0);

                let start_x_f = start_location.x as f64;
                let start_y_f = start_location.y as f64;
                let end_x_f = end_location.x as f64;
                let end_y_f = end_location.y as f64;
                let move_event_count_f = move_event_count as f64;
                let step_size_x = (end_x_f - start_x_f) / move_event_count_f;
                let step_size_y = (end_y_f - start_y_f) / move_event_count_f;

                // Generate an event at `start_location`, followed by `move_event_count - 1`
                // evenly-spaced events, followed by an event at `end_location`.
                for i in 0..move_event_count + 1 {
                    let i_f = i as f64;
                    let event_x = start_x_f + (i_f * step_size_x);
                    let event_y = start_y_f + (i_f * step_size_y);
                    touchscreen_device
                        .send_input_report(input_report_for_touch_contacts(vec![(
                            1,
                            math::Vec_ { x: event_x as i32, y: event_y as i32 },
                        )]))
                        .expect("Failed to send tap input report");
                }

                // Send a report with an empty set of touch contacts, so that input
                // pipeline generates a pointer event with phase == UP.
                touchscreen_device
                    .send_input_report(input_report_for_touch_contacts(vec![]))
                    .expect("failed to send empty input report");

                responder.send().expect("Failed to send SimulateSwipe response");
            }
            Ok(TouchScreenRequest::SimulateMultiTap { payload, responder }) => {
                let tap_locations = payload.tap_locations.expect("missing tap locations");
                touchscreen_device
                    .send_input_report(input_report_for_touch_contacts(
                        tap_locations
                            .into_iter()
                            .enumerate()
                            .map(|(i, it)| (i as u32, it))
                            .collect(),
                    ))
                    .expect("Failed to send tap input report");

                // Send a report with an empty set of touch contacts, so that input
                // pipeline generates a pointer event with phase == UP.
                touchscreen_device
                    .send_input_report(input_report_for_touch_contacts(vec![]))
                    .expect("failed to send empty input report");
                responder.send().expect("Failed to send SimulateMultiTap response");
            }
            Ok(TouchScreenRequest::SimulateMultiFingerGesture { payload, responder }) => {
                // Compute the x- and y- displacements between successive touch events.
                let start_locations = payload.start_locations.expect("missing start locations");
                let end_locations = payload.end_locations.expect("missing end locations");
                let move_event_count = payload.move_event_count.expect("missing move event count");
                let finger_count = payload.finger_count.expect("missing finger count") as usize;

                let move_event_count_f = move_event_count as f32;

                let mut steps: Vec<math::VecF> = vec![];

                for finger in 0..finger_count {
                    let start_x = start_locations[finger].x as f32;
                    let start_y = start_locations[finger].y as f32;
                    let end_x = end_locations[finger].x as f32;
                    let end_y = end_locations[finger].y as f32;
                    let step_x = (end_x - start_x) / move_event_count_f;
                    let step_y = (end_y - start_y) / move_event_count_f;
                    steps.push(math::VecF { x: step_x, y: step_y });
                }

                // Generate an event at `start_location`, followed by `move_event_count - 1`
                // evenly-spaced events, followed by an event at `end_location`.
                for i in 0..move_event_count {
                    let i_f = i as f32;

                    let mut contacts: Vec<(u32, math::Vec_)> = vec![];

                    for finger in 0..finger_count {
                        let start_x = start_locations[finger].x as f32;
                        let start_y = start_locations[finger].y as f32;
                        let event_x = (start_x + i_f * steps[finger].x) as i32;
                        let event_y = (start_y + i_f * steps[finger].y) as i32;
                        contacts.push((finger as u32, math::Vec_ { x: event_x, y: event_y }));
                    }

                    touchscreen_device
                        .send_input_report(input_report_for_touch_contacts(contacts))
                        .expect("Failed to send tap input report");
                }

                // Send a report with an empty set of touch contacts, so that input
                // pipeline generates a pointer event with phase == UP.
                touchscreen_device
                    .send_input_report(input_report_for_touch_contacts(vec![]))
                    .expect("failed to send empty input report");

                responder.send().expect("Failed to send SimulateMultiFingerGesture response");
            }
            Ok(TouchScreenRequest::SimulateTouchEvent { report, responder }) => {
                let input_report = InputReport {
                    event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
                    touch: Some(report),
                    ..Default::default()
                };
                touchscreen_device
                    .send_input_report(input_report)
                    .expect("failed to send empty input report");
                responder.send().expect("Failed to send SimulateTouchEvent response");
            }
            Err(e) => {
                error!("Error on touchscreen channel: {}", e);
                return;
            }
        }
    }
}

/// Serves `fuchsia.ui.test.input.MediaButtonsDevice`.
async fn handle_media_buttons_device_request_stream(
    media_buttons_device: input_device::InputDevice,
    mut request_stream: MediaButtonsDeviceRequestStream,
) {
    while let Some(request) = request_stream.next().await {
        match request {
            Ok(MediaButtonsDeviceRequest::SimulateButtonPress { payload, responder }) => {
                if let Some(button) = payload.button {
                    let media_buttons_input_report = ConsumerControlInputReport {
                        pressed_buttons: Some(vec![button]),
                        ..Default::default()
                    };

                    let input_report = InputReport {
                        event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
                        consumer_control: Some(media_buttons_input_report),
                        ..Default::default()
                    };

                    media_buttons_device
                        .send_input_report(input_report)
                        .expect("Failed to send button press input report");

                    // Send a report with an empty set of pressed buttons,
                    // so that input pipeline generates a media buttons
                    // event with the target button being released.
                    let empty_report = InputReport {
                        event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
                        consumer_control: Some(ConsumerControlInputReport {
                            pressed_buttons: Some(vec![]),
                            ..Default::default()
                        }),
                        ..Default::default()
                    };

                    media_buttons_device
                        .send_input_report(empty_report)
                        .expect("Failed to send button release input report");

                    responder.send().expect("Failed to send SimulateButtonPress response");
                } else {
                    warn!("SimulateButtonPress request missing button");
                }
            }
            Ok(MediaButtonsDeviceRequest::SendButtonsState { payload, responder }) => {
                let buttons = match payload.buttons {
                    Some(buttons) => buttons,
                    None => vec![],
                };
                let input_report = InputReport {
                    event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
                    consumer_control: Some(ConsumerControlInputReport {
                        pressed_buttons: Some(buttons),
                        ..Default::default()
                    }),
                    ..Default::default()
                };

                media_buttons_device
                    .send_input_report(input_report)
                    .expect("Failed to send button press input report");

                responder.send().expect("Failed to send SimulateButtonsPress response");
            }
            Err(e) => {
                error!("Error on media buttons device channel: {}", e);
                return;
            }
        }
    }
}

/// Serves `fuchsia.ui.test.input.Keyboard`.
async fn handle_keyboard_request_stream(
    keyboard_device: input_device::InputDevice,
    mut request_stream: KeyboardRequestStream,
) {
    while let Some(request) = request_stream.next().await {
        match request {
            Ok(KeyboardRequest::SimulateUsAsciiTextEntry { payload, responder }) => {
                if let Some(text) = payload.text {
                    let key_sequence = derive_key_sequence(&keymaps::US_QWERTY, &text)
                        .expect("Failed to derive key sequence");

                    let mut key_iter = key_sequence.into_iter().peekable();
                    while let Some(keyboard_report) = key_iter.next() {
                        let input_report = InputReport {
                            event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
                            keyboard: Some(KeyboardInputReport {
                                pressed_keys3: Some(convert_keyboard_report_to_keys(
                                    &keyboard_report,
                                )),
                                ..Default::default()
                            }),
                            ..Default::default()
                        };

                        keyboard_device
                            .send_input_report(input_report)
                            .expect("Failed to send key event report");

                        if key_iter.peek().is_some() {
                            fuchsia_async::Timer::new(Duration::from_millis(100)).await;
                        }
                    }

                    responder.send().expect("Failed to send SimulateTextEntry response");
                } else {
                    warn!("SimulateTextEntry request missing text");
                }
            }
            Ok(KeyboardRequest::SimulateKeyEvent { payload, responder }) => {
                let keyboard_report = payload.report.expect("no report");
                let input_report = InputReport {
                    event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
                    keyboard: Some(keyboard_report),
                    ..Default::default()
                };

                keyboard_device
                    .send_input_report(input_report)
                    .expect("Failed to send key event report");

                responder.send().expect("Failed to send SimulateKeyEvent response");
            }
            Err(e) => {
                error!("Error on keyboard device channel: {}", e);
                return;
            }
        }
    }
}

/// Serves `fuchsia.ui.test.input.Mouse`.
async fn handle_mouse_request_stream(
    mouse_device: input_device::InputDevice,
    mut request_stream: MouseRequestStream,
) {
    while let Some(request) = request_stream.next().await {
        match request {
            Ok(MouseRequest::SimulateMouseEvent { payload, responder }) => {
                let mut mouse_input_report = MouseInputReport {
                    movement_x: payload.movement_x,
                    movement_y: payload.movement_y,
                    scroll_v: payload.scroll_v_detent,
                    scroll_h: payload.scroll_h_detent,
                    ..Default::default()
                };
                if let Some(pressed_buttons) = payload.pressed_buttons {
                    mouse_input_report.pressed_buttons = Some(
                        pressed_buttons
                            .into_iter()
                            .map(|b| {
                                b.into_primitive()
                                    .try_into()
                                    .expect("failed to convert MouseButton to u8")
                            })
                            .collect(),
                    );
                }

                let input_report = InputReport {
                    event_time: Some(fasync::MonotonicInstant::now().into_nanos()),
                    mouse: Some(mouse_input_report),
                    ..Default::default()
                };

                mouse_device
                    .send_input_report(input_report)
                    .expect("Failed to send key event report");

                responder.send().expect("Failed to send SimulateMouseEvent response");
            }
            Err(e) => {
                error!("Error on keyboard device channel: {}", e);
                return;
            }
        }
    }
}

#[cfg(test)]
mod tests {
    // Most of the functions in this file need to bind to FIDL services in
    // this component's environment to do their work, but a component can't
    // modify its own environment. Hence, we can't validate those functions.
    //
    // However, we can (and do) validate derive_key_sequence().

    use super::{derive_key_sequence, KeyboardReport, Usages};
    use pretty_assertions::assert_eq;

    // TODO(https://fxbug.dev/42059899): Remove this macro.
    macro_rules! reports {
        ( $( [ $( $usages:expr ),* ] ),* $( , )? ) => {
            Some(vec![
                $(
                    KeyboardReport {
                        pressed_keys: vec![$($usages as u32),*]
                    }
                ),*
            ])
        }
    }

    #[test]
    fn lowercase() {
        assert_eq!(
            derive_key_sequence(&keymaps::US_QWERTY, "lowercase"),
            reports![
                [Usages::HidUsageKeyL],
                [Usages::HidUsageKeyO],
                [Usages::HidUsageKeyW],
                [Usages::HidUsageKeyE],
                [Usages::HidUsageKeyR],
                [Usages::HidUsageKeyC],
                [Usages::HidUsageKeyA],
                [Usages::HidUsageKeyS],
                [Usages::HidUsageKeyE],
                [],
            ]
        );
    }

    #[test]
    fn numerics() {
        assert_eq!(
            derive_key_sequence(&keymaps::US_QWERTY, "0123456789"),
            reports![
                [Usages::HidUsageKey0],
                [Usages::HidUsageKey1],
                [Usages::HidUsageKey2],
                [Usages::HidUsageKey3],
                [Usages::HidUsageKey4],
                [Usages::HidUsageKey5],
                [Usages::HidUsageKey6],
                [Usages::HidUsageKey7],
                [Usages::HidUsageKey8],
                [Usages::HidUsageKey9],
                [],
            ]
        );
    }

    #[test]
    fn internet_text_entry() {
        assert_eq!(
            derive_key_sequence(&keymaps::US_QWERTY, "http://127.0.0.1:8080"),
            reports![
                [Usages::HidUsageKeyH],
                [Usages::HidUsageKeyT],
                [],
                [Usages::HidUsageKeyT],
                [Usages::HidUsageKeyP],
                // ':'
                // Shift is actuated first on its own, then together with
                // the key.
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeySemicolon, Usages::HidUsageKeyLeftShift],
                [],
                [Usages::HidUsageKeySlash],
                [],
                [Usages::HidUsageKeySlash],
                [Usages::HidUsageKey1],
                [Usages::HidUsageKey2],
                [Usages::HidUsageKey7],
                [Usages::HidUsageKeyDot],
                [Usages::HidUsageKey0],
                [Usages::HidUsageKeyDot],
                [Usages::HidUsageKey0],
                [Usages::HidUsageKeyDot],
                [Usages::HidUsageKey1],
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeySemicolon, Usages::HidUsageKeyLeftShift],
                [],
                [Usages::HidUsageKey8],
                [Usages::HidUsageKey0],
                [Usages::HidUsageKey8],
                [Usages::HidUsageKey0],
                [],
            ]
        );
    }

    #[test]
    fn sentence() {
        assert_eq!(
            derive_key_sequence(&keymaps::US_QWERTY, "Hello, world!"),
            reports![
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyH, Usages::HidUsageKeyLeftShift],
                [],
                [Usages::HidUsageKeyE],
                [Usages::HidUsageKeyL],
                [],
                [Usages::HidUsageKeyL],
                [Usages::HidUsageKeyO],
                [Usages::HidUsageKeyComma],
                [Usages::HidUsageKeySpace],
                [Usages::HidUsageKeyW],
                [Usages::HidUsageKeyO],
                [Usages::HidUsageKeyR],
                [Usages::HidUsageKeyL],
                [Usages::HidUsageKeyD],
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKey1, Usages::HidUsageKeyLeftShift],
                [],
            ]
        );
    }

    #[test]
    fn hold_shift() {
        assert_eq!(
            derive_key_sequence(&keymaps::US_QWERTY, "ALL'S WELL!"),
            reports![
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyA, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyL, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyL, Usages::HidUsageKeyLeftShift],
                [],
                [Usages::HidUsageKeyApostrophe],
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyS, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeySpace, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyW, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyE, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyL, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyL, Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKey1, Usages::HidUsageKeyLeftShift],
                [],
            ]
        );
    }

    #[test]
    fn tab_and_newline() {
        assert_eq!(
            derive_key_sequence(&keymaps::US_QWERTY, "\tHello\n"),
            reports![
                [Usages::HidUsageKeyTab],
                [Usages::HidUsageKeyLeftShift],
                [Usages::HidUsageKeyH, Usages::HidUsageKeyLeftShift],
                [],
                [Usages::HidUsageKeyE],
                [Usages::HidUsageKeyL],
                [],
                [Usages::HidUsageKeyL],
                [Usages::HidUsageKeyO],
                [Usages::HidUsageKeyEnter],
                [],
            ]
        );
    }
}