sdk/fidl/fuchsia.input.report/device.fidl

// Copyright 2019 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.

library fuchsia.input.report;

using zx;

const uint32 MAX_DEVICE_REPORT_COUNT = 50;

/// An `InputDevice` driver represents a single physical input device.
/// The InputDevice maintains an internal FIFO of `MAX_DEVICE_REPORT_COUNT`
/// reports for each client that connects. Reports are removed from the FIFO
/// once they are read by the client. If the FIFO is full, it will drop the
/// oldest report to make room for an incoming report.
protocol InputDevice {
    /// Receive an event that will be signalled when there are reports in the
    /// Device's report FIFO. When there are events in the FIFO, `event` will have
    /// `DEV_STATE_READABLE` triggered. When the client has read all of the events,
    /// `DEV_STATE_READABLE` will be  cleared.
    GetReportsEvent() -> (zx.status status, handle<event> event);

    /// Get all of the reports that have been seen since the last time this method was called.
    /// If this returns 0 reports, please wait on the report event.
    GetReports() -> (vector<InputReport>:MAX_DEVICE_REPORT_COUNT reports);

    /// Gets the device descriptor for this device.
    GetDescriptor() -> (DeviceDescriptor descriptor);

    /// Send a single output report to the device. This will throw an error
    /// if the output report does not follow the OutputDescriptor.
    SendOutputReport(OutputReport report) -> () error zx.status;
};