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 MAX_DEVICE_REPORT_COUNT uint32 = 50;

/// The InputReport field to be populated by InputDevice.GetInputReport.
type DeviceType = flexible enum {
    MOUSE = 0;
    SENSOR = 1;
    TOUCH = 2;
    KEYBOARD = 3;
    CONSUMER_CONTROL = 4;
};

/// Each `InputReportsReader` has its own FIFO of InputReports that it maintains.
/// When ReadInputReports is called it drains the InputReports FIFO.
/// If too many InputReports are created before the FIFO is drained, then
/// the oldest InputReport will be silently discarded.
protocol InputReportsReader {
    /// This is a Hanging-Get function to read the reports in the
    /// InputReport FIFO. This will not reply until there is at least one
    /// report available.
    /// If there is already one outstanding Hanging-Get, calling this
    /// again will return ZX_ERR_ALREADY_BOUND.
    ReadInputReports() -> (struct {
        reports vector<InputReport>:MAX_DEVICE_REPORT_COUNT;
    }) error zx.status;
};

/// 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.
@discoverable
protocol InputDevice {
    /// Open a new InputReportsReader on this device. Each reader receives
    /// their own reports.
    GetInputReportsReader(resource struct {
        reader server_end:InputReportsReader;
    });

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

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

    /// Get the feature report for a given device. This requests the state of
    /// the device's features.
    GetFeatureReport() -> (struct {
        report FeatureReport;
    }) error zx.status;

    /// Set the feature report for a given device. This sets the state of
    /// the device's features.
    SetFeatureReport(struct {
        report FeatureReport;
    }) -> (struct {}) error zx.status;

    /// For general cases, InputReportReader is the preferred way of getting
    /// InputReports. For devices that don't send InputReports naturally, this
    /// method can be used to request a report from the device type indicated.
    /// Does not block, and returns ZX_ERR_NOT_SUPPORTED if `GetInputReport` or
    /// `device_type` are not supported.
    GetInputReport(struct {
        device_type DeviceType;
    }) -> (struct {
        report InputReport;
    }) error zx.status;
};