utils.rs

// Copyright 2019 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use std::sync::Arc;

use anyhow::Context;
use base::error;
use sync::Mutex;
use usb_util::TransferStatus;

use crate::usb::backend::device::BackendDeviceType;
use crate::usb::backend::error::Error;
use crate::usb::backend::error::Result;
use crate::usb::xhci::xhci_transfer::XhciTransferState;
use crate::utils::EventHandler;

#[macro_export]
/// Allows dispatching a function call to all its enum value implementations.
/// See `BackendDeviceType` in usb/backend/device.rs for an example usage of it.
///
/// # Arguments
///
/// * `self` - Replacement for the local `self` reference in the function call.
/// * `enum` - Enum name that the macro is matching on.
/// * `types` - Space-separated list of value types of the given enum.
/// * `func` - Function name that will be called by each match arm.
/// * `param` - Optional parameters needed for the given function call.
macro_rules! multi_dispatch {
    ($self:ident, $enum:ident, $($types:ident )+, $func:ident) => {
        match $self {
            $(
                $enum::$types(device) => device.$func(),
            )+
        }
    };
    ($self:ident, $enum:ident, $($types:ident )+, $func:ident, $param:expr) => {
        match $self {
            $(
                $enum::$types(device) => device.$func($param),
            )+
        }
    };
    ($self:ident, $enum:ident, $($types:ident )+, $func:ident, $param1:expr, $param2: expr) => {
        match $self {
            $(
                $enum::$types(device) => device.$func($param1, $param2),
            )+
        }
    };
    ($self:ident, $enum:ident, $($types:ident )+, $func:ident, $param1:expr, $param2: expr, $param3: expr) => {
        match $self {
            $(
                $enum::$types(device) => device.$func($param1, $param2, $param3),
            )+
        }
    };
}

pub(crate) use multi_dispatch;

pub struct UsbUtilEventHandler {
    pub device: Arc<Mutex<BackendDeviceType>>,
}

impl EventHandler for UsbUtilEventHandler {
    fn on_event(&self) -> anyhow::Result<()> {
        match &mut *self.device.lock() {
            BackendDeviceType::HostDevice(host_device) => host_device
                .device
                .lock()
                .poll_transfers()
                .context("UsbUtilEventHandler poll_transfers failed"),
            BackendDeviceType::FidoDevice(fido_device) => fido_device
                .read_hidraw_file()
                .context("FidoDeviceEventHandler failed to read hidraw device"),
        }
    }
}

/// Helper function to update xhci_transfer state.
pub fn update_transfer_state(state: &mut XhciTransferState, status: TransferStatus) -> Result<()> {
    if status == TransferStatus::Cancelled {
        *state = XhciTransferState::Cancelled;
        return Ok(());
    }

    match *state {
        XhciTransferState::Cancelling => {
            *state = XhciTransferState::Cancelled;
        }
        XhciTransferState::Submitted { .. } => {
            *state = XhciTransferState::Completed;
        }
        _ => {
            error!("xhci trasfer state is invalid");
            *state = XhciTransferState::Completed;
            return Err(Error::BadXhciTransferState);
        }
    }
    Ok(())
}