embassy/embassy-usb/src/lib.rs

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#![no_std]
#![feature(generic_associated_types)]
#![feature(type_alias_impl_trait)]
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// This mod MUST go first, so that the others see its macros.
pub(crate) mod fmt;
mod builder;
pub mod control;
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pub mod descriptor;
mod descriptor_reader;
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pub mod driver;
pub mod types;
use embassy::util::{select, Either};
use heapless::Vec;
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pub use self::builder::{Builder, Config};
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use self::control::*;
use self::descriptor::*;
use self::driver::{Bus, Driver, Event};
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use self::types::*;
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use crate::descriptor_reader::foreach_endpoint;
use crate::driver::ControlPipe;
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/// The global state of the USB device.
///
/// In general class traffic is only possible in the `Configured` state.
#[repr(u8)]
#[derive(PartialEq, Eq, Copy, Clone, Debug)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
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pub enum UsbDeviceState {
/// The USB device is disabled.
Disabled,
/// The USB device has just been enabled or reset.
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Default,
/// The USB device has received an address from the host.
Addressed,
/// The USB device has been configured and is fully functional.
Configured,
}
#[derive(PartialEq, Eq, Copy, Clone, Debug)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum RemoteWakeupError {
InvalidState,
Unsupported,
}
impl From<driver::Unsupported> for RemoteWakeupError {
fn from(_: driver::Unsupported) -> Self {
RemoteWakeupError::Unsupported
}
}
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/// The bConfiguration value for the not configured state.
pub const CONFIGURATION_NONE: u8 = 0;
/// The bConfiguration value for the single configuration supported by this device.
pub const CONFIGURATION_VALUE: u8 = 1;
pub const MAX_INTERFACE_COUNT: usize = 4;
const STRING_INDEX_MANUFACTURER: u8 = 1;
const STRING_INDEX_PRODUCT: u8 = 2;
const STRING_INDEX_SERIAL_NUMBER: u8 = 3;
const STRING_INDEX_CUSTOM_START: u8 = 4;
/// A handler trait for changes in the device state of the [UsbDevice].
pub trait DeviceStateHandler {
/// Called when the USB device has been enabled or disabled.
fn enabled(&self, _enabled: bool) {}
/// Called when the host resets the device.
fn reset(&self) {}
/// Called when the host has set the address of the device to `addr`.
fn addressed(&self, _addr: u8) {}
/// Called when the host has enabled or disabled the configuration of the device.
fn configured(&self, _configured: bool) {}
/// Called when the bus has entered or exited the suspend state.
fn suspended(&self, _suspended: bool) {}
/// Called when remote wakeup feature is enabled or disabled.
fn remote_wakeup_enabled(&self, _enabled: bool) {}
}
struct Interface<'d> {
handler: Option<&'d mut dyn ControlHandler>,
current_alt_setting: u8,
num_alt_settings: u8,
num_strings: u8,
}
pub struct UsbDevice<'d, D: Driver<'d>> {
control_buf: &'d mut [u8],
control: D::ControlPipe,
inner: Inner<'d, D>,
}
struct Inner<'d, D: Driver<'d>> {
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bus: D::Bus,
handler: Option<&'d dyn DeviceStateHandler>,
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config: Config<'d>,
device_descriptor: &'d [u8],
config_descriptor: &'d [u8],
bos_descriptor: &'d [u8],
device_state: UsbDeviceState,
suspended: bool,
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remote_wakeup_enabled: bool,
self_powered: bool,
/// Our device address, or 0 if none.
address: u8,
/// When receiving a set addr control request, we have to apply it AFTER we've
/// finished handling the control request, as the status stage still has to be
/// handled with addr 0.
/// If true, do a set_addr after finishing the current control req.
set_address_pending: bool,
interfaces: Vec<Interface<'d>, MAX_INTERFACE_COUNT>,
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}
impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
pub(crate) fn build(
driver: D,
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config: Config<'d>,
handler: Option<&'d dyn DeviceStateHandler>,
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device_descriptor: &'d [u8],
config_descriptor: &'d [u8],
bos_descriptor: &'d [u8],
interfaces: Vec<Interface<'d>, MAX_INTERFACE_COUNT>,
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control_buf: &'d mut [u8],
) -> UsbDevice<'d, D> {
// Start the USB bus.
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// This prevent further allocation by consuming the driver.
let (bus, control) = driver.start(config.max_packet_size_0 as u16);
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Self {
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control_buf,
control,
inner: Inner {
bus,
config,
handler,
device_descriptor,
config_descriptor,
bos_descriptor,
device_state: UsbDeviceState::Disabled,
suspended: false,
remote_wakeup_enabled: false,
self_powered: false,
address: 0,
set_address_pending: false,
interfaces,
},
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}
}
/// Runs the `UsbDevice` forever.
///
/// This future may leave the bus in an invalid state if it is dropped.
/// After dropping the future, [`UsbDevice::disable()`] should be called
/// before calling any other `UsbDevice` methods to fully reset the
/// peripheral.
pub async fn run(&mut self) -> ! {
loop {
self.run_until_suspend().await;
self.wait_resume().await;
}
}
/// Runs the `UsbDevice` until the bus is suspended.
///
/// This future may leave the bus in an invalid state if it is dropped.
/// After dropping the future, [`UsbDevice::disable()`] should be called
/// before calling any other `UsbDevice` methods to fully reset the
/// peripheral.
pub async fn run_until_suspend(&mut self) -> () {
if self.inner.device_state == UsbDeviceState::Disabled {
self.inner.bus.enable().await;
self.inner.device_state = UsbDeviceState::Default;
if let Some(h) = &self.inner.handler {
h.enabled(true);
}
}
while !self.inner.suspended {
let control_fut = self.control.setup();
let bus_fut = self.inner.bus.poll();
match select(bus_fut, control_fut).await {
Either::First(evt) => self.inner.handle_bus_event(evt),
Either::Second(req) => self.handle_control(req).await,
}
}
}
/// Disables the USB peripheral.
pub async fn disable(&mut self) {
if self.inner.device_state != UsbDeviceState::Disabled {
self.inner.bus.disable().await;
self.inner.device_state = UsbDeviceState::Disabled;
self.inner.suspended = false;
self.inner.remote_wakeup_enabled = false;
if let Some(h) = &self.inner.handler {
h.enabled(false);
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}
}
}
/// Waits for a resume condition on the USB bus.
///
/// This future is cancel-safe.
pub async fn wait_resume(&mut self) {
while self.inner.suspended {
let evt = self.inner.bus.poll().await;
self.inner.handle_bus_event(evt);
}
}
/// Initiates a device remote wakeup on the USB bus.
///
/// If the bus is not suspended or remote wakeup is not enabled, an error
/// will be returned.
///
/// This future may leave the bus in an inconsistent state if dropped.
/// After dropping the future, [`UsbDevice::disable()`] should be called
/// before calling any other `UsbDevice` methods to fully reset the peripheral.
pub async fn remote_wakeup(&mut self) -> Result<(), RemoteWakeupError> {
if self.inner.suspended && self.inner.remote_wakeup_enabled {
self.inner.bus.remote_wakeup().await?;
self.inner.suspended = false;
if let Some(h) = &self.inner.handler {
h.suspended(false);
}
Ok(())
} else {
Err(RemoteWakeupError::InvalidState)
}
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}
async fn handle_control(&mut self, req: [u8; 8]) {
let req = Request::parse(&req);
trace!("control request: {:02x}", req);
match req.direction {
UsbDirection::In => self.handle_control_in(req).await,
UsbDirection::Out => self.handle_control_out(req).await,
}
if self.inner.set_address_pending {
self.inner.bus.set_address(self.inner.address);
self.inner.set_address_pending = false;
}
}
async fn handle_control_in(&mut self, req: Request) {
let mut resp_length = req.length as usize;
let max_packet_size = self.control.max_packet_size();
// If we don't have an address yet, respond with max 1 packet.
// The host doesn't know our EP0 max packet size yet, and might assume
// a full-length packet is a short packet, thinking we're done sending data.
// See https://github.com/hathach/tinyusb/issues/184
const DEVICE_DESCRIPTOR_LEN: usize = 18;
if self.inner.address == 0
&& max_packet_size < DEVICE_DESCRIPTOR_LEN
&& (max_packet_size as usize) < resp_length
{
trace!("received control req while not addressed: capping response to 1 packet.");
resp_length = max_packet_size;
}
match self.inner.handle_control_in(req, &mut self.control_buf) {
InResponse::Accepted(data) => {
let len = data.len().min(resp_length);
let need_zlp = len != resp_length && (len % usize::from(max_packet_size)) == 0;
let chunks = data[0..len]
.chunks(max_packet_size)
.chain(need_zlp.then(|| -> &[u8] { &[] }));
for (first, last, chunk) in first_last(chunks) {
match self.control.data_in(chunk, first, last).await {
Ok(()) => {}
Err(e) => {
warn!("control accept_in failed: {:?}", e);
return;
}
}
}
}
InResponse::Rejected => self.control.reject().await,
}
}
async fn handle_control_out(&mut self, req: Request) {
let req_length = req.length as usize;
let max_packet_size = self.control.max_packet_size();
let mut total = 0;
let chunks = self.control_buf[..req_length].chunks_mut(max_packet_size);
for (first, last, chunk) in first_last(chunks) {
let size = match self.control.data_out(chunk, first, last).await {
Ok(x) => x,
Err(e) => {
warn!("usb: failed to read CONTROL OUT data stage: {:?}", e);
return;
}
};
total += size;
if size < max_packet_size || total == req_length {
break;
}
}
let data = &self.control_buf[0..total];
#[cfg(feature = "defmt")]
trace!(" control out data: {:02x}", data);
#[cfg(not(feature = "defmt"))]
trace!(" control out data: {:02x?}", data);
match self.inner.handle_control_out(req, data) {
OutResponse::Accepted => self.control.accept().await,
OutResponse::Rejected => self.control.reject().await,
}
}
}
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impl<'d, D: Driver<'d>> Inner<'d, D> {
fn handle_bus_event(&mut self, evt: Event) {
match evt {
Event::Reset => {
trace!("usb: reset");
self.device_state = UsbDeviceState::Default;
self.suspended = false;
self.remote_wakeup_enabled = false;
self.address = 0;
for iface in self.interfaces.iter_mut() {
iface.current_alt_setting = 0;
if let Some(h) = &mut iface.handler {
h.reset();
h.set_alternate_setting(0);
}
}
if let Some(h) = &self.handler {
h.reset();
}
}
Event::Resume => {
trace!("usb: resume");
self.suspended = false;
if let Some(h) = &self.handler {
h.suspended(false);
}
}
Event::Suspend => {
trace!("usb: suspend");
self.suspended = true;
if let Some(h) = &self.handler {
h.suspended(true);
}
}
}
}
fn handle_control_out(&mut self, req: Request, data: &[u8]) -> OutResponse {
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const CONFIGURATION_NONE_U16: u16 = CONFIGURATION_NONE as u16;
const CONFIGURATION_VALUE_U16: u16 = CONFIGURATION_VALUE as u16;
match (req.request_type, req.recipient) {
(RequestType::Standard, Recipient::Device) => match (req.request, req.value) {
(Request::CLEAR_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
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self.remote_wakeup_enabled = false;
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if let Some(h) = &self.handler {
h.remote_wakeup_enabled(false);
}
OutResponse::Accepted
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}
(Request::SET_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
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self.remote_wakeup_enabled = true;
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if let Some(h) = &self.handler {
h.remote_wakeup_enabled(true);
}
OutResponse::Accepted
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}
(Request::SET_ADDRESS, addr @ 1..=127) => {
self.address = addr as u8;
self.set_address_pending = true;
self.device_state = UsbDeviceState::Addressed;
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if let Some(h) = &self.handler {
h.addressed(self.address);
}
OutResponse::Accepted
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}
(Request::SET_CONFIGURATION, CONFIGURATION_VALUE_U16) => {
debug!("SET_CONFIGURATION: configured");
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self.device_state = UsbDeviceState::Configured;
// Enable all endpoints of selected alt settings.
foreach_endpoint(self.config_descriptor, |ep| {
let iface = &self.interfaces[ep.interface as usize];
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self.bus
.endpoint_set_enabled(ep.ep_address, iface.current_alt_setting == ep.interface_alt);
})
.unwrap();
// Notify handler.
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if let Some(h) = &self.handler {
h.configured(true);
}
OutResponse::Accepted
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}
(Request::SET_CONFIGURATION, CONFIGURATION_NONE_U16) => match self.device_state {
UsbDeviceState::Default => OutResponse::Accepted,
_ => {
debug!("SET_CONFIGURATION: unconfigured");
self.device_state = UsbDeviceState::Addressed;
// Disable all endpoints.
foreach_endpoint(self.config_descriptor, |ep| {
self.bus.endpoint_set_enabled(ep.ep_address, false);
})
.unwrap();
// Notify handler.
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if let Some(h) = &self.handler {
h.configured(false);
}
OutResponse::Accepted
}
},
_ => OutResponse::Rejected,
},
(RequestType::Standard, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return OutResponse::Rejected,
};
match req.request {
Request::SET_INTERFACE => {
let new_altsetting = req.value as u8;
if new_altsetting >= iface.num_alt_settings {
warn!("SET_INTERFACE: trying to select alt setting out of range.");
return OutResponse::Rejected;
}
iface.current_alt_setting = new_altsetting;
// Enable/disable EPs of this interface as needed.
foreach_endpoint(self.config_descriptor, |ep| {
if ep.interface == req.index as u8 {
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self.bus
.endpoint_set_enabled(ep.ep_address, iface.current_alt_setting == ep.interface_alt);
}
})
.unwrap();
// TODO check it is valid (not out of range)
// TODO actually enable/disable endpoints.
if let Some(handler) = &mut iface.handler {
handler.set_alternate_setting(new_altsetting);
}
OutResponse::Accepted
}
_ => OutResponse::Rejected,
}
}
(RequestType::Standard, Recipient::Endpoint) => match (req.request, req.value) {
(Request::SET_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
let ep_addr = ((req.index as u8) & 0x8f).into();
self.bus.endpoint_set_stalled(ep_addr, true);
OutResponse::Accepted
}
(Request::CLEAR_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
let ep_addr = ((req.index as u8) & 0x8f).into();
self.bus.endpoint_set_stalled(ep_addr, false);
OutResponse::Accepted
}
_ => OutResponse::Rejected,
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},
(RequestType::Class, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return OutResponse::Rejected,
};
match &mut iface.handler {
Some(handler) => handler.control_out(req, data),
None => OutResponse::Rejected,
}
}
_ => OutResponse::Rejected,
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}
}
fn handle_control_in<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
match (req.request_type, req.recipient) {
(RequestType::Standard, Recipient::Device) => match req.request {
Request::GET_STATUS => {
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let mut status: u16 = 0x0000;
if self.self_powered {
status |= 0x0001;
}
if self.remote_wakeup_enabled {
status |= 0x0002;
}
buf[..2].copy_from_slice(&status.to_le_bytes());
InResponse::Accepted(&buf[..2])
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}
Request::GET_DESCRIPTOR => self.handle_get_descriptor(req, buf),
Request::GET_CONFIGURATION => {
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let status = match self.device_state {
UsbDeviceState::Configured => CONFIGURATION_VALUE,
_ => CONFIGURATION_NONE,
};
buf[0] = status;
InResponse::Accepted(&buf[..1])
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}
_ => InResponse::Rejected,
},
(RequestType::Standard, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return InResponse::Rejected,
};
match req.request {
Request::GET_STATUS => {
let status: u16 = 0;
buf[..2].copy_from_slice(&status.to_le_bytes());
InResponse::Accepted(&buf[..2])
}
Request::GET_INTERFACE => {
buf[0] = iface.current_alt_setting;
InResponse::Accepted(&buf[..1])
}
Request::GET_DESCRIPTOR => match &mut iface.handler {
Some(handler) => handler.get_descriptor(req, buf),
None => InResponse::Rejected,
},
_ => InResponse::Rejected,
}
}
(RequestType::Standard, Recipient::Endpoint) => match req.request {
Request::GET_STATUS => {
let ep_addr: EndpointAddress = ((req.index as u8) & 0x8f).into();
let mut status: u16 = 0x0000;
if self.bus.endpoint_is_stalled(ep_addr) {
status |= 0x0001;
}
buf[..2].copy_from_slice(&status.to_le_bytes());
InResponse::Accepted(&buf[..2])
}
_ => InResponse::Rejected,
},
(RequestType::Class, Recipient::Interface) => {
let iface = match self.interfaces.get_mut(req.index as usize) {
Some(iface) => iface,
None => return InResponse::Rejected,
};
match &mut iface.handler {
Some(handler) => handler.control_in(req, buf),
None => InResponse::Rejected,
}
}
_ => InResponse::Rejected,
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}
}
fn handle_get_descriptor<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
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let (dtype, index) = req.descriptor_type_index();
match dtype {
descriptor_type::BOS => InResponse::Accepted(self.bos_descriptor),
descriptor_type::DEVICE => InResponse::Accepted(self.device_descriptor),
descriptor_type::CONFIGURATION => InResponse::Accepted(self.config_descriptor),
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descriptor_type::STRING => {
if index == 0 {
buf[0] = 4; // len
buf[1] = descriptor_type::STRING;
buf[2] = lang_id::ENGLISH_US as u8;
buf[3] = (lang_id::ENGLISH_US >> 8) as u8;
InResponse::Accepted(&buf[..4])
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} else {
let s = match index {
STRING_INDEX_MANUFACTURER => self.config.manufacturer,
STRING_INDEX_PRODUCT => self.config.product,
STRING_INDEX_SERIAL_NUMBER => self.config.serial_number,
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_ => {
// Find out which iface owns this string index.
let mut index_left = index - STRING_INDEX_CUSTOM_START;
let mut the_iface = None;
for iface in &mut self.interfaces {
if index_left < iface.num_strings {
the_iface = Some(iface);
break;
}
index_left -= iface.num_strings;
}
if let Some(iface) = the_iface {
if let Some(handler) = &mut iface.handler {
let index = StringIndex::new(index);
let lang_id = req.index;
handler.get_string(index, lang_id)
} else {
warn!("String requested to an interface with no handler.");
None
}
} else {
warn!("String requested but didn't match to an interface.");
None
}
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}
};
if let Some(s) = s {
if buf.len() < 2 {
panic!("control buffer too small");
}
buf[1] = descriptor_type::STRING;
let mut pos = 2;
for c in s.encode_utf16() {
if pos >= buf.len() {
panic!("control buffer too small");
}
buf[pos..pos + 2].copy_from_slice(&c.to_le_bytes());
pos += 2;
}
buf[0] = pos as u8;
InResponse::Accepted(&buf[..pos])
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} else {
InResponse::Rejected
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}
}
}
_ => InResponse::Rejected,
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}
}
}
fn first_last<T: Iterator>(iter: T) -> impl Iterator<Item = (bool, bool, T::Item)> {
let mut iter = iter.peekable();
let mut first = true;
core::iter::from_fn(move || {
let val = iter.next()?;
let is_first = first;
first = false;
let is_last = iter.peek().is_none();
Some((is_first, is_last, val))
})
}