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|
use std::{
future::Future,
sync::{Arc, Mutex},
time::Duration,
};
use tokio::sync::broadcast;
const CHANNEL_CAPACITY: usize = 100;
/// Pause background requests if [ApiAvailabilityHandle::reset_inactivity_timer] hasn't been
/// called for this long.
const INACTIVITY_TIME: Duration = Duration::from_secs(3 * 24 * 60 * 60);
#[derive(err_derive::Error, Debug)]
pub enum Error {
/// The [`ApiAvailability`] instance was dropped, or the receiver lagged behind.
#[error(display = "API availability instance was dropped")]
Interrupted(#[error(source)] broadcast::error::RecvError),
}
#[derive(PartialEq, Eq, Clone, Copy, Debug, Default)]
pub struct State {
suspended: bool,
pause_background: bool,
offline: bool,
inactive: bool,
}
impl State {
pub fn is_suspended(&self) -> bool {
self.suspended
}
pub fn is_background_paused(&self) -> bool {
self.offline || self.pause_background || self.suspended || self.inactive
}
pub fn is_offline(&self) -> bool {
self.offline
}
}
pub struct ApiAvailability {
state: Arc<Mutex<State>>,
tx: broadcast::Sender<State>,
inactivity_timer: Arc<Mutex<Option<tokio::task::JoinHandle<()>>>>,
}
impl ApiAvailability {
pub fn new(initial_state: State) -> Self {
let (tx, _rx) = broadcast::channel(CHANNEL_CAPACITY);
let state = Arc::new(Mutex::new(initial_state));
let availability = ApiAvailability {
state,
tx,
inactivity_timer: Arc::new(Mutex::new(None)),
};
availability.handle().reset_inactivity_timer();
availability
}
pub fn get_state(&self) -> State {
*self.state.lock().unwrap()
}
pub fn handle(&self) -> ApiAvailabilityHandle {
ApiAvailabilityHandle {
state: self.state.clone(),
tx: self.tx.clone(),
inactivity_timer: self.inactivity_timer.clone(),
}
}
}
impl Drop for ApiAvailability {
fn drop(&mut self) {
if let Some(timer) = self.inactivity_timer.lock().unwrap().take() {
timer.abort();
}
}
}
#[derive(Clone, Debug)]
pub struct ApiAvailabilityHandle {
state: Arc<Mutex<State>>,
tx: broadcast::Sender<State>,
inactivity_timer: Arc<Mutex<Option<tokio::task::JoinHandle<()>>>>,
}
impl ApiAvailabilityHandle {
/// Reset task that automatically pauses API requests due inactivity,
/// starting it if it's not currently running.
pub fn reset_inactivity_timer(&self) {
log::trace!("Restarting API inactivity check");
let self_ = self.clone();
let mut inactivity_timer = self.inactivity_timer.lock().unwrap();
if let Some(timer) = inactivity_timer.take() {
timer.abort();
}
self.set_active();
*inactivity_timer = Some(tokio::spawn(async move {
talpid_time::sleep(INACTIVITY_TIME).await;
self_.set_inactive();
}));
}
/// Stops timer that pauses API requests due to inactivity.
pub fn stop_inactivity_timer(&self) {
log::trace!("Stopping API inactivity check");
let mut inactivity_timer = self.inactivity_timer.lock().unwrap();
if let Some(timer) = inactivity_timer.take() {
timer.abort();
}
self.set_active();
}
fn inactivity_timer_running(&self) -> bool {
self.inactivity_timer.lock().unwrap().is_some()
}
pub fn suspend(&self) {
let mut state = self.state.lock().unwrap();
if !state.suspended {
log::debug!("Suspending API requests");
state.suspended = true;
let _ = self.tx.send(*state);
}
}
pub fn unsuspend(&self) {
let mut state = self.state.lock().unwrap();
if state.suspended {
log::debug!("Unsuspending API requests");
state.suspended = false;
let _ = self.tx.send(*state);
}
}
pub fn pause_background(&self) {
let mut state = self.state.lock().unwrap();
if !state.pause_background {
log::debug!("Pausing background API requests");
state.pause_background = true;
let _ = self.tx.send(*state);
}
}
pub fn resume_background(&self) {
if self.inactivity_timer_running() {
self.reset_inactivity_timer();
}
let mut state = self.state.lock().unwrap();
if state.pause_background {
log::debug!("Resuming background API requests");
state.pause_background = false;
let _ = self.tx.send(*state);
}
}
fn set_inactive(&self) {
let mut state = self.state.lock().unwrap();
if !state.inactive {
log::debug!("Pausing background API requests due to inactivity");
state.inactive = true;
let _ = self.tx.send(*state);
}
}
fn set_active(&self) {
let mut state = self.state.lock().unwrap();
if state.inactive {
log::debug!("Resuming background API requests due to activity");
state.inactive = false;
let _ = self.tx.send(*state);
}
}
pub fn set_offline(&self, offline: bool) {
let mut state = self.state.lock().unwrap();
if state.offline != offline {
if offline {
log::debug!("Pausing API requests due to being offline");
} else {
log::debug!("Resuming API requests due to coming online");
}
state.offline = offline;
let _ = self.tx.send(*state);
}
}
pub fn get_state(&self) -> State {
*self.state.lock().unwrap()
}
pub fn wait_for_unsuspend(&self) -> impl Future<Output = Result<(), Error>> {
self.wait_for_state(|state| !state.is_suspended())
}
pub fn when_bg_resumes<F: Future<Output = O>, O>(&self, task: F) -> impl Future<Output = O> {
let wait_task = self.wait_for_state(|state| !state.is_background_paused());
async move {
let _ = wait_task.await;
task.await
}
}
pub fn wait_background(&self) -> impl Future<Output = Result<(), Error>> {
self.wait_for_state(|state| !state.is_background_paused())
}
pub fn when_online<F: Future<Output = O>, O>(&self, task: F) -> impl Future<Output = O> {
let wait_task = self.wait_for_state(|state| !state.is_offline());
async move {
let _ = wait_task.await;
task.await
}
}
pub fn wait_online(&self) -> impl Future<Output = Result<(), Error>> {
self.wait_for_state(|state| !state.is_offline())
}
fn wait_for_state(
&self,
state_ready: impl Fn(State) -> bool,
) -> impl Future<Output = Result<(), Error>> {
let mut rx = self.tx.subscribe();
let state = self.state.clone();
async move {
let current_state = { *state.lock().unwrap() };
if state_ready(current_state) {
return Ok(());
}
loop {
let new_state = rx.recv().await?;
if state_ready(new_state) {
return Ok(());
}
}
}
}
}
|
