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|
use std::{
future::Future,
sync::{Arc, Mutex},
};
use tokio::sync::broadcast;
const CHANNEL_CAPACITY: usize = 100;
#[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,
}
impl State {
pub fn is_suspended(&self) -> bool {
self.suspended
}
pub fn is_background_paused(&self) -> bool {
self.offline || self.pause_background || self.suspended
}
pub fn is_offline(&self) -> bool {
self.offline
}
}
pub struct ApiAvailability {
state: Arc<Mutex<State>>,
tx: broadcast::Sender<State>,
}
impl ApiAvailability {
pub fn new(initial_state: State) -> Self {
let (tx, _rx) = broadcast::channel(CHANNEL_CAPACITY);
let state = Arc::new(Mutex::new(initial_state));
ApiAvailability { state, tx }
}
pub fn get_state(&self) -> State {
*self.state.lock().unwrap()
}
pub fn handle(&self) -> ApiAvailabilityHandle {
ApiAvailabilityHandle {
state: self.state.clone(),
tx: self.tx.clone(),
}
}
}
#[derive(Clone, Debug)]
pub struct ApiAvailabilityHandle {
state: Arc<Mutex<State>>,
tx: broadcast::Sender<State>,
}
impl ApiAvailabilityHandle {
pub fn suspend(&self) {
log::debug!("Suspending API requests");
let mut state = self.state.lock().unwrap();
if !state.suspended {
state.suspended = true;
let _ = self.tx.send(*state);
}
}
pub fn unsuspend(&self) {
log::debug!("Unsuspending API requests");
let mut state = self.state.lock().unwrap();
if state.suspended {
state.suspended = false;
let _ = self.tx.send(*state);
}
}
pub fn pause_background(&self) {
log::debug!("Pausing background API requests");
let mut state = self.state.lock().unwrap();
if !state.pause_background {
state.pause_background = true;
let _ = self.tx.send(*state);
}
}
pub fn resume_background(&self) {
log::debug!("Resuming background API requests");
let mut state = self.state.lock().unwrap();
if state.pause_background {
state.pause_background = false;
let _ = self.tx.send(*state);
}
}
pub fn set_offline(&self, offline: bool) {
if offline {
log::debug!("Pausing API requests due to being offline");
} else {
log::debug!("Resuming API requests due to coming online");
}
let mut state = self.state.lock().unwrap();
if state.offline != offline {
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(());
}
}
}
}
}
|
