tari_common_types 0.8.1

//  Copyright 2019 The Tari Project
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use futures::channel::oneshot::Sender as OneshotSender;
use rand::RngCore;
use std::{collections::HashMap, sync::Arc, time::Instant};
use tokio::sync::RwLock;

pub type RequestKey = u64;

/// Generate a new random request key to uniquely identify a request and its corresponding responses.
pub fn generate_request_key<R>(rng: &mut R) -> RequestKey
where R: RngCore {
    rng.next_u64()
}

/// WaitingRequests is used to keep track of a set of WaitingRequests.
#[allow(clippy::type_complexity)]
pub struct WaitingRequests<T> {
    requests: Arc<RwLock<HashMap<RequestKey, Option<(OneshotSender<T>, Instant)>>>>,
}

impl<T> WaitingRequests<T> {
    /// Create a new set of waiting requests.
    pub fn new() -> Self {
        Self {
            requests: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    /// Insert a new waiting request.
    pub async fn insert(&self, key: RequestKey, reply_tx: OneshotSender<T>) {
        self.requests
            .write()
            .await
            .insert(key, Some((reply_tx, Instant::now())));
    }

    /// Remove the waiting request corresponding to the provided key.
    pub async fn remove(&self, key: RequestKey) -> Option<(OneshotSender<T>, Instant)> {
        self.requests.write().await.remove(&key).unwrap_or(None)
    }
}

impl<T> Clone for WaitingRequests<T> {
    fn clone(&self) -> Self {
        Self {
            requests: self.requests.clone(),
        }
    }
}

impl<T> Default for WaitingRequests<T> {
    fn default() -> Self {
        WaitingRequests::new()
    }
}