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//! The `observable` module provides the building blocks for creating and manipulating
//! observables, allowing for reactive programming in Rust.
#![allow(clippy::needless_doctest_main)]
mod background_unsubscribe;
pub mod multicast;
use std::{
collections::VecDeque,
error::Error,
sync::{Arc, Mutex},
time::Duration,
};
use crate::{observer::Observer, subscribe::Fuse, subscription::subscribe::UnsubscribeLogic};
use crate::{
subscribe::SubscriptionCollection,
subscription::subscribe::{
Subscribeable, Subscriber, Subscription, SubscriptionHandle, Unsubscribeable,
},
};
use self::{background_unsubscribe::setup_unsubscribe_channel, multicast::Connectable};
enum EmittedValue<T> {
Success(T),
Complete,
Error(Arc<dyn std::error::Error + Send + Sync>),
}
/// Error indicating that an observable sequence is empty.
#[derive(Debug, Clone)]
pub struct EmptyError;
impl std::fmt::Display for EmptyError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "no elements in sequence")
}
}
impl Error for EmptyError {}
type SubscribeFn<T> = Box<dyn FnMut(Subscriber<T>) -> Subscription + Send + Sync>;
type PendingObservables<T> = VecDeque<(Observable<T>, Subscriber<T>)>;
/// The `Observable` struct represents a source of values that can be observed
/// and transformed.
///
/// This struct serves as the foundation for creating, transforming, and working with
/// observables. It provides methods for applying operators, subscribing to emitted
/// values, and creating new observables.
///
/// # Example: basic synchronous `Observable`
///
/// This simple `Observable` emits values and completes. It returns an empty `Subscription`,
/// making it unable to be unsubscribed from. Some operators like `take`, `switch_map`,
/// `merge_map`, `concat_map`, and `exhaust_map` require unsubscribe functionality to
/// work correctly.
///
/// Additionally, this is a synchronous `Observable`, so it blocks the current thread
/// until it completes emission.
///
/// ```no_run
/// use rxr::subscribe::{Subscriber, Subscription, SubscriptionHandle, UnsubscribeLogic};
/// use rxr::{Observable, Observer, Subscribeable};
///
/// // Create a custom observable that emits values from 1 to 10.
/// let mut emit_10_observable = Observable::new(|mut subscriber| {
/// let mut i = 1;
///
/// while i <= 10 {
/// // Emit the value to the subscriber.
/// subscriber.next(i);
/// i += 1;
/// }
/// // Signal completion to the subscriber.
/// subscriber.complete();
///
/// // Return the empty subscription.
/// Subscription::new(UnsubscribeLogic::Nil, SubscriptionHandle::Nil)
/// });
///
/// // Create the `Subscriber` with a mandatory `next` function, and optional
/// // `complete` function. No need for `error` function in this simple example.
/// let mut observer = Subscriber::on_next(|v| println!("Emitted {}", v));
/// observer.on_complete(|| println!("Completed"));
///
/// // This observable blocks until completion since it doesn't use async or
/// // threads. If you comment out the line below, no emissions will occur
/// // because observables are cold.
/// emit_10_observable.subscribe(observer);
///
/// println!("Custom Observable finished emmiting")
/// ```
///
/// # Example: basic asynchronous `Observable`
///
/// Emits values and completes, returning an empty `Subscription`, making it unable
/// to be unsubscribed from. Some operators like `take`, `switch_map`, `merge_map`,
/// `concat_map`, and `exhaust_map` require unsubscribe functionality to work correctly.
///
/// Utilizes an OS thread for asynchronous processing, preventing it from blocking
/// the current thread.
///
/// ```no_run
/// use std::time::Duration;
///
/// use rxr::{
/// subscribe::{Subscriber, Subscription, SubscriptionHandle, UnsubscribeLogic},
/// Observable, ObservableExt, Observer, Subscribeable,
/// };
///
/// // Create a custom observable that emits values from 1 to 10 in separate thread.
/// let observable = Observable::new(|mut o| {
/// // Launch a new thread for the Observable's processing and store its handle.
/// let join_handle = std::thread::spawn(move || {
/// for i in 0..=15 {
/// // Emit the value to the subscriber.
/// o.next(i);
/// // Important. Put an await point after each emit or after some emits.
/// // This allows the `take()` operator to function properly.
/// // Not required in this example.
/// std::thread::sleep(Duration::from_millis(1));
/// }
/// // Signal completion to the subscriber.
/// o.complete();
/// });
///
/// // Return the subscription.
/// Subscription::new(
/// // In this example, we omit the unsubscribe functionality. Without it, we
/// // can't unsubscribe, which prevents the `take()` operator, as well as
/// // higher-order operators like `switch_map`, `merge_map`, `concat_map`,
/// // and `exhaust_map`, from functioning as expected.
/// UnsubscribeLogic::Nil,
/// // Store the `JoinHandle` to enable waiting functionality using the
/// // `Subscription` for this Observable thread to complete.
/// SubscriptionHandle::JoinThread(join_handle),
/// )
/// });
///
/// // Create the `Subscriber` with a mandatory `next` function, and optional
/// // `complete` function. No need for `error` function in this simple example.
/// let mut observer = Subscriber::on_next(|v| println!("Emitted {}", v));
/// observer.on_complete(|| println!("Completed"));
///
/// // This observable uses OS threads so it will not block the current thread.
/// // Observables are cold so if you comment out the statement bellow nothing
/// // will be emitted.
/// let subscription = observable
/// .filter(|&v| v <= 10)
/// .map(|v| format!("Mapped {}", v))
/// .subscribe(observer);
///
/// // Do something else here.
/// println!("Do something while Observable is emitting.");
///
/// // Because the subscription creates a new thread, we can utilize the `Subscription`
/// // to wait for its completion. This ensures that the main thread won't terminate
/// // prematurely and stop all child threads.
/// if subscription.join().is_err() {
/// // Handle error
/// }
///
/// println!("Custom Observable finished emmiting")
/// ```
///
/// # Example: asynchronous `Observable` with `unsubscribe`
///
/// Emits values and completes, returning a `Subscription` that can be unsubscribed
/// from, enabling all operators to function correctly. Utilizes an OS thread for
/// asynchronous processing, preventing it from blocking the current thread.
///
/// ```no_run
/// use std::{
/// sync::{Arc, Mutex},
/// time::Duration,
/// };
///
/// use rxr::{
/// subscribe::{Subscriber, Subscription, SubscriptionHandle, UnsubscribeLogic, Unsubscribeable},
/// Observable, ObservableExt, Observer, Subscribeable,
/// };
///
/// const UNSUBSCRIBE_SIGNAL: bool = true;
///
/// // Create a custom observable that emits values in a separate thread.
/// let observable = Observable::new(|mut o| {
/// let done = Arc::new(Mutex::new(false));
/// let done_c = Arc::clone(&done);
/// let (tx, rx) = std::sync::mpsc::channel();
///
/// // Spawn a new thread to await a signal sent from the unsubscribe logic.
/// std::thread::spawn(move || {
/// // Attempt to receive a signal sent from the unsubscribe logic.
/// if let Ok(UNSUBSCRIBE_SIGNAL) = rx.recv() {
/// // Update the `done_c` mutex with the received signal.
/// *done_c.lock().unwrap() = UNSUBSCRIBE_SIGNAL;
/// }
/// });
///
/// // Launch a new thread for the Observable's processing and store its handle.
/// let join_handle = std::thread::spawn(move || {
/// for i in 0..=10000 {
/// // If an unsubscribe signal is received, exit the loop and stop emissions.
/// if *done.lock().unwrap() == UNSUBSCRIBE_SIGNAL {
/// break;
/// }
/// // Emit the value to the subscriber.
/// o.next(i);
/// // Important. Put an await point after each emit or after some emits.
/// // This allows the `take()` operator to function properly.
/// std::thread::sleep(Duration::from_millis(1));
/// }
/// // Signal completion to the subscriber.
/// o.complete();
/// });
///
/// // Return a new `Subscription` with custom unsubscribe logic.
/// Subscription::new(
/// // The provided closure defines the behavior of the subscription when it
/// // is unsubscribed. In this case, it sends a signal to an asynchronous
/// // observable to stop emitting values.
/// UnsubscribeLogic::Logic(Box::new(move || {
/// if tx.send(UNSUBSCRIBE_SIGNAL).is_err() {
/// println!("Receiver dropped.");
/// }
/// })),
/// // Store the `JoinHandle` for awaiting completion using the `Subscription`.
/// SubscriptionHandle::JoinThread(join_handle),
/// )
/// });
///
/// // Create the `Subscriber` with a mandatory `next` function, and optional
/// // `complete` function. No need for `error` function in this simple example.
/// let mut observer = Subscriber::on_next(|v| println!("Emitted {}", v));
/// observer.on_complete(|| println!("Completed"));
///
/// // This observable uses OS threads so it will not block the current thread.
/// // Observables are cold so if you comment out the statement bellow nothing
/// // will be emitted.
/// let subscription = observable
/// // `take` utilizes our unsubscribe function to stop background emissions
/// // after a specified item count.
/// .take(500)
/// .map(|v| format!("Mapped {}", v))
/// .subscribe(observer);
///
/// // Do something else here.
/// println!("Do something while Observable is emitting.");
///
/// // Unsubscribe from the observable to stop emissions.
/// subscription.unsubscribe();
///
/// // Allow some time for the main thread to confirm that the observable indeed
/// // isn't emitting.
/// std::thread::sleep(Duration::from_millis(2000));
/// println!("`main` function done")
/// ```
///
/// # Example: asynchronous `Observable` with `Tokio`
///
/// Emits values and completes, returning a `Subscription` that can be unsubscribed
/// from, enabling all operators to function correctly. Utilizes `Tokio` tasks for
/// asynchronous processing, preventing it from blocking the current thread.
///
///```no_run
/// use std::sync::{Arc, Mutex};
///
/// use rxr::{
/// subscribe::{Subscriber, Subscription, SubscriptionHandle, UnsubscribeLogic},
/// Observable, ObservableExt, Observer, Subscribeable,
/// };
///
/// use tokio::{task, time, sync::mpsc::channel};
///
/// const UNSUBSCRIBE_SIGNAL: bool = true;
///
/// #[tokio::main()]
/// async fn main() {
/// // Create a custom observable that emits values in a separate task.
/// let observable = Observable::new(|mut o| {
/// let done = Arc::new(Mutex::new(false));
/// let done_c = Arc::clone(&done);
/// let (tx, mut rx) = channel(10);
///
/// // Spawn a new Tokio task to await a signal sent from the unsubscribe logic.
/// task::spawn(async move {
/// // Attempt to receive a signal sent from the unsubscribe logic.
/// if let Some(UNSUBSCRIBE_SIGNAL) = rx.recv().await {
/// // Update the `done_c` mutex with the received signal.
/// *done_c.lock().unwrap() = UNSUBSCRIBE_SIGNAL;
/// }
/// });
///
/// // Launch a new Tokio task for the Observable's processing and store its handle.
/// let join_handle = task::spawn(async move {
/// for i in 0..=10000 {
/// // If an unsubscribe signal is received, exit the loop and stop emissions.
/// if *done.lock().unwrap() == UNSUBSCRIBE_SIGNAL {
/// break;
/// }
/// // Emit the value to the subscriber.
/// o.next(i);
/// // Important. Put an await point after each emit or after some emits.
/// // This allows the `take()` operator to function properly.
/// time::sleep(time::Duration::from_millis(1)).await;
/// }
/// // Signal completion to the subscriber.
/// o.complete();
/// });
///
/// // Return a new `Subscription` with custom unsubscribe logic.
/// Subscription::new(
/// // The provided closure defines the behavior of the subscription when it
/// // is unsubscribed. In this case, it sends a signal to an asynchronous
/// // observable to stop emitting values. If your closure requires Tokio
/// // tasks or channels to send unsubscribe signals, use `UnsubscribeLogic::Future`.
/// UnsubscribeLogic::Future(Box::pin(async move {
/// if tx.send(UNSUBSCRIBE_SIGNAL).await.is_err() {
/// println!("Receiver dropped.");
/// }
/// })),
/// // Store the `JoinHandle` for awaiting completion using the `Subscription`.
/// SubscriptionHandle::JoinTask(join_handle),
/// )
/// });
///
/// // Create the `Subscriber` with a mandatory `next` function, and optional
/// // `complete` function. No need for `error` function in this simple example.
/// let mut observer = Subscriber::on_next(|v| println!("Emitted {}", v));
/// observer.on_complete(|| println!("Completed"));
///
/// // This observable uses Tokio tasks so it will not block the current thread.
/// // Observables are cold so if you comment out the statement bellow nothing
/// // will be emitted.
/// let subscription = observable
/// // `take` utilizes our unsubscribe function to stop background emissions
/// // after a specified item count.
/// .take(15)
/// .map(|v| format!("Mapped {}", v))
/// .delay(1000)
/// .subscribe(observer);
///
/// // Do something else here.
/// println!("Do something while Observable is emitting.");
///
/// // Wait for the subscription to either complete as a Tokio task or join an OS thread.
/// if subscription.join_concurrent().await.is_err() {
/// // Handle error
/// }
///
/// println!("`main` function done")
/// }
///```
///
/// # Example: `Observable` with error handling
///
/// Waits for user input and emits both a value and a completion signal upon success.
/// In case of any errors, it signals them to the attached `Observer`.
///
/// Ensure errors are wrapped in an `Arc` before passing them to the Observer's
/// `error` function.
///
///```no_run
/// use std::{error::Error, fmt::Display, io, sync::Arc};
///
/// use rxr::{subscribe::*, Observable, Observer, Subscribeable};
///
/// #[derive(Debug)]
/// struct MyErr(i32);
///
/// impl Display for MyErr {
/// fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
/// write!(f, "number should be less than 100, you entered {}", self.0)
/// }
/// }
///
/// impl Error for MyErr {}
///
/// // Creates an `Observable<i32>` that processes user input and emits or signals errors.
/// pub fn get_less_than_100() -> Observable<i32> {
/// Observable::new(|mut observer| {
/// let mut input = String::new();
///
/// println!("Please enter an integer (less than 100):");
///
/// if let Err(e) = io::stdin().read_line(&mut input) {
/// // Send input error to the observer.
/// observer.error(Arc::new(e));
/// return Subscription::new(UnsubscribeLogic::Nil, SubscriptionHandle::Nil);
/// }
///
/// match input.trim().parse::<i32>() {
/// Err(e) => {
/// // Send parsing error to the observer.
/// observer.error(Arc::new(e));
/// }
/// Ok(num) if num > 100 => {
/// // Send custom error to the observer.
/// observer.error(Arc::new(MyErr(num)))
/// }
/// Ok(num) => {
/// // Emit the parsed value to the observer.
/// observer.next(num);
/// }
/// }
///
/// // Signal completion if there are no errors.
/// // Note: `complete` does not affect the outcome if `error` was called before it.
/// observer.complete();
///
/// Subscription::new(UnsubscribeLogic::Nil, SubscriptionHandle::Nil)
/// })
/// }
///
/// let observer = Subscriber::new(
/// |input| println!("You entered: {}", input),
/// |e| eprintln!("{}", e),
/// || println!("User input handled"),
/// );
///
/// let mut observable = get_less_than_100();
///
/// observable.subscribe(observer);
///```
#[derive(Clone)]
pub struct Observable<T> {
subscribe_fn: Arc<Mutex<SubscribeFn<T>>>,
fused: bool,
defused: bool,
pub(crate) subject: bool,
}
impl<T> Observable<T> {
/// Creates a new `Observable` with the provided subscribe function.
///
/// This method allows you to define custom behavior for the `Observable` by
/// providing a subscribe function (`sf`), a closure that defines the behavior of
/// the `Observable` when subscribed. When the `Observable` is subscribed to, the
/// `sf` function is invoked to manage the delivery of values to the `Subscriber`.
/// It should also return a `Subscription` that enables unsubscribing and can be
/// used for awaiting `Tokio` tasks or joining OS threads when the `Observable`
/// is asynchronous.
pub fn new(sf: impl FnMut(Subscriber<T>) -> Subscription + Send + Sync + 'static) -> Self {
Observable {
subscribe_fn: Arc::new(Mutex::new(Box::new(sf))),
fused: false,
defused: false,
subject: false,
}
}
/// Creates an empty observable.
///
/// The resulting observable does not emit any values and immediately completes
/// upon subscription. It serves as a placeholder or a base case for some
/// observable operations.
#[must_use]
pub fn empty() -> Self {
Observable {
subscribe_fn: Arc::new(Mutex::new(Box::new(|_| {
Subscription::new(UnsubscribeLogic::Nil, SubscriptionHandle::Nil)
}))),
fused: false,
defused: false,
subject: false,
}
}
/// Fuse the observable, allowing it to complete at most once.
///
/// If `complete()` is called on a fused observable, any subsequent emissions
/// will have no effect. This ensures that the observable is closed after the
/// first completion call.
///
/// By default, observables are not fused, allowing them to emit values even
/// after calling `complete()` and permitting multiple calls to `complete()`.
/// When an observable emits an error, it is considered closed and will no longer
/// emit any further values, regardless of being fused or not.
///
/// # Notes
///
/// `fuse()` does not unsubscribe ongoing emissions from the observable;
/// it simply ignores them after the first `complete()` call, ensuring that no
/// more values are emitted.
#[must_use]
pub fn fuse(mut self) -> Self {
self.fused = true;
self.defused = false;
self
}
/// Defuse the observable, allowing it to complete and emit values after calling
/// `complete()`.
///
/// Observables are defused by default, enabling them to emit values even after
/// completion and allowing multiple calls to `complete()`. Calling `defuse()` is
/// not necessary unless the observable has been previously fused using
/// [`fuse()`](#method.fuse). Once an observable is defused, it can emit values
/// and call `complete()` multiple times on its observers.
///
/// # Notes
///
/// Defusing an observable does not allow it to emit an error after the first
/// error emission. Once an error is emitted, the observable is considered closed
/// and will not emit any further values, regardless of being defused or not.
#[must_use]
pub fn defuse(mut self) -> Self {
self.fused = false;
self.defused = true;
self
}
}
/// The `ObservableExt` trait provides a set of extension methods that can be applied
/// to observables to transform and manipulate their behavior.
///
/// This trait enhances the capabilities of the `Observable` struct by allowing users
/// to chain operators together, creating powerful reactive pipelines.
#[allow(clippy::module_name_repetitions)]
pub trait ObservableExt<T: 'static>: Subscribeable<ObsType = T> {
/// Transforms the items emitted by the observable using a transformation
/// function.
///
/// The transformation function `f` is applied to each item emitted by the
/// observable, and the resulting value is emitted by the resulting observable.
fn map<U, F>(mut self, f: F) -> Observable<U>
where
Self: Sized + Send + Sync + 'static,
F: FnOnce(T) -> U + Copy + Sync + Send + 'static,
U: 'static,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let mut u = Subscriber::new(
move |v| {
let t = f(v);
o_shared.lock().unwrap().next(t);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Filters the items emitted by the observable based on a predicate function.
///
/// Only items for which the predicate function returns `true` will be emitted
/// by the resulting observable.
fn filter<P>(mut self, predicate: P) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
P: (FnOnce(&T) -> bool) + Copy + Sync + Send + 'static,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let mut u = Subscriber::new(
move |v| {
if predicate(&v) {
o_shared.lock().unwrap().next(v);
}
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Skips the first `n` items emitted by the observable and then emits the rest.
///
/// If `n` is greater than or equal to the total number of items, it behaves as
/// if the observable is complete and emits no items.
fn skip(mut self, n: usize) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let mut n = n;
let mut u = Subscriber::new(
move |v| {
if n > 0 {
n -= 1;
return;
}
o_shared.lock().unwrap().next(v);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Delays the emissions from the observable by the specified number of
/// milliseconds.
///
/// The `delay` operator introduces a time delay for emissions from the
/// observable, determined by the specified duration.
fn delay(mut self, num_of_ms: u64) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let mut u = Subscriber::new(
move |v| {
std::thread::sleep(Duration::from_millis(num_of_ms));
o_shared.lock().unwrap().next(v);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Accumulates values emitted by an observable over time, producing an accumulated
/// result based on an accumulator function applied to each emitted value.
///
/// The `scan` operator applies an accumulator function over the values emitted by
/// the source observable. It accumulates values into a single accumulated result,
/// and each new value emitted by the source observable contributes to this
/// accumulation. The accumulated result is emitted by the resulting observable.
/// `seed` is optional. If omitted, the first emitted value is used as the `seed`.
fn scan<U, F>(mut self, acc: F, seed: Option<U>) -> Observable<U>
where
Self: Sized + Send + Sync + 'static,
F: FnOnce(U, T) -> U + Copy + Sync + Send + 'static,
U: From<T> + Clone + Send + Sync + 'static,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
// let acc = Arc::new(Mutex::new(acc));
let mut observable = Observable::new(move |o| {
let state = Arc::new(Mutex::new(seed.clone()));
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let state_cl = Arc::clone(&state);
// let acc_cl = Arc::clone(&acc);
let mut u = Subscriber::new(
move |v: T| {
if let Ok(mut state) = state_cl.lock() {
if state.is_none() {
*state = Some(std::convert::Into::into(v));
} else {
*state = state.as_ref().map(|s| acc(s.clone(), v));
}
o_shared
.lock()
.unwrap()
.next(state.as_ref().unwrap().clone());
}
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
// fn scan_a<F>(mut self, acc: F, seed: Option<T>) -> ScanObservable<T>
// where
// Self: Sized + Send + Sync + 'static,
// F: FnMut(T, T) -> T + Sync + Send + 'static,
// T: Clone + Send,
// {
// let subject = self.is_subject();
// let (fused, defused) = self.get_fused();
// let mut observable = ScanObservable::new(
// move |o| {
// let fused = o.fused;
// let defused = o.defused;
// self.set_fused(fused, defused);
// self.subscribe(o)
// },
// acc,
// seed,
// );
// observable.set_subject_indicator(subject);
// observable.set_fused(fused, defused);
// observable
// }
/// Creates a connectable observable from the source observable.
///
/// This operator converts the source observable into a connectable observable,
/// allowing multiple subscribers to connect to the same source without causing
/// multiple subscriptions to the underlying source.
///
/// The actual emission of values from the source observable will occur only
/// after calling the [`connect()`] method on the resulting `Connectable` instance.
///
/// [`connect()`]: multicast/struct.Connectable.html#method.connect
fn connectable(self) -> Connectable<T>
where
Self: Send + Sync + Sized + 'static,
T: Send + Sync + Clone,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut connectable_observable = Connectable::new(Arc::new(Mutex::new(self)));
connectable_observable.set_subject_indicator(subject);
connectable_observable.set_fused(fused, defused);
connectable_observable
}
/// Emits only the first item emitted by the source observable that satisfies the
/// provided `predicate`, optionally applying a default value if no items match
/// the `predicate`.
///
/// The `predicate` function takes two arguments: the emitted item `T` and the index
/// `usize` of the emission. It should return `true` if the item meets the criteria.
///
/// If a `default_value` is provided and no item satisfies the `predicate`, the
/// observable emits the `default_value` instead. If no default value is provided
/// and no item satisfies the `predicate`, the observable emits an `EmptyError`.
///
/// The `first` operator unsubscribes from the background emissions as soon as it
/// takes the first item that satisfies the `predicate`.
fn first<F>(mut self, predicate: F, default_value: Option<T>) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
F: FnOnce(T, usize) -> bool + Copy + Send + Sync + 'static,
T: Clone + Send + Sync,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let mut default_value = default_value.clone();
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let mut signal_sent = false;
let emitted = Arc::new(Mutex::new(false));
let emitted_cl = Arc::clone(&emitted);
let (tx, rx) = setup_unsubscribe_channel();
let mut index = 0;
let mut u = Subscriber::new(
move |v: T| {
if !signal_sent && predicate(v.clone(), index) {
o_shared.lock().unwrap().next(v);
signal_sent = true;
*emitted.lock().unwrap() = true;
tx.send_unsubscribe_signal();
}
index += 1;
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
if let (Ok(mut observer), Ok(emitted)) = (o_cloned_c.lock(), emitted_cl.lock())
{
if !*emitted {
// Observable did not emitted value.
if let Some(v) = default_value.take() {
// There is a default value.
observer.next(v);
observer.complete();
} else {
// There is no default value.
observer.error(Arc::new(EmptyError));
}
return;
}
// Observable did emitted value.
observer.complete();
}
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
let unsubscriber = self.subscribe(u);
rx.unsubscribe_background_emissions(&self, unsubscriber)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Zips the values emitted by multiple observables into a single observable.
///
/// This method combines the values emitted by multiple observables into a single
/// observable, emitting a vector containing the latest value from each observable
/// in order when all observables have emitted a new value. This method is
/// non-blocking and combines the latest values emitted by observables without
/// waiting for completion. It completes as soon as the first observable in the
/// sequence completes and attempts to unsubscribe all zipped observables. If any
/// observable within the sequence encounters an error, it stops emissions, emits
/// that error, and tries to unsubscribe all observables in the sequence.
#[allow(clippy::too_many_lines)]
fn zip(mut self, observable_inputs: Vec<Observable<T>>) -> Observable<Vec<T>>
where
Self: Clone + Sized + Send + Sync + 'static,
T: Clone + Send,
{
use std::collections::HashMap;
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
use std::task::Poll;
#[allow(clippy::needless_pass_by_value)]
fn unsubscribe_stored_subscriptions(
subscriptions_store: Arc<Mutex<Vec<Subscription>>>,
is_subject: bool,
) {
// To avoid dead-lock, we skip calling `unsubscribe()` if source
// observable is one of the Subject variants.
if is_subject {
if let Ok(mut s) = subscriptions_store.lock() {
s.pop();
}
}
if let Ok(mut s) = subscriptions_store.lock() {
while let Some(u) = s.pop() {
u.unsubscribe();
}
}
}
let is_subject = self.is_subject();
let mut observable_inputs: VecDeque<Observable<T>> = observable_inputs.clone().into();
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let input_len = observable_inputs.len();
let all_emits_collect = Arc::new(Mutex::new(HashMap::with_capacity(input_len)));
let subscriptions_store = Arc::new(Mutex::new(Vec::with_capacity(input_len)));
let subscriptions_store_cl = Arc::clone(&subscriptions_store);
let subscriptions_store_cl2 = Arc::clone(&subscriptions_store);
let subscriptions_store_cl3 = Arc::clone(&subscriptions_store);
let tokio_handle = tokio::runtime::Handle::try_current();
let mut idx = 0;
while let Some(mut input) = observable_inputs.pop_front() {
let inner_emits_collect = VecDeque::with_capacity(16);
all_emits_collect
.lock()
.unwrap()
.insert(idx, inner_emits_collect);
let all_emits_collect_cl = Arc::clone(&all_emits_collect);
let all_emits_collect_cl2 = Arc::clone(&all_emits_collect);
let all_emits_collect_cl3 = Arc::clone(&all_emits_collect);
let inner_subscriber = Subscriber::new(
move |v: T| {
let all_emits_collect_cl = Arc::clone(&all_emits_collect_cl);
if let Some(inner_emits) =
all_emits_collect_cl.lock().unwrap().get_mut(&idx)
{
inner_emits.push_back(EmittedValue::Success(v));
};
},
move |e| {
if let Some(inner_emits) =
all_emits_collect_cl2.lock().unwrap().get_mut(&idx)
{
inner_emits.push_back(EmittedValue::Error(e));
}
},
move || {
if let Some(inner_emits) =
all_emits_collect_cl3.lock().unwrap().get_mut(&idx)
{
inner_emits.push_back(EmittedValue::Complete);
}
},
);
let subscriptions_store = Arc::clone(&subscriptions_store);
let subscription = input.subscribe(inner_subscriber);
subscriptions_store.lock().unwrap().push(subscription);
idx += 1;
}
let mut unsubscribed = false;
let mut u = Subscriber::new(
move |v| {
if unsubscribed {
return;
}
let mut values = Vec::with_capacity(input_len);
values.push(v);
let mut unsub = false;
let mut i = 0;
loop {
std::thread::sleep(Duration::from_millis(1));
if let Some(s) = all_emits_collect.lock().unwrap().get_mut(&i) {
match s.pop_front() {
Some(EmittedValue::Success(e)) => {
values.push(e);
i += 1;
}
Some(EmittedValue::Complete) => {
unsub = true;
break;
}
Some(EmittedValue::Error(e)) => {
unsub = true;
o_shared.lock().unwrap().error(e);
break;
}
None => (),
}
}
if i == input_len {
break;
}
if tokio::runtime::Handle::try_current().is_ok() {
let ftr = std::future::poll_fn(|cx| {
cx.waker().wake_by_ref();
Poll::Ready::<()>(())
});
tokio::task::spawn(async {
ftr.await;
});
}
}
if unsub {
unsubscribe_stored_subscriptions(
subscriptions_store_cl.clone(),
is_subject,
);
unsubscribed = true;
return;
}
o_shared.lock().unwrap().next(values);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
unsubscribe_stored_subscriptions(subscriptions_store_cl2.clone(), is_subject);
},
move || {
// If outer observable completes first notify all inner
// observables to complete.
o_cloned_c.lock().unwrap().complete();
unsubscribe_stored_subscriptions(subscriptions_store_cl3.clone(), is_subject);
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
let mut outer_subscription = self.subscribe(u);
let handle = outer_subscription.subscription_future;
outer_subscription.subscription_future = SubscriptionHandle::Nil;
subscriptions_store.lock().unwrap().push(outer_subscription);
if tokio_handle.is_ok() {
return Subscription::new(
UnsubscribeLogic::Future(Box::pin(async move {
unsubscribe_stored_subscriptions(subscriptions_store, false);
})),
handle,
);
}
Subscription::new(
UnsubscribeLogic::Logic(Box::new(move || {
unsubscribe_stored_subscriptions(subscriptions_store, false);
})),
handle,
)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Emits at most the first `n` items emitted by the observable, then
/// unsubscribes.
///
/// If the observable emits more than `n` items, this operator will only allow
/// the first `n` items to be emitted. After emitting `n` items, it will
/// unsubscribe from the observable.
///
/// # Notes
///
/// For `Subject` variants, using `take(n)` as the initial operator
/// (e.g., `subject.take(n).delay(n)`) will not call unsubscribe and remove
/// registered subscribers for performance reasons.
///
/// However, when used as a non-initial operator (e.g., `subject.delay(n).take(n)`),
/// it will call unsubscribe and remove registered subscribers.
fn take(mut self, n: usize) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut i = 0;
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let (tx, rx) = setup_unsubscribe_channel();
let mut signal_sent = false;
// Alternative implementation for Subject's if desired behavior is to
// skip call to unsubscribe() when take() operator is used. This might be
// used for performance reasons because opening a channel and spawning a
// new thread can be skipped when this operator is used on Subject's.
if self.is_subject() {
signal_sent = true;
}
let mut u = Subscriber::new(
move |v| {
if i < n {
i += 1;
o_shared.lock().unwrap().next(v);
} else if !signal_sent {
signal_sent = true;
tx.send_unsubscribe_signal();
}
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = true;
self.set_fused(fused, defused);
let unsubscriber = self.subscribe(u);
rx.unsubscribe_background_emissions(&self, unsubscriber)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Continuously emits the values from the source observable until an event occurs,
/// triggered by an emitted value from a separate `notifier` observable.
///
/// The `takeUntil` operator subscribes to and starts replicating the behavior of
/// the source observable. Simultaneously, it observes a second observable,
/// referred to as the `notifier`, provided by the user. When the `notifier` emits
/// a value, the resulting observable stops replicating the source observable and
/// completes. If the `notifier` completes without emitting any value, `takeUntil`
/// will pass all values from the source observable. When the `notifier` triggers
/// its first emission `take_until` unsubscribes from ongoing emissions of the
/// source observable.
///
/// The `take_until` operator accepts a second parameter, `unsubscribe_notifier`,
/// allowing control over whether `takeUntil` will attempt to unsubscribe from
/// emissions of the `notifier` observable. When set to `true`, `takeUntil`
/// actively attempts to unsubscribe from the `notifier`'s emissions. When set to
/// `false`, `takeUntil` refrains from attempting to unsubscribe from the
/// `notifier`, allowing the emissions to continue unaffected.
fn take_until<U: 'static>(
mut self,
notifier: Observable<U>,
unsubscribe_notifier: bool,
) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
{
let notifier = Arc::new(Mutex::new(notifier));
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let (tx, rx) = setup_unsubscribe_channel();
let mut signal_sent = false;
let notifier_next_called = Arc::new(Mutex::new(false));
let notifier_next_called_cl = Arc::clone(¬ifier_next_called);
// Make an inner Observer which will set `notifier called` flag.
let observer =
Subscriber::on_next(move |_: U| *notifier_next_called_cl.lock().unwrap() = true);
let notifier = Arc::clone(¬ifier);
let subscription = Arc::new(Mutex::new(None));
let subscription_cl = Arc::clone(&subscription);
// If Tokio is used, subscribe notifier in a Tokio task even if runtime
// flavor is `current_thread`. This is because notifier can start Tokio
// tasks and they can't be started in OS thread. Program would panic instead.
if tx.is_tokio_used() {
tokio::task::spawn(async move {
let subscription = notifier.lock().unwrap().subscribe(observer);
*subscription_cl.lock().unwrap() = Some(subscription);
});
} else {
std::thread::spawn(move || {
let subscription = notifier.lock().unwrap().subscribe(observer);
*subscription_cl.lock().unwrap() = Some(subscription);
});
}
// Alternative implementation for Subject's if desired behavior is to
// skip call to unsubscribe() when take() operator is used. This might be
// used for performance reasons because opening a channel and spawning a
// new thread can be skipped when this operator is used on Subject's.
if self.is_subject() {
signal_sent = true;
}
let mut u = Subscriber::new(
move |v| {
if !(*notifier_next_called.lock().unwrap()) {
o_shared.lock().unwrap().next(v);
} else if !signal_sent {
signal_sent = true;
tx.send_unsubscribe_signal();
if unsubscribe_notifier {
if let Some(s) = subscription.lock().unwrap().take() {
s.unsubscribe();
}
}
} else if unsubscribe_notifier {
if let Some(s) = subscription.lock().unwrap().take() {
s.unsubscribe();
}
}
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = true;
self.set_fused(fused, defused);
let unsubscriber = self.subscribe(u);
rx.unsubscribe_background_emissions(&self, unsubscriber)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Continues emitting values from the source observable as long as each value
/// meets the specified `predicate` criteria. The operation concludes immediately
/// upon encountering the first value that doesn't satisfy the `predicate`.
///
/// Upon subscription, `takeWhile` starts replicating the source observable.
/// Every emitted value from the source is evaluated by the `predicate` function,
/// returning a boolean that represents a condition for the source values. The
/// resulting observable continues emitting source values until the `predicate`
/// yields `false`. When the specified condition is no longer met, `takeWhile`
/// ceases mirroring the source, subsequently unsubscribing from the source to
/// stop background emissions.
fn take_while<P>(mut self, predicate: P) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
P: FnOnce(&T) -> bool + Copy + Sync + Send + 'static,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let (tx, rx) = setup_unsubscribe_channel();
let mut signal_sent = false;
// Alternative implementation for Subject's if desired behavior is to
// skip call to unsubscribe() when take() operator is used. This might be
// used for performance reasons because opening a channel and spawning a
// new thread can be skipped when this operator is used on Subject's.
if self.is_subject() {
signal_sent = true;
}
let mut u = Subscriber::new(
move |v| {
if predicate(&v) {
o_shared.lock().unwrap().next(v);
} else if !signal_sent {
signal_sent = true;
tx.send_unsubscribe_signal();
}
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = true;
self.set_fused(fused, defused);
let unsubscriber = self.subscribe(u);
rx.unsubscribe_background_emissions(&self, unsubscriber)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Produces an observable that emits, at maximum, the final `count` values
/// emitted by the source observable.
///
/// Utilizing `takeLast` creates an observable that retains up to 'count' values
/// in memory until the source observable completes. Upon completion, it delivers
/// all stored values in their original order to the consumer and signals completion.
///
/// In scenarios where the source completes before reaching the specified `count`
/// in `takeLast`, it emits all received values up to that point and then signals completion.
///
/// # Notes
///
/// When applied to an observable that never completes, `takeLast` yields an
/// observable that doesn't emit any value.
fn take_last(mut self, count: usize) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
T: Send,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let last_values_buffer = Arc::new(Mutex::new(VecDeque::with_capacity(count)));
let last_values_buffer_cl = Arc::clone(&last_values_buffer);
let fused = o.fused;
let defused = o.defused;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let i = Arc::new(Mutex::new(0));
let i_cl = Arc::clone(&i);
let mut u = Subscriber::new(
move |v| {
if count == 0 {
return;
}
if let (Ok(mut counter), Ok(mut last_values_buffer)) =
(i.lock(), last_values_buffer_cl.lock())
{
*counter += 1;
if *counter > count {
last_values_buffer.pop_front();
}
last_values_buffer.push_back(v);
}
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
if let (Ok(mut o), Ok(mut last_values_buffer)) =
(o_shared.lock(), last_values_buffer.lock())
{
while let Some(item) = last_values_buffer.pop_front() {
o.next(item);
}
let _ = i_cl.lock().map(|mut counter| *counter = 0);
o.complete();
}
},
);
u.take_wrapped = true;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// The `tap` operator allows you to intercept the items emitted by an observable
/// and perform side effects on those items without modifying the emitted data or
/// the stream itself.
///
/// This operator is used primarily for side effects. It allows you to perform
/// actions or operations on the items emitted by an observable without affecting
/// the stream itself. The `tap` operator is best used for debugging, logging, or
/// performing actions that don't change the emitted values but are necessary for
/// monitoring or debugging purposes such as console logging, data inspection,
/// or triggering some external action based on the emitted values.
///
/// ```text
/// let log_observer = Subscriber::new(
/// |v| println!("Filtered {}", v),
/// |e| println!("Filtered error {}", e),
/// || println!("Filtered complete")
/// );
///
/// observable
/// .tap(Subscriber::on_next(|v| println!("Before filtering: {}", v)))
/// .filter(|v| v % 2 == 0)
/// .tap(log_observer)
/// .subscribe(observer);
/// ```
fn tap(mut self, observer: Subscriber<T>) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
T: Clone,
{
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let observer = Arc::new(Mutex::new(observer));
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let observer = Arc::clone(&observer);
let observer_cl = Arc::clone(&observer);
let observer_e = Arc::clone(&observer);
let mut u = Subscriber::new(
move |v: T| {
if let Ok(mut s) = observer.lock() {
s.next(v.clone());
}
o_shared.lock().unwrap().next(v);
},
move |observable_error| {
if let Ok(mut s) = observer_e.lock() {
s.error(observable_error.clone());
}
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
if let Ok(mut s) = observer_cl.lock() {
s.complete();
}
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Merges the current observable with a vector of observables, emitting items
/// from all of them concurrently.
fn merge(mut self, mut sources: Vec<Observable<T>>) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
{
fn wrap_subscriber<S: 'static>(
s: Arc<Mutex<Subscriber<S>>>,
is_fused: bool,
is_defused: bool,
is_take_wrapped: bool,
) -> Subscriber<S> {
let s_complete = s.clone();
let s_error = s.clone();
let mut s = Subscriber::new(
move |v| {
s.lock().unwrap().next(v);
},
move |e| {
s_error.lock().unwrap().error(e);
},
move || {
s_complete.lock().unwrap().complete();
},
);
s.take_wrapped = is_take_wrapped;
s.set_fused(is_fused, is_defused);
s
}
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let take_wrapped = o.take_wrapped;
let fused = o.fused;
let defused = o.defused;
// o.fused = false;
// o.defused = false;
let o = Arc::new(Mutex::new(o));
let mut subscriptions = Vec::with_capacity(sources.len());
let mut use_tokio_task = false;
self.set_fused(fused, defused);
let s = self.subscribe(wrap_subscriber(o.clone(), fused, defused, take_wrapped));
if let UnsubscribeLogic::Future(_) = &s.unsubscribe_logic {
use_tokio_task = true;
}
for source in &mut sources {
let wrapped = wrap_subscriber(o.clone(), fused, defused, false);
// source.set_fused((fused, defused));
let subscription = source.subscribe(wrapped);
if let UnsubscribeLogic::Future(_) = &subscription.unsubscribe_logic {
use_tokio_task = true;
}
subscriptions.push(subscription);
}
// If Tokio is used with `current_thread` runtime flavor, returned
// Subscriber will be `UnsubscribeLogic::Logic` so that `take()` can
// unsubscribe background emissions in all cases.
if let Ok(handle) = s.runtime_handle.as_ref() {
if let tokio::runtime::RuntimeFlavor::CurrentThread = handle.runtime_flavor() {
use_tokio_task = false;
}
}
subscriptions.push(s);
let subscriptions = Arc::new(Mutex::new(Some(subscriptions)));
let sc = Arc::clone(&subscriptions);
if use_tokio_task {
return Subscription::new(
UnsubscribeLogic::Future(Box::pin(async move {
let subscriptions = subscriptions.lock().unwrap().take();
if let Some(subscriptions) = subscriptions {
for subscription in subscriptions {
subscription.unsubscribe();
}
}
})),
SubscriptionHandle::JoinSubscriptions(SubscriptionCollection::new(sc, true)),
);
}
Subscription::new(
UnsubscribeLogic::Logic(Box::new(move || {
let subscriptions = subscriptions.lock().unwrap().take();
if let Some(subscriptions) = subscriptions {
for subscription in subscriptions {
subscription.unsubscribe();
}
}
})),
SubscriptionHandle::JoinSubscriptions(SubscriptionCollection::new(sc, false)),
)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Merges the current observable with another observable, emitting items from
/// both concurrently.
fn merge_one(mut self, mut source: Observable<T>) -> Observable<T>
where
Self: Sized + Send + Sync + 'static,
{
fn wrap_subscriber<S: 'static>(
s: Arc<Mutex<Subscriber<S>>>,
is_fused: bool,
is_defused: bool,
is_take_wrapped: bool,
) -> Subscriber<S> {
let s_complete = s.clone();
let s_error = s.clone();
let mut s = Subscriber::new(
move |v| {
s.lock().unwrap().next(v);
},
move |e| {
s_error.lock().unwrap().error(e);
},
move || {
s_complete.lock().unwrap().complete();
},
);
s.take_wrapped = is_take_wrapped;
s.set_fused(is_fused, is_defused);
s
}
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let take_wrapped = o.take_wrapped;
let fused = o.fused;
let defused = o.defused;
// o.fused = false;
// o.defused = false;
let o = Arc::new(Mutex::new(o));
let wrapped = wrap_subscriber(o.clone(), fused, defused, take_wrapped);
let wrapped2 = wrap_subscriber(o, fused, defused, false);
let mut use_tokio_task = false;
self.set_fused(fused, defused);
let s1 = self.subscribe(wrapped);
let s2 = source.subscribe(wrapped2);
match (&s1.unsubscribe_logic, &s2.unsubscribe_logic) {
(UnsubscribeLogic::Future(_), _) | (_, UnsubscribeLogic::Future(_)) => {
use_tokio_task = true;
}
_ => (),
}
// If Tokio is used with `current_thread` runtime flavor returned
// Subscriber will be `UnsubscribeLogic::Logic` so that `take()` can
// unsubscribe background emissions in all cases.
if let Ok(handle) = s1.runtime_handle.as_ref() {
if let tokio::runtime::RuntimeFlavor::CurrentThread = handle.runtime_flavor() {
use_tokio_task = false;
}
}
let subscriptions = vec![s1, s2];
let subscriptions = Arc::new(Mutex::new(Some(subscriptions)));
let sc = Arc::clone(&subscriptions);
if use_tokio_task {
return Subscription::new(
UnsubscribeLogic::Future(Box::pin(async move {
let subscriptions = subscriptions.lock().unwrap().take();
if let Some(subscriptions) = subscriptions {
for subscription in subscriptions {
subscription.unsubscribe();
}
}
})),
SubscriptionHandle::JoinSubscriptions(SubscriptionCollection::new(sc, true)),
);
}
Subscription::new(
UnsubscribeLogic::Logic(Box::new(move || {
let subscriptions = subscriptions.lock().unwrap().take();
if let Some(subscriptions) = subscriptions {
for subscription in subscriptions {
subscription.unsubscribe();
}
}
})),
SubscriptionHandle::JoinSubscriptions(SubscriptionCollection::new(sc, false)),
)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Transforms the items emitted by an observable into observables, and flattens
/// the emissions into a single observable, ignoring previous emissions once a
/// new one is encountered. This is similar to `map`, but switches to a new inner
/// observable whenever a new item is emitted.
///
/// # Parameters
/// - `project`: A closure that maps each source item to an observable.
/// The closure returns the observable for each item, and the emissions from
/// these observables are flattened into a single observable.
///
/// # Returns
/// An observable that emits the items from the most recently emitted inner
/// observable.
fn switch_map<R: 'static, F>(mut self, project: F) -> Observable<R>
where
Self: Sized + Send + Sync + 'static,
F: (FnMut(T) -> Observable<R>) + Sync + Send + 'static,
{
let project = Arc::new(Mutex::new(project));
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let project = Arc::clone(&project);
let mut current_subscription: Option<Subscription> = None;
let mut u = Subscriber::new(
move |v| {
let o_shared = Arc::clone(&o_shared);
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let project = Arc::clone(&project);
let mut inner_observable = project.lock().unwrap()(v);
drop(project);
let inner_subscriber = Subscriber::new(
move |k| {
o_shared.lock().unwrap().next(k);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
if let Some(subscription) = current_subscription.take() {
subscription.unsubscribe();
}
let s = inner_observable.subscribe(inner_subscriber);
current_subscription = Some(s);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Transforms the items emitted by the source observable into other observables,
/// and merges them into a single observable stream.
///
/// This operator applies the provided `project` function to each item emitted by
/// the source observable. The function returns another observable. The operator
/// subscribes to these inner observables concurrently and merges their emissions
/// into one observable stream.
///
/// # Parameters
///
/// - `project`: A closure that maps each item emitted by the source observable
/// to another observable.
///
/// # Returns
///
/// An observable that emits items merged from the inner observables produced by
/// the `project` function.
fn merge_map<R: 'static, F>(mut self, project: F) -> Observable<R>
where
Self: Sized + Send + Sync + 'static,
F: (FnMut(T) -> Observable<R>) + Sync + Send + 'static,
{
let project = Arc::new(Mutex::new(project));
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let project = Arc::clone(&project);
let mut u = Subscriber::new(
move |v| {
let o_shared = Arc::clone(&o_shared);
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let project = Arc::clone(&project);
let mut inner_observable = project.lock().unwrap()(v);
drop(project);
let inner_subscriber = Subscriber::new(
move |k| {
o_shared.lock().unwrap().next(k);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
inner_observable.subscribe(inner_subscriber);
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Transforms the items emitted by the source observable into other observables
/// using a closure, and concatenates them into a single observable stream,
/// waiting for each inner observable to complete before moving to the next.
///
/// This operator applies the provided `project` function to each item emitted by
/// the source observable. The function returns another observable. The operator
/// subscribes to these inner observables sequentially and concatenates their
/// emissions into one observable stream.
///
/// # Parameters
///
/// - `project`: A closure that maps each item emitted by the source observable
/// to another observable.
///
/// # Returns
///
/// An observable that emits items concatenated from the inner observables
/// produced by the `project` function.
fn concat_map<R: 'static, F>(mut self, project: F) -> Observable<R>
where
Self: Sized + Send + Sync + 'static,
F: (FnMut(T) -> Observable<R>) + Sync + Send + 'static,
{
let project = Arc::new(Mutex::new(project));
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let project = Arc::clone(&project);
let pending_observables: Arc<Mutex<PendingObservables<R>>> =
Arc::new(Mutex::new(VecDeque::new()));
let mut first_pass = true;
let mut u = Subscriber::new(
move |v| {
let o_shared = Arc::clone(&o_shared);
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let po_cloned = Arc::clone(&pending_observables);
let project = Arc::clone(&project);
let mut inner_observable = project.lock().unwrap()(v);
drop(project);
let inner_subscriber = Subscriber::new(
move |k| o_shared.lock().unwrap().next(k),
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
if let Some((mut io, is)) = po_cloned.lock().unwrap().pop_front() {
io.subscribe(is);
}
},
);
if first_pass {
inner_observable.subscribe(inner_subscriber);
first_pass = false;
return;
}
pending_observables
.lock()
.unwrap()
.push_back((inner_observable, inner_subscriber));
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
/// Maps each item emitted by the source observable to an inner observable using
/// a closure. It subscribes to these inner observables, ignoring new items until
/// the current inner observable completes.
///
/// # Parameters
///
/// - `project`: A closure that maps each item to an inner observable.
///
/// # Returns
///
/// An observable that emits inner observables exclusively. Inner observables do
/// not emit and remain ignored if a preceding inner observable is still emitting.
/// The emission of a subsequent inner observable is allowed only after the
/// current one completes its emission.
fn exhaust_map<R: 'static, F>(mut self, project: F) -> Observable<R>
where
Self: Sized + Send + Sync + 'static,
F: (FnMut(T) -> Observable<R>) + Sync + Send + 'static,
{
let project = Arc::new(Mutex::new(project));
let subject = self.is_subject();
let (fused, defused) = self.get_fused();
let mut observable = Observable::new(move |o| {
let fused = o.fused;
let defused = o.defused;
let take_wrapped = o.take_wrapped;
let o_shared = Arc::new(Mutex::new(o));
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let project = Arc::clone(&project);
let active_subscription = Arc::new(Mutex::new(false));
let guard = Arc::new(Mutex::new(true));
let mut u = Subscriber::new(
move |v| {
let as_cloned = Arc::clone(&active_subscription);
let as_cloned2 = Arc::clone(&active_subscription);
let project = Arc::clone(&project);
let _guard = guard.lock().unwrap();
// Check if previous subscription completed.
let is_previous_subscription_active = *as_cloned.lock().unwrap();
// if hn {
// println!("TRY TO SEND ??????????????????????????????");
// return;
// }
// else {
// println!("SENT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
// *as_cloned.lock().unwrap() = true;
// }
let o_shared = Arc::clone(&o_shared);
let o_cloned_e = Arc::clone(&o_shared);
let o_cloned_c = Arc::clone(&o_shared);
let mut inner_observable = project.lock().unwrap()(v);
drop(project);
let inner_subscriber = Subscriber::new(
move |k| o_shared.lock().unwrap().next(k),
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
// Mark this inner subscription as completed so that next
// one can be allowed to emit all of its values.
*as_cloned2.lock().unwrap() = false;
},
);
// TODO: move this check at the top of the function and return early.
// Do not subscribe current inner subscription if previous one is active.
if !is_previous_subscription_active {
// tokio::task::spawn(async move {
// Mark this inner subscription as active so other following
// subscriptions are rejected until this one completes.
*as_cloned.lock().unwrap() = true;
inner_observable.subscribe(inner_subscriber);
// });
}
},
move |observable_error| {
o_cloned_e.lock().unwrap().error(observable_error);
},
move || {
o_cloned_c.lock().unwrap().complete();
},
);
u.take_wrapped = take_wrapped;
self.set_fused(fused, defused);
self.subscribe(u)
});
observable.set_subject_indicator(subject);
observable.set_fused(fused, defused);
observable
}
}
impl<T> crate::subscription::subscribe::Fuse for Observable<T> {
fn set_fused(&mut self, fused: bool, defused: bool) {
self.fused = fused;
self.defused = defused;
}
fn get_fused(&self) -> (bool, bool) {
(self.fused, self.defused)
}
}
impl<T: 'static> Subscribeable for Observable<T> {
type ObsType = T;
fn subscribe(&mut self, mut v: Subscriber<Self::ObsType>) -> Subscription {
let (fused, defused) = v.get_fused();
if defused || (fused && !self.fused) {
self.defused = v.defused;
self.fused = v.fused;
} else {
v.set_fused(self.fused, self.defused);
}
(self.subscribe_fn.lock().unwrap())(v)
}
fn is_subject(&self) -> bool {
self.subject
}
fn set_subject_indicator(&mut self, s: bool) {
self.subject = s;
}
}
impl<O, T: 'static> ObservableExt<T> for O where O: Subscribeable<ObsType = T> {}
#[cfg(test)]
mod tests;