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use std::time::Duration;
use web_time::Instant;
use crate::runtime::Timer;
use crate::runtime::dev::prelude::*;
/// Output the same message periodically.
#[derive(Block)]
#[message_outputs(out)]
pub struct MessageSource {
message: Pmt,
interval: Duration,
t_last: Instant,
n_messages: Option<usize>,
}
impl MessageSource {
/// Create MessageSource block
pub fn new(message: Pmt, interval: Duration, n_messages: Option<usize>) -> Self {
Self {
message,
interval,
t_last: Instant::now(),
n_messages,
}
}
async fn sleep(dur: Duration) {
Timer::after(dur).await;
}
}
#[doc(hidden)]
impl Kernel for MessageSource {
async fn work(
&mut self,
io: &mut WorkIo,
mo: &mut MessageOutputs,
_b: &mut BlockMeta,
) -> Result<()> {
let now = Instant::now();
if now >= self.t_last + self.interval {
mo.post("out", self.message.clone()).await?;
self.t_last = now;
if let Some(ref mut n) = self.n_messages {
*n -= 1;
if *n == 0 {
io.finished = true;
}
}
}
io.block_on(MessageSource::sleep(
self.t_last + self.interval - Instant::now(),
));
Ok(())
}
async fn init(&mut self, _mo: &mut MessageOutputs, _b: &mut BlockMeta) -> Result<()> {
self.t_last = Instant::now();
Ok(())
}
}
/// Repeats a fixed message on an interval
///
/// # Message Inputs
///
/// No message inputs.
///
/// # Message Outputs
///
/// `out`: Repeated message output.
///
/// # Usage
/// ```
/// use std::time;
/// use futuresdr::blocks::MessageSourceBuilder;
/// use futuresdr::runtime::{Flowgraph, Pmt};
///
/// let mut fg = Flowgraph::new();
///
/// // Repeat the message "foo" every 100ms twenty times
/// let msg_source = fg.add(
/// MessageSourceBuilder::new(
/// Pmt::String("foo".to_string()),
/// time::Duration::from_millis(100),
/// )
/// .n_messages(20)
/// .build()
/// );
/// ```
pub struct MessageSourceBuilder {
message: Pmt,
duration: Duration,
n_messages: Option<usize>,
}
impl MessageSourceBuilder {
/// Create MessageSource builder
pub fn new(message: Pmt, duration: Duration) -> MessageSourceBuilder {
MessageSourceBuilder {
message,
duration,
n_messages: None,
}
}
/// Number of message to send
#[must_use]
pub fn n_messages(mut self, n: usize) -> MessageSourceBuilder {
self.n_messages = Some(n);
self
}
/// Build Message Source block
pub fn build(self) -> MessageSource {
MessageSource::new(self.message, self.duration, self.n_messages)
}
}