git-next/crates/cli/src/file_watcher.rs

//
use actix::prelude::*;

use actix::Recipient;
use anyhow::{Context, Result};
use notify::event::ModifyKind;
use notify::Watcher;
use tracing::error;
use tracing::info;

use std::path::PathBuf;
use std::time::Duration;

#[derive(Debug, Message)]
#[rtype(result = "()")]
pub struct FileUpdated;

#[derive(Debug, thiserror::Error)]
pub enum Error {
    #[error("io")]
    Io(#[from] std::io::Error),
}
pub async fn watch_file(path: PathBuf, recipient: Recipient<FileUpdated>) -> Result<()> {
    let (tx, rx) = std::sync::mpsc::channel();

    let mut handler = notify::recommended_watcher(tx).context("file watcher")?;
    handler
        .watch(&path, notify::RecursiveMode::NonRecursive)
        .with_context(|| format!("Watch file: {path:?}"))?;
    info!("Watching: {:?}", path);
    async move {
        loop {
            for result in rx.try_iter() {
                match result {
                    Ok(event) => match event.kind {
                        notify::EventKind::Modify(ModifyKind::Data(_)) => {
                            tracing::info!("File modified");
                            recipient.do_send(FileUpdated);
                            break;
                        }
                        notify::EventKind::Modify(_)
                        | notify::EventKind::Create(_)
                        | notify::EventKind::Remove(_)
                        | notify::EventKind::Any
                        | notify::EventKind::Access(_)
                        | notify::EventKind::Other => { /* do nothing */ }
                    },
                    Err(err) => {
                        error!(?err, "Watching file: {path:?}");
                    }
                }
            }
            actix_rt::time::sleep(Duration::from_millis(1000)).await;
        }
    }
    .await;
    Ok(())
}