ed_journals/modules/shared/blocking/
live_json_file_watcher.rsuse std::marker::PhantomData;
use std::path::{Path, PathBuf};
use std::{fs, io};
use notify::{RecommendedWatcher, RecursiveMode, Watcher};
use serde::Deserialize;
use thiserror::Error;
use crate::modules::shared::blocking::sync_blocker::SyncBlocker;
#[derive(Debug)]
pub struct LiveJsonFileWatcher<T>
where
T: for<'de> Deserialize<'de>,
{
blocker: SyncBlocker,
path: PathBuf,
_watcher: RecommendedWatcher,
first: bool,
phantom_data: PhantomData<T>,
}
#[derive(Debug, Error)]
pub enum LiveJsonFileWatcherError {
#[error(transparent)]
NotifyError(#[from] notify::Error),
#[error(transparent)]
IO(#[from] io::Error),
#[error(transparent)]
SerdeJson(#[from] serde_json::Error),
}
impl<T> LiveJsonFileWatcher<T>
where
T: for<'de> Deserialize<'de>,
{
pub fn open<P: AsRef<Path>>(path: P) -> Result<Self, LiveJsonFileWatcherError> {
let blocker = SyncBlocker::new();
let local_blocker = blocker.clone();
let mut watcher = notify::recommended_watcher(move |_| {
local_blocker.unblock();
})?;
watcher.watch(path.as_ref(), RecursiveMode::NonRecursive)?;
Ok(LiveJsonFileWatcher {
blocker,
path: path.as_ref().to_path_buf(),
_watcher: watcher,
first: true,
phantom_data: PhantomData,
})
}
}
impl<T> Iterator for LiveJsonFileWatcher<T>
where
T: for<'de> Deserialize<'de>,
{
type Item = Result<T, LiveJsonFileWatcherError>;
fn next(&mut self) -> Option<Self::Item> {
if !self.first {
self.blocker.block();
}
self.first = false;
let string_content = match fs::read_to_string(&self.path) {
Ok(value) => value,
Err(error) => return Some(Err(error.into())),
};
let value = match serde_json::from_str(&string_content) {
Ok(value) => value,
Err(error) => return Some(Err(error.into())),
};
Some(Ok(value))
}
}