threaded watcher creation and arg for config

new argument `polling` allows to force watcher to use polling instead of file system events.
this should address the issue in #1436 and maybe even #1437

Author: extrawurst

src/args.rs

@@ -2,8 +2,8 @@ use crate::bug_report;
 use anyhow::{anyhow, Result};
 use asyncgit::sync::RepoPath;
 use clap::{
-	crate_authors, crate_description, crate_name, crate_version, Arg,
-	Command as ClapApp,
+	crate_authors, crate_description, crate_name, crate_version,
+	value_parser, Arg, Command as ClapApp,
 };
 use simplelog::{Config, LevelFilter, WriteLogger};
 use std::{
@@ -15,6 +15,7 @@ use std::{
 pub struct CliArgs {
 	pub theme: PathBuf,
 	pub repo_path: RepoPath,
+	pub poll_watcher: bool,
 }
 
 pub fn process_cmdline() -> Result<CliArgs> {
@@ -46,17 +47,20 @@ pub fn process_cmdline() -> Result<CliArgs> {
 		.get_one::<String>("theme")
 		.map_or_else(|| PathBuf::from("theme.ron"), PathBuf::from);
 
-	if get_app_config_path()?.join(&arg_theme).is_file() {
-		Ok(CliArgs {
-			theme: get_app_config_path()?.join(arg_theme),
-			repo_path,
-		})
+	let theme = if get_app_config_path()?.join(&arg_theme).is_file() {
+		get_app_config_path()?.join(arg_theme)
 	} else {
-		Ok(CliArgs {
-			theme: get_app_config_path()?.join("theme.ron"),
-			repo_path,
-		})
-	}
+		get_app_config_path()?.join("theme.ron")
+	};
+
+	let arg_poll: bool =
+		*arg_matches.get_one("poll").unwrap_or(&false);
+
+	Ok(CliArgs {
+		theme,
+		poll_watcher: arg_poll,
+		repo_path,
+	})
 }
 
 fn app() -> ClapApp {
@@ -90,6 +94,13 @@ fn app() -> ClapApp {
 				.long("logging")
 				.num_args(0),
 		)
+		.arg(
+			Arg::new("poll")
+				.help("Poll folder for changes instead of using file system events. This can be useful if you run into issues with maximum # of file descriptors")
+				.long("polling")
+				.num_args(0)
+				.value_parser(value_parser!(bool)),
+		)
 		.arg(
 			Arg::new("bugreport")
 				.help("Generate a bug report")

src/main.rs

@@ -150,6 +150,7 @@ fn main() -> Result<()> {
 			theme,
 			key_config.clone(),
 			&input,
+			cliargs.poll_watcher,
 			&mut terminal,
 		)?;
 
@@ -170,13 +171,17 @@ fn run_app(
 	theme: Theme,
 	key_config: KeyConfig,
 	input: &Input,
+	poll_watcher: bool,
 	terminal: &mut Terminal<CrosstermBackend<io::Stdout>>,
 ) -> Result<QuitState, anyhow::Error> {
 	let (tx_git, rx_git) = unbounded();
 	let (tx_app, rx_app) = unbounded();
 
 	let rx_input = input.receiver();
-	let watcher = RepoWatcher::new(repo_work_dir(&repo)?.as_str())?;
+	let watcher = RepoWatcher::new(
+		repo_work_dir(&repo)?.as_str(),
+		poll_watcher,
+	);
 	let rx_watcher = watcher.receiver();
 	let spinner_ticker = tick(SPINNER_INTERVAL);
 

src/watcher.rs

@@ -1,8 +1,11 @@
 use anyhow::Result;
 use crossbeam_channel::{unbounded, Sender};
-use notify::{Error, RecommendedWatcher, RecursiveMode};
+use notify::{
+	Config, Error, PollWatcher, RecommendedWatcher, RecursiveMode,
+	Watcher,
+};
 use notify_debouncer_mini::{
-	new_debouncer, DebouncedEvent, Debouncer,
+	new_debouncer, new_debouncer_opt, DebouncedEvent,
 };
 use scopetime::scope_time;
 use std::{
@@ -11,22 +14,23 @@ use std::{
 
 pub struct RepoWatcher {
 	receiver: crossbeam_channel::Receiver<()>,
-	#[allow(dead_code)]
-	debouncer: Debouncer<RecommendedWatcher>,
 }
 
 impl RepoWatcher {
-	pub fn new(workdir: &str) -> Result<Self> {
-		scope_time!("RepoWatcher::new");
+	pub fn new(workdir: &str, poll: bool) -> Self {
+		log::trace!(
+			"poll watcher: {poll} recommended: {:?}",
+			RecommendedWatcher::kind()
+		);
 
 		let (tx, rx) = std::sync::mpsc::channel();
 
-		let mut debouncer =
-			new_debouncer(Duration::from_secs(2), None, tx)?;
+		let workdir = workdir.to_string();
 
-		debouncer
-			.watcher()
-			.watch(Path::new(workdir), RecursiveMode::Recursive)?;
+		thread::spawn(move || {
+			let timeout = Duration::from_secs(2);
+			create_watcher(poll, timeout, tx, &workdir);
+		});
 
 		let (out_tx, out_rx) = unbounded();
 
@@ -37,10 +41,7 @@ impl RepoWatcher {
 			}
 		});
 
-		Ok(Self {
-			debouncer,
-			receiver: out_rx,
-		})
+		Self { receiver: out_rx }
 	}
 
 	///
@@ -71,3 +72,38 @@ impl RepoWatcher {
 		}
 	}
 }
+
+fn create_watcher(
+	poll: bool,
+	timeout: Duration,
+	tx: std::sync::mpsc::Sender<
+		Result<Vec<DebouncedEvent>, Vec<Error>>,
+	>,
+	workdir: &str,
+) {
+	scope_time!("create_watcher");
+
+	if poll {
+		let config = Config::default()
+			.with_poll_interval(Duration::from_secs(2));
+		let mut bouncer = new_debouncer_opt::<_, PollWatcher>(
+			timeout, None, tx, config,
+		)
+		.expect("Watch create error");
+		bouncer
+			.watcher()
+			.watch(Path::new(&workdir), RecursiveMode::Recursive)
+			.expect("Watch error");
+
+		std::mem::forget(bouncer);
+	} else {
+		let mut bouncer = new_debouncer(timeout, None, tx)
+			.expect("Watch create error");
+		bouncer
+			.watcher()
+			.watch(Path::new(&workdir), RecursiveMode::Recursive)
+			.expect("Watch error");
+
+		std::mem::forget(bouncer);
+	};
+}