From e51392fcdeae86b08595a3aa9f0b0522fa684215 Mon Sep 17 00:00:00 2001
From: Chip Senkbeil <chip@senkbeil.org>
Date: Mon, 6 Jun 2022 18:47:59 -0500
Subject: [PATCH] Simplify watch event passing by dropping events rather than
 blocking the hot code path

---
 distant-core/src/constants.rs              |  3 --
 distant-core/src/server/distant/handler.rs | 36 ++++++++--------------
 2 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/distant-core/src/constants.rs b/distant-core/src/constants.rs
index e67ecd6..8aa3683 100644
--- a/distant-core/src/constants.rs
+++ b/distant-core/src/constants.rs
@@ -10,9 +10,6 @@ pub const CLIENT_WATCHER_CAPACITY: usize = 100;
 /// Capacity associated with the server's file watcher to pass events outbound
 pub const SERVER_WATCHER_CAPACITY: usize = 10000;
 
-/// Duration in milliseconds to sleep when reaching maximum watcher events in queue
-pub const SERVER_WATCHER_PAUSE_MILLIS: u64 = 100;
-
 /// Represents the maximum size (in bytes) that data will be read from pipes
 /// per individual `read` call
 ///
diff --git a/distant-core/src/server/distant/handler.rs b/distant-core/src/server/distant/handler.rs
index ccf94e4..b2bb836 100644
--- a/distant-core/src/server/distant/handler.rs
+++ b/distant-core/src/server/distant/handler.rs
@@ -1,5 +1,5 @@
 use crate::{
-    constants::{SERVER_WATCHER_CAPACITY, SERVER_WATCHER_PAUSE_MILLIS},
+    constants::SERVER_WATCHER_CAPACITY,
     data::{
         self, Change, ChangeKind, ChangeKindSet, DirEntry, FileType, Metadata, PtySize, Request,
         RequestData, Response, ResponseData, RunningProcess, SystemInfo,
@@ -19,7 +19,7 @@ use std::{
     path::{Path, PathBuf},
     pin::Pin,
     sync::Arc,
-    time::{Duration, SystemTime},
+    time::SystemTime,
 };
 use tokio::{
     io::{self, AsyncWriteExt},
@@ -406,28 +406,16 @@ where
         //       with a large volume of watch requests
         let (tx, mut rx) = mpsc::channel(SERVER_WATCHER_CAPACITY);
 
-        let mut watcher = notify::recommended_watcher(move |res| {
-            let mut res = res;
-
-            // Attempt to send our result, breaking out of the loop
-            // if we succeed or it is impossible, otherwise trying
-            // again after a brief sleep
-            loop {
-                match tx.try_send(res) {
-                    Ok(_) => break,
-                    Err(TrySendError::Full(x)) => {
-                        warn!(
-                            "Reached watcher capacity of {}! Trying again after {}ms",
-                            SERVER_WATCHER_CAPACITY, SERVER_WATCHER_PAUSE_MILLIS
-                        );
-                        res = x;
-                        std::thread::sleep(Duration::from_millis(SERVER_WATCHER_PAUSE_MILLIS));
-                    }
-                    Err(TrySendError::Closed(_)) => {
-                        warn!("Skipping watch event because watcher channel closed");
-                        break;
-                    }
-                }
+        let mut watcher = notify::recommended_watcher(move |res| match tx.try_send(res) {
+            Ok(_) => {}
+            Err(TrySendError::Full(_)) => {
+                warn!(
+                    "Reached watcher capacity of {}! Dropping watcher event!",
+                    SERVER_WATCHER_CAPACITY,
+                );
+            }
+            Err(TrySendError::Closed(_)) => {
+                warn!("Skipping watch event because watcher channel closed");
             }
         })?;