Switch from std::sync::mpsc to crossbeam-channel

Cargo.toml

@@ -51,6 +51,7 @@ dirs-next = "2.0"
 normpath = "0.3.2"
 chrono = "0.4"
 once_cell = "1.15.0"
+crossbeam-channel = "0.5.6"
 
 [dependencies.clap]
 version = "3.1"

src/exec/job.rs

@@ -1,6 +1,7 @@
-use std::sync::mpsc::Receiver;
 use std::sync::{Arc, Mutex};
 
+use crossbeam_channel::Receiver;
+
 use crate::config::Config;
 use crate::dir_entry::DirEntry;
 use crate::error::print_error;
@@ -13,7 +14,7 @@ use super::CommandSet;
 /// generate a command with the supplied command template. The generated command will then
 /// be executed, and this process will continue until the receiver's sender has closed.
 pub fn job(
-    rx: Arc<Mutex<Receiver<WorkerResult>>>,
+    rx: Receiver<WorkerResult>,
     cmd: Arc<CommandSet>,
     out_perm: Arc<Mutex<()>>,
     config: &Config,
@@ -23,12 +24,9 @@ pub fn job(
 
     let mut results: Vec<ExitCode> = Vec::new();
     loop {
-        // Create a lock on the shared receiver for this thread.
-        let lock = rx.lock().unwrap();
-
         // Obtain the next result from the receiver, else if the channel
         // has closed, exit from the loop
-        let dir_entry: DirEntry = match lock.recv() {
+        let dir_entry: DirEntry = match rx.recv() {
             Ok(WorkerResult::Entry(dir_entry)) => dir_entry,
             Ok(WorkerResult::Error(err)) => {
                 if config.show_filesystem_errors {
@@ -39,8 +37,6 @@ pub fn job(
             Err(_) => break,
         };
 
-        // Drop the lock so that other threads can read from the receiver.
-        drop(lock);
         // Generate a command, execute it and store its exit code.
         results.push(cmd.execute(
             dir_entry.stripped_path(config),

src/walk.rs

@@ -3,13 +3,13 @@ use std::io;
 use std::mem;
 use std::path::PathBuf;
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::mpsc::{channel, Receiver, RecvTimeoutError, Sender};
 use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::{Duration, Instant};
 use std::{borrow::Cow, io::Write};
 
 use anyhow::{anyhow, Result};
+use crossbeam_channel::{bounded, Receiver, RecvTimeoutError, Sender};
 use ignore::overrides::OverrideBuilder;
 use ignore::{self, WalkBuilder};
 use regex::bytes::Regex;
@@ -51,7 +51,9 @@ pub const DEFAULT_MAX_BUFFER_TIME: Duration = Duration::from_millis(100);
 /// path will simply be written to standard output.
 pub fn scan(paths: &[PathBuf], pattern: Arc<Regex>, config: Arc<Config>) -> Result<ExitCode> {
     let first_path = &paths[0];
-    let (tx, rx) = channel();
+
+    // Channel capacity was chosen empircally to perform similarly to an unbounded channel
+    let (tx, rx) = bounded(0x4000 * config.threads);
 
     let mut override_builder = OverrideBuilder::new(first_path);
 
@@ -222,11 +224,7 @@ impl<W: Write> ReceiverBuffer<W> {
         match self.mode {
             ReceiverMode::Buffering => {
                 // Wait at most until we should switch to streaming
-                let now = Instant::now();
-                self.deadline
-                    .checked_duration_since(now)
-                    .ok_or(RecvTimeoutError::Timeout)
-                    .and_then(|t| self.rx.recv_timeout(t))
+                self.rx.recv_deadline(self.deadline)
             }
             ReceiverMode::Streaming => {
                 // Wait however long it takes for a result
@@ -345,15 +343,13 @@ fn spawn_receiver(
             if cmd.in_batch_mode() {
                 exec::batch(rx, cmd, &config)
             } else {
-                let shared_rx = Arc::new(Mutex::new(rx));
-
                 let out_perm = Arc::new(Mutex::new(()));
 
                 // Each spawned job will store it's thread handle in here.
                 let mut handles = Vec::with_capacity(threads);
                 for _ in 0..threads {
                     let config = Arc::clone(&config);
-                    let rx = Arc::clone(&shared_rx);
+                    let rx = rx.clone();
                     let cmd = Arc::clone(cmd);
                     let out_perm = Arc::clone(&out_perm);