Address feedback for removing buffering when running on a single thread

src/exec/command.rs

@@ -7,9 +7,19 @@ use crate::error::print_error;
 use crate::exit_codes::ExitCode;
 
 /// Executes a command.
-pub fn execute_command(mut cmd: Command, out_perm: &Mutex<()>) -> ExitCode {
+pub fn execute_command(
+    mut cmd: Command,
+    out_perm: &Mutex<()>,
+    enable_output_buffering: bool,
+) -> ExitCode {
     // Spawn the supplied command.
-    let output = cmd.output();
+    let output = if enable_output_buffering {
+        cmd.output()
+    } else {
+        // If running on only one thread, don't buffer output
+        // Allows for viewing and interacting with intermediate command output
+        cmd.spawn().and_then(|c| c.wait_with_output())
+    };
 
     // Then wait for the command to exit, if it was spawned.
     match output {

src/exec/job.rs

@@ -16,6 +16,7 @@ pub fn job(
     cmd: Arc<CommandTemplate>,
     out_perm: Arc<Mutex<()>>,
     show_filesystem_errors: bool,
+    buffer_output: bool,
 ) -> ExitCode {
     let mut results: Vec<ExitCode> = Vec::new();
     loop {
@@ -38,7 +39,7 @@ pub fn job(
         // 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.generate_and_execute(&value, Arc::clone(&out_perm)))
+        results.push(cmd.generate_and_execute(&value, Arc::clone(&out_perm), buffer_output))
     }
     // Returns error in case of any error.
     merge_exitcodes(&results)
@@ -48,6 +49,7 @@ pub fn batch(
     rx: Receiver<WorkerResult>,
     cmd: &CommandTemplate,
     show_filesystem_errors: bool,
+    buffer_output: bool,
 ) -> ExitCode {
     let paths = rx.iter().filter_map(|value| match value {
         WorkerResult::Entry(val) => Some(val),
@@ -58,5 +60,5 @@ pub fn batch(
             None
         }
     });
-    cmd.generate_and_execute_batch(paths)
+    cmd.generate_and_execute_batch(paths, buffer_output)
 }

src/exec/mod.rs

@@ -139,7 +139,12 @@ impl CommandTemplate {
     ///
     /// Using the internal `args` field, and a supplied `input` variable, a `Command` will be
     /// build. Once all arguments have been processed, the command is executed.
-    pub fn generate_and_execute(&self, input: &Path, out_perm: Arc<Mutex<()>>) -> ExitCode {
+    pub fn generate_and_execute(
+        &self,
+        input: &Path,
+        out_perm: Arc<Mutex<()>>,
+        buffer_output: bool,
+    ) -> ExitCode {
         let input = strip_current_dir(input);
 
         let mut cmd = Command::new(self.args[0].generate(&input, self.path_separator.as_deref()));
@@ -147,14 +152,14 @@ impl CommandTemplate {
             cmd.arg(arg.generate(&input, self.path_separator.as_deref()));
         }
 
-        execute_command(cmd, &out_perm)
+        execute_command(cmd, &out_perm, buffer_output)
     }
 
     pub fn in_batch_mode(&self) -> bool {
         self.mode == ExecutionMode::Batch
     }
 
-    pub fn generate_and_execute_batch<I>(&self, paths: I) -> ExitCode
+    pub fn generate_and_execute_batch<I>(&self, paths: I, buffer_output: bool) -> ExitCode
     where
         I: Iterator<Item = PathBuf>,
     {
@@ -182,7 +187,7 @@ impl CommandTemplate {
         }
 
         if has_path {
-            execute_command(cmd, &Mutex::new(()))
+            execute_command(cmd, &Mutex::new(()), buffer_output)
         } else {
             ExitCode::Success
         }

src/walk.rs

@@ -170,12 +170,13 @@ fn spawn_receiver(
 
     let show_filesystem_errors = config.show_filesystem_errors;
     let threads = config.threads;
-
+    // This will be used to check if output should be buffered when only running a single thread
+    let enable_output_buffering: bool = threads > 1;
     thread::spawn(move || {
         // This will be set to `Some` if the `--exec` argument was supplied.
         if let Some(ref cmd) = config.command {
             if cmd.in_batch_mode() {
-                exec::batch(rx, cmd, show_filesystem_errors)
+                exec::batch(rx, cmd, show_filesystem_errors, enable_output_buffering)
             } else {
                 let shared_rx = Arc::new(Mutex::new(rx));
 
@@ -189,8 +190,15 @@ fn spawn_receiver(
                     let out_perm = Arc::clone(&out_perm);
 
                     // Spawn a job thread that will listen for and execute inputs.
-                    let handle =
-                        thread::spawn(move || exec::job(rx, cmd, out_perm, show_filesystem_errors));
+                    let handle = thread::spawn(move || {
+                        exec::job(
+                            rx,
+                            cmd,
+                            out_perm,
+                            show_filesystem_errors,
+                            enable_output_buffering,
+                        )
+                    });
 
                     // Push the handle of the spawned thread into the vector for later joining.
                     handles.push(handle);