Added argument parser

Fortune for enumerate-ordered's current commit: Blessing − 吉

src/args.rs

@@ -21,8 +21,9 @@ use futures::{
 #[derive(Debug, Default, Clone)]
 pub struct Args
 {
-    walker: walk::Config,
-    worker: work::Config,
+    pub reverse: bool,
+    pub walker: walk::Config,
+    pub worker: work::Config,
     paths: Option<Vec<PathBuf>>,
 }
 
@@ -258,6 +259,15 @@ where I: Iterator<Item = String>
 	};
     }
 
+    // Modes //
+    
+    // --help
+    if input == Arg::Long("help") {
+	return Ok(Some(Mode::Help));
+    }
+
+    // Normal //
+
     // -r, --recursive <limit>
     if input.is_any(args![b'r', "recursive"]) {
 	output.walker.recursion_depth = if input.is_long() {
@@ -273,16 +283,18 @@ where I: Iterator<Item = String>
 	};
     }
 
+    // -a, -m, -c, --{a,m,c}time
     if input.is_any(args![b'a', "atime"]) {
 	output.worker.by = work::OrderBy::AccessTime;
-    }
-    if input.is_any(args![b'c', "ctime"]) {
+    } else if input.is_any(args![b'c', "ctime"]) {
 	output.worker.by = work::OrderBy::CreationTime;
-    }
-    if input.is_any(args![b'm', "mtime"]) {
+    } else if input.is_any(args![b'm', "mtime"]) {
 	output.worker.by = work::OrderBy::ModifiedTime;
     }
 
+    // -n, --reverse
+    output.reverse = input.is_any(args![b'n', "reverse"]);
+
     // -P, -p, --parallel cpus|<max>
     // -1
     if input.is_any(args![b'P', b'p', "parallel"]) {

src/main.rs

@@ -59,7 +59,7 @@ where I: futures::stream::Stream<Item = P>,
 
 
 fn print_help<W: ?Sized>(to: &mut W) -> std::io::Result<()>
-    where W: std::io::Write,
+where W: std::io::Write,
 {
     let execp = args::prog_name();
     writeln!(to, "{} v{} - {}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"), env!("CARGO_PKG_DESCRIPTION"))?;
@@ -74,8 +74,8 @@ fn print_help<W: ?Sized>(to: &mut W) -> std::io::Result<()>
     macro_rules! write_opt {
 	($($name:literal),+ => $explain:literal $(, $format:expr)*) => {
 	    {
-		let names = [$($name),+].into_iter().fold(String::default(), |prev, n| format!("{prev}, {n}"));
-		writeln!(to, concat!(" {}\t\t", $explain), names $(, $format)*)
+		let names = [$($name),+].into_iter().fold(String::default(), |prev, n| if prev.is_empty() { n.to_string() } else { format!("{prev}, {n}") });
+		writeln!(to, concat!(" {}\t", $explain), names $(, $format)*)
 	    }
 	};
     }
@@ -84,6 +84,7 @@ fn print_help<W: ?Sized>(to: &mut W) -> std::io::Result<()>
     write_opt!("-a", "--atime" => "Sort by atime")?;
     write_opt!("-c", "--ctime" => "Sort by ctime (default)")?;
     write_opt!("-m", "--mtime" => "Sort by mtime")?;
+    write_opt!("-n", "--reverse" => "Print output in reverse")?;
     write_opt!("-p", "--parallel cpus|<max tasks>" => "Run tasks in parallel, with a max number of tasks being equal `<max tasks>`, or, if 0, to infinity (see `-P`), if 'cpus', to the number of logical CPU cores ({}, default)", *walk::NUM_CPUS)?;
     write_opt!("-P", "--parallel 0" => "Run tasks with unbounded parallelism, no limit to the number of walker tasks running at once (note: the physical thread pool will always be the same size regardless of these flags)")?;
     write_opt!("-1", "--parallel 1" => "Only let one directory be processed at once")?;
@@ -123,24 +124,24 @@ async fn main() -> eyre::Result<()> {
     debug!("Parsed args: {:?}", args);
     
     let worker_cfg = {
-	//TODO: Read worker config from main config
-	std::sync::Arc::new(work::Config::default())
+	//Read worker config from main config
+	std::sync::Arc::new(args.worker.clone())
     };
     let walker_cfg = {
-	//TODO: Read walker config from main config
-	walk::Config::default()
+	//Read walker config from main config
+	args.walker.clone()
     };
     
     // Spin up ordering task.
     let ordering = {
 	let cfg = (*worker_cfg).clone();
 	tokio::spawn(async move {
-	    trace!("spun up ordering backing thread");
+	    trace!("spun up ordering backing thread with config: {:?}", &cfg);
 	    work_on(cfg, rx).await //TODO: Parse config from args
 	})
     };
 
-    trace!("Starting recursive walk of input locations");
+    trace!("Starting recursive walk of input locations with config: {:?}", &walker_cfg);
     //TODO: Trace directory trees from paths in `args` and/or `stdin` and pass results to `tx`
     let walk = walk_paths(args.paths(), walker_cfg, &worker_cfg, tx);
     tokio::pin!(walk);
@@ -175,15 +176,29 @@ async fn main() -> eyre::Result<()> {
 	    let lock = std::io::stdout().lock();
 	    std::io::BufWriter::new(lock)
 	};
-	trace!("Writing ordered results to stdout... (buffered, sync)");
-	for info in set.into_iter()
+	trace!("Writing ordered results to stdout... (buffered, sync, rev: {})", args.reverse);
+	
+	#[inline] 
+	fn operate_on<W: ?Sized, I>(stdout: &mut W, set: I) -> eyre::Result<()>
+	where W: Write,
+	      I: IntoIterator<Item = work::FileInfo> + ExactSizeIterator + DoubleEndedIterator + std::iter::FusedIterator + 'static
 	{
-	    stdout.write_all(info.path().as_os_str().as_bytes())
-		.and_then(|_| stdout.write_all(&[b'\n']))
-		.wrap_err("Failed to write raw pathname for entry to stdout")
-		.with_context(|| format!("{:?}", info.path()).header("Pathname was"))?;
+	    for info in set
+	    {
+		stdout.write_all(info.path().as_os_str().as_bytes())
+		    .and_then(|_| stdout.write_all(&[b'\n']))
+		    .wrap_err("Failed to write raw pathname for entry to stdout")
+		    .with_context(|| format!("{:?}", info.path()).header("Pathname was"))?;
+	    }
+	    Ok(())
 	}
 	
+	if args.reverse {
+	    operate_on(&mut stdout, set.into_iter().rev())
+	} else {
+	    operate_on(&mut stdout, set.into_iter())
+	}.wrap_err("Abandoning output write due to failure")?;
+	
 	stdout.flush().wrap_err("Failed to flush buffered output to stdout")?;
 	Ok(())
     }).await.wrap_err("Writer (blocking) task panic")?