Added argument parsing.

Fortune for enumerate-ordered's current commit: Half curse − 半凶

Cargo.lock

@@ -102,7 +102,9 @@ dependencies = [
  "color-eyre",
  "futures",
  "jemallocator",
+ "lazy_static",
  "log",
+ "num_cpus",
  "pretty_env_logger",
  "tokio",
  "tokio-stream",
@@ -277,6 +279,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
 [[package]]
 name = "libc"
 version = "0.2.137"

Cargo.toml

@@ -15,7 +15,9 @@ strip = false
 color-eyre = { version = "0.6.2", default-features = false }
 futures = "0.3.25"
 jemallocator = "0.5.0"
+lazy_static = "1.4.0"
 log = "0.4.17"
+num_cpus = "1.14.0"
 pretty_env_logger = "0.4.0"
 tokio = { version = "1.22.0", features = ["full"] }
 tokio-stream = { version = "0.1.11", features = ["sync", "fs", "io-util", "net", "signal", "tokio-util"] }

src/args.rs

@@ -6,6 +6,7 @@ use std::{
 	Path, PathBuf,
     },
     borrow::Cow,
+    fmt,
 };
 use tokio::{
     sync::{
@@ -17,9 +18,11 @@ use futures::{
 };
 
 /// Parsed command-line args
-#[derive(Debug)]
+#[derive(Debug, Default, Clone)]
 pub struct Args
 {
+    walker: walk::Config,
+    worker: work::Config,
     paths: Option<Vec<PathBuf>>,
 }
 
@@ -83,11 +86,278 @@ impl Args
     }
 }
 
+#[derive(Debug, Clone)]
+pub enum Mode
+{
+    Normal(Args),
+    Help,
+}
+
 #[inline] 
-pub fn parse_args() -> eyre::Result<Args>
+pub fn parse_args() -> eyre::Result<Mode>
 {
     //return Ok(Args { paths: None });
-    todo!("parse(std::env::args().skip(1))")
+    parse(std::env::args().skip(1))
+        .with_context(|| format!("{:?}", std::env::args().collect::<Vec<_>>()).header("ARGV was"))
+}
+
+/// The executable name, if readable from argv as a valid UTF8 string.
+///
+/// If not readable, the project name will be returned.
+#[inline] 
+pub fn prog_name() -> &'static str
+{
+    lazy_static! {
+	static ref PROG_NAME: &'static str = std::env::args().next().map(|x| &*Box::leak(x.into_boxed_str())).unwrap_or(env!("CARGO_PKG_NAME"));
+    }
+    *PROG_NAME
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Copy)]
+enum Arg<'a>
+{
+    Long(&'a str),
+    Short(&'a [u8]),
+    ShortSingle(u8),
+}
+
+impl<'a> Arg<'a>
+{
+    #[inline] 
+    pub fn as_long(&self) -> Option<&'a str>
+    {
+	match self {
+	    Self::Long(l) => Some(l),
+	    _ => None,
+	}
+    }
+    #[inline] 
+    pub fn as_short_ascii(&self) -> Option<&'a [u8]>
+    {
+	match self {
+	    Self::Short(l) => Some(l),
+	    //Self::ShortSingle(s) => Some(&[*s]),
+	    _ => None,
+	}
+    }
+    #[inline] 
+    pub fn split_short(&self) -> Option<impl IntoIterator<Item = char> + 'a>
+    {
+	self.as_short_ascii().map(|x| std::str::from_utf8(x).ok() /* XXX: Silent failure is not a good idea.. We should return an error (or maybe just panic? if there's invalid utf8 here, it shouldn't happen)*/).flatten().map(|s| s.chars())
+    }
+
+    #[inline] 
+    pub fn split_short_ascii(&self) -> Option<impl Iterator<Item = u8> + 'a>
+    {
+	self.as_short_ascii().map(|opt| opt.into_iter().copied())
+    }
+
+    #[inline] 
+    pub fn explode(self) -> impl Iterator<Item = Arg<'a>> + 'a
+    {
+	std::iter::once(self)
+	    .chain(std::iter::once(if let Self::Short(short) = self { Some(short.into_iter().copied().map(|x| Arg::ShortSingle(x))) } else { None })
+		   .flat_map(std::convert::identity).flatten())
+    }
+
+    #[inline] 
+    pub fn is_any<'b: 'a, I: 'b, A>(&self, these: I) -> bool
+    where I: IntoIterator<Item = A>,
+	  A: Into<Arg<'b>> + 'b
+    {
+	let iter: Vec<_> = these.into_iter().map(Into::into).map(|x| x.explode()).flatten().collect();
+	for split in self.explode() {
+	    if iter.iter().any(|arg| arg == &split) {
+		return true;
+	    }
+	}
+	false
+    }
+
+    #[inline(always)]
+    pub fn is_long(&self) -> bool
+    {
+	self.as_long().is_some()
+    }
+
+    #[inline(always)] 
+    pub fn is_short(&self) -> bool
+    {
+	!self.is_long()
+    }
+}
+
+impl<'a> fmt::Display for Arg<'a>
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    {
+	match self {
+	    Self::Long(s) => write!(f, "--{s}"),
+	    Self::Short(short) => write!(f, "-{}", std::str::from_utf8(short).unwrap()),
+	    Self::ShortSingle(one) => write!(f, "-{}", *one as char),
+	}
+    }
+}
+
+impl<'a> From<&'a [u8]> for Arg<'a>
+{
+    #[inline] 
+    fn from(from: &'a [u8]) -> Self
+    {
+	Self::Short(from)
+    }
+}
+
+impl<'a, const N: usize> From<&'a [u8; N]> for Arg<'a>
+{
+    #[inline] 
+    fn from(from: &'a [u8; N]) -> Self
+    {
+	Self::Short(&from[..])
+    }
+}
+
+
+impl<'a> From<&'a str> for Arg<'a>
+{
+    #[inline] 
+    fn from(from: &'a str) -> Self
+    {
+	Self::Long(from)
+    }
+}
+
+impl From<u8> for Arg<'static>
+{
+    #[inline] 
+    fn from(from: u8) -> Self
+    {
+	Self::ShortSingle(from)
+    }
+}
+
+#[inline] 
+fn parse_single<'a, I: ?Sized + 'a>(input: Arg<'a>, args: &mut I, output: &mut Args) -> eyre::Result<Option<Mode>>
+where I: Iterator<Item = String>
+{
+    macro_rules! take {
+	($fmt:literal $(, $ag:expr)*) => {
+            match args.next() {
+		Some(n) => n,
+		None => return Err(eyre!($fmt $(, $ag)*)),
+	    }
+	};
+	() => {
+	    take!("`{}` expects an argument", &input)
+	}
+    }
+
+    macro_rules! args {
+	($($arg:expr),*) => {
+            [$(Arg::from($arg)),*]
+	};
+    }
+
+    // -r, --recursive <limit>
+    if input.is_any(args![b'r', "recursive"]) {
+	output.walker.recursion_depth = if input.is_long() {
+	    let limit = take!();
+	    let limit: usize = (&limit).parse().wrap_err("`--recursive` expects a positive integer")
+		.with_section(move || limit.header("Invalid parameter was"))?;
+	    match limit {
+		0 => None,
+		n => Some(n),
+	    }
+	} else {
+	    None
+	};
+    }
+
+    if input.is_any(args![b'a', "atime"]) {
+	output.worker.by = work::OrderBy::AccessTime;
+    }
+    if input.is_any(args![b'c', "ctime"]) {
+	output.worker.by = work::OrderBy::CreationTime;
+    }
+    if input.is_any(args![b'm', "mtime"]) {
+	output.worker.by = work::OrderBy::ModifiedTime;
+    }
+
+    // -P, -p, --parallel cpus|<max>
+    // -1
+    if input.is_any(args![b'P', b'p', "parallel"]) {
+	if input.is_long() {
+	    let mut num = take!();
+	    if let Ok(n) = num.parse() {
+		output.walker.max_walkers = std::num::NonZeroUsize::new(n);
+	    } else {
+		num.make_ascii_lowercase();
+		match &num[..] {
+		    "cpus" => output.walker.max_walkers = std::num::NonZeroUsize::new(*walk::NUM_CPUS),
+		    _ => return Err(eyre!("`--parallel` expects a positive integer or the string 'cpus'")).with_context(move || num.header("Invalid parameter was")),
+		}
+	    }
+	} else {
+	    output.walker.max_walkers = if input.is_any(*b"P") {
+		None
+	    } else {
+		std::num::NonZeroUsize::new(*walk::NUM_CPUS)
+	    };
+	}
+    } else if input.is_any(args![b'1']) {
+	output.walker.max_walkers = std::num::NonZeroUsize::new(1);
+    }
+    
+    Ok(None)
+}
+
+fn parse(args: impl IntoIterator<Item=String>) -> eyre::Result<Mode>
+{
+    let mut output = Args::default();
+    let mut args = args.into_iter().fuse();
+
+    let mut rest = Vec::new();
+    while let Some(current) = args.next()
+    {
+	
+	macro_rules! single {
+	    ($input:expr) => {
+		{
+		    let input = Arg::from($input);
+		    if let Some(mode) = parse_single($input, &mut args, &mut output)
+			.wrap_err(eyre!("Parsing error for argument '{}'", &input))
+			.with_section(|| current.clone().header("Current arg was"))?
+		    {
+			return Ok(mode);
+		    }
+		}
+	    };
+	}
+	match current.as_bytes() {
+	    b"-" |
+	    b"--" => break,
+	    [b'-', b'-',  ..] => {
+		// Long opt
+		single!(Arg::Long(&current[2..]));
+	    },
+	    [b'-', short @ ..] => {
+		// Short opts
+		single!(Arg::Short(short))
+	    },
+	    _ => {
+		// Not an opt, a path.
+		rest.push(PathBuf::from(current));
+		break;
+	    },
+	}
+    }
+    rest.extend(args.map(Into::into));
+    output.paths = match rest {
+	empty if empty.is_empty() => None,
+	rest => Some(rest),
+    };
+    
+    Ok(Mode::Normal(output))
 }
 
 //TODO: fn parse(args: impl IntoIterator<Item=String>) -> eyre::Result<Args>

src/main.rs

@@ -1,6 +1,6 @@
 
 #[macro_use] extern crate log;
-
+#[macro_use] extern crate lazy_static;
 use color_eyre::{
     eyre::{
 	self,
@@ -57,6 +57,54 @@ where I: futures::stream::Stream<Item = P>,
     Ok(children.into_iter().sum())
 }
 
+
+fn print_help<W: ?Sized>(to: &mut W) -> std::io::Result<()>
+    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"))?;
+    writeln!(to, " GPL'd with <3 by {}", env!("CARGO_PKG_AUTHORS"))?;
+    writeln!(to, "\nUsage:")?;
+    writeln!(to, "{execp} [OPTIONS] [--] [<files...>]")?;
+    writeln!(to, "\tAccording to OPTIONS, given input file paths `files...` (or, if empty, paths read from `stdin`), write them to `stdout` ordered by their metadata's timecodes")?;
+    writeln!(to, "{execp} --help")?;
+    writeln!(to, "\tPrint this message to `stderr`, then exit with code 0.")?;
+    writeln!(to, "")?;
+    writeln!(to, "OPTIONS:")?;
+    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)*)
+	    }
+	};
+    }
+    
+    write_opt!("-r", "--recursive <limit>" => "Recursively sort input files, up to `<limit>` (set to 0 for infniite); if limit is not specified, recursion is infinite")?;
+    write_opt!("-a", "--atime" => "Sort by atime")?;
+    write_opt!("-c", "--ctime" => "Sort by ctime (default)")?;
+    write_opt!("-m", "--mtime" => "Sort by mtime")?;
+    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")?;
+    write_opt!("-", "--" => "Stop parsing arguments, treat the rest as input paths")?;
+    
+    //TODO: Allow controlling failure modes (currently it's hardcoded when walking will fail and why and also kind arbitary; it being controllable would be better).
+    
+    writeln!(to, "")?;
+
+    writeln!(to, "ENV VARS:")?;
+    writeln!(to, "`RUST_LOG` - Control the logging (to stderr) level.")?;
+    writeln!(to, r#" "none" - No output.
+ "error" - Errors only.
+ "warn" - Warnings and above.
+ "info" - Information and above.
+ "debug" - Debug information and above.
+ "trace" - All recorded information."#)?;
+    
+    Ok(())
+}
+
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
     init_logging().wrap_err("Failed to set logging handlers")?;
@@ -65,9 +113,14 @@ async fn main() -> eyre::Result<()> {
 
     //TODO: Read main config from args
 
-    let args = args::parse_args()
+    let args = match args::parse_args()
 	.wrap_err("Failed to parse command line args")
-	.with_suggestion(|| "Try `--help`")?;
+	.with_suggestion(|| "Try `--help`")?
+    {
+	args::Mode::Normal(n) => n,
+	args::Mode::Help => return print_help(&mut std::io::stderr().lock()).wrap_err("Failed to write help to stderr"),
+    };
+    debug!("Parsed args: {:?}", args);
     
     let worker_cfg = {
 	//TODO: Read worker config from main config

src/walk.rs

@@ -19,7 +19,20 @@ use futures::future::{
     BoxFuture,
 };
 
-#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Default)]
+
+lazy_static! {
+    pub(super) static ref NUM_CPUS: usize = num_cpus::get();
+}
+
+/// Default number of max walkers allowed to work at once on the thread pool.
+/// See `Config`.
+#[inline] 
+pub fn default_max_walkers() -> Option<NonZeroUsize>
+{
+    NonZeroUsize::new(*NUM_CPUS)
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct Config
 {
     // None: unlimited. 0: no recursion
@@ -28,6 +41,19 @@ pub struct Config
     pub max_walkers: Option<NonZeroUsize>,
 }
 
+impl Default for Config
+{
+    #[inline]
+    fn default() -> Self
+    {
+	Self {
+	    recursion_depth: Some(0),
+	    max_walkers: default_max_walkers(),
+	}
+    }
+}
+
+
 #[derive(Debug, Clone)]
 struct UniqueState
 {