du: support arbitrary time formats

src/uu/du/Cargo.toml

@@ -22,6 +22,7 @@ chrono = { workspace = true }
 # For the --exclude & --exclude-from options
 glob = { workspace = true }
 clap = { workspace = true }
+regex = { workspace = true }
 uucore = { workspace = true, features = ["format", "parser"] }
 thiserror = { workspace = true }
 

src/uu/du/src/du.rs

@@ -6,6 +6,8 @@
 use chrono::{DateTime, Local};
 use clap::{Arg, ArgAction, ArgMatches, Command, builder::PossibleValue};
 use glob::Pattern;
+use regex::Regex;
+use std::borrow::Cow;
 use std::collections::HashSet;
 use std::env;
 #[cfg(not(windows))]
@@ -20,7 +22,7 @@ use std::os::windows::fs::MetadataExt;
 use std::os::windows::io::AsRawHandle;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
-use std::sync::mpsc;
+use std::sync::{LazyLock, mpsc};
 use std::thread;
 use std::time::{Duration, UNIX_EPOCH};
 use thiserror::Error;
@@ -74,6 +76,13 @@ const ABOUT: &str = help_about!("du.md");
 const AFTER_HELP: &str = help_section!("after help", "du.md");
 const USAGE: &str = help_usage!("du.md");
 
+static TIME_STYLE_REGEX: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(
+        r"(?<before>(?:^|[^%])(?:%%)*)%(?<after>[^YCyqmbBhdeaAwuUWGgVjDxFvHkIlPpMSfRTXrZzc+stn%.369:]|[-_0][^YCyqmdewuUWGgVjHkIlMSfs%]|\.(?:[^369f]|$)|\.[369](?:[^f]|$)|[369](?:[^f]|$)|:{1,2}(?:[^z:]|$)|:{3}[^z]|$)", // cspell:disable-line
+    )
+    .unwrap()
+});
+
 struct TraversalOptions {
     all: bool,
     separate_dirs: bool,
@@ -708,7 +717,12 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     };
 
     let time_format = if time.is_some() {
-        parse_time_style(matches.get_one::<String>("time-style").map(|s| s.as_str()))?.to_string()
+        parse_time_style(
+            matches
+                .get_one::<String>(options::TIME_STYLE)
+                .map(|s| s.as_str()),
+        )?
+        .to_string()
     } else {
         "%Y-%m-%d %H:%M".to_string()
     };
@@ -801,15 +815,38 @@ fn get_time_secs(time: Time, stat: &Stat) -> Result<u64, DuError> {
     }
 }
 
-fn parse_time_style(s: Option<&str>) -> UResult<&str> {
-    match s {
+fn parse_time_style(s: Option<&str>) -> UResult<Cow<'_, str>> {
+    let s = match s {
         Some(s) => match s {
             "full-iso" => Ok("%Y-%m-%d %H:%M:%S.%f %z"),
             "long-iso" => Ok("%Y-%m-%d %H:%M"),
             "iso" => Ok("%Y-%m-%d"),
-            _ => Err(DuError::InvalidTimeStyleArg(s.into()).into()),
+            _ => match s.strip_prefix('+') {
+                Some(s) => Ok(s),
+                _ => Err(DuError::InvalidTimeStyleArg(s.into()).into()),
+            },
         },
         None => Ok("%Y-%m-%d %H:%M"),
+    };
+    match s {
+        Ok(s) => {
+            let mut s = s.to_owned();
+            let mut start = 0;
+            while start < s.len() {
+                // FIXME: this should use let chains once they're stabilized
+                // See https://github.com/rust-lang/rust/issues/53667
+                if let Some(cap) = TIME_STYLE_REGEX.captures(&s[start..]) {
+                    let mat = cap.name("before").unwrap();
+                    let percent_idx = mat.end();
+                    s.replace_range(percent_idx + start..=percent_idx + start, "%%");
+                    start = percent_idx + 2;
+                } else {
+                    break;
+                }
+            }
+            Ok(Cow::Owned(s))
+        }
+        Err(e) => Err(e),
     }
 }
 

tests/by-util/test_du.rs

@@ -7,6 +7,7 @@
 #[cfg(not(windows))]
 use regex::Regex;
 
+use rstest::rstest;
 use uutests::at_and_ucmd;
 use uutests::new_ucmd;
 #[cfg(not(target_os = "windows"))]
@@ -1169,6 +1170,53 @@ fn test_invalid_time_style() {
         .stdout_does_not_contain("du: invalid argument 'banana' for 'time style'");
 }
 
+#[rstest]
+#[case::full_iso("+%Y-%m-%d %H:%M:%S.%f %z")]
+#[case::long_iso("+%Y-%m-%d %H:%M")]
+#[case::iso("+%Y-%m-%d")]
+#[case::seconds("+%S")]
+fn test_valid_time_style(#[case] input: &str) {
+    new_ucmd!()
+        .args(&["--time", "--time-style", input])
+        .succeeds();
+}
+
+#[test]
+fn test_time_style_escaping() {
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    at.touch("date_test");
+
+    // printable characters (a little overkill, but better than missing something)
+    for c in '!'..='~' {
+        let f = format!("+%{c}");
+        ts.ucmd()
+            .arg("--time")
+            .arg("--time-style")
+            .arg(f)
+            .arg("date_test")
+            .succeeds();
+        for prefix in ".:#0-_".chars() {
+            let f = format!("+%{prefix}{c}");
+            ts.ucmd()
+                .arg("--time")
+                .arg("--time-style")
+                .arg(f)
+                .arg("date_test")
+                .succeeds();
+        }
+    }
+
+    let f = "+%%%";
+    ts.ucmd()
+        .arg("--time")
+        .arg("--time-style")
+        .arg(f)
+        .arg("date_test")
+        .succeeds();
+}
+
 #[test]
 fn test_human_size() {
     use std::fs::File;