ls: add support for +FORMAT in timestyle

src/uu/ls/src/ls.rs

@@ -10,7 +10,10 @@
 #[macro_use]
 extern crate uucore;
 
-use clap::{builder::ValueParser, crate_version, Arg, Command};
+use clap::{
+    builder::{NonEmptyStringValueParser, ValueParser},
+    crate_version, Arg, Command,
+};
 use glob::Pattern;
 use lscolors::LsColors;
 use number_prefix::NumberPrefix;
@@ -156,6 +159,7 @@ enum LsError {
     IOErrorContext(std::io::Error, PathBuf, bool),
     BlockSizeParseError(String),
     AlreadyListedError(PathBuf),
+    TimeStyleParseError(String, Vec<String>),
 }
 
 impl UError for LsError {
@@ -167,6 +171,7 @@ impl UError for LsError {
             Self::IOErrorContext(_, _, true) => 2,
             Self::BlockSizeParseError(_) => 1,
             Self::AlreadyListedError(_) => 2,
+            Self::TimeStyleParseError(_, _) => 1,
         }
     }
 }
@@ -179,6 +184,14 @@ impl Display for LsError {
             Self::BlockSizeParseError(s) => {
                 write!(f, "invalid --block-size argument {}", s.quote())
             }
+            Self::TimeStyleParseError(s, possible_time_styles) => {
+                write!(
+                    f,
+                    "invalid --time-style argument {}\nPossible values are: {:?}\n\nFor more information try --help",
+                    s.quote(),
+                    possible_time_styles
+                )
+            }
             Self::InvalidLineWidth(s) => write!(f, "invalid line width: {}", s.quote()),
             Self::IOError(e) => write!(f, "general io error: {}", e),
             Self::IOErrorContext(e, p, _) => {
@@ -300,8 +313,46 @@ enum TimeStyle {
     LongIso,
     Iso,
     Locale,
+    Format(String),
 }
 
+fn parse_time_style(options: &clap::ArgMatches) -> Result<TimeStyle, LsError> {
+    let possible_time_styles = vec![
+        "full-iso".to_string(),
+        "long-iso".to_string(),
+        "iso".to_string(),
+        "locale".to_string(),
+        "+FORMAT (e.g., +%H:%M) for a 'date'-style format".to_string(),
+    ];
+    if let Some(field) = options.get_one::<String>(options::TIME_STYLE) {
+        //If both FULL_TIME and TIME_STYLE are present
+        //The one added last is dominant
+        if options.contains_id(options::FULL_TIME)
+            && options.indices_of(options::FULL_TIME).unwrap().last()
+                > options.indices_of(options::TIME_STYLE).unwrap().last()
+        {
+            Ok(TimeStyle::FullIso)
+        } else {
+            match field.as_str() {
+                "full-iso" => Ok(TimeStyle::FullIso),
+                "long-iso" => Ok(TimeStyle::LongIso),
+                "iso" => Ok(TimeStyle::Iso),
+                "locale" => Ok(TimeStyle::Locale),
+                _ => match field.chars().next().unwrap() {
+                    '+' => Ok(TimeStyle::Format(String::from(&field[1..]))),
+                    _ => Err(LsError::TimeStyleParseError(
+                        String::from(field),
+                        possible_time_styles,
+                    )),
+                },
+            }
+        }
+    } else if options.contains_id(options::FULL_TIME) {
+        Ok(TimeStyle::FullIso)
+    } else {
+        Ok(TimeStyle::Locale)
+    }
+}
 enum Dereference {
     None,
     DirArgs,
@@ -700,31 +751,7 @@ impl Config {
         } else {
             IndicatorStyle::None
         };
-
+        let time_style = parse_time_style(options)?;
-        let time_style = if let Some(field) = options.get_one::<String>(options::TIME_STYLE) {
-            //If both FULL_TIME and TIME_STYLE are present
-            //The one added last is dominant
-            if options.contains_id(options::FULL_TIME)
-                && options.indices_of(options::FULL_TIME).unwrap().last()
-                    > options.indices_of(options::TIME_STYLE).unwrap().last()
-            {
-                TimeStyle::FullIso
-            } else {
-                //Clap handles the env variable "TIME_STYLE"
-                match field.as_str() {
-                    "full-iso" => TimeStyle::FullIso,
-                    "long-iso" => TimeStyle::LongIso,
-                    "iso" => TimeStyle::Iso,
-                    "locale" => TimeStyle::Locale,
-                    // below should never happen as clap already restricts the values.
-                    _ => unreachable!("Invalid field for --time-style"),
-                }
-            }
-        } else if options.contains_id(options::FULL_TIME) {
-            TimeStyle::FullIso
-        } else {
-            TimeStyle::Locale
-        };
 
         let mut ignore_patterns: Vec<Pattern> = Vec::new();
 
@@ -1511,13 +1538,13 @@ pub fn uu_app<'a>() -> Command<'a> {
                 ]),
         )
         .arg(
-            //This still needs support for posix-*, +FORMAT
+            //This still needs support for posix-*
             Arg::new(options::TIME_STYLE)
                 .long(options::TIME_STYLE)
                 .help("time/date format with -l; see TIME_STYLE below")
                 .value_name("TIME_STYLE")
                 .env("TIME_STYLE")
-                .value_parser(["full-iso", "long-iso", "iso", "locale"])
+                .value_parser(NonEmptyStringValueParser::new())
                 .overrides_with_all(&[options::TIME_STYLE]),
         )
         .arg(
@@ -1549,7 +1576,7 @@ pub fn uu_app<'a>() -> Command<'a> {
                 .value_parser(ValueParser::os_string()),
         )
         .after_help(
-            "The TIME_STYLE argument can be full-iso, long-iso, iso. \
+            "The TIME_STYLE argument can be full-iso, long-iso, iso, locale or +FORMAT. FORMAT is interpreted like in date. \
             Also the TIME_STYLE environment variable sets the default style to use.",
         )
 }
@@ -2519,7 +2546,7 @@ fn display_date(metadata: &Metadata, config: &Config) -> String {
             //According to GNU a Gregorian year has 365.2425 * 24 * 60 * 60 == 31556952 seconds on the average.
             let recent = time + chrono::Duration::seconds(31_556_952 / 2) > chrono::Local::now();
 
-            match config.time_style {
+            match &config.time_style {
                 TimeStyle::FullIso => time.format("%Y-%m-%d %H:%M:%S.%f %z"),
                 TimeStyle::LongIso => time.format("%Y-%m-%d %H:%M"),
                 TimeStyle::Iso => time.format(if recent { "%m-%d %H:%M" } else { "%Y-%m-%d " }),
@@ -2534,6 +2561,7 @@ fn display_date(metadata: &Metadata, config: &Config) -> String {
 
                     time.format(fmt)
                 }
+                TimeStyle::Format(e) => time.format(e),
             }
             .to_string()
         }

tests/by-util/test_ls.rs

@@ -1653,6 +1653,7 @@ fn test_ls_styles() {
     let re_iso = Regex::new(r"[a-z-]* \d* \w* \w* \d* \d{2}-\d{2} \d{2}:\d{2} test\n").unwrap();
     let re_locale =
         Regex::new(r"[a-z-]* \d* \w* \w* \d* [A-Z][a-z]{2} ( |\d)\d \d{2}:\d{2} test\n").unwrap();
+    let re_custom_format = Regex::new(r"[a-z-]* \d* \w* \w* \d* \d{4}__\d{2} test\n").unwrap();
 
     //full-iso
     let result = scene
@@ -1675,6 +1676,17 @@ fn test_ls_styles() {
     let result = scene.ucmd().arg("-l").arg("--time-style=locale").succeeds();
     assert!(re_locale.is_match(result.stdout_str()));
 
+    //+FORMAT
+    let result = scene
+        .ucmd()
+        .arg("-l")
+        .arg("--time-style=+%Y__%M")
+        .succeeds();
+    assert!(re_custom_format.is_match(result.stdout_str()));
+
+    // Also fails due to not having full clap support for time_styles
+    scene.ucmd().arg("-l").arg("-time-style=invalid").fails();
+
     //Overwrite options tests
     let result = scene
         .ucmd()