ls: display %Z alphabetic time zone abbreviation

Display the alphabetic timezone abbreviation (like "UTC" or "CET") when
the `--time-style` argument includes a `%Z` directive. This matches the
behavior of `date`.

Fixes #7035

src/uu/ls/Cargo.toml

@@ -18,13 +18,17 @@ path = "src/ls.rs"
 
 [dependencies]
 ansi-width = { workspace = true }
-clap = { workspace = true, features = ["env"] }
 chrono = { workspace = true }
-number_prefix = { workspace = true }
-uutils_term_grid = { workspace = true }
-terminal_size = { workspace = true }
+chrono-tz = { workspace = true }
+clap = { workspace = true, features = ["env"] }
 glob = { workspace = true }
+hostname = { workspace = true }
+iana-time-zone = { workspace = true }
 lscolors = { workspace = true }
+number_prefix = { workspace = true }
+once_cell = { workspace = true }
+selinux = { workspace = true, optional = true }
+terminal_size = { workspace = true }
 uucore = { workspace = true, features = [
   "colors",
   "entries",
@@ -34,9 +38,7 @@ uucore = { workspace = true, features = [
   "quoting-style",
   "version-cmp",
 ] }
-once_cell = { workspace = true }
-selinux = { workspace = true, optional = true }
-hostname = { workspace = true }
+uutils_term_grid = { workspace = true }
 
 [[bin]]
 name = "ls"

src/uu/ls/src/ls.rs

@@ -5,19 +5,9 @@
 
 // spell-checker:ignore (ToDO) somegroup nlink tabsize dired subdired dtype colorterm stringly
 
-use clap::{
-    builder::{NonEmptyStringValueParser, PossibleValue, ValueParser},
-    crate_version, Arg, ArgAction, Command,
-};
-use glob::{MatchOptions, Pattern};
-use lscolors::LsColors;
-
-use ansi_width::ansi_width;
-use std::{cell::OnceCell, num::IntErrorKind};
-use std::{collections::HashSet, io::IsTerminal};
-
 #[cfg(windows)]
 use std::os::windows::fs::MetadataExt;
+use std::{cell::OnceCell, num::IntErrorKind};
 use std::{
     cmp::Reverse,
     error::Error,
@@ -34,7 +24,20 @@ use std::{
     os::unix::fs::{FileTypeExt, MetadataExt},
     time::Duration,
 };
+use std::{collections::HashSet, io::IsTerminal};
+
+use ansi_width::ansi_width;
+use chrono::{DateTime, Local, TimeDelta, TimeZone, Utc};
+use chrono_tz::{OffsetName, Tz};
+use clap::{
+    builder::{NonEmptyStringValueParser, PossibleValue, ValueParser},
+    crate_version, Arg, ArgAction, Command,
+};
+use glob::{MatchOptions, Pattern};
+use iana_time_zone::get_timezone;
+use lscolors::LsColors;
 use term_grid::{Direction, Filling, Grid, GridOptions};
+
 use uucore::error::USimpleError;
 use uucore::format::human::{human_readable, SizeFormat};
 #[cfg(all(unix, not(any(target_os = "android", target_os = "macos"))))]
@@ -67,10 +70,12 @@ use uucore::{
     version_cmp::version_cmp,
 };
 use uucore::{help_about, help_section, help_usage, parse_glob, show, show_error, show_warning};
+
 mod dired;
 use dired::{is_dired_arg_present, DiredOutput};
 mod colors;
 use colors::{color_name, StyleManager};
+
 #[cfg(not(feature = "selinux"))]
 static CONTEXT_HELP_TEXT: &str = "print any security context of each file (not enabled)";
 #[cfg(feature = "selinux")]
@@ -334,6 +339,37 @@ enum TimeStyle {
     Format(String),
 }
 
+/// Whether the given date is considered recent (i.e., in the last 6 months).
+fn is_recent(time: DateTime<Local>) -> bool {
+    // According to GNU a Gregorian year has 365.2425 * 24 * 60 * 60 == 31556952 seconds on the average.
+    time + TimeDelta::try_seconds(31_556_952 / 2).unwrap() > Local::now()
+}
+
+/// Get the alphabetic abbreviation of the current timezone.
+///
+/// For example, "UTC" or "CET" or "PDT".
+fn timezone_abbrev() -> String {
+    let tz = match std::env::var("TZ") {
+        // TODO Support other time zones...
+        Ok(s) if s == "UTC0" || s.is_empty() => Tz::Etc__UTC,
+        _ => match get_timezone() {
+            Ok(tz_str) => tz_str.parse().unwrap(),
+            Err(_) => Tz::Etc__UTC,
+        },
+    };
+    let offset = tz.offset_from_utc_date(&Utc::now().date_naive());
+    offset.abbreviation().unwrap_or("UTC").to_string()
+}
+
+/// Format the given time according to a custom format string.
+fn custom_time_format(fmt: &str, time: DateTime<Local>) -> String {
+    // TODO Refactor the common code from `ls` and `date` for rendering dates.
+    // TODO - Revisit when chrono 0.5 is released. https://github.com/chronotope/chrono/issues/970
+    // GNU `date` uses `%N` for nano seconds, however the `chrono` crate uses `%f`.
+    let fmt = fmt.replace("%N", "%f").replace("%Z", &timezone_abbrev());
+    time.format(&fmt).to_string()
+}
+
 impl TimeStyle {
     /// Format the given time according to this time format style.
     fn format(&self, time: DateTime<Local>) -> String {
@@ -350,7 +386,7 @@ impl TimeStyle {
             //So it's not yet implemented
             (Self::Locale, true) => time.format("%b %e %H:%M").to_string(),
             (Self::Locale, false) => time.format("%b %e  %Y").to_string(),
-            (Self::Format(e), _) => time.format(e).to_string(),
+            (Self::Format(e), _) => custom_time_format(e, time),
         }
     }
 }

tests/by-util/test_ls.rs

@@ -5628,3 +5628,14 @@ fn test_non_unicode_names() {
         .succeeds()
         .stdout_is_bytes(b"\xC0.dir\n\xC0.file\n");
 }
+
+#[test]
+fn test_time_style_timezone_name() {
+    let re_custom_format = Regex::new(r"[a-z-]* \d* [\w.]* [\w.]* \d* UTC f\n").unwrap();
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.touch("f");
+    ucmd.env("TZ", "UTC0")
+        .args(&["-l", "--time-style=+%Z"])
+        .succeeds()
+        .stdout_matches(&re_custom_format);
+}