pr: Add support for -D/--date-format parameter

src/uu/pr/Cargo.toml

@@ -19,10 +19,9 @@ path = "src/pr.rs"
 
 [dependencies]
 clap = { workspace = true }
-uucore = { workspace = true, features = ["entries"] }
+uucore = { workspace = true, features = ["entries", "time"] }
 itertools = { workspace = true }
 regex = { workspace = true }
-chrono = { workspace = true }
 thiserror = { workspace = true }
 fluent = { workspace = true }
 

src/uu/pr/locales/en-US.ftl

@@ -13,6 +13,8 @@ pr-help-pages = Begin and stop printing with page FIRST_PAGE[:LAST_PAGE]
 pr-help-header =
   Use the string header to replace the file name
                   in the header line.
+pr-help-date-format =
+  Use 'date'-style FORMAT for the header date.
 pr-help-double-space =
   Produce output that is double spaced. An extra <newline>
                   character is output following every <newline> found in the input.

src/uu/pr/locales/fr-FR.ftl

@@ -13,6 +13,8 @@ pr-help-pages = Commencer et arrêter l'impression à la page PREMIÈRE_PAGE[:DE
 pr-help-header =
   Utiliser la chaîne d'en-tête pour remplacer le nom de fichier
                   dans la ligne d'en-tête.
+pr-help-date-format =
+  Utiliser le FORMAT de style 'date' pour la date dans la ligne d'en-tête.
 pr-help-double-space =
   Produire une sortie avec double espacement. Un caractère <saut de ligne>
                   supplémentaire est affiché après chaque <saut de ligne> trouvé dans l'entrée.

src/uu/pr/src/pr.rs

@@ -6,19 +6,20 @@
 
 // spell-checker:ignore (ToDO) adFfmprt, kmerge
 
-use chrono::{DateTime, Local};
 use clap::{Arg, ArgAction, ArgMatches, Command};
 use itertools::Itertools;
 use regex::Regex;
 use std::fs::{File, metadata};
 use std::io::{BufRead, BufReader, Lines, Read, Write, stdin, stdout};
 #[cfg(unix)]
 use std::os::unix::fs::FileTypeExt;
+use std::time::SystemTime;
 use thiserror::Error;
 
 use uucore::display::Quotable;
 use uucore::error::UResult;
 use uucore::format_usage;
+use uucore::time::{FormatSystemTimeFallback, format, format_system_time};
 use uucore::translate;
 
 const TAB: char = '\t';
@@ -32,10 +33,10 @@ const DEFAULT_COLUMN_WIDTH: usize = 72;
 const DEFAULT_COLUMN_WIDTH_WITH_S_OPTION: usize = 512;
 const DEFAULT_COLUMN_SEPARATOR: &char = &TAB;
 const FF: u8 = 0x0C_u8;
-const DATE_TIME_FORMAT: &str = "%b %d %H:%M %Y";
 
 mod options {
     pub const HEADER: &str = "header";
+    pub const DATE_FORMAT: &str = "date-format";
     pub const DOUBLE_SPACE: &str = "double-space";
     pub const NUMBER_LINES: &str = "number-lines";
     pub const FIRST_LINE_NUMBER: &str = "first-line-number";
@@ -176,6 +177,13 @@ pub fn uu_app() -> Command {
                 .help(translate!("pr-help-header"))
                 .value_name("STRING"),
         )
+        .arg(
+            Arg::new(options::DATE_FORMAT)
+                .short('D')
+                .long(options::DATE_FORMAT)
+                .value_name("FORMAT")
+                .help(translate!("pr-help-date-format")),
+        )
         .arg(
             Arg::new(options::DOUBLE_SPACE)
                 .short('d')
@@ -401,6 +409,25 @@ fn parse_usize(matches: &ArgMatches, opt: &str) -> Option<Result<usize, PrError>
         .map(from_parse_error_to_pr_error)
 }
 
+fn get_date_format(matches: &ArgMatches) -> String {
+    match matches.get_one::<String>(options::DATE_FORMAT) {
+        Some(format) => format,
+        None => {
+            // Replicate behavior from GNU manual.
+            if std::env::var("POSIXLY_CORRECT").is_ok()
+                // TODO: This needs to be moved to uucore and handled by icu?
+                && (std::env::var("LC_TIME").unwrap_or_default() == "POSIX"
+                    || std::env::var("LC_ALL").unwrap_or_default() == "POSIX")
+            {
+                "%b %e %H:%M %Y"
+            } else {
+                format::LONG_ISO
+            }
+        }
+    }
+    .to_string()
+}
+
 #[allow(clippy::cognitive_complexity)]
 fn build_options(
     matches: &ArgMatches,
@@ -487,11 +514,26 @@ fn build_options(
 
     let line_separator = "\n".to_string();
 
-    let last_modified_time = if is_merge_mode || paths[0].eq(FILE_STDIN) {
-        let date_time = Local::now();
-        date_time.format(DATE_TIME_FORMAT).to_string()
-    } else {
-        file_last_modified_time(paths.first().unwrap())
+    let last_modified_time = {
+        let mut v = Vec::new();
+        let time = if is_merge_mode || paths[0].eq(FILE_STDIN) {
+            Some(SystemTime::now())
+        } else {
+            metadata(paths.first().unwrap())
+                .ok()
+                .and_then(|i| i.modified().ok())
+        };
+        time.and_then(|time| {
+            format_system_time(
+                &mut v,
+                time,
+                &get_date_format(matches),
+                FormatSystemTimeFallback::Integer,
+            )
+            .ok()
+        })
+        .map(|()| String::from_utf8_lossy(&v).to_string())
+        .unwrap_or_default()
     };
 
     // +page option is less priority than --pages
@@ -1126,19 +1168,6 @@ fn header_content(options: &OutputOptions, page: usize) -> Vec<String> {
     }
 }
 
-fn file_last_modified_time(path: &str) -> String {
-    metadata(path)
-        .map(|i| {
-            i.modified()
-                .map(|x| {
-                    let date_time: DateTime<Local> = x.into();
-                    date_time.format(DATE_TIME_FORMAT).to_string()
-                })
-                .unwrap_or_default()
-        })
-        .unwrap_or_default()
-}
-
 /// Returns five empty lines as trailer content if displaying trailer
 /// is not disabled by using `NO_HEADER_TRAILER_OPTION`option.
 fn trailer_content(options: &OutputOptions) -> Vec<String> {

tests/by-util/test_pr.rs

@@ -9,29 +9,33 @@ use std::fs::metadata;
 use uutests::new_ucmd;
 use uutests::util::UCommand;
 
-const DATE_TIME_FORMAT: &str = "%b %d %H:%M %Y";
+const DATE_TIME_FORMAT_DEFAULT: &str = "%Y-%m-%d %H:%M";
 
-fn file_last_modified_time(ucmd: &UCommand, path: &str) -> String {
+fn file_last_modified_time_format(ucmd: &UCommand, path: &str, format: &str) -> String {
     let tmp_dir_path = ucmd.get_full_fixture_path(path);
     let file_metadata = metadata(tmp_dir_path);
     file_metadata
         .map(|i| {
             i.modified()
                 .map(|x| {
                     let date_time: DateTime<Utc> = x.into();
-                    date_time.format(DATE_TIME_FORMAT).to_string()
+                    date_time.format(format).to_string()
                 })
                 .unwrap_or_default()
         })
         .unwrap_or_default()
 }
 
+fn file_last_modified_time(ucmd: &UCommand, path: &str) -> String {
+    file_last_modified_time_format(ucmd, path, DATE_TIME_FORMAT_DEFAULT)
+}
+
 fn all_minutes(from: DateTime<Utc>, to: DateTime<Utc>) -> Vec<String> {
     let to = to + Duration::try_minutes(1).unwrap();
     let mut vec = vec![];
     let mut current = from;
     while current < to {
-        vec.push(current.format(DATE_TIME_FORMAT).to_string());
+        vec.push(current.format(DATE_TIME_FORMAT_DEFAULT).to_string());
         current += Duration::try_minutes(1).unwrap();
     }
     vec
@@ -398,6 +402,94 @@ fn test_with_offset_space_option() {
         .stdout_is_templated_fixture(expected_test_file_path, &[("{last_modified_time}", &value)]);
 }
 
+#[test]
+fn test_with_date_format() {
+    let test_file_path = "test_one_page.log";
+    let expected_test_file_path = "test_one_page.log.expected";
+    let mut scenario = new_ucmd!();
+    let value = file_last_modified_time_format(&scenario, test_file_path, "%Y__%s");
+    scenario
+        .args(&[test_file_path, "-D", "%Y__%s"])
+        .succeeds()
+        .stdout_is_templated_fixture(expected_test_file_path, &[("{last_modified_time}", &value)]);
+
+    // "Format" doesn't need to contain any replaceable token.
+    let mut scenario = new_ucmd!();
+    scenario
+        .args(&[test_file_path, "-D", "Hello!"])
+        .succeeds()
+        .stdout_is_templated_fixture(
+            expected_test_file_path,
+            &[("{last_modified_time}", "Hello!")],
+        );
+
+    // Long option also works
+    let mut scenario = new_ucmd!();
+    scenario
+        .args(&[test_file_path, "--date-format=Hello!"])
+        .succeeds()
+        .stdout_is_templated_fixture(
+            expected_test_file_path,
+            &[("{last_modified_time}", "Hello!")],
+        );
+
+    // Option takes precedence over environment variables
+    let mut scenario = new_ucmd!();
+    scenario
+        .env("POSIXLY_CORRECT", "1")
+        .env("LC_TIME", "POSIX")
+        .args(&[test_file_path, "-D", "Hello!"])
+        .succeeds()
+        .stdout_is_templated_fixture(
+            expected_test_file_path,
+            &[("{last_modified_time}", "Hello!")],
+        );
+}
+
+#[test]
+fn test_with_date_format_env() {
+    const POSIXLY_FORMAT: &str = "%b %e %H:%M %Y";
+
+    // POSIXLY_CORRECT + LC_ALL/TIME=POSIX uses "%b %e %H:%M %Y" date format
+    let test_file_path = "test_one_page.log";
+    let expected_test_file_path = "test_one_page.log.expected";
+    let mut scenario = new_ucmd!();
+    let value = file_last_modified_time_format(&scenario, test_file_path, POSIXLY_FORMAT);
+    scenario
+        .env("POSIXLY_CORRECT", "1")
+        .env("LC_ALL", "POSIX")
+        .args(&[test_file_path])
+        .succeeds()
+        .stdout_is_templated_fixture(expected_test_file_path, &[("{last_modified_time}", &value)]);
+
+    let mut scenario = new_ucmd!();
+    let value = file_last_modified_time_format(&scenario, test_file_path, POSIXLY_FORMAT);
+    scenario
+        .env("POSIXLY_CORRECT", "1")
+        .env("LC_TIME", "POSIX")
+        .args(&[test_file_path])
+        .succeeds()
+        .stdout_is_templated_fixture(expected_test_file_path, &[("{last_modified_time}", &value)]);
+
+    // But not if POSIXLY_CORRECT/LC_ALL is something else.
+    let mut scenario = new_ucmd!();
+    let value = file_last_modified_time_format(&scenario, test_file_path, DATE_TIME_FORMAT_DEFAULT);
+    scenario
+        .env("LC_TIME", "POSIX")
+        .args(&[test_file_path])
+        .succeeds()
+        .stdout_is_templated_fixture(expected_test_file_path, &[("{last_modified_time}", &value)]);
+
+    let mut scenario = new_ucmd!();
+    let value = file_last_modified_time_format(&scenario, test_file_path, DATE_TIME_FORMAT_DEFAULT);
+    scenario
+        .env("POSIXLY_CORRECT", "1")
+        .env("LC_TIME", "C")
+        .args(&[test_file_path])
+        .succeeds()
+        .stdout_is_templated_fixture(expected_test_file_path, &[("{last_modified_time}", &value)]);
+}
+
 #[test]
 fn test_with_pr_core_utils_tests() {
     let test_cases = vec![