nl: make line number and --join-blank-lines work over multiple files

src/uu/nl/src/nl.rs

@@ -55,6 +55,20 @@ impl Default for Settings {
     }
 }
 
+struct Stats {
+    line_number: i64,
+    consecutive_empty_lines: u64,
+}
+
+impl Stats {
+    fn new(starting_line_number: i64) -> Self {
+        Self {
+            line_number: starting_line_number,
+            consecutive_empty_lines: 0,
+        }
+    }
+}
+
 // NumberingStyle stores which lines are to be numbered.
 // The possible options are:
 // 1. Number all lines
@@ -160,6 +174,8 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         None => vec!["-".to_owned()],
     };
 
+    let mut stats = Stats::new(settings.starting_line_number);
+
     for file in &files {
         if file == "-" {
             // If both file names and '-' are specified, we choose to treat first all
@@ -170,12 +186,12 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         let path = Path::new(file);
         let reader = File::open(path).map_err_context(|| file.to_string())?;
         let mut buffer = BufReader::new(reader);
-        nl(&mut buffer, &settings)?;
+        nl(&mut buffer, &mut stats, &settings)?;
     }
 
     if read_stdin {
         let mut buffer = BufReader::new(stdin());
-        nl(&mut buffer, &settings)?;
+        nl(&mut buffer, &mut stats, &settings)?;
     }
     Ok(())
 }
@@ -285,18 +301,16 @@ pub fn uu_app() -> Command {
 }
 
 // nl implements the main functionality for an individual buffer.
-fn nl<T: Read>(reader: &mut BufReader<T>, settings: &Settings) -> UResult<()> {
+fn nl<T: Read>(reader: &mut BufReader<T>, stats: &mut Stats, settings: &Settings) -> UResult<()> {
     let mut current_numbering_style = &settings.body_numbering;
-    let mut line_no = settings.starting_line_number;
-    let mut consecutive_empty_lines = 0;
 
     for line in reader.lines() {
         let line = line.map_err_context(|| "could not read line".to_string())?;
 
         if line.is_empty() {
-            consecutive_empty_lines += 1;
+            stats.consecutive_empty_lines += 1;
         } else {
-            consecutive_empty_lines = 0;
+            stats.consecutive_empty_lines = 0;
         };
 
         // FIXME section delimiters are hardcoded and settings.section_delimiter is ignored
@@ -312,7 +326,7 @@ fn nl<T: Read>(reader: &mut BufReader<T>, settings: &Settings) -> UResult<()> {
         if let Some(new_style) = new_numbering_style {
             current_numbering_style = new_style;
             if settings.renumber {
-                line_no = settings.starting_line_number;
+                stats.line_number = settings.starting_line_number;
             }
             println!();
         } else {
@@ -321,7 +335,7 @@ fn nl<T: Read>(reader: &mut BufReader<T>, settings: &Settings) -> UResult<()> {
                 // for numbering, and only number the last one
                 NumberingStyle::All
                     if line.is_empty()
-                        && consecutive_empty_lines % settings.join_blank_lines != 0 =>
+                        && stats.consecutive_empty_lines % settings.join_blank_lines != 0 =>
                 {
                     false
                 }
@@ -336,13 +350,13 @@ fn nl<T: Read>(reader: &mut BufReader<T>, settings: &Settings) -> UResult<()> {
                     "{}{}{}",
                     settings
                         .number_format
-                        .format(line_no, settings.number_width),
+                        .format(stats.line_number, settings.number_width),
                     settings.number_separator,
                     line
                 );
                 // update line number for the potential next line
-                match line_no.checked_add(settings.line_increment) {
-                    Some(new_line_no) => line_no = new_line_no,
+                match stats.line_number.checked_add(settings.line_increment) {
+                    Some(new_line_number) => stats.line_number = new_line_number,
                     None => return Err(USimpleError::new(1, "line number overflow")),
                 }
             } else {

tests/by-util/test_nl.rs

@@ -284,6 +284,31 @@ fn test_join_blank_lines() {
     }
 }
 
+#[test]
+fn test_join_blank_lines_multiple_files() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    at.write("a.txt", "\n\n");
+    at.write("b.txt", "\n\n");
+    at.write("c.txt", "\n\n");
+
+    for arg in ["-l3", "--join-blank-lines=3"] {
+        scene
+            .ucmd()
+            .args(&[arg, "--body-numbering=a", "a.txt", "b.txt", "c.txt"])
+            .succeeds()
+            .stdout_is(concat!(
+                "       \n",
+                "       \n",
+                "     1\t\n",
+                "       \n",
+                "       \n",
+                "     2\t\n",
+            ));
+    }
+}
+
 #[test]
 fn test_join_blank_lines_zero() {
     for arg in ["-l0", "--join-blank-lines=0"] {
@@ -311,6 +336,19 @@ fn test_default_body_numbering() {
         .stdout_is("     1\ta\n       \n     2\tb\n");
 }
 
+#[test]
+fn test_default_body_numbering_multiple_files() {
+    let (at, mut ucmd) = at_and_ucmd!();
+
+    at.write("a.txt", "a");
+    at.write("b.txt", "b");
+    at.write("c.txt", "c");
+
+    ucmd.args(&["a.txt", "b.txt", "c.txt"])
+        .succeeds()
+        .stdout_is("     1\ta\n     2\tb\n     3\tc\n");
+}
+
 #[test]
 fn test_body_numbering_all_lines_without_delimiter() {
     for arg in ["-ba", "--body-numbering=a"] {