cksum/hashsum: try to detect the format faster the first line

src/uucore/src/lib/features/checksum.rs

@@ -310,6 +310,32 @@ const DOUBLE_SPACE_REGEX: &str = r"^(?P<checksum>[a-fA-F0-9]+)\s{2}(?P<filename>
 // In this case, we ignore the *
 const SINGLE_SPACE_REGEX: &str = r"^(?P<checksum>[a-fA-F0-9]+)\s(?P<binary>\*?)(?P<filename>.*)$";
 
+/// Determines the appropriate regular expression to use based on the provided lines.
+fn determine_regex(filename: &OsStr, lines: &[String]) -> UResult<(Regex, bool)> {
+    let algo_based_regex = Regex::new(ALGO_BASED_REGEX).unwrap();
+    let double_space_regex = Regex::new(DOUBLE_SPACE_REGEX).unwrap();
+    let single_space_regex = Regex::new(SINGLE_SPACE_REGEX).unwrap();
+
+    for line in lines {
+        let line_trim = line.trim();
+        if algo_based_regex.is_match(line_trim) {
+            return Ok((algo_based_regex, true));
+        } else if double_space_regex.is_match(line_trim) {
+            return Ok((double_space_regex, false));
+        } else if single_space_regex.is_match(line_trim) {
+            return Ok((single_space_regex, false));
+        }
+    }
+
+    Err(io::Error::new(
+        io::ErrorKind::InvalidData,
+        format!(
+            "{}: no properly formatted checksum lines found",
+            filename.maybe_quote()
+        ),
+    )
+    .into())
+}
 /***
  * Do the checksum validation (can be strict or not)
 */
@@ -328,10 +354,6 @@ pub fn perform_checksum_validation<'a, I>(
 where
     I: Iterator<Item = &'a OsStr>,
 {
-    let algo_based_regex = Regex::new(ALGO_BASED_REGEX).unwrap();
-    let double_space_regex = Regex::new(DOUBLE_SPACE_REGEX).unwrap();
-    let single_space_regex = Regex::new(SINGLE_SPACE_REGEX).unwrap();
-
     // if cksum has several input files, it will print the result for each file
     for filename_input in files {
         let mut bad_format = 0;
@@ -358,31 +380,13 @@ where
                 }
             }
         };
-        let mut reader = BufReader::new(file);
-
-        let mut first_line = String::new();
-        reader.read_line(&mut first_line)?;
-
-        // Determine which regular expression to use based on the first line
-        let first_line_trim = first_line.trim();
-        let (chosen_regex, algo_based_format) = if algo_based_regex.is_match(first_line_trim) {
-            (&algo_based_regex, true)
-        } else if double_space_regex.is_match(first_line_trim) {
-            // If the first line contains a double space, use the double space regex
-            (&double_space_regex, false)
-        } else {
-            // It is probably rare but sometimes the checksum file may contain a single space
-            (&single_space_regex, false)
-        };
 
-        // Push the first line back to the reader
-        let first_line_reader = io::Cursor::new(first_line);
-        let chain_reader = first_line_reader.chain(reader);
-        let reader = BufReader::new(chain_reader);
+        let reader = BufReader::new(file);
+        let lines: Vec<String> = reader.lines().collect::<Result<_, _>>()?;
+        let (chosen_regex, algo_based_format) = determine_regex(filename_input, &lines)?;
 
-        // for each line in the input, check if it is a valid checksum line
-        for (i, line) in reader.lines().enumerate() {
-            let line = line.unwrap_or_else(|_| String::new());
+        // Process each line
+        for (i, line) in lines.iter().enumerate() {
             if let Some(caps) = chosen_regex.captures(&line) {
                 properly_formatted = true;
 
@@ -886,4 +890,49 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn test_determine_regex() {
+        // Test algo-based regex
+        let lines_algo_based =
+            vec!["MD5 (example.txt) = d41d8cd98f00b204e9800998ecf8427e".to_string()];
+        let result = determine_regex(&lines_algo_based);
+        assert!(result.is_ok());
+        let (regex, algo_based) = result.unwrap();
+        assert!(algo_based);
+        assert!(regex.is_match(&lines_algo_based[0]));
+
+        // Test double-space regex
+        let lines_double_space = vec!["d41d8cd98f00b204e9800998ecf8427e  example.txt".to_string()];
+        let result = determine_regex(&lines_double_space);
+        assert!(result.is_ok());
+        let (regex, algo_based) = result.unwrap();
+        assert!(!algo_based);
+        assert!(regex.is_match(&lines_double_space[0]));
+
+        // Test single-space regex
+        let lines_single_space = vec!["d41d8cd98f00b204e9800998ecf8427e example.txt".to_string()];
+        let result = determine_regex(&lines_single_space);
+        assert!(result.is_ok());
+        let (regex, algo_based) = result.unwrap();
+        assert!(!algo_based);
+        assert!(regex.is_match(&lines_single_space[0]));
+
+        // Test double-space regex start with invalid
+        let lines_double_space = vec![
+            "ERR".to_string(),
+            "d41d8cd98f00b204e9800998ecf8427e  example.txt".to_string(),
+        ];
+        let result = determine_regex(&lines_double_space);
+        assert!(result.is_ok());
+        let (regex, algo_based) = result.unwrap();
+        assert!(!algo_based);
+        assert!(!regex.is_match(&lines_double_space[0]));
+        assert!(regex.is_match(&lines_double_space[1]));
+
+        // Test invalid checksum line
+        let lines_invalid = vec!["invalid checksum line".to_string()];
+        let result = determine_regex(&lines_invalid);
+        assert!(result.is_err());
+    }
 }

tests/by-util/test_hashsum.rs

@@ -724,62 +724,90 @@ fn test_check_one_two_space_star() {
 }
 
 #[test]
-fn test_check_one_two_space_star_start_without_star() {
+fn test_check_space_star_or_not() {
     let scene = TestScenario::new(util_name!());
     let at = &scene.fixtures;
 
-    at.touch("empty");
-    at.touch("f");
+    at.touch("a");
+    at.touch("*c");
 
     // with one space, the "*" is removed
     at.write(
         "in.md5",
-        "d41d8cd98f00b204e9800998ecf8427e f\nd41d8cd98f00b204e9800998ecf8427e *empty\n",
+        "d41d8cd98f00b204e9800998ecf8427e *c\n
+        d41d8cd98f00b204e9800998ecf8427e a\n",
     );
 
     scene
         .ccmd("md5sum")
         .arg("--check")
         .arg(at.subdir.join("in.md5"))
-        .succeeds()
-        .stdout_is("f: OK\nempty: OK\n");
+        .fails()
+        .stdout_contains("c: FAILED")
+        .stdout_does_not_contain("a: FAILED")
+        .stderr_contains("WARNING: 1 line is improperly formatted");
 
-    // with two spaces, the "*" is not removed
     at.write(
         "in.md5",
-        "d41d8cd98f00b204e9800998ecf8427e  f\nd41d8cd98f00b204e9800998ecf8427e  *empty\n",
+        "d41d8cd98f00b204e9800998ecf8427e a\n
+            d41d8cd98f00b204e9800998ecf8427e *c\n",
     );
+
     // First should fail as *empty doesn't exit
     scene
         .ccmd("md5sum")
         .arg("--check")
         .arg(at.subdir.join("in.md5"))
         .fails()
-        .stdout_is("f: OK\n*empty: FAILED open or read\n");
+        .stdout_contains("a: FAILED")
+        .stdout_contains("*c: FAILED");
+}
 
-    at.touch("*empty");
-    // Should pass as we have the file
+#[test]
+fn test_check_no_backslash_no_space() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    at.touch("f");
+    at.write("in.md5", "MD5(f)= d41d8cd98f00b204e9800998ecf8427e\n");
     scene
         .ccmd("md5sum")
         .arg("--check")
         .arg(at.subdir.join("in.md5"))
         .succeeds()
-        .stdout_is("f: OK\n*empty: OK\n");
+        .stdout_is("f: OK\n");
 }
 
 #[test]
-fn test_check_no_backslash_no_space() {
+fn test_incomplete_format() {
     let scene = TestScenario::new(util_name!());
     let at = &scene.fixtures;
 
     at.touch("f");
-    at.write("in.md5", "MD5(f)= d41d8cd98f00b204e9800998ecf8427e\n");
+    at.write("in.md5", "MD5 (\n");
     scene
         .ccmd("md5sum")
         .arg("--check")
         .arg(at.subdir.join("in.md5"))
-        .succeeds()
-        .stdout_is("f: OK\n");
+        .fails()
+        .stderr_contains("no properly formatted checksum lines found");
+}
+
+#[test]
+fn test_start_error() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    at.touch("f");
+    at.write("in.md5", "ERR\nd41d8cd98f00b204e9800998ecf8427e  f\n");
+    scene
+        .ccmd("md5sum")
+        .arg("--check")
+        .arg("--strict")
+        .arg(at.subdir.join("in.md5"))
+        .fails()
+        .stdout_is("f: OK\n")
+        .stderr_contains("WARNING: 1 line is improperly formatted");
 }
 
 #[test]