From 715f87450eeed237aeb42cedd325bd2f7d67d8fd Mon Sep 17 00:00:00 2001
From: Jack O'Connor <oconnor663@gmail.com>
Date: Fri, 28 Feb 2025 17:32:37 -0800
Subject: use rsplit_once for parsing tagged lines, add test cases

---
 b3sum/src/main.rs       |  6 +++++-
 b3sum/src/unit_tests.rs | 30 ++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/b3sum/src/main.rs b/b3sum/src/main.rs
index 2d0ba5d..4479d4d 100644
--- a/b3sum/src/main.rs
+++ b/b3sum/src/main.rs
@@ -335,15 +335,19 @@ struct ParsedCheckLine {
 }
 
 fn split_untagged_check_line(line_after_slash: &str) -> Option<(&str, &str)> {
+    // Of the form "<hash>  <file>". The file might contain "  ", so we need to split from the
+    // left.
     line_after_slash.split_once("  ")
 }
 
 fn split_tagged_check_line(line_after_slash: &str) -> Option<(&str, &str)> {
+    // Of the form "BLAKE3 (<file>) = <hash>". The file might contain ") = ", so we need to split
+    // from the *right*.
     let prefix = "BLAKE3 (";
     if !line_after_slash.starts_with(prefix) {
         return None;
     }
-    line_after_slash[prefix.len()..].split_once(") = ")
+    line_after_slash[prefix.len()..].rsplit_once(") = ")
 }
 
 fn parse_check_line(mut line: &str) -> anyhow::Result<ParsedCheckLine> {
diff --git a/b3sum/src/unit_tests.rs b/b3sum/src/unit_tests.rs
index b95c4a2..75f672b 100644
--- a/b3sum/src/unit_tests.rs
+++ b/b3sum/src/unit_tests.rs
@@ -119,6 +119,36 @@ fn test_parse_check_line() {
     assert_eq!(file_string, "否认");
     assert_eq!(file_path, Path::new("否认"));
 
+    // untagged separator "  " in the file name
+    let crate::ParsedCheckLine {
+        file_string,
+        is_escaped,
+        file_path,
+        expected_hash,
+    } = crate::parse_check_line(
+        "4747474747474747474747474747474747474747474747474747474747474747  foo  bar",
+    )
+    .unwrap();
+    assert_eq!(expected_hash, blake3::Hash::from([0x47; 32]));
+    assert!(!is_escaped);
+    assert_eq!(file_string, "foo  bar");
+    assert_eq!(file_path, Path::new("foo  bar"));
+
+    // tagged separator ") = " in the file name
+    let crate::ParsedCheckLine {
+        file_string,
+        is_escaped,
+        file_path,
+        expected_hash,
+    } = crate::parse_check_line(
+        "BLAKE3 (foo) = bar) = 4848484848484848484848484848484848484848484848484848484848484848",
+    )
+    .unwrap();
+    assert_eq!(expected_hash, blake3::Hash::from([0x48; 32]));
+    assert!(!is_escaped);
+    assert_eq!(file_string, "foo) = bar");
+    assert_eq!(file_path, Path::new("foo) = bar"));
+
     // =========================
     // ===== Failure Cases =====
     // =========================
-- 
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