simplify

relay-event-normalization/src/normalize/span/description/redis.rs

@@ -1,26 +1,25 @@
-use std::cmp::Ordering;
-
 /// Returns a redis command if it is a case-insensitive prefix of `seek`.
-pub fn matching_redis_command(seek: &str) -> Option<&str> {
-    let seek = seek.as_bytes();
-    let index = REDIS_COMMANDS
-        .binary_search_by(|probe| {
-            let probe = probe.as_bytes();
-            // step 1 - compare prefixes
-            for (probe, seek) in probe.iter().zip(seek) {
-                match probe.to_ascii_lowercase().cmp(&seek.to_ascii_lowercase()) {
-                    Ordering::Equal => continue,
-                    neq => return neq,
-                };
-            }
-            // step 2 - compare length
-            match probe.len().cmp(&seek.len()) {
-                Ordering::Greater => Ordering::Greater,
-                _ => Ordering::Equal,
+pub fn matching_redis_command(needle: &str) -> Option<&str> {
+    let mut longest_match = None;
+    for command in REDIS_COMMANDS {
+        if command.len() > longest_match.map_or(0, str::len) {
+            if is_ascii_prefix_lowercase(command, needle) {
+                // needle must be either the same length as command OR continue with a non-word
+                let next_needle_byte = needle.as_bytes().get(command.len()).unwrap_or(&b' ');
+                if next_needle_byte.is_ascii_whitespace() {
+                    longest_match.replace(command);
+                }
             }
-        })
-        .ok()?;
-    Some(REDIS_COMMANDS[index])
+        }
+    }
+    longest_match
+}
+
+fn is_ascii_prefix_lowercase(a: &str, b: &str) -> bool {
+    (a.len() <= b.len())
+        && a.chars()
+            .zip(b.chars())
+            .all(|(a, b)| a.to_ascii_lowercase() == b.to_ascii_lowercase())
 }
 
 /// List of redis commands.
@@ -588,4 +587,24 @@ mod tests {
     fn empty_needle() {
         assert_eq!(matching_redis_command(""), None);
     }
+
+    #[test]
+    fn ambiguous1() {
+        assert_eq!(matching_redis_command("ACL"), Some("ACL"));
+    }
+
+    #[test]
+    fn ambiguous2() {
+        assert_eq!(matching_redis_command("ACL CAT"), Some("ACL CAT"));
+    }
+
+    #[test]
+    fn non_word_boundary() {
+        assert_eq!(matching_redis_command("ACL cattington"), Some("ACL"));
+    }
+
+    #[test]
+    fn non_ascii() {
+        assert_eq!(matching_redis_command("ACL catø"), Some("ACL"));
+    }
 }