kernel_cmdline: Manually impl semantically-correct equivalence for Cmdline

Signed-off-by: John Eckersberg <[email protected]>

Author: jeckersb

crates/kernel_cmdline/src/bytes.rs

@@ -17,7 +17,7 @@ use serde::{Deserialize, Serialize};
 /// Wraps the raw command line bytes and provides methods for parsing and iterating
 /// over individual parameters. Uses copy-on-write semantics to avoid unnecessary
 /// allocations when working with borrowed data.
-#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Clone, Debug, Default, Serialize, Deserialize)]
 pub struct Cmdline<'a>(Cow<'a, [u8]>);
 
 /// An owned Cmdline.  Alias for `Cmdline<'static>`.
@@ -375,6 +375,19 @@ impl<'a, 'other> Extend<Parameter<'other>> for Cmdline<'a> {
     }
 }
 
+impl PartialEq for Cmdline<'_> {
+    fn eq(&self, other: &Self) -> bool {
+        let mut our_params = self.iter().collect::<Vec<_>>();
+        our_params.sort();
+        let mut their_params = other.iter().collect::<Vec<_>>();
+        their_params.sort();
+
+        our_params == their_params
+    }
+}
+
+impl Eq for Cmdline<'_> {}
+
 /// A single kernel command line parameter key
 ///
 /// Handles quoted values and treats dashes and underscores in keys as equivalent.
@@ -1091,4 +1104,24 @@ mod tests {
 
         assert_eq!(params.len(), 0);
     }
+
+    #[test]
+    fn test_cmdline_eq() {
+        // Ordering, quoting, and the whole dash-underscore
+        // equivalence thing shouldn't affect whether these are
+        // semantically equal
+        assert_eq!(
+            Cmdline::from("foo bar-with-delim=\"with spaces\""),
+            Cmdline::from("\"bar_with_delim=with spaces\" foo")
+        );
+
+        // Uneven lengths are not equal even if the parameters are. Or
+        // to put it another way, duplicate parameters break equality.
+        // Check with both orderings.
+        assert_ne!(Cmdline::from("foo"), Cmdline::from("foo foo"));
+        assert_ne!(Cmdline::from("foo foo"), Cmdline::from("foo"));
+
+        // Equal lengths but differing duplicates are also not equal
+        assert_ne!(Cmdline::from("a a b"), Cmdline::from("a b b"));
+    }
 }

crates/kernel_cmdline/src/utf8.rs

@@ -928,4 +928,24 @@ mod tests {
         assert_eq!(params[1], param("baz=qux"));
         assert_eq!(params[2], param("wiz"));
     }
+
+    #[test]
+    fn test_cmdline_eq() {
+        // Ordering, quoting, and the whole dash-underscore
+        // equivalence thing shouldn't affect whether these are
+        // semantically equal
+        assert_eq!(
+            Cmdline::from("foo bar-with-delim=\"with spaces\""),
+            Cmdline::from("\"bar_with_delim=with spaces\" foo")
+        );
+
+        // Uneven lengths are not equal even if the parameters are. Or
+        // to put it another way, duplicate parameters break equality.
+        // Check with both orderings.
+        assert_ne!(Cmdline::from("foo"), Cmdline::from("foo foo"));
+        assert_ne!(Cmdline::from("foo foo"), Cmdline::from("foo"));
+
+        // Equal lengths but differing duplicates are also not equal
+        assert_ne!(Cmdline::from("a a b"), Cmdline::from("a b b"));
+    }
 }