undo sort_key() returning Cow

src/table/data.rs

@@ -347,7 +347,7 @@ impl<F: TableSchema, R: TableReplication> TableData<F, R> {
 	// ---- Utility functions ----
 
 	pub fn tree_key(&self, p: &F::P, s: &F::S) -> Vec<u8> {
-		[p.hash().as_slice(), s.sort_key().as_ref()].concat()
+		[p.hash().as_slice(), s.sort_key()].concat()
 	}
 
 	pub fn decode_entry(&self, bytes: &[u8]) -> Result<F::E, Error> {

src/table/schema.rs

@@ -1,5 +1,3 @@
-use std::borrow::Cow;
-
 use serde::{Deserialize, Serialize};
 
 use garage_db as db;
@@ -38,24 +36,18 @@ impl PartitionKey for FixedBytes32 {
 /// Trait for field used to sort data
 pub trait SortKey: Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync + 'static {
 	/// Get the key used to sort
-	fn sort_key(&self) -> Cow<'_, [u8]>;
+	fn sort_key(&self) -> &[u8];
 }
 
 impl SortKey for String {
-	fn sort_key(&self) -> Cow<'_, [u8]> {
-		Cow::from(self.as_bytes())
+	fn sort_key(&self) -> &[u8] {
+		self.as_bytes()
 	}
 }
 
 impl SortKey for FixedBytes32 {
-	fn sort_key(&self) -> Cow<'_, [u8]> {
-		Cow::from(self.as_slice())
-	}
-}
-
-impl SortKey for u32 {
-	fn sort_key(&self) -> Cow<'_, [u8]> {
-		Cow::from(u32::to_be_bytes(*self).to_vec())
+	fn sort_key(&self) -> &[u8] {
+		self.as_slice()
 	}
 }
 

src/table/util.rs

@@ -1,5 +1,3 @@
-use std::borrow::Cow;
-
 use serde::{Deserialize, Serialize};
 
 use garage_util::data::*;
@@ -9,8 +7,8 @@ use crate::schema::*;
 #[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct EmptyKey;
 impl SortKey for EmptyKey {
-	fn sort_key(&self) -> Cow<'_, [u8]> {
-		Cow::from(&[][..])
+	fn sort_key(&self) -> &[u8] {
+		&[]
 	}
 }
 impl PartitionKey for EmptyKey {