merge: relax input type of Merge::from_removes_adds()

lib/src/files.rs

@@ -193,12 +193,10 @@ pub fn merge(slices: &Merge<&[u8]>) -> MergeResult {
                     merge_hunks.push(Merge::from_removes_adds(
                         parts[..num_diffs]
                             .iter()
-                            .map(|part| ContentHunk(part.to_vec()))
-                            .collect_vec(),
+                            .map(|part| ContentHunk(part.to_vec())),
                         parts[num_diffs..]
                             .iter()
-                            .map(|part| ContentHunk(part.to_vec()))
-                            .collect_vec(),
+                            .map(|part| ContentHunk(part.to_vec())),
                     ));
                 }
             }

lib/src/merge.rs

@@ -144,10 +144,18 @@ impl<T> Merge<T> {
     }
 
     /// Creates a new merge object from the given removes and adds.
-    pub fn from_removes_adds(removes: Vec<T>, adds: Vec<T>) -> Self {
-        // TODO: removes and adds can be just IntoIterator.
-        assert_eq!(adds.len(), removes.len() + 1);
-        let values = itertools::interleave(adds, removes).collect();
+    pub fn from_removes_adds(
+        removes: impl IntoIterator<Item = T>,
+        adds: impl IntoIterator<Item = T>,
+    ) -> Self {
+        let removes = removes.into_iter();
+        let mut adds = adds.into_iter();
+        let mut values = SmallVec::with_capacity(removes.size_hint().0 * 2 + 1);
+        values.push(adds.next().expect("must have at least one add"));
+        for diff in removes.zip_longest(adds) {
+            let (remove, add) = diff.both().expect("must have one more adds than removes");
+            values.extend([remove, add]);
+        }
         Merge { values }
     }
 

lib/src/simple_op_store.rs

@@ -505,8 +505,8 @@ fn ref_target_from_proto(maybe_proto: Option<crate::protos::op_store::RefTarget>
         crate::protos::op_store::ref_target::Value::Conflict(conflict) => {
             let term_from_proto =
                 |term: crate::protos::op_store::ref_conflict::Term| term.value.map(CommitId::new);
-            let removes = conflict.removes.into_iter().map(term_from_proto).collect();
-            let adds = conflict.adds.into_iter().map(term_from_proto).collect();
+            let removes = conflict.removes.into_iter().map(term_from_proto);
+            let adds = conflict.adds.into_iter().map(term_from_proto);
             RefTarget::from_merge(Merge::from_removes_adds(removes, adds))
         }
     }