files: relax requirement of merge() inputs

Most callers have Merge<ContentHunk> or Merge<Vec<u8>>.

cli/src/merge_tools/builtin.rs

@@ -601,8 +601,7 @@ pub fn edit_merge_builtin(
     path: &RepoPath,
     content: Merge<ContentHunk>,
 ) -> Result<MergedTreeId, BuiltinToolError> {
-    let slices = content.map(|ContentHunk(v)| v.as_slice());
+    let merge_result = files::merge(&content);
-    let merge_result = files::merge(&slices);
     let sections = make_merge_sections(merge_result)?;
     let mut input = scm_record::helpers::CrosstermInput;
     let recorder = scm_record::Recorder::new(
@@ -1014,8 +1013,7 @@ mod tests {
         let content = extract_as_single_hunk(&merge, store, path)
             .block_on()
             .unwrap();
-        let slices = content.map(|ContentHunk(buf)| buf.as_slice());
+        let merge_result = files::merge(&content);
-        let merge_result = files::merge(&slices);
         let sections = make_merge_sections(merge_result).unwrap();
         insta::assert_debug_snapshot!(sections, @r###"
         [

lib/src/conflicts.rs

@@ -219,8 +219,7 @@ pub fn materialize_merge_result(
     single_hunk: &Merge<ContentHunk>,
     output: &mut dyn Write,
 ) -> std::io::Result<()> {
-    let slices = single_hunk.map(|content| content.0.as_slice());
+    let merge_result = files::merge(single_hunk);
-    let merge_result = files::merge(&slices);
     match merge_result {
         MergeResult::Resolved(content) => {
             output.write_all(&content.0)?;

lib/src/files.rs

@@ -141,9 +141,16 @@ impl<'a> Iterator for DiffLineIterator<'a> {
     }
 }
 
+// TODO: Maybe ContentHunk can be replaced with BString?
 #[derive(PartialEq, Eq, Clone)]
 pub struct ContentHunk(pub Vec<u8>);
 
+impl AsRef<[u8]> for ContentHunk {
+    fn as_ref(&self) -> &[u8] {
+        self.0.as_ref()
+    }
+}
+
 impl Debug for ContentHunk {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
         String::from_utf8_lossy(&self.0).fmt(f)
@@ -156,7 +163,7 @@ pub enum MergeResult {
     Conflict(Vec<Merge<ContentHunk>>),
 }
 
-pub fn merge(slices: &Merge<&[u8]>) -> MergeResult {
+pub fn merge<T: AsRef<[u8]>>(slices: &Merge<T>) -> MergeResult {
     // TODO: Using the first remove as base (first in the inputs) is how it's
     // usually done for 3-way conflicts. Are there better heuristics when there are
     // more than 3 parts?
@@ -213,7 +220,7 @@ mod tests {
     }
 
     fn merge(removes: &[&[u8]], adds: &[&[u8]]) -> MergeResult {
-        super::merge(&Merge::from_removes_adds(removes.to_vec(), adds.to_vec()))
+        super::merge(&Merge::from_removes_adds(removes, adds))
     }
 
     #[test]

lib/src/tree.rs

@@ -454,8 +454,7 @@ pub fn try_resolve_file_conflict(
                 })?;
             Ok(content)
         })?;
-    let slices = contents.map(|content| content.as_slice());
+    let merge_result = files::merge(&contents);
-    let merge_result = files::merge(&slices);
     match merge_result {
         MergeResult::Resolved(merged_content) => {
             let id = store.write_file(filename, &mut merged_content.0.as_slice())?;