index: define methods from CompositeIndex directly on {Readonly,Mutable}Index

This is one step towards making `CompositeIndex` non-public (and maybe
deleting it). Next, we'll add an `IndexRef` enum similar to `RepoRef`
etc.

lib/src/index.rs

@@ -143,15 +143,10 @@ fn topo_order_parents_first(
     let mut commits = vec![];
     let mut visited = HashSet::new();
     let mut in_parent_file = HashSet::new();
-    let parent_file_source = parent_file
-        .as_ref()
-        .map(|file| file.as_ref().as_composite());
+    let parent_file_source = parent_file.as_ref().map(|file| file.as_ref());
     while !work.is_empty() {
         let commit = work.pop().unwrap();
-        if parent_file_source
-            .as_ref()
-            .map_or(false, |index| index.has_id(commit.id()))
-        {
+        if parent_file_source.map_or(false, |index| index.has_id(commit.id())) {
             in_parent_file.insert(commit.id().clone());
             continue;
         } else if !visited.insert(commit.id().clone()) {
@@ -306,7 +301,6 @@ impl MutableIndex {
         };
         for parent_id in parent_ids {
             let parent_entry = self
-                .as_composite()
                 .entry_by_id(&parent_id)
                 .expect("parent commit is not indexed");
             entry.generation_number = max(
@@ -378,6 +372,45 @@ impl MutableIndex {
 
         buf
     }
+
+    pub fn num_commits(&self) -> u32 {
+        CompositeIndex(self).num_commits()
+    }
+
+    pub fn stats(&self) -> IndexStats {
+        CompositeIndex(self).stats()
+    }
+
+    pub fn commit_id_to_pos(&self, commit_id: &CommitId) -> Option<u32> {
+        CompositeIndex(self).commit_id_to_pos(commit_id)
+    }
+
+    pub fn resolve_prefix(&self, prefix: &HexPrefix) -> PrefixResolution {
+        CompositeIndex(self).resolve_prefix(prefix)
+    }
+
+    pub fn entry_by_id(&self, commit_id: &CommitId) -> Option<IndexEntry> {
+        CompositeIndex(self).entry_by_id(commit_id)
+    }
+
+    pub fn has_id(&self, commit_id: &CommitId) -> bool {
+        CompositeIndex(self).has_id(commit_id)
+    }
+
+    pub fn is_ancestor(&self, ancestor_id: &CommitId, descendant_id: &CommitId) -> bool {
+        CompositeIndex(self).is_ancestor(ancestor_id, descendant_id)
+    }
+
+    pub fn walk_revs(&self, wanted: &[CommitId], unwanted: &[CommitId]) -> RevWalk {
+        CompositeIndex(self).walk_revs(wanted, unwanted)
+    }
+
+    pub fn heads<'candidates>(
+        &self,
+        candidates: impl IntoIterator<Item = &'candidates CommitId>,
+    ) -> Vec<CommitId> {
+        CompositeIndex(self).heads(candidates)
+    }
 }
 
 trait IndexSegment {
@@ -489,7 +522,7 @@ impl<'a> CompositeIndex<'a> {
             .segment_parent_file()
             .as_ref()
             .map_or(PrefixResolution::NoMatch, |file| {
-                file.as_composite().resolve_prefix(prefix)
+                file.resolve_prefix(prefix)
             });
         local_match.plus(&parent_match)
     }
@@ -530,7 +563,7 @@ impl<'a> CompositeIndex<'a> {
         false
     }
 
-    pub fn walk_revs(&self, wanted: &[CommitId], unwanted: &[CommitId]) -> RevWalk {
+    pub fn walk_revs(&self, wanted: &[CommitId], unwanted: &[CommitId]) -> RevWalk<'a> {
         let mut rev_walk = RevWalk::new(self.clone());
         for pos in wanted.iter().map(|id| self.commit_id_to_pos(id).unwrap()) {
             rev_walk.add_wanted(pos);
@@ -1077,6 +1110,45 @@ impl ReadonlyIndex {
         CompositeIndex(self)
     }
 
+    pub fn num_commits(&self) -> u32 {
+        CompositeIndex(self).num_commits()
+    }
+
+    pub fn stats(&self) -> IndexStats {
+        CompositeIndex(self).stats()
+    }
+
+    pub fn commit_id_to_pos(&self, commit_id: &CommitId) -> Option<u32> {
+        CompositeIndex(self).commit_id_to_pos(commit_id)
+    }
+
+    pub fn resolve_prefix(&self, prefix: &HexPrefix) -> PrefixResolution {
+        CompositeIndex(self).resolve_prefix(prefix)
+    }
+
+    pub fn entry_by_id(&self, commit_id: &CommitId) -> Option<IndexEntry> {
+        CompositeIndex(self).entry_by_id(commit_id)
+    }
+
+    pub fn has_id(&self, commit_id: &CommitId) -> bool {
+        CompositeIndex(self).has_id(commit_id)
+    }
+
+    pub fn is_ancestor(&self, ancestor_id: &CommitId, descendant_id: &CommitId) -> bool {
+        CompositeIndex(self).is_ancestor(ancestor_id, descendant_id)
+    }
+
+    pub fn walk_revs(&self, wanted: &[CommitId], unwanted: &[CommitId]) -> RevWalk {
+        CompositeIndex(self).walk_revs(wanted, unwanted)
+    }
+
+    pub fn heads<'candidates>(
+        &self,
+        candidates: impl IntoIterator<Item = &'candidates CommitId>,
+    ) -> Vec<CommitId> {
+        CompositeIndex(self).heads(candidates)
+    }
+
     fn graph_entry(&self, local_pos: u32) -> CommitGraphEntry {
         let offset = (local_pos as usize) * self.commit_graph_entry_size;
         CommitGraphEntry {

src/commands.rs

@@ -104,8 +104,7 @@ fn resolve_commit_id_prefix(
     repo: &ReadonlyRepo,
     prefix: &HexPrefix,
 ) -> Result<CommitId, CommandError> {
-    let index = repo.index();
-    match index.as_composite().resolve_prefix(prefix) {
+    match repo.index().resolve_prefix(prefix) {
         PrefixResolution::NoMatch => Err(CommandError::UserError(String::from("No such commit"))),
         PrefixResolution::AmbiguousMatch => {
             Err(CommandError::UserError(String::from("Ambiguous prefix")))
@@ -1767,8 +1766,7 @@ fn cmd_debug(
         writeln!(ui, "{:?}", parse);
     } else if let Some(_reindex_matches) = sub_matches.subcommand_matches("index") {
         let repo = get_repo(ui, &matches)?;
-        let index = repo.index();
-        let stats = index.as_composite().stats();
+        let stats = repo.index().stats();
         writeln!(ui, "Number of commits: {}", stats.num_commits);
         writeln!(ui, "Number of merges: {}", stats.num_merges);
         writeln!(ui, "Max generation number: {}", stats.max_generation_number);
@@ -1783,11 +1781,7 @@ fn cmd_debug(
         let mut repo = get_repo(ui, &matches)?;
         let mut_repo = Arc::get_mut(&mut repo).unwrap();
         let index = mut_repo.reindex();
-        writeln!(
-            ui,
-            "Finished indexing {:?} commits.",
-            index.as_composite().num_commits()
-        );
+        writeln!(ui, "Finished indexing {:?} commits.", index.num_commits());
     } else {
         panic!("unhandled command: {:#?}", matches);
     }
@@ -1823,7 +1817,6 @@ fn cmd_bench(
             command_matches.value_of("descendant").unwrap(),
         )?;
         let index = repo.index();
-        let index = index.as_composite();
         let routine = || index.is_ancestor(ancestor_commit.id(), descendant_commit.id());
         writeln!(ui, "Result: {:?}", routine());
         criterion.bench_function("isancestor", |bencher: &mut criterion::Bencher| {
@@ -1837,7 +1830,6 @@ fn cmd_bench(
         let wanted_commit =
             resolve_single_rev(ui, mut_repo, command_matches.value_of("wanted").unwrap())?;
         let index = repo.index();
-        let index = index.as_composite();
         let routine = || {
             index
                 .walk_revs(
@@ -1854,7 +1846,6 @@ fn cmd_bench(
         let repo = get_repo(ui, &matches)?;
         let prefix = HexPrefix::new(command_matches.value_of("prefix").unwrap().to_string());
         let index = repo.index();
-        let index = index.as_composite();
         let routine = || index.resolve_prefix(&prefix);
         writeln!(ui, "Result: {:?}", routine());
         criterion.bench_function("resolveprefix", |bencher: &mut criterion::Bencher| {