Merge pull request #588 from erizocosmico/perf/revlist-norevisit-ancestors-fixed

revlist: do not revisit ancestors as long as all branches are visited

1 files changed, 27 insertions, 3 deletions

diff --git a/plumbing/revlist/revlist.go b/plumbing/revlist/revlist.go
index 009fc93..0a9d1e8 100644
--- a/plumbing/revlist/revlist.go
+++ b/plumbing/revlist/revlist.go
@@ -37,6 +37,7 @@ func objects(
 ) ([]plumbing.Hash, error) {
 	seen := hashListToSet(ignore)
 	result := make(map[plumbing.Hash]bool)
+	visited := make(map[plumbing.Hash]bool)
 
 	walkerFunc := func(h plumbing.Hash) {
 		if !seen[h] {
@@ -46,7 +47,7 @@ func objects(
 	}
 
 	for _, h := range objects {
-		if err := processObject(s, h, seen, ignore, walkerFunc); err != nil {
+		if err := processObject(s, h, seen, visited, ignore, walkerFunc); err != nil {
 			if allowMissingObjects && err == plumbing.ErrObjectNotFound {
 				continue
 			}
@@ -63,6 +64,7 @@ func processObject(
 	s storer.EncodedObjectStorer,
 	h plumbing.Hash,
 	seen map[plumbing.Hash]bool,
+	visited map[plumbing.Hash]bool,
 	ignore []plumbing.Hash,
 	walkerFunc func(h plumbing.Hash),
 ) error {
@@ -82,12 +84,12 @@ func processObject(
 
 	switch do := do.(type) {
 	case *object.Commit:
-		return reachableObjects(do, seen, ignore, walkerFunc)
+		return reachableObjects(do, seen, visited, ignore, walkerFunc)
 	case *object.Tree:
 		return iterateCommitTrees(seen, do, walkerFunc)
 	case *object.Tag:
 		walkerFunc(do.Hash)
-		return processObject(s, do.Target, seen, ignore, walkerFunc)
+		return processObject(s, do.Target, seen, visited, ignore, walkerFunc)
 	case *object.Blob:
 		walkerFunc(do.Hash)
 	default:
@@ -105,10 +107,14 @@ func processObject(
 func reachableObjects(
 	commit *object.Commit,
 	seen map[plumbing.Hash]bool,
+	visited map[plumbing.Hash]bool,
 	ignore []plumbing.Hash,
 	cb func(h plumbing.Hash),
 ) error {
 	i := object.NewCommitPreorderIter(commit, seen, ignore)
+	pending := make(map[plumbing.Hash]bool)
+	addPendingParents(pending, visited, commit)
+
 	for {
 		commit, err := i.Next()
 		if err == io.EOF {
@@ -119,6 +125,16 @@ func reachableObjects(
 			return err
 		}
 
+		if pending[commit.Hash] {
+			delete(pending, commit.Hash)
+		}
+
+		addPendingParents(pending, visited, commit)
+
+		if visited[commit.Hash] && len(pending) == 0 {
+			break
+		}
+
 		if seen[commit.Hash] {
 			continue
 		}
@@ -138,6 +154,14 @@ func reachableObjects(
 	return nil
 }
 
+func addPendingParents(pending, visited map[plumbing.Hash]bool, commit *object.Commit) {
+	for _, p := range commit.ParentHashes {
+		if !visited[p] {
+			pending[p] = true
+		}
+	}
+}
+
 // iterateCommitTrees iterate all reachable trees from the given commit
 func iterateCommitTrees(
 	seen map[plumbing.Hash]bool,