2 files changed, 50 insertions, 0 deletions
diff --git a/vendor/github.com/tchap/go-patricia/patricia/children.go b/vendor/github.com/tchap/go-patricia/patricia/children.go
index a5677c335..bcfd0a5dd 100644
--- a/vendor/github.com/tchap/go-patricia/patricia/children.go
+++ b/vendor/github.com/tchap/go-patricia/patricia/children.go
@@ -20,6 +20,7 @@ type childList interface {
 	next(b byte) *Trie
 	walk(prefix *Prefix, visitor VisitorFunc) error
 	print(w io.Writer, indent int)
+	clone() childList
 	total() int
 }
 
@@ -143,6 +144,17 @@ func (list *sparseChildList) total() int {
 	return tot
 }
 
+func (list *sparseChildList) clone() childList {
+	clones := make(tries, len(list.children), cap(list.children))
+	for i, child := range list.children {
+		clones[i] = child.Clone()
+	}
+
+	return &sparseChildList{
+		children: clones,
+	}
+}
+
 func (list *sparseChildList) print(w io.Writer, indent int) {
 	for _, child := range list.children {
 		if child != nil {
@@ -314,6 +326,32 @@ func (list *denseChildList) print(w io.Writer, indent int) {
 	}
 }
 
+func (list *denseChildList) clone() childList {
+	clones := make(tries, cap(list.children))
+
+	if list.numChildren != 0 {
+		clonedCount := 0
+		for i := list.headIndex; i < len(list.children); i++ {
+			child := list.children[i]
+			if child != nil {
+				clones[i] = child.Clone()
+				clonedCount++
+				if clonedCount == list.numChildren {
+					break
+				}
+			}
+		}
+	}
+
+	return &denseChildList{
+		min:         list.min,
+		max:         list.max,
+		numChildren: list.numChildren,
+		headIndex:   list.headIndex,
+		children:    clones,
+	}
+}
+
 func (list *denseChildList) total() int {
 	tot := 0
 	for _, child := range list.children {
diff --git a/vendor/github.com/tchap/go-patricia/patricia/patricia.go b/vendor/github.com/tchap/go-patricia/patricia/patricia.go
index a1fc53d5d..7b9975e38 100644
--- a/vendor/github.com/tchap/go-patricia/patricia/patricia.go
+++ b/vendor/github.com/tchap/go-patricia/patricia/patricia.go
@@ -77,6 +77,18 @@ func MaxChildrenPerSparseNode(value int) Option {
 	}
 }
 
+// Clone makes a copy of an existing trie.
+// Items stored in both tries become shared, obviously.
+func (trie *Trie) Clone() *Trie {
+	return &Trie{
+		prefix:                   append(Prefix(nil), trie.prefix...),
+		item:                     trie.item,
+		maxPrefixPerNode:         trie.maxPrefixPerNode,
+		maxChildrenPerSparseNode: trie.maxChildrenPerSparseNode,
+		children:                 trie.children.clone(),
+	}
+}
+
 // Item returns the item stored in the root of this trie.
 func (trie *Trie) Item() Item {
 	return trie.item