1 files changed, 90 insertions, 0 deletions
diff --git a/libgo/go/html/template/clone.go b/libgo/go/html/template/clone.go
new file mode 100644
index 0000000..d0d8ea4
--- /dev/null
+++ b/libgo/go/html/template/clone.go
@@ -0,0 +1,90 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package template
+
+import (
+	"text/template/parse"
+)
+
+// clone clones a template Node.
+func clone(n parse.Node) parse.Node {
+	switch t := n.(type) {
+	case *parse.ActionNode:
+		return cloneAction(t)
+	case *parse.IfNode:
+		b := new(parse.IfNode)
+		copyBranch(&b.BranchNode, &t.BranchNode)
+		return b
+	case *parse.ListNode:
+		return cloneList(t)
+	case *parse.RangeNode:
+		b := new(parse.RangeNode)
+		copyBranch(&b.BranchNode, &t.BranchNode)
+		return b
+	case *parse.TemplateNode:
+		return cloneTemplate(t)
+	case *parse.TextNode:
+		return cloneText(t)
+	case *parse.WithNode:
+		b := new(parse.WithNode)
+		copyBranch(&b.BranchNode, &t.BranchNode)
+		return b
+	}
+	panic("cloning " + n.String() + " is unimplemented")
+}
+
+// cloneAction returns a deep clone of n.
+func cloneAction(n *parse.ActionNode) *parse.ActionNode {
+	// We use keyless fields because they won't compile if a field is added.
+	return &parse.ActionNode{n.NodeType, n.Line, clonePipe(n.Pipe)}
+}
+
+// cloneList returns a deep clone of n.
+func cloneList(n *parse.ListNode) *parse.ListNode {
+	if n == nil {
+		return nil
+	}
+	// We use keyless fields because they won't compile if a field is added.
+	c := parse.ListNode{n.NodeType, make([]parse.Node, len(n.Nodes))}
+	for i, child := range n.Nodes {
+		c.Nodes[i] = clone(child)
+	}
+	return &c
+}
+
+// clonePipe returns a shallow clone of n.
+// The escaper does not modify pipe descendants in place so there's no need to
+// clone deeply.
+func clonePipe(n *parse.PipeNode) *parse.PipeNode {
+	if n == nil {
+		return nil
+	}
+	// We use keyless fields because they won't compile if a field is added.
+	return &parse.PipeNode{n.NodeType, n.Line, n.Decl, n.Cmds}
+}
+
+// cloneTemplate returns a deep clone of n.
+func cloneTemplate(n *parse.TemplateNode) *parse.TemplateNode {
+	// We use keyless fields because they won't compile if a field is added.
+	return &parse.TemplateNode{n.NodeType, n.Line, n.Name, clonePipe(n.Pipe)}
+}
+
+// cloneText clones the given node sharing its []byte.
+func cloneText(n *parse.TextNode) *parse.TextNode {
+	// We use keyless fields because they won't compile if a field is added.
+	return &parse.TextNode{n.NodeType, n.Text}
+}
+
+// copyBranch clones src into dst.
+func copyBranch(dst, src *parse.BranchNode) {
+	// We use keyless fields because they won't compile if a field is added.
+	*dst = parse.BranchNode{
+		src.NodeType,
+		src.Line,
+		clonePipe(src.Pipe),
+		cloneList(src.List),
+		cloneList(src.ElseList),
+	}
+}