From 646b506e7adb66e26544713d69ee9dffba35e07f Mon Sep 17 00:00:00 2001
From: Deirdre Connolly <deirdre@zfnd.org>
Date: Wed, 12 Aug 2020 02:51:11 -0400
Subject: [PATCH] Whoops forgot to add sprout::NoteTreeRootHash

---
 zebra-chain/src/treestate/sprout.rs | 47 +++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 zebra-chain/src/treestate/sprout.rs

diff --git a/zebra-chain/src/treestate/sprout.rs b/zebra-chain/src/treestate/sprout.rs
new file mode 100644
index 00000000..11337742
--- /dev/null
+++ b/zebra-chain/src/treestate/sprout.rs
@@ -0,0 +1,47 @@
+//! Note Commitment Trees.
+//!
+//! A note commitment tree is an incremental Merkle tree of fixed depth
+//! used to store note commitments that JoinSplit transfers or Spend
+//! transfers produce. Just as the unspent transaction output set (UTXO
+//! set) used in Bitcoin, it is used to express the existence of value and
+//! the capability to spend it. However, unlike the UTXO set, it is not
+//! the job of this tree to protect against double-spending, as it is
+//! append-only.
+//!
+//! A root of a note commitment tree is associated with each treestate.
+#![allow(clippy::unit_arg)]
+
+use std::fmt;
+
+#[cfg(test)]
+use proptest_derive::Arbitrary;
+
+/// Sprout note commitment tree root node hash.
+///
+/// The root hash in LEBS2OSP256(rt) encoding of the Sprout note
+/// commitment tree corresponding to the final Sprout treestate of
+/// this block. A root of a note commitment tree is associated with
+/// each treestate.
+#[derive(Clone, Copy, Default, Eq, PartialEq, Serialize, Deserialize)]
+#[cfg_attr(test, derive(Arbitrary))]
+pub struct NoteTreeRootHash([u8; 32]);
+
+impl fmt::Debug for NoteTreeRootHash {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_tuple("SproutNoteTreeRootHash")
+            .field(&hex::encode(&self.0))
+            .finish()
+    }
+}
+
+impl From<[u8; 32]> for NoteTreeRootHash {
+    fn from(bytes: [u8; 32]) -> NoteTreeRootHash {
+        Self(bytes)
+    }
+}
+
+impl From<NoteTreeRootHash> for [u8; 32] {
+    fn from(rt: NoteTreeRootHash) -> [u8; 32] {
+        rt.0
+    }
+}