chain: move merkle_tree to block::merkle.

This Merkle tree is the SHA256d one used only for including transactions
in a block, so it should be kept there in order to not be confused with
other Merkle trees (like the note commitment trees).

zebra-chain/src/block.rs

@@ -10,6 +10,8 @@ mod height;
 mod root_hash;
 mod serialize;
 
+pub mod merkle;
+
 #[cfg(test)]
 mod tests;
 

zebra-chain/src/block/header.rs

@@ -1,10 +1,9 @@
 use chrono::{DateTime, Duration, Utc};
 
-use crate::merkle_tree::MerkleTreeRootHash;
 use crate::serialization::ZcashSerialize;
 use crate::work::{difficulty::CompactDifficulty, equihash::Solution};
 
-use super::{BlockHeaderHash, Error};
+use super::{merkle::MerkleTreeRootHash, BlockHeaderHash, Error};
 
 /// Block header.
 ///

zebra-chain/src/block/serialize.rs

@@ -2,11 +2,11 @@ use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use chrono::{TimeZone, Utc};
 use std::io;
 
-use crate::merkle_tree::MerkleTreeRootHash;
 use crate::serialization::ZcashDeserializeInto;
 use crate::serialization::{ReadZcashExt, SerializationError, ZcashDeserialize, ZcashSerialize};
 use crate::work::{difficulty::CompactDifficulty, equihash};
 
+use super::merkle::MerkleTreeRootHash;
 use super::Block;
 use super::BlockHeader;
 use super::BlockHeaderHash;

zebra-chain/src/block/tests/arbitrary.rs

@@ -1,4 +1,3 @@
-use crate::merkle_tree::MerkleTreeRootHash;
 use crate::parameters::Network;
 use crate::work::{difficulty::CompactDifficulty, equihash};
 
@@ -32,7 +31,7 @@ impl Arbitrary for BlockHeader {
             // version is interpreted as i32 in the spec, so we are limited to i32::MAX here
             (4u32..(i32::MAX as u32)),
             any::<BlockHeaderHash>(),
-            any::<MerkleTreeRootHash>(),
+            any::<merkle::MerkleTreeRootHash>(),
             any::<[u8; 32]>(),
             // time is interpreted as u32 in the spec, but rust timestamps are i64
             (0i64..(u32::MAX as i64)),

zebra-chain/src/lib.rs

@@ -11,8 +11,6 @@
 #[macro_use]
 extern crate serde;
 
-mod merkle_tree;
-
 pub mod amount;
 pub mod block;
 pub mod parameters;