From 10eeced227fe1be279e2ef92dea1ee8a02d86f5c Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Wed, 17 Apr 2019 11:18:00 +1000
Subject: [PATCH] Remove SSZ dep from `tree_hash`

---
 eth2/utils/tree_hash/Cargo.toml               |  1 -
 .../tree_hash/src/cached_tree_hash/impls.rs   |  5 ++--
 eth2/utils/tree_hash/src/lib.rs               | 23 ----------------
 .../utils/tree_hash/src/standard_tree_hash.rs |  1 -
 .../tree_hash/src/standard_tree_hash/impls.rs | 27 +++++++++++++++----
 5 files changed, 24 insertions(+), 33 deletions(-)

diff --git a/eth2/utils/tree_hash/Cargo.toml b/eth2/utils/tree_hash/Cargo.toml
index 243a49446..328d91577 100644
--- a/eth2/utils/tree_hash/Cargo.toml
+++ b/eth2/utils/tree_hash/Cargo.toml
@@ -8,4 +8,3 @@ edition = "2018"
 ethereum-types = "0.5"
 hashing = { path = "../hashing" }
 int_to_bytes = { path = "../int_to_bytes" }
-ssz = { path = "../ssz" }
diff --git a/eth2/utils/tree_hash/src/cached_tree_hash/impls.rs b/eth2/utils/tree_hash/src/cached_tree_hash/impls.rs
index 62d013881..6500e4eff 100644
--- a/eth2/utils/tree_hash/src/cached_tree_hash/impls.rs
+++ b/eth2/utils/tree_hash/src/cached_tree_hash/impls.rs
@@ -1,13 +1,12 @@
 use super::resize::{grow_merkle_cache, shrink_merkle_cache};
 use super::*;
-use ssz::ssz_encode;
 
 mod vec;
 
 impl CachedTreeHashSubTree<u64> for u64 {
     fn new_tree_hash_cache(&self) -> Result<TreeHashCache, Error> {
         Ok(TreeHashCache::from_bytes(
-            merkleize(ssz_encode(self)),
+            merkleize(self.to_le_bytes().to_vec()),
             false,
         )?)
     }
@@ -23,7 +22,7 @@ impl CachedTreeHashSubTree<u64> for u64 {
         chunk: usize,
     ) -> Result<usize, Error> {
         if self != other {
-            let leaf = merkleize(ssz_encode(self));
+            let leaf = merkleize(self.to_le_bytes().to_vec());
             cache.modify_chunk(chunk, &leaf)?;
         }
 
diff --git a/eth2/utils/tree_hash/src/lib.rs b/eth2/utils/tree_hash/src/lib.rs
index fe2001002..fd1708a2d 100644
--- a/eth2/utils/tree_hash/src/lib.rs
+++ b/eth2/utils/tree_hash/src/lib.rs
@@ -49,26 +49,3 @@ macro_rules! impl_tree_hash_for_ssz_bytes {
         }
     };
 }
-
-#[macro_export]
-macro_rules! impl_vec_as_fixed_len {
-    ($type: ty) => {
-        impl tree_hash::TreeHash for $type {
-            fn tree_hash_type() -> tree_hash::TreeHashType {
-                tree_hash::TreeHashType::Vector
-            }
-
-            fn tree_hash_packed_encoding(&self) -> Vec<u8> {
-                unreachable!("Vector should never be packed.")
-            }
-
-            fn tree_hash_packing_factor() -> usize {
-                unreachable!("Vector should never be packed.")
-            }
-
-            fn tree_hash_root(&self) -> Vec<u8> {
-                tree_hash::standard_tree_hash::vec_tree_hash_root(self)
-            }
-        }
-    };
-}
diff --git a/eth2/utils/tree_hash/src/standard_tree_hash.rs b/eth2/utils/tree_hash/src/standard_tree_hash.rs
index 130c360ed..812a2c352 100644
--- a/eth2/utils/tree_hash/src/standard_tree_hash.rs
+++ b/eth2/utils/tree_hash/src/standard_tree_hash.rs
@@ -1,7 +1,6 @@
 use super::*;
 use hashing::hash;
 use int_to_bytes::int_to_bytes32;
-use ssz::ssz_encode;
 
 pub use impls::vec_tree_hash_root;
 
diff --git a/eth2/utils/tree_hash/src/standard_tree_hash/impls.rs b/eth2/utils/tree_hash/src/standard_tree_hash/impls.rs
index c3be8d55b..be6b4ba07 100644
--- a/eth2/utils/tree_hash/src/standard_tree_hash/impls.rs
+++ b/eth2/utils/tree_hash/src/standard_tree_hash/impls.rs
@@ -9,7 +9,7 @@ macro_rules! impl_for_bitsize {
             }
 
             fn tree_hash_packed_encoding(&self) -> Vec<u8> {
-                ssz_encode(self)
+                self.to_le_bytes().to_vec()
             }
 
             fn tree_hash_packing_factor() -> usize {
@@ -28,7 +28,24 @@ impl_for_bitsize!(u16, 16);
 impl_for_bitsize!(u32, 32);
 impl_for_bitsize!(u64, 64);
 impl_for_bitsize!(usize, 64);
-impl_for_bitsize!(bool, 8);
+
+impl TreeHash for bool {
+    fn tree_hash_type() -> TreeHashType {
+        TreeHashType::Basic
+    }
+
+    fn tree_hash_packed_encoding(&self) -> Vec<u8> {
+        (*self as u8).tree_hash_packed_encoding()
+    }
+
+    fn tree_hash_packing_factor() -> usize {
+        u8::tree_hash_packing_factor()
+    }
+
+    fn tree_hash_root(&self) -> Vec<u8> {
+        int_to_bytes32(*self as u64)
+    }
+}
 
 impl TreeHash for [u8; 4] {
     fn tree_hash_type() -> TreeHashType {
@@ -44,7 +61,7 @@ impl TreeHash for [u8; 4] {
     }
 
     fn tree_hash_root(&self) -> Vec<u8> {
-        merkle_root(&ssz::ssz_encode(self))
+        merkle_root(&self[..])
     }
 }
 
@@ -54,7 +71,7 @@ impl TreeHash for H256 {
     }
 
     fn tree_hash_packed_encoding(&self) -> Vec<u8> {
-        ssz_encode(self)
+        self.as_bytes().to_vec()
     }
 
     fn tree_hash_packing_factor() -> usize {
@@ -62,7 +79,7 @@ impl TreeHash for H256 {
     }
 
     fn tree_hash_root(&self) -> Vec<u8> {
-        merkle_root(&ssz::ssz_encode(self))
+        merkle_root(&self.as_bytes().to_vec())
     }
 }