Refactor rewind single header (#1390)

* refactor txhashset to only take a single header
no need to pass in current head_header each time

* rustfmt

* fix bug introduced in rewind with LMDB

* rustfmt

* add some comments

chain/tests/data_file_integrity.rs

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+extern crate chrono;
 extern crate env_logger;
 extern crate grin_chain as chain;
 extern crate grin_core as core;
@@ -20,14 +21,13 @@ extern crate grin_store as store;
 extern crate grin_util as util;
 extern crate grin_wallet as wallet;
 extern crate rand;
-extern crate chrono;
 
+use chrono::Duration;
 use std::fs;
 use std::sync::Arc;
-use chrono::Duration;
 
-use chain::Chain;
 use chain::types::{NoopAdapter, Tip};
+use chain::Chain;
 use core::core::target::Difficulty;
 use core::core::{Block, BlockHeader, Transaction};
 use core::global::{self, ChainTypes};
@@ -96,8 +96,6 @@ fn data_files() {
 				.process_block(b.clone(), chain::Options::MINE)
 				.unwrap();
 
-			let head = Tip::from_block(&b.header);
-
 			chain.validate(false).unwrap();
 		}
 	}

chain/tests/mine_simple_chain.rs

@@ -242,7 +242,6 @@ fn spend_in_fork_and_compact() {
 	// mine the first block and keep track of the block_hash
 	// so we can spend the coinbase later
 	let b = prepare_block(&kc, &fork_head, &chain, 2);
-	let block_hash = b.hash();
 	let out_id = OutputIdentifier::from_output(&b.outputs()[0]);
 	assert!(out_id.features.contains(OutputFeatures::COINBASE_OUTPUT));
 	fork_head = b.header.clone();
@@ -250,8 +249,6 @@ fn spend_in_fork_and_compact() {
 		.process_block(b.clone(), chain::Options::SKIP_POW)
 		.unwrap();
 
-	let merkle_proof = chain.get_merkle_proof(&out_id, &b.header).unwrap();
-
 	// now mine three further blocks
 	for n in 3..6 {
 		let b = prepare_block(&kc, &fork_head, &chain, n);

chain/tests/store_indices.rs

@@ -23,7 +23,7 @@ extern crate rand;
 use std::fs;
 use std::sync::Arc;
 
-use chain::{ChainStore, Tip};
+use chain::Tip;
 use core::core::hash::Hashed;
 use core::core::target::Difficulty;
 use core::core::{Block, BlockHeader};

chain/tests/test_coinbase_maturity.rs

@@ -26,7 +26,7 @@ use std::fs;
 use std::sync::Arc;
 
 use chain::types::NoopAdapter;
-use chain::{Error, ErrorKind};
+use chain::ErrorKind;
 use core::core::target::Difficulty;
 use core::core::{transaction, OutputIdentifier};
 use core::global::{self, ChainTypes};
@@ -86,17 +86,10 @@ fn test_coinbase_maturity() {
 			.contains(transaction::OutputFeatures::COINBASE_OUTPUT)
 	);
 
-	let out_id = OutputIdentifier::from_output(&coinbase_output);
-
-	// we will need this later when we want to spend the coinbase output
-	let block_hash = block.hash();
-
 	chain
 		.process_block(block.clone(), chain::Options::MINE)
 		.unwrap();
 
-	let merkle_proof = chain.get_merkle_proof(&out_id, &block.header).unwrap();
-
 	let prev = chain.head_header().unwrap();
 
 	let amount = consensus::REWARD;