Simplify mining header serialization (#1509)

core/src/ser.rs

@@ -403,10 +403,16 @@ impl Writeable for Signature {
 
 /// Utility wrapper for an underlying byte Writer. Defines higher level methods
 /// to write numbers, byte vectors, hashes, etc.
-struct BinWriter<'a> {
+pub struct BinWriter<'a> {
 	sink: &'a mut Write,
 }
 
+impl<'a> BinWriter<'a> {
+	pub fn new(write: &'a mut Write) -> BinWriter<'a> {
+		BinWriter{sink: write}
+	}
+}
+
 impl<'a> Writer for BinWriter<'a> {
 	fn serialization_mode(&self) -> SerializationMode {
 		SerializationMode::Full

servers/src/mining/mine_block.rs

@@ -16,7 +16,6 @@
 //! them into a block and returns it.
 
 use chrono::prelude::{DateTime, NaiveDateTime, Utc};
-use itertools::Itertools;
 use rand::{self, Rng};
 use std::sync::{Arc, RwLock};
 use std::thread;
@@ -25,52 +24,12 @@ use std::time::Duration;
 use chain;
 use common::types::Error;
 use core::core::verifier_cache::VerifierCache;
-use core::ser::{self, AsFixedBytes};
-use core::{consensus, core};
+use core::{consensus, core, ser};
 use keychain::{ExtKeychain, Identifier, Keychain};
 use pool;
 use util::{self, LOGGER};
 use wallet::{self, BlockFees};
 
-/// Serializer that outputs the pre-pow part of the header,
-/// including the nonce (last 8 bytes) that can be sent off
-/// to the miner to mutate at will
-pub struct HeaderPrePowWriter {
-	pub pre_pow: Vec<u8>,
-}
-
-impl Default for HeaderPrePowWriter {
-	fn default() -> HeaderPrePowWriter {
-		HeaderPrePowWriter {
-			pre_pow: Vec::new(),
-		}
-	}
-}
-
-impl HeaderPrePowWriter {
-	pub fn as_hex_string(&self, include_nonce: bool) -> String {
-		let mut result = String::from(format!("{:02x}", self.pre_pow.iter().format("")));
-		if !include_nonce {
-			let l = result.len() - 16;
-			result.truncate(l);
-		}
-		result
-	}
-}
-
-impl ser::Writer for HeaderPrePowWriter {
-	fn serialization_mode(&self) -> ser::SerializationMode {
-		ser::SerializationMode::Full
-	}
-
-	fn write_fixed_bytes<T: AsFixedBytes>(&mut self, bytes_in: &T) -> Result<(), ser::Error> {
-		for i in 0..bytes_in.len() {
-			self.pre_pow.push(bytes_in.as_ref()[i])
-		}
-		Ok(())
-	}
-}
-
 // Ensure a block suitable for mining is built and returned
 // If a wallet listener URL is not provided the reward will be "burnt"
 // Warning: This call does not return until/unless a new block can be built

servers/src/mining/stratumserver.rs

@@ -30,11 +30,11 @@ use common::stats::{StratumStats, WorkerStats};
 use common::types::{StratumServerConfig, SyncState};
 use core::core::verifier_cache::VerifierCache;
 use core::core::Block;
-use core::{global, pow};
+use core::{global, pow, ser};
 use keychain;
 use mining::mine_block;
 use pool;
-use util::LOGGER;
+use util::{LOGGER, self};
 
 // ----------------------------------------
 // http://www.jsonrpc.org/specification
@@ -266,15 +266,17 @@ impl StratumServer {
 	fn build_block_template(&self) -> JobTemplate {
 		let bh = self.current_block_versions.last().unwrap().header.clone();
 		// Serialize the block header into pre and post nonce strings
-		let mut pre_pow_writer = mine_block::HeaderPrePowWriter::default();
-		bh.write_pre_pow(&mut pre_pow_writer).unwrap();
-		bh.pow.write_pre_pow(bh.version, &mut pre_pow_writer).unwrap();
-		let pre = pre_pow_writer.as_hex_string(false);
+		let mut header_buf = vec![];
+		{
+			let mut writer = ser::BinWriter::new(&mut header_buf);
+			bh.write_pre_pow(&mut writer).unwrap();
+		}
+		let pre_pow = util::to_hex(header_buf);
 		let job_template = JobTemplate {
 			height: bh.height,
 			job_id: (self.current_block_versions.len() - 1) as u64,
 			difficulty: self.minimum_share_difficulty,
-			pre_pow: pre,
+			pre_pow,
 		};
 		return job_template;
 	}