introduce cpu_pool to read_msg (#477)

* introduce cpu_pool to read_msg

* cleanup and less unwrap() in handler

* expose cpu_pool as part of net_adapter (reuse across all peer connections and handlers)

* fix DummyAdaptor for test usage

* add new() to DummyAdapter for convenience

grin/src/adapters.rs

@@ -16,6 +16,8 @@ use std::net::SocketAddr;
 use std::sync::{Arc, RwLock};
 use std::sync::atomic::{AtomicBool, Ordering};
 
+use cpupool::CpuPool;
+
 use chain::{self, ChainAdapter};
 use core::core::{self, Output};
 use core::core::block::BlockHeader;
@@ -36,9 +38,14 @@ pub struct NetToChainAdapter {
 	p2p_server: OneTime<Arc<p2p::Server>>,
 	tx_pool: Arc<RwLock<pool::TransactionPool<PoolToChainAdapter>>>,
 	syncing: AtomicBool,
+	cpu_pool: CpuPool,
 }
 
 impl NetAdapter for NetToChainAdapter {
+	fn cpu_pool(&self) -> CpuPool {
+		self.cpu_pool.clone()
+	}
+
 	fn total_difficulty(&self) -> Difficulty {
 		self.chain.total_difficulty()
 	}
@@ -275,6 +282,7 @@ impl NetToChainAdapter {
 			p2p_server: OneTime::new(),
 			tx_pool: tx_pool,
 			syncing: AtomicBool::new(true),
+			cpu_pool: CpuPool::new(1),
 		}
 	}