Transaction broadcast (#209)

* Add transaction broadcast to all known peers once they have been
accepted by our own transaction pool.
* Some debug log

Fixes #200

pool/src/lib.rs

@@ -37,4 +37,4 @@ extern crate grin_keychain as keychain;
 extern crate secp256k1zkp as secp;
 
 pub use pool::TransactionPool;
-pub use types::{BlockChain, TxSource, PoolError, PoolConfig};
+pub use types::{BlockChain, PoolAdapter, TxSource, PoolError, PoolConfig};

pool/src/pool.rs

@@ -43,6 +43,7 @@ pub struct TransactionPool<T> {
 	// blockchain is a DummyChain, for now, which mimics what the future
 	// chain will offer to the pool
 	blockchain: Arc<T>,
+	adapter: Arc<PoolAdapter>,
 }
 
 impl<T> TransactionPool<T>
@@ -50,13 +51,14 @@ where
 	T: BlockChain,
 {
 	/// Create a new transaction pool
-	pub fn new(config: PoolConfig, chain: Arc<T>) -> TransactionPool<T> {
+	pub fn new(config: PoolConfig, chain: Arc<T>, adapter: Arc<PoolAdapter>) -> TransactionPool<T> {
 		TransactionPool {
 			config: config,
 			transactions: HashMap::new(),
 			pool: Pool::empty(),
 			orphans: Orphans::empty(),
 			blockchain: chain,
+			adapter: adapter,
 		}
 	}
 
@@ -241,6 +243,7 @@ where
 			);
 
 			self.reconcile_orphans().unwrap();
+			self.adapter.tx_accepted(&tx);
 			self.transactions.insert(tx_hash, Box::new(tx));
 			Ok(())
 
@@ -1196,6 +1199,7 @@ mod tests {
 			pool: Pool::empty(),
 			orphans: Orphans::empty(),
 			blockchain: dummy_chain.clone(),
+			adapter: Arc::new(NoopAdapter{}),
 		}
 	}
 

pool/src/types.rs

@@ -163,6 +163,21 @@ pub trait BlockChain {
 	fn head_header(&self) -> Result<block::BlockHeader, PoolError>;
 }
 
+/// Bridge between the transaction pool and the rest of the system. Handles
+/// downstream processing of valid transactions by the rest of the system, most
+/// importantly the broadcasting of transactions to our peers.
+pub trait PoolAdapter: Send + Sync {
+	/// The transaction pool has accepted this transactions as valid and added
+	/// it to its internal cache.
+	fn tx_accepted(&self, tx: &transaction::Transaction);
+}
+
+/// Dummy adapter used as a placeholder for real implementations
+pub struct NoopAdapter {}
+impl PoolAdapter for NoopAdapter {
+	fn tx_accepted(&self, _: &transaction::Transaction) {}
+}
+
 /// Pool contains the elements of the graph that are connected, in full, to
 /// the blockchain.
 /// Reservations of outputs by orphan transactions (not fully connected) are