From 0cbfeaab94945a37018f0fb1cc69ac161aa60c5d Mon Sep 17 00:00:00 2001
From: Antioch Peverell <apeverell@protonmail.com>
Date: Mon, 3 Sep 2018 12:35:37 +0100
Subject: [PATCH] Faster tx known check (#1468)

* fast check for known tx when adding to pool

* rustfmt
---
 pool/src/pool.rs             | 5 +++++
 pool/src/transaction_pool.rs | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/pool/src/pool.rs b/pool/src/pool.rs
index b4bcb9b6f..03565853e 100644
--- a/pool/src/pool.rs
+++ b/pool/src/pool.rs
@@ -57,6 +57,11 @@ impl Pool {
 		}
 	}
 
+	/// Does the transaction pool contain an entry for the given transaction?
+	pub fn contains_tx(&self, tx: &Transaction) -> bool {
+		self.entries.iter().any(|x| x.tx.hash() == tx.hash())
+	}
+
 	/// Query the tx pool for all known txs based on kernel short_ids
 	/// from the provided compact_block.
 	/// Note: does not validate that we return the full set of required txs.
diff --git a/pool/src/transaction_pool.rs b/pool/src/transaction_pool.rs
index 4ff236200..ce9b3ab5f 100644
--- a/pool/src/transaction_pool.rs
+++ b/pool/src/transaction_pool.rs
@@ -101,6 +101,12 @@ impl TransactionPool {
 		stem: bool,
 		block_hash: &Hash,
 	) -> Result<(), PoolError> {
+		// Quick check to deal with common case of seeing the *same* tx
+		// broadcast from multiple peers simultaneously.
+		if !stem && self.txpool.contains_tx(&tx) {
+			return Err(PoolError::DuplicateTx);
+		}
+
 		// Do we have the capacity to accept this transaction?
 		self.is_acceptable(&tx)?;