From fdf704f6ae65e3a42e3d8def96ae56357b96900d Mon Sep 17 00:00:00 2001
From: Svyatoslav Nikolsky <svyatonik@gmail.com>
Date: Mon, 12 Dec 2016 00:56:32 +0300
Subject: [PATCH] check mempool::is_spent in
 ChainMemoryPoolTransactionOutputProvider::is_spent

---
 sync/src/synchronization_chain.rs    |  6 +++++
 sync/src/synchronization_verifier.rs | 35 ++++++++++++++++++++++------
 2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/sync/src/synchronization_chain.rs b/sync/src/synchronization_chain.rs
index b40e51ae..1a1299f6 100644
--- a/sync/src/synchronization_chain.rs
+++ b/sync/src/synchronization_chain.rs
@@ -195,6 +195,12 @@ impl Chain {
 		&self.memory_pool
 	}
 
+	/// Get mutable memory pool
+	#[cfg(test)]
+	pub fn memory_pool_mut(&mut self) -> &mut MemoryPool {
+		&mut self.memory_pool
+	}
+
 	/// Get number of blocks in given state
 	pub fn length_of_blocks_state(&self, state: BlockState) -> u32 {
 		match state {
diff --git a/sync/src/synchronization_verifier.rs b/sync/src/synchronization_verifier.rs
index aee732f5..dd4e8ecb 100644
--- a/sync/src/synchronization_verifier.rs
+++ b/sync/src/synchronization_verifier.rs
@@ -198,16 +198,19 @@ impl ChainMemoryPoolTransactionOutputProvider {
 
 impl PreviousTransactionOutputProvider for ChainMemoryPoolTransactionOutputProvider {
 	fn previous_transaction_output(&self, prevout: &OutPoint) -> Option<TransactionOutput> {
-		self.chain.read().memory_pool().previous_transaction_output(prevout)
+		let chain = self.chain.read();
+		chain.memory_pool().previous_transaction_output(prevout)
+			.or_else(|| chain.storage().as_previous_transaction_output_provider().previous_transaction_output(prevout))
 	}
 }
 
 impl TransactionOutputObserver for ChainMemoryPoolTransactionOutputProvider {
 	fn is_spent(&self, prevout: &OutPoint) -> Option<bool> {
-		self.chain.read()
-			.storage()
-			.transaction_meta(&prevout.hash)
-			.and_then(|tm| tm.is_spent(prevout.index as usize))
+		let chain = self.chain.read();
+		if chain.memory_pool().is_spent(prevout) {
+			return Some(true);
+		}
+		chain.storage().transaction_meta(&prevout.hash).and_then(|tm| tm.is_spent(prevout.index as usize))
 	}
 }
 
@@ -227,12 +230,15 @@ impl TransactionOutputObserver for EmptyTransactionOutputProvider {
 pub mod tests {
 	use std::sync::Arc;
 	use std::collections::HashMap;
+	use parking_lot::RwLock;
 	use chain::Transaction;
+	use synchronization_chain::{Chain, ChainRef};
 	use synchronization_client::CoreVerificationSink;
 	use synchronization_executor::tests::DummyTaskExecutor;
 	use primitives::hash::H256;
-	use super::{Verifier, BlockVerificationSink, TransactionVerificationSink};
-	use db::IndexedBlock;
+	use super::{Verifier, BlockVerificationSink, TransactionVerificationSink, ChainMemoryPoolTransactionOutputProvider};
+	use db::{self, IndexedBlock};
+	use test_data;
 
 	#[derive(Default)]
 	pub struct DummyVerifier {
@@ -274,4 +280,19 @@ pub mod tests {
 			}
 		}
 	}
+
+	#[test]
+	fn when_transaction_spends_output_twice() {
+		use db::TransactionOutputObserver;
+		let tx1: Transaction = test_data::TransactionBuilder::with_default_input(0).into();
+		let tx2: Transaction = test_data::TransactionBuilder::with_default_input(1).into();
+		let out1 = tx1.inputs[0].previous_output.clone();
+		let out2 = tx2.inputs[0].previous_output.clone();
+		let mut chain = Chain::new(Arc::new(db::TestStorage::with_genesis_block()));
+		chain.memory_pool_mut().insert_verified(tx1);
+		let chain = ChainRef::new(RwLock::new(chain));
+		let provider = ChainMemoryPoolTransactionOutputProvider::with_chain(chain);
+		assert!(provider.is_spent(&out1).unwrap_or_default());
+		assert!(!provider.is_spent(&out2).unwrap_or_default());
+	}
 }