From af1d64b218b7c19bb4d84d9b7fa4b519a63f4197 Mon Sep 17 00:00:00 2001
From: teor <teor@riseup.net>
Date: Tue, 9 Jun 2020 21:17:50 +1000
Subject: [PATCH] consensus: Add a transaction verification stub

Part of #428.
---
 zebra-consensus/src/verify.rs             |  2 ++
 zebra-consensus/src/verify/transaction.rs | 22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 zebra-consensus/src/verify/transaction.rs

diff --git a/zebra-consensus/src/verify.rs b/zebra-consensus/src/verify.rs
index 909c4fa6..1d4d6272 100644
--- a/zebra-consensus/src/verify.rs
+++ b/zebra-consensus/src/verify.rs
@@ -18,6 +18,8 @@ use tower::{buffer::Buffer, Service};
 
 use zebra_chain::block::Block;
 
+mod transaction;
+
 /// Block verification service.
 ///
 /// After verification, blocks and their associated transactions are added to
diff --git a/zebra-consensus/src/verify/transaction.rs b/zebra-consensus/src/verify/transaction.rs
new file mode 100644
index 00000000..85c14e75
--- /dev/null
+++ b/zebra-consensus/src/verify/transaction.rs
@@ -0,0 +1,22 @@
+//! Transaction verification for Zebra.
+//!
+//! Verification occurs in multiple stages:
+//!   - getting transactions from blocks or the mempool (disk- or network-bound)
+//!   - context-free verification of signatures, proofs, and scripts (CPU-bound)
+//!   - context-dependent verification of transactions against the chain state
+//!     (awaits an up-to-date chain)
+//!
+//! Verification is provided via a `tower::Service`, to support backpressure and batch
+//! verification.
+//!
+//! This is an internal module. Use `verify::BlockVerifier` for blocks and their
+//! transactions, or `mempool::MempoolTransactionVerifier` for mempool transactions.
+
+/// Internal transaction verification service.
+///
+/// After verification, the transaction future completes. State changes are handled by
+/// `BlockVerifier` or `MempoolTransactionVerifier`.
+///
+/// `TransactionVerifier` is not yet implemented.
+#[derive(Default)]
+pub(crate) struct TransactionVerifier {}