feat: get addresses from transparent outputs (#3802)

* feat: add Output::address()

* test transactions in test blocks

zebra-chain/src/primitives/zcash_primitives.rs

@@ -9,7 +9,7 @@ use std::{
 
 use crate::{
     amount::{Amount, NonNegative},
-    parameters::NetworkUpgrade,
+    parameters::{Network, NetworkUpgrade},
     serialization::ZcashSerialize,
     transaction::{AuthDigest, HashType, SigHash, Transaction},
     transparent::{self, Script},
@@ -148,3 +148,23 @@ pub(crate) fn auth_digest(trans: &Transaction) -> AuthDigest {
 
     AuthDigest(digest_bytes)
 }
+
+/// Return the destination address from a transparent output.
+///
+/// Returns None if the address type is not valid or unrecognized.
+pub(crate) fn transparent_output_address(
+    output: &transparent::Output,
+    network: Network,
+) -> Option<transparent::Address> {
+    let script = zcash_primitives::legacy::Script::from(&output.lock_script);
+    let alt_addr = script.address();
+    match alt_addr {
+        Some(zcash_primitives::legacy::TransparentAddress::PublicKey(pub_key_hash)) => Some(
+            transparent::Address::from_pub_key_hash(network, pub_key_hash),
+        ),
+        Some(zcash_primitives::legacy::TransparentAddress::Script(script_hash)) => {
+            Some(transparent::Address::from_script_hash(network, script_hash))
+        }
+        None => None,
+    }
+}

zebra-chain/src/transparent.rs

@@ -30,7 +30,10 @@ mod tests;
 
 use crate::{
     amount::{Amount, NonNegative},
-    block, transaction,
+    block,
+    parameters::Network,
+    primitives::zcash_primitives,
+    transaction,
 };
 
 use std::{collections::HashMap, fmt, iter};
@@ -303,4 +306,11 @@ impl Output {
     pub fn value(&self) -> Amount<NonNegative> {
         self.value
     }
+
+    /// Return the destination address from a transparent output.
+    ///
+    /// Returns None if the address type is not valid or unrecognized.
+    pub fn address(&self, network: Network) -> Option<Address> {
+        zcash_primitives::transparent_output_address(self, network)
+    }
 }

zebra-chain/src/transparent/address.rs

@@ -192,6 +192,22 @@ impl ToAddressWithNetwork for PublicKey {
 }
 
 impl Address {
+    /// Create an address for the given public key hash and network.
+    pub fn from_pub_key_hash(network: Network, pub_key_hash: [u8; 20]) -> Self {
+        Self::PayToPublicKeyHash {
+            network,
+            pub_key_hash,
+        }
+    }
+
+    /// Create an address for the given script hash and network.
+    pub fn from_script_hash(network: Network, script_hash: [u8; 20]) -> Self {
+        Self::PayToScriptHash {
+            network,
+            script_hash,
+        }
+    }
+
     /// A hash of a transparent address payload, as used in
     /// transparent pay-to-script-hash and pay-to-publickey-hash
     /// addresses.

zebra-chain/src/transparent/tests/vectors.rs

@@ -1,4 +1,13 @@
+use std::sync::Arc;
+
 use super::super::serialize::parse_coinbase_height;
+use crate::{
+    block::Block, parameters::Network, primitives::zcash_primitives::transparent_output_address,
+    serialization::ZcashDeserializeInto, transaction,
+};
+use hex::FromHex;
+
+use zebra_test::prelude::*;
 
 #[test]
 fn parse_coinbase_height_mins() {
@@ -37,3 +46,83 @@ fn parse_coinbase_height_mins() {
     let case4 = vec![0x04, 0x11, 0x00, 0x00, 0x00];
     assert!(parse_coinbase_height(case4).is_err());
 }
+
+#[test]
+fn get_transparent_output_address() -> Result<()> {
+    zebra_test::init();
+
+    let script_tx: Vec<u8> = <Vec<u8>>::from_hex("0400008085202f8901fcaf44919d4a17f6181a02a7ebe0420be6f7dad1ef86755b81d5a9567456653c010000006a473044022035224ed7276e61affd53315eca059c92876bc2df61d84277cafd7af61d4dbf4002203ed72ea497a9f6b38eb29df08e830d99e32377edb8a574b8a289024f0241d7c40121031f54b095eae066d96b2557c1f99e40e967978a5fd117465dbec0986ca74201a6feffffff020050d6dc0100000017a9141b8a9bda4b62cd0d0582b55455d0778c86f8628f870d03c812030000001976a914e4ff5512ffafe9287992a1cd177ca6e408e0300388ac62070d0095070d000000000000000000000000")
+    .expect("Block bytes are in valid hex representation");
+
+    let transaction = script_tx.zcash_deserialize_into::<Arc<transaction::Transaction>>()?;
+
+    // Hashes were extracted from the transaction (parsed with zebra-chain,
+    // then manually extracted from lock_script).
+    // Final expected values were generated with https://secretscan.org/PrivateKeyHex,
+    // by filling field 4 with the prefix followed by the address hash.
+    // Refer to <https://zips.z.cash/protocol/protocol.pdf#transparentaddrencoding>
+    // for the prefixes.
+
+    // Script hash 1b8a9bda4b62cd0d0582b55455d0778c86f8628f
+    let addr = transparent_output_address(&transaction.outputs()[0], Network::Mainnet)
+        .expect("should return address");
+    assert_eq!(addr.to_string(), "t3M5FDmPfWNRG3HRLddbicsuSCvKuk9hxzZ");
+    let addr = transparent_output_address(&transaction.outputs()[0], Network::Testnet)
+        .expect("should return address");
+    assert_eq!(addr.to_string(), "t294SGSVoNq2daz15ZNbmAW65KQZ5e3nN5G");
+    // Public key hash e4ff5512ffafe9287992a1cd177ca6e408e03003
+    let addr = transparent_output_address(&transaction.outputs()[1], Network::Mainnet)
+        .expect("should return address");
+    assert_eq!(addr.to_string(), "t1ekRwsd4LaSsd6NXgsx66q2HxQWTLCF44y");
+    let addr = transparent_output_address(&transaction.outputs()[1], Network::Testnet)
+        .expect("should return address");
+    assert_eq!(addr.to_string(), "tmWbBGi7TjExNmLZyMcFpxVh3ZPbGrpbX3H");
+
+    Ok(())
+}
+
+#[test]
+fn get_transparent_output_address_with_blocks() {
+    zebra_test::init();
+
+    get_transparent_output_address_with_blocks_for_network(Network::Mainnet);
+    get_transparent_output_address_with_blocks_for_network(Network::Testnet);
+}
+
+/// Test that the block test vector indexes match the heights in the block data,
+/// and that each post-sapling block has a corresponding final sapling root.
+fn get_transparent_output_address_with_blocks_for_network(network: Network) {
+    let block_iter = match network {
+        Network::Mainnet => zebra_test::vectors::MAINNET_BLOCKS.iter(),
+        Network::Testnet => zebra_test::vectors::TESTNET_BLOCKS.iter(),
+    };
+
+    let mut valid_addresses = 0;
+
+    for (&height, block_bytes) in block_iter.skip(1) {
+        let block = block_bytes
+            .zcash_deserialize_into::<Block>()
+            .expect("block is structurally valid");
+
+        for (idx, tx) in block.transactions.iter().enumerate() {
+            for output in tx.outputs() {
+                let addr = output.address(network);
+                if addr.is_none() && idx == 0 && output.lock_script.as_raw_bytes()[0] == 0x21 {
+                    // There are a bunch of coinbase transactions with pay-to-pubkey scripts
+                    // which we don't support; skip them
+                    continue;
+                }
+                assert!(
+                    addr.is_some(),
+                    "address of {:?}; block #{}; tx #{}; must not be None",
+                    output,
+                    height,
+                    idx,
+                );
+                valid_addresses += 1;
+            }
+        }
+    }
+    // Make sure we didn't accidentally skip all vectors
+    assert!(valid_addresses > 0);
+}