Add PSBT output data key-value map type

- Implement psbt::Map trait for psbt::Output
- Add (en)decoding logic for psbt::Output

- Implement PSBT (de)serialization trait for relevant psbt::Output types

- Add macro for merging fields for PSBT key-value maps
- Add macro for implementing decoding logic for PSBT key-value maps
- Add convenience macro for implementing both encoding and decoding
  logic for PSBT key-value maps
- Add macro for inserting raw PSBT key-value pairs into PSBT key-value
  maps
- Add macro for getting raw PSBT key-value pairs from PSBT key-value
  maps

src/consensus/encode.rs

@@ -518,6 +518,7 @@ impl_array!(8);
 impl_array!(12);
 impl_array!(16);
 impl_array!(32);
+impl_array!(33);
 
 impl<S: Encoder, T: Encodable<S>> Encodable<S> for [T] {
     #[inline]

src/util/psbt/macros.rs

@@ -1,3 +1,11 @@
+macro_rules! merge {
+    ($thing:ident, $slf:ident, $other:ident) => {
+        if let (&None, Some($thing)) = (&$slf.$thing, $other.$thing) {
+            $slf.$thing = Some($thing);
+        }
+    };
+}
+
 macro_rules! impl_psbt_de_serialize {
     ($thing:ty) => {
         impl_psbt_serialize!($thing);
@@ -38,3 +46,86 @@ macro_rules! impl_psbtmap_consensus_encoding {
         }
     };
 }
+
+macro_rules! impl_psbtmap_consensus_decoding {
+    ($thing:ty) => {
+        impl<D: ::consensus::encode::Decoder> ::consensus::encode::Decodable<D> for $thing {
+            fn consensus_decode(d: &mut D) -> Result<Self, ::consensus::encode::Error> {
+                let mut rv: Self = ::std::default::Default::default();
+
+                loop {
+                    match ::consensus::encode::Decodable::consensus_decode(d) {
+                        Ok(pair) => ::util::psbt::Map::insert_pair(&mut rv, pair)?,
+                        Err(::consensus::encode::Error::Psbt(::util::psbt::Error::NoMorePairs)) => return Ok(rv),
+                        Err(e) => return Err(e),
+                    }
+                }
+            }
+        }
+    };
+}
+
+macro_rules! impl_psbtmap_consensus_enc_dec_oding {
+    ($thing:ty) => {
+        impl_psbtmap_consensus_decoding!($thing);
+        impl_psbtmap_consensus_encoding!($thing);
+    };
+}
+
+#[cfg_attr(rustfmt, rustfmt_skip)]
+macro_rules! impl_psbt_insert_pair {
+    ($slf:ident.$unkeyed_name:ident <= <$raw_key:ident: _>|<$raw_value:ident: $unkeyed_value_type:ty>) => {
+        if $raw_key.key.is_empty() {
+            if let None = $slf.$unkeyed_name {
+                let val: $unkeyed_value_type = ::util::psbt::serialize::Deserialize::deserialize(&$raw_value)?;
+
+                $slf.$unkeyed_name = Some(val)
+            } else {
+                return Err(::util::psbt::Error::DuplicateKey($raw_key).into());
+            }
+        } else {
+            return Err(::util::psbt::Error::InvalidKey($raw_key).into());
+        }
+    };
+    ($slf:ident.$keyed_name:ident <= <$raw_key:ident: $keyed_key_type:ty>|<$raw_value:ident: $keyed_value_type:ty>) => {
+        if !$raw_key.key.is_empty() {
+            let key_val: $keyed_key_type = ::util::psbt::serialize::Deserialize::deserialize(&$raw_key.key)?;
+
+            if $slf.$keyed_name.contains_key(&key_val) {
+                return Err(::util::psbt::Error::DuplicateKey($raw_key).into());
+            } else {
+                let val: $keyed_value_type = ::util::psbt::serialize::Deserialize::deserialize(&$raw_value)?;
+
+                $slf.$keyed_name.insert(key_val, val);
+            }
+        } else {
+            return Err(::util::psbt::Error::InvalidKey($raw_key).into());
+        }
+    };
+}
+
+#[cfg_attr(rustfmt, rustfmt_skip)]
+macro_rules! impl_psbt_get_pair {
+    ($rv:ident.push($slf:ident.$unkeyed_name:ident as <$unkeyed_typeval:expr, _>|<$unkeyed_value_type:ty>)) => {
+        if let Some(ref $unkeyed_name) = $slf.$unkeyed_name {
+            $rv.push(::util::psbt::raw::Pair {
+                key: ::util::psbt::raw::Key {
+                    type_value: $unkeyed_typeval,
+                    key: vec![],
+                },
+                value: ::util::psbt::serialize::Serialize::serialize($unkeyed_name),
+            });
+        }
+    };
+    ($rv:ident.push($slf:ident.$keyed_name:ident as <$keyed_typeval:expr, $keyed_key_type:ty>|<$keyed_value_type:ty>)) => {
+        for (key, val) in &$slf.$keyed_name {
+            $rv.push(::util::psbt::raw::Pair {
+                key: ::util::psbt::raw::Key {
+                    type_value: $keyed_typeval,
+                    key: ::util::psbt::serialize::Serialize::serialize(key),
+                },
+                value: ::util::psbt::serialize::Serialize::serialize(val),
+            });
+        }
+    };
+}

src/util/psbt/map/mod.rs

@@ -16,5 +16,7 @@ pub trait Map {
 
 // place at end to pick up macros
 mod global;
+mod output;
 
 pub use self::global::Global;
+pub use self::output::Output;

src/util/psbt/map/output.rs

@@ -0,0 +1,98 @@
+use std::collections::HashMap;
+
+use blockdata::script::Script;
+use consensus::encode;
+use util::bip32::{DerivationPath, Fingerprint};
+use util::key::PublicKey;
+use util::psbt;
+use util::psbt::map::Map;
+use util::psbt::raw;
+use util::psbt::Error;
+
+/// A key-value map for an output of the corresponding index in the unsigned
+/// transaction.
+#[derive(Clone, Default, Debug, PartialEq)]
+pub struct Output {
+    /// The redeem script for this output.
+    pub redeem_script: Option<Script>,
+    /// The witness script for this output.
+    pub witness_script: Option<Script>,
+    /// A map from public keys needed to spend this output to their
+    /// corresponding master key fingerprints and derivation paths.
+    pub hd_keypaths: HashMap<PublicKey, (Fingerprint, DerivationPath)>,
+    /// Unknown key-value pairs for this output.
+    pub unknown: HashMap<raw::Key, Vec<u8>>,
+}
+
+impl Map for Output {
+    fn insert_pair(&mut self, pair: raw::Pair) -> Result<(), encode::Error> {
+        let raw::Pair {
+            key: raw_key,
+            value: raw_value,
+        } = pair;
+
+        match raw_key.type_value {
+            0u8 => {
+                impl_psbt_insert_pair! {
+                    self.redeem_script <= <raw_key: _>|<raw_value: Script>
+                }
+            }
+            1u8 => {
+                impl_psbt_insert_pair! {
+                    self.witness_script <= <raw_key: _>|<raw_value: Script>
+                }
+            }
+            2u8 => {
+                impl_psbt_insert_pair! {
+                    self.hd_keypaths <= <raw_key: PublicKey>|<raw_value: (Fingerprint, DerivationPath)>
+                }
+            }
+            _ => {
+                if self.unknown.contains_key(&raw_key) {
+                    return Err(Error::DuplicateKey(raw_key).into());
+                } else {
+                    self.unknown.insert(raw_key, raw_value);
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    fn get_pairs(&self) -> Result<Vec<raw::Pair>, encode::Error> {
+        let mut rv: Vec<raw::Pair> = Default::default();
+
+        impl_psbt_get_pair! {
+            rv.push(self.redeem_script as <0u8, _>|<Script>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.witness_script as <1u8, _>|<Script>)
+        }
+
+        impl_psbt_get_pair! {
+            rv.push(self.hd_keypaths as <2u8, PublicKey>|<(Fingerprint, DerivationPath)>)
+        }
+
+        for (key, value) in self.unknown.iter() {
+            rv.push(raw::Pair {
+                key: key.clone(),
+                value: value.clone(),
+            });
+        }
+
+        Ok(rv)
+    }
+
+    fn merge(&mut self, other: Self) -> Result<(), psbt::Error> {
+        self.hd_keypaths.extend(other.hd_keypaths);
+        self.unknown.extend(other.unknown);
+
+        merge!(redeem_script, self, other);
+        merge!(witness_script, self, other);
+
+        Ok(())
+    }
+}
+
+impl_psbtmap_consensus_enc_dec_oding!(Output);

src/util/psbt/mod.rs

@@ -15,19 +15,72 @@ mod macros;
 pub mod serialize;
 
 mod map;
-pub use self::map::{Map, Global};
+pub use self::map::{Map, Global, Output};
 
 #[cfg(test)]
 mod tests {
     use bitcoin_hashes::hex::FromHex;
     use bitcoin_hashes::sha256d;
 
+    use std::collections::HashMap;
+
+    use hex::decode as hex_decode;
+
+    use secp256k1::Secp256k1;
+
     use blockdata::script::Script;
     use blockdata::transaction::{Transaction, TxIn, TxOut, OutPoint};
-    use consensus::encode::{deserialize, serialize};
+    use network::constants::Network::Bitcoin;
-    use util::psbt::map::Global;
+    use consensus::encode::{deserialize, serialize, serialize_hex};
+    use util::bip32::{ChildNumber, DerivationPath, ExtendedPrivKey, ExtendedPubKey, Fingerprint};
+    use util::key::PublicKey;
+    use util::psbt::map::{Global, Output};
     use util::psbt::raw;
 
+    #[test]
+    fn serialize_then_deserialize_output() {
+        let secp = &Secp256k1::new();
+        let seed = hex_decode("000102030405060708090a0b0c0d0e0f").unwrap();
+
+        let mut hd_keypaths: HashMap<PublicKey, (Fingerprint, DerivationPath)> = Default::default();
+
+        let mut sk: ExtendedPrivKey = ExtendedPrivKey::new_master(Bitcoin, &seed).unwrap();
+
+        let fprint: Fingerprint = sk.fingerprint(&secp);
+
+        let dpath: Vec<ChildNumber> = vec![
+            ChildNumber::from_normal_idx(0).unwrap(),
+            ChildNumber::from_normal_idx(1).unwrap(),
+            ChildNumber::from_normal_idx(2).unwrap(),
+            ChildNumber::from_normal_idx(4).unwrap(),
+            ChildNumber::from_normal_idx(42).unwrap(),
+            ChildNumber::from_hardened_idx(69).unwrap(),
+            ChildNumber::from_normal_idx(420).unwrap(),
+            ChildNumber::from_normal_idx(31337).unwrap(),
+        ];
+
+        sk = sk.derive_priv(secp, &dpath).unwrap();
+
+        let pk: ExtendedPubKey = ExtendedPubKey::from_private(&secp, &sk);
+
+        hd_keypaths.insert(pk.public_key, (fprint, dpath.into()));
+
+        let expected: Output = Output {
+            redeem_script: Some(hex_script!(
+                "76a914d0c59903c5bac2868760e90fd521a4665aa7652088ac"
+            )),
+            witness_script: Some(hex_script!(
+                "a9143545e6e33b832c47050f24d3eeb93c9c03948bc787"
+            )),
+            hd_keypaths: hd_keypaths,
+            ..Default::default()
+        };
+
+        let actual: Output = deserialize(&serialize(&expected)).unwrap();
+
+        assert_eq!(expected, actual);
+    }
+
     #[test]
     fn serialize_then_deserialize_global() {
         let expected = Global {

src/util/psbt/serialize.rs

@@ -3,8 +3,14 @@
 //! Defines traits used for (de)serializing PSBT values into/from raw
 //! bytes in PSBT key-value pairs.
 
+use std::io::{self, Cursor};
+
+use blockdata::script::Script;
 use blockdata::transaction::Transaction;
-use consensus::encode;
+use consensus::encode::{self, serialize, Decodable};
+use util::bip32::{ChildNumber, DerivationPath, Fingerprint};
+use util::key::PublicKey;
+use util::psbt;
 
 /// A trait for serializing a value as raw data for insertion into PSBT
 /// key-value pairs.
@@ -20,3 +26,71 @@ pub trait Deserialize: Sized {
 }
 
 impl_psbt_de_serialize!(Transaction);
+
+impl Serialize for Script {
+    fn serialize(&self) -> Vec<u8> {
+        self.to_bytes()
+    }
+}
+
+impl Deserialize for Script {
+    fn deserialize(bytes: &[u8]) -> Result<Self, encode::Error> {
+        Ok(Self::from(bytes.to_vec()))
+    }
+}
+
+impl Serialize for PublicKey {
+    fn serialize(&self) -> Vec<u8> {
+        let mut buf = Vec::new();
+        self.write_into(&mut buf);
+        buf
+    }
+}
+
+impl Deserialize for PublicKey {
+    fn deserialize(bytes: &[u8]) -> Result<Self, encode::Error> {
+        PublicKey::from_slice(bytes)
+            .map_err(|_| encode::Error::ParseFailed("invalid public key"))
+    }
+}
+
+impl Serialize for (Fingerprint, DerivationPath) {
+    fn serialize(&self) -> Vec<u8> {
+        let mut rv: Vec<u8> = Vec::with_capacity(4 + 4 * (self.1).as_ref().len());
+
+        rv.append(&mut self.0.to_bytes().to_vec());
+
+        for cnum in self.1.into_iter() {
+            rv.append(&mut serialize(&u32::from(*cnum)))
+        }
+
+        rv
+    }
+}
+
+impl Deserialize for (Fingerprint, DerivationPath) {
+    fn deserialize(bytes: &[u8]) -> Result<Self, encode::Error> {
+        if bytes.len() < 4 {
+            return Err(io::Error::from(io::ErrorKind::UnexpectedEof).into())
+        }
+
+        let fprint: Fingerprint = Fingerprint::from(&bytes[0..4]);
+        let mut dpath: Vec<ChildNumber> = Default::default();
+
+        let d = &mut Cursor::new(&bytes[4..]);
+        loop {
+            match Decodable::consensus_decode(d) {
+                Ok(index) => {
+                    dpath.push(<ChildNumber as From<u32>>::from(index));
+
+                    if d.position() == (bytes.len() - 4) as u64 {
+                        break;
+                    }
+                },
+                Err(e) => return Err(e),
+            }
+        }
+
+        Ok((fprint, dpath.into()))
+    }
+}