Merge rust-bitcoin/rust-miniscript#434: Add Hash256 associated type

905c5dc2728479501aa59097f902fba5ad846737 Rename Pk::Hash to Pk::RawPkHash (sanket1729)
5d36f9bd253c262bbf24973150bfd5dda598d1b1 Add Hash256 associated type (sanket1729)
e22b081b809ae9564e340b87b5baeefc4b0e02e6 Add Hash256 type (sanket1729)

Pull request description:

  - Implement a new hash type that does not display/FromStr with `DISPLAY_BACKWARD`. Should we make this type upstream in bitcoin-hashes?
  - Remove the PkTranslator trait as it was causing conflicting implementations downstream.
  - Replace the above with more macros :(

ACKs for top commit:
  apoelstra:
    ACK 905c5dc2728479501aa59097f902fba5ad846737

Tree-SHA512: c65027ce30a917e96d9403fcc75dae3089ec4f0ffa169fdfda8b559aa33345dfff2cf89ed49a26376de23d5acc31cbdaeb00dc31f9a000b89c18b25e58e938d4

Author: heap-coder

examples/taproot.rs

@@ -6,7 +6,7 @@ use bitcoin::util::address::WitnessVersion;
 use bitcoin::Network;
 use miniscript::descriptor::DescriptorType;
 use miniscript::policy::Concrete;
-use miniscript::{Descriptor, Miniscript, Tap, TranslatePk, Translator};
+use miniscript::{hash256, Descriptor, Miniscript, Tap, TranslatePk, Translator};
 use secp256k1::{rand, KeyPair};
 
 // Refer to https://github.com/sanket1729/adv_btc_workshop/blob/master/workshop.md#creating-a-taproot-descriptor
@@ -28,6 +28,10 @@ impl Translator<String, bitcoin::XOnlyPublicKey, ()> for StrPkTranslator {
     fn sha256(&mut self, _sha256: &String) -> Result<sha256::Hash, ()> {
         unreachable!("Policy does not contain any sha256 fragment");
     }
+
+    fn hash256(&mut self, _sha256: &String) -> Result<hash256::Hash, ()> {
+        unreachable!("Policy does not contain any hash256 fragment");
+    }
 }
 
 fn main() {

src/descriptor/bare.rs

@@ -167,7 +167,7 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Bare<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         self.ms.for_each_key(pred)
     }
@@ -329,7 +329,7 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Pkh<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, mut pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         pred(&self.pk)
     }

src/descriptor/key.rs

@@ -10,7 +10,7 @@ use bitcoin::util::bip32;
 use bitcoin::{self, XOnlyPublicKey, XpubIdentifier};
 
 use crate::prelude::*;
-use crate::{MiniscriptKey, ToPublicKey};
+use crate::{hash256, MiniscriptKey, ToPublicKey};
 
 /// The descriptor pubkey, either a single pubkey or an xpub.
 #[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash)]
@@ -736,8 +736,9 @@ impl<K: InnerXKey> DescriptorXKey<K> {
 
 impl MiniscriptKey for DescriptorPublicKey {
     // This allows us to be able to derive public keys even for PkH s
-    type Hash = Self;
-    type Sha256 = bitcoin::hashes::sha256::Hash;
+    type RawPkHash = Self;
+    type Sha256 = sha256::Hash;
+    type Hash256 = hash256::Hash;
 
     fn is_uncompressed(&self) -> bool {
         match self {
@@ -802,8 +803,9 @@ impl fmt::Display for DerivedDescriptorKey {
 
 impl MiniscriptKey for DerivedDescriptorKey {
     // This allows us to be able to derive public keys even for PkH s
-    type Hash = Self;
-    type Sha256 = bitcoin::hashes::sha256::Hash;
+    type RawPkHash = Self;
+    type Sha256 = sha256::Hash;
+    type Hash256 = hash256::Hash;
 
     fn is_uncompressed(&self) -> bool {
         self.key.is_uncompressed()
@@ -831,6 +833,10 @@ impl ToPublicKey for DerivedDescriptorKey {
     fn to_sha256(hash: &sha256::Hash) -> sha256::Hash {
         *hash
     }
+
+    fn to_hash256(hash: &hash256::Hash) -> hash256::Hash {
+        *hash
+    }
 }
 
 #[cfg(test)]

src/descriptor/mod.rs

@@ -37,8 +37,8 @@ use self::checksum::verify_checksum;
 use crate::miniscript::{Legacy, Miniscript, Segwitv0};
 use crate::prelude::*;
 use crate::{
-    expression, miniscript, BareCtx, Error, ForEachKey, MiniscriptKey, PkTranslator, Satisfier,
-    ToPublicKey, TranslatePk, Translator,
+    expression, hash256, miniscript, BareCtx, Error, ForEachKey, MiniscriptKey, PkTranslator,
+    Satisfier, ToPublicKey, TranslatePk, Translator,
 };
 
 mod bare;
@@ -498,7 +498,7 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Descriptor<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         match *self {
             Descriptor::Bare(ref bare) => bare.for_each_key(pred),
@@ -646,6 +646,12 @@ impl Descriptor<DescriptorPublicKey> {
                     sha256::Hash::from_str(sha256).map_err(|e| Error::Unexpected(e.to_string()))?;
                 Ok(hash)
             }
+
+            fn hash256(&mut self, hash256: &String) -> Result<hash256::Hash, Error> {
+                let hash = hash256::Hash::from_str(hash256)
+                    .map_err(|e| Error::Unexpected(e.to_string()))?;
+                Ok(hash)
+            }
         }
 
         let descriptor = Descriptor::<String>::from_str(s)?;
@@ -672,6 +678,10 @@ impl Descriptor<DescriptorPublicKey> {
             fn sha256(&mut self, sha256: &sha256::Hash) -> Result<String, ()> {
                 Ok(sha256.to_string())
             }
+
+            fn hash256(&mut self, hash256: &hash256::Hash) -> Result<String, ()> {
+                Ok(hash256.to_string())
+            }
         }
 
         fn key_to_string(pk: &DescriptorPublicKey, key_map: &KeyMap) -> Result<String, ()> {

src/descriptor/segwitv0.rs

@@ -249,7 +249,7 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Wsh<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         match self.inner {
             WshInner::SortedMulti(ref smv) => smv.for_each_key(pred),
@@ -442,7 +442,7 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Wpkh<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, mut pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         pred(&self.pk)
     }

src/descriptor/sh.rs

@@ -380,7 +380,7 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Sh<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         match self.inner {
             ShInner::Wsh(ref wsh) => wsh.for_each_key(pred),

src/descriptor/sortedmulti.rs

@@ -115,7 +115,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> ForEachKey<Pk> for SortedMultiVec<Pk
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, mut pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         self.pks.iter().all(|key| pred(key))
     }

src/descriptor/tr.rs

@@ -581,7 +581,7 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Tr<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, mut pred: F) -> bool
     where
         Pk: 'a,
-        Pk::Hash: 'a,
+        Pk::RawPkHash: 'a,
     {
         let script_keys_res = self
             .iter_scripts()

src/interpreter/mod.rs

@@ -23,14 +23,14 @@ use core::fmt;
 use core::str::FromStr;
 
 use bitcoin::blockdata::witness::Witness;
-use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d};
+use bitcoin::hashes::{hash160, ripemd160, sha256};
 use bitcoin::util::{sighash, taproot};
 use bitcoin::{self, secp256k1, TxOut};
 
 use crate::miniscript::context::NoChecks;
 use crate::miniscript::ScriptContext;
 use crate::prelude::*;
-use crate::{Descriptor, Miniscript, Terminal, ToPublicKey};
+use crate::{hash256, Descriptor, Miniscript, Terminal, ToPublicKey};
 
 mod error;
 mod inner;
@@ -148,10 +148,11 @@ impl TypedHash160 {
 }
 
 impl MiniscriptKey for BitcoinKey {
-    type Hash = TypedHash160;
-    type Sha256 = bitcoin::hashes::sha256::Hash;
+    type RawPkHash = TypedHash160;
+    type Sha256 = sha256::Hash;
+    type Hash256 = hash256::Hash;
 
-    fn to_pubkeyhash(&self) -> Self::Hash {
+    fn to_pubkeyhash(&self) -> Self::RawPkHash {
         match self {
             BitcoinKey::Fullkey(pk) => TypedHash160::FullKey(pk.to_pubkeyhash()),
             BitcoinKey::XOnlyPublicKey(pk) => TypedHash160::XonlyKey(pk.to_pubkeyhash()),
@@ -454,7 +455,7 @@ pub enum HashLockType {
     ///SHA 256 hashlock
     Sha256(sha256::Hash),
     ///Hash 256 hashlock
-    Hash256(sha256d::Hash),
+    Hash256(hash256::Hash),
     ///Hash160 hashlock
     Hash160(hash160::Hash),
     ///Ripemd160 hashlock
@@ -1040,7 +1041,7 @@ fn verify_sersig<'txin>(
 mod tests {
 
     use bitcoin;
-    use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d, Hash};
+    use bitcoin::hashes::{hash160, ripemd160, sha256, Hash};
     use bitcoin::secp256k1::{self, Secp256k1};
 
     use super::inner::ToNoChecks;
@@ -1156,11 +1157,8 @@ mod tests {
         let preimage = [0xab as u8; 32];
         let sha256_hash = sha256::Hash::hash(&preimage);
         let sha256 = no_checks_ms(&format!("sha256({})", sha256_hash));
-        let sha256d_hash_rev = sha256d::Hash::hash(&preimage);
-        let mut sha256d_hash_bytes = sha256d_hash_rev.clone().into_inner();
-        sha256d_hash_bytes.reverse();
-        let sha256d_hash = sha256d::Hash::from_inner(sha256d_hash_bytes);
-        let hash256 = no_checks_ms(&format!("hash256({})", sha256d_hash));
+        let hash256_hash = hash256::Hash::hash(&preimage);
+        let hash256 = no_checks_ms(&format!("hash256({})", hash256_hash));
         let hash160_hash = hash160::Hash::hash(&preimage);
         let hash160 = no_checks_ms(&format!("hash160({})", hash160_hash));
         let ripemd160_hash = ripemd160::Hash::hash(&preimage);
@@ -1242,7 +1240,7 @@ mod tests {
         assert_eq!(
             sha256d_satisfied.unwrap(),
             vec![SatisfiedConstraint::HashLock {
-                hash: HashLockType::Hash256(sha256d_hash_rev),
+                hash: HashLockType::Hash256(hash256_hash),
                 preimage: preimage,
             }]
         );

src/interpreter/stack.rs

@@ -16,12 +16,13 @@
 
 use bitcoin;
 use bitcoin::blockdata::{opcodes, script};
-use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d, Hash};
+use bitcoin::hashes::{hash160, ripemd160, sha256, Hash};
 
 use super::error::PkEvalErrInner;
 use super::{
     verify_sersig, BitcoinKey, Error, HashLockType, KeySigPair, SatisfiedConstraint, TypedHash160,
 };
+use crate::hash256;
 use crate::prelude::*;
 
 /// Definition of Stack Element of the Stack used for interpretation of Miniscript.
@@ -288,13 +289,13 @@ impl<'txin> Stack<'txin> {
     /// `SIZE 32 EQUALVERIFY HASH256 h EQUAL`
     pub(super) fn evaluate_hash256(
         &mut self,
-        hash: &sha256d::Hash,
+        hash: &hash256::Hash,
     ) -> Option<Result<SatisfiedConstraint, Error>> {
         if let Some(Element::Push(preimage)) = self.pop() {
             if preimage.len() != 32 {
                 return Some(Err(Error::HashPreimageLengthMismatch));
             }
-            if sha256d::Hash::hash(preimage) == *hash {
+            if hash256::Hash::hash(preimage) == *hash {
                 self.push(Element::Satisfied);
                 Some(Ok(SatisfiedConstraint::HashLock {
                     hash: HashLockType::Hash256(*hash),