Merge rust-bitcoin#2715: psbt: Use macro to hash instead of relying o…

…n `Hash` trait

9e4b092 psbt: Use macro instead of function (Tobin C. Harding)

Pull request description:

  We have a private function that makes use of the `Hash` trait to generically hash map entries. This usage makes patching the `hashes` module difficult. We can achieve the same thing by using a macro and passing in the concrete type.

  This is an internal change, no effect on logic or public API.

ACKs for top commit:
  apoelstra:
    ACK 9e4b092

Tree-SHA512: 8b788fa91d21bbae556c746c2e55e6e9395e022bedf13193555ef7482109b6ef5032b233c5f37543a31ebda49d9b4761c161ca0db501472047eb661a48e944b7

bitcoin/src/psbt/macros.rs

@@ -111,6 +111,30 @@ macro_rules! impl_psbt_insert_pair {
     };
 }
 
+#[rustfmt::skip]
+macro_rules! psbt_insert_hash_pair {
+    (&mut $slf:ident.$map:ident <= $raw_key:ident|$raw_value:ident|$hash:path|$hash_type_error:path) => {
+        if $raw_key.key.is_empty() {
+            return Err(psbt::Error::InvalidKey($raw_key));
+        }
+        let key_val: $hash = Deserialize::deserialize(&$raw_key.key)?;
+        match $slf.$map.entry(key_val) {
+            btree_map::Entry::Vacant(empty_key) => {
+                let val: Vec<u8> = Deserialize::deserialize(&$raw_value)?;
+                if <$hash as hashes::Hash>::hash(&val) != key_val {
+                    return Err(psbt::Error::InvalidPreimageHashPair {
+                        preimage: val.into_boxed_slice(),
+                        hash: Box::from(key_val.borrow()),
+                        hash_type: $hash_type_error,
+                    });
+                }
+                empty_key.insert(val);
+            }
+            btree_map::Entry::Occupied(_) => return Err(psbt::Error::DuplicateKey($raw_key)),
+        }
+    }
+}
+
 #[rustfmt::skip]
 macro_rules! impl_psbt_get_pair {
     ($rv:ident.push($slf:ident.$unkeyed_name:ident, $unkeyed_typeval:ident)) => {

bitcoin/src/psbt/map/input.rs

@@ -300,36 +300,24 @@ impl Input {
                 }
             }
             PSBT_IN_RIPEMD160 => {
-                psbt_insert_hash_pair(
-                    &mut self.ripemd160_preimages,
-                    raw_key,
-                    raw_value,
-                    error::PsbtHash::Ripemd,
-                )?;
+                psbt_insert_hash_pair! {
+                    &mut self.ripemd160_preimages <= raw_key|raw_value|ripemd160::Hash|error::PsbtHash::Ripemd
+                }
             }
             PSBT_IN_SHA256 => {
-                psbt_insert_hash_pair(
-                    &mut self.sha256_preimages,
-                    raw_key,
-                    raw_value,
-                    error::PsbtHash::Sha256,
-                )?;
+                psbt_insert_hash_pair! {
+                    &mut self.sha256_preimages <= raw_key|raw_value|sha256::Hash|error::PsbtHash::Sha256
+                }
             }
             PSBT_IN_HASH160 => {
-                psbt_insert_hash_pair(
-                    &mut self.hash160_preimages,
-                    raw_key,
-                    raw_value,
-                    error::PsbtHash::Hash160,
-                )?;
+                psbt_insert_hash_pair! {
+                    &mut self.hash160_preimages <= raw_key|raw_value|hash160::Hash|error::PsbtHash::Hash160
+                }
             }
             PSBT_IN_HASH256 => {
-                psbt_insert_hash_pair(
-                    &mut self.hash256_preimages,
-                    raw_key,
-                    raw_value,
-                    error::PsbtHash::Hash256,
-                )?;
+                psbt_insert_hash_pair! {
+                    &mut self.hash256_preimages <= raw_key|raw_value|sha256d::Hash|error::PsbtHash::Hash256
+                }
             }
             PSBT_IN_TAP_KEY_SIG => {
                 impl_psbt_insert_pair! {
@@ -505,36 +493,6 @@ impl Map for Input {
 
 impl_psbtmap_ser_de_serialize!(Input);
 
-fn psbt_insert_hash_pair<H>(
-    map: &mut BTreeMap<H, Vec<u8>>,
-    raw_key: raw::Key,
-    raw_value: Vec<u8>,
-    hash_type: error::PsbtHash,
-) -> Result<(), Error>
-where
-    H: hashes::Hash + Deserialize,
-{
-    if raw_key.key.is_empty() {
-        return Err(psbt::Error::InvalidKey(raw_key));
-    }
-    let key_val: H = Deserialize::deserialize(&raw_key.key)?;
-    match map.entry(key_val) {
-        btree_map::Entry::Vacant(empty_key) => {
-            let val: Vec<u8> = Deserialize::deserialize(&raw_value)?;
-            if <H as hashes::Hash>::hash(&val) != key_val {
-                return Err(psbt::Error::InvalidPreimageHashPair {
-                    preimage: val.into_boxed_slice(),
-                    hash: Box::from(key_val.as_ref()),
-                    hash_type,
-                });
-            }
-            empty_key.insert(val);
-            Ok(())
-        }
-        btree_map::Entry::Occupied(_) => Err(psbt::Error::DuplicateKey(raw_key)),
-    }
-}
-
 #[cfg(test)]
 mod test {
     use super::*;