feat: Implement Plutus Data hashing / JSON (#100)

pallas-codec/src/utils.rs

@@ -268,6 +268,12 @@ impl<T> Deref for CborWrap<T> {
 #[derive(Debug)]
 pub struct TagWrap<I, const T: u64>(I);
 
+impl<I, const T: u64> TagWrap<I, T> {
+    pub fn new(inner: I) -> Self {
+        TagWrap(inner)
+    }
+}
+
 impl<'b, I, const T: u64> minicbor::Decode<'b> for TagWrap<I, T>
 where
     I: minicbor::Decode<'b>,

pallas-primitives/src/alonzo/crypto.rs

@@ -1,4 +1,4 @@
-use super::{AuxiliaryData, Header, NativeScript, PlutusData, TransactionBody};
+use super::{AuxiliaryData, Header, NativeScript, PlutusData, PlutusScript, TransactionBody};
 use pallas_crypto::hash::{Hash, Hasher};
 
 pub fn hash_block_header(data: &Header) -> Hash<32> {
@@ -25,6 +25,12 @@ impl NativeScript {
     }
 }
 
+impl PlutusScript {
+    pub fn to_hash(&self) -> Hash<28> {
+        Hasher::<224>::hash_tagged_cbor(self, 1)
+    }
+}
+
 impl PlutusData {
     pub fn to_hash(&self) -> Hash<32> {
         Hasher::<256>::hash_cbor(self)
@@ -41,10 +47,11 @@ impl TransactionBody {
 mod tests {
     use std::str::FromStr;
 
+    use pallas_codec::minicbor::data::Int;
     use pallas_codec::utils::MaybeIndefArray;
     use pallas_crypto::hash::Hash;
 
-    use crate::alonzo::{BlockWrapper, NativeScript};
+    use crate::alonzo::{BigInt, BlockWrapper, Constr, NativeScript, PlutusData};
     use crate::Fragment;
 
     #[test]
@@ -73,7 +80,7 @@ mod tests {
     }
 
     #[test]
-    fn native_script_hashes_cardano_cli() {
+    fn native_script_hashes_as_cardano_cli() {
         // construct an arbitrary script to use as example
         let ns = NativeScript::ScriptAll(MaybeIndefArray::Def(vec![
             NativeScript::ScriptPubkey(
@@ -91,4 +98,45 @@ mod tests {
             Hash::<28>::from_str(cardano_cli_output).unwrap()
         )
     }
+
+    #[test]
+    fn plutus_data_hashes_as_cardano_cli() {
+        // construct an arbitrary complex datum to use as example
+        let pd = PlutusData::Constr(Constr::<PlutusData> {
+            tag: 1280,
+            any_constructor: None,
+            fields: MaybeIndefArray::Indef(vec![
+                PlutusData::BigInt(BigInt::Int(Int::from(4))),
+                PlutusData::Constr(Constr::<PlutusData> {
+                    tag: 124,
+                    any_constructor: None,
+                    fields: MaybeIndefArray::Indef(vec![
+                        PlutusData::BigInt(BigInt::Int(Int::from(-4))),
+                        PlutusData::Constr(Constr::<PlutusData> {
+                            tag: 102,
+                            any_constructor: Some(453),
+                            fields: MaybeIndefArray::Indef(vec![
+                                PlutusData::BigInt(BigInt::Int(Int::from(2))),
+                                PlutusData::BigInt(BigInt::Int(Int::from(3434))),
+                            ]),
+                        }),
+                        PlutusData::BigInt(BigInt::Int(Int::from(-11828293))),
+                    ]),
+                }),
+                PlutusData::BigInt(BigInt::Int(Int::from(11828293))),
+            ]),
+        });
+
+        // if you need to try this out in the cardano-cli, uncomment this line to see
+        // the json representation of the above struct:
+        // println!("{}", crate::ToCanonicalJson::to_json(&pd));
+
+        // hash that we assume correct since it was generated through the cardano-cli
+        let cardano_cli_output = "d9bc0eb6ac664286155f70d720cafd2af16277fbd9014a930997431a2ffbe554";
+
+        assert_eq!(
+            pd.to_hash(),
+            Hash::<32>::from_str(cardano_cli_output).unwrap()
+        )
+    }
 }

pallas-primitives/src/alonzo/json.rs

@@ -2,14 +2,24 @@ use serde_json::json;
 
 use crate::ToCanonicalJson;
 
+impl<A> super::Constr<A> {
+    pub fn constructor_value(&self) -> Option<u64> {
+        match self.tag {
+            121..=127 => Some(self.tag - 121),
+            1280..=1400 => Some(self.tag - 1280 + 7),
+            102 => self.any_constructor,
+            _ => None,
+        }
+    }
+}
+
 // infered from https://github.com/input-output-hk/cardano-node/blob/c1efb2f97134c0607c982246a36e3da7266ac194/cardano-api/src/Cardano/Api/ScriptData.hs#L254
 impl ToCanonicalJson for super::PlutusData {
     fn to_json(&self) -> serde_json::Value {
         match self {
             super::PlutusData::Constr(x) => {
-                let constructor = x.prefix.map(|x| x as u64).unwrap_or(x.tag);
-                let fields: Vec<_> = x.values.iter().map(|i| i.to_json()).collect();
-                json!({ "constructor": constructor, "fields": fields })
+                let fields: Vec<_> = x.fields.iter().map(|i| i.to_json()).collect();
+                json!({ "constructor": x.constructor_value(), "fields": fields })
             }
             super::PlutusData::Map(x) => {
                 let map: Vec<_> = x

pallas-primitives/src/alonzo/model.rs

@@ -908,7 +908,9 @@ impl minicbor::encode::Encode for NativeScript {
     }
 }
 
-pub type PlutusScript = ByteVec;
+#[derive(Encode, Decode, Debug, PartialEq)]
+#[cbor(transparent)]
+pub struct PlutusScript(#[n(0)] ByteVec);
 
 /*
 big_int = int / big_uint / big_nint ; New
@@ -1058,8 +1060,8 @@ impl minicbor::encode::Encode for PlutusData {
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Constr<A> {
     pub tag: u64,
-    pub prefix: Option<u32>,
-    pub values: MaybeIndefArray<A>,
+    pub any_constructor: Option<u64>,
+    pub fields: MaybeIndefArray<A>,
 }
 
 impl<'b, A> minicbor::decode::Decode<'b> for Constr<A>
@@ -1073,17 +1075,16 @@ where
             Tag::Unassigned(x) => match x {
                 121..=127 | 1280..=1400 => Ok(Constr {
                     tag: x,
-                    values: d.decode()?,
-                    prefix: None,
+                    fields: d.decode()?,
+                    any_constructor: None,
                 }),
                 102 => {
                     d.array()?;
-                    let prefix = Some(d.decode()?);
-                    let values = d.decode()?;
+
                     Ok(Constr {
-                        tag: 102,
-                        prefix,
-                        values,
+                        tag: x,
+                        any_constructor: Some(d.decode()?),
+                        fields: d.decode()?,
                     })
                 }
                 _ => Err(minicbor::decode::Error::message(
@@ -1110,13 +1111,13 @@ where
         match self.tag {
             102 => {
                 e.array(2)?;
-                e.encode(self.prefix)?;
-                e.encode(&self.values)?;
+                e.encode(self.any_constructor.unwrap_or_default())?;
+                e.encode(&self.fields)?;
 
                 Ok(())
             }
             _ => {
-                e.encode(&self.values)?;
+                e.encode(&self.fields)?;
 
                 Ok(())
             }