feat(traverse): Add tx input traversing (#121)

Co-authored-by: Mateusz Czeladka <mateusz.szczap[at]gmail.com>

pallas-traverse/src/input.rs

@@ -0,0 +1,29 @@
+use std::borrow::Cow;
+
+use pallas_primitives::{alonzo, byron};
+
+use crate::MultiEraInput;
+
+impl<'b> MultiEraInput<'b> {
+    pub fn from_byron(input: &'b byron::TxIn) -> Self {
+        Self::Byron(Box::new(Cow::Borrowed(input)))
+    }
+
+    pub fn from_alonzo_compatible(input: &'b alonzo::TransactionInput) -> Self {
+        Self::AlonzoCompatible(Box::new(Cow::Borrowed(input)))
+    }
+
+    pub fn as_alonzo(&self) -> Option<&alonzo::TransactionInput> {
+        match self {
+            MultiEraInput::Byron(_) => None,
+            MultiEraInput::AlonzoCompatible(x) => Some(x),
+        }
+    }
+
+    pub fn as_byron(&self) -> Option<&byron::TxIn> {
+        match self {
+            MultiEraInput::Byron(x) => Some(x),
+            MultiEraInput::AlonzoCompatible(_) => None,
+        }
+    }
+}

pallas-traverse/src/lib.rs

@@ -10,6 +10,7 @@ pub mod block;
 pub mod cert;
 pub mod era;
 pub mod output;
+pub mod input;
 pub mod probe;
 mod support;
 pub mod tx;
@@ -55,6 +56,13 @@ pub enum MultiEraOutput<'b> {
     AlonzoCompatible(Box<Cow<'b, alonzo::TransactionOutput>>),
 }
 
+#[derive(Debug)]
+#[non_exhaustive]
+pub enum MultiEraInput<'b> {
+    Byron(Box<Cow<'b, byron::TxIn>>),
+    AlonzoCompatible(Box<Cow<'b, alonzo::TransactionInput>>),
+}
+
 pub enum MultiEraCert<'b> {
     NotApplicable,
     AlonzoCompatible(Box<Cow<'b, alonzo::Certificate>>),

pallas-traverse/src/tx.rs

@@ -3,7 +3,7 @@ use pallas_crypto::hash::Hash;
 use pallas_primitives::{alonzo, byron, ToHash};
 use std::borrow::Cow;
 
-use crate::{MultiEraCert, MultiEraOutput, MultiEraTx};
+use crate::{MultiEraCert, MultiEraOutput, MultiEraInput, MultiEraTx};
 
 impl<'b> MultiEraTx<'b> {
     pub fn from_byron(tx: &'b byron::MintedTxPayload<'b>) -> Self {
@@ -45,6 +45,24 @@ impl<'b> MultiEraTx<'b> {
         }
     }
 
+    pub fn inputs(&self) -> Vec<MultiEraInput> {
+        match self {
+            MultiEraTx::AlonzoCompatible(x) => x
+                .transaction_body
+                .inputs
+                .iter()
+                .map(MultiEraInput::from_alonzo_compatible)
+                .collect(),
+
+            MultiEraTx::Byron(x) => x
+                .transaction
+                .inputs
+                .iter()
+                .map(MultiEraInput::from_byron)
+                .collect(),
+        }
+    }
+
     pub fn certs(&self) -> Vec<MultiEraCert> {
         match self {
             MultiEraTx::AlonzoCompatible(x) => x