iface: add ContractIface::outputs_typed method

src/interface/contract.rs

@@ -22,12 +22,13 @@
 use std::borrow::Borrow;
 use std::collections::{BTreeSet, HashMap, HashSet};
 
+use amplify::Wrapper;
 use rgb::validation::Scripts;
 use rgb::{
     AssignmentType, AttachId, ContractId, OpId, Opout, Schema, State, StateData, XOutputSeal,
     XWitnessId, STATE_DATA_MAX_LEN,
 };
-use strict_encoding::{FieldName, SerializeError};
+use strict_encoding::{FieldName, SerializeError, StrictDeserialize};
 use strict_types::{typify, SemId, StrictVal, TypeSystem};
 
 use crate::contract::{Allocation, WitnessInfo};
@@ -58,14 +59,27 @@ pub enum ContractError {
     derive(Serialize, Deserialize),
     serde(crate = "serde_crate", rename_all = "camelCase")
 )]
-pub struct Output {
+pub struct Output<T = StrictVal> {
     pub opout: Opout,
     pub seal: XOutputSeal,
-    pub state: StrictVal,
+    pub state: T,
     pub attach_id: Option<AttachId>,
     pub witness: Option<XWitnessId>,
 }
 
+impl<T: StrictDeserialize> From<Allocation> for Output<T> {
+    fn from(a: Allocation) -> Self {
+        Output {
+            opout: a.opout,
+            seal: a.seal,
+            state: T::from_strict_serialized(a.state.data.to_inner())
+                .expect("data in stash are not valid"),
+            attach_id: a.state.attach,
+            witness: a.witness,
+        }
+    }
+}
+
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug, Display)]
 #[cfg_attr(
     feature = "serde",
@@ -286,6 +300,19 @@ impl<S: ContractStateRead> ContractIface<S> {
             .map(|a| self.allocation_to_output(a)))
     }
 
+    pub fn outputs_typed<'c, T: StrictDeserialize + 'c>(
+        &'c self,
+        name: impl Into<FieldName>,
+        filter: impl AssignmentsFilter + 'c,
+    ) -> Result<impl Iterator<Item = Output<T>> + 'c, ContractError> {
+        let type_id = self.assignment_type(name)?;
+        Ok(self
+            .allocations(filter)
+            .filter(move |a| a.opout.ty == type_id)
+            .cloned()
+            .map(Output::from))
+    }
+
     pub fn history(
         &self,
         filter_outpoints: impl AssignmentsFilter,