txe

yarn-project/txe/src/oracle/txe_oracle.ts

@@ -82,6 +82,8 @@ export class TXE implements TypedOracle {
   private msgSender: AztecAddress;
   private functionSelector = FunctionSelector.fromField(new Fr(0));
   private isStaticCall = false;
+  // Return/revert data of the latest nested call.
+  private nestedCallReturndata: Fr[] = [];
 
   private contractDataOracle: ContractDataOracle;
 
@@ -801,6 +803,8 @@ export class TXE implements TypedOracle {
     );
 
     const executionResult = await this.executePublicFunction(args, callContext, this.sideEffectsCounter);
+    // Save return/revert data for later.
+    this.nestedCallReturndata = executionResult.returnValues;
 
     // Apply side effects
     if (!executionResult.reverted) {
@@ -822,6 +826,14 @@ export class TXE implements TypedOracle {
     return executionResult;
   }
 
+  avmOpcodeReturndataSize(): number {
+    return this.nestedCallReturndata.length;
+  }
+
+  avmOpcodeReturndataCopy(rdOffset: number, copySize: number): Fr[] {
+    return this.nestedCallReturndata.slice(rdOffset, rdOffset + copySize);
+  }
+
   async avmOpcodeNullifierExists(innerNullifier: Fr, targetAddress: AztecAddress): Promise<boolean> {
     const nullifier = siloNullifier(targetAddress, innerNullifier!);
     const db = await this.trees.getLatest();

yarn-project/txe/src/txe_service/txe_service.ts

@@ -711,6 +711,20 @@ export class TXEService {
     return toForeignCallResult([toSingle(version)]);
   }
 
+  avmOpcodeReturndataSize() {
+    const size = (this.typedOracle as TXE).avmOpcodeReturndataSize();
+    return toForeignCallResult([toSingle(new Fr(size))]);
+  }
+
+  avmOpcodeReturndataCopy(rdOffset: ForeignCallSingle, copySize: ForeignCallSingle) {
+    const returndata = (this.typedOracle as TXE).avmOpcodeReturndataCopy(
+      fromSingle(rdOffset).toNumber(),
+      fromSingle(copySize).toNumber(),
+    );
+    // This is a slice, so we need to return the length as well.
+    return toForeignCallResult([toSingle(new Fr(returndata.length)), toArray(returndata)]);
+  }
+
   async avmOpcodeCall(
     _gas: ForeignCallArray,
     address: ForeignCallSingle,