support for decoding destexecdata

pkg/reader/ccip.go

@@ -367,11 +367,22 @@ func (r *ccipChainReader) MsgsBetweenSeqNums(
 			return nil, fmt.Errorf("failed to cast %v to Message", item.Data)
 		}
 
-		msg.Message.ExtraArgsDecoded, err = r.extraDataCodec.DecodeExtraData(msg.Message.ExtraArgs, sourceChainSelector)
+		msg.Message.ExtraArgsDecoded, err = r.extraDataCodec.DecodeExtraArgs(msg.Message.ExtraArgs, sourceChainSelector)
 		if err != nil {
 			return nil, fmt.Errorf("failed to decode ExtraArgs: %w", err)
 		}
 		msg.Message.Header.OnRamp = onRampAddress
+
+		for i, tokenAmount := range msg.Message.TokenAmounts {
+			tokenAmount.DestExecData, err = r.extraDataCodec.DecodeTokenAmountDestExecData(
+				tokenAmount.DestExecData,
+				sourceChainSelector,
+			)
+			if err != nil {
+				return nil, fmt.Errorf("failed to decode token amount destExecData (%v): %w", tokenAmount.DestExecData, err)
+			}
+			msg.Message.TokenAmounts[i] = tokenAmount
+		}
 		msgs = append(msgs, msg.Message)
 	}
 

pkg/types/ccipocr3/interfaces.go

@@ -21,7 +21,10 @@ type MessageHasher interface {
 }
 
 type ExtraDataCodec interface {
-	DecodeExtraData(ExtraArgs Bytes, sourceChainSelector ChainSelector) (map[string]any, error)
+	// DecodeExtraArgs reformat bytes into a chain agnostic map[string]any representation for extra args
+	DecodeExtraArgs(extraArgs Bytes, sourceChainSelector ChainSelector) (map[string]any, error)
+	// DecodeTokenAmountDestExecData provide special treatment for DestExecData in token message depends on source chain
+	DecodeTokenAmountDestExecData(destExecData Bytes, sourceChainSelector ChainSelector) (Bytes, error)
 }
 
 // RMNCrypto provides a chain-agnostic interface for verifying RMN signatures.