feat: works

__crypto/simple_contract/src/engine.rs

@@ -0,0 +1,26 @@
+use rust_util::{XResult, simple_error};
+use crate::{engine_credit::ContractEngineCredit, tx::Transaction};
+
+pub struct ContractEngine {
+}
+
+impl ContractEngine {
+    pub fn new() -> Self {
+        Self{}
+    }
+
+    pub fn execute(&self, tx: &Transaction) -> XResult<()> {
+        tx.verify()?;
+
+        let tx_body = tx.parse_body()?;
+
+        match tx_body.contract.as_str() {
+            "credit" => {
+                ContractEngineCredit::new().execute(tx, &tx_body)?;
+            },
+            c => return simple_error!("Unknown cotract: {}", c),
+        }
+        
+        Ok(())
+    }
+}