EVM-C: Fix C examples

examples/capi.c

@@ -22,16 +22,17 @@ static void query(union evm_variant* result,
                   const union evm_variant* arg) {
     printf("EVM-C: QUERY %d\n", key);
     switch (key) {
-    case EVM_GAS_LIMIT:
-        result->int64 = 314;
+    case EVM_CODE_BY_ADDRESS:
+        result->data = NULL;
+        result->data_size = 0;
         break;
 
     case EVM_BALANCE:
         result->uint256be = balance(env, arg->address);
         break;
 
-    case EVM_ADDRESS:
-        result->address = address(env);
+    case EVM_ACCOUNT_EXISTS:
+        result->int64 = 0;
         break;
 
     default:
@@ -63,13 +64,19 @@ static int64_t call(
     return EVM_CALL_FAILURE;
 }
 
+static void get_tx_context(struct evm_tx_context* result, struct evm_env* env)
+{
+
+}
+
 /// Example how the API is supposed to be used.
 int main(int argc, char *argv[]) {
     struct evm_factory factory = examplevm_get_factory();
     if (factory.abi_version != EVM_ABI_VERSION)
         return 1;  // Incompatible ABI version.
 
-    struct evm_instance* jit = factory.create(query, update, call);
+    struct evm_instance* jit = factory.create(query, update, call,
+                                              get_tx_context);
 
     uint8_t const code[] = "Place some EVM bytecode here";
     const size_t code_size = sizeof(code);

examples/examplevm.c

@@ -9,6 +9,7 @@ struct examplevm
     evm_query_fn query_fn;
     evm_update_fn update_fn;
     evm_call_fn call_fn;
+    evm_get_tx_context_fn get_tx_context_fn;
 };
 
 static void evm_destroy(struct evm_instance* evm)
@@ -93,7 +94,8 @@ static struct evm_result evm_execute(struct evm_instance* instance,
 
 static struct evm_instance* evm_create(evm_query_fn query_fn,
                                        evm_update_fn update_fn,
-                                       evm_call_fn call_fn)
+                                       evm_call_fn call_fn,
+                                       evm_get_tx_context_fn get_tx_context_fn)
 {
     struct examplevm* vm = calloc(1, sizeof(struct examplevm));
     struct evm_instance* interface = &vm->instance;
@@ -103,6 +105,7 @@ static struct evm_instance* evm_create(evm_query_fn query_fn,
     vm->query_fn = query_fn;
     vm->update_fn = update_fn;
     vm->call_fn = call_fn;
+    vm->get_tx_context_fn = get_tx_context_fn;
     return interface;
 }
 

include/evm.h

@@ -29,6 +29,10 @@ enum {
     EVM_ABI_VERSION = 0
 };
 
+/// Opaque struct representing execution enviroment managed by the host
+/// application.
+struct evm_env;
+
 /// Big-endian 256-bit integer.
 ///
 /// 32 bytes of data representing big-endian 256-bit integer. I.e. bytes[0] is
@@ -169,10 +173,6 @@ enum evm_query_key {
 };
 
 
-/// Opaque struct representing execution enviroment managed by the host
-/// application.
-struct evm_env;
-
 /// Variant type to represent possible types of values used in EVM.
 ///
 /// Type-safety is lost around the code that uses this type. We should have