From 61d533aad7d6e8fc80dd6624744d24e305c83d34 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Bylica?= <chfast@gmail.com>
Date: Fri, 22 Sep 2017 18:50:20 +0200
Subject: [PATCH] EVM-C: Move ABI version from factory to instance

---
 examples/capi.c      |  6 +++---
 examples/examplevm.c | 12 ++++++++----
 include/evm.h        | 12 +++++++-----
 3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/examples/capi.c b/examples/capi.c
index 7a67c45..a8092f7 100644
--- a/examples/capi.c
+++ b/examples/capi.c
@@ -128,10 +128,10 @@ static const struct evm_host example_host = {
 /// 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(&example_host);
+    struct evm_instance* jit = factory.create();
+    if (jit->abi_version != EVM_ABI_VERSION)
+        return 1;  // Incompatible ABI version.
 
     uint8_t const code[] = "Place some EVM bytecode here";
     const size_t code_size = sizeof(code);
diff --git a/examples/examplevm.c b/examples/examplevm.c
index 7840db0..1f938b7 100644
--- a/examples/examplevm.c
+++ b/examples/examplevm.c
@@ -112,17 +112,21 @@ static struct evm_result execute(struct evm_instance* instance,
 
 static struct evm_instance* evm_create(const struct evm_host* host)
 {
+    struct evm_instance init = {
+        .abi_version = EVM_ABI_VERSION,
+        .destroy = evm_destroy,
+        .execute = execute,
+        .set_option = evm_set_option
+    };
     struct examplevm* vm = calloc(1, sizeof(struct examplevm));
     struct evm_instance* interface = &vm->instance;
-    interface->destroy = evm_destroy;
-    interface->execute = execute;
-    interface->set_option = evm_set_option;
+    memcpy(interface, &init, sizeof(init));
     vm->host = host;
     return interface;
 }
 
 struct evm_factory examplevm_get_factory()
 {
-    struct evm_factory factory = {EVM_ABI_VERSION, evm_create};
+    struct evm_factory factory = {evm_create};
     return factory;
 }
diff --git a/include/evm.h b/include/evm.h
index 406e020..acf30d9 100644
--- a/include/evm.h
+++ b/include/evm.h
@@ -437,6 +437,13 @@ typedef void (*evm_prepare_code_fn)(struct evm_instance* instance,
 ///
 /// Defines the base struct of the EVM implementation.
 struct evm_instance {
+
+    /// EVM-C ABI version implemented by the EVM instance.
+    ///
+    /// For future use to detect ABI incompatibilities. The EVM-C ABI version
+    /// represented by this file is in ::EVM_ABI_VERSION.
+    const int abi_version;
+
     /// Pointer to function destroying the EVM instance.
     evm_destroy_fn destroy;
 
@@ -463,11 +470,6 @@ struct evm_instance {
 ///
 /// Provides ABI protection and method to create an EVM instance.
 struct evm_factory {
-    /// EVM-C ABI version implemented by the EVM factory and instance.
-    ///
-    /// For future use to detect ABI incompatibilities. The EVM-C ABI version
-    /// represented by this file is in ::EVM_ABI_VERSION.
-    int abi_version;
 
     /// Pointer to function creating and initializing the EVM instance.
     evm_create_fn create;