rust: use evmc c loader replace pure rust version

bindings/rust/evmc-client/Cargo.toml

@@ -10,9 +10,14 @@ license = "Apache-2.0"
 repository = "https://github.com/ethereum/evmc"
 description = "Bindings to EVMC (Client/Host specific)"
 edition = "2018"
+build = "build.rs"
 
 [dependencies]
-evmc-sys = { path = "../evmc-sys", version = "7.4.0" }
-evmc-vm = { path = "../evmc-vm", version = "7.4.0" }
-libloading = "0.5"
+evmc-sys = { path = "../evmc-sys" }
+evmc-vm = { path = "../evmc-vm" }
+enum_primitive = "0.1.1"
+num = "0.3"
 lazy_static = "1.4.0"
+
+[build-dependencies]
+cmake = "0.1.44"

bindings/rust/evmc-client/build.rs

@@ -0,0 +1,30 @@
+// Copyright (C) 2020 Second State.
+// This file is part of EVMC-Client.
+
+// EVMC-Client is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+
+// EVMC-Client is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use std::path::Path;
+extern crate cmake;
+use cmake::Config;
+
+fn build_link_evmc_tools() {
+    let dst = Config::new("../../../").build();
+    let evmc_path = Path::new(&dst).join("build/lib/loader");
+    println!("cargo:rustc-link-search=native={}", evmc_path.display());
+    println!("cargo:rustc-link-lib=static=evmc-loader");
+}
+
+fn main() {
+    build_link_evmc_tools();
+}

bindings/rust/evmc-client/src/lib.rs

@@ -3,11 +3,12 @@
  * Licensed under the Apache License, Version 2.0.
  */
 
+#[macro_use]
+extern crate enum_primitive;
 pub mod host;
 mod loader;
 pub mod types;
-pub use self::loader::EvmcLoaderErrorCode;
-use crate::loader::evmc_load_and_create;
+pub use crate::loader::{load_and_create, EvmcLoaderErrorCode};
 use crate::types::*;
 use evmc_sys as ffi;
 use std::ffi::CStr;
@@ -16,26 +17,6 @@ extern "C" {
     fn evmc_create() -> *mut ffi::evmc_vm;
 }
 
-fn error(err: EvmcLoaderErrorCode) -> Result<EvmcLoaderErrorCode, &'static str> {
-    match err {
-        EvmcLoaderErrorCode::EvmcLoaderSucces => Ok(EvmcLoaderErrorCode::EvmcLoaderSucces),
-        EvmcLoaderErrorCode::EvmcLoaderCannotOpen => Err("evmc loader: library cannot open"),
-        EvmcLoaderErrorCode::EvmcLoaderSymbolNotFound => {
-            Err("evmc loader: the EVMC create function not found")
-        }
-        EvmcLoaderErrorCode::EvmcLoaderInvalidArgument => {
-            panic!("evmc loader: filename argument is invalid")
-        }
-        EvmcLoaderErrorCode::EvmcLoaderInstanceCreationFailure => {
-            Err("evmc loader: VM instance creation failure")
-        }
-        EvmcLoaderErrorCode::EvmcLoaderAbiVersionMismatch => {
-            Err("evmc loader: ABI version mismatch")
-        }
-        _ => Err("evmc loader: unexpected error"),
-    }
-}
-
 pub struct EvmcVm {
     handle: *mut ffi::evmc_vm,
     host_interface: *mut ffi::evmc_host_interface,
@@ -141,13 +122,13 @@ impl EvmcVm {
 }
 
 pub fn load(fname: &str) -> (EvmcVm, Result<EvmcLoaderErrorCode, &'static str>) {
-    let (instance, ec) = evmc_load_and_create(fname);
+    let (instance, ec) = load_and_create(fname);
     (
         EvmcVm {
             handle: instance,
             host_interface: Box::into_raw(Box::new(host::get_evmc_host_interface())),
         },
-        error(ec),
+        ec,
     )
 }
 

bindings/rust/evmc-client/src/loader.rs

@@ -4,12 +4,22 @@
  */
 
 use evmc_sys as ffi;
-use libloading::{Library, Symbol};
-use std::ptr;
+use std::ffi::{CStr, CString};
+use std::os::raw::c_char;
 use std::str;
+extern crate num;
+use num::FromPrimitive;
+
+#[link(name = "evmc-loader")]
+extern "C" {
+    fn evmc_load_and_create(
+        filename: *const c_char,
+        evmc_loader_error_code: *mut i32,
+    ) -> *mut ffi::evmc_vm;
+    fn evmc_last_error_msg() -> *const c_char;
+}
 
-type EvmcCreate = extern "C" fn() -> *mut ffi::evmc_vm;
-
+enum_from_primitive! {
 #[derive(Debug)]
 pub enum EvmcLoaderErrorCode {
     /** The loader succeeded. */
@@ -36,39 +46,28 @@ pub enum EvmcLoaderErrorCode {
     /** The VM option value is invalid. */
     EvmcLoaderInvalidOptionValue = 7,
 }
+}
 
-pub fn evmc_load_and_create(fname: &str) -> (*mut ffi::evmc_vm, EvmcLoaderErrorCode) {
-    unsafe {
-        let mut instance: *mut ffi::evmc_vm = ptr::null_mut();
-
-        let library: Library = match Library::new(fname) {
-            Ok(lib) => lib,
-            Err(_) => {
-                return (instance, EvmcLoaderErrorCode::EvmcLoaderCannotOpen);
-            }
-        };
-
-        let evmc_create_fn: Symbol<EvmcCreate> = match library.get(b"evmc_create\0") {
-            Ok(symbol) => symbol,
-            Err(_) => {
-                return (instance, EvmcLoaderErrorCode::EvmcLoaderSymbolNotFound);
-            }
-        };
-
-        instance = evmc_create_fn();
-
-        if instance.is_null() {
-            return (
-                instance,
-                EvmcLoaderErrorCode::EvmcLoaderInstanceCreationFailure,
-            );
-        }
+fn error(err: EvmcLoaderErrorCode) -> Result<EvmcLoaderErrorCode, &'static str> {
+    match err {
+        EvmcLoaderErrorCode::EvmcLoaderSucces => Ok(EvmcLoaderErrorCode::EvmcLoaderSucces),
+        _ => unsafe { Err(CStr::from_ptr(evmc_last_error_msg()).to_str().unwrap()) },
+    }
+}
 
-        if (*instance).abi_version
-            != std::mem::transmute::<ffi::_bindgen_ty_1, i32>(ffi::EVMC_ABI_VERSION)
-        {
-            return (instance, EvmcLoaderErrorCode::EvmcLoaderAbiVersionMismatch);
-        }
-        return (instance, EvmcLoaderErrorCode::EvmcLoaderSucces);
+pub fn load_and_create(
+    fname: &str,
+) -> (
+    *mut ffi::evmc_vm,
+    Result<EvmcLoaderErrorCode, &'static str>,
+) {
+    let c_str = CString::new(fname).unwrap();
+    unsafe {
+        let mut error_code: i32 = 0;
+        let instance = evmc_load_and_create(c_str.as_ptr() as *const c_char, &mut error_code);
+        return (
+            instance,
+            error(EvmcLoaderErrorCode::from_i32(error_code).unwrap()),
+        );
     }
 }