rust: introduce evmc-loader wrapper

.bumpversion.cfg

@@ -57,6 +57,10 @@ replace = version = "{new_version}"
 search = version = "{current_version}"
 replace = version = "{new_version}"
 
+[bumpversion:file:bindings/rust/evmc-loader/Cargo.toml]
+search = version = "{current_version}"
+replace = version = "{new_version}"
+
 [bumpversion:file:examples/example-rust-vm/Cargo.toml]
 search = version = "{current_version}"
 replace = version = "{new_version}"

Cargo.toml

@@ -4,5 +4,6 @@ members = [
     "bindings/rust/evmc-vm",
     "bindings/rust/evmc-declare",
     "bindings/rust/evmc-declare-tests",
+    "bindings/rust/evmc-loader",
     "examples/example-rust-vm"
 ]

bindings/rust/evmc-loader/.gitignore

@@ -0,0 +1,3 @@
+/target
+**/*.rs.bk
+/Cargo.lock

bindings/rust/evmc-loader/Cargo.toml

@@ -0,0 +1,16 @@
+# EVMC: Ethereum Client-VM Connector API.
+# Copyright 2022 The EVMC Authors.
+# Licensed under the Apache License, Version 2.0.
+
+[package]
+name = "evmc-loader"
+version = "10.0.0-alpha.5"
+authors = ["Alex Beregszaszi <[email protected]>"]
+license = "Apache-2.0"
+repository = "https://github.com/ethereum/evmc"
+description = "Bindings to EVMC (Loader bindings)"
+edition = "2018"
+
+[build-dependencies]
+bindgen = "0.59"
+cmake = "0.1"

bindings/rust/evmc-loader/README.md

@@ -0,0 +1,5 @@
+# evmc-loader
+
+This is a Rust interface to [EVMC](https://github.com/ethereum/evmc).
+
+This crate contains a wrapper for the loader functionality.

bindings/rust/evmc-loader/build.rs

@@ -0,0 +1,40 @@
+// EVMC: Ethereum Client-VM Connector API.
+// Copyright 2022 The EVMC Authors.
+// Licensed under the Apache License, Version 2.0.
+
+extern crate bindgen;
+extern crate cmake;
+
+use cmake::Config;
+use std::env;
+use std::path::PathBuf;
+
+fn main() {
+    let dst = Config::new("../../../").build();
+
+    println!("cargo:rustc-link-lib=static=evmc-loader");
+    println!(
+        "cargo:rustc-link-search=native={}/build/lib/loader",
+        dst.display()
+    );
+
+    let bindings = bindgen::Builder::default()
+        .header("loader.h")
+        .generate_comments(false)
+        // do not generate an empty enum for EVMC_ABI_VERSION
+        .constified_enum("")
+        // generate Rust enums for each evmc enum
+        .rustified_enum("*")
+        .allowlist_type("evmc_.*")
+        .allowlist_function("evmc_.*")
+        .blocklist_type("evmc_vm")
+        // TODO: consider removing this
+        .size_t_is_usize(true)
+        .generate()
+        .expect("Unable to generate bindings");
+
+    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
+    bindings
+        .write_to_file(out_path.join("bindings.rs"))
+        .expect("Could not write bindings");
+}

bindings/rust/evmc-loader/loader.h

@@ -0,0 +1 @@
+../../../include/evmc/loader.h

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

@@ -0,0 +1,37 @@
+// EVMC: Ethereum Client-VM Connector API.
+// Copyright 2022 The EVMC Authors.
+// Licensed under the Apache License, Version 2.0.
+
+use std::ffi::{CStr, CString};
+
+mod sys;
+
+pub fn load_and_configure(
+    config: &str,
+) -> Result<*mut sys::evmc_vm, (sys::evmc_loader_error_code, String)> {
+    let config_cstr = CString::new(config).unwrap();
+    let mut error_code = sys::evmc_loader_error_code::EVMC_LOADER_UNSPECIFIED_ERROR;
+    let instance = unsafe { sys::evmc_load_and_configure(config_cstr.as_ptr(), &mut error_code) };
+
+    if error_code == sys::evmc_loader_error_code::EVMC_LOADER_SUCCESS {
+        assert!(!instance.is_null());
+        Ok(instance)
+    } else {
+        assert!(instance.is_null());
+        let error_msg = unsafe { CStr::from_ptr(sys::evmc_last_error_msg()) }
+            .to_str()
+            .expect("well formed error message") // TODO free the vm
+            .to_string();
+        Err((error_code, error_msg))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn load_fail() {
+        println!("{:?}", load_and_configure("test.so"));
+    }
+}

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

@@ -0,0 +1,31 @@
+// EVMC: Ethereum Client-VM Connector API.
+// Copyright 2022 The EVMC Authors.
+// Licensed under the Apache License, Version 2.0.
+
+#![allow(non_upper_case_globals)]
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+
+include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
+
+// Defining evmc_vm here, because bindgen cannot create a useful declaration yet.
+
+pub type evmc_vm = ::std::os::raw::c_void;
+
+#[cfg(test)]
+mod tests {
+    use std::ffi::CString;
+    use std::os::raw::c_char;
+
+    use super::*;
+
+    #[test]
+    fn load_fail() {
+        let c_str = CString::new("test.so").unwrap();
+        unsafe {
+            let mut error_code = evmc_loader_error_code::EVMC_LOADER_UNSPECIFIED_ERROR;
+            let instance = evmc_load_and_create(c_str.as_ptr() as *const c_char, &mut error_code);
+            println!("{:?} {:?}", error_code, instance);
+        }
+    }
+}