wasm-instrument/rust-runner/src/main.rs

/*

    Rust contract demo runner

*/

extern crate parity_wasm;
extern crate wasm_utils;

mod call_args;
mod runtime;

use std::env;
use std::sync::Arc;
use parity_wasm::interpreter::{self, ModuleInstanceInterface};
use parity_wasm::elements;

pub const DEFAULT_MEMORY_INDEX: interpreter::ItemIndex = interpreter::ItemIndex::Internal(0);
pub type WasmMemoryPtr = i32;

fn main() {
    // First, load wasm contract as a module
    wasm_utils::init_log();

    let args = env::args().collect::<Vec<_>>();
    if args.len() != 2 {
        println!("Usage: {} contract.wasm", args[0]);
        return;
    }

    let module = parity_wasm::deserialize_file(&args[1]).expect("Module deserialization to succeed");

    let program = parity_wasm::interpreter::ProgramInstance::new()
        .expect("Program instance to be created");

    // Add module to the programm
    let module_instance = program.add_module("contract", module).expect("Module to be added successfully");

	{
	    let env_instance = program.module("env").expect("env module to exist");
        let env_memory = env_instance.memory(interpreter::ItemIndex::Internal(0))
            .expect("liner memory to exist");

        // Second, create runtime and program instance
        let mut runtime = runtime::Runtime::with_params(
            env_memory.clone(),  // memory shared ptr
            5*1024*1024,         // default stack space 
            65536,               // runner arbitrary gas limit
        );

        // Initialize call descriptor
        let descriptor = call_args::init(
            &*env_memory,
            &mut runtime, 
            &[3u8; 128],
        ).expect("call descriptor initialization to succeed");                

		// create native env module with native add && sub implementations
		let functions = interpreter::UserFunctions {
			executor: &mut runtime,
			functions: vec![
                interpreter::UserFunction {
                    name: "_storage_read".to_owned(),
                    params: vec![elements::ValueType::I32, elements::ValueType::I32],
                    result: Some(elements::ValueType::I32),
                },
                interpreter::UserFunction {
                    name: "_storage_write".to_owned(),
                    params: vec![elements::ValueType::I32, elements::ValueType::I32],
                    result: Some(elements::ValueType::I32),
                },
                interpreter::UserFunction {
                    name: "_malloc".to_owned(),
                    params: vec![elements::ValueType::I32],
                    result: Some(elements::ValueType::I32),
                },
                interpreter::UserFunction {
                    name: "gas".to_owned(),
                    params: vec![elements::ValueType::I32],
                    result: None,
                },
                interpreter::UserFunction {
                    name: "_free".to_owned(),
                    params: vec![elements::ValueType::I32],
                    result: None,
                },
			],
		};
		let native_env_instance = Arc::new(interpreter::env_native_module(env_instance, functions).unwrap());

        // Form ExecutionParams (payload + env link)
		let params = interpreter::ExecutionParams::with_external("env".into(), native_env_instance)
            .add_argument(interpreter::RuntimeValue::I32(descriptor));

        module_instance.execute_export("_call", params)
            .expect("_call to execute successfully")
            .expect("_call function to return result ptr");        
    }    
}