wasm-pack utility to pack wasm files into transactions payload

pack/src/main.rs

@@ -0,0 +1,32 @@
+extern crate parity_wasm;
+extern crate wasm_utils;
+extern crate clap;
+
+use clap::{App, Arg};
+
+fn main() {
+    wasm_utils::init_log();
+
+    let matches = App::new("wasm-opt")
+                        .arg(Arg::with_name("input")
+                            .index(1)
+                            .required(true)
+                            .help("Input WASM file"))
+                        .arg(Arg::with_name("output")
+                            .index(2)
+                            .required(true)
+                            .help("Output WASM file"))
+                        .get_matches();
+
+    let input = matches.value_of("input").expect("is required; qed");
+    let output = matches.value_of("output").expect("is required; qed");
+
+    // doing serialization roundtrip to make sure the input is a valid wasm module
+    let module = parity_wasm::deserialize_file(&input).expect("Failed to load wasm module from file");
+    let bytes = parity_wasm::serialize(module).expect("Failed to serialize wasm module");
+
+    // Wrap contract code into the wasm module that returns it
+    let packed_module = wasm_utils::pack_instance(bytes);
+
+    parity_wasm::serialize_to_file(&output, packed_module).unwrap();
+}