Add an example

Author: coolreader18

Cargo.toml

@@ -17,3 +17,8 @@ wasmer-wasi = "0.17.0"
 typetag = "0.1.5"
 
 serde = "1.0.114"
+
+
+[[example]]
+name = "wasirun"
+required-features = ["tokio/io-std", "tokio/macros"]

examples/wasirun.rs

@@ -0,0 +1,32 @@
+use tokio::prelude::*;
+use wasi_process::WasiProcess;
+use wasmer_wasi::{state::WasiState, WasiVersion};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut args = std::env::args().skip(1);
+    let wasm = std::fs::read(args.next().expect("must pass wasm file"))?;
+    let module = wasmer_runtime::compile(&wasm)?;
+    let mut state = WasiState::new("progg");
+    wasi_process::add_stdio(&mut state);
+    state.args(args).preopen_dir(".")?;
+    let imports = wasmer_wasi::generate_import_object_from_state(
+        state.build()?,
+        wasmer_wasi::get_wasi_version(&module, false).unwrap_or(WasiVersion::Latest),
+    );
+    let mut wasi = WasiProcess::new(module.instantiate(&imports)?);
+    let mut proc_stdin = wasi.stdin.take().unwrap();
+    let mut stdin = io::stdin();
+    let mut proc_stdout = wasi.stdout.take().unwrap();
+    let mut stdout = io::stdout();
+    let mut proc_stderr = wasi.stderr.take().unwrap();
+    let mut stderr = io::stderr();
+    let proc_fut = wasi.spawn();
+    tokio::try_join!(
+        io::copy(&mut stdin, &mut proc_stdin),
+        io::copy(&mut proc_stdout, &mut stdout),
+        io::copy(&mut proc_stderr, &mut stderr),
+    )?;
+    proc_fut.await?;
+    Ok(())
+}

src/lib.rs

@@ -247,3 +247,5 @@ impl fmt::Display for SpawnError {
         }
     }
 }
+
+impl std::error::Error for SpawnError {}