use tokio's File with a cap-std Dir

Cargo.lock

@@ -3138,7 +3138,14 @@ dependencies = [
 name = "wasi-tokio"
 version = "0.26.0"
 dependencies = [
+ "cap-fs-ext",
+ "cap-std",
+ "cap-time-ext",
+ "fs-set-times",
+ "system-interface",
+ "tempfile",
  "tokio",
+ "unsafe-io",
  "wasi-cap-std-sync",
  "wasi-common",
  "wiggle",

crates/wasi-common/tokio/Cargo.toml

@@ -15,4 +15,14 @@ include = ["src/**/*", "LICENSE" ]
 wasi-common = { path = "../", version = "0.26.0" }
 wasi-cap-std-sync = { path = "../cap-std-sync", version = "0.26.0" }
 wiggle = { path = "../../wiggle", version = "0.26.0" }
-tokio = { version = "1.5.0", features = [ "rt", "time" ] }
+tokio = { version = "1.5.0", features = [ "rt", "fs", "time" ] }
+cap-std = "0.13.7"
+cap-fs-ext = "0.13.7"
+cap-time-ext = "0.13.7"
+fs-set-times = "0.3.1"
+unsafe-io = "0.6.2"
+system-interface = { version = "0.6.3", features = ["cap_std_impls"] }
+
+[dev-dependencies]
+tempfile = "3.1.0"
+tokio = { features = [ "macros" ] }

crates/wasi-common/tokio/src/lib.rs

@@ -1,14 +1,14 @@
+mod dir;
+mod file;
+
 use std::cell::RefCell;
 use std::path::Path;
 use std::rc::Rc;
 pub use wasi_cap_std_sync::{clocks_ctx, random_ctx, Dir};
-use wasi_common::{Table, WasiCtx};
+use wasi_common::{Error, Table, WasiCtx};
 
 pub fn sched_ctx() -> Box<dyn wasi_common::WasiSched> {
-    use wasi_common::{
-        sched::{Duration, Poll, WasiSched},
-        Error,
-    };
+    use wasi_common::sched::{Duration, Poll, WasiSched};
     struct AsyncSched;
 
     #[wiggle::async_trait]