Minimal optimization for cap-async-std.

Use `spawn_blocking` to run important blocking tests off the main
thread.

Author: sunfishcode

Cargo.toml

@@ -17,7 +17,8 @@ publish = false
 rustc_version = "0.3.0"
 
 [dev-dependencies]
-async-std = { version = "1.9.0", features = ["attributes"] }
+# Use a git dependency until https://github.com/async-rs/async-std/pull/937 is released.
+async-std = { git = "https://github.com/async-rs/async-std", features = ["attributes"] }
 anyhow = "1.0.37"
 cap-async-std = { path = "cap-async-std", version = "^0.13.11-alpha.0"}
 cap-fs-ext = { path = "cap-fs-ext", version = "^0.13.11-alpha.0"}
@@ -47,6 +48,10 @@ async_std_fs_utf8 = [
     "cap-fs-ext/async_std_fs_utf8"
 ]
 
+# Patch in a git dependency; see the dependency on async-std above.
+[patch.crates-io]
+async-std = { git = "https://github.com/async-rs/async-std", features = ["attributes", "unstable"] }
+
 [badges]
 maintenance = { status = "actively-developed" }
 

cap-async-std/Cargo.toml

@@ -14,13 +14,15 @@ edition = "2018"
 
 [dependencies]
 arf-strings = { version = "0.3.0", optional = true }
-async-std = { version = "1.9.0", features = ["attributes"] }
+# Enable "unstable" for `spawn_blocking`.
+# Use a git dependency until https://github.com/async-rs/async-std/pull/937 is released.
+async-std = { git = "https://github.com/async-rs/async-std", features = ["attributes", "unstable"] }
 cap-primitives = { path = "../cap-primitives", version = "^0.13.11-alpha.0"}
 ipnet = "2.3.0"
-unsafe-io = { version = "0.6.0", features = ["async-std"] }
+unsafe-io = { version = "0.6.9", features = ["async-std"] }
 
 [target.'cfg(not(windows))'.dependencies]
-posish = "0.6.0"
+posish = "0.6.1"
 
 [features]
 default = []

cap-async-std/README.md

@@ -15,9 +15,5 @@
 This crate provides a capability-based version of [`async-std`]. See the
 [toplevel README.md] for more information about capability-based security.
 
-At the moment, `cap-async-std` is a very rudimentary translation of [`cap-std`] to
-`async-std`. It hasn't yet been optimized to make effective use of `async`.
-
 [`async-std`]: https://crates.io/crates/async-std
-[`cap-std`]: https://github.com/bytecodealliance/cap-std/blob/main/cap-std/README.md
 [toplevel README.md]: https://github.com/bytecodealliance/cap-std/blob/main/README.md