Wasm-wc: Core of initial Wasm component model language module support

This is the work of Alex Crichton.

This is written in Rust. The problem is that there is currently no
support on the C side of things for the component model, which is the
point of this module.

It talks to Unit via automatically generated bindings.

I've (Andrew) just made some minor tweaks to src/lib.rs, build.rs &
Cargo.toml to adjust some paths, adjust where we get the language module
config from and the module name and where it's located in the source
tree,

I also removed and disabled the tracking of the Cargo.lock file, this is
constantly changing and not tracking it seems right for 'libraries' and
dropped the README's...

Other than that I have tried to leave his work intact, subsequent
commits will make some larger changes, but I didn't want to intermix
them with Alex's work.

One such commit will update the module to use wasmtime 17 which brings
WASI 0.2.0 support.

Signed-off-by: Andrew Clayton <[email protected]>

Author: alexcrichton

src/wasm-wasi-component/.gitignore

@@ -0,0 +1,3 @@
+Cargo.lock
+
+target

src/wasm-wasi-component/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "wasm-wasi-component"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+anyhow = "1.0.75"
+bytes = "1.5.0"
+futures-util = { version = "0.3.29", default-features = false }
+http = "0.2.9"
+http-body = { version = "1.0.0-rc.2", default-features = false }
+http-body-util = "0.1.0-rc.2"
+tokio = { version = "1.33.0", default-features = false }
+wasmtime = "14.0.2"
+wasmtime-wasi = "14.0.2"
+wasmtime-wasi-http = "14.0.2"
+
+[build-dependencies]
+bindgen = "0.68.1"
+cc = "1.0.83"
+
+[profile.dev]
+panic = 'abort'
+
+[profile.release]
+panic = 'abort'

src/wasm-wasi-component/build.rs

@@ -0,0 +1,33 @@
+use std::env;
+use std::path::PathBuf;
+
+fn main() {
+    // Tell cargo to invalidate the built crate whenever the wrapper changes
+    println!("cargo:rerun-if-changed=wrapper.h");
+
+    let bindings = bindgen::Builder::default()
+        .clang_args(["-I", "../"])
+        .clang_args(["-I", "../../build/include"])
+        .header("./wrapper.h")
+        // only generate bindings for `nxt_*` header files
+        .allowlist_file(".*nxt_.*.h")
+        // generates an "improper_ctypes" warning and we don't need it anyway
+        .blocklist_function("nxt_vsprintf")
+        // Tell cargo to invalidate the built crate whenever any of the
+        // included header files changed.
+        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
+        // disable some features which aren't necessary
+        .layout_tests(false)
+        .derive_debug(false)
+        .generate()
+        .expect("Unable to generate bindings");
+
+    cc::Build::new()
+        .object("../../build/src/nxt_unit.o")
+        .compile("nxt-unit");
+
+    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
+    bindings
+        .write_to_file(out_path.join("bindings.rs"))
+        .expect("Couldn't write bindings!");
+}