Update WASI bindings to 0.2.0 and the component model (#72)

* Remove old wasi-ephemeral/witx-bindgen crates

* Copy WIT files from Wasmtime

* Update to WASI 0.2.0 bindings

* Update some manifest fields

* Add a small example

* CI tweaks

* Install wit-bindgen on CI

* Specify versions of wasmtime/wasm-tools on CI

* Fix wit-bindgen-cli install

* Flag wit/deps as generated as well

* Fix yml syntax

* Fix wasmtime tag

* Update README

Author: alexcrichton

.gitattributes

@@ -0,0 +1,5 @@
+# This is generated by `wit-bindgen`
+src/bindings.rs linguist-generated=true
+
+# This is copied from other repos so diffs aren't super interesting by default
+wit/deps linguist-generated=true

.github/workflows/main.yml

@@ -9,36 +9,44 @@ jobs:
       matrix:
         rust: [stable, beta, nightly]
     steps:
-    - uses: actions/checkout@v1
-      with:
-        submodules: true
+    - uses: actions/checkout@v4
     - name: Install Rust
       run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }} && rustup component add rustfmt
     - run: rustup target add wasm32-wasi
     - run: cargo build
     - run: cargo build --no-default-features
     - run: cargo build --target wasm32-wasi
     - run: cargo build --target wasm32-wasi --no-default-features
-    - run: cargo build -p wasi-ephemeral
+    - name: Install Wasmtime
+      uses: bytecodealliance/actions/wasmtime/setup@v1
+      with:
+        version: "v17.0.0"
+    - name: Install wasm-tools
+      uses: bytecodealliance/actions/wasm-tools/setup@v1
+      with:
+        version: "1.0.57"
+    - run: cargo build --examples --target wasm32-wasi
+    - run: curl -LO https://github.com/bytecodealliance/wasmtime/releases/download/v17.0.0/wasi_snapshot_preview1.command.wasm
+    - run: wasm-tools component new ./target/wasm32-wasi/debug/examples/hello-world.wasm --adapt ./wasi_snapshot_preview1.command.wasm -o component.wasm
+    - run: wasmtime run component.wasm
+
 
   rustfmt:
     name: Rustfmt
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
-      with:
-        submodules: true
+    - uses: actions/checkout@v4
     - name: Install Rust
       run: rustup update stable && rustup default stable && rustup component add rustfmt
     - run: cargo fmt -- --check
 
   generate:
-    name: Test Generated Code
+    name: Ensure generated code up-to-date
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
-      with:
-        submodules: true
+    - uses: actions/checkout@v4
     - name: Install Rust
       run: rustup update stable && rustup default stable
-    - run: cargo test -p witx-bindgen
+    - run: cargo install wit-bindgen-cli@0.16.0
+    - run: ./ci/regenerate.sh
+    - run: git diff --exit-code

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "crates/witx-bindgen/WASI"]
-	path = crates/witx-bindgen/WASI
-	url = https://github.com/WebAssembly/WASI

Cargo.toml

@@ -1,20 +1,19 @@
 [package]
 name = "wasi"
-version = "0.11.0+wasi-snapshot-preview1"
+version = "0.12.0+wasi-0.2.0"
 authors = ["The Cranelift Project Developers"]
 license = "Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT"
-description = "Experimental WASI API bindings for Rust"
-edition = "2018"
+description = "WASI API bindings for Rust"
+edition = "2021"
 categories = ["no-std", "wasm"]
 keywords = ["webassembly", "wasm"]
 repository = "https://github.com/bytecodealliance/wasi"
 readme = "README.md"
 documentation = "https://docs.rs/wasi"
 
-[workspace]
-members = ['crates/witx-bindgen', 'crates/wasi-ephemeral']
-
 [dependencies]
+wit-bindgen = { version = "0.16", default-features = false, features = ['realloc'] }
+
 # When built as part of libstd
 compiler_builtins = { version = "0.1", optional = true }
 core = { version = "1.0", optional = true, package = "rustc-std-workspace-core" }

README.md

@@ -14,74 +14,88 @@
   </p>
 </div>
 
-This crate contains API bindings for [WASI](https://github.com/WebAssembly/WASI)
-system calls in Rust, and currently reflects the `wasi_snapshot_preview1`
-module. This crate is quite low-level and provides conceptually a "system call"
-interface. In most settings, it's better to use the Rust standard library, which
-has WASI support.
+This crate contains bindings for [WASI](https://github.com/WebAssembly/WASI)
+APIs for the worlds:
 
-The `wasi` crate is also entirely procedurally generated from the `*.witx` files
-describing the WASI apis. While some conveniences are provided the bindings here
-are intentionally low-level!
+* [`wasi:cli/command`]
+* [`wasi:http/proxy`]
+
+This crate is procedurally generated from [WIT] files using [`wit-bindgen`].
+
+[`wasi:cli/command`]: https://github.com/WebAssembly/wasi-cli
+[`wasi:http/proxy`]: https://github.com/WebAssembly/wasi-http
+[WIT]: https://component-model.bytecodealliance.org/design/wit.html
+[`wit-bindgen`]: https://github.com/bytecodealliance/wit-bindgen
+[components]: https://component-model.bytecodealliance.org/
+[`wasm-tools`]: https://github.com/bytecodealliance/wasm-tools
 
 # Usage
 
 First you can depend on this crate via `Cargo.toml`:
 
 ```toml
 [dependencies]
-wasi = "0.8.0"
+wasi = "0.12.0"
 ```
 
 Next you can use the APIs in the root of the module like so:
 
 ```rust
 fn main() {
-    let stdout = 1;
-    let message = "Hello, World!\n";
-    let data = [wasi::Ciovec {
-        buf: message.as_ptr(),
-        buf_len: message.len(),
-    }];
-    wasi::fd_write(stdout, &data).unwrap();
+    let stdout = wasi::cli::stdout::get_stdout();
+    stdout.blocking_write_and_flush(b"Hello, world!\n").unwrap();
 }
 ```
 
-Next you can use a tool like [`cargo
-wasi`](https://github.com/bytecodealliance/cargo-wasi) to compile and run your
-project:
+This crate is intended to target [components] but today you need to go through
+the intermediate build step of a core WebAssembly module using the `wasm32-wasi`
+target:
 
-To compile Rust projects to wasm using WASI, use the `wasm32-wasi` target,
-like this:
+```
+$ cargo build --target wasm32-wasi
+```
+
+Next you'll want an "adapter" to convert the Rust standard library's usage of
+`wasi_snapshot_preview1` to the component model. An example adapter can be found
+from [Wasmtime's release page](https://github.com/bytecodealliance/wasmtime/releases/download/v17.0.0/wasi_snapshot_preview1.command.wasm).
 
 ```
-$ cargo wasi run
-   Compiling wasi v0.8.0+wasi-snapshot-preview1
-   Compiling wut v0.1.0 (/code)
-    Finished dev [unoptimized + debuginfo] target(s) in 0.34s
-     Running `/.cargo/bin/cargo-wasi target/wasm32-wasi/debug/wut.wasm`
-     Running `target/wasm32-wasi/debug/wut.wasm`
-Hello, World!
+$ curl -LO https://github.com/bytecodealliance/wasmtime/releases/download/v17.0.0/wasi_snapshot_preview1.command.wasm
 ```
 
-# Development
+Next to create a component you'll use the [`wasm-tools`] CLI to create a
+component:
 
-The bulk of the `wasi` crate is generated by the `witx-bindgen` tool, which lives at
-`crates/witx-bindgen` and is part of the cargo workspace.
+```
+$ cargo install wasm-tools
+$ wasm-tools component new target/wasm32-wasi/debug/foo.wasm \
+    --adapt ./wasi_snapshot_preview1.command.wasm \
+    -o component.wasm
+```
 
-The `src/lib_generated.rs` file can be re-generated with the following
-command:
+And finally the component can be run by a runtime that has Component Model
+support, such as [Wasmtime]:
 
 ```
-cargo run -p witx-bindgen -- crates/witx-bindgen/WASI/phases/snapshot/witx/wasi_snapshot_preview1.witx > src/lib_generated.rs
+$ wasmtime run component.wasm
+Hello, world!
 ```
 
-Note that this uses the WASI standard repository as a submodule. If you do not
-have this submodule present in your source tree, run:
+[Wasmtime]: https://github.com/bytecodealliance/wasmtime
+
+# Development
+
+The bulk of the `wasi` crate is generated by the [`wit-bindgen`] tool. The
+`src/bindings.rs` file can be regenerated with:
+
 ```
-git submodule update --init
+$ ./ci/regenerate.sh
 ```
 
+WASI definitions are located in the `wit` directory of this repository.
+Currently they're copied from upstream repositories but are hoped to be better
+managed in the future.
+
 # License
 
 This project is licensed under the Apache 2.0 license with the LLVM exception.

ci/regenerate.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+set -ex
+
+wit-bindgen rust wit --out-dir src --std-feature
+
+# rustfmt chokes on the raw output of wit-bindgen right now due to trailling
+# whitespace (unsure as to why), so format it with some options first to get it
+# into a better state before applying the final format with default options
+# which gets this to succeed.
+#
+# NB: this should be considered a bug in wit-bindgen that this is required to do
+# twice. Passing `--rustfmt` to `wit-bindgen` should work.
+rustfmt src/bindings.rs --edition 2021 --config-path ./ci/rustfmt-bindings.toml
+rustfmt src/bindings.rs --edition 2021

ci/rustfmt-bindings.toml

@@ -0,0 +1,2 @@
+max_width = 100
+tab_spaces = 2