feat: add binding crate integrations (#89)

* feat(io): implement `Read` and `Write` for streams

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

* feat(rand): add `rand` crate integration

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

* chore: split examples into `std` and `no_std`

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

* ci: build all std and no_std examples

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

* refactor(rand): use `writeln` to write to stdout

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

* feat(wasi-ext): add workspace crate

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

* ci: build in `--workspace` mode

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

---------

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

.github/workflows/main.yml

@@ -13,11 +13,11 @@ jobs:
     - name: Install Rust
       run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }} && rustup component add rustfmt
     - run: rustup target add wasm32-wasi wasm32-unknown-unknown
-    - 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 test --doc
+    - run: cargo build --workspace
+    - run: cargo build --workspace --no-default-features
+    - run: cargo build --workspace --target wasm32-wasi
+    - run: cargo build --workspace --target wasm32-wasi --no-default-features
+    - run: cargo test --workspace --doc
     - name: Install Wasmtime
       uses: bytecodealliance/actions/wasmtime/setup@v1
       with:
@@ -26,16 +26,38 @@ jobs:
       uses: bytecodealliance/actions/wasm-tools/setup@v1
       with:
         version: "1.202.0"
-    - run: cargo build --examples --target wasm32-wasi
     - run: curl -LO https://github.com/bytecodealliance/wasmtime/releases/download/v19.0.0/wasi_snapshot_preview1.command.wasm
+
+    - run: cargo build --examples --target wasm32-wasi --no-default-features
+
+    - run: wasm-tools component new ./target/wasm32-wasi/debug/examples/hello-world-no_std.wasm --adapt ./wasi_snapshot_preview1.command.wasm -o component.wasm
+    - run: wasmtime run component.wasm
+
+    - run: cargo build --examples --target wasm32-unknown-unknown --no-default-features
+
+    - run: wasm-tools component new ./target/wasm32-unknown-unknown/debug/examples/cli_command_no_std.wasm -o component.wasm
+    - run: wasmtime run component.wasm
+
+    - run: wasm-tools component new ./target/wasm32-unknown-unknown/debug/examples/http_proxy_no_std.wasm -o component.wasm
+    - run: wasm-tools component targets wit component.wasm -w wasi:http/proxy
+
+    - run: cargo build --examples --target wasm32-wasi
+
     - 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
+
     - run: cargo build --examples --target wasm32-unknown-unknown
+
     - run: wasm-tools component new ./target/wasm32-unknown-unknown/debug/examples/cli_command.wasm -o component.wasm
     - run: wasmtime run component.wasm
+
     - run: wasm-tools component new ./target/wasm32-unknown-unknown/debug/examples/http_proxy.wasm -o component.wasm
     - run: wasm-tools component targets wit component.wasm -w wasi:http/proxy
 
+    - run: cargo build --examples --workspace --target wasm32-wasi --features rand
+
+    - run: wasm-tools component new ./target/wasm32-wasi/debug/examples/rand.wasm --adapt ./wasi_snapshot_preview1.command.wasm -o component.wasm
+    - run: wasmtime run component.wasm
 
   rustfmt:
     name: Rustfmt

Cargo.toml

@@ -2,14 +2,26 @@
 name = "wasi"
 version = "0.13.0+wasi-0.2.0"
 authors = ["The Cranelift Project Developers"]
-license = "Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT"
 description = "WASI API bindings for Rust"
-edition = "2021"
 categories = ["no-std", "wasm"]
 keywords = ["webassembly", "wasm"]
-repository = "https://github.com/bytecodealliance/wasi-rs"
 readme = "README.md"
 documentation = "https://docs.rs/wasi"
+license.workspace = true
+edition.workspace = true
+repository.workspace = true
+
+[workspace.package]
+edition = "2021"
+license = "Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT"
+repository = "https://github.com/bytecodealliance/wasi-rs"
+
+[workspace.dependencies]
+rand = { version = "0.8.5", default-features = false }
+wasi = { version = "0.13", path = ".", default-features = false }
+
+[workspace]
+members = ["./crates/*"]
 
 [dependencies]
 wit-bindgen-rt = { version = "0.23.0", features = ["bitflags"] }
@@ -25,10 +37,24 @@ std = []
 # Unstable feature to support being a libstd dependency
 rustc-dep-of-std = ["compiler_builtins", "core", "rustc-std-workspace-alloc"]
 
+[[example]]
+name = "cli-command-no_std"
+crate-type = ["cdylib"]
+
 [[example]]
 name = "cli-command"
 crate-type = ["cdylib"]
+required-features = ["std"]
+
+[[example]]
+name = "hello-world"
+required-features = ["std"]
+
+[[example]]
+name = "http-proxy-no_std"
+crate-type = ["cdylib"]
 
 [[example]]
 name = "http-proxy"
 crate-type = ["cdylib"]
+required-features = ["std"]

crates/wasi-ext/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "wasi-ext"
+version = "0.1.0"
+authors = ["Roman Volosatovs <rvolosatovs@riseup.net>"]
+description = "Third-party crate integrations for WASI"
+
+license.workspace = true
+edition.workspace = true
+repository.workspace = true
+
+[features]
+default = ["std"]
+std = ["wasi/std"]
+
+[dependencies]
+rand = { workspace = true, optional = true }
+wasi = { workspace = true }
+
+[[example]]
+name = "rand"
+required-features = ["rand", "std"]

crates/wasi-ext/examples/rand.rs

@@ -0,0 +1,16 @@
+use std::io::Write as _;
+
+use wasi_ext::rand::rand::Rng as _;
+use wasi_ext::rand::{HostInsecureRng, HostRng};
+
+fn main() {
+    let mut stdout = wasi::cli::stdout::get_stdout();
+
+    let r: u64 = HostRng.gen();
+    writeln!(stdout, "Cryptographically-secure random u64 is {r}").unwrap();
+
+    let r: u64 = HostInsecureRng.gen();
+    writeln!(stdout, "Pseudo-random u64 is {r}").unwrap();
+
+    stdout.flush().unwrap();
+}

crates/wasi-ext/src/lib.rs

@@ -0,0 +1,2 @@
+#[cfg(feature = "rand")]
+pub mod rand;

crates/wasi-ext/src/rand.rs

@@ -0,0 +1,69 @@
+pub use rand;
+
+use rand::{CryptoRng, RngCore};
+
+/// The secure interface for cryptographically-secure random numbers
+pub struct HostRng;
+
+impl CryptoRng for HostRng {}
+
+impl RngCore for HostRng {
+    #[inline]
+    fn next_u32(&mut self) -> u32 {
+        wasi::random::random::get_random_u64() as _
+    }
+
+    #[inline]
+    fn next_u64(&mut self) -> u64 {
+        wasi::random::random::get_random_u64()
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        let n = dest.len();
+        if usize::BITS <= u64::BITS || n <= u64::MAX as _ {
+            dest.copy_from_slice(&wasi::random::random::get_random_bytes(n as _));
+        } else {
+            let (head, tail) = dest.split_at_mut(u64::MAX as _);
+            head.copy_from_slice(&wasi::random::random::get_random_bytes(u64::MAX));
+            self.fill_bytes(tail);
+        }
+    }
+
+    #[inline]
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand::Error> {
+        self.fill_bytes(dest);
+        Ok(())
+    }
+}
+
+/// The insecure interface for insecure pseudo-random numbers
+pub struct HostInsecureRng;
+
+impl RngCore for HostInsecureRng {
+    #[inline]
+    fn next_u32(&mut self) -> u32 {
+        wasi::random::insecure::get_insecure_random_u64() as _
+    }
+
+    #[inline]
+    fn next_u64(&mut self) -> u64 {
+        wasi::random::insecure::get_insecure_random_u64()
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        let n = dest.len();
+        if usize::BITS <= u64::BITS || n <= u64::MAX as _ {
+            dest.copy_from_slice(&wasi::random::insecure::get_insecure_random_bytes(n as _));
+        } else {
+            let (head, tail) = dest.split_at_mut(u64::MAX as _);
+            head.copy_from_slice(&wasi::random::insecure::get_insecure_random_bytes(u64::MAX));
+            self.fill_bytes(tail);
+        }
+    }
+
+    #[inline]
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand::Error> {
+        self.fill_bytes(dest);
+        Ok(())
+    }
+}

examples/cli-command-no_std.rs

@@ -0,0 +1,11 @@
+wasi::cli::command::export!(Example);
+
+struct Example;
+
+impl wasi::exports::cli::run::Guest for Example {
+    fn run() -> Result<(), ()> {
+        let stdout = wasi::cli::stdout::get_stdout();
+        stdout.blocking_write_and_flush(b"Hello, WASI!").unwrap();
+        Ok(())
+    }
+}

examples/cli-command.rs

@@ -1,11 +1,14 @@
+use std::io::Write as _;
+
 wasi::cli::command::export!(Example);
 
 struct Example;
 
 impl wasi::exports::cli::run::Guest for Example {
     fn run() -> Result<(), ()> {
-        let stdout = wasi::cli::stdout::get_stdout();
-        stdout.blocking_write_and_flush(b"Hello, WASI!").unwrap();
+        let mut stdout = wasi::cli::stdout::get_stdout();
+        stdout.write_all(b"Hello, WASI!").unwrap();
+        stdout.flush().unwrap();
         Ok(())
     }
 }

examples/hello-world-no_std.rs

@@ -0,0 +1,4 @@
+fn main() {
+    let stdout = wasi::cli::stdout::get_stdout();
+    stdout.blocking_write_and_flush(b"Hello, world!\n").unwrap();
+}

examples/hello-world.rs

@@ -1,4 +1,7 @@
+use std::io::Write as _;
+
 fn main() {
-    let stdout = wasi::cli::stdout::get_stdout();
-    stdout.blocking_write_and_flush(b"Hello, world!\n").unwrap();
+    let mut stdout = wasi::cli::stdout::get_stdout();
+    stdout.write_all(b"Hello, world!\n").unwrap();
+    stdout.flush().unwrap();
 }

examples/http-proxy-no_std.rs

@@ -0,0 +1,22 @@
+use wasi::http::types::{
+    Fields, IncomingRequest, OutgoingBody, OutgoingResponse, ResponseOutparam,
+};
+
+wasi::http::proxy::export!(Example);
+
+struct Example;
+
+impl wasi::exports::http::incoming_handler::Guest for Example {
+    fn handle(_request: IncomingRequest, response_out: ResponseOutparam) {
+        let resp = OutgoingResponse::new(Fields::new());
+        let body = resp.body().unwrap();
+
+        ResponseOutparam::set(response_out, Ok(resp));
+
+        let out = body.write().unwrap();
+        out.blocking_write_and_flush(b"Hello, WASI!").unwrap();
+        drop(out);
+
+        OutgoingBody::finish(body, None).unwrap();
+    }
+}

examples/http-proxy.rs

@@ -1,3 +1,5 @@
+use std::io::Write as _;
+
 use wasi::http::types::{
     Fields, IncomingRequest, OutgoingBody, OutgoingResponse, ResponseOutparam,
 };
@@ -13,8 +15,9 @@ impl wasi::exports::http::incoming_handler::Guest for Example {
 
         ResponseOutparam::set(response_out, Ok(resp));
 
-        let out = body.write().unwrap();
-        out.blocking_write_and_flush(b"Hello, WASI!").unwrap();
+        let mut out = body.write().unwrap();
+        out.write_all(b"Hello, WASI!").unwrap();
+        out.flush().unwrap();
         drop(out);
 
         OutgoingBody::finish(body, None).unwrap();

src/errors.rs → src/ext/mod.rs

@@ -1,8 +1,8 @@
+#[cfg(feature = "std")]
+mod std;
+
 impl core::fmt::Display for crate::io::error::Error {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         f.write_str(&self.to_debug_string())
     }
 }
-
-#[cfg(feature = "std")]
-impl std::error::Error for crate::io::error::Error {}

src/ext/std.rs

@@ -0,0 +1,69 @@
+use std::error::Error;
+use std::io;
+use std::num::NonZeroU64;
+
+use crate::io::streams::StreamError;
+
+impl Error for crate::io::error::Error {}
+
+impl io::Read for crate::io::streams::InputStream {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = buf
+            .len()
+            .try_into()
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+        match self.blocking_read(n) {
+            Ok(chunk) => {
+                let n = chunk.len();
+                if n > buf.len() {
+                    return Err(io::Error::new(
+                        io::ErrorKind::Other,
+                        "more bytes read than requested",
+                    ));
+                }
+                buf[..n].copy_from_slice(&chunk);
+                Ok(n)
+            }
+            Err(StreamError::Closed) => Ok(0),
+            Err(StreamError::LastOperationFailed(e)) => {
+                Err(io::Error::new(io::ErrorKind::Other, e.to_debug_string()))
+            }
+        }
+    }
+}
+
+impl io::Write for crate::io::streams::OutputStream {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let n = loop {
+            match self.check_write().map(NonZeroU64::new) {
+                Ok(Some(n)) => {
+                    break n;
+                }
+                Ok(None) => {
+                    self.subscribe().block();
+                }
+                Err(StreamError::Closed) => return Ok(0),
+                Err(StreamError::LastOperationFailed(e)) => {
+                    return Err(io::Error::new(io::ErrorKind::Other, e.to_debug_string()))
+                }
+            };
+        };
+        let n = n
+            .get()
+            .try_into()
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+        let n = buf.len().min(n);
+        crate::io::streams::OutputStream::write(self, &buf[..n]).map_err(|e| match e {
+            StreamError::Closed => io::ErrorKind::UnexpectedEof.into(),
+            StreamError::LastOperationFailed(e) => {
+                io::Error::new(io::ErrorKind::Other, e.to_debug_string())
+            }
+        })?;
+        Ok(n)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.blocking_flush()
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))
+    }
+}

src/lib.rs

@@ -179,7 +179,7 @@
 #[cfg(feature = "std")]
 extern crate std;
 
-mod errors;
+pub mod ext;
 
 // These modules are all auto-generated by `./ci/regenerate.sh`
 mod bindings;