Add WASI p2 support (#488)

* Add WASI p2 support

* Use store optional to determine WASI context version

* Centralize error messages about WASI

* Use static functions for adding WASI to linker

* Fix examples and error text

* Fix docs

* Fix inaccurate comment

* Remove unused interned values

Author: jeffcharles

examples/linking.rb

@@ -2,9 +2,10 @@
 
 engine = Wasmtime::Engine.new
 
-# Create a linker to link modules together. We want to use WASI with
-# the linker, so we pass in `wasi: true`.
-linker = Wasmtime::Linker.new(engine, wasi: true)
+# Create a linker to link modules together.
+linker = Wasmtime::Linker.new(engine)
+# We want to use WASI with # the linker, so we call add_to_linker_sync.
+Wasmtime::WASI::P1.add_to_linker_sync(linker)
 
 mod1 = Wasmtime::Module.from_file(engine, "examples/linking1.wat")
 mod2 = Wasmtime::Module.from_file(engine, "examples/linking2.wat")
@@ -13,7 +14,7 @@
   .inherit_stdin
   .inherit_stdout
 
-store = Wasmtime::Store.new(engine, wasi_config: wasi_config)
+store = Wasmtime::Store.new(engine, wasi_p1_config: wasi_config)
 
 # Instantiate `mod2` which only uses WASI, then register
 # that instance with the linker so `mod1` can use it.

examples/wasi-p2.rb

@@ -0,0 +1,17 @@
+require "wasmtime"
+
+engine = Wasmtime::Engine.new
+component = Wasmtime::Component::Component.from_file(engine, "spec/fixtures/wasi-debug-p2.wasm")
+
+linker = Wasmtime::Component::Linker.new(engine)
+Wasmtime::WASI::P2.add_to_linker_sync(linker)
+
+wasi_config = Wasmtime::WasiConfig.new
+  .set_stdin_string("hi!")
+  .inherit_stdout
+  .inherit_stderr
+  .set_argv(ARGV)
+  .set_env(ENV)
+store = Wasmtime::Store.new(engine, wasi_config: wasi_config)
+
+Wasmtime::Component::WasiCommand.new(store, component, linker).call_run(store)

examples/wasi.rb

@@ -3,15 +3,16 @@
 engine = Wasmtime::Engine.new
 mod = Wasmtime::Module.from_file(engine, "spec/fixtures/wasi-debug.wasm")
 
-linker = Wasmtime::Linker.new(engine, wasi: true)
+linker = Wasmtime::Linker.new(engine)
+Wasmtime::WASI::P1.add_to_linker_sync(linker)
 
 wasi_config = Wasmtime::WasiConfig.new
   .set_stdin_string("hi!")
   .inherit_stdout
   .inherit_stderr
   .set_argv(ARGV)
   .set_env(ENV)
-store = Wasmtime::Store.new(engine, wasi_config: wasi_config)
+store = Wasmtime::Store.new(engine, wasi_p1_config: wasi_config)
 
 instance = linker.instantiate(store, mod)
 instance.invoke("_start")

ext/src/ruby_api/component.rs

@@ -2,6 +2,7 @@ mod convert;
 mod func;
 mod instance;
 mod linker;
+mod wasi_command;
 
 use super::root;
 use magnus::{
@@ -13,6 +14,8 @@ use wasmtime::component::Component as ComponentImpl;
 
 pub use func::Func;
 pub use instance::Instance;
+pub use linker::Linker;
+pub use wasi_command::WasiCommand;
 
 pub fn component_namespace(ruby: &Ruby) -> RModule {
     static COMPONENT_NAMESPACE: Lazy<RModule> =
@@ -162,6 +165,7 @@ pub fn init(ruby: &Ruby) -> Result<(), Error> {
     instance::init(ruby, &namespace)?;
     func::init(ruby, &namespace)?;
     convert::init(ruby)?;
+    wasi_command::init(ruby, &namespace)?;
 
     Ok(())
 }

ext/src/ruby_api/component/linker.rs

@@ -2,18 +2,26 @@ use super::{Component, Instance};
 use crate::{
     err,
     ruby_api::{
+        errors,
         store::{StoreContextValue, StoreData},
         Engine, Module, Store,
     },
 };
-use std::{borrow::BorrowMut, cell::RefCell};
+use std::{
+    borrow::BorrowMut,
+    cell::{RefCell, RefMut},
+};
 
 use crate::error;
 use magnus::{
     class, function, gc::Marker, method, r_string::RString, scan_args, typed_data::Obj,
     DataTypeFunctions, Error, Module as _, Object, RModule, Ruby, TryConvert, TypedData, Value,
 };
 use wasmtime::component::{Linker as LinkerImpl, LinkerInstance as LinkerInstanceImpl};
+use wasmtime_wasi::{
+    p2::{IoView, WasiCtx, WasiView},
+    ResourceTable,
+};
 
 /// @yard
 /// @rename Wasmtime::Component::Linker
@@ -23,6 +31,7 @@ use wasmtime::component::{Linker as LinkerImpl, LinkerInstance as LinkerInstance
 pub struct Linker {
     inner: RefCell<LinkerImpl<StoreData>>,
     refs: RefCell<Vec<Value>>,
+    has_wasi: RefCell<bool>,
 }
 unsafe impl Send for Linker {}
 
@@ -38,13 +47,23 @@ impl Linker {
     /// @param engine [Engine]
     /// @return [Linker]
     pub fn new(engine: &Engine) -> Result<Self, Error> {
-        let linker = LinkerImpl::new(engine.get());
+        let linker: LinkerImpl<StoreData> = LinkerImpl::new(engine.get());
+
         Ok(Linker {
             inner: RefCell::new(linker),
             refs: RefCell::new(Vec::new()),
+            has_wasi: RefCell::new(false),
         })
     }
 
+    pub(crate) fn inner_mut(&self) -> RefMut<'_, LinkerImpl<StoreData>> {
+        self.inner.borrow_mut()
+    }
+
+    pub(crate) fn has_wasi(&self) -> bool {
+        *self.has_wasi.borrow()
+    }
+
     /// @yard
     /// @def root
     /// Define items in the root of this {Linker}.
@@ -105,6 +124,10 @@ impl Linker {
         store: Obj<Store>,
         component: &Component,
     ) -> Result<Instance, Error> {
+        if *rb_self.has_wasi.borrow() && !store.context().data().has_wasi_ctx() {
+            return err!("{}", errors::missing_wasi_ctx_error("linker.instantiate"));
+        }
+
         let inner = rb_self.inner.borrow();
         inner
             .instantiate(store.context_mut(), component.get())
@@ -119,6 +142,12 @@ impl Linker {
             })
             .map_err(|e| error!("{}", e))
     }
+
+    pub(crate) fn add_wasi_p2(&self) -> Result<(), Error> {
+        *self.has_wasi.borrow_mut() = true;
+        let mut inner = self.inner.borrow_mut();
+        wasmtime_wasi::p2::add_to_linker_sync(&mut inner).map_err(|e| error!("{e}"))
+    }
 }
 
 /// @yard

ext/src/ruby_api/component/wasi_command.rs

@@ -0,0 +1,58 @@
+use magnus::{
+    class, function, method, module::Module, typed_data::Obj, DataTypeFunctions, Error, Object,
+    RModule, Ruby,
+};
+use wasmtime_wasi::p2::bindings::sync::Command;
+
+use crate::{
+    err, error,
+    ruby_api::{
+        component::{linker::Linker, Component},
+        errors,
+    },
+    Store,
+};
+
+#[magnus::wrap(class = "Wasmtime::Component::WasiCommand", size, free_immediately)]
+pub struct WasiCommand {
+    command: Command,
+}
+
+impl WasiCommand {
+    /// @yard
+    /// @def new(store, component, linker)
+    /// @param store [Store]
+    /// @param component [Component]
+    /// @param linker [Linker]
+    /// @return [WasiCommand]
+    pub fn new(store: &Store, component: &Component, linker: &Linker) -> Result<Self, Error> {
+        if linker.has_wasi() && !store.context().data().has_wasi_ctx() {
+            return err!("{}", errors::missing_wasi_ctx_error("WasiCommand.new"));
+        }
+        let command =
+            Command::instantiate(store.context_mut(), component.get(), &linker.inner_mut())
+                .map_err(|e| error!("{e}"))?;
+        Ok(Self { command })
+    }
+
+    /// @yard
+    /// @def call_run(store)
+    /// @param store [Store]
+    /// @return [nil]
+    pub fn call_run(_ruby: &Ruby, rb_self: Obj<Self>, store: &Store) -> Result<(), Error> {
+        rb_self
+            .command
+            .wasi_cli_run()
+            .call_run(store.context_mut())
+            .map_err(|err| error!("{err}"))?
+            .map_err(|_| error!("Error running `run`"))
+    }
+}
+
+pub fn init(_ruby: &Ruby, namespace: &RModule) -> Result<(), Error> {
+    let linker = namespace.define_class("WasiCommand", class::object())?;
+    linker.define_singleton_method("new", function!(WasiCommand::new, 3))?;
+    linker.define_method("call_run", method!(WasiCommand::call_run, 1))?;
+
+    Ok(())
+}

ext/src/ruby_api/errors.rs

@@ -83,6 +83,29 @@ impl ExceptionMessage for magnus::Error {
     }
 }
 
+pub(crate) fn missing_wasi_ctx_error(callee: &str) -> String {
+    missing_wasi_error(callee, "WASI", "P2", "wasi_config")
+}
+
+pub(crate) fn missing_wasi_p1_ctx_error() -> String {
+    missing_wasi_error("linker.instantiate", "WASI p1", "P1", "wasi_p1_config")
+}
+
+fn missing_wasi_error(
+    callee: &str,
+    wasi_text: &str,
+    add_wasi_call: &str,
+    option_name: &str,
+) -> String {
+    format!(
+        "Store is missing {wasi_text} configuration.\n\n\
+        When using `WASI::{add_wasi_call}::add_to_linker_sync(linker)`, the Store given to\n\
+        `{callee}` must have a {wasi_text} configuration.\n\
+        To fix this, provide the `{option_name}` when creating the Store:\n\
+            Wasmtime::Store.new(engine, {option_name}: WasiConfig.new)"
+    )
+}
+
 mod bundled {
     include!(concat!(env!("OUT_DIR"), "/bundled/error.rs"));
 }

ext/src/ruby_api/linker.rs

@@ -9,7 +9,7 @@ use super::{
     root,
     store::{Store, StoreContextValue, StoreData},
 };
-use crate::{define_rb_intern, err, error};
+use crate::{err, error, ruby_api::errors};
 use magnus::{
     block::Proc, class, function, gc::Marker, method, prelude::*, scan_args, scan_args::scan_args,
     typed_data::Obj, DataTypeFunctions, Error, Object, RArray, RHash, RString, Ruby, TypedData,
@@ -18,18 +18,14 @@ use magnus::{
 use std::cell::RefCell;
 use wasmtime::Linker as LinkerImpl;
 
-define_rb_intern!(
-    WASI=> "wasi",
-);
-
 /// @yard
 /// @see https://docs.rs/wasmtime/latest/wasmtime/struct.Linker.html Wasmtime's Rust doc
 #[derive(TypedData)]
 #[magnus(class = "Wasmtime::Linker", size, mark, free_immediately)]
 pub struct Linker {
     inner: RefCell<LinkerImpl<StoreData>>,
     refs: RefCell<Vec<Value>>,
-    has_wasi: bool,
+    has_wasi: RefCell<bool>,
 }
 
 unsafe impl Send for Linker {}
@@ -42,25 +38,15 @@ impl DataTypeFunctions for Linker {
 
 impl Linker {
     /// @yard
-    /// @def new(engine, wasi: false)
+    /// @def new(engine)
     /// @param engine [Engine]
-    /// @param wasi [Boolean] Whether WASI should be defined in this Linker. Defaults to false.
     /// @return [Linker]
-    pub fn new(args: &[Value]) -> Result<Self, Error> {
-        let args = scan_args::scan_args::<(&Engine,), (), (), (), _, ()>(args)?;
-        let kw = scan_args::get_kwargs::<_, (), (Option<bool>,), ()>(args.keywords, &[], &[*WASI])?;
-        let (engine,) = args.required;
-        let wasi = kw.optional.0.unwrap_or(false);
-
-        let mut inner: LinkerImpl<StoreData> = LinkerImpl::new(engine.get());
-        if wasi {
-            wasmtime_wasi::preview1::add_to_linker_sync(&mut inner, |s| s.wasi_ctx_mut())
-                .map_err(|e| error!("{}", e))?
-        }
+    pub fn new(engine: &Engine) -> Result<Self, Error> {
+        let inner: LinkerImpl<StoreData> = LinkerImpl::new(engine.get());
         Ok(Self {
             inner: RefCell::new(inner),
             refs: Default::default(),
-            has_wasi: wasi,
+            has_wasi: RefCell::new(false),
         })
     }
 
@@ -280,14 +266,8 @@ impl Linker {
     /// @param mod [Module]
     /// @return [Instance]
     pub fn instantiate(&self, store: Obj<Store>, module: &Module) -> Result<Instance, Error> {
-        if self.has_wasi && !store.context().data().has_wasi_ctx() {
-            return err!(
-                "Store is missing WASI configuration.\n\n\
-                When using `wasi: true`, the Store given to\n\
-                `Linker#instantiate` must have a WASI configuration.\n\
-                To fix this, provide the `wasi_config` when creating the Store:\n\
-                    Wasmtime::Store.new(engine, wasi_config: WasiConfig.new)"
-            );
+        if *self.has_wasi.borrow() && !store.context().data().has_wasi_p1_ctx() {
+            return err!("{}", errors::missing_wasi_p1_ctx_error());
         }
 
         self.inner
@@ -322,11 +302,18 @@ impl Linker {
         let mut inner = self.inner.borrow_mut();
         deterministic_wasi_ctx::replace_scheduling_functions(&mut inner).map_err(|e| error!("{e}"))
     }
+
+    pub(crate) fn add_wasi_p1(&self) -> Result<(), Error> {
+        *self.has_wasi.borrow_mut() = true;
+        let mut inner = self.inner.borrow_mut();
+        wasmtime_wasi::preview1::add_to_linker_sync(&mut inner, |s| s.wasi_p1_ctx_mut())
+            .map_err(|e| error!("{e}"))
+    }
 }
 
 pub fn init() -> Result<(), Error> {
     let class = root().define_class("Linker", class::object())?;
-    class.define_singleton_method("new", function!(Linker::new, -1))?;
+    class.define_singleton_method("new", function!(Linker::new, 1))?;
     class.define_method("allow_shadowing=", method!(Linker::set_allow_shadowing, 1))?;
     class.define_method(
         "allow_unknown_exports=",

ext/src/ruby_api/mod.rs

@@ -27,6 +27,7 @@ mod pooling_allocation_config;
 mod store;
 mod table;
 mod trap;
+mod wasi;
 mod wasi_config;
 
 pub use caller::Caller;
@@ -83,6 +84,7 @@ pub fn init(ruby: &Ruby) -> Result<(), Error> {
     memory::init(ruby)?;
     linker::init()?;
     externals::init()?;
+    wasi::init()?;
     wasi_config::init()?;
     table::init()?;
     global::init()?;