only wasi_cap_std_sync and wasi_tokio need to define WasiCtxBuilders (#2917)

* wasmtime-wasi: re-exporting this WasiCtxBuilder was shadowing the right one

wasi-common's WasiCtxBuilder is really only useful wasi_cap_std_sync and
wasi_tokio to implement their own Builder on top of.

This re-export of wasi-common's is 1. not useful and 2. shadow's the
re-export of the right one in sync::*.

* wasi-common: eliminate WasiCtxBuilder, make the builder methods on WasiCtx instead

* delete wasi-common::WasiCtxBuilder altogether

just put those methods directly on &mut WasiCtx.

As a bonus, the sync and tokio WasiCtxBuilder::build functions
are no longer fallible!

* bench fixes

* more test fixes

benches/instantiation.rs

@@ -11,7 +11,7 @@ fn instantiate(module: &Module) -> Result<Instance> {
     // As we don't actually invoke Wasm code in this benchmark, we still add
     // the WASI context to the store as it is considered part of getting a
     // module that depends on WASI "ready to run".
-    Wasi::set_context(&store, WasiCtxBuilder::new().build()?)
+    Wasi::set_context(&store, WasiCtxBuilder::new().build())
         .map_err(|_| anyhow::anyhow!("wasi set_context failed"))?;
 
     let linker = Linker::new(&store);

crates/bench-api/src/lib.rs

@@ -222,7 +222,7 @@ impl BenchState {
             cx = cx.env("WASM_BENCH_USE_SMALL_WORKLOAD", &val)?;
         }
 
-        Wasi::new(linker.store(), cx.build()?).add_to_linker(&mut linker)?;
+        Wasi::new(linker.store(), cx.build()).add_to_linker(&mut linker)?;
 
         #[cfg(feature = "wasi-nn")]
         {

crates/c-api/src/wasi.rs

@@ -254,7 +254,7 @@ fn create_wasi_ctx(config: wasi_config_t) -> Result<Rc<RefCell<WasiCtx>>> {
     for (dir, path) in config.preopens {
         builder = builder.preopened_dir(dir, path)?;
     }
-    Ok(Rc::new(RefCell::new(builder.build()?)))
+    Ok(Rc::new(RefCell::new(builder.build())))
 }
 
 #[repr(C)]

crates/misc/rust/macro/src/lib.rs

@@ -61,7 +61,7 @@ fn generate_load(item: &syn::ItemTrait) -> syn::Result<TokenStream> {
 
             let mut imports: Vec<Extern> = Vec::new();
             if let Some(module_name) = data.find_wasi_module_name() {
-                let wasi_cx = #root::wasmtime_wasi::WasiCtxBuilder::new().build()?;
+                let wasi_cx = #root::wasmtime_wasi::WasiCtxBuilder::new().build();
                 let wasi = #root::wasmtime_wasi::Wasi::new(&store, wasi_cx);
                 for i in module.imports().iter() {
                     if i.module() != module_name {

crates/test-programs/tests/wasm_tests/runtime/cap_std_sync.rs

@@ -53,7 +53,7 @@ fn run(
         // cap-std-sync does not yet support the sync family of fdflags
         builder = builder.env("NO_FDFLAGS_SYNC_SUPPORT", "1")?;
 
-        let wasi = Wasi::new(&store, builder.build()?);
+        let wasi = Wasi::new(&store, builder.build());
 
         let mut linker = Linker::new(&store);
 

crates/test-programs/tests/wasm_tests/runtime/tokio.rs

@@ -62,7 +62,7 @@ fn run(
             // does not.
             builder = builder.env("NO_FDFLAGS_SYNC_SUPPORT", "1")?;
 
-            Wasi::set_context(&store, builder.build()?)
+            Wasi::set_context(&store, builder.build())
                 .map_err(|_| anyhow::anyhow!("wasi set_context failed"))?;
 
             let module =

crates/wasi-common/cap-std-sync/src/lib.rs

@@ -47,61 +47,60 @@ use std::path::Path;
 use std::rc::Rc;
 use wasi_common::{table::Table, Error, WasiCtx, WasiFile};
 
-pub struct WasiCtxBuilder(wasi_common::WasiCtxBuilder);
+pub struct WasiCtxBuilder(WasiCtx);
 
 impl WasiCtxBuilder {
     pub fn new() -> Self {
-        WasiCtxBuilder(WasiCtx::builder(
+        WasiCtxBuilder(WasiCtx::new(
             random_ctx(),
             clocks_ctx(),
             sched_ctx(),
             Rc::new(RefCell::new(Table::new())),
         ))
     }
-    pub fn env(self, var: &str, value: &str) -> Result<Self, wasi_common::StringArrayError> {
-        let s = self.0.env(var, value)?;
-        Ok(WasiCtxBuilder(s))
+    pub fn env(mut self, var: &str, value: &str) -> Result<Self, wasi_common::StringArrayError> {
+        self.0.push_env(var, value)?;
+        Ok(self)
     }
-    pub fn envs(self, env: &[(String, String)]) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self;
+    pub fn envs(mut self, env: &[(String, String)]) -> Result<Self, wasi_common::StringArrayError> {
         for (k, v) in env {
-            s = s.env(k, v)?;
+            self.0.push_env(k, v)?;
         }
-        Ok(s)
+        Ok(self)
     }
-    pub fn inherit_env(self) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self.0;
+    pub fn inherit_env(mut self) -> Result<Self, wasi_common::StringArrayError> {
         for (key, value) in std::env::vars() {
-            s = s.env(&key, &value)?;
+            self.0.push_env(&key, &value)?;
         }
-        Ok(WasiCtxBuilder(s))
+        Ok(self)
     }
-    pub fn arg(self, arg: &str) -> Result<Self, wasi_common::StringArrayError> {
-        let s = self.0.arg(arg)?;
-        Ok(WasiCtxBuilder(s))
+    pub fn arg(mut self, arg: &str) -> Result<Self, wasi_common::StringArrayError> {
+        self.0.push_arg(arg)?;
+        Ok(self)
     }
-    pub fn args(self, arg: &[String]) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self;
+    pub fn args(mut self, arg: &[String]) -> Result<Self, wasi_common::StringArrayError> {
         for a in arg {
-            s = s.arg(&a)?;
+            self.0.push_arg(&a)?;
         }
-        Ok(s)
+        Ok(self)
     }
-    pub fn inherit_args(self) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self.0;
+    pub fn inherit_args(mut self) -> Result<Self, wasi_common::StringArrayError> {
         for arg in std::env::args() {
-            s = s.arg(&arg)?;
+            self.0.push_arg(&arg)?;
         }
-        Ok(WasiCtxBuilder(s))
+        Ok(self)
     }
-    pub fn stdin(self, f: Box<dyn WasiFile>) -> Self {
-        WasiCtxBuilder(self.0.stdin(f))
+    pub fn stdin(mut self, f: Box<dyn WasiFile>) -> Self {
+        self.0.set_stdin(f);
+        self
     }
-    pub fn stdout(self, f: Box<dyn WasiFile>) -> Self {
-        WasiCtxBuilder(self.0.stdout(f))
+    pub fn stdout(mut self, f: Box<dyn WasiFile>) -> Self {
+        self.0.set_stdout(f);
+        self
     }
-    pub fn stderr(self, f: Box<dyn WasiFile>) -> Self {
-        WasiCtxBuilder(self.0.stderr(f))
+    pub fn stderr(mut self, f: Box<dyn WasiFile>) -> Self {
+        self.0.set_stderr(f);
+        self
     }
     pub fn inherit_stdin(self) -> Self {
         self.stdin(Box::new(crate::stdio::stdin()))
@@ -115,12 +114,13 @@ impl WasiCtxBuilder {
     pub fn inherit_stdio(self) -> Self {
         self.inherit_stdin().inherit_stdout().inherit_stderr()
     }
-    pub fn preopened_dir(self, dir: Dir, guest_path: impl AsRef<Path>) -> Result<Self, Error> {
+    pub fn preopened_dir(mut self, dir: Dir, guest_path: impl AsRef<Path>) -> Result<Self, Error> {
         let dir = Box::new(crate::dir::Dir::from_cap_std(dir));
-        Ok(WasiCtxBuilder(self.0.preopened_dir(dir, guest_path)?))
+        self.0.push_preopened_dir(dir, guest_path)?;
+        Ok(self)
     }
-    pub fn build(self) -> Result<WasiCtx, Error> {
-        self.0.build()
+    pub fn build(self) -> WasiCtx {
+        self.0
     }
 }
 

crates/wasi-common/src/ctx.rs

@@ -20,20 +20,24 @@ pub struct WasiCtx {
 }
 
 impl WasiCtx {
-    pub fn builder(
+    pub fn new(
         random: RefCell<Box<dyn RngCore>>,
         clocks: WasiClocks,
         sched: Box<dyn WasiSched>,
         table: Rc<RefCell<Table>>,
-    ) -> WasiCtxBuilder {
-        WasiCtxBuilder(WasiCtx {
+    ) -> Self {
+        let mut s = WasiCtx {
             args: StringArray::new(),
             env: StringArray::new(),
             random,
             clocks,
             sched,
             table,
-        })
+        };
+        s.set_stdin(Box::new(crate::pipe::ReadPipe::new(std::io::empty())));
+        s.set_stdout(Box::new(crate::pipe::WritePipe::new(std::io::sink())));
+        s.set_stderr(Box::new(crate::pipe::WritePipe::new(std::io::sink())));
+        s
     }
 
     pub fn insert_file(&self, fd: u32, file: Box<dyn WasiFile>, caps: FileCaps) {
@@ -58,67 +62,41 @@ impl WasiCtx {
     pub fn table(&self) -> RefMut<Table> {
         self.table.borrow_mut()
     }
-}
-
-pub struct WasiCtxBuilder(WasiCtx);
-
-impl WasiCtxBuilder {
-    pub fn build(self) -> Result<WasiCtx, Error> {
-        use crate::file::TableFileExt;
-        // Default to an empty readpipe for stdin:
-        if self.0.table().get_file(0).is_err() {
-            let stdin = crate::pipe::ReadPipe::new(std::io::empty());
-            self.0.insert_file(0, Box::new(stdin), FileCaps::all());
-        }
-        // Default to a sink writepipe for stdout, stderr:
-        for stdio_write in &[1, 2] {
-            if self.0.table().get_file(*stdio_write).is_err() {
-                let output_file = crate::pipe::WritePipe::new(std::io::sink());
-                self.0
-                    .insert_file(*stdio_write, Box::new(output_file), FileCaps::all());
-            }
-        }
-        Ok(self.0)
-    }
 
-    pub fn arg(mut self, arg: &str) -> Result<Self, StringArrayError> {
-        self.0.args.push(arg.to_owned())?;
-        Ok(self)
+    pub fn push_arg(&mut self, arg: &str) -> Result<(), StringArrayError> {
+        self.args.push(arg.to_owned())
     }
 
-    pub fn env(mut self, var: &str, value: &str) -> Result<Self, StringArrayError> {
-        self.0.env.push(format!("{}={}", var, value))?;
-        Ok(self)
+    pub fn push_env(&mut self, var: &str, value: &str) -> Result<(), StringArrayError> {
+        self.env.push(format!("{}={}", var, value))?;
+        Ok(())
     }
 
-    pub fn stdin(self, f: Box<dyn WasiFile>) -> Self {
-        self.0.insert_file(0, f, FileCaps::all());
-        self
+    pub fn set_stdin(&mut self, f: Box<dyn WasiFile>) {
+        self.insert_file(0, f, FileCaps::all());
     }
 
-    pub fn stdout(self, f: Box<dyn WasiFile>) -> Self {
-        self.0.insert_file(1, f, FileCaps::all());
-        self
+    pub fn set_stdout(&mut self, f: Box<dyn WasiFile>) {
+        self.insert_file(1, f, FileCaps::all());
     }
 
-    pub fn stderr(self, f: Box<dyn WasiFile>) -> Self {
-        self.0.insert_file(2, f, FileCaps::all());
-        self
+    pub fn set_stderr(&mut self, f: Box<dyn WasiFile>) {
+        self.insert_file(2, f, FileCaps::all());
     }
 
-    pub fn preopened_dir(
-        self,
+    pub fn push_preopened_dir(
+        &mut self,
         dir: Box<dyn WasiDir>,
         path: impl AsRef<Path>,
-    ) -> Result<Self, Error> {
+    ) -> Result<(), Error> {
         let caps = DirCaps::all();
         let file_caps = FileCaps::all();
-        self.0.table().push(Box::new(DirEntry::new(
+        self.table().push(Box::new(DirEntry::new(
             caps,
             file_caps,
             Some(path.as_ref().to_owned()),
             dir,
         )))?;
-        Ok(self)
+        Ok(())
     }
 }

crates/wasi-common/src/lib.rs

@@ -64,7 +64,7 @@ pub mod table;
 
 pub use cap_rand::RngCore;
 pub use clocks::{SystemTimeSpec, WasiClocks, WasiMonotonicClock, WasiSystemClock};
-pub use ctx::{WasiCtx, WasiCtxBuilder};
+pub use ctx::WasiCtx;
 pub use dir::WasiDir;
 pub use error::{Context, Error, ErrorExt, ErrorKind};
 pub use file::WasiFile;

crates/wasi-common/src/pipe.rs

@@ -32,9 +32,8 @@ use std::sync::{Arc, RwLock};
 /// let clocks = todo!();
 /// let sched = todo!();
 /// let table = Rc::new(RefCell::new(Table::new()));
-/// let ctx = WasiCtx::builder(random, clocks, sched, table)
-///             .stdin(Box::new(stdin.clone()))
-///             .build();
+/// let mut ctx = WasiCtx::new(random, clocks, sched, table);
+/// ctx.set_stdin(Box::new(stdin.clone()));
 /// ```
 #[derive(Debug)]
 pub struct ReadPipe<R: Read> {
@@ -203,9 +202,8 @@ impl<R: Read + Any + Send + Sync> WasiFile for ReadPipe<R> {
 /// let clocks = todo!();
 /// let sched = todo!();
 /// let table = Rc::new(RefCell::new(Table::new()));
-/// let ctx = WasiCtx::builder(random, clocks, sched, table)
-///             .stdout(Box::new(stdout.clone()))
-///             .build();
+/// let mut ctx = WasiCtx::new(random, clocks, sched, table);
+/// ctx.set_stdout(Box::new(stdout.clone()));
 /// // use ctx in an instance, then make sure it is dropped:
 /// drop(ctx);
 /// let contents: Vec<u8> = stdout.try_into_inner().expect("sole remaining reference to WritePipe").into_inner();

crates/wasi-common/tokio/src/lib.rs

@@ -8,68 +8,67 @@ use std::future::Future;
 use std::path::Path;
 use std::rc::Rc;
 pub use wasi_cap_std_sync::{clocks_ctx, random_ctx};
-use wasi_common::{Error, Table, WasiCtx};
+use wasi_common::{Error, Table, WasiCtx, WasiFile};
 
 pub use dir::Dir;
 pub use file::File;
 
 use crate::sched::sched_ctx;
 
-pub struct WasiCtxBuilder(wasi_common::WasiCtxBuilder);
+pub struct WasiCtxBuilder(WasiCtx);
 
 impl WasiCtxBuilder {
     pub fn new() -> Self {
-        WasiCtxBuilder(WasiCtx::builder(
+        WasiCtxBuilder(WasiCtx::new(
             random_ctx(),
             clocks_ctx(),
             sched_ctx(),
             Rc::new(RefCell::new(Table::new())),
         ))
     }
-    pub fn env(self, var: &str, value: &str) -> Result<Self, wasi_common::StringArrayError> {
-        let s = self.0.env(var, value)?;
-        Ok(WasiCtxBuilder(s))
+    pub fn env(mut self, var: &str, value: &str) -> Result<Self, wasi_common::StringArrayError> {
+        self.0.push_env(var, value)?;
+        Ok(self)
     }
-    pub fn envs(self, env: &[(String, String)]) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self;
+    pub fn envs(mut self, env: &[(String, String)]) -> Result<Self, wasi_common::StringArrayError> {
         for (k, v) in env {
-            s = s.env(k, v)?;
+            self.0.push_env(k, v)?;
         }
-        Ok(s)
+        Ok(self)
     }
-    pub fn inherit_env(self) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self.0;
+    pub fn inherit_env(mut self) -> Result<Self, wasi_common::StringArrayError> {
         for (key, value) in std::env::vars() {
-            s = s.env(&key, &value)?;
+            self.0.push_env(&key, &value)?;
         }
-        Ok(WasiCtxBuilder(s))
+        Ok(self)
     }
-    pub fn arg(self, arg: &str) -> Result<Self, wasi_common::StringArrayError> {
-        let s = self.0.arg(arg)?;
-        Ok(WasiCtxBuilder(s))
+    pub fn arg(mut self, arg: &str) -> Result<Self, wasi_common::StringArrayError> {
+        self.0.push_arg(arg)?;
+        Ok(self)
     }
-    pub fn args(self, arg: &[String]) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self;
+    pub fn args(mut self, arg: &[String]) -> Result<Self, wasi_common::StringArrayError> {
         for a in arg {
-            s = s.arg(&a)?;
+            self.0.push_arg(&a)?;
         }
-        Ok(s)
+        Ok(self)
     }
-    pub fn inherit_args(self) -> Result<Self, wasi_common::StringArrayError> {
-        let mut s = self.0;
+    pub fn inherit_args(mut self) -> Result<Self, wasi_common::StringArrayError> {
         for arg in std::env::args() {
-            s = s.arg(&arg)?;
+            self.0.push_arg(&arg)?;
         }
-        Ok(WasiCtxBuilder(s))
+        Ok(self)
     }
-    pub fn stdin(self, f: Box<dyn wasi_common::WasiFile>) -> Self {
-        WasiCtxBuilder(self.0.stdin(f))
+    pub fn stdin(mut self, f: Box<dyn WasiFile>) -> Self {
+        self.0.set_stdin(f);
+        self
     }
-    pub fn stdout(self, f: Box<dyn wasi_common::WasiFile>) -> Self {
-        WasiCtxBuilder(self.0.stdout(f))
+    pub fn stdout(mut self, f: Box<dyn WasiFile>) -> Self {
+        self.0.set_stdout(f);
+        self
     }
-    pub fn stderr(self, f: Box<dyn wasi_common::WasiFile>) -> Self {
-        WasiCtxBuilder(self.0.stderr(f))
+    pub fn stderr(mut self, f: Box<dyn WasiFile>) -> Self {
+        self.0.set_stderr(f);
+        self
     }
     pub fn inherit_stdin(self) -> Self {
         self.stdin(Box::new(crate::stdio::stdin()))
@@ -84,15 +83,16 @@ impl WasiCtxBuilder {
         self.inherit_stdin().inherit_stdout().inherit_stderr()
     }
     pub fn preopened_dir(
-        self,
+        mut self,
         dir: cap_std::fs::Dir,
         guest_path: impl AsRef<Path>,
-    ) -> Result<Self, wasi_common::Error> {
-        let dir = Box::new(Dir::from_cap_std(dir));
-        Ok(WasiCtxBuilder(self.0.preopened_dir(dir, guest_path)?))
+    ) -> Result<Self, Error> {
+        let dir = Box::new(crate::dir::Dir::from_cap_std(dir));
+        self.0.push_preopened_dir(dir, guest_path)?;
+        Ok(self)
     }
-    pub fn build(self) -> Result<WasiCtx, wasi_common::Error> {
-        self.0.build()
+    pub fn build(self) -> WasiCtx {
+        self.0
     }
 }
 

crates/wasi/src/lib.rs

@@ -7,7 +7,7 @@
 //! Individual snapshots are available through
 //! `wasmtime_wasi::snapshots::preview_{0, 1}::Wasi::new(&Store, Rc<RefCell<WasiCtx>>)`.
 
-pub use wasi_common::{Error, WasiCtx, WasiCtxBuilder, WasiDir, WasiFile};
+pub use wasi_common::{Error, WasiCtx, WasiDir, WasiFile};
 
 /// Re-export the commonly used wasi-cap-std-sync crate here. This saves
 /// consumers of this library from having to keep additional dependencies

crates/wasmtime/src/lib.rs

@@ -202,7 +202,7 @@
 //! // Create an instance of `Wasi` which contains a `WasiCtx`. Note that
 //! // `WasiCtx` provides a number of ways to configure what the target program
 //! // will have access to.
-//! let wasi = Wasi::new(&store, WasiCtxBuilder::new().inherit_stdio().build()?);
+//! let wasi = Wasi::new(&store, WasiCtxBuilder::new().inherit_stdio().build());
 //! wasi.add_to_linker(&mut linker)?;
 //!
 //! // Instantiate our module with the imports we've created, and run it.

examples/linking.rs

@@ -18,7 +18,7 @@ fn main() -> Result<()> {
         WasiCtxBuilder::new()
             .inherit_stdio()
             .inherit_args()?
-            .build()?,
+            .build(),
     );
     wasi.add_to_linker(&mut linker)?;
 

examples/tokio/main.rs

@@ -146,7 +146,7 @@ async fn _run_wasm(inputs: Inputs) -> Result<(), Error> {
             .inherit_stdout()
             // Set an environment variable so the wasm knows its name.
             .env("NAME", &inputs.name)?
-            .build()?,
+            .build(),
     )
     .map_err(|_| anyhow!("setting wasi context"))?;
 

examples/wasi/main.rs

@@ -27,7 +27,7 @@ fn main() -> Result<()> {
         WasiCtxBuilder::new()
             .inherit_stdio()
             .inherit_args()?
-            .build()?
+            .build()
     )
     .is_ok());
 

src/commands/run.rs

@@ -371,7 +371,7 @@ fn populate_with_wasi(
     }
 
     if wasi_modules.wasi_common {
-        Wasi::new(linker.store(), builder.build()?).add_to_linker(linker)?;
+        Wasi::new(linker.store(), builder.build()).add_to_linker(linker)?;
     }
 
     if wasi_modules.wasi_nn {

tests/all/host_funcs.rs

@@ -757,7 +757,7 @@ fn wasi_imports() -> Result<()> {
     let engine = Engine::new(&config)?;
     let module = Module::new(&engine, wasm)?;
     let store = Store::new(&engine);
-    assert!(Wasi::set_context(&store, WasiCtxBuilder::new().build()?).is_ok());
+    assert!(Wasi::set_context(&store, WasiCtxBuilder::new().build()).is_ok());
     let linker = Linker::new(&store);
     let instance = linker.instantiate(&module)?;
 

tests/all/traps.rs

@@ -500,7 +500,7 @@ fn parse_dwarf_info() -> Result<()> {
         &store,
         wasmtime_wasi::sync::WasiCtxBuilder::new()
             .inherit_stdio()
-            .build()?,
+            .build(),
     )
     .add_to_linker(&mut linker)?;
     linker.module("", &module)?;