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

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
     }
 }