run_make_support: rename Command::stdin to stdin_buf and add std{in,out,err} config helpers

Previously `Command::stdin` was actually just a stdin buffer helper, but
this is different from `std::process::Command::stdin`. This is
needlessly confusing, and blocks support to add `std{in,out,err}` config
that tests may want to use to e.g. redirect to `/dev/ptmx`.

src/tools/run-make-support/src/command.rs

@@ -29,7 +29,14 @@
 #[derive(Debug)]
 pub struct Command {
     cmd: StdCommand,
-    stdin: Option<Box<[u8]>>,
+    // Convience for providing a quick stdin buffer.
+    stdin_buf: Option<Box<[u8]>>,
+
+    // Configurations for child process's std{in,out,err} handles.
+    stdin: Option<Stdio>,
+    stdout: Option<Stdio>,
+    stderr: Option<Stdio>,
+
     drop_bomb: DropBomb,
 }
 
@@ -37,12 +44,43 @@ impl Command {
     #[track_caller]
     pub fn new<P: AsRef<OsStr>>(program: P) -> Self {
         let program = program.as_ref();
-        Self { cmd: StdCommand::new(program), stdin: None, drop_bomb: DropBomb::arm(program) }
+        Self {
+            cmd: StdCommand::new(program),
+            stdin_buf: None,
+            drop_bomb: DropBomb::arm(program),
+            stdin: None,
+            stdout: None,
+            stderr: None,
+        }
     }
 
-    /// Specify a stdin input
-    pub fn stdin<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
-        self.stdin = Some(input.as_ref().to_vec().into_boxed_slice());
+    /// Specify a stdin input buffer. This is a convenience helper,
+    pub fn stdin_buf<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
+        self.stdin_buf = Some(input.as_ref().to_vec().into_boxed_slice());
+        self
+    }
+
+    /// Configuration for the child process’s standard input (stdin) handle.
+    ///
+    /// See [`std::process::Command::stdin`].
+    pub fn stdin<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Self {
+        self.stdin = Some(cfg.into());
+        self
+    }
+
+    /// Configuration for the child process’s standard output (stdout) handle.
+    ///
+    /// See [`std::process::Command::stdout`].
+    pub fn stdout<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Self {
+        self.stdout = Some(cfg.into());
+        self
+    }
+
+    /// Configuration for the child process’s standard error (stderr) handle.
+    ///
+    /// See [`std::process::Command::stderr`].
+    pub fn stderr<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Self {
+        self.stderr = Some(cfg.into());
         self
     }
 
@@ -105,6 +143,8 @@ pub fn current_dir<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
     }
 
     /// Run the constructed command and assert that it is successfully run.
+    ///
+    /// By default, std{in,out,err} are [`Stdio::piped()`].
     #[track_caller]
     pub fn run(&mut self) -> CompletedProcess {
         let output = self.command_output();
@@ -115,6 +155,8 @@ pub fn run(&mut self) -> CompletedProcess {
     }
 
     /// Run the constructed command and assert that it does not successfully run.
+    ///
+    /// By default, std{in,out,err} are [`Stdio::piped()`].
     #[track_caller]
     pub fn run_fail(&mut self) -> CompletedProcess {
         let output = self.command_output();
@@ -124,10 +166,10 @@ pub fn run_fail(&mut self) -> CompletedProcess {
         output
     }
 
-    /// Run the command but do not check its exit status.
-    /// Only use if you explicitly don't care about the exit status.
-    /// Prefer to use [`Self::run`] and [`Self::run_fail`]
-    /// whenever possible.
+    /// Run the command but do not check its exit status. Only use if you explicitly don't care
+    /// about the exit status.
+    ///
+    /// Prefer to use [`Self::run`] and [`Self::run_fail`] whenever possible.
     #[track_caller]
     pub fn run_unchecked(&mut self) -> CompletedProcess {
         self.command_output()
@@ -137,11 +179,11 @@ pub fn run_unchecked(&mut self) -> CompletedProcess {
     fn command_output(&mut self) -> CompletedProcess {
         self.drop_bomb.defuse();
         // let's make sure we piped all the input and outputs
-        self.cmd.stdin(Stdio::piped());
-        self.cmd.stdout(Stdio::piped());
-        self.cmd.stderr(Stdio::piped());
+        self.cmd.stdin(self.stdin.take().unwrap_or(Stdio::piped()));
+        self.cmd.stdout(self.stdout.take().unwrap_or(Stdio::piped()));
+        self.cmd.stderr(self.stderr.take().unwrap_or(Stdio::piped()));
 
-        let output = if let Some(input) = &self.stdin {
+        let output = if let Some(input) = &self.stdin_buf {
             let mut child = self.cmd.spawn().unwrap();
 
             {

src/tools/run-make-support/src/external_deps/llvm.rs

@@ -227,9 +227,10 @@ pub fn new() -> Self {
         Self { cmd }
     }
 
-    /// Pipe a read file into standard input containing patterns that will be matched against the .patterns(path) call.
-    pub fn stdin<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
-        self.cmd.stdin(input);
+    /// Provide a buffer representing standard input containing patterns that will be matched
+    /// against the `.patterns(path)` call.
+    pub fn stdin_buf<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
+        self.cmd.stdin_buf(input);
         self
     }
 

src/tools/run-make-support/src/external_deps/rustc.rs

@@ -291,9 +291,9 @@ pub fn link_args(&mut self, link_args: &str) -> &mut Self {
         self
     }
 
-    /// Specify a stdin input
-    pub fn stdin<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
-        self.cmd.stdin(input);
+    /// Specify a stdin input buffer.
+    pub fn stdin_buf<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
+        self.cmd.stdin_buf(input);
         self
     }
 

src/tools/run-make-support/src/external_deps/rustdoc.rs

@@ -85,9 +85,9 @@ pub fn arg_file<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
         self
     }
 
-    /// Specify a stdin input
-    pub fn stdin<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
-        self.cmd.stdin(input);
+    /// Specify a stdin input buffer.
+    pub fn stdin_buf<I: AsRef<[u8]>>(&mut self, input: I) -> &mut Self {
+        self.cmd.stdin_buf(input);
         self
     }
 

src/tools/run-make-support/src/lib.rs

@@ -34,6 +34,7 @@ pub mod rfs {
 }
 
 // Re-exports of third-party library crates.
+// tidy-alphabetical-start
 pub use bstr;
 pub use gimli;
 pub use libc;
@@ -41,6 +42,7 @@ pub mod rfs {
 pub use regex;
 pub use serde_json;
 pub use wasmparser;
+// tidy-alphabetical-end
 
 // Re-exports of external dependencies.
 pub use external_deps::{c_build, cc, clang, htmldocck, llvm, python, rustc, rustdoc};