reorganize

1 files changed, 266 insertions, 0 deletions

diff --git a/src/pipeline/builtins/command.rs b/src/pipeline/builtins/command.rs
new file mode 100644
index 0000000..b49b41d
--- /dev/null
+++ b/src/pipeline/builtins/command.rs
@@ -0,0 +1,266 @@
+use async_std::io::{ReadExt as _, WriteExt as _};
+use std::os::unix::io::{AsRawFd as _, FromRawFd as _, IntoRawFd as _};
+
+pub struct Command {
+    exe: crate::parse::Exe,
+    f: super::Builtin,
+    io: Io,
+}
+
+impl Command {
+    pub fn new(exe: crate::parse::Exe) -> Result<Self, crate::parse::Exe> {
+        if let Some(f) = super::BUILTINS.get(exe.exe()) {
+            Ok(Self {
+                exe,
+                f,
+                io: Io::new(),
+            })
+        } else {
+            Err(exe)
+        }
+    }
+
+    pub fn stdin(&mut self, fh: std::fs::File) {
+        self.io.set_stdin(fh);
+    }
+
+    pub fn stdout(&mut self, fh: std::fs::File) {
+        self.io.set_stdout(fh);
+    }
+
+    pub fn stderr(&mut self, fh: std::fs::File) {
+        self.io.set_stderr(fh);
+    }
+
+    // Safety: see pre_exec in async_std::os::unix::process::CommandExt (this
+    // is just a wrapper)
+    pub unsafe fn pre_exec<F>(&mut self, f: F)
+    where
+        F: 'static + FnMut() -> std::io::Result<()> + Send + Sync,
+    {
+        self.io.pre_exec(f);
+    }
+
+    pub fn spawn(self, env: &crate::env::Env) -> anyhow::Result<Child> {
+        let Self { f, exe, io } = self;
+        (f)(exe, env, io)
+    }
+}
+
+pub struct Io {
+    fds: std::collections::HashMap<
+        std::os::unix::io::RawFd,
+        std::os::unix::io::RawFd,
+    >,
+    pre_exec: Option<
+        Box<dyn 'static + FnMut() -> std::io::Result<()> + Send + Sync>,
+    >,
+}
+
+impl Io {
+    fn new() -> Self {
+        let mut fds = std::collections::HashMap::new();
+        fds.insert(0.as_raw_fd(), 0.as_raw_fd());
+        fds.insert(1.as_raw_fd(), 1.as_raw_fd());
+        fds.insert(2.as_raw_fd(), 2.as_raw_fd());
+        Self {
+            fds,
+            pre_exec: None,
+        }
+    }
+
+    fn stdin(&self) -> Option<async_std::fs::File> {
+        self.fds
+            .get(&0.as_raw_fd())
+            .copied()
+            // Safety: TODO this is likely unsafe
+            .map(|fd| unsafe { async_std::fs::File::from_raw_fd(fd) })
+    }
+
+    fn set_stdin<T: std::os::unix::io::IntoRawFd>(&mut self, stdin: T) {
+        if let Some(fd) = self.fds.get(&0.as_raw_fd()) {
+            if *fd > 2 {
+                // Safety: TODO this is likely unsafe
+                drop(unsafe { async_std::fs::File::from_raw_fd(*fd) });
+            }
+        }
+        self.fds.insert(0.as_raw_fd(), stdin.into_raw_fd());
+    }
+
+    fn stdout(&self) -> Option<async_std::fs::File> {
+        self.fds
+            .get(&1.as_raw_fd())
+            .copied()
+            // Safety: TODO this is likely unsafe
+            .map(|fd| unsafe { async_std::fs::File::from_raw_fd(fd) })
+    }
+
+    fn set_stdout<T: std::os::unix::io::IntoRawFd>(&mut self, stdout: T) {
+        if let Some(fd) = self.fds.get(&1.as_raw_fd()) {
+            if *fd > 2 {
+                // Safety: TODO this is likely unsafe
+                drop(unsafe { async_std::fs::File::from_raw_fd(*fd) });
+            }
+        }
+        self.fds.insert(1.as_raw_fd(), stdout.into_raw_fd());
+    }
+
+    fn stderr(&self) -> Option<async_std::fs::File> {
+        self.fds
+            .get(&2.as_raw_fd())
+            .copied()
+            // Safety: TODO this is likely unsafe
+            .map(|fd| unsafe { async_std::fs::File::from_raw_fd(fd) })
+    }
+
+    fn set_stderr<T: std::os::unix::io::IntoRawFd>(&mut self, stderr: T) {
+        if let Some(fd) = self.fds.get(&2.as_raw_fd()) {
+            if *fd > 2 {
+                // Safety: TODO this is likely unsafe
+                drop(unsafe { async_std::fs::File::from_raw_fd(*fd) });
+            }
+        }
+        self.fds.insert(2.as_raw_fd(), stderr.into_raw_fd());
+    }
+
+    // Safety: see pre_exec in async_std::os::unix::process::CommandExt (this
+    // is just a wrapper)
+    pub unsafe fn pre_exec<F>(&mut self, f: F)
+    where
+        F: 'static + FnMut() -> std::io::Result<()> + Send + Sync,
+    {
+        self.pre_exec = Some(Box::new(f));
+    }
+
+    pub async fn read_stdin(&self, buf: &mut [u8]) -> anyhow::Result<usize> {
+        if let Some(mut fh) = self.stdin() {
+            let res = fh.read(buf).await;
+            let _ = fh.into_raw_fd();
+            Ok(res?)
+        } else {
+            Ok(0)
+        }
+    }
+
+    pub async fn write_stdout(&self, buf: &[u8]) -> anyhow::Result<()> {
+        if let Some(mut fh) = self.stdout() {
+            let res = fh.write_all(buf).await;
+            let _ = fh.into_raw_fd();
+            Ok(res.map(|_| ())?)
+        } else {
+            Ok(())
+        }
+    }
+
+    pub async fn write_stderr(&self, buf: &[u8]) -> anyhow::Result<()> {
+        if let Some(mut fh) = self.stderr() {
+            let res = fh.write_all(buf).await;
+            let _ = fh.into_raw_fd();
+            Ok(res.map(|_| ())?)
+        } else {
+            Ok(())
+        }
+    }
+
+    pub fn setup_command(mut self, cmd: &mut crate::pipeline::Command) {
+        if let Some(stdin) = self.stdin() {
+            let stdin = stdin.into_raw_fd();
+            if stdin != 0 {
+                // Safety: TODO this is likely unsafe
+                cmd.stdin(unsafe { std::fs::File::from_raw_fd(stdin) });
+                self.fds.remove(&0.as_raw_fd());
+            }
+        }
+        if let Some(stdout) = self.stdout() {
+            let stdout = stdout.into_raw_fd();
+            if stdout != 1 {
+                // Safety: TODO this is likely unsafe
+                cmd.stdout(unsafe { std::fs::File::from_raw_fd(stdout) });
+                self.fds.remove(&1.as_raw_fd());
+            }
+        }
+        if let Some(stderr) = self.stderr() {
+            let stderr = stderr.into_raw_fd();
+            if stderr != 2 {
+                // Safety: TODO this is likely unsafe
+                cmd.stderr(unsafe { std::fs::File::from_raw_fd(stderr) });
+                self.fds.remove(&2.as_raw_fd());
+            }
+        }
+        if let Some(pre_exec) = self.pre_exec.take() {
+            // Safety: pre_exec can only have been set by calling the pre_exec
+            // method, which is itself unsafe, so the safety comments at the
+            // point where that is called are the relevant ones
+            unsafe { cmd.pre_exec(pre_exec) };
+        }
+    }
+}
+
+impl Drop for Io {
+    fn drop(&mut self) {
+        for fd in self.fds.values() {
+            if *fd > 2 {
+                // Safety: TODO this is likely unsafe
+                drop(unsafe { std::fs::File::from_raw_fd(*fd) });
+            }
+        }
+    }
+}
+
+pub struct Child<'a> {
+    fut: std::pin::Pin<
+        Box<
+            dyn std::future::Future<Output = std::process::ExitStatus>
+                + Sync
+                + Send
+                + 'a,
+        >,
+    >,
+    wrapped_child: Option<Box<crate::pipeline::Child<'a>>>,
+}
+
+impl<'a> Child<'a> {
+    pub fn new_fut<F>(fut: F) -> Self
+    where
+        F: std::future::Future<Output = std::process::ExitStatus>
+            + Sync
+            + Send
+            + 'a,
+    {
+        Self {
+            fut: Box::pin(fut),
+            wrapped_child: None,
+        }
+    }
+
+    pub fn new_wrapped(child: crate::pipeline::Child<'a>) -> Self {
+        Self {
+            fut: Box::pin(async move { unreachable!() }),
+            wrapped_child: Some(Box::new(child)),
+        }
+    }
+
+    pub fn id(&self) -> Option<u32> {
+        self.wrapped_child.as_ref().and_then(|cmd| cmd.id())
+    }
+
+    pub fn status(
+        self,
+    ) -> std::pin::Pin<
+        Box<
+            dyn std::future::Future<
+                    Output = anyhow::Result<async_std::process::ExitStatus>,
+                > + Send
+                + Sync
+                + 'a,
+        >,
+    > {
+        Box::pin(async move {
+            if let Some(child) = self.wrapped_child {
+                child.status().await
+            } else {
+                Ok(self.fut.await)
+            }
+        })
+    }
+}