rename

since this doesn't just run pipelines anymore

1 files changed, 398 insertions, 0 deletions

diff --git a/src/runner/builtins/command.rs b/src/runner/builtins/command.rs
new file mode 100644
index 0000000..2c1f755
--- /dev/null
+++ b/src/runner/builtins/command.rs
@@ -0,0 +1,398 @@
+use crate::runner::prelude::*;
+
+use async_std::io::prelude::BufReadExt as _;
+
+pub struct Command {
+    exe: crate::parse::Exe,
+    f: super::Builtin,
+    cfg: Cfg,
+}
+
+impl Command {
+    pub fn new(exe: crate::parse::Exe) -> Result<Self, crate::parse::Exe> {
+        if let Some(s) = exe.exe().to_str() {
+            if let Some(f) = super::BUILTINS.get(s) {
+                Ok(Self {
+                    exe,
+                    f,
+                    cfg: Cfg::new(),
+                })
+            } else {
+                Err(exe)
+            }
+        } else {
+            Err(exe)
+        }
+    }
+
+    pub fn new_with_io(
+        exe: crate::parse::Exe,
+        io: Io,
+    ) -> Result<Self, crate::parse::Exe> {
+        if let Some(s) = exe.exe().to_str() {
+            if let Some(f) = super::BUILTINS.get(s) {
+                Ok(Self {
+                    exe,
+                    f,
+                    cfg: Cfg::new_with_io(io),
+                })
+            } else {
+                Err(exe)
+            }
+        } else {
+            Err(exe)
+        }
+    }
+
+    pub fn stdin(&mut self, fh: std::fs::File) {
+        self.cfg.io.set_stdin(fh);
+    }
+
+    pub fn stdout(&mut self, fh: std::fs::File) {
+        self.cfg.io.set_stdout(fh);
+    }
+
+    pub fn stderr(&mut self, fh: std::fs::File) {
+        self.cfg.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.cfg.pre_exec(f);
+    }
+
+    pub fn apply_redirects(&mut self, redirects: &[crate::parse::Redirect]) {
+        self.cfg.io.apply_redirects(redirects);
+    }
+
+    pub fn spawn(self, env: &Env) -> anyhow::Result<Child> {
+        let Self { f, exe, cfg } = self;
+        (f)(exe, env, cfg)
+    }
+}
+
+pub struct Cfg {
+    io: Io,
+    pre_exec: Option<
+        Box<dyn 'static + FnMut() -> std::io::Result<()> + Send + Sync>,
+    >,
+}
+
+impl Cfg {
+    fn new() -> Self {
+        Self {
+            io: Io::new(),
+            pre_exec: None,
+        }
+    }
+
+    fn new_with_io(io: Io) -> Self {
+        Self { io, pre_exec: None }
+    }
+
+    pub fn io(&self) -> &Io {
+        &self.io
+    }
+
+    // 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 fn setup_command(mut self, cmd: &mut crate::runner::Command) {
+        self.io.setup_command(cmd);
+        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) };
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Io {
+    fds: std::collections::HashMap<
+        std::os::unix::io::RawFd,
+        crate::mutex::Mutex<File>,
+    >,
+}
+
+impl Io {
+    pub fn new() -> Self {
+        Self {
+            fds: std::collections::HashMap::new(),
+        }
+    }
+
+    fn stdin(&self) -> Option<crate::mutex::Mutex<File>> {
+        self.fds.get(&0).map(crate::mutex::clone)
+    }
+
+    pub fn set_stdin<T: std::os::unix::io::IntoRawFd>(&mut self, stdin: T) {
+        if let Some(file) = self.fds.remove(&0) {
+            File::maybe_drop(file);
+        }
+        self.fds.insert(
+            0,
+            // Safety: we just acquired stdin via into_raw_fd, which acquires
+            // ownership of the fd, so we are now the sole owner
+            crate::mutex::new(unsafe { File::input(stdin.into_raw_fd()) }),
+        );
+    }
+
+    fn stdout(&self) -> Option<crate::mutex::Mutex<File>> {
+        self.fds.get(&1).map(crate::mutex::clone)
+    }
+
+    pub fn set_stdout<T: std::os::unix::io::IntoRawFd>(&mut self, stdout: T) {
+        if let Some(file) = self.fds.remove(&1) {
+            File::maybe_drop(file);
+        }
+        self.fds.insert(
+            1,
+            // Safety: we just acquired stdout via into_raw_fd, which acquires
+            // ownership of the fd, so we are now the sole owner
+            crate::mutex::new(unsafe { File::output(stdout.into_raw_fd()) }),
+        );
+    }
+
+    fn stderr(&self) -> Option<crate::mutex::Mutex<File>> {
+        self.fds.get(&2).map(crate::mutex::clone)
+    }
+
+    pub fn set_stderr<T: std::os::unix::io::IntoRawFd>(&mut self, stderr: T) {
+        if let Some(file) = self.fds.remove(&2) {
+            File::maybe_drop(file);
+        }
+        self.fds.insert(
+            2,
+            // Safety: we just acquired stderr via into_raw_fd, which acquires
+            // ownership of the fd, so we are now the sole owner
+            crate::mutex::new(unsafe { File::output(stderr.into_raw_fd()) }),
+        );
+    }
+
+    pub fn apply_redirects(&mut self, redirects: &[crate::parse::Redirect]) {
+        for redirect in redirects {
+            let to = match &redirect.to {
+                crate::parse::RedirectTarget::Fd(fd) => {
+                    crate::mutex::clone(&self.fds[fd])
+                }
+                crate::parse::RedirectTarget::File(path) => {
+                    let fd = redirect.dir.open(path).unwrap();
+                    match redirect.dir {
+                        crate::parse::Direction::In => {
+                            // Safety: we just opened fd, and nothing else has
+                            // or can use it
+                            crate::mutex::new(unsafe { File::input(fd) })
+                        }
+                        crate::parse::Direction::Out
+                        | crate::parse::Direction::Append => {
+                            // Safety: we just opened fd, and nothing else has
+                            // or can use it
+                            crate::mutex::new(unsafe { File::output(fd) })
+                        }
+                    }
+                }
+            };
+            self.fds.insert(redirect.from, to);
+        }
+    }
+
+    pub async fn read_line_stdin(&self) -> anyhow::Result<String> {
+        let mut buf = String::new();
+        if let Some(fh) = self.stdin() {
+            if let File::In(fh) = &mut *fh.lock_arc().await {
+                fh.read_line(&mut buf).await?;
+            }
+        }
+        if buf.ends_with('\n') {
+            buf.truncate(buf.len() - 1);
+        }
+        Ok(buf)
+    }
+
+    pub async fn write_stdout(&self, buf: &[u8]) -> anyhow::Result<()> {
+        if let Some(fh) = self.stdout() {
+            if let File::Out(fh) = &mut *fh.lock_arc().await {
+                Ok(fh.write_all(buf).await.map(|_| ())?)
+            } else {
+                Ok(())
+            }
+        } else {
+            Ok(())
+        }
+    }
+
+    pub async fn write_stderr(&self, buf: &[u8]) -> anyhow::Result<()> {
+        if let Some(fh) = self.stderr() {
+            if let File::Out(fh) = &mut *fh.lock_arc().await {
+                Ok(fh.write_all(buf).await.map(|_| ())?)
+            } else {
+                Ok(())
+            }
+        } else {
+            Ok(())
+        }
+    }
+
+    pub fn setup_command(mut self, cmd: &mut crate::runner::Command) {
+        if let Some(stdin) = self.fds.remove(&0) {
+            if let Some(stdin) = crate::mutex::unwrap(stdin) {
+                let stdin = stdin.into_raw_fd();
+                if stdin != 0 {
+                    // Safety: we just acquired stdin via into_raw_fd, which
+                    // acquires ownership of the fd, so we are now the sole
+                    // owner
+                    cmd.stdin(unsafe { std::fs::File::from_raw_fd(stdin) });
+                    self.fds.remove(&0);
+                }
+            }
+        }
+        if let Some(stdout) = self.fds.remove(&1) {
+            if let Some(stdout) = crate::mutex::unwrap(stdout) {
+                let stdout = stdout.into_raw_fd();
+                if stdout != 1 {
+                    // Safety: we just acquired stdout via into_raw_fd, which
+                    // acquires ownership of the fd, so we are now the sole
+                    // owner
+                    cmd.stdout(unsafe { std::fs::File::from_raw_fd(stdout) });
+                    self.fds.remove(&1);
+                }
+            }
+        }
+        if let Some(stderr) = self.fds.remove(&2) {
+            if let Some(stderr) = crate::mutex::unwrap(stderr) {
+                let stderr = stderr.into_raw_fd();
+                if stderr != 2 {
+                    // Safety: we just acquired stderr via into_raw_fd, which
+                    // acquires ownership of the fd, so we are now the sole
+                    // owner
+                    cmd.stderr(unsafe { std::fs::File::from_raw_fd(stderr) });
+                    self.fds.remove(&2);
+                }
+            }
+        }
+    }
+}
+
+impl Drop for Io {
+    fn drop(&mut self) {
+        for (_, file) in self.fds.drain() {
+            File::maybe_drop(file);
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum File {
+    In(async_std::io::BufReader<async_std::fs::File>),
+    Out(async_std::fs::File),
+}
+
+impl File {
+    // Safety: fd must not be owned by any other File object
+    pub unsafe fn input(fd: std::os::unix::io::RawFd) -> Self {
+        Self::In(async_std::io::BufReader::new(
+            async_std::fs::File::from_raw_fd(fd),
+        ))
+    }
+
+    // Safety: fd must not be owned by any other File object
+    pub unsafe fn output(fd: std::os::unix::io::RawFd) -> Self {
+        Self::Out(async_std::fs::File::from_raw_fd(fd))
+    }
+
+    fn maybe_drop(file: crate::mutex::Mutex<Self>) {
+        if let Some(file) = crate::mutex::unwrap(file) {
+            if file.as_raw_fd() <= 2 {
+                let _ = file.into_raw_fd();
+            }
+        }
+    }
+}
+
+impl std::os::unix::io::AsRawFd for File {
+    fn as_raw_fd(&self) -> std::os::unix::io::RawFd {
+        match self {
+            Self::In(fh) => fh.get_ref().as_raw_fd(),
+            Self::Out(fh) => fh.as_raw_fd(),
+        }
+    }
+}
+
+impl std::os::unix::io::IntoRawFd for File {
+    fn into_raw_fd(self) -> std::os::unix::io::RawFd {
+        match self {
+            Self::In(fh) => fh.into_inner().into_raw_fd(),
+            Self::Out(fh) => fh.into_raw_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::runner::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::runner::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)
+            }
+        })
+    }
+}