Initial commit for fern

src/shellenv/exec_ctx.rs

@@ -0,0 +1,116 @@
+use crate::prelude::*;
+
+bitflags! {
+	#[derive(Copy,Clone,Debug,PartialEq,PartialOrd)]
+	pub struct ExecFlags: u32 {
+		const NO_FORK = 0x00000001;
+	}
+}
+
+#[derive(Clone,Debug)]
+pub struct ExecCtx {
+	redirs: Vec<Redir>,
+	flags: ExecFlags,
+	io_masks: IoMasks,
+	saved_io: Option<SavedIo>
+}
+
+impl ExecCtx {
+	pub fn new() -> Self {
+		Self {
+			redirs: vec![],
+			flags: ExecFlags::empty(),
+			io_masks: IoMasks::new(),
+			saved_io: None
+		}
+	}
+	pub fn masks(&self) -> &IoMasks {
+		&self.io_masks
+	}
+	pub fn push_rdr(&mut self, redir: Redir) {
+		self.redirs.push(redir)
+	}
+	pub fn saved_io(&mut self) -> &mut Option<SavedIo> {
+		&mut self.saved_io
+	}
+	pub fn activate_rdrs(&mut self) -> ShResult<()> {
+		let mut redirs = CmdRedirs::new(core::mem::take(&mut self.redirs));
+		self.redirs = vec![];
+		redirs.activate()?;
+		Ok(())
+	}
+	pub fn flags(&self) -> ExecFlags {
+		self.flags
+	}
+	pub fn set_flag(&mut self, flag: ExecFlags) {
+		self.flags |= flag
+	}
+	pub fn unset_flag(&mut self, flag: ExecFlags) {
+		self.flags &= !flag
+	}
+}
+
+#[derive(Debug,Clone)]
+pub struct SavedIo {
+	pub stdin: RawFd,
+	pub stdout: RawFd,
+	pub stderr: RawFd
+}
+
+impl SavedIo {
+	pub fn save(stdin: RawFd, stdout: RawFd, stderr: RawFd) -> Self {
+		Self { stdin, stdout, stderr }
+	}
+}
+
+#[derive(Debug,Clone)]
+pub struct IoMask {
+	default: RawFd,
+	mask: Option<RawFd>
+}
+
+impl IoMask {
+	pub fn new(default: RawFd) -> Self {
+		Self { default, mask: None }
+	}
+	pub fn new_mask(&mut self, mask: RawFd) {
+		self.mask = Some(mask)
+	}
+	pub fn unmask(&mut self) {
+		self.mask = None
+	}
+	pub fn get_fd(&self) -> RawFd {
+		if let Some(fd) = self.mask {
+			fd
+		} else {
+			self.default
+		}
+	}
+}
+
+#[derive(Clone,Debug)]
+/// Necessary for when process file descriptors are permanently redirected using `exec`
+pub struct IoMasks {
+	stdin: IoMask,
+	stdout: IoMask,
+	stderr: IoMask
+}
+
+impl IoMasks {
+	pub fn new() -> Self {
+		Self {
+			stdin: IoMask::new(0),
+			stdout: IoMask::new(1),
+			stderr: IoMask::new(2),
+		}
+	}
+	pub fn stdin(&self) -> &IoMask {
+		&self.stdin
+	}
+	pub fn stdout(&self) -> &IoMask {
+		&self.stdout
+	}
+	pub fn stderr(&self) -> &IoMask {
+		&self.stderr
+	}
+}