Added 'read_key' builtin that allows widget scripts to handle input

src/builtin/read.rs

@@ -4,14 +4,10 @@ use nix::{
   libc::{STDIN_FILENO, STDOUT_FILENO},
   unistd::{isatty, read, write},
 };
+use yansi::Paint;
 
 use crate::{
-  getopt::{Opt, OptSpec, get_opts_from_tokens},
-  libsh::error::{ShErr, ShErrKind, ShResult, ShResultExt},
-  parse::{NdRule, Node, execute::prepare_argv},
-  procio::borrow_fd,
-  readline::term::RawModeGuard,
-  state::{self, VarFlags, VarKind, read_vars, write_vars},
+  expand::expand_keymap, getopt::{Opt, OptSpec, get_opts_from_tokens}, libsh::{error::{ShErr, ShErrKind, ShResult, ShResultExt}, sys::TTY_FILENO}, parse::{NdRule, Node, execute::prepare_argv}, procio::borrow_fd, readline::term::{KeyReader, PollReader, RawModeGuard}, state::{self, VarFlags, VarKind, read_vars, write_vars}
 };
 
 pub const READ_OPTS: [OptSpec; 7] = [
@@ -45,6 +41,21 @@ pub const READ_OPTS: [OptSpec; 7] = [
   }, // read until delimiter
 ];
 
+pub const READ_KEY_OPTS: [OptSpec;3] = [
+	OptSpec {
+		opt: Opt::Short('v'), // var name
+		takes_arg: true
+	},
+	OptSpec {
+		opt: Opt::Short('w'), // char whitelist
+		takes_arg: true
+	},
+	OptSpec {
+		opt: Opt::Short('b'), // char blacklist
+		takes_arg: true
+	}
+];
+
 bitflags! {
   pub struct ReadFlags: u32 {
     const NO_ESCAPES = 	0b000001;
@@ -245,3 +256,98 @@ pub fn get_read_flags(opts: Vec<Opt>) -> ShResult<ReadOpts> {
 
   Ok(read_opts)
 }
+
+pub struct ReadKeyOpts {
+	var_name: Option<String>,
+	char_whitelist: Option<String>,
+	char_blacklist: Option<String>
+}
+
+pub fn read_key(node: Node) -> ShResult<()> {
+	let blame = node.get_span().clone();
+	let NdRule::Command { argv, .. } = node.class else { unreachable!() };
+
+	if !isatty(*TTY_FILENO)? {
+		state::set_status(1);
+		return Ok(());
+	}
+
+	let (_, opts) = get_opts_from_tokens(argv, &READ_KEY_OPTS).blame(blame.clone())?;
+	let read_key_opts = get_read_key_opts(opts).blame(blame.clone())?;
+
+	let key = {
+		let _raw = crate::readline::term::raw_mode();
+		let mut buf = [0u8; 16];
+		match read(*TTY_FILENO, &mut buf) {
+			Ok(0) => {
+				state::set_status(1);
+				return Ok(());
+			}
+			Ok(n) => {
+				let mut reader = PollReader::new();
+				reader.feed_bytes(&buf[..n]);
+				let Some(key) = reader.read_key()? else {
+					state::set_status(1);
+					return Ok(());
+				};
+				key
+			},
+			Err(Errno::EINTR) => {
+				state::set_status(130);
+				return Ok(());
+			}
+			Err(e) => return Err(ShErr::simple(ShErrKind::ExecFail, format!("read_key: {e}"))),
+		}
+	};
+
+	let vim_seq = key.as_vim_seq()?;
+
+	if let Some(wl) = read_key_opts.char_whitelist {
+		let allowed = expand_keymap(&wl);
+		if !allowed.contains(&key) {
+			state::set_status(1);
+			return Ok(());
+		}
+	}
+
+	if let Some(bl) = read_key_opts.char_blacklist {
+		let disallowed = expand_keymap(&bl);
+		if disallowed.contains(&key) {
+			state::set_status(1);
+			return Ok(());
+		}
+	}
+
+	if let Some(var) = read_key_opts.var_name {
+		write_vars(|v| v.set_var(&var, VarKind::Str(vim_seq), VarFlags::NONE))?;
+	} else {
+		write(borrow_fd(STDOUT_FILENO), vim_seq.as_bytes())?;
+	}
+
+	state::set_status(0);
+	Ok(())
+}
+
+pub fn get_read_key_opts(opts: Vec<Opt>) -> ShResult<ReadKeyOpts> {
+	let mut read_key_opts = ReadKeyOpts {
+		var_name: None,
+		char_whitelist: None,
+		char_blacklist: None
+	};
+
+	for opt in opts {
+		match opt {
+			Opt::ShortWithArg('v', var_name) => read_key_opts.var_name = Some(var_name),
+			Opt::ShortWithArg('w', char_whitelist) => read_key_opts.char_whitelist = Some(char_whitelist),
+			Opt::ShortWithArg('b', char_blacklist) => read_key_opts.char_blacklist = Some(char_blacklist),
+			_ => {
+				return Err(ShErr::simple(
+					ShErrKind::ExecFail,
+					format!("read_key: Unexpected flag '{opt}'")
+				));
+			}
+		}
+	}
+
+	Ok(read_key_opts)
+}