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use crate::{Cow, Shard};
#[derive(Clone, Copy, Debug)]
pub struct SyntaxError;
pub struct ShellwordSplitter<'a> {
input: &'a str,
}
impl<'a> ShellwordSplitter<'a> {
pub fn new(input: &'a str) -> Self {
Self { input }
}
fn skip_whitespace(&mut self) {
let mut it = self.input.char_indices();
self.input = loop {
break match it.next() {
None => "",
Some((pos, x)) if !x.is_whitespace() => &self.input[pos..],
_ => continue,
};
};
}
}
fn ch_is_quote(ch: char) -> bool {
matches!(ch, '"' | '\'')
}
impl<'a> Iterator for ShellwordSplitter<'a> {
type Item = Result<Cow<'a, str>, SyntaxError>;
fn next(&mut self) -> Option<Self::Item> {
self.skip_whitespace();
let mut it = self.input.char_indices();
let mut quotec = None;
let mut ret = Shard::<'a>::new(self.input);
while let Some((cpos, cx)) = it.next() {
if cx == '\\' {
// escape works the same, no matter if inside or outside of quotes
let x = match it.next() {
Some(i) => i.1,
None => {
self.input = "";
return Some(Err(SyntaxError));
}
};
ret.push_owned(match x {
'n' => '\n',
't' => '\t',
'r' => '\r',
_ if quotec.is_some() && x.is_whitespace() => continue,
_ => x,
});
continue;
}
if quotec.is_none() {
if ch_is_quote(cx) {
// start of quotation
quotec = Some(cx);
// allow the algo to reuse simple, quoted args
ret.skip(1);
continue;
} else if cx.is_whitespace() {
// argument separator, this will never happen on the first iteration
self.input = &self.input[cpos..];
return ret.finish_cvg().map(Ok);
}
} else if Some(cx) == quotec {
// end of quotation
quotec = None;
match it.next() {
Some((npos, nx)) if nx.is_whitespace() => {
// simple case: the ending quote is followed by an separator
// we can thus skip the whitespace and return our item
self.input = &self.input[npos..];
return ret.finish_cvg().map(Ok);
}
Some((_, nx)) if ch_is_quote(nx) => {
// medium case: the ending quote if directly followed by another quote
// thus, remain in quote mode
quotec = Some(nx);
}
Some((_, nx)) => {
// complex case: the ending quote is followed by more data which
// belongs to the same argument
ret.push_owned(nx);
}
None => {
// simple case: the ending quote is followed by EOF
self.input = "";
return ret.finish_cvg().map(Ok);
}
}
continue;
}
ret.push(cx);
}
self.input = "";
if quotec.is_some() {
return Some(Err(SyntaxError));
}
ret.finish_cvg().map(Ok)
}
}
#[cfg(test)]
mod tests {
use alloc::{string::String, vec::Vec};
use proptest::prelude::*;
/// split_shellwords tests were taken from
/// https://docs.rs/shellwords/1.1.0/src/shellwords/lib.rs.html
/// License: MIT
fn split(x: &str) -> Result<Vec<String>, super::SyntaxError> {
super::ShellwordSplitter::new(x)
.map(|i| i.map(super::Cow::into_owned))
.collect()
}
#[test]
fn nothing_special() {
assert_eq!(split("a b c d").unwrap(), ["a", "b", "c", "d"]);
}
#[test]
fn quoted_strings() {
assert_eq!(split("a \"b b\" a").unwrap(), ["a", "b b", "a"]);
}
#[test]
fn escaped_double_quotes() {
assert_eq!(split("a \"\\\"b\\\" c\" d").unwrap(), ["a", "\"b\" c", "d"]);
}
#[test]
fn escaped_single_quotes() {
assert_eq!(split("a \"'b' c\" d").unwrap(), ["a", "'b' c", "d"]);
}
#[test]
fn escaped_spaces() {
assert_eq!(split("a b\\ c d").unwrap(), ["a", "b c", "d"]);
}
#[test]
fn start_with_qspaces() {
assert_eq!(split("\" \" b c").unwrap(), [" ", "b", "c"]);
}
#[test]
fn bad_double_quotes() {
split("a \"b c d e").unwrap_err();
}
#[test]
fn bad_single_quotes() {
split("a 'b c d e").unwrap_err();
}
#[test]
fn bad_quotes() {
split("one '\"\"\"").unwrap_err();
}
#[test]
fn trailing_whitespace() {
assert_eq!(split("a b c d ").unwrap(), ["a", "b", "c", "d"]);
}
proptest! {
#[test]
fn doesnt_crash(s in "\\PC*") {
let _: Vec<_> = super::ShellwordSplitter::new(&s).collect();
}
}
}