use super::*;
use crate::{is_ascii_punctuation, utf8_char_len};
pub(super) fn parse_link_ref_def(input: &str) -> Option<(String, String, Option<String>, usize)> {
let bytes = input.as_bytes();
if bytes.is_empty() || bytes[0] != b'[' {
return None;
}
let mut i = 1;
let mut label = String::new();
let mut found_close = false;
while i < bytes.len() {
if bytes[i] == b']' {
found_close = true;
i += 1;
break;
}
if bytes[i] == b'[' {
return None;
}
if bytes[i] == b'\\' && i + 1 < bytes.len() {
label.push('\\');
let ch_len = utf8_char_len(bytes[i + 1]);
label
.push_str(std::str::from_utf8(&bytes[i + 1..i + 1 + ch_len]).unwrap_or("\u{FFFD}"));
i += 1 + ch_len;
} else {
let ch_len = utf8_char_len(bytes[i]);
label.push_str(std::str::from_utf8(&bytes[i..i + ch_len]).unwrap_or("\u{FFFD}"));
i += ch_len;
}
}
if !found_close || label.trim().is_empty() || label.len() > 999 {
return None;
}
if i >= bytes.len() || bytes[i] != b':' {
return None;
}
i += 1;
i = skip_spaces_and_optional_newline(bytes, i);
let (dest, dest_end) = parse_link_destination(bytes, i)?;
i = dest_end;
let before_title = i;
let title_start = skip_spaces_and_optional_newline(bytes, i);
let mut title = None;
if title_start < bytes.len()
&& title_start > before_title
&& let Some((t, t_end)) = parse_link_title(bytes, title_start)
{
let after = skip_line_spaces(bytes, t_end);
if after >= bytes.len() || bytes[after] == b'\n' {
title = Some(t);
let consumed = if after < bytes.len() {
after + 1
} else {
after
};
return Some((label, dest, title, consumed));
}
}
let after_dest = skip_line_spaces(bytes, before_title);
if after_dest < bytes.len() && bytes[after_dest] != b'\n' {
return None;
}
let consumed = if after_dest < bytes.len() {
after_dest + 1
} else {
after_dest
};
Some((label, dest, title, consumed))
}
pub(super) fn resolve_entities_and_escapes(s: &str) -> std::borrow::Cow<'_, str> {
let bytes = s.as_bytes();
if memchr::memchr2(b'\\', b'&', bytes).is_none() {
return std::borrow::Cow::Borrowed(s);
}
let mut out = String::with_capacity(s.len());
let mut i = 0;
while i < bytes.len() {
if bytes[i] == b'\\' && i + 1 < bytes.len() && is_ascii_punctuation(bytes[i + 1]) {
out.push(bytes[i + 1] as char);
i += 2;
} else if bytes[i] == b'&' {
if let Some(end) = resolve_entity_in_bytes(bytes, i, &mut out) {
i = end;
} else {
out.push('&');
i += 1;
}
} else {
let ch_len = utf8_char_len(bytes[i]);
out.push_str(&s[i..i + ch_len]);
i += ch_len;
}
}
std::borrow::Cow::Owned(out)
}
pub(super) fn resolve_entity_in_bytes(
bytes: &[u8],
start: usize,
out: &mut String,
) -> Option<usize> {
let mut i = start + 1;
if i >= bytes.len() {
return None;
}
if bytes[i] == b'#' {
i += 1;
let hex = i < bytes.len() && matches!(bytes[i], b'x' | b'X');
if hex {
i += 1;
}
let ns = i;
if hex {
while i < bytes.len() && bytes[i].is_ascii_hexdigit() {
i += 1;
}
} else {
while i < bytes.len() && bytes[i].is_ascii_digit() {
i += 1;
}
}
if i == ns || i - ns > 7 || i >= bytes.len() || bytes[i] != b';' {
return None;
}
let value = std::str::from_utf8(&bytes[ns..i]).ok()?;
i += 1;
if entities::resolve_numeric_ref_into(value, hex, out) {
Some(i)
} else {
None
}
} else {
let ns = i;
while i < bytes.len() && bytes[i].is_ascii_alphanumeric() {
i += 1;
}
if i == ns || i >= bytes.len() || bytes[i] != b';' {
return None;
}
let name = std::str::from_utf8(&bytes[ns..i]).ok()?;
i += 1;
if entities::lookup_entity_into(name, out) {
Some(i)
} else {
None
}
}
}
pub(super) fn skip_spaces_and_optional_newline(bytes: &[u8], mut i: usize) -> usize {
while i < bytes.len() && (bytes[i] == b' ' || bytes[i] == b'\t') {
i += 1;
}
if i < bytes.len() && bytes[i] == b'\n' {
i += 1;
while i < bytes.len() && (bytes[i] == b' ' || bytes[i] == b'\t') {
i += 1;
}
}
i
}
pub(super) fn skip_line_spaces(bytes: &[u8], mut i: usize) -> usize {
while i < bytes.len() && (bytes[i] == b' ' || bytes[i] == b'\t') {
i += 1;
}
i
}
pub(super) fn parse_link_destination(bytes: &[u8], start: usize) -> Option<(String, usize)> {
if start >= bytes.len() {
return None;
}
if bytes[start] == b'<' {
let mut i = start + 1;
let mut dest = String::new();
while i < bytes.len() {
if bytes[i] == b'>' {
return Some((dest, i + 1));
}
if bytes[i] == b'<' || bytes[i] == b'\n' {
return None;
}
if bytes[i] == b'\\' && i + 1 < bytes.len() {
let ch_len = utf8_char_len(bytes[i + 1]);
dest.push_str(
std::str::from_utf8(&bytes[i + 1..i + 1 + ch_len]).unwrap_or("\u{FFFD}"),
);
i += 1 + ch_len;
} else {
let ch_len = utf8_char_len(bytes[i]);
dest.push_str(std::str::from_utf8(&bytes[i..i + ch_len]).unwrap_or("\u{FFFD}"));
i += ch_len;
}
}
None
} else {
let mut i = start;
let mut paren_depth = 0i32;
let mut dest = String::new();
while i < bytes.len() {
let b = bytes[i];
if b <= b' ' {
break;
}
if b == b'(' {
paren_depth += 1;
if paren_depth > 32 {
return None;
}
dest.push('(');
i += 1;
} else if b == b')' {
if paren_depth == 0 {
break;
}
paren_depth -= 1;
dest.push(')');
i += 1;
} else if b == b'\\' && i + 1 < bytes.len() && is_ascii_punctuation(bytes[i + 1]) {
dest.push(bytes[i + 1] as char);
i += 2;
} else {
let ch_start = i;
i += utf8_char_len(b);
dest.push_str(std::str::from_utf8(&bytes[ch_start..i]).unwrap_or("\u{FFFD}"));
}
}
if paren_depth != 0 {
return None;
}
if dest.is_empty() && start < bytes.len() && bytes[start] != b'<' {
return None;
}
Some((dest, i))
}
}
pub(super) fn parse_link_title(bytes: &[u8], start: usize) -> Option<(String, usize)> {
if start >= bytes.len() {
return None;
}
let quote = bytes[start];
let close_quote = match quote {
b'"' => b'"',
b'\'' => b'\'',
b'(' => b')',
_ => return None,
};
let mut i = start + 1;
let mut title = String::new();
while i < bytes.len() {
if bytes[i] == close_quote {
return Some((title, i + 1));
}
if bytes[i] == b'(' && quote == b'(' {
return None;
}
if bytes[i] == b'\\' && i + 1 < bytes.len() && is_ascii_punctuation(bytes[i + 1]) {
title.push(bytes[i + 1] as char);
i += 2;
} else if bytes[i] == b'\n' {
title.push('\n');
i += 1;
} else {
let ch_start = i;
i += utf8_char_len(bytes[i]);
title.push_str(std::str::from_utf8(&bytes[ch_start..i]).unwrap_or("\u{FFFD}"));
}
}
None
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn atx_heading_basic() {
assert_eq!(parse_atx_heading("# foo"), Some((1, "foo")));
assert_eq!(parse_atx_heading("## foo"), Some((2, "foo")));
assert_eq!(parse_atx_heading("###### foo"), Some((6, "foo")));
assert_eq!(parse_atx_heading("####### foo"), None);
}
#[test]
fn atx_heading_closing() {
assert_eq!(parse_atx_heading("# foo ##"), Some((1, "foo")));
assert_eq!(parse_atx_heading("## foo ##"), Some((2, "foo")));
assert_eq!(parse_atx_heading("# foo #"), Some((1, "foo")));
}
#[test]
fn thematic_break_basic() {
assert!(is_thematic_break("***"));
assert!(is_thematic_break("---"));
assert!(is_thematic_break("___"));
assert!(is_thematic_break(" * * *"));
assert!(!is_thematic_break("--"));
}
#[test]
fn fence_start_basic() {
assert_eq!(parse_fence_start("```"), Some((b'`', 3, "")));
assert_eq!(parse_fence_start("```rust"), Some((b'`', 3, "rust")));
assert_eq!(parse_fence_start("~~~"), Some((b'~', 3, "")));
assert_eq!(parse_fence_start("``"), None);
}
#[test]
fn list_marker_basic() {
let m = parse_list_marker("- foo");
assert!(m.is_some());
let m = m.unwrap();
assert_eq!(m.kind, ListKind::Bullet(b'-'));
let m = parse_list_marker("1. foo");
assert!(m.is_some());
let m = m.unwrap();
assert_eq!(m.kind, ListKind::Ordered(b'.'));
assert_eq!(m.start_num, 1);
}
}