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"mod three rule" fix #262

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Merged
kivikakk merged 2 commits into from
Jan 1, 2023
Merged

"mod three rule" fix #262

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7d08eeb
inlines: "mod three rule" fix from https://github.com/commonmark/cmar…
kivikakk Jan 1, 2023
a3fac83
inlines: adapt openers logic here per cmark upstream
kivikakk Jan 1, 2023
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44 changes: 21 additions & 23 deletions src/parser/inlines.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -238,19 +238,7 @@ impl<'a, 'r, 'o, 'd, 'i, 'c, 'subj> Subject<'a, 'r, 'o, 'd, 'i, 'c, 'subj> {
// This array is an important optimization that prevents searching down
// the stack for openers we've previously searched for and know don't
// exist, preventing exponential blowup on pathological cases.
let mut openers_bottom: [[Option<&'d Delimiter<'a, 'd>>; 128]; 3] = [[None; 128]; 3];
for i in &mut openers_bottom {
i['*' as usize] = stack_bottom;
i['_' as usize] = stack_bottom;
i['\'' as usize] = stack_bottom;
i['"' as usize] = stack_bottom;
if self.options.extension.strikethrough {
i['~' as usize] = stack_bottom;
}
if self.options.extension.superscript {
i['^' as usize] = stack_bottom;
}
}
let mut openers_bottom: [Option<&'d Delimiter<'a, 'd>>; 11] = [stack_bottom; 11];

// This is traversing the stack from the top to the bottom, setting `closer` to
// the delimiter directly above `stack_bottom`. In the case where we are processing
Expand All @@ -268,6 +256,20 @@ impl<'a, 'r, 'o, 'd, 'i, 'c, 'subj> Subject<'a, 'r, 'o, 'd, 'i, 'c, 'subj> {

let mut opener = closer.unwrap().prev.get();
let mut opener_found = false;
let mut mod_three_rule_invoked = false;

let ix = match closer.unwrap().delim_char {
b'~' => 0,
b'^' => 1,
b'"' => 2,
b'\'' => 3,
b'_' => 4,
b'*' => {
5 + (if closer.unwrap().can_open { 3 } else { 0 })
+ (closer.unwrap().length % 3)
}
_ => unreachable!(),
};

// Here's where we find the opener by searching down the stack,
// looking for matching delims with the `can_open` flag.
Expand All @@ -280,13 +282,7 @@ impl<'a, 'r, 'o, 'd, 'i, 'c, 'subj> Subject<'a, 'r, 'o, 'd, 'i, 'c, 'subj> {
// This search short-circuits for openers we've previously
// failed to find, avoiding repeatedly rescanning the bottom of
// the stack, using the openers_bottom array.
while opener.is_some()
&& !Self::del_ref_eq(
opener,
openers_bottom[closer.unwrap().length % 3]
[closer.unwrap().delim_char as usize],
)
{
while opener.is_some() && !Self::del_ref_eq(opener, openers_bottom[ix]) {
if opener.unwrap().can_open
&& opener.unwrap().delim_char == closer.unwrap().delim_char
{
Expand All @@ -306,6 +302,8 @@ impl<'a, 'r, 'o, 'd, 'i, 'c, 'subj> Subject<'a, 'r, 'o, 'd, 'i, 'c, 'subj> {
if !odd_match {
opener_found = true;
break;
} else {
mod_three_rule_invoked = true;
}
}
opener = opener.unwrap().prev.get();
Expand Down Expand Up @@ -389,9 +387,9 @@ impl<'a, 'r, 'o, 'd, 'i, 'c, 'subj> Subject<'a, 'r, 'o, 'd, 'i, 'c, 'subj> {
// so that the `opener` search can avoid looking for this
// same opener at the bottom of the stack later.
if !opener_found {
let ix = old_closer.unwrap().length % 3;
openers_bottom[ix][old_closer.unwrap().delim_char as usize] =
old_closer.unwrap().prev.get();
if !mod_three_rule_invoked {
openers_bottom[ix] = old_closer.unwrap().prev.get();
}

// Now that we've failed the `opener` search starting from
// `old_closer`, future opener searches will be searching it
Expand Down