oak-team/oak-gpui
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

display map: Fix left shift debug panic (#38656)

Browse Source 
Closes https://github.com/zed-industries/zed/issues/38558

The bug occurred because TabStopCursor chunk_position.1 is bounded
between 0 and 128. The fix for this was changing the bound to 0 and 127.

This also allowed me to simplify some of the tab stop cursor code to be
a bit faster (less branches and unbounded shifts).

Release Notes:

- N/A
This commit is contained in:
Anthony Eid
2025-10-29 09:34:33 -04:00
committed by GitHub
parent 6be029ff17
commit d44437d543
1 changed files with 8 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
crates/editor/src/display_map/tab_map.rs
+8 -8
View File
@@ -1440,7 +1440,7 @@ where
self.current_chunk.as_ref().and_then(|(chunk, idx)| {
let mut idx = *idx;
let mut diff = 0;
while idx > 0 && chunk.chars & (1 << idx) == 0 {
while idx > 0 && chunk.chars & (1u128.unbounded_shl(idx)) == 0 {
idx -= 1;
diff += 1;
}
@@ -1460,7 +1460,7 @@ where
fn is_char_boundary(&self) -> bool {
self.current_chunk
.as_ref()
.is_some_and(|(chunk, idx)| (chunk.chars & (1 << *idx.min(&127))) != 0)
.is_some_and(|(chunk, idx)| (chunk.chars & 1u128.unbounded_shl(*idx)) != 0)
}
/// distance: length to move forward while searching for the next tab stop
@@ -1483,18 +1483,20 @@ where
self.byte_offset += overshoot;
self.char_offset += get_char_offset(
chunk_position..(chunk_position + overshoot).saturating_sub(1).min(127),
chunk_position..(chunk_position + overshoot).saturating_sub(1),
chunk.chars,
);
self.current_chunk = Some((chunk, chunk_position + overshoot));
if chunk_position + overshoot < 128 {
self.current_chunk = Some((chunk, chunk_position + overshoot));
}
return None;
}
self.byte_offset += chunk_distance;
self.char_offset += get_char_offset(
chunk_position..(chunk_position + chunk_distance).saturating_sub(1).min(127),
chunk_position..(chunk_position + chunk_distance).saturating_sub(1),
chunk.chars,
);
distance_traversed += chunk_distance;
@@ -1546,8 +1548,6 @@ where
#[inline(always)]
fn get_char_offset(range: Range<u32>, bit_map: u128) -> u32 {
// This edge case can happen when we're at chunk position 128
if range.start == range.end {
return if (1u128 << range.start) & bit_map == 0 {
0
@@ -1555,7 +1555,7 @@ fn get_char_offset(range: Range<u32>, bit_map: u128) -> u32 {
1
};
}
let end_shift: u128 = 127u128 - range.end.min(127) as u128;
let end_shift: u128 = 127u128 - range.end as u128;
let mut bit_mask = (u128::MAX >> range.start) << range.start;
bit_mask = (bit_mask << end_shift) >> end_shift;
let bit_map = bit_map & bit_mask;