265 lines
8.6 KiB
Rust

use super::strings::prev_char_boundary;
pub fn sep_name_and_value_indices(
indices: &mut Vec<u32>,
name_len: u32,
) -> (Vec<u32>, Vec<u32>, bool, bool) {
let mut name_indices = Vec::new();
let mut value_indices = Vec::new();
let mut should_add_name_indices = false;
let mut should_add_value_indices = false;
for i in indices.drain(..) {
if i < name_len {
name_indices.push(i);
should_add_name_indices = true;
} else {
value_indices.push(i - name_len);
should_add_value_indices = true;
}
}
name_indices.sort_unstable();
name_indices.dedup();
value_indices.sort_unstable();
value_indices.dedup();
(
name_indices,
value_indices,
should_add_name_indices,
should_add_value_indices,
)
}
const ELLIPSIS: &str = "";
const ELLIPSIS_CHAR_WIDTH_U16: u16 = 1;
const ELLIPSIS_BYTE_LEN_U32: u32 = 3;
/// Truncate a string to fit within a certain width, while keeping track of the
/// indices of the highlighted characters.
///
/// This will either truncate from the start or the end of the string, depending
/// on where the highlighted characters are.
///
/// NOTE: This function assumes that the highlighted ranges are sorted and non-overlapping.
pub fn truncate_highlighted_string<'a>(
s: &'a str,
highlighted_ranges: &'a [(u32, u32)],
max_width: u16,
) -> (String, Vec<(u32, u32)>) {
let (byte_positions, chars) =
s.char_indices().unzip::<_, _, Vec<_>, Vec<_>>();
if chars.len() <= max_width as usize {
return (s.to_string(), highlighted_ranges.to_vec());
}
let max_byte_index = byte_positions[usize::from(max_width)];
let last_highlighted_byte_index =
highlighted_ranges.last().unwrap_or(&(0, 0)).1 as usize;
// if the string isn't highlighted, or all highlighted characters are within the max byte index,
// simply truncate it from the right and add an ellipsis
if highlighted_ranges.is_empty()
// is the last highlighted byte index within the max byte index?
|| last_highlighted_byte_index < max_byte_index - 1
{
return (
s.chars()
.take(
max_width.saturating_sub(ELLIPSIS_CHAR_WIDTH_U16) as usize
)
.collect::<String>()
+ ELLIPSIS,
highlighted_ranges.to_vec(),
);
}
// otherwise, if the last highlighted byte index is within the last "max width" bytes of the
// string, truncate it from the left and add an ellipsis at the beginning
let start_offset = (chars.len() + 1).saturating_sub(max_width as usize);
let byte_offset = byte_positions[start_offset];
if last_highlighted_byte_index > byte_offset {
return (
ELLIPSIS.to_string()
+ &s.chars().skip(start_offset).collect::<String>(),
highlighted_ranges
.iter()
.map(|(start, end)| {
(
start.saturating_sub(
u32::try_from(byte_offset).unwrap(),
) + ELLIPSIS_BYTE_LEN_U32,
end.saturating_sub(
u32::try_from(byte_offset).unwrap(),
) + ELLIPSIS_BYTE_LEN_U32,
)
})
.filter(|(start, end)| start != end)
.collect(),
);
}
// otherwise, try to put the last highlighted character towards the end of the truncated string and
// truncate from both sides to fit the max width
let byte_offset =
// note that we're using `max_width` here as a rough estimate to avoid more complex calculations
// and then finding the closest character boundary
prev_char_boundary(s, last_highlighted_byte_index.saturating_sub(max_width.saturating_sub(2) as usize));
(
ELLIPSIS.to_string()
+ &s[byte_offset..]
.chars()
.take(max_width.saturating_sub(2 * ELLIPSIS_CHAR_WIDTH_U16)
as usize)
.collect::<String>()
+ ELLIPSIS,
highlighted_ranges
.iter()
.map(|(start, end)| {
(
start.saturating_sub(u32::try_from(byte_offset).unwrap())
+ ELLIPSIS_BYTE_LEN_U32,
end.saturating_sub(u32::try_from(byte_offset).unwrap())
+ ELLIPSIS_BYTE_LEN_U32,
)
})
.filter(|(start, end)| start != end)
.collect(),
)
}
#[cfg(test)]
mod tests {
#[test]
/// string: themes/solarized-light.toml
/// highlights: ----
/// max width: ---------------------------
/// result: themes/solarized-light.toml
/// expected: ----
fn test_truncate_hightlighted_string_no_op() {
let s = "themes/solarized-light.toml";
let highlighted_ranges = vec![(23, 27)];
let max_width = 27;
let (truncated, ranges) = super::truncate_highlighted_string(
s,
&highlighted_ranges,
max_width,
);
assert_eq!(truncated, s);
assert_eq!(ranges, highlighted_ranges);
}
#[test]
/// string: hello world
/// highlights:
/// max width: -----
/// result: hell…
fn test_truncate_hightlighted_string_no_highlight() {
let s = "hello world";
let highlighted_ranges = vec![];
let max_width = 5;
let (truncated, ranges) = super::truncate_highlighted_string(
s,
&highlighted_ranges,
max_width,
);
assert_eq!(truncated, "hell…");
assert_eq!(ranges, highlighted_ranges);
}
#[test]
/// string: hello world
/// highlights: -----
/// max width: ----------
/// result: hello wor…
fn test_truncate_hightlighted_string_highlights_fit_left() {
let s = "hello world";
let highlighted_ranges = vec![(0, 5)];
let max_width = 10;
let (truncated, ranges) = super::truncate_highlighted_string(
s,
&highlighted_ranges,
max_width,
);
assert_eq!(truncated, "hello wor…");
assert_eq!(ranges, highlighted_ranges);
}
#[test]
/// string: hello world
/// highlights: -- ---- -
/// max width: ------
/// ------
/// result: …world
fn test_truncate_highlighted_string_highlights_right() {
let s = "hello world";
let highlighted_ranges = vec![(0, 2), (4, 8), (10, 11)];
let max_width = 6;
let (truncated, ranges) = super::truncate_highlighted_string(
s,
&highlighted_ranges,
max_width,
);
assert_eq!(truncated, "…world");
// the ellipsis is 3 bytes long
assert_eq!(ranges, vec![(3, 5), (7, 8)]);
}
#[test]
/// string: themes/solarized-light.toml
/// highlights: ----
/// max width: --------------------------
/// result: …emes/solarized-light.toml
/// expected: ----
fn test_truncate_highlighted_string_truncate_left() {
let s = "themes/solarized-light.toml";
let highlighted_ranges = vec![(23, 27)];
let max_width = 26;
let (truncated, ranges) = super::truncate_highlighted_string(
s,
&highlighted_ranges,
max_width,
);
assert_eq!(truncated, "…emes/solarized-light.toml");
assert_eq!(ranges, vec![(24, 28)]);
}
#[test]
fn ellipsis_len() {
assert_eq!(
super::ELLIPSIS.chars().count(),
super::ELLIPSIS_CHAR_WIDTH_U16 as usize
);
assert_eq!(
super::ELLIPSIS.len(),
super::ELLIPSIS_BYTE_LEN_U32 as usize
);
}
#[test]
/// string: themes/solarized-light.toml
/// highlights: ---
/// max width: ------- 7
/// result: …lariz…
/// expected: ---
fn test_truncate_highlighted_string_truncate_middle() {
let s = "themes/solarized-light.toml";
let highlighted_ranges = vec![(11, 14)];
let max_width = 7;
let (truncated, ranges) = super::truncate_highlighted_string(
s,
&highlighted_ranges,
max_width,
);
assert_eq!(truncated, "…lariz…");
assert_eq!(ranges, vec![(5, 8)]);
}
}