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use regex::Regex;
use unicode_segmentation::UnicodeSegmentation;
#[derive(Debug, Default, PartialEq)]
pub struct FormatStringPlaceholderData<'a> {
pub prefix: &'a str,
pub placeholder: Option<&'a str>,
pub alignment_spec: Option<&'a str>,
pub width: Option<usize>,
pub suffix: &'a str,
pub prefix_len: usize,
pub suffix_len: usize,
}
impl<'a> FormatStringPlaceholderData<'a> {
pub fn width(&self, hunk_max_line_number_width: usize) -> (usize, usize) {
// Only if Some(placeholder) is present will there be a number formatted
// by this placeholder, if not width is also None.
(
self.prefix_len
+ std::cmp::max(
self.placeholder.map_or(0, |_| hunk_max_line_number_width),
self.width.unwrap_or(0),
),
self.suffix_len,
)
}
}
pub type FormatStringData<'a> = Vec<FormatStringPlaceholderData<'a>>;
pub fn make_placeholder_regex(labels: &[&str]) -> Regex {
Regex::new(&format!(
r"(?x)
\{{
({}) # 1: Placeholder labels
(?: # Start optional format spec (non-capturing)
: # Literal colon
(?: # Start optional fill/alignment spec (non-capturing)
([^<^>])? # 2: Optional fill character (ignored)
([<^>]) # 3: Alignment spec
)? #
(\d+) # 4: Width
)? #
\}}
",
labels.join("|")
))
.unwrap()
}
pub fn parse_line_number_format<'a>(
format_string: &'a str,
placeholder_regex: &Regex,
) -> FormatStringData<'a> {
let mut format_data = Vec::new();
let mut offset = 0;
for captures in placeholder_regex.captures_iter(format_string) {
let _match = captures.get(0).unwrap();
let prefix = &format_string[offset.._match.start()];
let suffix = &format_string[_match.end()..];
format_data.push(FormatStringPlaceholderData {
prefix,
placeholder: captures.get(1).map(|m| m.as_str()),
alignment_spec: captures.get(3).map(|m| m.as_str()),
width: captures.get(4).map(|m| {
m.as_str()
.parse()
.unwrap_or_else(|_| panic!("Invalid width in format string: {}", format_string))
}),
suffix,
prefix_len: prefix.graphemes(true).count(),
suffix_len: suffix.graphemes(true).count(),
});
offset = _match.end();
}
if offset == 0 {
// No placeholders
format_data.push(FormatStringPlaceholderData {
prefix: &format_string[..0],
placeholder: None,
alignment_spec: None,
width: None,
suffix: &format_string[0..],
prefix_len: 0,
suffix_len: format_string.graphemes(true).count(),
})
}
format_data
}
pub fn pad(s: &str, width: usize, alignment: &str) -> String {
match alignment {
"<" => format!("{0:<1$}", s, width),
"^" => format!("{0:^1$}", s, width),
">" => format!("{0:>1$}", s, width),
_ => unreachable!(),
}
}
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