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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Format string literals.
use unicode_segmentation::UnicodeSegmentation;
use regex::Regex;
use Indent;
use config::Config;
use utils::round_up_to_power_of_two;
use MIN_STRING;
pub struct StringFormat<'a> {
pub opener: &'a str,
pub closer: &'a str,
pub line_start: &'a str,
pub line_end: &'a str,
pub width: usize,
pub offset: Indent,
pub trim_end: bool,
pub config: &'a Config,
}
// TODO: simplify this!
pub fn rewrite_string<'a>(s: &str, fmt: &StringFormat<'a>) -> Option<String> {
// TODO if lo.col > IDEAL - 10, start a new line (need cur indent for that)
// Strip line breaks.
let re = Regex::new(r"(\\[:space:]+)").unwrap();
let stripped_str = re.replace_all(s, "");
let graphemes = UnicodeSegmentation::graphemes(&*stripped_str, false).collect::<Vec<&str>>();
let indent = fmt.offset.to_string(fmt.config);
let punctuation = ":,;.";
let mut cur_start = 0;
let mut result = String::with_capacity(round_up_to_power_of_two(s.len()));
result.push_str(fmt.opener);
let ender_length = fmt.line_end.len();
// If we cannot put at least a single character per line, the rewrite won't
// succeed.
let max_chars = try_opt!(fmt.width.checked_sub(fmt.opener.len() + ender_length + 1)) + 1;
loop {
let mut cur_end = cur_start + max_chars;
if cur_end >= graphemes.len() {
let line = &graphemes[cur_start..].join("");
result.push_str(line);
break;
}
// Push cur_end left until we reach whitespace.
while !graphemes[cur_end - 1].trim().is_empty() {
cur_end -= 1;
if cur_end - cur_start < MIN_STRING {
cur_end = cur_start + max_chars;
// Look for punctuation to break on.
while (!punctuation.contains(graphemes[cur_end - 1])) && cur_end > 1 {
cur_end -= 1;
}
// We can't break at whitespace or punctuation, fall back to splitting
// anywhere that doesn't break an escape sequence.
if cur_end < cur_start + MIN_STRING {
cur_end = cur_start + max_chars;
while graphemes[cur_end - 1] == "\\" && cur_end > 1 {
cur_end -= 1;
}
}
break;
}
}
// Make sure there is no whitespace to the right of the break.
while cur_end < s.len() && graphemes[cur_end].trim().is_empty() {
cur_end += 1;
}
let raw_line = graphemes[cur_start..cur_end].join("");
let line = if fmt.trim_end {
raw_line.trim()
} else {
// TODO: use as_str once it's stable.
&*raw_line
};
result.push_str(line);
result.push_str(fmt.line_end);
result.push('\n');
result.push_str(&indent);
result.push_str(fmt.line_start);
cur_start = cur_end;
}
result.push_str(fmt.closer);
Some(result)
}
#[cfg(test)]
mod test {
use super::{StringFormat, rewrite_string};
#[test]
fn issue343() {
let config = Default::default();
let fmt = StringFormat {
opener: "\"",
closer: "\"",
line_start: " ",
line_end: "\\",
width: 2,
offset: ::Indent::empty(),
trim_end: false,
config: &config,
};
rewrite_string("eq_", &fmt);
}
}
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