8168c7c44c
NB The custom method returned 0 on an input of 0, which is arguably incorrect: 0 is not a power of two; the method in `std` returns 1 in that case.
128 lines
4.0 KiB
Rust
128 lines
4.0 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Format string literals.
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use unicode_segmentation::UnicodeSegmentation;
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use regex::Regex;
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use Indent;
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use config::Config;
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use MIN_STRING;
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pub struct StringFormat<'a> {
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pub opener: &'a str,
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pub closer: &'a str,
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pub line_start: &'a str,
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pub line_end: &'a str,
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pub width: usize,
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pub offset: Indent,
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pub trim_end: bool,
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pub config: &'a Config,
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}
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// FIXME: simplify this!
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pub fn rewrite_string<'a>(orig: &str, fmt: &StringFormat<'a>) -> Option<String> {
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// Strip line breaks.
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let re = Regex::new(r"([^\\](\\\\)*)\\[\n\r][:space:]*").unwrap();
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let stripped_str = re.replace_all(orig, "$1");
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let graphemes = UnicodeSegmentation::graphemes(&*stripped_str, false).collect::<Vec<&str>>();
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let indent = fmt.offset.to_string(fmt.config);
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let punctuation = ":,;.";
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let mut cur_start = 0;
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let mut result = String::with_capacity(stripped_str.len()
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.checked_next_power_of_two()
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.unwrap_or(usize::max_value()));
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result.push_str(fmt.opener);
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let ender_length = fmt.line_end.len();
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// If we cannot put at least a single character per line, the rewrite won't
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// succeed.
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let max_chars = try_opt!(fmt.width.checked_sub(fmt.opener.len() + ender_length + 1)) + 1;
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loop {
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let mut cur_end = cur_start + max_chars;
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if cur_end >= graphemes.len() {
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let line = &graphemes[cur_start..].join("");
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result.push_str(line);
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break;
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}
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// Push cur_end left until we reach whitespace.
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while !graphemes[cur_end - 1].trim().is_empty() {
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cur_end -= 1;
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if cur_end - cur_start < MIN_STRING {
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cur_end = cur_start + max_chars;
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// Look for punctuation to break on.
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while (!punctuation.contains(graphemes[cur_end - 1])) && cur_end > 1 {
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cur_end -= 1;
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}
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// We can't break at whitespace or punctuation, fall back to splitting
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// anywhere that doesn't break an escape sequence.
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if cur_end < cur_start + MIN_STRING {
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cur_end = cur_start + max_chars;
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while graphemes[cur_end - 1] == "\\" && cur_end > 1 {
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cur_end -= 1;
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}
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}
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break;
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}
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}
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// Make sure there is no whitespace to the right of the break.
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while cur_end < stripped_str.len() && graphemes[cur_end].trim().is_empty() {
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cur_end += 1;
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}
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let raw_line = graphemes[cur_start..cur_end].join("");
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let line = if fmt.trim_end {
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raw_line.trim()
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} else {
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// FIXME: use as_str once it's stable.
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&*raw_line
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};
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result.push_str(line);
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result.push_str(fmt.line_end);
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result.push('\n');
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result.push_str(&indent);
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result.push_str(fmt.line_start);
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cur_start = cur_end;
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}
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result.push_str(fmt.closer);
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Some(result)
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}
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#[cfg(test)]
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mod test {
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use super::{StringFormat, rewrite_string};
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#[test]
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fn issue343() {
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let config = Default::default();
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let fmt = StringFormat {
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opener: "\"",
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closer: "\"",
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line_start: " ",
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line_end: "\\",
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width: 2,
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offset: ::Indent::empty(),
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trim_end: false,
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config: &config,
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};
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rewrite_string("eq_", &fmt);
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}
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}
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