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<!-- Please describe your changes on the following line: --> Hi there, This PR replaces `match` statements by `if let` when possible. Thanks for reviewing --- <!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: --> - [X] `./mach build -d` does not report any errors - [X] `./mach test-tidy` does not report any errors - [X] These changes fix #14788 <!-- Either: --> - [ ] There are tests for these changes OR - [X] These changes do not require tests because this PR is a code cleanup patch. <!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. --> Source-Repo: https://github.com/servo/servo Source-Revision: d967d89fc081ae0f48850f3e29e4a9848bd837c7
158 lines
4.4 KiB
Rust
158 lines
4.4 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! String utils for attributes and similar stuff.
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#![deny(missing_docs)]
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use num_traits::ToPrimitive;
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use std::ascii::AsciiExt;
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use std::borrow::Cow;
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use std::convert::AsRef;
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use std::iter::{Filter, Peekable};
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use std::str::Split;
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/// A static slice of characters.
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pub type StaticCharVec = &'static [char];
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/// A static slice of `str`s.
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pub type StaticStringVec = &'static [&'static str];
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/// A "space character" according to:
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///
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/// https://html.spec.whatwg.org/multipage/#space-character
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pub static HTML_SPACE_CHARACTERS: StaticCharVec = &[
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'\u{0020}',
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'\u{0009}',
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'\u{000a}',
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'\u{000c}',
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'\u{000d}',
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];
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/// Whether a character is a HTML whitespace character.
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#[inline]
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pub fn char_is_whitespace(c: char) -> bool {
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HTML_SPACE_CHARACTERS.contains(&c)
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}
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/// Whether all the string is HTML whitespace.
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#[inline]
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pub fn is_whitespace(s: &str) -> bool {
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s.chars().all(char_is_whitespace)
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}
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#[inline]
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fn not_empty(&split: &&str) -> bool { !split.is_empty() }
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/// Split a string on HTML whitespace.
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#[inline]
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pub fn split_html_space_chars<'a>(s: &'a str) ->
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Filter<Split<'a, StaticCharVec>, fn(&&str) -> bool> {
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s.split(HTML_SPACE_CHARACTERS).filter(not_empty as fn(&&str) -> bool)
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}
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/// Split a string on commas.
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#[inline]
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pub fn split_commas<'a>(s: &'a str) -> Filter<Split<'a, char>, fn(&&str) -> bool> {
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s.split(',').filter(not_empty as fn(&&str) -> bool)
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}
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fn is_ascii_digit(c: &char) -> bool {
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match *c {
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'0'...'9' => true,
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_ => false,
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}
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}
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fn is_decimal_point(c: char) -> bool {
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c == '.'
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}
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fn is_exponent_char(c: char) -> bool {
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match c {
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'e' | 'E' => true,
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_ => false,
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}
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}
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/// Read a set of ascii digits and read them into a number.
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pub fn read_numbers<I: Iterator<Item=char>>(mut iter: Peekable<I>) -> (Option<i64>, usize) {
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match iter.peek() {
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Some(c) if is_ascii_digit(c) => (),
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_ => return (None, 0),
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}
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iter.take_while(is_ascii_digit).map(|d| {
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d as i64 - '0' as i64
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}).fold((Some(0i64), 0), |accumulator, d| {
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let digits = accumulator.0.and_then(|accumulator| {
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accumulator.checked_mul(10)
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}).and_then(|accumulator| {
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accumulator.checked_add(d)
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});
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(digits, accumulator.1 + 1)
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})
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}
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/// Read a decimal fraction.
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pub fn read_fraction<I: Iterator<Item=char>>(mut iter: Peekable<I>,
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mut divisor: f64,
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value: f64) -> (f64, usize) {
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match iter.peek() {
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Some(c) if is_decimal_point(*c) => (),
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_ => return (value, 0),
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}
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iter.next();
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iter.take_while(is_ascii_digit).map(|d|
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d as i64 - '0' as i64
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).fold((value, 1), |accumulator, d| {
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divisor *= 10f64;
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(accumulator.0 + d as f64 / divisor, accumulator.1 + 1)
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})
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}
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/// Reads an exponent from an iterator over chars, for example `e100`.
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pub fn read_exponent<I: Iterator<Item=char>>(mut iter: Peekable<I>) -> Option<i32> {
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match iter.peek() {
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Some(c) if is_exponent_char(*c) => (),
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_ => return None,
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}
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iter.next();
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match iter.peek() {
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None => None,
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Some(&'-') => {
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iter.next();
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read_numbers(iter).0.map(|exp| -exp.to_i32().unwrap_or(0))
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}
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Some(&'+') => {
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iter.next();
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read_numbers(iter).0.map(|exp| exp.to_i32().unwrap_or(0))
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}
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Some(_) => read_numbers(iter).0.map(|exp| exp.to_i32().unwrap_or(0))
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}
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}
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/// Join a set of strings with a given delimiter `join`.
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pub fn str_join<I, T>(strs: I, join: &str) -> String
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where I: IntoIterator<Item=T>,
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T: AsRef<str>,
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{
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strs.into_iter().enumerate().fold(String::new(), |mut acc, (i, s)| {
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if i > 0 { acc.push_str(join); }
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acc.push_str(s.as_ref());
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acc
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})
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}
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/// Like AsciiExt::to_ascii_lowercase, but avoids allocating when the input is already lower-case.
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pub fn cow_into_ascii_lowercase<'a, S: Into<Cow<'a, str>>>(s: S) -> Cow<'a, str> {
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let mut cow = s.into();
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if let Some(first_uppercase) = cow.bytes().position(|byte| byte >= b'A' && byte <= b'Z') {
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cow.to_mut()[first_uppercase..].make_ascii_lowercase();
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}
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cow
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}
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