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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
//! String utils for attributes and similar stuff.
#![deny(missing_docs)]
use num_traits::ToPrimitive;
use std::borrow::Cow;
use std::convert::AsRef;
use std::fmt::{self, Write};
use std::iter::{Filter, Peekable};
use std::str::Split;
/// A static slice of characters.
pub type StaticCharVec = &'static [char];
/// A static slice of `str`s.
pub type StaticStringVec = &'static [&'static str];
/// A "space character" according to:
///
pub static HTML_SPACE_CHARACTERS: StaticCharVec =
&['\u{0020}', '\u{0009}', '\u{000a}', '\u{000c}', '\u{000d}'];
/// Whether a character is a HTML whitespace character.
#[inline]
pub fn char_is_whitespace(c: char) -> bool {
HTML_SPACE_CHARACTERS.contains(&c)
}
/// Whether all the string is HTML whitespace.
#[inline]
pub fn is_whitespace(s: &str) -> bool {
s.chars().all(char_is_whitespace)
}
#[inline]
fn not_empty(&split: &&str) -> bool {
!split.is_empty()
}
/// Split a string on HTML whitespace.
#[inline]
pub fn split_html_space_chars<'a>(
s: &'a str,
) -> Filter<Split<'a, StaticCharVec>, fn(&&str) -> bool> {
s.split(HTML_SPACE_CHARACTERS)
.filter(not_empty as fn(&&str) -> bool)
}
/// Split a string on commas.
#[inline]
pub fn split_commas<'a>(s: &'a str) -> Filter<Split<'a, char>, fn(&&str) -> bool> {
s.split(',').filter(not_empty as fn(&&str) -> bool)
}
/// Character is ascii digit
pub fn is_ascii_digit(c: &char) -> bool {
match *c {
'0'..='9' => true,
_ => false,
}
}
fn is_decimal_point(c: char) -> bool {
c == '.'
}
fn is_exponent_char(c: char) -> bool {
match c {
'e' | 'E' => true,
_ => false,
}
}
/// Read a set of ascii digits and read them into a number.
pub fn read_numbers<I: Iterator<Item = char>>(mut iter: Peekable<I>) -> (Option<i64>, usize) {
match iter.peek() {
Some(c) if is_ascii_digit(c) => (),
_ => return (None, 0),
}
iter.take_while(is_ascii_digit)
.map(|d| d as i64 - '0' as i64)
.fold((Some(0i64), 0), |accumulator, d| {
let digits = accumulator
.0
.and_then(|accumulator| accumulator.checked_mul(10))
.and_then(|accumulator| accumulator.checked_add(d));
(digits, accumulator.1 + 1)
})
}
/// Read a decimal fraction.
pub fn read_fraction<I: Iterator<Item = char>>(
mut iter: Peekable<I>,
mut divisor: f64,
value: f64,
) -> (f64, usize) {
match iter.peek() {
Some(c) if is_decimal_point(*c) => (),
_ => return (value, 0),
}
iter.next();
iter.take_while(is_ascii_digit)
.map(|d| d as i64 - '0' as i64)
.fold((value, 1), |accumulator, d| {
divisor *= 10f64;
(accumulator.0 + d as f64 / divisor, accumulator.1 + 1)
})
}
/// Reads an exponent from an iterator over chars, for example `e100`.
pub fn read_exponent<I: Iterator<Item = char>>(mut iter: Peekable<I>) -> Option<i32> {
match iter.peek() {
Some(c) if is_exponent_char(*c) => (),
_ => return None,
}
iter.next();
match iter.peek() {
None => None,
Some(&'-') => {
iter.next();
read_numbers(iter).0.map(|exp| -exp.to_i32().unwrap_or(0))
},
Some(&'+') => {
iter.next();
read_numbers(iter).0.map(|exp| exp.to_i32().unwrap_or(0))
},
Some(_) => read_numbers(iter).0.map(|exp| exp.to_i32().unwrap_or(0)),
}
}
/// Join a set of strings with a given delimiter `join`.
pub fn str_join<I, T>(strs: I, join: &str) -> String
where
I: IntoIterator<Item = T>,
T: AsRef<str>,
{
strs.into_iter()
.enumerate()
.fold(String::new(), |mut acc, (i, s)| {
if i > 0 {
acc.push_str(join);
}
acc.push_str(s.as_ref());
acc
})
}
/// Returns true if a given string has a given prefix with case-insensitive match.
pub fn starts_with_ignore_ascii_case(string: &str, prefix: &str) -> bool {
string.len() >= prefix.len() &&
string.as_bytes()[0..prefix.len()].eq_ignore_ascii_case(prefix.as_bytes())
}
/// Returns an ascii lowercase version of a string, only allocating if needed.
pub fn string_as_ascii_lowercase<'a>(input: &'a str) -> Cow<'a, str> {
if input.bytes().any(|c| matches!(c, b'A'..=b'Z')) {
input.to_ascii_lowercase().into()
} else {
// Already ascii lowercase.
Cow::Borrowed(input)
}
}
/// To avoid accidentally instantiating multiple monomorphizations of large
/// serialization routines, we define explicit concrete types and require
/// them in those routines. This primarily avoids accidental mixing of UTF8
/// with UTF16 serializations in Gecko.
#[cfg(feature = "gecko")]
pub type CssStringWriter = ::nsstring::nsAString;
/// String type that coerces to CssStringWriter, used when serialization code
/// needs to allocate a temporary string.
#[cfg(feature = "gecko")]
pub type CssString = ::nsstring::nsString;
/// Certain serialization code needs to interact with borrowed strings, which
/// are sometimes native UTF8 Rust strings, and other times serialized UTF16
/// strings. This enum multiplexes the two cases.
#[cfg(feature = "gecko")]
pub enum CssStringBorrow<'a> {
/// A borrow of a UTF16 CssString.
UTF16(&'a ::nsstring::nsString),
/// A borrow of a regular Rust UTF8 string.
UTF8(&'a str),
}
#[cfg(feature = "gecko")]
impl<'a> CssStringBorrow<'a> {
/// Writes the borrowed string to the provided writer.
pub fn append_to(&self, dest: &mut CssStringWriter) -> fmt::Result {
match *self {
CssStringBorrow::UTF16(s) => {
dest.append(s);
Ok(())
},
CssStringBorrow::UTF8(s) => dest.write_str(s),
}
}
/// Returns true of the borrowed string is empty.
pub fn is_empty(&self) -> bool {
match *self {
CssStringBorrow::UTF16(s) => s.is_empty(),
CssStringBorrow::UTF8(s) => s.is_empty(),
}
}
}
#[cfg(feature = "gecko")]
impl<'a> From<&'a str> for CssStringBorrow<'a> {
fn from(s: &'a str) -> Self {
CssStringBorrow::UTF8(s)
}
}
#[cfg(feature = "gecko")]
impl<'a> From<&'a ::nsstring::nsString> for CssStringBorrow<'a> {
fn from(s: &'a ::nsstring::nsString) -> Self {
CssStringBorrow::UTF16(s)
}
}
/// String. The comments for the Gecko types explain the need for this abstraction.
#[cfg(feature = "servo")]
pub type CssStringWriter = String;
/// String. The comments for the Gecko types explain the need for this abstraction.
#[cfg(feature = "servo")]
pub type CssString = String;
/// Borrowed string. The comments for the Gecko types explain the need for this abstraction.
#[cfg(feature = "servo")]
pub struct CssStringBorrow<'a>(&'a str);
#[cfg(feature = "servo")]
impl<'a> CssStringBorrow<'a> {
/// Appends the borrowed string to the given string.
pub fn append_to(&self, dest: &mut CssStringWriter) -> fmt::Result {
dest.write_str(self.0)
}
/// Returns true if the borrowed string is empty.
pub fn is_empty(&self) -> bool {
self.0.is_empty()
}
}
#[cfg(feature = "servo")]
impl<'a> From<&'a str> for CssStringBorrow<'a> {
fn from(s: &'a str) -> Self {
CssStringBorrow(s)
}
}
#[cfg(feature = "servo")]
impl<'a> From<&'a String> for CssStringBorrow<'a> {
fn from(s: &'a String) -> Self {
CssStringBorrow(&*s)
}
}