diff options
Diffstat (limited to 'third_party/rust/percent-encoding/src')
| -rw-r--r-- | third_party/rust/percent-encoding/src/lib.rs | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/third_party/rust/percent-encoding/src/lib.rs b/third_party/rust/percent-encoding/src/lib.rs new file mode 100644 index 0000000000..e02a439498 --- /dev/null +++ b/third_party/rust/percent-encoding/src/lib.rs @@ -0,0 +1,477 @@ +// Copyright 2013-2016 The rust-url developers. +// +// 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. + +//! URLs use special characters to indicate the parts of the request. +//! For example, a `?` question mark marks the end of a path and the start of a query string. +//! In order for that character to exist inside a path, it needs to be encoded differently. +//! +//! Percent encoding replaces reserved characters with the `%` escape character +//! followed by a byte value as two hexadecimal digits. +//! For example, an ASCII space is replaced with `%20`. +//! +//! When encoding, the set of characters that can (and should, for readability) be left alone +//! depends on the context. +//! The `?` question mark mentioned above is not a separator when used literally +//! inside of a query string, and therefore does not need to be encoded. +//! The [`AsciiSet`] parameter of [`percent_encode`] and [`utf8_percent_encode`] +//! lets callers configure this. +//! +//! This crate deliberately does not provide many different sets. +//! Users should consider in what context the encoded string will be used, +//! read relevant specifications, and define their own set. +//! This is done by using the `add` method of an existing set. +//! +//! # Examples +//! +//! ``` +//! use percent_encoding::{utf8_percent_encode, AsciiSet, CONTROLS}; +//! +//! /// https://url.spec.whatwg.org/#fragment-percent-encode-set +//! const FRAGMENT: &AsciiSet = &CONTROLS.add(b' ').add(b'"').add(b'<').add(b'>').add(b'`'); +//! +//! assert_eq!(utf8_percent_encode("foo <bar>", FRAGMENT).to_string(), "foo%20%3Cbar%3E"); +//! ``` +#![no_std] + +// For forwards compatibility +#[cfg(feature = "std")] +extern crate std as _; + +#[cfg(feature = "alloc")] +extern crate alloc; + +#[cfg(feature = "alloc")] +use alloc::{ + borrow::{Cow, ToOwned}, + string::String, + vec::Vec, +}; +use core::{fmt, mem, slice, str}; + +/// Represents a set of characters or bytes in the ASCII range. +/// +/// This is used in [`percent_encode`] and [`utf8_percent_encode`]. +/// This is similar to [percent-encode sets](https://url.spec.whatwg.org/#percent-encoded-bytes). +/// +/// Use the `add` method of an existing set to define a new set. For example: +/// +/// ``` +/// use percent_encoding::{AsciiSet, CONTROLS}; +/// +/// /// https://url.spec.whatwg.org/#fragment-percent-encode-set +/// const FRAGMENT: &AsciiSet = &CONTROLS.add(b' ').add(b'"').add(b'<').add(b'>').add(b'`'); +/// ``` +pub struct AsciiSet { + mask: [Chunk; ASCII_RANGE_LEN / BITS_PER_CHUNK], +} + +type Chunk = u32; + +const ASCII_RANGE_LEN: usize = 0x80; + +const BITS_PER_CHUNK: usize = 8 * mem::size_of::<Chunk>(); + +impl AsciiSet { + /// Called with UTF-8 bytes rather than code points. + /// Not used for non-ASCII bytes. + const fn contains(&self, byte: u8) -> bool { + let chunk = self.mask[byte as usize / BITS_PER_CHUNK]; + let mask = 1 << (byte as usize % BITS_PER_CHUNK); + (chunk & mask) != 0 + } + + fn should_percent_encode(&self, byte: u8) -> bool { + !byte.is_ascii() || self.contains(byte) + } + + pub const fn add(&self, byte: u8) -> Self { + let mut mask = self.mask; + mask[byte as usize / BITS_PER_CHUNK] |= 1 << (byte as usize % BITS_PER_CHUNK); + AsciiSet { mask } + } + + pub const fn remove(&self, byte: u8) -> Self { + let mut mask = self.mask; + mask[byte as usize / BITS_PER_CHUNK] &= !(1 << (byte as usize % BITS_PER_CHUNK)); + AsciiSet { mask } + } +} + +/// The set of 0x00 to 0x1F (C0 controls), and 0x7F (DEL). +/// +/// Note that this includes the newline and tab characters, but not the space 0x20. +/// +/// <https://url.spec.whatwg.org/#c0-control-percent-encode-set> +pub const CONTROLS: &AsciiSet = &AsciiSet { + mask: [ + !0_u32, // C0: 0x00 to 0x1F (32 bits set) + 0, + 0, + 1 << (0x7F_u32 % 32), // DEL: 0x7F (one bit set) + ], +}; + +macro_rules! static_assert { + ($( $bool: expr, )+) => { + fn _static_assert() { + $( + let _ = mem::transmute::<[u8; $bool as usize], u8>; + )+ + } + } +} + +static_assert! { + CONTROLS.contains(0x00), + CONTROLS.contains(0x1F), + !CONTROLS.contains(0x20), + !CONTROLS.contains(0x7E), + CONTROLS.contains(0x7F), +} + +/// Everything that is not an ASCII letter or digit. +/// +/// This is probably more eager than necessary in any context. +pub const NON_ALPHANUMERIC: &AsciiSet = &CONTROLS + .add(b' ') + .add(b'!') + .add(b'"') + .add(b'#') + .add(b'$') + .add(b'%') + .add(b'&') + .add(b'\'') + .add(b'(') + .add(b')') + .add(b'*') + .add(b'+') + .add(b',') + .add(b'-') + .add(b'.') + .add(b'/') + .add(b':') + .add(b';') + .add(b'<') + .add(b'=') + .add(b'>') + .add(b'?') + .add(b'@') + .add(b'[') + .add(b'\\') + .add(b']') + .add(b'^') + .add(b'_') + .add(b'`') + .add(b'{') + .add(b'|') + .add(b'}') + .add(b'~'); + +/// Return the percent-encoding of the given byte. +/// +/// This is unconditional, unlike `percent_encode()` which has an `AsciiSet` parameter. +/// +/// # Examples +/// +/// ``` +/// use percent_encoding::percent_encode_byte; +/// +/// assert_eq!("foo bar".bytes().map(percent_encode_byte).collect::<String>(), +/// "%66%6F%6F%20%62%61%72"); +/// ``` +#[inline] +pub fn percent_encode_byte(byte: u8) -> &'static str { + static ENC_TABLE: &[u8; 768] = b"\ + %00%01%02%03%04%05%06%07%08%09%0A%0B%0C%0D%0E%0F\ + %10%11%12%13%14%15%16%17%18%19%1A%1B%1C%1D%1E%1F\ + %20%21%22%23%24%25%26%27%28%29%2A%2B%2C%2D%2E%2F\ + %30%31%32%33%34%35%36%37%38%39%3A%3B%3C%3D%3E%3F\ + %40%41%42%43%44%45%46%47%48%49%4A%4B%4C%4D%4E%4F\ + %50%51%52%53%54%55%56%57%58%59%5A%5B%5C%5D%5E%5F\ + %60%61%62%63%64%65%66%67%68%69%6A%6B%6C%6D%6E%6F\ + %70%71%72%73%74%75%76%77%78%79%7A%7B%7C%7D%7E%7F\ + %80%81%82%83%84%85%86%87%88%89%8A%8B%8C%8D%8E%8F\ + %90%91%92%93%94%95%96%97%98%99%9A%9B%9C%9D%9E%9F\ + %A0%A1%A2%A3%A4%A5%A6%A7%A8%A9%AA%AB%AC%AD%AE%AF\ + %B0%B1%B2%B3%B4%B5%B6%B7%B8%B9%BA%BB%BC%BD%BE%BF\ + %C0%C1%C2%C3%C4%C5%C6%C7%C8%C9%CA%CB%CC%CD%CE%CF\ + %D0%D1%D2%D3%D4%D5%D6%D7%D8%D9%DA%DB%DC%DD%DE%DF\ + %E0%E1%E2%E3%E4%E5%E6%E7%E8%E9%EA%EB%EC%ED%EE%EF\ + %F0%F1%F2%F3%F4%F5%F6%F7%F8%F9%FA%FB%FC%FD%FE%FF\ + "; + + let index = usize::from(byte) * 3; + // SAFETY: ENC_TABLE is ascii-only, so any subset if it should be + // ascii-only too, which is valid utf8. + unsafe { str::from_utf8_unchecked(&ENC_TABLE[index..index + 3]) } +} + +/// Percent-encode the given bytes with the given set. +/// +/// Non-ASCII bytes and bytes in `ascii_set` are encoded. +/// +/// The return type: +/// +/// * Implements `Iterator<Item = &str>` and therefore has a `.collect::<String>()` method, +/// * Implements `Display` and therefore has a `.to_string()` method, +/// * Implements `Into<Cow<str>>` borrowing `input` when none of its bytes are encoded. +/// +/// # Examples +/// +/// ``` +/// use percent_encoding::{percent_encode, NON_ALPHANUMERIC}; +/// +/// assert_eq!(percent_encode(b"foo bar?", NON_ALPHANUMERIC).to_string(), "foo%20bar%3F"); +/// ``` +#[inline] +pub fn percent_encode<'a>(input: &'a [u8], ascii_set: &'static AsciiSet) -> PercentEncode<'a> { + PercentEncode { + bytes: input, + ascii_set, + } +} + +/// Percent-encode the UTF-8 encoding of the given string. +/// +/// See [`percent_encode`] regarding the return type. +/// +/// # Examples +/// +/// ``` +/// use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC}; +/// +/// assert_eq!(utf8_percent_encode("foo bar?", NON_ALPHANUMERIC).to_string(), "foo%20bar%3F"); +/// ``` +#[inline] +pub fn utf8_percent_encode<'a>(input: &'a str, ascii_set: &'static AsciiSet) -> PercentEncode<'a> { + percent_encode(input.as_bytes(), ascii_set) +} + +/// The return type of [`percent_encode`] and [`utf8_percent_encode`]. +#[derive(Clone)] +pub struct PercentEncode<'a> { + bytes: &'a [u8], + ascii_set: &'static AsciiSet, +} + +impl<'a> Iterator for PercentEncode<'a> { + type Item = &'a str; + + fn next(&mut self) -> Option<&'a str> { + if let Some((&first_byte, remaining)) = self.bytes.split_first() { + if self.ascii_set.should_percent_encode(first_byte) { + self.bytes = remaining; + Some(percent_encode_byte(first_byte)) + } else { + // The unsafe blocks here are appropriate because the bytes are + // confirmed as a subset of UTF-8 in should_percent_encode. + for (i, &byte) in remaining.iter().enumerate() { + if self.ascii_set.should_percent_encode(byte) { + // 1 for first_byte + i for previous iterations of this loop + let (unchanged_slice, remaining) = self.bytes.split_at(1 + i); + self.bytes = remaining; + return Some(unsafe { str::from_utf8_unchecked(unchanged_slice) }); + } + } + let unchanged_slice = self.bytes; + self.bytes = &[][..]; + Some(unsafe { str::from_utf8_unchecked(unchanged_slice) }) + } + } else { + None + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.bytes.is_empty() { + (0, Some(0)) + } else { + (1, Some(self.bytes.len())) + } + } +} + +impl<'a> fmt::Display for PercentEncode<'a> { + fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result { + for c in (*self).clone() { + formatter.write_str(c)? + } + Ok(()) + } +} + +#[cfg(feature = "alloc")] +impl<'a> From<PercentEncode<'a>> for Cow<'a, str> { + fn from(mut iter: PercentEncode<'a>) -> Self { + match iter.next() { + None => "".into(), + Some(first) => match iter.next() { + None => first.into(), + Some(second) => { + let mut string = first.to_owned(); + string.push_str(second); + string.extend(iter); + string.into() + } + }, + } + } +} + +/// Percent-decode the given string. +/// +/// <https://url.spec.whatwg.org/#string-percent-decode> +/// +/// See [`percent_decode`] regarding the return type. +#[inline] +pub fn percent_decode_str(input: &str) -> PercentDecode<'_> { + percent_decode(input.as_bytes()) +} + +/// Percent-decode the given bytes. +/// +/// <https://url.spec.whatwg.org/#percent-decode> +/// +/// Any sequence of `%` followed by two hexadecimal digits is decoded. +/// The return type: +/// +/// * Implements `Into<Cow<u8>>` borrowing `input` when it contains no percent-encoded sequence, +/// * Implements `Iterator<Item = u8>` and therefore has a `.collect::<Vec<u8>>()` method, +/// * Has `decode_utf8()` and `decode_utf8_lossy()` methods. +/// +/// # Examples +/// +/// ``` +/// use percent_encoding::percent_decode; +/// +/// assert_eq!(percent_decode(b"foo%20bar%3f").decode_utf8().unwrap(), "foo bar?"); +/// ``` +#[inline] +pub fn percent_decode(input: &[u8]) -> PercentDecode<'_> { + PercentDecode { + bytes: input.iter(), + } +} + +/// The return type of [`percent_decode`]. +#[derive(Clone, Debug)] +pub struct PercentDecode<'a> { + bytes: slice::Iter<'a, u8>, +} + +fn after_percent_sign(iter: &mut slice::Iter<'_, u8>) -> Option<u8> { + let mut cloned_iter = iter.clone(); + let h = char::from(*cloned_iter.next()?).to_digit(16)?; + let l = char::from(*cloned_iter.next()?).to_digit(16)?; + *iter = cloned_iter; + Some(h as u8 * 0x10 + l as u8) +} + +impl<'a> Iterator for PercentDecode<'a> { + type Item = u8; + + fn next(&mut self) -> Option<u8> { + self.bytes.next().map(|&byte| { + if byte == b'%' { + after_percent_sign(&mut self.bytes).unwrap_or(byte) + } else { + byte + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let bytes = self.bytes.len(); + ((bytes + 2) / 3, Some(bytes)) + } +} + +#[cfg(feature = "alloc")] +impl<'a> From<PercentDecode<'a>> for Cow<'a, [u8]> { + fn from(iter: PercentDecode<'a>) -> Self { + match iter.if_any() { + Some(vec) => Cow::Owned(vec), + None => Cow::Borrowed(iter.bytes.as_slice()), + } + } +} + +impl<'a> PercentDecode<'a> { + /// If the percent-decoding is different from the input, return it as a new bytes vector. + #[cfg(feature = "alloc")] + fn if_any(&self) -> Option<Vec<u8>> { + let mut bytes_iter = self.bytes.clone(); + while bytes_iter.any(|&b| b == b'%') { + if let Some(decoded_byte) = after_percent_sign(&mut bytes_iter) { + let initial_bytes = self.bytes.as_slice(); + let unchanged_bytes_len = initial_bytes.len() - bytes_iter.len() - 3; + let mut decoded = initial_bytes[..unchanged_bytes_len].to_owned(); + decoded.push(decoded_byte); + decoded.extend(PercentDecode { bytes: bytes_iter }); + return Some(decoded); + } + } + // Nothing to decode + None + } + + /// Decode the result of percent-decoding as UTF-8. + /// + /// This is return `Err` when the percent-decoded bytes are not well-formed in UTF-8. + #[cfg(feature = "alloc")] + pub fn decode_utf8(self) -> Result<Cow<'a, str>, str::Utf8Error> { + match self.clone().into() { + Cow::Borrowed(bytes) => match str::from_utf8(bytes) { + Ok(s) => Ok(s.into()), + Err(e) => Err(e), + }, + Cow::Owned(bytes) => match String::from_utf8(bytes) { + Ok(s) => Ok(s.into()), + Err(e) => Err(e.utf8_error()), + }, + } + } + + /// Decode the result of percent-decoding as UTF-8, lossily. + /// + /// Invalid UTF-8 percent-encoded byte sequences will be replaced � U+FFFD, + /// the replacement character. + #[cfg(feature = "alloc")] + pub fn decode_utf8_lossy(self) -> Cow<'a, str> { + decode_utf8_lossy(self.clone().into()) + } +} + +#[cfg(feature = "alloc")] +fn decode_utf8_lossy(input: Cow<'_, [u8]>) -> Cow<'_, str> { + // Note: This function is duplicated in `form_urlencoded/src/query_encoding.rs`. + match input { + Cow::Borrowed(bytes) => String::from_utf8_lossy(bytes), + Cow::Owned(bytes) => { + match String::from_utf8_lossy(&bytes) { + Cow::Borrowed(utf8) => { + // If from_utf8_lossy returns a Cow::Borrowed, then we can + // be sure our original bytes were valid UTF-8. This is because + // if the bytes were invalid UTF-8 from_utf8_lossy would have + // to allocate a new owned string to back the Cow so it could + // replace invalid bytes with a placeholder. + + // First we do a debug_assert to confirm our description above. + let raw_utf8: *const [u8] = utf8.as_bytes(); + debug_assert!(raw_utf8 == &*bytes as *const [u8]); + + // Given we know the original input bytes are valid UTF-8, + // and we have ownership of those bytes, we re-use them and + // return a Cow::Owned here. + Cow::Owned(unsafe { String::from_utf8_unchecked(bytes) }) + } + Cow::Owned(s) => Cow::Owned(s), + } + } + } +} |