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// 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 chacters to indicate the parts of the request. For example, a forward slash
//! indicates a path. In order for that charcter to exist outside of a path separator, that
//! charcter would need to be encoded.
//!
//! Percent encoding replaces reserved charcters with the `%` escape charcter followed by hexidecimal
//! ASCII representaton. For non-ASCII charcters that are percent encoded, a UTF-8 byte sequence
//! becomes percent encoded. A simple example can be seen when the space literal is replaced with
//! `%20`.
//!
//! Percent encoding is further complicated by the fact that different parts of an URL have
//! different encoding requirements. In order to support the variety of encoding requirements,
//! `url::percent_encoding` includes different *encode sets*.
//! See [URL Standard](https://url.spec.whatwg.org/#percent-encoded-bytes) for details.
//!
//! This module provides some `*_ENCODE_SET` constants.
//! If a different set is required, it can be created with
//! the [`define_encode_set!`](../macro.define_encode_set!.html) macro.
//!
//! # Examples
//!
//! ```
//! use url::percent_encoding::{utf8_percent_encode, DEFAULT_ENCODE_SET};
//!
//! assert_eq!(utf8_percent_encode("foo bar?", DEFAULT_ENCODE_SET).to_string(), "foo%20bar%3F");
//! ```
use std::ascii::AsciiExt;
use std::borrow::Cow;
use std::fmt;
use std::slice;
use std::str;
/// Represents a set of characters / bytes that should be percent-encoded.
///
/// See [encode sets specification](http://url.spec.whatwg.org/#simple-encode-set).
///
/// Different characters need to be encoded in different parts of an URL.
/// For example, a literal `?` question mark in an URL’s path would indicate
/// the start of the query string.
/// A question mark meant to be part of the path therefore needs to be percent-encoded.
/// In the query string however, a question mark does not have any special meaning
/// and does not need to be percent-encoded.
///
/// A few sets are defined in this module.
/// Use the [`define_encode_set!`](../macro.define_encode_set!.html) macro to define different ones.
pub trait EncodeSet: Clone {
/// Called with UTF-8 bytes rather than code points.
/// Should return true for all non-ASCII bytes.
fn contains(&self, byte: u8) -> bool;
}
/// Define a new struct
/// that implements the [`EncodeSet`](percent_encoding/trait.EncodeSet.html) trait,
/// for use in [`percent_decode()`](percent_encoding/fn.percent_encode.html)
/// and related functions.
///
/// Parameters are characters to include in the set in addition to those of the base set.
/// See [encode sets specification](http://url.spec.whatwg.org/#simple-encode-set).
///
/// Example
/// =======
///
/// ```rust
/// #[macro_use] extern crate percent_encoding;
/// use percent_encoding::{utf8_percent_encode, SIMPLE_ENCODE_SET};
/// define_encode_set! {
/// /// This encode set is used in the URL parser for query strings.
/// pub QUERY_ENCODE_SET = [SIMPLE_ENCODE_SET] | {' ', '"', '#', '<', '>'}
/// }
/// # fn main() {
/// assert_eq!(utf8_percent_encode("foo bar", QUERY_ENCODE_SET).collect::<String>(), "foo%20bar");
/// # }
/// ```
#[macro_export]
macro_rules! define_encode_set {
($(#[$attr: meta])* pub $name: ident = [$base_set: expr] | {$($ch: pat),*}) => {
$(#[$attr])*
#[derive(Copy, Clone, Debug)]
#[allow(non_camel_case_types)]
pub struct $name;
impl $crate::EncodeSet for $name {
#[inline]
fn contains(&self, byte: u8) -> bool {
match byte as char {
$(
$ch => true,
)*
_ => $base_set.contains(byte)
}
}
}
}
}
/// This encode set is used for the path of cannot-be-a-base URLs.
///
/// All ASCII charcters less than hexidecimal 20 and greater than 7E are encoded. This includes
/// special charcters such as line feed, carriage return, NULL, etc.
#[derive(Copy, Clone, Debug)]
#[allow(non_camel_case_types)]
pub struct SIMPLE_ENCODE_SET;
impl EncodeSet for SIMPLE_ENCODE_SET {
#[inline]
fn contains(&self, byte: u8) -> bool {
byte < 0x20 || byte > 0x7E
}
}
define_encode_set! {
/// This encode set is used in the URL parser for query strings.
///
/// Aside from special chacters defined in the [`SIMPLE_ENCODE_SET`](struct.SIMPLE_ENCODE_SET.html),
/// space, double quote ("), hash (#), and inequality qualifiers (<), (>) are encoded.
pub QUERY_ENCODE_SET = [SIMPLE_ENCODE_SET] | {' ', '"', '#', '<', '>'}
}
define_encode_set! {
/// This encode set is used for path components.
///
/// Aside from special chacters defined in the [`SIMPLE_ENCODE_SET`](struct.SIMPLE_ENCODE_SET.html),
/// space, double quote ("), hash (#), inequality qualifiers (<), (>), backtick (`),
/// question mark (?), and curly brackets ({), (}) are encoded.
pub DEFAULT_ENCODE_SET = [QUERY_ENCODE_SET] | {'`', '?', '{', '}'}
}
define_encode_set! {
/// This encode set is used for on '/'-separated path segment
///
/// Aside from special chacters defined in the [`SIMPLE_ENCODE_SET`](struct.SIMPLE_ENCODE_SET.html),
/// space, double quote ("), hash (#), inequality qualifiers (<), (>), backtick (`),
/// question mark (?), and curly brackets ({), (}), percent sign (%), forward slash (/) are
/// encoded.
pub PATH_SEGMENT_ENCODE_SET = [DEFAULT_ENCODE_SET] | {'%', '/'}
}
define_encode_set! {
/// This encode set is used for username and password.
///
/// Aside from special chacters defined in the [`SIMPLE_ENCODE_SET`](struct.SIMPLE_ENCODE_SET.html),
/// space, double quote ("), hash (#), inequality qualifiers (<), (>), backtick (`),
/// question mark (?), and curly brackets ({), (}), forward slash (/), colon (:), semi-colon (;),
/// equality (=), at (@), backslash (\\), square brackets ([), (]), caret (\^), and pipe (|) are
/// encoded.
pub USERINFO_ENCODE_SET = [DEFAULT_ENCODE_SET] | {
'/', ':', ';', '=', '@', '[', '\\', ']', '^', '|'
}
}
/// Return the percent-encoding of the given bytes.
///
/// This is unconditional, unlike `percent_encode()` which uses an encode set.
///
/// # Examples
///
/// ```
/// use url::percent_encoding::percent_encode_byte;
///
/// assert_eq!("foo bar".bytes().map(percent_encode_byte).collect::<String>(),
/// "%66%6F%6F%20%62%61%72");
/// ```
pub fn percent_encode_byte(byte: u8) -> &'static str {
let index = usize::from(byte) * 3;
&"\
%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\
"[index..index + 3]
}
/// Percent-encode the given bytes with the given encode set.
///
/// The encode set define which bytes (in addition to non-ASCII and controls)
/// need to be percent-encoded.
/// The choice of this set depends on context.
/// For example, `?` needs to be encoded in an URL path but not in a query string.
///
/// The return value is an iterator of `&str` slices (so it has a `.collect::<String>()` method)
/// that also implements `Display` and `Into<Cow<str>>`.
/// The latter returns `Cow::Borrowed` when none of the bytes in `input`
/// are in the given encode set.
///
/// # Examples
///
/// ```
/// use url::percent_encoding::{percent_encode, DEFAULT_ENCODE_SET};
///
/// assert_eq!(percent_encode(b"foo bar?", DEFAULT_ENCODE_SET).to_string(), "foo%20bar%3F");
/// ```
#[inline]
pub fn percent_encode<E: EncodeSet>(input: &[u8], encode_set: E) -> PercentEncode<E> {
PercentEncode {
bytes: input,
encode_set: encode_set,
}
}
/// Percent-encode the UTF-8 encoding of the given string.
///
/// See `percent_encode()` for how to use the return value.
///
/// # Examples
///
/// ```
/// use url::percent_encoding::{utf8_percent_encode, DEFAULT_ENCODE_SET};
///
/// assert_eq!(utf8_percent_encode("foo bar?", DEFAULT_ENCODE_SET).to_string(), "foo%20bar%3F");
/// ```
#[inline]
pub fn utf8_percent_encode<E: EncodeSet>(input: &str, encode_set: E) -> PercentEncode<E> {
percent_encode(input.as_bytes(), encode_set)
}
/// The return type of `percent_encode()` and `utf8_percent_encode()`.
#[derive(Clone, Debug)]
pub struct PercentEncode<'a, E: EncodeSet> {
bytes: &'a [u8],
encode_set: E,
}
impl<'a, E: EncodeSet> Iterator for PercentEncode<'a, E> {
type Item = &'a str;
fn next(&mut self) -> Option<&'a str> {
if let Some((&first_byte, remaining)) = self.bytes.split_first() {
if self.encode_set.contains(first_byte) {
self.bytes = remaining;
Some(percent_encode_byte(first_byte))
} else {
assert!(first_byte.is_ascii());
for (i, &byte) in remaining.iter().enumerate() {
if self.encode_set.contains(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) })
} else {
assert!(byte.is_ascii());
}
}
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, E: EncodeSet> fmt::Display for PercentEncode<'a, E> {
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
for c in (*self).clone() {
formatter.write_str(c)?
}
Ok(())
}
}
impl<'a, E: EncodeSet> From<PercentEncode<'a, E>> for Cow<'a, str> {
fn from(mut iter: PercentEncode<'a, E>) -> 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 bytes.
///
/// The return value is an iterator of decoded `u8` bytes
/// that also implements `Into<Cow<u8>>`
/// (which returns `Cow::Borrowed` when `input` contains no percent-encoded sequence)
/// and has `decode_utf8()` and `decode_utf8_lossy()` methods.
///
/// # Examples
///
/// ```
/// use url::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 initial_iter = iter.clone();
let h = iter.next().and_then(|&b| (b as char).to_digit(16));
let l = iter.next().and_then(|&b| (b as char).to_digit(16));
if let (Some(h), Some(l)) = (h, l) {
Some(h as u8 * 0x10 + l as u8)
} else {
*iter = initial_iter;
None
}
}
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 / 3, Some(bytes))
}
}
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.
pub 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.
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.
pub fn decode_utf8_lossy(self) -> Cow<'a, str> {
decode_utf8_lossy(self.clone().into())
}
}
fn decode_utf8_lossy(input: Cow<[u8]>) -> Cow<str> {
match input {
Cow::Borrowed(bytes) => String::from_utf8_lossy(bytes),
Cow::Owned(bytes) => {
let raw_utf8: *const [u8];
match String::from_utf8_lossy(&bytes) {
Cow::Borrowed(utf8) => raw_utf8 = utf8.as_bytes(),
Cow::Owned(s) => return s.into(),
}
// from_utf8_lossy returned a borrow of `bytes` unchanged.
debug_assert!(raw_utf8 == &*bytes as *const [u8]);
// Reuse the existing `Vec` allocation.
unsafe { String::from_utf8_unchecked(bytes) }.into()
}
}
}