1 files changed, 315 insertions, 0 deletions
diff --git a/third_party/rust/idna/src/punycode.rs b/third_party/rust/idna/src/punycode.rs
new file mode 100644
index 0000000000..21955f3596
--- /dev/null
+++ b/third_party/rust/idna/src/punycode.rs
@@ -0,0 +1,315 @@
+// Copyright 2013 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.
+
+//! Punycode ([RFC 3492](http://tools.ietf.org/html/rfc3492)) implementation.
+//!
+//! Since Punycode fundamentally works on unicode code points,
+//! `encode` and `decode` take and return slices and vectors of `char`.
+//! `encode_str` and `decode_to_string` provide convenience wrappers
+//! that convert from and to Rust’s UTF-8 based `str` and `String` types.
+
+use std::char;
+use std::u32;
+
+// Bootstring parameters for Punycode
+static BASE: u32 = 36;
+static T_MIN: u32 = 1;
+static T_MAX: u32 = 26;
+static SKEW: u32 = 38;
+static DAMP: u32 = 700;
+static INITIAL_BIAS: u32 = 72;
+static INITIAL_N: u32 = 0x80;
+static DELIMITER: char = '-';
+
+#[inline]
+fn adapt(mut delta: u32, num_points: u32, first_time: bool) -> u32 {
+    delta /= if first_time { DAMP } else { 2 };
+    delta += delta / num_points;
+    let mut k = 0;
+    while delta > ((BASE - T_MIN) * T_MAX) / 2 {
+        delta /= BASE - T_MIN;
+        k += BASE;
+    }
+    k + (((BASE - T_MIN + 1) * delta) / (delta + SKEW))
+}
+
+/// Convert Punycode to an Unicode `String`.
+///
+/// This is a convenience wrapper around `decode`.
+#[inline]
+pub fn decode_to_string(input: &str) -> Option<String> {
+    decode(input).map(|chars| chars.into_iter().collect())
+}
+
+/// Convert Punycode to Unicode.
+///
+/// Return None on malformed input or overflow.
+/// Overflow can only happen on inputs that take more than
+/// 63 encoded bytes, the DNS limit on domain name labels.
+pub fn decode(input: &str) -> Option<Vec<char>> {
+    Some(Decoder::default().decode(input).ok()?.collect())
+}
+
+#[derive(Default)]
+pub(crate) struct Decoder {
+    insertions: Vec<(usize, char)>,
+}
+
+impl Decoder {
+    /// Split the input iterator and return a Vec with insertions of encoded characters
+    pub(crate) fn decode<'a>(&'a mut self, input: &'a str) -> Result<Decode<'a>, ()> {
+        self.insertions.clear();
+        // Handle "basic" (ASCII) code points.
+        // They are encoded as-is before the last delimiter, if any.
+        let (base, input) = match input.rfind(DELIMITER) {
+            None => ("", input),
+            Some(position) => (
+                &input[..position],
+                if position > 0 {
+                    &input[position + 1..]
+                } else {
+                    input
+                },
+            ),
+        };
+
+        if !base.is_ascii() {
+            return Err(());
+        }
+
+        let base_len = base.len();
+        let mut length = base_len as u32;
+        let mut code_point = INITIAL_N;
+        let mut bias = INITIAL_BIAS;
+        let mut i = 0;
+        let mut iter = input.bytes();
+        loop {
+            let previous_i = i;
+            let mut weight = 1;
+            let mut k = BASE;
+            let mut byte = match iter.next() {
+                None => break,
+                Some(byte) => byte,
+            };
+
+            // Decode a generalized variable-length integer into delta,
+            // which gets added to i.
+            loop {
+                let digit = match byte {
+                    byte @ b'0'..=b'9' => byte - b'0' + 26,
+                    byte @ b'A'..=b'Z' => byte - b'A',
+                    byte @ b'a'..=b'z' => byte - b'a',
+                    _ => return Err(()),
+                } as u32;
+                if digit > (u32::MAX - i) / weight {
+                    return Err(()); // Overflow
+                }
+                i += digit * weight;
+                let t = if k <= bias {
+                    T_MIN
+                } else if k >= bias + T_MAX {
+                    T_MAX
+                } else {
+                    k - bias
+                };
+                if digit < t {
+                    break;
+                }
+                if weight > u32::MAX / (BASE - t) {
+                    return Err(()); // Overflow
+                }
+                weight *= BASE - t;
+                k += BASE;
+                byte = match iter.next() {
+                    None => return Err(()), // End of input before the end of this delta
+                    Some(byte) => byte,
+                };
+            }
+
+            bias = adapt(i - previous_i, length + 1, previous_i == 0);
+            if i / (length + 1) > u32::MAX - code_point {
+                return Err(()); // Overflow
+            }
+
+            // i was supposed to wrap around from length+1 to 0,
+            // incrementing code_point each time.
+            code_point += i / (length + 1);
+            i %= length + 1;
+            let c = match char::from_u32(code_point) {
+                Some(c) => c,
+                None => return Err(()),
+            };
+
+            // Move earlier insertions farther out in the string
+            for (idx, _) in &mut self.insertions {
+                if *idx >= i as usize {
+                    *idx += 1;
+                }
+            }
+            self.insertions.push((i as usize, c));
+            length += 1;
+            i += 1;
+        }
+
+        self.insertions.sort_by_key(|(i, _)| *i);
+        Ok(Decode {
+            base: base.chars(),
+            insertions: &self.insertions,
+            inserted: 0,
+            position: 0,
+            len: base_len + self.insertions.len(),
+        })
+    }
+}
+
+pub(crate) struct Decode<'a> {
+    base: std::str::Chars<'a>,
+    pub(crate) insertions: &'a [(usize, char)],
+    inserted: usize,
+    position: usize,
+    len: usize,
+}
+
+impl<'a> Iterator for Decode<'a> {
+    type Item = char;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        loop {
+            match self.insertions.get(self.inserted) {
+                Some((pos, c)) if *pos == self.position => {
+                    self.inserted += 1;
+                    self.position += 1;
+                    return Some(*c);
+                }
+                _ => {}
+            }
+            if let Some(c) = self.base.next() {
+                self.position += 1;
+                return Some(c);
+            } else if self.inserted >= self.insertions.len() {
+                return None;
+            }
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len - self.position;
+        (len, Some(len))
+    }
+}
+
+impl<'a> ExactSizeIterator for Decode<'a> {
+    fn len(&self) -> usize {
+        self.len - self.position
+    }
+}
+
+/// Convert an Unicode `str` to Punycode.
+///
+/// This is a convenience wrapper around `encode`.
+#[inline]
+pub fn encode_str(input: &str) -> Option<String> {
+    let mut buf = String::with_capacity(input.len());
+    encode_into(input.chars(), &mut buf).ok().map(|()| buf)
+}
+
+/// Convert Unicode to Punycode.
+///
+/// Return None on overflow, which can only happen on inputs that would take more than
+/// 63 encoded bytes, the DNS limit on domain name labels.
+pub fn encode(input: &[char]) -> Option<String> {
+    let mut buf = String::with_capacity(input.len());
+    encode_into(input.iter().copied(), &mut buf)
+        .ok()
+        .map(|()| buf)
+}
+
+pub(crate) fn encode_into<I>(input: I, output: &mut String) -> Result<(), ()>
+where
+    I: Iterator<Item = char> + Clone,
+{
+    // Handle "basic" (ASCII) code points. They are encoded as-is.
+    let (mut input_length, mut basic_length) = (0, 0);
+    for c in input.clone() {
+        input_length += 1;
+        if c.is_ascii() {
+            output.push(c);
+            basic_length += 1;
+        }
+    }
+
+    if basic_length > 0 {
+        output.push('-')
+    }
+    let mut code_point = INITIAL_N;
+    let mut delta = 0;
+    let mut bias = INITIAL_BIAS;
+    let mut processed = basic_length;
+    while processed < input_length {
+        // All code points < code_point have been handled already.
+        // Find the next larger one.
+        let min_code_point = input
+            .clone()
+            .map(|c| c as u32)
+            .filter(|&c| c >= code_point)
+            .min()
+            .unwrap();
+        if min_code_point - code_point > (u32::MAX - delta) / (processed + 1) {
+            return Err(()); // Overflow
+        }
+        // Increase delta to advance the decoder’s <code_point,i> state to <min_code_point,0>
+        delta += (min_code_point - code_point) * (processed + 1);
+        code_point = min_code_point;
+        for c in input.clone() {
+            let c = c as u32;
+            if c < code_point {
+                delta += 1;
+                if delta == 0 {
+                    return Err(()); // Overflow
+                }
+            }
+            if c == code_point {
+                // Represent delta as a generalized variable-length integer:
+                let mut q = delta;
+                let mut k = BASE;
+                loop {
+                    let t = if k <= bias {
+                        T_MIN
+                    } else if k >= bias + T_MAX {
+                        T_MAX
+                    } else {
+                        k - bias
+                    };
+                    if q < t {
+                        break;
+                    }
+                    let value = t + ((q - t) % (BASE - t));
+                    output.push(value_to_digit(value));
+                    q = (q - t) / (BASE - t);
+                    k += BASE;
+                }
+                output.push(value_to_digit(q));
+                bias = adapt(delta, processed + 1, processed == basic_length);
+                delta = 0;
+                processed += 1;
+            }
+        }
+        delta += 1;
+        code_point += 1;
+    }
+    Ok(())
+}
+
+#[inline]
+fn value_to_digit(value: u32) -> char {
+    match value {
+        0..=25 => (value as u8 + b'a') as char,       // a..z
+        26..=35 => (value as u8 - 26 + b'0') as char, // 0..9
+        _ => panic!(),
+    }
+}