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fix MIRI error in header::Iter (#642)
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seanmonstar committed Nov 13, 2023
1 parent 818269d commit 03c6e74
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Showing 2 changed files with 45 additions and 11 deletions.
55 changes: 44 additions & 11 deletions src/header/map.rs
Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,9 @@ pub struct HeaderMap<T = HeaderValue> {
/// more than once if it has more than one associated value.
#[derive(Debug)]
pub struct Iter<'a, T> {
inner: IterMut<'a, T>,
map: &'a HeaderMap<T>,
entry: usize,
cursor: Option<Cursor>,
}

/// `HeaderMap` mutable entry iterator
Expand Down Expand Up @@ -811,12 +813,9 @@ impl<T> HeaderMap<T> {
/// ```
pub fn iter(&self) -> Iter<'_, T> {
Iter {
inner: IterMut {
map: self as *const _ as *mut _,
entry: 0,
cursor: self.entries.first().map(|_| Cursor::Head),
lt: PhantomData,
},
map: self,
entry: 0,
cursor: self.entries.first().map(|_| Cursor::Head),
}
}

Expand Down Expand Up @@ -2078,13 +2077,47 @@ impl<'a, T> Iterator for Iter<'a, T> {
type Item = (&'a HeaderName, &'a T);

fn next(&mut self) -> Option<Self::Item> {
self.inner
.next_unsafe()
.map(|(key, ptr)| (key, unsafe { &*ptr }))
use self::Cursor::*;

if self.cursor.is_none() {
if (self.entry + 1) >= self.map.entries.len() {
return None;
}

self.entry += 1;
self.cursor = Some(Cursor::Head);
}

let entry = &self.map.entries[self.entry];

match self.cursor.unwrap() {
Head => {
self.cursor = entry.links.map(|l| Values(l.next));
Some((&entry.key, &entry.value))
}
Values(idx) => {
let extra = &self.map.extra_values[idx];

match extra.next {
Link::Entry(_) => self.cursor = None,
Link::Extra(i) => self.cursor = Some(Values(i)),
}

Some((&entry.key, &extra.value))
}
}
}

fn size_hint(&self) -> (usize, Option<usize>) {
self.inner.size_hint()
let map = self.map;
debug_assert!(map.entries.len() >= self.entry);

let lower = map.entries.len() - self.entry;
// We could pessimistically guess at the upper bound, saying
// that its lower + map.extra_values.len(). That could be
// way over though, such as if we're near the end, and have
// already gone through several extra values...
(lower, None)
}
}

Expand Down
1 change: 1 addition & 0 deletions tests/header_map_fuzz.rs
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ use rand::{Rng, SeedableRng};

use std::collections::HashMap;

#[cfg(not(miri))]
#[test]
fn header_map_fuzz() {
fn prop(fuzz: Fuzz) -> TestResult {
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