From 0faba12c6809116abeae6662aa02738cf709f003 Mon Sep 17 00:00:00 2001
From: Lukas Markeffsky <@>
Date: Thu, 1 Feb 2024 00:40:07 +0100
Subject: [PATCH] bonus asserts + test
---
src/lib.rs | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/src/lib.rs b/src/lib.rs
index 46b9828..f76cb79 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -135,6 +135,7 @@ pub struct Unclaimed<T> {
impl<T> Unclaimed<T> {
pub fn claim(self, value: T) -> Xrc<T> {
unsafe {
+ debug_assert_eq!((*self.ptr.as_ptr()).state.get(), STATE_UNCLAIMED);
(*self.ptr.as_ptr()).state.set(STATE_SHARED_INIT);
}
@@ -163,6 +164,7 @@ impl<T: ?Sized> Drop for Xrc<T> {
let state_ref = unsafe { &(*root.as_ptr()).state };
let state = state_ref.get();
+ debug_assert!(state <= STATE_SHARED_MAX);
if state != STATE_SHARED_INIT {
state_ref.set(state - 1);
return;
@@ -184,6 +186,7 @@ impl<T> Clone for Xrc<T> {
let state_ref = unsafe { &(*root.as_ptr()).state };
let state = state_ref.get();
+ debug_assert!(state <= STATE_SHARED_MAX);
if state == STATE_SHARED_MAX {
panic!("ref count overflow");
}
@@ -243,6 +246,7 @@ mod tests {
use std::pin::pin;
use std::ptr;
use std::rc::Rc;
+ use std::panic::{self, AssertUnwindSafe};
fn iter_pinned_mut<T>(slice: Pin<&mut [T]>) -> impl Iterator<Item = Pin<&mut T>> {
unsafe {
@@ -260,6 +264,21 @@ mod tests {
assert_eq!(xrc.0, 42);
}
+ #[test]
+ fn unpin_hack() {
+ let mut root = pin!(Root::new());
+ let xrc = root.as_mut().unclaimed().claim(NoReclaim(42));
+
+ let res = panic::catch_unwind(AssertUnwindSafe(|| {
+ // This must not create an unique borrow ...
+ let _ = root.unclaimed();
+ }));
+ assert!(res.is_err());
+
+ // ... to not invalidate this shared read-only borrow.
+ assert_eq!(xrc.0, 42);
+ }
+
#[test]
#[ignore = "will abort"]
fn abort() {
--
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