diff options
| -rw-r--r-- | rust/kernel/alloc/kvec.rs | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index 412a2fe3ce79..ebca0cfd31c6 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -320,6 +320,37 @@ where Ok(()) } + /// Removes the last element from a vector and returns it, or `None` if it is empty. + /// + /// # Examples + /// + /// ``` + /// let mut v = KVec::new(); + /// v.push(1, GFP_KERNEL)?; + /// v.push(2, GFP_KERNEL)?; + /// assert_eq!(&v, &[1, 2]); + /// + /// assert_eq!(v.pop(), Some(2)); + /// assert_eq!(v.pop(), Some(1)); + /// assert_eq!(v.pop(), None); + /// # Ok::<(), Error>(()) + /// ``` + pub fn pop(&mut self) -> Option<T> { + if self.is_empty() { + return None; + } + + let removed: *mut T = { + // SAFETY: We just checked that the length is at least one. + let slice = unsafe { self.dec_len(1) }; + // SAFETY: The argument to `dec_len` was 1 so this returns a slice of length 1. + unsafe { slice.get_unchecked_mut(0) } + }; + + // SAFETY: The guarantees of `dec_len` allow us to take ownership of this value. + Some(unsafe { removed.read() }) + } + /// Creates a new [`Vec`] instance with at least the given capacity. /// /// # Examples |