Struct BorrowedMap

pub struct BorrowedMap<'shm> { /* private fields */ }

A wrapper around an memmap2::MmapMut to prevent one from accidentally calling Shm::map twice on the same Shm (which could very easily introduce memory unsoundness). To use the contained map, just call BorrowedMap::map. One cannot safely move the map out of this struct, as that would easily allow them to break the lifetime-dependent relationship between this map and the Shm it’s mapped onto.

To be clear: This risk of memory unsafety does not come from an actual borrowing of memory between the Shm and the MmapMut - a MmapMut can be dropped before or after the Shm which it is mapped from and nothing bad will happen. The issue comes when two MmapMuts are mapped from the same Shm - this could allow e.g. something to borrow from one MmapMut, then the other MmapMut could be shrunk, thus invalidating the references from the first map.

Implementations

impl BorrowedMap<'_>

pub fn map(&mut self) -> &mut MmapMut

pub unsafe fn into_map(self) -> MmapMut

Take the inner MmapMut out of this wrapper.

Safety

This can can unsoundness if another Mmap is created from the Shm that this was derived from. Read the struct-level documentation for more details.

Trait Implementations

impl<'shm> Debug for BorrowedMap<'shm>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.