| use std::fs::File; |
| use std::io; |
| use std::ops::Deref; |
| |
| use crate::owning_ref::StableAddress; |
| |
| /// A trivial wrapper for [`memmap2::Mmap`] that implements [`StableAddress`]. |
| #[cfg(not(target_arch = "wasm32"))] |
| pub struct Mmap(memmap2::Mmap); |
| |
| #[cfg(target_arch = "wasm32")] |
| pub struct Mmap(Vec<u8>); |
| |
| #[cfg(not(target_arch = "wasm32"))] |
| impl Mmap { |
| #[inline] |
| pub unsafe fn map(file: File) -> io::Result<Self> { |
| memmap2::Mmap::map(&file).map(Mmap) |
| } |
| } |
| |
| #[cfg(target_arch = "wasm32")] |
| impl Mmap { |
| #[inline] |
| pub unsafe fn map(mut file: File) -> io::Result<Self> { |
| use std::io::Read; |
| |
| let mut data = Vec::new(); |
| file.read_to_end(&mut data)?; |
| Ok(Mmap(data)) |
| } |
| } |
| |
| impl Deref for Mmap { |
| type Target = [u8]; |
| |
| #[inline] |
| fn deref(&self) -> &[u8] { |
| &*self.0 |
| } |
| } |
| |
| // SAFETY: On architectures other than WASM, mmap is used as backing storage. The address of this |
| // memory map is stable. On WASM, `Vec<u8>` is used as backing storage. The `Mmap` type doesn't |
| // export any function that can cause the `Vec` to be re-allocated. As such the address of the |
| // bytes inside this `Vec` is stable. |
| unsafe impl StableAddress for Mmap {} |