mirror of
https://github.com/fluencelabs/wasmer
synced 2024-12-15 23:25:41 +00:00
121 lines
3.3 KiB
Rust
121 lines
3.3 KiB
Rust
use std::{cell::Cell, fmt, marker::PhantomData, mem};
|
|
use wasmer_runtime_core::{
|
|
memory::Memory,
|
|
types::{ValueType, WasmExternType},
|
|
};
|
|
|
|
pub struct Array;
|
|
pub struct Item;
|
|
|
|
// TODO: before shipping, refactor this and the wasi code into a common crate
|
|
// and wrap it when used in the context of wasi to return the proper error codes
|
|
|
|
#[repr(transparent)]
|
|
pub struct WasmPtr<T: Copy, Ty = Item> {
|
|
offset: u32,
|
|
_phantom: PhantomData<(T, Ty)>,
|
|
}
|
|
|
|
impl<T: Copy, Ty> WasmPtr<T, Ty> {
|
|
#[inline]
|
|
pub fn new(offset: u32) -> Self {
|
|
Self {
|
|
offset,
|
|
_phantom: PhantomData,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn offset(self) -> i32 {
|
|
self.offset as i32
|
|
}
|
|
}
|
|
|
|
#[inline(always)]
|
|
fn align_pointer(ptr: usize, align: usize) -> usize {
|
|
// clears bits below aligment amount (assumes power of 2) to align pointer
|
|
debug_assert!(align.count_ones() == 1);
|
|
ptr & !(align - 1)
|
|
}
|
|
|
|
impl<T: Copy + ValueType> WasmPtr<T, Item> {
|
|
#[inline]
|
|
pub fn deref<'a>(self, memory: &'a Memory) -> Option<&'a Cell<T>> {
|
|
if (self.offset as usize) + mem::size_of::<T>() >= memory.size().bytes().0 {
|
|
return None;
|
|
}
|
|
unsafe {
|
|
let cell_ptr = align_pointer(
|
|
memory.view::<u8>().as_ptr().add(self.offset as usize) as usize,
|
|
mem::align_of::<T>(),
|
|
) as *const Cell<T>;
|
|
Some(&*cell_ptr)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T: Copy + ValueType> WasmPtr<T, Array> {
|
|
#[inline]
|
|
pub fn deref<'a>(self, memory: &'a Memory, index: u32, length: u32) -> Option<&'a [Cell<T>]> {
|
|
// gets the size of the item in the array with padding added such that
|
|
// for any index, we will always result an aligned memory access
|
|
let item_size = mem::size_of::<T>() + (mem::size_of::<T>() % mem::align_of::<T>());
|
|
let slice_full_len = index as usize + length as usize;
|
|
|
|
if (self.offset as usize) + (item_size * slice_full_len) >= memory.size().bytes().0 {
|
|
return None;
|
|
}
|
|
|
|
unsafe {
|
|
let cell_ptr = align_pointer(
|
|
memory.view::<u8>().as_ptr().add(self.offset as usize) as usize,
|
|
mem::align_of::<T>(),
|
|
) as *const Cell<T>;
|
|
let cell_ptrs = &std::slice::from_raw_parts(cell_ptr, slice_full_len)
|
|
[index as usize..slice_full_len as usize];
|
|
Some(cell_ptrs)
|
|
}
|
|
}
|
|
}
|
|
|
|
unsafe impl<T: Copy, Ty> WasmExternType for WasmPtr<T, Ty> {
|
|
type Native = i32;
|
|
|
|
fn to_native(self) -> Self::Native {
|
|
self.offset as i32
|
|
}
|
|
fn from_native(n: Self::Native) -> Self {
|
|
Self {
|
|
offset: n as u32,
|
|
_phantom: PhantomData,
|
|
}
|
|
}
|
|
}
|
|
|
|
unsafe impl<T: Copy, Ty> ValueType for WasmPtr<T, Ty> {}
|
|
|
|
impl<T: Copy, Ty> Clone for WasmPtr<T, Ty> {
|
|
fn clone(&self) -> Self {
|
|
Self {
|
|
offset: self.offset,
|
|
_phantom: PhantomData,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T: Copy, Ty> Copy for WasmPtr<T, Ty> {}
|
|
|
|
impl<T: Copy, Ty> PartialEq for WasmPtr<T, Ty> {
|
|
fn eq(&self, other: &Self) -> bool {
|
|
self.offset == other.offset
|
|
}
|
|
}
|
|
|
|
impl<T: Copy, Ty> Eq for WasmPtr<T, Ty> {}
|
|
|
|
impl<T: Copy, Ty> fmt::Debug for WasmPtr<T, Ty> {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
write!(f, "WasmPtr({:#x})", self.offset)
|
|
}
|
|
}
|