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|
#[cfg(target_arch = "wasm32")]
use core::arch::wasm32 as wasm;
#[cfg(target_arch = "wasm64")]
use core::arch::wasm64 as wasm;
use core::ptr;
use Allocator;
/// System setting for Wasm
pub struct System {
_priv: (),
}
impl System {
pub const fn new() -> System {
System { _priv: () }
}
}
unsafe impl Allocator for System {
fn alloc(&self, size: usize) -> (*mut u8, usize, u32) {
let pages = size / self.page_size();
let prev = wasm::memory_grow(0, pages);
if prev == usize::max_value() {
return (ptr::null_mut(), 0, 0);
}
(
(prev * self.page_size()) as *mut u8,
pages * self.page_size(),
0,
)
}
fn remap(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize, _can_move: bool) -> *mut u8 {
// TODO: I think this can be implemented near the end?
ptr::null_mut()
}
fn free_part(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize) -> bool {
false
}
fn free(&self, _ptr: *mut u8, _size: usize) -> bool {
false
}
fn can_release_part(&self, _flags: u32) -> bool {
false
}
fn allocates_zeros(&self) -> bool {
true
}
fn page_size(&self) -> usize {
64 * 1024
}
}
#[cfg(feature = "global")]
pub fn acquire_global_lock() {
// single threaded, no need!
}
#[cfg(feature = "global")]
pub fn release_global_lock() {
// single threaded, no need!
}
#[cfg(feature = "global")]
pub unsafe fn enable_alloc_after_fork() {
// single threaded, no need!
}
|
