#![doc = include_str!("../README.md")]
mod base_vec;
pub mod btreemap;
pub mod cell;
pub use cell::{Cell as StableCell, Cell};
pub mod file_mem;
#[cfg(target_arch = "wasm32")]
mod ic0_memory; pub mod log;
pub use log::{Log as StableLog, Log};
pub mod memory_manager;
pub mod min_heap;
pub mod reader;
pub mod storable;
#[cfg(test)]
mod tests;
mod types;
pub mod vec;
pub use min_heap::{MinHeap, MinHeap as StableMinHeap};
pub use vec::{Vec as StableVec, Vec};
pub mod vec_mem;
pub mod writer;
pub use btreemap::{BTreeMap, BTreeMap as StableBTreeMap};
pub use file_mem::FileMemory;
#[cfg(target_arch = "wasm32")]
pub use ic0_memory::Ic0StableMemory;
use std::error;
use std::fmt::{Display, Formatter};
pub use storable::Storable;
use types::Address;
pub use vec_mem::VectorMemory;
#[cfg(target_arch = "wasm32")]
pub type DefaultMemoryImpl = Ic0StableMemory;
#[cfg(not(target_arch = "wasm32"))]
pub type DefaultMemoryImpl = VectorMemory;
const WASM_PAGE_SIZE: u64 = 65536;
pub const MAX_PAGES: u64 = u64::MAX / WASM_PAGE_SIZE;
pub trait Memory {
fn size(&self) -> u64;
fn grow(&self, pages: u64) -> i64;
fn read(&self, offset: u64, dst: &mut [u8]);
fn write(&self, offset: u64, src: &[u8]);
}
fn read_u32<M: Memory>(m: &M, addr: Address) -> u32 {
let mut buf: [u8; 4] = [0; 4];
m.read(addr.get(), &mut buf);
u32::from_le_bytes(buf)
}
fn read_u64<M: Memory>(m: &M, addr: Address) -> u64 {
let mut buf: [u8; 8] = [0; 8];
m.read(addr.get(), &mut buf);
u64::from_le_bytes(buf)
}
fn write_u32<M: Memory>(m: &M, addr: Address, val: u32) {
write(m, addr.get(), &val.to_le_bytes());
}
fn write_u64<M: Memory>(m: &M, addr: Address, val: u64) {
write(m, addr.get(), &val.to_le_bytes());
}
#[derive(Debug, PartialEq, Eq)]
pub struct GrowFailed {
current_size: u64,
delta: u64,
}
impl Display for GrowFailed {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(
f,
"Failed to grow memory: current size={}, delta={}",
self.current_size,
self.delta
)
}
}
impl error::Error for GrowFailed {}
fn safe_write<M: Memory>(memory: &M, offset: u64, bytes: &[u8]) -> Result<(), GrowFailed> {
let last_byte = offset
.checked_add(bytes.len() as u64)
.expect("Address space overflow");
let size_pages = memory.size();
let size_bytes = size_pages
.checked_mul(WASM_PAGE_SIZE)
.expect("Address space overflow");
if size_bytes < last_byte {
let diff_bytes = last_byte - size_bytes;
let diff_pages = diff_bytes
.checked_add(WASM_PAGE_SIZE - 1)
.expect("Address space overflow")
/ WASM_PAGE_SIZE;
if memory.grow(diff_pages) == -1 {
return Err(GrowFailed {
current_size: size_pages,
delta: diff_pages,
});
}
}
memory.write(offset, bytes);
Ok(())
}
fn write<M: Memory>(memory: &M, offset: u64, bytes: &[u8]) {
if let Err(GrowFailed {
current_size,
delta,
}) = safe_write(memory, offset, bytes)
{
panic!(
"Failed to grow memory from {} pages to {} pages (delta = {} pages).",
current_size,
current_size + delta,
delta
);
}
}
fn read_struct<T, M: Memory>(addr: Address, memory: &M) -> T {
let mut t: T = unsafe { core::mem::zeroed() };
let t_slice = unsafe {
core::slice::from_raw_parts_mut(&mut t as *mut _ as *mut u8, core::mem::size_of::<T>())
};
memory.read(addr.get(), t_slice);
t
}
fn write_struct<T, M: Memory>(t: &T, addr: Address, memory: &M) {
let slice = unsafe {
core::slice::from_raw_parts(t as *const _ as *const u8, core::mem::size_of::<T>())
};
write(memory, addr.get(), slice)
}
#[derive(Clone)]
pub struct RestrictedMemory<M: Memory> {
page_range: core::ops::Range<u64>,
memory: M,
}
impl<M: Memory> RestrictedMemory<M> {
pub fn new(memory: M, page_range: core::ops::Range<u64>) -> Self {
assert!(page_range.end <= MAX_PAGES);
Self { memory, page_range }
}
}
impl<M: Memory> Memory for RestrictedMemory<M> {
fn size(&self) -> u64 {
let base_size = self.memory.size();
if base_size < self.page_range.start {
0
} else if base_size > self.page_range.end {
self.page_range.end - self.page_range.start
} else {
base_size - self.page_range.start
}
}
fn grow(&self, delta: u64) -> i64 {
let base_size = self.memory.size();
if base_size < self.page_range.start {
self.memory
.grow(self.page_range.start - base_size + delta)
.min(0)
} else if base_size >= self.page_range.end {
if delta == 0 {
(self.page_range.end - self.page_range.start) as i64
} else {
-1
}
} else {
let pages_left = self.page_range.end - base_size;
if pages_left < delta {
-1
} else {
let r = self.memory.grow(delta);
if r < 0 {
r
} else {
r - self.page_range.start as i64
}
}
}
}
fn read(&self, offset: u64, dst: &mut [u8]) {
self.memory
.read(self.page_range.start * WASM_PAGE_SIZE + offset, dst)
}
fn write(&self, offset: u64, src: &[u8]) {
self.memory
.write(self.page_range.start * WASM_PAGE_SIZE + offset, src)
}
}