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Add Pages and Bytes newtypes

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This commit is contained in:
Lachlan Sneff
2019-01-29 15:44:15 -08:00
parent bc78738bb7
commit 69e9c5154d
16 changed files with 278 additions and 138 deletions
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59
lib/runtime-core/src/memory/dynamic.rs
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@ -1,7 +1,8 @@
use crate::{
memory::{WASM_MAX_PAGES, WASM_PAGE_SIZE},
error::CreationError,
sys,
types::MemoryDescriptor,
units::{Bytes, Pages},
vm,
};
@ -22,24 +23,24 @@ pub const DYNAMIC_GUARD_SIZE: usize = 4096;
/// us to add a guard-page at the end to help elide some bounds-checks.
pub struct DynamicMemory {
memory: sys::Memory,
current: u32,
max: Option<u32>,
current: Pages,
max: Option<Pages>,
}
impl DynamicMemory {
pub(super) fn new(desc: MemoryDescriptor, local: &mut vm::LocalMemory) -> Option<Box<Self>> {
pub(super) fn new(
desc: MemoryDescriptor,
local: &mut vm::LocalMemory,
) -> Result<Box<Self>, CreationError> {
let min_bytes: Bytes = desc.minimum.into();
let memory = {
let mut memory =
sys::Memory::with_size((desc.minimum as usize * WASM_PAGE_SIZE) + DYNAMIC_GUARD_SIZE)
.ok()?;
if desc.minimum != 0 {
let mut memory = sys::Memory::with_size(min_bytes.0 + DYNAMIC_GUARD_SIZE)
.map_err(|_| CreationError::UnableToCreateMemory)?;
if desc.minimum != Pages(0) {
unsafe {
memory
.protect(
0..(desc.minimum as usize * WASM_PAGE_SIZE),
sys::Protect::ReadWrite,
)
.ok()?;
.protect(0..min_bytes.0, sys::Protect::ReadWrite)
.map_err(|_| CreationError::UnableToCreateMemory)?;
}
}
@ -54,18 +55,18 @@ impl DynamicMemory {
let storage_ptr: *mut DynamicMemory = &mut *storage;
local.base = storage.memory.as_ptr();
local.bound = desc.minimum as usize * WASM_PAGE_SIZE;
local.bound = min_bytes.0;
local.memory = storage_ptr as *mut ();
Some(storage)
Ok(storage)
}
pub fn current(&self) -> u32 {
pub fn size(&self) -> Pages {
self.current
}
pub fn grow(&mut self, delta: u32, local: &mut vm::LocalMemory) -> Option<u32> {
if delta == 0 {
pub fn grow(&mut self, delta: Pages, local: &mut vm::LocalMemory) -> Option<Pages> {
if delta == Pages(0) {
return Some(self.current);
}
@ -77,30 +78,22 @@ impl DynamicMemory {
}
}
if new_pages as usize > WASM_MAX_PAGES {
return None;
}
let mut new_memory =
sys::Memory::with_size((new_pages as usize * WASM_PAGE_SIZE) + DYNAMIC_GUARD_SIZE)
.ok()?;
sys::Memory::with_size(new_pages.bytes().0 + DYNAMIC_GUARD_SIZE).ok()?;
unsafe {
new_memory
.protect(
0..(new_pages as usize * WASM_PAGE_SIZE),
sys::Protect::ReadWrite,
)
.protect(0..new_pages.bytes().0, sys::Protect::ReadWrite)
.ok()?;
new_memory.as_slice_mut()[..self.current as usize * WASM_PAGE_SIZE]
.copy_from_slice(&self.memory.as_slice()[..self.current as usize * WASM_PAGE_SIZE]);
new_memory.as_slice_mut()[..self.current.bytes().0]
.copy_from_slice(&self.memory.as_slice()[..self.current.bytes().0]);
}
self.memory = new_memory; //The old memory gets dropped.
local.base = self.memory.as_ptr();
local.bound = new_pages as usize * WASM_PAGE_SIZE;
local.bound = new_pages.bytes().0;
let old_pages = self.current;
self.current = new_pages;
@ -108,10 +101,10 @@ impl DynamicMemory {
}
pub fn as_slice(&self) -> &[u8] {
unsafe { &self.memory.as_slice()[0..self.current as usize * WASM_PAGE_SIZE] }
unsafe { &self.memory.as_slice()[0..self.current.bytes().0] }
}
pub fn as_slice_mut(&mut self) -> &mut [u8] {
unsafe { &mut self.memory.as_slice_mut()[0..self.current as usize * WASM_PAGE_SIZE] }
unsafe { &mut self.memory.as_slice_mut()[0..self.current.bytes().0] }
}
}