clear out a bunch of old code, reorganize
This commit is contained in:
Pat Hickey
59
crates/memory/src/borrow.rs
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59
crates/memory/src/borrow.rs
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@@ -0,0 +1,59 @@
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use crate::region::Region;
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pub struct GuestBorrows {
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immutable: Vec<Region>,
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mutable: Vec<Region>,
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}
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impl GuestBorrows {
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pub fn new() -> Self {
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GuestBorrows {
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immutable: Vec::new(),
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mutable: Vec::new(),
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}
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}
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fn is_borrowed_immut(&self, r: Region) -> bool {
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!self.immutable.iter().all(|b| !b.overlaps(r))
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}
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fn is_borrowed_mut(&self, r: Region) -> bool {
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!self.mutable.iter().all(|b| !b.overlaps(r))
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}
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pub fn borrow_immut(&mut self, r: Region) -> bool {
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if self.is_borrowed_mut(r) {
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return false;
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}
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self.immutable.push(r);
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true
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}
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pub fn unborrow_immut(&mut self, r: Region) {
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let (ix, _) = self
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.immutable
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.iter()
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.enumerate()
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.find(|(_, reg)| r == **reg)
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.expect("region exists in borrows");
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self.immutable.remove(ix);
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}
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pub fn borrow_mut(&mut self, r: Region) -> bool {
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if self.is_borrowed_immut(r) || self.is_borrowed_mut(r) {
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return false;
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}
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self.mutable.push(r);
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true
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}
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pub fn unborrow_mut(&mut self, r: Region) {
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let (ix, _) = self
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.mutable
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.iter()
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.enumerate()
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.find(|(_, reg)| r == **reg)
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.expect("region exists in borrows");
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self.mutable.remove(ix);
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}
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}
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75
crates/memory/src/guest_type.rs
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75
crates/memory/src/guest_type.rs
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@@ -0,0 +1,75 @@
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pub trait GuestType {
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fn len() -> u32;
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}
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impl GuestType for u8 {
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fn len() -> u32 {
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1
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}
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}
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impl GuestType for i8 {
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fn len() -> u32 {
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1
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}
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}
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impl GuestType for u16 {
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fn len() -> u32 {
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2
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}
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}
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impl GuestType for i16 {
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fn len() -> u32 {
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2
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}
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}
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impl GuestType for u32 {
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fn len() -> u32 {
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4
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}
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}
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impl GuestType for i32 {
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fn len() -> u32 {
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4
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}
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}
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impl GuestType for f32 {
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fn len() -> u32 {
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4
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}
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}
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impl GuestType for u64 {
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fn len() -> u32 {
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8
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}
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}
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impl GuestType for i64 {
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fn len() -> u32 {
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8
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}
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}
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impl GuestType for f64 {
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fn len() -> u32 {
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8
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}
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}
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impl GuestType for char {
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fn len() -> u32 {
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1
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}
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}
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impl GuestType for usize {
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fn len() -> u32 {
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4
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}
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}
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@@ -1,188 +1,8 @@
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#![allow(dead_code, unused)] // DURING DEVELOPMENT
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mod borrow;
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mod guest_type;
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mod memory;
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mod region;
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use std::cell::RefCell;
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use std::marker::PhantomData;
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use std::rc::Rc;
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use thiserror::Error;
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#[derive(Debug, Copy, Clone, PartialEq, Eq)]
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pub struct Region {
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start: u32,
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len: u32,
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}
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impl Region {
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fn overlaps(&self, rhs: Region) -> bool {
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let self_start = self.start as u64;
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let self_end = self.start as u64 + self.len as u64;
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let rhs_start = rhs.start as u64;
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let rhs_end = rhs.start as u64 + rhs.len as u64;
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// start of rhs inside self:
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if (rhs_start >= self_start && rhs_start < self_end) {
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return true;
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}
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// end of rhs inside self:
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if (rhs_end >= self_start && rhs_end < self_end) {
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return true;
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}
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// start of self inside rhs:
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if (self_start >= rhs_start && self_start < rhs_end) {
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return true;
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}
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// end of self inside rhs: XXX is this redundant? i suspect it is but im too tired
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if (self_end >= rhs_start && self_end < rhs_end) {
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return true;
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}
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false
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}
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}
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struct GuestBorrows {
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immutable: Vec<Region>,
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mutable: Vec<Region>,
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}
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impl GuestBorrows {
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pub fn new() -> Self {
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GuestBorrows {
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immutable: Vec::new(),
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mutable: Vec::new(),
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}
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}
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fn is_borrowed_immut(&self, r: Region) -> bool {
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!self.immutable.iter().all(|b| !b.overlaps(r))
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}
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fn is_borrowed_mut(&self, r: Region) -> bool {
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!self.mutable.iter().all(|b| !b.overlaps(r))
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}
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pub fn borrow_immut(&mut self, r: Region) -> bool {
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if self.is_borrowed_mut(r) {
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return false;
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}
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self.immutable.push(r);
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true
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}
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pub fn unborrow_immut(&mut self, r: Region) {
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let (ix, _) = self
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.immutable
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.iter()
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.enumerate()
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.find(|(_, reg)| r == **reg)
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.expect("region exists in borrows");
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self.immutable.remove(ix);
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}
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pub fn borrow_mut(&mut self, r: Region) -> bool {
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if self.is_borrowed_immut(r) || self.is_borrowed_mut(r) {
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return false;
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}
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self.mutable.push(r);
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true
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}
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pub fn unborrow_mut(&mut self, r: Region) {
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let (ix, _) = self
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.mutable
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.iter()
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.enumerate()
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.find(|(_, reg)| r == **reg)
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.expect("region exists in borrows");
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self.mutable.remove(ix);
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}
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}
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pub struct GuestMemory<'a> {
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ptr: *mut u8,
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len: u32,
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lifetime: PhantomData<&'a ()>,
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borrows: Rc<RefCell<GuestBorrows>>,
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}
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impl<'a> GuestMemory<'a> {
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pub fn new(ptr: *mut u8, len: u32) -> GuestMemory<'a> {
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GuestMemory {
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ptr,
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len,
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lifetime: PhantomData,
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borrows: Rc::new(RefCell::new(GuestBorrows::new())),
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}
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}
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fn contains(&self, r: Region) -> bool {
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r.start < self.len
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&& r.len < self.len // make sure next clause doesnt underflow
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&& r.start < (self.len - r.len)
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}
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pub fn ptr(&'a self, r: Region) -> Result<Option<GuestPtr<'a>>, MemoryError> {
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let mut borrows = self.borrows.borrow_mut();
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if !self.contains(r) {
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Err(MemoryError::OutOfBounds)?;
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}
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if borrows.borrow_immut(r) {
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Ok(Some(GuestPtr {
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mem: &self,
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region: r,
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}))
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} else {
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Ok(None)
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}
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}
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pub fn ptr_mut(&'a self, r: Region) -> Result<Option<GuestPtrMut<'a>>, MemoryError> {
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let mut borrows = self.borrows.borrow_mut();
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if !self.contains(r) {
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Err(MemoryError::OutOfBounds)?;
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}
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if borrows.borrow_immut(r) {
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Ok(Some(GuestPtrMut {
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mem: &self,
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region: r,
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}))
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} else {
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Ok(None)
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}
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}
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}
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pub struct GuestPtr<'a> {
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mem: &'a GuestMemory<'a>,
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region: Region,
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}
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impl<'a> Drop for GuestPtr<'a> {
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fn drop(&mut self) {
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let mut borrows = self.mem.borrows.borrow_mut();
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borrows.unborrow_immut(self.region);
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}
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}
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pub struct GuestPtrMut<'a> {
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mem: &'a GuestMemory<'a>,
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region: Region,
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}
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impl<'a> Drop for GuestPtrMut<'a> {
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fn drop(&mut self) {
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let mut borrows = self.mem.borrows.borrow_mut();
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borrows.unborrow_mut(self.region);
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}
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}
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#[derive(Debug, Error)]
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pub enum MemoryError {
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#[error("Out of bounds")]
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OutOfBounds,
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}
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pub use guest_type::GuestType;
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pub use memory::{GuestMemory, GuestPtr, GuestPtrMut};
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pub use region::Region;
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117
crates/memory/src/memory.rs
Normal file
117
crates/memory/src/memory.rs
Normal file
@@ -0,0 +1,117 @@
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use std::cell::RefCell;
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use std::marker::PhantomData;
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use std::rc::Rc;
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use thiserror::Error;
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use crate::borrow::GuestBorrows;
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use crate::guest_type::GuestType;
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use crate::region::Region;
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pub struct GuestMemory<'a> {
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ptr: *mut u8,
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len: u32,
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lifetime: PhantomData<&'a ()>,
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borrows: Rc<RefCell<GuestBorrows>>,
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}
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impl<'a> GuestMemory<'a> {
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pub fn new(ptr: *mut u8, len: u32) -> GuestMemory<'a> {
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GuestMemory {
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ptr,
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len,
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lifetime: PhantomData,
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borrows: Rc::new(RefCell::new(GuestBorrows::new())),
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}
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}
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fn contains(&self, r: Region) -> bool {
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r.start < self.len
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&& r.len < self.len // make sure next clause doesnt underflow
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&& r.start < (self.len - r.len)
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}
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pub fn ptr<T: GuestType>(&'a self, at: u32) -> Result<GuestPtr<'a, T>, MemoryError> {
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let r = Region {
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start: at,
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len: T::len(),
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};
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let mut borrows = self.borrows.borrow_mut();
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if !self.contains(r) {
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Err(MemoryError::OutOfBounds(r))?;
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}
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if borrows.borrow_immut(r) {
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Ok(GuestPtr {
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mem: &self,
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region: r,
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type_: PhantomData,
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})
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} else {
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Err(MemoryError::Borrowed(r))
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}
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}
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pub fn ptr_mut<T: GuestType>(&'a self, at: u32) -> Result<GuestPtrMut<'a, T>, MemoryError> {
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let r = Region {
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start: at,
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len: T::len(),
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};
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let mut borrows = self.borrows.borrow_mut();
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if !self.contains(r) {
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Err(MemoryError::OutOfBounds(r))?;
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}
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if borrows.borrow_mut(r) {
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Ok(GuestPtrMut {
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mem: &self,
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region: r,
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type_: PhantomData,
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})
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} else {
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Err(MemoryError::Borrowed(r))
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}
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}
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}
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pub struct GuestPtr<'a, T> {
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mem: &'a GuestMemory<'a>,
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region: Region,
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type_: PhantomData<T>,
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}
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impl<'a, T> GuestPtr<'a, T> {
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pub fn ptr(&self) -> *const u8 {
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(self.mem.ptr as usize + self.region.start as usize) as *const u8
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}
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}
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impl<'a, T> Drop for GuestPtr<'a, T> {
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fn drop(&mut self) {
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let mut borrows = self.mem.borrows.borrow_mut();
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borrows.unborrow_immut(self.region);
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}
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}
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pub struct GuestPtrMut<'a, T> {
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mem: &'a GuestMemory<'a>,
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region: Region,
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type_: PhantomData<T>,
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}
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impl<'a, T> GuestPtrMut<'a, T> {
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pub fn ptr_mut(&self) -> *mut u8 {
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(self.mem.ptr as usize + self.region.start as usize) as *mut u8
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}
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}
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impl<'a, T> Drop for GuestPtrMut<'a, T> {
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fn drop(&mut self) {
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let mut borrows = self.mem.borrows.borrow_mut();
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borrows.unborrow_mut(self.region);
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}
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}
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#[derive(Debug, Error)]
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pub enum MemoryError {
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#[error("Out of bounds: {0:?}")]
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OutOfBounds(Region),
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#[error("Borrowed: {0:?}")]
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Borrowed(Region),
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}
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37
crates/memory/src/region.rs
Normal file
37
crates/memory/src/region.rs
Normal file
@@ -0,0 +1,37 @@
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#[derive(Debug, Copy, Clone, PartialEq, Eq)]
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pub struct Region {
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pub start: u32,
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pub len: u32,
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}
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impl Region {
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pub fn overlaps(&self, rhs: Region) -> bool {
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let self_start = self.start as u64;
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let self_end = self.start as u64 + self.len as u64;
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let rhs_start = rhs.start as u64;
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let rhs_end = rhs.start as u64 + rhs.len as u64;
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// start of rhs inside self:
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if rhs_start >= self_start && rhs_start < self_end {
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return true;
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}
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// end of rhs inside self:
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if rhs_end >= self_start && rhs_end < self_end {
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return true;
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}
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// start of self inside rhs:
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if self_start >= rhs_start && self_start < rhs_end {
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return true;
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}
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|
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// end of self inside rhs: XXX is this redundant? i suspect it is but im too tired
|
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if self_end >= rhs_start && self_end < rhs_end {
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return true;
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}
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|
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false
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}
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}
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Reference in New Issue
Block a user