T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Revisit GuestArray and their deref mechanics

Browse Source 
In preparation for landing `string` support in `wiggle`, I've
revisited `GuestArray` and the deref mechanics, and decided to
scrap the current approach in favour of the previous. Namely, for
`T: GuestTypeCopy` we provide `GuestArray::as_ref` which then can
be derefed directly to `&[T]` since the guest and host types have
matching representation, and for other types (thinking here of
our infamous arrays of pointers), I've instead added a way to
iterate over the pointers. Then, it is up to the `wiggle`'s client
to know whether they can deref whatever the pointer stored in array
is pointing at.
This commit is contained in:
Jakub Konka
2020-02-20 14:51:22 +01:00
committed by Jakub Konka
parent 2ad77538f5
commit 898af8e2fb
2 changed files with 110 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
tests/main.rs
View File

@@ -1,6 +1,7 @@
use proptest::prelude::*;
use wiggle_runtime::{
GuestError, GuestErrorType, GuestMemory, GuestPtr, GuestPtrMut, GuestRef, GuestRefMut,
GuestArray, GuestError, GuestErrorType, GuestMemory, GuestPtr, GuestPtrMut, GuestRef,
GuestRefMut,
};
wiggle_generate::from_witx!({
@@ -97,25 +98,20 @@ impl foo::Foo for WasiCtx {
&mut self,
excuses: &types::ConstExcuseArray,
) -> Result<types::Excuse, types::Errno> {
let excuses = &*excuses
.as_ref()
.expect("dereferencing GuestArray should succeed");
let last = excuses
.iter()
.last()
.expect("input array is non-empty")
.as_ptr()
.expect("valid ptr to ptr")
.read_ptr_from_guest()
.expect("valid ptr to some Excuse value");
Ok(*last.as_ref().expect("dereferencing ptr should succeed"))
}
fn populate_excuses(&mut self, excuses: &types::ExcuseArray) -> Result<(), types::Errno> {
let excuses = &*excuses
.as_ref()
.expect("dereferencing GuestArray should succeed");
for excuse in excuses {
for excuse in excuses.iter() {
let ptr_to_ptr = excuse
.as_ptr()
.expect("valid ptr to ptr")
.read_ptr_from_guest()
.expect("valid ptr to some Excuse value");
let mut ptr = ptr_to_ptr
@@ -752,19 +748,14 @@ impl PopulateExcusesExcercise {
);
assert_eq!(res, types::Errno::Ok.into(), "populate excuses errno");
let arr = {
let ptr: GuestPtr<'_, GuestPtr<'_, types::Excuse>> = guest_memory
.ptr(self.array_ptr_loc.ptr)
.expect("ptr to the first element of array");
&*ptr
.array(self.elements.len() as u32)
.expect("as array")
.as_ref()
.expect("deref to &[]")
};
for el in arr {
let arr: GuestArray<'_, GuestPtr<'_, types::Excuse>> = guest_memory
.ptr(self.array_ptr_loc.ptr)
.expect("ptr to the first element of array")
.array(self.elements.len() as u32)
.expect("as array");
for el in arr.iter() {
let ptr_to_ptr = el
.as_ptr()
.expect("valid ptr to ptr")
.read_ptr_from_guest()
.expect("valid ptr to some Excuse value");
assert_eq!(