linera_witty/runtime/wasmer/
memory.rs

1// Copyright (c) Zefchain Labs, Inc.
2// SPDX-License-Identifier: Apache-2.0
3
4//! How to access the memory of a Wasmer guest instance.
5
6use std::borrow::Cow;
7
8use wasmer::{Extern, Memory};
9
10use super::{super::traits::InstanceWithMemory, EntrypointInstance, ReentrantInstance};
11use crate::{GuestPointer, RuntimeError, RuntimeMemory};
12
13macro_rules! impl_memory_traits {
14    ($instance:ty) => {
15        impl<UserData: 'static> InstanceWithMemory for $instance {
16            fn memory_from_export(&self, export: Extern) -> Result<Option<Memory>, RuntimeError> {
17                Ok(match export {
18                    Extern::Memory(memory) => Some(memory),
19                    _ => None,
20                })
21            }
22        }
23
24        impl<UserData: 'static> RuntimeMemory<$instance> for Memory {
25            fn read<'instance>(
26                &self,
27                instance: &'instance $instance,
28                location: GuestPointer,
29                length: u32,
30            ) -> Result<Cow<'instance, [u8]>, RuntimeError> {
31                let mut buffer = vec![0u8; length as usize];
32                let start = location.0 as u64;
33
34                self.view(instance).read(start, &mut buffer)?;
35
36                Ok(Cow::Owned(buffer))
37            }
38
39            fn write(
40                &mut self,
41                instance: &mut $instance,
42                location: GuestPointer,
43                bytes: &[u8],
44            ) -> Result<(), RuntimeError> {
45                let start = location.0 as u64;
46
47                self.view(&*instance).write(start, bytes)?;
48
49                Ok(())
50            }
51        }
52    };
53}
54
55impl_memory_traits!(EntrypointInstance<UserData>);
56impl_memory_traits!(ReentrantInstance<'_, UserData>);
linera_witty/runtime/wasmer/memory.rs

linera_witty/runtime/wasmer/
memory.rs
