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//
// Copyright (c) 2023 ZettaScale Technology
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License 2.0 which is available at
// http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
//
// Contributors:
// ZettaScale Zenoh Team, <zenoh@zettascale.tech>
//
#![cfg(all(feature = "shared-memory", feature = "unstable"))]
use zenoh::{
bytes::ZBytes,
shm::{zshmmut, PosixShmProviderBackend, ShmProviderBuilder, ZShm, ZShmMut},
Wait,
};
#[test]
fn shm_bytes_single_buf() {
// create an SHM backend...
let backend = PosixShmProviderBackend::builder(4096).wait().unwrap();
// ...and an SHM provider
let provider = ShmProviderBuilder::backend(backend).wait();
// Prepare a layout for allocations
let layout = provider.alloc_layout(1024).unwrap();
// allocate an SHM buffer (ZShmMut)
let owned_shm_buf_mut = layout.alloc().wait().unwrap();
// convert into immutable owned buffer (ZShmMut -> ZSlceShm)
let owned_shm_buf: ZShm = owned_shm_buf_mut.into();
// convert again into mutable owned buffer (ZShm -> ZSlceShmMut)
let owned_shm_buf_mut: ZShmMut = owned_shm_buf.try_into().unwrap();
// build a ZBytes from an SHM buffer (ZShmMut -> ZBytes)
let mut payload: ZBytes = owned_shm_buf_mut.into();
// branch to illustrate immutable access to SHM data
{
// deserialize ZBytes as an immutably borrowed zshm (ZBytes -> &zshm)
let borrowed_shm_buf = payload.as_shm().unwrap();
// construct owned buffer from borrowed type (&zshm -> ZShm)
let owned = borrowed_shm_buf.to_owned();
// try to construct mutable ZShmMut (ZShm -> ZShmMut)
let owned_mut: Result<ZShmMut, _> = owned.try_into();
// the attempt fails because ZShm has two existing references ('owned' and inside 'payload')
assert!(owned_mut.is_err())
}
// branch to illustrate mutable access to SHM data
{
// deserialize ZBytes as mutably borrowed zshm (ZBytes -> &mut zshm)
let borrowed_shm_buf = payload.as_shm_mut().unwrap();
// convert zshm to zshmmut (&mut zshm -> &mut zshmmut)
let _borrowed_shm_buf_mut: &mut zshmmut = borrowed_shm_buf.try_into().unwrap();
}
}