openthread/ot/singleton/
backing.rs

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1// Copyright 2022 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use super::*;
6use std::cell::{Cell, RefCell};
7use std::task::Waker;
8
9/// Backing struct for OpenThread instances. This type contains information
10/// related to the rust API implementation.
11#[allow(clippy::type_complexity)]
12pub(crate) struct InstanceBacking {
13    pub waker: Cell<Waker>,
14    pub platform: RefCell<std::boxed::Box<dyn Platform>>,
15    pub state_change_fn: Cell<Option<std::boxed::Box<dyn FnMut(ot::ChangedFlags)>>>,
16    pub cli_output_fn: Cell<Option<std::boxed::Box<dyn FnMut(&CStr)>>>,
17    pub ip6_receive_fn: Cell<Option<std::boxed::Box<dyn FnMut(OtMessageBox<'_>)>>>,
18    pub ip6_address_fn: Cell<Option<std::boxed::Box<dyn FnMut(Ip6AddressInfo<'_>, bool)>>>,
19    pub multicast_listener_callback:
20        Cell<Option<std::boxed::Box<dyn FnMut(BackboneRouterMulticastListenerEvent, &Ip6Address)>>>,
21    pub active_scan_fn: Cell<Option<std::boxed::Box<dyn FnMut(Option<&ActiveScanResult>)>>>,
22    pub energy_scan_fn: Cell<Option<std::boxed::Box<dyn FnMut(Option<&EnergyScanResult>)>>>,
23    pub joiner_fn: Cell<Option<std::boxed::Box<dyn FnOnce(Result)>>>,
24    pub srp_server_service_update_fn: Cell<
25        Option<std::boxed::Box<dyn FnMut(ot::SrpServerServiceUpdateId, &ot::SrpServerHost, u32)>>,
26    >,
27    pub dnssd_query_sub_unsub_fn: Cell<Option<std::boxed::Box<dyn FnMut(bool, &CStr)>>>,
28    pub nat64_receive_fn: Cell<Option<std::boxed::Box<dyn FnMut(OtMessageBox<'_>)>>>,
29    pub dhcp6pd_state_change_callback_fn:
30        Cell<Option<std::boxed::Box<dyn FnMut(BorderRoutingDhcp6PdState)>>>,
31}
32
33impl InstanceBacking {
34    pub(crate) fn new<T: Platform + 'static>(platform: T) -> Self {
35        Self {
36            waker: Cell::new(futures::task::noop_waker()),
37            platform: RefCell::new(Box::new(platform) as std::boxed::Box<dyn Platform>),
38            cli_output_fn: Cell::new(None),
39            ip6_receive_fn: Cell::new(None),
40            ip6_address_fn: Cell::new(None),
41            state_change_fn: Cell::new(None),
42            active_scan_fn: Cell::new(None),
43            energy_scan_fn: Cell::new(None),
44            joiner_fn: Cell::new(None),
45            srp_server_service_update_fn: Cell::new(None),
46            dnssd_query_sub_unsub_fn: Cell::new(None),
47            multicast_listener_callback: Cell::new(None),
48            nat64_receive_fn: Cell::new(None),
49            dhcp6pd_state_change_callback_fn: Cell::new(None),
50        }
51    }
52}
53
54impl InstanceBacking {
55    unsafe fn glob() -> &'static mut Option<InstanceBacking> {
56        static mut SINGLETON_BACKING: Option<InstanceBacking> = None;
57        // TODO(b/319328255) -- Fix usage so lint no longer applies
58        #[allow(static_mut_refs)]
59        &mut SINGLETON_BACKING
60    }
61
62    /// Returns a reference to the global singleton `InstanceBacking`.
63    ///
64    /// If you are tempted to use this method, consider using `Instance::borrow_backing()`
65    /// instead.
66    ///
67    /// ## Safety ##
68    ///
69    /// The behavior of this method is undefined when called at the same
70    /// time that `InstanceBacking::set_singleton()`/`InstanceBacking::drop_singleton()`
71    /// is being called from a different thread.
72    ///
73    /// In order to keep things safe and straightforward, this method should
74    /// only be called by the implementation of `Instance::borrow_backing()`.
75    pub(crate) unsafe fn as_ref() -> &'static InstanceBacking {
76        Self::glob().as_ref().expect("otInstance is uninitialized")
77    }
78
79    /// Initializes the singleton instance backing with the given value.
80    /// Will panic if this is called twice without calling
81    /// `InstanceBacking::finalize` in between.
82    ///
83    /// ## Safety ##
84    ///
85    /// The behavior of this method is undefined when called at the same
86    /// time that `InstanceBacking::as_ref()`/`InstanceBacking::drop_singleton()`
87    /// is being called from a different thread.
88    ///
89    /// In order to keep things safe and straightforward, this method should
90    /// only be called by the implementation of `Instance::new()`.
91    pub(crate) unsafe fn set_singleton(backing: InstanceBacking) {
92        trace!("Setting Singleton InstanceBacking");
93        assert!(Self::glob().replace(backing).is_none(), "Tried to make two OpenThread instances");
94    }
95
96    /// Finalizes and drops the singleton instance backing. After this
97    /// method is called, [`InstacnceBacking::set`] may be called again.
98    ///
99    /// ## Safety ##
100    ///
101    /// The behavior of this method is undefined when called at the same
102    /// time that `InstanceBacking::set_singleton()`/`InstanceBacking::as_ref()`
103    /// is being called from a different thread.
104    ///
105    /// In order to keep things safe and straightforward, this method should
106    /// only be called by the implementation of `Instance::finalize()`.
107    pub(crate) unsafe fn drop_singleton() {
108        trace!("Dropping Singleton InstanceBacking");
109        assert!(Self::glob().take().is_some(), "Tried to drop singleton that was never allocated");
110    }
111}
openthread/ot/singleton/backing.rs

openthread/ot/singleton/
backing.rs
