orx_selfref_col/references/
node_ptr.rs

1use crate::{MemoryPolicy, Node, SelfRefCol, Variant};
2use core::fmt::Debug;
3use orx_pinned_vec::PinnedVec;
4
5/// A wrapper around a node pointer.
6pub struct NodePtr<V: Variant> {
7    ptr: *mut Node<V>,
8}
9
10// Despite holding pointer to a Node, `NodePtr` implements `Send` since it does not provide access
11// to the pointer with the safe api. Unsafe api can be used to access the node. Safety of such access
12// can be verified by the `is_valid_for` method.
13unsafe impl<V: Variant> Send for NodePtr<V> where V::Item: Send {}
14
15// Despite holding pointer to a Node, `NodePtr` implements `Sync` since it does not provide access
16// to the pointer with the safe api. Unsafe api can be used to access the node. Safety of such access
17// can be verified by the `is_valid_for` method.
18unsafe impl<V: Variant> Sync for NodePtr<V> where V::Item: Sync {}
19
20impl<V: Variant> PartialEq for NodePtr<V> {
21    fn eq(&self, other: &Self) -> bool {
22        self.ptr == other.ptr
23    }
24}
25
26impl<V: Variant> Debug for NodePtr<V> {
27    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
28        f.debug_struct("NodeIdx")
29            .field("ptr", &(self.ptr as usize))
30            .finish()
31    }
32}
33
34impl<V: Variant> Copy for NodePtr<V> {}
35
36impl<V: Variant> Clone for NodePtr<V> {
37    fn clone(&self) -> Self {
38        *self
39    }
40}
41
42impl<V: Variant> NodePtr<V> {
43    /// Creates a new node pointer by wrapping the given `ptr`.
44    pub fn new(ptr: *const Node<V>) -> Self {
45        Self {
46            ptr: ptr as *mut Node<V>,
47        }
48    }
49
50    /// Returns true if:
51    ///
52    /// * `collection` owns this `NodePtr`, and
53    /// * the node, or corresponding element of the `collection`, that this pointer
54    ///   is pointing at is still active;
55    ///
56    /// false otherwise.
57    ///
58    /// It is safe to use the unsafe methods of `NodePtr` if `is_valid_for(col)`
59    /// returns true where `col` is the collection that the pointer is created from.
60    #[inline(always)]
61    pub fn is_valid_for<M, P>(self, collection: &SelfRefCol<V, M, P>) -> bool
62    where
63        M: MemoryPolicy<V>,
64        P: PinnedVec<Node<V>>,
65    {
66        collection.nodes().contains_ptr(self.ptr) && unsafe { &*self.ptr }.is_active()
67    }
68
69    /// Returns the const raw pointer to the node.
70    ///
71    /// # SAFETY
72    ///
73    /// This method is unsafe as `NodePtr` implements `Send` and `Sync`.
74    ///
75    /// It is safe dereference the received pointer if we know that `is_valid_for(col)` would
76    /// return `true` where `col` is the collection that this pointer is created from.
77    #[inline(always)]
78    pub unsafe fn ptr(self) -> *const Node<V> {
79        self.ptr
80    }
81
82    /// Returns the mutable raw pointer to the node.
83    ///
84    /// # SAFETY
85    ///
86    /// This method is unsafe as `NodePtr` implements `Send` and `Sync`.
87    ///
88    /// It is safe dereference the received pointer if we know that `is_valid_for(col)` would
89    /// return `true` where `col` is the collection that this pointer is created from.
90    #[inline(always)]
91    pub unsafe fn ptr_mut(self) -> *mut Node<V> {
92        self.ptr
93    }
94
95    /// Returns a reference to the node.
96    ///
97    /// # Safety
98    ///
99    /// It is safe to directly access the underlying node if we know that `is_valid_for(col)` would
100    /// return `true` where `col` is the collection that this pointer is created from.
101    #[inline]
102    pub unsafe fn node<'a>(self) -> &'a Node<V> {
103        unsafe { &*self.ptr }
104    }
105
106    /// Returns a mutable reference to the node.
107    ///
108    /// # Safety
109    ///
110    /// It is safe to directly access the underlying node if we know that `is_valid_for(col)` would
111    /// return `true` where `col` is the collection that this pointer is created from.
112    #[inline]
113    #[allow(clippy::mut_from_ref)]
114    pub unsafe fn node_mut<'a>(self) -> &'a mut Node<V> {
115        unsafe { &mut *self.ptr }
116    }
117}
orx_selfref_col/references/node_ptr.rs

orx_selfref_col/references/
node_ptr.rs
