lockfree_object_pool/
linear_owned_reusable.rs

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1use crate::linear_object_pool::LinearObjectPool;
2use crate::page::{Page, PageId};
3use std::ops::{Deref, DerefMut};
4use std::sync::Arc;
5
6/// Wrapper over T used by [`LinearObjectPool`].
7///
8/// Access is allowed with [`std::ops::Deref`] or [`std::ops::DerefMut`]
9/// # Example
10/// ```rust
11///  use lockfree_object_pool::LinearObjectPool;
12///  use std::sync::Arc;
13///
14///  let pool = Arc::new(LinearObjectPool::<u32>::new(
15///    ||  Default::default(),
16///    |v| {
17///      *v = 0;
18///    }
19///  ));
20///  let mut item = pool.pull_owned();
21///
22///  *item = 5;
23///  let work = *item * 5;
24/// ```
25pub struct LinearOwnedReusable<T> {
26    pool: Arc<LinearObjectPool<T>>,
27    page_id: PageId,
28    page: *const Page<T>,
29}
30
31impl<T> LinearOwnedReusable<T> {
32    /// Create new element
33    ///
34    /// # Arguments
35    /// * `pool` object pool owner
36    /// * `page_id` page id
37    /// * `page`    page that contains data
38    /// # Safety
39    /// * `page` has to be a valid pointer to a page in `pool`
40    /// * `pool_id` has to be a valid id for `page`
41    #[inline]
42    pub(crate) unsafe fn new(
43        pool: Arc<LinearObjectPool<T>>,
44        page_id: PageId,
45        page: &Page<T>,
46    ) -> Self {
47        Self {
48            pool,
49            page_id,
50            page,
51        }
52    }
53}
54
55impl<T> DerefMut for LinearOwnedReusable<T> {
56    #[inline]
57    fn deref_mut(&mut self) -> &mut Self::Target {
58        unsafe {
59            // SAFETY: there exists only this `LinearOwnedReusable` with this page_id
60            self.page.as_ref().unwrap().get_mut(&self.page_id)
61        }
62    }
63}
64
65impl<T> Deref for LinearOwnedReusable<T> {
66    type Target = T;
67
68    #[inline]
69    fn deref(&self) -> &Self::Target {
70        unsafe {
71            // SAFETY: there exists only this `LinearOwnedReusable` with this page_id
72            self.page.as_ref().unwrap().get(&self.page_id)
73        }
74    }
75}
76
77impl<T> Drop for LinearOwnedReusable<T> {
78    #[inline]
79    fn drop(&mut self) {
80        unsafe {
81            // SAFETY: there exists only this `LinearOwnedReusable` with this page_id
82            let page = self.page.as_ref().unwrap();
83            (self.pool.get_reset_callback())(page.get_mut(&self.page_id));
84            page.free(&self.page_id);
85        }
86    }
87}
88
89unsafe impl<T: Send> Send for LinearOwnedReusable<T> {} // SAFETY: sending the data is allowed if it's Send
90unsafe impl<T: Send> Sync for LinearOwnedReusable<T> {} // SAFETY: the Mutex manages synchronization so only Send is required
lockfree_object_pool/linear_owned_reusable.rs

lockfree_object_pool/
linear_owned_reusable.rs
