blink-alloc 0.4.0

Fast, concurrent, arena-based allocator with drop support
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139

use super::*;

with_cursor!(AtomicPtr<u8>);

struct Inner {
    root: Option<NonNull<ChunkHeader>>,
    min_chunk_size: usize,
}

unsafe impl Send for Inner {}
unsafe impl Sync for Inner {}

/// Multi-threaded arena allocator.
pub struct ArenaSync {
    inner: RwLock<Inner>,
}

impl Drop for ArenaSync {
    #[inline(always)]
    fn drop(&mut self) {
        debug_assert!(
            self.inner.get_mut().root.is_none(),
            "Owner must reset `ArenaSync` with `keep_last` set to `false` before drop"
        );
    }
}

impl ArenaSync {
    #[inline(always)]
    pub const fn new() -> Self {
        ArenaSync {
            inner: RwLock::new(Inner {
                root: None,
                min_chunk_size: CHUNK_START_SIZE,
            }),
        }
    }

    #[inline(always)]
    pub const fn with_chunk_size(min_chunk_size: usize) -> Self {
        ArenaSync {
            inner: RwLock::new(Inner {
                root: None,
                min_chunk_size,
            }),
        }
    }

    #[inline(always)]
    pub unsafe fn alloc_fast(&self, layout: Layout) -> Option<NonNull<[u8]>> {
        let inner = self.inner.read();

        if let Some(root) = inner.root {
            return unsafe { ChunkHeader::alloc(root, layout) };
        }

        None
    }

    #[inline(always)]
    pub unsafe fn alloc_slow(
        &self,
        layout: Layout,
        allocator: impl Allocator,
    ) -> Result<NonNull<[u8]>, AllocError> {
        let mut guard = self.inner.write();
        let inner = &mut *guard;

        alloc_slow(
            Cell::from_mut(&mut inner.root),
            inner.min_chunk_size,
            layout,
            &allocator,
        )
    }

    #[inline(always)]
    pub unsafe fn resize_fast(
        &self,
        ptr: NonNull<u8>,
        old_layout: Layout,
        new_layout: Layout,
    ) -> Option<NonNull<[u8]>> {
        let inner = self.inner.read();

        if let Some(root) = inner.root {
            return unsafe { ChunkHeader::resize(root, ptr, old_layout, new_layout) };
        }
        None
    }

    #[inline(always)]
    pub unsafe fn resize_slow(
        &self,
        ptr: NonNull<u8>,
        old_layout: Layout,
        new_layout: Layout,
        allocator: impl Allocator,
    ) -> Result<NonNull<[u8]>, AllocError> {
        let mut guard = self.inner.write();
        let inner = &mut *guard;

        resize_slow(
            Cell::from_mut(&mut inner.root),
            inner.min_chunk_size,
            ptr,
            old_layout,
            new_layout,
            &allocator,
        )
    }

    #[inline(always)]
    pub unsafe fn dealloc(&self, ptr: NonNull<u8>, size: usize) {
        dealloc(self.inner.read().root, ptr, size)
    }

    #[inline(always)]
    pub unsafe fn reset(&mut self, keep_last: bool, allocator: impl Allocator) {
        unsafe {
            reset(
                Cell::from_mut(&mut self.inner.get_mut().root),
                keep_last,
                allocator,
            )
        }
    }

    #[inline(always)]
    pub unsafe fn reset_unchecked(&self, keep_last: bool, allocator: impl Allocator) {
        let mut guard = self.inner.write();
        unsafe { reset(Cell::from_mut(&mut guard.root), keep_last, allocator) }
    }

    // #[inline(always)]
    // pub fn reset_leak(&mut self, keep_last: bool) {
    //     reset_leak(Cell::from_mut(&mut self.inner.get_mut().root), keep_last)
    // }
}