wgpu_core/lock/
vanilla.rs

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
140
141
142
143
144
145
146
147
148
149
150
151
//! Plain, uninstrumented wrappers around [`parking_lot`] lock types.
//!
//! These definitions are used when no particular lock instrumentation
//! Cargo feature is selected.

use core::{fmt, ops};

use crate::lock::rank::LockRank;

pub struct RankData;

/// A plain wrapper around [`parking_lot::Mutex`].
///
/// This is just like [`parking_lot::Mutex`], except that our [`new`]
/// method takes a rank, indicating where the new mutex should sit in
/// `wgpu-core`'s lock ordering. The rank is ignored.
///
/// See the [`lock`] module documentation for other wrappers.
///
/// [`new`]: Mutex::new
/// [`lock`]: crate::lock
pub struct Mutex<T>(parking_lot::Mutex<T>);

/// A guard produced by locking [`Mutex`].
///
/// This is just a wrapper around a [`parking_lot::MutexGuard`].
pub struct MutexGuard<'a, T>(parking_lot::MutexGuard<'a, T>);

impl<T> Mutex<T> {
    pub fn new(_rank: LockRank, value: T) -> Mutex<T> {
        Mutex(parking_lot::Mutex::new(value))
    }

    pub fn lock(&self) -> MutexGuard<T> {
        MutexGuard(self.0.lock())
    }

    pub fn into_inner(self) -> T {
        self.0.into_inner()
    }
}

impl<'a, T> ops::Deref for MutexGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &Self::Target {
        self.0.deref()
    }
}

impl<'a, T> ops::DerefMut for MutexGuard<'a, T> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        self.0.deref_mut()
    }
}

impl<T: fmt::Debug> fmt::Debug for Mutex<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.0.fmt(f)
    }
}

/// A plain wrapper around [`parking_lot::RwLock`].
///
/// This is just like [`parking_lot::RwLock`], except that our [`new`]
/// method takes a rank, indicating where the new mutex should sit in
/// `wgpu-core`'s lock ordering. The rank is ignored.
///
/// See the [`lock`] module documentation for other wrappers.
///
/// [`new`]: RwLock::new
/// [`lock`]: crate::lock
pub struct RwLock<T>(parking_lot::RwLock<T>);

/// A read guard produced by locking [`RwLock`] as a reader.
///
/// This is just a wrapper around a [`parking_lot::RwLockReadGuard`].
pub struct RwLockReadGuard<'a, T>(parking_lot::RwLockReadGuard<'a, T>);

/// A write guard produced by locking [`RwLock`] as a writer.
///
/// This is just a wrapper around a [`parking_lot::RwLockWriteGuard`].
pub struct RwLockWriteGuard<'a, T>(parking_lot::RwLockWriteGuard<'a, T>);

impl<T> RwLock<T> {
    pub fn new(_rank: LockRank, value: T) -> RwLock<T> {
        RwLock(parking_lot::RwLock::new(value))
    }

    pub fn read(&self) -> RwLockReadGuard<T> {
        RwLockReadGuard(self.0.read())
    }

    pub fn write(&self) -> RwLockWriteGuard<T> {
        RwLockWriteGuard(self.0.write())
    }

    /// Force an read-unlock operation on this lock.
    ///
    /// Safety:
    /// - A read lock must be held which is not held by a guard.
    pub unsafe fn force_unlock_read(&self, _data: RankData) {
        unsafe { self.0.force_unlock_read() };
    }
}

impl<'a, T> RwLockReadGuard<'a, T> {
    // Forget the read guard, leaving the lock in a locked state with no guard.
    //
    // Equivalent to std::mem::forget, but preserves the information about the lock
    // rank.
    pub fn forget(this: Self) -> RankData {
        core::mem::forget(this.0);

        RankData
    }
}

impl<'a, T> RwLockWriteGuard<'a, T> {
    pub fn downgrade(this: Self) -> RwLockReadGuard<'a, T> {
        RwLockReadGuard(parking_lot::RwLockWriteGuard::downgrade(this.0))
    }
}

impl<T: fmt::Debug> fmt::Debug for RwLock<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.0.fmt(f)
    }
}

impl<'a, T> ops::Deref for RwLockReadGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &Self::Target {
        self.0.deref()
    }
}

impl<'a, T> ops::Deref for RwLockWriteGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &Self::Target {
        self.0.deref()
    }
}

impl<'a, T> ops::DerefMut for RwLockWriteGuard<'a, T> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        self.0.deref_mut()
    }
}