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
|
use crate::read_guard::RwLockReadGuard;
use crate::sys;
use crate::write_guard::RwLockWriteGuard;
use std::io;
/// Advisory reader-writer lock for files.
///
/// This type of lock allows a number of readers or at most one writer at any point
/// in time. The write portion of this lock typically allows modification of the
/// underlying data (exclusive access) and the read portion of this lock typically
/// allows for read-only access (shared access).
#[derive(Debug)]
pub struct RwLock<T: sys::AsRaw> {
lock: sys::RwLock<T>,
}
impl<T: sys::AsRaw> RwLock<T> {
/// Create a new instance.
///
/// # Examples
///
/// ```no_run
/// use fd_lock::RwLock;
/// use std::fs::File;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = RwLock::new(File::open("foo.txt")?);
/// Ok(())
/// }
/// ```
#[inline]
pub fn new(inner: T) -> Self {
Self {
lock: sys::RwLock::new(inner),
}
}
/// Locks this lock with shared read access, blocking the current thread
/// until it can be acquired.
///
/// The calling thread will be blocked until there are no more writers which
/// hold the lock. There may be other readers currently inside the lock when
/// this method returns. This method does not provide any guarantees with
/// respect to the ordering of whether contentious readers or writers will
/// acquire the lock first.
///
/// Returns an RAII guard which will release this thread's shared access
/// once it is dropped.
///
/// # Errors
///
/// On Unix this may return an `ErrorKind::Interrupted` if the operation was
/// interrupted by a signal handler.
#[inline]
pub fn read(&self) -> io::Result<RwLockReadGuard<'_, T>> {
let guard = self.lock.read()?;
Ok(RwLockReadGuard::new(guard))
}
/// Attempts to acquire this lock with shared read access.
///
/// If the access could not be granted at this time, then `Err` is returned.
/// Otherwise, an RAII guard is returned which will release the shared access
/// when it is dropped.
///
/// This function does not block.
///
/// This function does not provide any guarantees with respect to the ordering
/// of whether contentious readers or writers will acquire the lock first.
///
/// # Errors
///
/// If the lock is already held and `ErrorKind::WouldBlock` error is returned.
/// On Unix this may return an `ErrorKind::Interrupted` if the operation was
/// interrupted by a signal handler.
#[inline]
pub fn try_read(&self) -> io::Result<RwLockReadGuard<'_, T>> {
let guard = self.lock.try_read()?;
Ok(RwLockReadGuard::new(guard))
}
/// Locks this lock with exclusive write access, blocking the current thread
/// until it can be acquired.
///
/// This function will not return while other writers or other readers
/// currently have access to the lock.
///
/// Returns an RAII guard which will drop the write access of this rwlock
/// when dropped.
///
/// # Errors
///
/// On Unix this may return an `ErrorKind::Interrupted` if the operation was
/// interrupted by a signal handler.
#[inline]
pub fn write(&mut self) -> io::Result<RwLockWriteGuard<'_, T>> {
let guard = self.lock.write()?;
Ok(RwLockWriteGuard::new(guard))
}
/// Attempts to lock this lock with exclusive write access.
///
/// If the lock could not be acquired at this time, then `Err` is returned.
/// Otherwise, an RAII guard is returned which will release the lock when
/// it is dropped.
///
/// # Errors
///
/// If the lock is already held and `ErrorKind::WouldBlock` error is returned.
/// On Unix this may return an `ErrorKind::Interrupted` if the operation was
/// interrupted by a signal handler.
#[inline]
pub fn try_write(&mut self) -> io::Result<RwLockWriteGuard<'_, T>> {
let guard = self.lock.try_write()?;
Ok(RwLockWriteGuard::new(guard))
}
/// Consumes this `RwLock`, returning the underlying data.
#[inline]
pub fn into_inner(self) -> T
where
T: Sized,
{
self.lock.into_inner()
}
}
|
