      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

    use cell::UnsafeCell;
    use libc;
    use mem;

    pub struct Mutex { inner: UnsafeCell<libc::pthread_mutex_t> }

    #[inline]
    pub unsafe fn raw(m: &Mutex) -> *mut libc::pthread_mutex_t {
        m.inner.get()
    }

    unsafe impl Send for Mutex {}
    unsafe impl Sync for Mutex {}

    #[allow(dead_code)] // sys isn't exported yet
    impl Mutex {
        pub const fn new() -> Mutex {
            // Might be moved to a different address, so it is better to avoid
            // initialization of potentially opaque OS data before it landed.
            // Be very careful using this newly constructed `Mutex`, reentrant
            // locking is undefined behavior until `init` is called!
            Mutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
        }
        #[inline]
        pub unsafe fn init(&mut self) {
            // Issue #33770
            //
            // A pthread mutex initialized with PTHREAD_MUTEX_INITIALIZER will have
            // a type of PTHREAD_MUTEX_DEFAULT, which has undefined behavior if you
            // try to re-lock it from the same thread when you already hold a lock.
            //
            // In practice, glibc takes advantage of this undefined behavior to
            // implement hardware lock elision, which uses hardware transactional
            // memory to avoid acquiring the lock. While a transaction is in
            // progress, the lock appears to be unlocked. This isn't a problem for
            // other threads since the transactional memory will abort if a conflict
            // is detected, however no abort is generated if re-locking from the
            // same thread.
            //
            // Since locking the same mutex twice will result in two aliasing &mut
            // references, we instead create the mutex with type
            // PTHREAD_MUTEX_NORMAL which is guaranteed to deadlock if we try to
            // re-lock it from the same thread, thus avoiding undefined behavior.
            let mut attr: libc::pthread_mutexattr_t = mem::uninitialized();
            let r = libc::pthread_mutexattr_init(&mut attr);
            debug_assert_eq!(r, 0);
            let r = libc::pthread_mutexattr_settype(&mut attr, libc::PTHREAD_MUTEX_NORMAL);
            debug_assert_eq!(r, 0);
            let r = libc::pthread_mutex_init(self.inner.get(), &attr);
            debug_assert_eq!(r, 0);
            let r = libc::pthread_mutexattr_destroy(&mut attr);
            debug_assert_eq!(r, 0);
        }
        #[inline]
        pub unsafe fn lock(&self) {
            let r = libc::pthread_mutex_lock(self.inner.get());
            debug_assert_eq!(r, 0);
        }
        #[inline]
        pub unsafe fn unlock(&self) {
            let r = libc::pthread_mutex_unlock(self.inner.get());
            debug_assert_eq!(r, 0);
        }
        #[inline]
        pub unsafe fn try_lock(&self) -> bool {
            libc::pthread_mutex_trylock(self.inner.get()) == 0
        }
        #[inline]
        #[cfg(not(target_os = "dragonfly"))]
        pub unsafe fn destroy(&self) {
            let r = libc::pthread_mutex_destroy(self.inner.get());
            debug_assert_eq!(r, 0);
        }
        #[inline]
        #[cfg(target_os = "dragonfly")]
        pub unsafe fn destroy(&self) {
            use libc;
            let r = libc::pthread_mutex_destroy(self.inner.get());
            // On DragonFly pthread_mutex_destroy() returns EINVAL if called on a
            // mutex that was just initialized with libc::PTHREAD_MUTEX_INITIALIZER.
            // Once it is used (locked/unlocked) or pthread_mutex_init() is called,
            // this behaviour no longer occurs.
            debug_assert!(r == 0 || r == libc::EINVAL);
        }
    }

    pub struct ReentrantMutex { inner: UnsafeCell<libc::pthread_mutex_t> }

    unsafe impl Send for ReentrantMutex {}
    unsafe impl Sync for ReentrantMutex {}

    impl ReentrantMutex {
        pub unsafe fn uninitialized() -> ReentrantMutex {
            ReentrantMutex { inner: mem::uninitialized() }
        }

        pub unsafe fn init(&mut self) {
            let mut attr: libc::pthread_mutexattr_t = mem::uninitialized();
            let result = libc::pthread_mutexattr_init(&mut attr as *mut _);
            debug_assert_eq!(result, 0);
            let result = libc::pthread_mutexattr_settype(&mut attr as *mut _,
                                                        libc::PTHREAD_MUTEX_RECURSIVE);
            debug_assert_eq!(result, 0);
            let result = libc::pthread_mutex_init(self.inner.get(), &attr as *const _);
            debug_assert_eq!(result, 0);
            let result = libc::pthread_mutexattr_destroy(&mut attr as *mut _);
            debug_assert_eq!(result, 0);
        }

        pub unsafe fn lock(&self) {
            let result = libc::pthread_mutex_lock(self.inner.get());
            debug_assert_eq!(result, 0);
        }

        #[inline]
        pub unsafe fn try_lock(&self) -> bool {
            libc::pthread_mutex_trylock(self.inner.get()) == 0
        }

        pub unsafe fn unlock(&self) {
            let result = libc::pthread_mutex_unlock(self.inner.get());
            debug_assert_eq!(result, 0);
        }

        pub unsafe fn destroy(&self) {
            let result = libc::pthread_mutex_destroy(self.inner.get());
            debug_assert_eq!(result, 0);
        }
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)