421 lines
14 KiB
Rust
421 lines
14 KiB
Rust
// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! A native mutex and condition variable type
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//!
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//! This module contains bindings to the platform's native mutex/condition
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//! variable primitives. It provides a single type, `Mutex`, which can be
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//! statically initialized via the `MUTEX_INIT` value. This object serves as both a
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//! mutex and a condition variable simultaneously.
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//!
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//! The lock is lazily initialized, but it can only be unsafely destroyed. A
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//! statically initialized lock doesn't necessarily have a time at which it can
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//! get deallocated. For this reason, there is no `Drop` implementation of the
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//! mutex, but rather the `destroy()` method must be invoked manually if
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//! destruction of the mutex is desired.
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//!
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//! It is not recommended to use this type for idiomatic rust use. This type is
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//! appropriate where no other options are available, but other rust concurrency
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//! primitives should be used before this type.
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//!
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//! # Example
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//!
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//! use std::unstable::mutex::{Mutex, MUTEX_INIT};
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//!
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//! // Use a statically initialized mutex
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//! static mut lock: Mutex = MUTEX_INIT;
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//!
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//! unsafe {
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//! lock.lock();
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//! lock.unlock();
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//! }
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//!
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//! // Use a normally initialized mutex
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//! let mut lock = Mutex::new();
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//! unsafe {
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//! lock.lock();
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//! lock.unlock();
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//! lock.destroy();
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//! }
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#[allow(non_camel_case_types)];
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pub struct Mutex {
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priv inner: imp::Mutex,
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}
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pub static MUTEX_INIT: Mutex = Mutex {
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inner: imp::MUTEX_INIT,
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};
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impl Mutex {
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/// Creates a new mutex
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pub unsafe fn new() -> Mutex {
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Mutex { inner: imp::Mutex::new() }
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}
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/// Acquires this lock. This assumes that the current thread does not
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/// already hold the lock.
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pub unsafe fn lock(&mut self) { self.inner.lock() }
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/// Attempts to acquire the lock. The value returned is whether the lock was
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/// acquired or not
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pub unsafe fn trylock(&mut self) -> bool { self.inner.trylock() }
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/// Unlocks the lock. This assumes that the current thread already holds the
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/// lock.
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pub unsafe fn unlock(&mut self) { self.inner.unlock() }
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/// Block on the internal condition variable.
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///
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/// This function assumes that the lock is already held
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pub unsafe fn wait(&mut self) { self.inner.wait() }
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/// Signals a thread in `wait` to wake up
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pub unsafe fn signal(&mut self) { self.inner.signal() }
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/// This function is especially unsafe because there are no guarantees made
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/// that no other thread is currently holding the lock or waiting on the
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/// condition variable contained inside.
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pub unsafe fn destroy(&mut self) { self.inner.destroy() }
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}
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#[cfg(unix)]
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mod imp {
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use libc;
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use self::os::{PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER,
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pthread_mutex_t, pthread_cond_t};
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use unstable::intrinsics;
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type pthread_mutexattr_t = libc::c_void;
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type pthread_condattr_t = libc::c_void;
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#[cfg(target_os = "freebsd")]
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mod os {
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use libc;
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pub type pthread_mutex_t = *libc::c_void;
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pub type pthread_cond_t = *libc::c_void;
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pub static PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t =
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0 as pthread_mutex_t;
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pub static PTHREAD_COND_INITIALIZER: pthread_cond_t =
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0 as pthread_cond_t;
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}
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#[cfg(target_os = "macos")]
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mod os {
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use libc;
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#[cfg(target_arch = "x86_64")]
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static __PTHREAD_MUTEX_SIZE__: uint = 56;
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#[cfg(target_arch = "x86_64")]
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static __PTHREAD_COND_SIZE__: uint = 40;
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#[cfg(target_arch = "x86")]
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static __PTHREAD_MUTEX_SIZE__: uint = 40;
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#[cfg(target_arch = "x86")]
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static __PTHREAD_COND_SIZE__: uint = 24;
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static _PTHREAD_MUTEX_SIG_init: libc::c_long = 0x32AAABA7;
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static _PTHREAD_COND_SIG_init: libc::c_long = 0x3CB0B1BB;
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pub struct pthread_mutex_t {
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__sig: libc::c_long,
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__opaque: [u8, ..__PTHREAD_MUTEX_SIZE__],
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}
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pub struct pthread_cond_t {
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__sig: libc::c_long,
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__opaque: [u8, ..__PTHREAD_COND_SIZE__],
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}
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pub static PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
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__sig: _PTHREAD_MUTEX_SIG_init,
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__opaque: [0, ..__PTHREAD_MUTEX_SIZE__],
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};
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pub static PTHREAD_COND_INITIALIZER: pthread_cond_t = pthread_cond_t {
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__sig: _PTHREAD_COND_SIG_init,
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__opaque: [0, ..__PTHREAD_COND_SIZE__],
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};
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}
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#[cfg(target_os = "linux")]
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mod os {
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use libc;
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// minus 8 because we have an 'align' field
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#[cfg(target_arch = "x86_64")]
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static __SIZEOF_PTHREAD_MUTEX_T: uint = 40 - 8;
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#[cfg(target_arch = "x86")]
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static __SIZEOF_PTHREAD_MUTEX_T: uint = 24 - 8;
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#[cfg(target_arch = "arm")]
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static __SIZEOF_PTHREAD_MUTEX_T: uint = 24 - 8;
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#[cfg(target_arch = "x86_64")]
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static __SIZEOF_PTHREAD_COND_T: uint = 48 - 8;
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#[cfg(target_arch = "x86")]
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static __SIZEOF_PTHREAD_COND_T: uint = 48 - 8;
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#[cfg(target_arch = "arm")]
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static __SIZEOF_PTHREAD_COND_T: uint = 48 - 8;
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pub struct pthread_mutex_t {
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__align: libc::c_longlong,
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size: [u8, ..__SIZEOF_PTHREAD_MUTEX_T],
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}
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pub struct pthread_cond_t {
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__align: libc::c_longlong,
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size: [u8, ..__SIZEOF_PTHREAD_COND_T],
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}
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pub static PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
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__align: 0,
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size: [0, ..__SIZEOF_PTHREAD_MUTEX_T],
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};
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pub static PTHREAD_COND_INITIALIZER: pthread_cond_t = pthread_cond_t {
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__align: 0,
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size: [0, ..__SIZEOF_PTHREAD_COND_T],
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};
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}
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#[cfg(target_os = "android")]
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mod os {
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use libc;
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pub struct pthread_mutex_t { value: libc::c_int }
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pub struct pthread_cond_t { value: libc::c_int }
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pub static PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
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value: 0,
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};
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pub static PTHREAD_COND_INITIALIZER: pthread_cond_t = pthread_cond_t {
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value: 0,
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};
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}
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pub struct Mutex {
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priv lock: pthread_mutex_t,
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priv cond: pthread_cond_t,
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}
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pub static MUTEX_INIT: Mutex = Mutex {
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lock: PTHREAD_MUTEX_INITIALIZER,
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cond: PTHREAD_COND_INITIALIZER,
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};
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impl Mutex {
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pub unsafe fn new() -> Mutex {
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let mut m = Mutex {
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lock: intrinsics::init(),
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cond: intrinsics::init(),
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};
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pthread_mutex_init(&mut m.lock, 0 as *libc::c_void);
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pthread_cond_init(&mut m.cond, 0 as *libc::c_void);
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return m;
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}
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pub unsafe fn lock(&mut self) { pthread_mutex_lock(&mut self.lock); }
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pub unsafe fn unlock(&mut self) { pthread_mutex_unlock(&mut self.lock); }
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pub unsafe fn signal(&mut self) { pthread_cond_signal(&mut self.cond); }
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pub unsafe fn wait(&mut self) {
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pthread_cond_wait(&mut self.cond, &mut self.lock);
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}
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pub unsafe fn trylock(&mut self) -> bool {
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pthread_mutex_trylock(&mut self.lock) == 0
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}
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pub unsafe fn destroy(&mut self) {
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pthread_mutex_destroy(&mut self.lock);
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pthread_cond_destroy(&mut self.cond);
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}
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}
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extern {
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fn pthread_mutex_init(lock: *mut pthread_mutex_t,
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attr: *pthread_mutexattr_t) -> libc::c_int;
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fn pthread_mutex_destroy(lock: *mut pthread_mutex_t) -> libc::c_int;
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fn pthread_cond_init(cond: *mut pthread_cond_t,
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attr: *pthread_condattr_t) -> libc::c_int;
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fn pthread_cond_destroy(cond: *mut pthread_cond_t) -> libc::c_int;
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fn pthread_mutex_lock(lock: *mut pthread_mutex_t) -> libc::c_int;
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fn pthread_mutex_trylock(lock: *mut pthread_mutex_t) -> libc::c_int;
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fn pthread_mutex_unlock(lock: *mut pthread_mutex_t) -> libc::c_int;
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fn pthread_cond_wait(cond: *mut pthread_cond_t,
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lock: *mut pthread_mutex_t) -> libc::c_int;
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fn pthread_cond_signal(cond: *mut pthread_cond_t) -> libc::c_int;
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}
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}
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#[cfg(windows)]
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mod imp {
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use rt::global_heap::malloc_raw;
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use libc::{HANDLE, BOOL, LPSECURITY_ATTRIBUTES, c_void, DWORD, LPCSTR};
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use libc;
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use ptr;
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use sync::atomics;
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type LPCRITICAL_SECTION = *mut c_void;
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static SPIN_COUNT: DWORD = 4000;
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#[cfg(target_arch = "x86")]
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static CRIT_SECTION_SIZE: uint = 24;
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pub struct Mutex {
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// pointers for the lock/cond handles, atomically updated
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priv lock: atomics::AtomicUint,
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priv cond: atomics::AtomicUint,
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}
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pub static MUTEX_INIT: Mutex = Mutex {
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lock: atomics::INIT_ATOMIC_UINT,
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cond: atomics::INIT_ATOMIC_UINT,
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};
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impl Mutex {
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pub unsafe fn new() -> Mutex {
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Mutex {
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lock: atomics::AtomicUint::new(init_lock()),
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cond: atomics::AtomicUint::new(init_cond()),
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}
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}
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pub unsafe fn lock(&mut self) {
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EnterCriticalSection(self.getlock() as LPCRITICAL_SECTION)
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}
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pub unsafe fn trylock(&mut self) -> bool {
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TryEnterCriticalSection(self.getlock() as LPCRITICAL_SECTION) != 0
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}
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pub unsafe fn unlock(&mut self) {
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LeaveCriticalSection(self.getlock() as LPCRITICAL_SECTION)
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}
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pub unsafe fn wait(&mut self) {
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self.unlock();
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WaitForSingleObject(self.getcond() as HANDLE, libc::INFINITE);
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self.lock();
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}
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pub unsafe fn signal(&mut self) {
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assert!(SetEvent(self.getcond() as HANDLE) != 0);
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}
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/// This function is especially unsafe because there are no guarantees made
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/// that no other thread is currently holding the lock or waiting on the
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/// condition variable contained inside.
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pub unsafe fn destroy(&mut self) {
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let lock = self.lock.swap(0, atomics::SeqCst);
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let cond = self.cond.swap(0, atomics::SeqCst);
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if lock != 0 { free_lock(lock) }
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if cond != 0 { free_cond(cond) }
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}
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unsafe fn getlock(&mut self) -> *mut c_void {
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match self.lock.load(atomics::SeqCst) {
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0 => {}
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n => return n as *mut c_void
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}
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let lock = init_lock();
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match self.lock.compare_and_swap(0, lock, atomics::SeqCst) {
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0 => return lock as *mut c_void,
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_ => {}
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}
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free_lock(lock);
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return self.lock.load(atomics::SeqCst) as *mut c_void;
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}
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unsafe fn getcond(&mut self) -> *mut c_void {
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match self.cond.load(atomics::SeqCst) {
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0 => {}
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n => return n as *mut c_void
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}
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let cond = init_cond();
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match self.cond.compare_and_swap(0, cond, atomics::SeqCst) {
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0 => return cond as *mut c_void,
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_ => {}
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}
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free_cond(cond);
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return self.cond.load(atomics::SeqCst) as *mut c_void;
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}
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}
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pub unsafe fn init_lock() -> uint {
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let block = malloc_raw(CRIT_SECTION_SIZE as uint) as *mut c_void;
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InitializeCriticalSectionAndSpinCount(block, SPIN_COUNT);
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return block as uint;
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}
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pub unsafe fn init_cond() -> uint {
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return CreateEventA(ptr::mut_null(), libc::FALSE, libc::FALSE,
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ptr::null()) as uint;
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}
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pub unsafe fn free_lock(h: uint) {
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DeleteCriticalSection(h as LPCRITICAL_SECTION);
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libc::free(h as *mut c_void);
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}
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pub unsafe fn free_cond(h: uint) {
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let block = h as HANDLE;
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libc::CloseHandle(block);
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}
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extern "system" {
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fn CreateEventA(lpSecurityAttributes: LPSECURITY_ATTRIBUTES,
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bManualReset: BOOL,
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bInitialState: BOOL,
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lpName: LPCSTR) -> HANDLE;
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fn InitializeCriticalSectionAndSpinCount(
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lpCriticalSection: LPCRITICAL_SECTION,
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dwSpinCount: DWORD) -> BOOL;
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fn DeleteCriticalSection(lpCriticalSection: LPCRITICAL_SECTION);
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fn EnterCriticalSection(lpCriticalSection: LPCRITICAL_SECTION);
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fn LeaveCriticalSection(lpCriticalSection: LPCRITICAL_SECTION);
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fn TryEnterCriticalSection(lpCriticalSection: LPCRITICAL_SECTION) -> BOOL;
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fn SetEvent(hEvent: HANDLE) -> BOOL;
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fn WaitForSingleObject(hHandle: HANDLE, dwMilliseconds: DWORD) -> DWORD;
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}
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}
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#[cfg(test)]
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mod test {
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use prelude::*;
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use super::{Mutex, MUTEX_INIT};
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use rt::thread::Thread;
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#[test]
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fn somke_lock() {
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static mut lock: Mutex = MUTEX_INIT;
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unsafe {
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lock.lock();
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lock.unlock();
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}
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}
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#[test]
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fn somke_cond() {
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static mut lock: Mutex = MUTEX_INIT;
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unsafe {
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lock.lock();
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let t = Thread::start(proc() {
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lock.lock();
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lock.signal();
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lock.unlock();
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});
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lock.wait();
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lock.unlock();
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t.join();
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}
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}
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#[test]
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fn destroy_immediately() {
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unsafe {
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let mut m = Mutex::new();
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m.destroy();
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}
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}
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}
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