143 lines
3.2 KiB
Go
143 lines
3.2 KiB
Go
package mutexes
|
|
|
|
import (
|
|
"sync"
|
|
"time"
|
|
)
|
|
|
|
// TimeoutMutex defines a Mutex with timeouts on locks
|
|
type TimeoutMutex interface {
|
|
Mutex
|
|
|
|
// LockFunc is functionally the same as Lock(), but allows setting a custom hook called on timeout
|
|
LockFunc(func()) func()
|
|
}
|
|
|
|
// TimeoutRWMutex defines a RWMutex with timeouts on locks
|
|
type TimeoutRWMutex interface {
|
|
RWMutex
|
|
|
|
// LockFunc is functionally the same as Lock(), but allows setting a custom hook called on timeout
|
|
LockFunc(func()) func()
|
|
|
|
// RLockFunc is functionally the same as RLock(), but allows setting a custom hook called on timeout
|
|
RLockFunc(func()) func()
|
|
}
|
|
|
|
// WithTimeout wraps the supplied Mutex to add a timeout
|
|
func WithTimeout(mu Mutex, d time.Duration) TimeoutMutex {
|
|
return &timeoutMutex{mu: mu, d: d}
|
|
}
|
|
|
|
// WithTimeoutRW wraps the supplied RWMutex to add read/write timeouts
|
|
func WithTimeoutRW(mu RWMutex, rd, wd time.Duration) TimeoutRWMutex {
|
|
return &timeoutRWMutex{mu: mu, rd: rd, wd: wd}
|
|
}
|
|
|
|
// timeoutMutex wraps a Mutex with timeout
|
|
type timeoutMutex struct {
|
|
mu Mutex // mu is the wrapped mutex
|
|
d time.Duration // d is the timeout duration
|
|
}
|
|
|
|
func (mu *timeoutMutex) Lock() func() {
|
|
return mu.LockFunc(func() { panic("lock timed out") })
|
|
}
|
|
|
|
func (mu *timeoutMutex) LockFunc(fn func()) func() {
|
|
return mutexTimeout(mu.d, mu.mu.Lock(), fn)
|
|
}
|
|
|
|
// TimeoutRWMutex wraps a RWMutex with timeouts
|
|
type timeoutRWMutex struct {
|
|
mu RWMutex // mu is the wrapped rwmutex
|
|
rd time.Duration // rd is the rlock timeout duration
|
|
wd time.Duration // wd is the lock timeout duration
|
|
}
|
|
|
|
func (mu *timeoutRWMutex) Lock() func() {
|
|
return mu.LockFunc(func() { panic("lock timed out") })
|
|
}
|
|
|
|
func (mu *timeoutRWMutex) LockFunc(fn func()) func() {
|
|
return mutexTimeout(mu.wd, mu.mu.Lock(), fn)
|
|
}
|
|
|
|
func (mu *timeoutRWMutex) RLock() func() {
|
|
return mu.RLockFunc(func() { panic("rlock timed out") })
|
|
}
|
|
|
|
func (mu *timeoutRWMutex) RLockFunc(fn func()) func() {
|
|
return mutexTimeout(mu.rd, mu.mu.RLock(), fn)
|
|
}
|
|
|
|
// mutexTimeout performs a timed unlock, calling supplied fn if timeout is reached
|
|
func mutexTimeout(d time.Duration, unlock func(), fn func()) func() {
|
|
if d < 1 {
|
|
// No timeout, just unlock
|
|
return unlock
|
|
}
|
|
|
|
// Acquire timer from pool
|
|
t := timerPool.Get().(*timer)
|
|
|
|
// Start the timer
|
|
go t.Start(d, fn)
|
|
|
|
// Return func cancelling timeout,
|
|
// replacing Timeout in pool and
|
|
// finally unlocking mutex
|
|
return func() {
|
|
defer timerPool.Put(t)
|
|
t.Cancel()
|
|
unlock()
|
|
}
|
|
}
|
|
|
|
// timerPool is the global &timer{} pool.
|
|
var timerPool = sync.Pool{
|
|
New: func() interface{} {
|
|
return newtimer()
|
|
},
|
|
}
|
|
|
|
// timer represents a reusable cancellable timer.
|
|
type timer struct {
|
|
t *time.Timer
|
|
c chan struct{}
|
|
}
|
|
|
|
// newtimer returns a new timer instance.
|
|
func newtimer() *timer {
|
|
t := time.NewTimer(time.Minute)
|
|
t.Stop()
|
|
return &timer{t: t, c: make(chan struct{})}
|
|
}
|
|
|
|
// Start will start the timer with duration 'd', performing 'fn' on timeout.
|
|
func (t *timer) Start(d time.Duration, fn func()) {
|
|
t.t.Reset(d)
|
|
select {
|
|
// Timed out
|
|
case <-t.t.C:
|
|
fn()
|
|
|
|
// Cancelled
|
|
case <-t.c:
|
|
}
|
|
}
|
|
|
|
// Cancel will attempt to cancel the running timer.
|
|
func (t *timer) Cancel() {
|
|
select {
|
|
// cancel successful
|
|
case t.c <- struct{}{}:
|
|
if !t.t.Stop() {
|
|
<-t.t.C
|
|
} // stop timer
|
|
|
|
// already stopped
|
|
default:
|
|
}
|
|
}
|