gotosocial/vendor/codeberg.org/gruf/go-mutexes/mutex_timeout.go
2021-11-13 12:29:08 +01:00

106 lines
2.6 KiB
Go

package mutexes
import (
"sync"
"time"
"codeberg.org/gruf/go-nowish"
)
// 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)
}
// timeoutPool provides nowish.Timeout objects for timeout mutexes
var timeoutPool = sync.Pool{
New: func() interface{} {
t := nowish.NewTimeout()
return &t
},
}
// 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 timeout obj
t := timeoutPool.Get().(*nowish.Timeout)
// Start the timeout with hook
t.Start(d, fn)
// Return func cancelling timeout,
// replacing Timeout in pool and
// finally unlocking mutex
return func() {
t.Cancel()
timeoutPool.Put(t)
unlock()
}
}