143 lines
2.2 KiB
Go
143 lines
2.2 KiB
Go
// Package memory provides a sync.Mutex implementation of the lock for local use
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package memory
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import (
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"sync"
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"time"
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lock "github.com/micro/go-micro/sync/lock"
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)
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type memoryLock struct {
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sync.RWMutex
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locks map[string]*mlock
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}
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type mlock struct {
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id string
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time time.Time
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ttl time.Duration
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release chan bool
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}
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func (m *memoryLock) Acquire(id string, opts ...lock.AcquireOption) error {
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// lock our access
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m.Lock()
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var options lock.AcquireOptions
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for _, o := range opts {
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o(&options)
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}
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lk, ok := m.locks[id]
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if !ok {
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m.locks[id] = &mlock{
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id: id,
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time: time.Now(),
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ttl: options.TTL,
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release: make(chan bool),
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}
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// unlock
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m.Unlock()
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return nil
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}
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m.Unlock()
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// set wait time
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var wait <-chan time.Time
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var ttl <-chan time.Time
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// decide if we should wait
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if options.Wait > time.Duration(0) {
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wait = time.After(options.Wait)
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}
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// check the ttl of the lock
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if lk.ttl > time.Duration(0) {
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// time lived for the lock
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live := time.Since(lk.time)
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// set a timer for the leftover ttl
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if live > lk.ttl {
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// release the lock if it expired
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m.Release(id)
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} else {
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ttl = time.After(live)
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}
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}
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lockLoop:
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for {
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// wait for the lock to be released
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select {
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case <-lk.release:
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m.Lock()
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// someone locked before us
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lk, ok = m.locks[id]
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if ok {
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m.Unlock()
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continue
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}
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// got chance to lock
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m.locks[id] = &mlock{
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id: id,
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time: time.Now(),
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ttl: options.TTL,
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release: make(chan bool),
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}
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m.Unlock()
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break lockLoop
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case <-ttl:
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// ttl exceeded
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m.Release(id)
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// TODO: check the ttl again above
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ttl = nil
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// try acquire
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continue
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case <-wait:
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return lock.ErrLockTimeout
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}
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}
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return nil
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}
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func (m *memoryLock) Release(id string) error {
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m.Lock()
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defer m.Unlock()
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lk, ok := m.locks[id]
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// no lock exists
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if !ok {
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return nil
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}
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// delete the lock
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delete(m.locks, id)
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select {
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case <-lk.release:
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return nil
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default:
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close(lk.release)
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}
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return nil
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}
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func NewLock(opts ...lock.Option) lock.Lock {
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var options lock.Options
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for _, o := range opts {
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o(&options)
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}
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return &memoryLock{
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locks: make(map[string]*mlock),
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}
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}
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