100 lines
1.9 KiB
Go
100 lines
1.9 KiB
Go
package cache
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import (
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"context"
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"errors"
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"fmt"
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"github.com/fthvgb1/wp-go/safety"
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"sync"
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"time"
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)
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type VarCache[T any] struct {
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v safety.Var[vars[T]]
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}
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type vars[T any] struct {
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data T
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mutex *sync.Mutex
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setCacheFunc func(...any) (T, error)
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expireTime time.Duration
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setTime time.Time
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incr int
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}
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func (c *VarCache[T]) GetLastSetTime() time.Time {
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return c.v.Load().setTime
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}
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func NewVarCache[T any](fun func(...any) (T, error), duration time.Duration) *VarCache[T] {
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return &VarCache[T]{
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v: safety.NewVar(vars[T]{
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mutex: &sync.Mutex{},
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setCacheFunc: fun,
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expireTime: duration,
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}),
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}
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}
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func (c *VarCache[T]) IsExpired() bool {
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v := c.v.Load()
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return time.Duration(v.setTime.UnixNano())+v.expireTime < time.Duration(time.Now().UnixNano())
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}
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func (c *VarCache[T]) Flush() {
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v := c.v.Load()
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mu := v.mutex
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mu.Lock()
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defer mu.Unlock()
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var vv T
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v.data = vv
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c.v.Store(v)
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}
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func (c *VarCache[T]) GetCache(ctx context.Context, timeout time.Duration, params ...any) (T, error) {
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v := c.v.Load()
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data := v.data
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var err error
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if v.expireTime <= 0 || ((time.Duration(v.setTime.UnixNano()) + v.expireTime) < time.Duration(time.Now().UnixNano())) {
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t := v.incr
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call := func() {
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v.mutex.Lock()
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defer v.mutex.Unlock()
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vv := c.v.Load()
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if vv.incr > t {
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return
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}
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r, er := vv.setCacheFunc(params...)
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if err != nil {
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err = er
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return
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}
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vv.setTime = time.Now()
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vv.data = r
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data = r
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vv.incr++
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c.v.Store(vv)
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}
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if timeout > 0 {
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ctx, cancel := context.WithTimeout(ctx, timeout)
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defer cancel()
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done := make(chan struct{}, 1)
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go func() {
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call()
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done <- struct{}{}
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close(done)
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}()
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select {
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case <-ctx.Done():
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err = errors.New(fmt.Sprintf("get cache %s", ctx.Err().Error()))
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case <-done:
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}
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} else {
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call()
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}
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}
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return data, err
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}
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