Files
engine/common/ring-writer.go
2023-10-17 20:10:48 +08:00

118 lines
2.4 KiB
Go

package common
import (
"sync/atomic"
"m7s.live/engine/v4/util"
)
type emptyLocker struct{}
func (emptyLocker) Lock() {}
func (emptyLocker) Unlock() {}
var EmptyLocker emptyLocker
type RingWriter[T any, F IDataFrame[T]] struct {
*util.Ring[F] `json:"-" yaml:"-"`
ReaderCount atomic.Int32 `json:"-" yaml:"-"`
pool *util.Ring[F]
poolSize int
Size int
LastValue F
constructor func() F
}
func (rb *RingWriter[T, F]) create(n int) (ring *util.Ring[F]) {
ring = util.NewRing[F](n)
for p, i := ring, n; i > 0; p, i = p.Next(), i-1 {
p.Value = rb.constructor()
p.Value.Init()
}
return
}
func (rb *RingWriter[T, F]) Init(n int, constructor func() F) *RingWriter[T, F] {
rb.constructor = constructor
rb.Ring = rb.create(n)
rb.Size = n
rb.LastValue = rb.Value
return rb
}
// func (rb *RingBuffer[T, F]) MoveNext() F {
// rb.LastValue = rb.Value
// rb.Ring = rb.Next()
// return rb.Value
// }
func (rb *RingWriter[T, F]) Glow(size int) (newItem *util.Ring[F]) {
if size < rb.poolSize {
newItem = rb.pool.Unlink(size)
rb.poolSize -= size
} else if size == rb.poolSize {
newItem = rb.pool
rb.poolSize = 0
rb.pool = nil
} else {
newItem = rb.create(size - rb.poolSize).Link(rb.pool)
rb.poolSize = 0
rb.pool = nil
}
rb.Link(newItem)
rb.Size += size
return
}
func (rb *RingWriter[T, F]) Recycle(r *util.Ring[F]) {
rb.poolSize++
r.Value.Init()
r.Value.Reset()
if rb.pool == nil {
rb.pool = r
} else {
rb.pool.Link(r)
}
}
func (rb *RingWriter[T, F]) Reduce(size int) {
r := rb.Unlink(size)
if size > 1 {
for p := r.Next(); p != r; {
next := p.Next() //先保存下一个节点
if p.Value.Discard() == 0 {
rb.Recycle(p.Prev().Unlink(1))
} else {
// fmt.Println("Reduce", p.Value.ReaderCount())
}
p = next
}
}
if r.Value.Discard() == 0 {
rb.Recycle(r)
}
rb.Size -= size
return
}
func (rb *RingWriter[T, F]) Step() (normal bool) {
rb.LastValue.Broadcast() // 防止订阅者还在等待
rb.LastValue = rb.Value
nextSeq := rb.LastValue.GetSequence() + 1
next := rb.Next()
if normal = next.Value.StartWrite(); normal {
next.Value.Reset()
rb.Ring = next
} else {
rb.Reduce(1) //抛弃还有订阅者的节点
rb.Ring = rb.Glow(1) //补充一个新节点
rb.Value.StartWrite()
}
rb.Value.SetSequence(nextSeq)
rb.LastValue.Ready()
return
}
func (rb *RingWriter[T, F]) GetReaderCount() int32 {
return rb.ReaderCount.Load()
}