forked from cloudwego/kitex
/
ring.go
112 lines (99 loc) · 2.53 KB
/
ring.go
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/*
* Copyright 2021 CloudWeGo Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package utils
import (
"errors"
"runtime"
goid "github.com/choleraehyq/pid"
)
// ErrRingFull means the ring is full.
var ErrRingFull = errors.New("ring is full")
// NewRing creates a ringbuffer with fixed size.
func NewRing(size int) *Ring {
if size <= 0 {
panic("new ring with size <=0")
}
r := &Ring{}
// check len(rings):
// 1. len = P/4
// 2. len <= size
numP := runtime.GOMAXPROCS(0)
r.length = (numP + 3) / 4
if r.length > size {
r.length = size
}
// make rings
per := size / r.length
r.rings = make([]*ring, r.length)
for i := 0; i < r.length-1; i++ {
r.rings[i] = newRing(per)
}
r.rings[r.length-1] = newRing(size - per*(r.length-1))
return r
}
// Ring implements a fixed size hash list to manage data
type Ring struct {
length int
rings []*ring
}
// Push appends item to the ring.
func (r *Ring) Push(obj interface{}) error {
if r.length == 1 {
return r.rings[0].Push(obj)
}
idx := goid.GetPid() % r.length
for i := 0; i < r.length; i, idx = i+1, (idx+1)%r.length {
err := r.rings[idx].Push(obj)
if err == nil {
return nil
}
}
return ErrRingFull
}
// Pop returns the last item and removes it from the ring.
func (r *Ring) Pop() interface{} {
if r.length == 1 {
return r.rings[0].Pop()
}
idx := goid.GetPid() % r.length
for i := 0; i < r.length; i, idx = i+1, (idx+1)%r.length {
obj := r.rings[idx].Pop()
if obj != nil {
return obj
}
}
return nil
}
// Dump dumps the data in the ring.
func (r *Ring) Dump() interface{} {
m := &ringDump{}
dumpList := make([]*ringDump, 0, r.length)
idx := goid.GetPid() % r.length
for i := 0; i < r.length; i, idx = i+1, (idx+1)%r.length {
curDump := &ringDump{}
r.rings[idx].Dump(curDump)
dumpList = append(dumpList, curDump)
m.Cap += curDump.Cap
m.Len += curDump.Len
}
m.Array = make([]interface{}, 0, m.Len)
for _, shardData := range dumpList {
for i := 0; i < shardData.Len; i++ {
m.Array = append(m.Array, shardData.Array[i])
}
}
return m
}