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region.go
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/
region.go
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package util
import (
"encoding/json"
"sync"
"github.com/biogo/store/llrb"
"github.com/juju/errors"
"github.com/dearcode/candy/meta"
"github.com/dearcode/candy/util/log"
)
var (
//ErrRegionNotFound region not exist.
ErrRegionNotFound = errors.New("region not found")
)
//Regions 保存region的路由信息.
type Regions struct {
mu sync.RWMutex
tree *llrb.Tree
hosts map[string]*meta.Region
}
//NewRegions 初始化llrb,map.
func NewRegions(ops ...RegionsOption) (*Regions, error) {
r := &Regions{tree: &llrb.Tree{}, hosts: make(map[string]*meta.Region)}
for _, op := range ops {
if err := op(r); err != nil {
return nil, err
}
}
return r, nil
}
// RegionsOption Regions option.
type RegionsOption func(*Regions) error
//RegionsWithHosts 初始化hosts
func RegionsWithHosts(hosts string) RegionsOption {
return func(r *Regions) error {
if err := json.Unmarshal([]byte(hosts), &r.hosts); err != nil {
return err
}
for _, v := range r.hosts {
r.tree.Insert(v)
}
return nil
}
}
//Max 当前跨度最大的节点
func (r *Regions) Max() (meta.Region, error) {
r.mu.RLock()
defer r.mu.RUnlock()
if r.tree.Len() == 0 {
return meta.Region{}, ErrRegionNotFound
}
var o *meta.Region
r.tree.Do(func(c llrb.Comparable) (done bool) {
n := c.(*meta.Region)
if o == nil || n.Span()-o.Span() >= o.Span()/2 {
o = n
}
return
})
return *o, nil
}
//Split 添加一个节点并分割相对大的节点.
func (r *Regions) Split(from, to string) (meta.Region, error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.tree.Len() == 0 {
n := meta.NewRegion(to, 0, meta.MaxRegionEnd)
r.tree.Insert(n)
r.hosts[to] = n
return *n, nil
}
f, ok := r.hosts[from]
if !ok {
log.Infof("from %s not found", from)
return meta.Region{}, ErrRegionNotFound
}
t, ok := r.hosts[to]
if ok {
log.Infof("new region %s exist", to)
return *t, nil
}
delta := (f.End - f.Begin) / 2
t = meta.NewRegion(to, f.End-delta, f.End)
r.tree.Delete(f)
f.End -= delta
r.tree.Insert(f)
r.tree.Insert(t)
r.hosts[to] = t
return *t, nil
}
//Get 根据ID获取对应的region信息
func (r *Regions) Get(id int64) (meta.Region, bool) {
b := int32(id % meta.MaxRegionEnd)
r.mu.RLock()
c := r.tree.Get(&meta.Region{Begin: b})
if c == nil {
return meta.Region{}, false
}
src := c.(*meta.Region)
r.mu.RUnlock()
return *src, true
}
//GetByHost 根据host获取对应的region信息.
func (r *Regions) GetByHost(host string) (meta.Region, error) {
r.mu.RLock()
if src, ok := r.hosts[host]; ok {
r.mu.RUnlock()
return *src, nil
}
r.mu.RUnlock()
return meta.Region{}, ErrRegionNotFound
}
// Next 返回当前节点的下一个节点
func (r *Regions) Next(host string) (self meta.Region, next meta.Region, err error) {
r.mu.Lock()
defer r.mu.Unlock()
f, ok := r.hosts[host]
if !ok {
log.Infof("host:%s not found", host)
err = ErrRegionNotFound
return
}
if r.tree.Len() == 1 {
log.Infof("only one region")
err = ErrRegionNotFound
return
}
begin := f.End
if begin == meta.MaxRegionEnd {
begin = f.Begin - 1
}
c := r.tree.Get(&meta.Region{Begin: begin})
if c == nil {
log.Infof("region begin:%d not found", begin)
err = ErrRegionNotFound
return
}
self = *f
next = *c.(*meta.Region)
return
}
// Merge 合并节点,合并当前删除的节点到前一个节点
func (r *Regions) Merge(from, to string) error {
r.mu.Lock()
defer r.mu.Unlock()
f, ok := r.hosts[from]
if !ok {
log.Infof("from %s not found", from)
return ErrRegionNotFound
}
t, ok := r.hosts[to]
if !ok {
log.Infof("to %s not found", to)
return ErrRegionNotFound
}
r.tree.Delete(f)
r.tree.Delete(t)
delete(r.hosts, from)
t.Begin, t.End = f.Max(*t)
r.tree.Insert(t)
return nil
}
//Marshal 导出json格式数据
func (r *Regions) Marshal() (b []byte, e error) {
r.mu.RLock()
b, e = json.Marshal(r.hosts)
r.mu.RUnlock()
return
}
//Dump 导出region
func (r *Regions) Dump() []meta.Region {
var l []meta.Region
r.mu.RLock()
for _, v := range r.hosts {
l = append(l, *v)
}
r.mu.RUnlock()
return l
}