Golang atomic.StorePointer函數代碼示例

// Set background error.
func (d *DB) seterr(err error) {
	if err == nil {
		atomic.StorePointer(&d.err, nil)
	} else {
		atomic.StorePointer(&d.err, unsafe.Pointer(&errWrap{err}))
	}
}

func (b *Bucket) Refresh() error {
	pool := b.pool
	tmpb := &Bucket{}
	err := pool.client.parseURLResponse(b.URI, tmpb)
	if err != nil {
		return err
	}
	newcps := make([]*connectionPool, len(tmpb.VBSMJson.ServerList))
	for i := range newcps {
		if b.ah != nil {
			newcps[i] = newConnectionPool(
				tmpb.VBSMJson.ServerList[i],
				b.ah, PoolSize, PoolOverflow)

		} else {
			newcps[i] = newConnectionPool(
				tmpb.VBSMJson.ServerList[i],
				b.authHandler(), PoolSize, PoolOverflow)
		}
	}
	b.replaceConnPools(newcps)
	tmpb.ah = b.ah
	atomic.StorePointer(&b.vBucketServerMap, unsafe.Pointer(&tmpb.VBSMJson))
	atomic.StorePointer(&b.nodeList, unsafe.Pointer(&tmpb.NodesJSON))
	return nil
}

func (p *partitionstore) visitItems(start []byte, withValue bool,
	visitor func(*item) bool) (err error) {
	keys, changes := p.colls()
	var vErr error
	v := func(kItem *gkvlite.Item) bool {
		i := (*item)(atomic.LoadPointer(&kItem.Transient))
		if i != nil {
			return visitor(i)
		}
		var cItem *gkvlite.Item
		cItem, vErr = changes.GetItem(kItem.Val, true)
		if vErr != nil {
			return false
		}
		if cItem == nil {
			return true // TODO: track this case; might have been compacted away.
		}
		i = (*item)(atomic.LoadPointer(&cItem.Transient))
		if i != nil {
			atomic.StorePointer(&kItem.Transient, unsafe.Pointer(i))
			return visitor(i)
		}
		i = &item{key: kItem.Key}
		if vErr = i.fromValueBytes(cItem.Val); vErr != nil {
			return false
		}
		atomic.StorePointer(&cItem.Transient, unsafe.Pointer(i))
		atomic.StorePointer(&kItem.Transient, unsafe.Pointer(i))
		return visitor(i)
	}
	if err := p.visit(keys, start, true, v); err != nil {
		return err
	}
	return vErr
}

func (nloc *nodeLoc) Copy(src *nodeLoc) *nodeLoc {
	if src == nil {
		return nloc.Copy(empty_nodeLoc)
	}
	atomic.StorePointer(&nloc.loc, unsafe.Pointer(src.Loc()))
	atomic.StorePointer(&nloc.node, unsafe.Pointer(src.Node()))
	return nloc
}

func (i *itemLoc) Copy(src *itemLoc) {
	if src == nil {
		i.Copy(empty_itemLoc)
		return
	}
	atomic.StorePointer(&i.loc, unsafe.Pointer(src.Loc()))
	atomic.StorePointer(&i.item, unsafe.Pointer(src.Item()))
}

func (p *partitionstore) collsPauseSwap(cb func() (keys, changes *gkvlite.Collection)) {
	p.lock.Lock()
	defer p.lock.Unlock()

	k, c := cb()

	// Update the changes first, so that readers see a key index that's older.
	atomic.StorePointer(&p.changes, unsafe.Pointer(c))
	atomic.StorePointer(&p.keys, unsafe.Pointer(k))
}

// RLock readlock resurs from thread
// uses double check
func (t *TControl) RLock(threadId uint16, resursId string) {
	var wlock *string
	for {
		wlock = (*string)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&t.writer))))
		if wlock == nil || *wlock != resursId {
			atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&t.readers[threadId])), unsafe.Pointer(&resursId))
			wlock = (*string)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&t.writer))))
			if wlock == nil || *wlock != resursId {
				return
			}
			atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&t.readers[threadId])), nil)
		}
		t.sleep()
	}
}

func TestAtomicPointer() {
	b1 := &B{
		B1: 3,
		B2: "33",
	}
	atomic.StorePointer(&bp, unsafe.Pointer(b1))
	fmt.Println(*((*B)(bp))) // {3 33}

	//	atomic.StorePointer(&unsafe.Pointer(b), unsafe.Pointer(b1)) // yonka_test\test_json.go:1472: cannot take the address of unsafe.Pointer(b)
	b := &B{1, "11"}
	p := unsafe.Pointer(b)
	atomic.StorePointer(&p, unsafe.Pointer(b1))
	fmt.Println(*((*B)(p))) // {3 33}
	fmt.Println(*b)         // {1 11}
}

func ParseConfig(cfg string) {
	if cfg == "" {
		log.Fatalln("config file not specified: use -c $filename")
	}

	if !file.IsExist(cfg) {
		log.Fatalln("config file specified not found:", cfg)
	}

	ConfigFile = cfg

	configContent, err := file.ToTrimString(cfg)
	if err != nil {
		log.Fatalln("read config file", cfg, "error:", err.Error())
	}

	var c GlobalConfig
	err = json.Unmarshal([]byte(configContent), &c)
	if err != nil {
		log.Fatalln("parse config file", cfg, "error:", err.Error())
	}

	if c.Migrate.Enabled && len(c.Migrate.Cluster) == 0 {
		c.Migrate.Enabled = false
	}

	// set config
	atomic.StorePointer(&ptr, unsafe.Pointer(&c))

	log.Println("g.ParseConfig ok, file", cfg)
}

func ReadFirst(b []byte, v interface{}) (read bool, total int, err error) {
	var t unsafe.Pointer
	var r *[2]marshal.Reader
	if t = readerCache; t != nil {
		if atomic.CompareAndSwapPointer(&readerCache, t, nil) {
			r = (*[2]marshal.Reader)(t)
			*r = [2]marshal.Reader{{Body: b}, {}}
			goto Got
		}
	}
	r = &[2]marshal.Reader{{Body: b}, {}}
Got:
	total = r[0].IntUint32()
	if total > 0 {
		sz := r[0].IntUint32()
		if r[0].Err == nil {
			r[1].Body = r[0].Slice(sz + 4)
			err = ReadRawTuple(&r[1], v)
			read = true
		} else {
			err = r[0].Err
		}
	}
	atomic.StorePointer(&readerCache, unsafe.Pointer(r))
	return
}

func (m *SharedMap) SetValue(key KeyType, value ValType) {
	m.writeLock.Lock()
	defer m.writeLock.Unlock()
	newCurrent := m.Copy()
	(*newCurrent)[key] = value
	atomic.StorePointer(&m.current, unsafe.Pointer(newCurrent))
}

func (nloc *nodeLoc) write(o *Store) error {
	if nloc != nil && nloc.Loc().isEmpty() {
		node := nloc.Node()
		if node == nil {
			return nil
		}
		offset := atomic.LoadInt64(&o.size)
		length := ploc_length + ploc_length + ploc_length + 8 + 8
		b := make([]byte, length)
		pos := 0
		pos = node.item.Loc().write(b, pos)
		pos = node.left.Loc().write(b, pos)
		pos = node.right.Loc().write(b, pos)
		binary.BigEndian.PutUint64(b[pos:pos+8], node.numNodes)
		pos += 8
		binary.BigEndian.PutUint64(b[pos:pos+8], node.numBytes)
		pos += 8
		if pos != length {
			return fmt.Errorf("nodeLoc.write() pos: %v didn't match length: %v",
				pos, length)
		}
		if _, err := o.file.WriteAt(b, offset); err != nil {
			return err
		}
		atomic.StoreInt64(&o.size, offset+int64(length))
		atomic.StorePointer(&nloc.loc,
			unsafe.Pointer(&ploc{Offset: offset, Length: uint32(length)}))
	}
	return nil
}

func (s *bucketstore) compactSwapFile(bsf *bucketstorefile, compactPath string) error {
	idx, ver, err := parseStoreFileName(filepath.Base(bsf.path), STORE_FILE_SUFFIX)
	if err != nil {
		return err
	}

	nextName := makeStoreFileName(idx, ver+1, STORE_FILE_SUFFIX)
	nextPath := path.Join(filepath.Dir(bsf.path), nextName)

	if err = os.Rename(compactPath, nextPath); err != nil {
		return err
	}

	nextFile, err := fileService.OpenFile(nextPath, os.O_RDWR|os.O_CREATE)
	if err != nil {
		return err
	}

	nextBSF := NewBucketStoreFile(nextPath, nextFile, bsf.stats)
	nextStore, err := gkvlite.NewStore(nextBSF)
	if err != nil {
		// TODO: Rollback the previous *.orig rename.
		return err
	}
	nextBSF.store = nextStore

	atomic.StorePointer(&s.bsf, unsafe.Pointer(nextBSF))

	bsf.apply(func() {
		bsf.purge = true // Mark the old file as purgable.
	})

	return nil
}

// Create new memdb and froze the old one; need external synchronization.
func (d *DB) newMem() (m *memdb.DB, err error) {
	s := d.s

	num := s.allocFileNum()
	w, err := newJournalWriter(s.getJournalFile(num))
	if err != nil {
		s.reuseFileNum(num)
		return
	}

	old := d.journal
	d.journal = w
	if old != nil {
		old.close()
		d.fjournal = old
	}

	d.fseq = d.seq

	m = memdb.New(s.cmp)
	mem := &memSet{cur: m}
	if old := d.getMem_NB(); old != nil {
		mem.froze = old.cur
	}
	atomic.StorePointer(&d.mem, unsafe.Pointer(mem))

	return
}

// NewRange initializes the range using the given metadata.
func NewRange(desc *proto.RangeDescriptor, rm rangeManager) (*Range, error) {
	r := &Range{
		rm:          rm,
		cmdQ:        NewCommandQueue(),
		tsCache:     NewTimestampCache(rm.Clock()),
		respCache:   NewResponseCache(desc.RaftID, rm.Engine()),
		pendingCmds: map[cmdIDKey]*pendingCmd{},
	}
	r.setDescWithoutProcessUpdate(desc)

	lastIndex, err := r.loadLastIndex()
	if err != nil {
		return nil, err
	}
	atomic.StoreUint64(&r.lastIndex, lastIndex)

	appliedIndex, err := r.loadAppliedIndex(r.rm.Engine())
	if err != nil {
		return nil, err
	}
	atomic.StoreUint64(&r.appliedIndex, appliedIndex)

	lease, err := loadLeaderLease(r.rm.Engine(), desc.RaftID)
	if err != nil {
		return nil, err
	}
	atomic.StorePointer(&r.lease, unsafe.Pointer(lease))

	if r.stats, err = newRangeStats(desc.RaftID, rm.Engine()); err != nil {
		return nil, err
	}

	return r, nil
}