Golang Transactor.Transact方法代码示例

func setOne(t fdb.Transactor, key []byte, value []byte) {
	fmt.Printf("setOne got:  %T\n", t)
	t.Transact(func(tr fdb.Transaction) (interface{}, error) {
		// We don't actually call tr.Set here to avoid mutating a real database.
		// tr.Set(key, value)
		return nil, nil
	})
}

func setMany(t fdb.Transactor, value []byte, keys ...[]byte) {
	fmt.Printf("setMany got: %T\n", t)
	t.Transact(func(tr fdb.Transaction) (interface{}, error) {
		for _, key := range keys {
			setOne(tr, key, value)
		}
		return nil, nil
	})
}

func (sm *StackMachine) executeMutation(t fdb.Transactor, f func(fdb.Transaction) (interface{}, error), isDB bool, idx int) {
	_, e := t.Transact(f)
	if e != nil {
		panic(e)
	}
	if isDB {
		sm.store(idx, []byte("RESULT_NOT_PRESENT"))
	}
}

func (dl directoryLayer) Move(t fdb.Transactor, oldPath []string, newPath []string) (DirectorySubspace, error) {
	r, e := t.Transact(func(tr fdb.Transaction) (interface{}, error) {
		if e := dl.checkVersion(tr, &tr); e != nil {
			return nil, e
		}

		sliceEnd := len(oldPath)
		if sliceEnd > len(newPath) {
			sliceEnd = len(newPath)
		}
		if stringsEqual(oldPath, newPath[:sliceEnd]) {
			return nil, errors.New("the destination directory cannot be a subdirectory of the source directory")
		}

		oldNode := dl.find(tr, oldPath).prefetchMetadata(tr)
		newNode := dl.find(tr, newPath).prefetchMetadata(tr)

		if !oldNode.exists() {
			return nil, errors.New("the source directory does not exist")
		}

		if oldNode.isInPartition(nil, false) || newNode.isInPartition(nil, false) {
			if !oldNode.isInPartition(nil, false) || !newNode.isInPartition(nil, false) || !stringsEqual(oldNode.path, newNode.path) {
				return nil, errors.New("cannot move between partitions")
			}

			nnc, e := newNode.getContents(dl, nil)
			if e != nil {
				return nil, e
			}
			return nnc.Move(tr, oldNode.getPartitionSubpath(), newNode.getPartitionSubpath())
		}

		if newNode.exists() {
			return nil, errors.New("the destination directory already exists. Remove it first")
		}

		parentNode := dl.find(tr, newPath[:len(newPath)-1])
		if !parentNode.exists() {
			return nil, errors.New("the parent of the destination directory does not exist. Create it first")
		}

		p, e := dl.nodeSS.Unpack(oldNode.subspace)
		if e != nil {
			return nil, e
		}
		tr.Set(parentNode.subspace.Sub(_SUBDIRS, newPath[len(newPath)-1]), p[0].([]byte))

		dl.removeFromParent(tr, oldPath)

		return dl.contentsOfNode(oldNode.subspace, newPath, oldNode._layer.MustGet())
	})
	if e != nil {
		return nil, e
	}
	return r.(DirectorySubspace), nil
}

func (dl directoryLayer) Create(t fdb.Transactor, path []string, layer []byte) (DirectorySubspace, error) {
	r, e := t.Transact(func(tr fdb.Transaction) (interface{}, error) {
		return dl.createOrOpen(tr, &tr, path, layer, nil, true, false)
	})
	if e != nil {
		return nil, e
	}
	return r.(DirectorySubspace), nil
}

func (dl directoryLayer) Remove(t fdb.Transactor, path []string) (bool, error) {
	r, e := t.Transact(func(tr fdb.Transaction) (interface{}, error) {
		if e := dl.checkVersion(tr, &tr); e != nil {
			return false, e
		}

		if len(path) == 0 {
			return false, errors.New("the root directory cannot be removed")
		}

		node := dl.find(tr, path).prefetchMetadata(tr)

		if !node.exists() {
			return false, nil
		}

		if node.isInPartition(nil, false) {
			nc, e := node.getContents(dl, nil)
			if e != nil {
				return false, e
			}
			return nc.(directoryPartition).Remove(tr, node.getPartitionSubpath())
		}

		if e := dl.removeRecursive(tr, node.subspace); e != nil {
			return false, e
		}
		dl.removeFromParent(tr, path)

		return true, nil
	})
	if e != nil {
		return false, e
	}
	return r.(bool), nil
}

func (de *DirectoryExtension) processOp(sm *StackMachine, op string, isDB bool, idx int, t fdb.Transactor, rt fdb.ReadTransactor) {
	defer func() {
		if r := recover(); r != nil {
			sm.store(idx, []byte("DIRECTORY_ERROR"))
			if createOps[op] {
				de.store(nil)
			}
		}
	}()

	var e error

	switch {
	case op == "CREATE_SUBSPACE":
		tuples := sm.popTuples(1)
		rp := sm.waitAndPop().item.([]byte)
		s := subspace.FromBytes(rp).Sub(tuples[0]...)
		de.store(s)
	case op == "CREATE_LAYER":
		idx1 := sm.waitAndPop().item.(int64)
		idx2 := sm.waitAndPop().item.(int64)
		amp := sm.waitAndPop().item.(int64)
		nodeSS := de.list[idx1]
		contentSS := de.list[idx2]

		if nodeSS == nil || contentSS == nil {
			de.store(nil)
		} else {
			de.store(directory.NewDirectoryLayer(nodeSS.(subspace.Subspace), contentSS.(subspace.Subspace), (amp == int64(1))))
		}
	case op == "CREATE_OR_OPEN":
		tuples := sm.popTuples(1)
		l := sm.waitAndPop().item
		var layer []byte
		if l != nil {
			layer = l.([]byte)
		}
		d, e := de.cwd().CreateOrOpen(t, tupleToPath(tuples[0]), layer)
		if e != nil {
			panic(e)
		}
		de.store(d)
	case op == "CREATE":
		tuples := sm.popTuples(1)
		l := sm.waitAndPop().item
		var layer []byte
		if l != nil {
			layer = l.([]byte)
		}
		p := sm.waitAndPop().item
		var d directory.Directory
		if p == nil {
			d, e = de.cwd().Create(t, tupleToPath(tuples[0]), layer)
		} else {
			// p.([]byte) itself may be nil, but CreatePrefix handles that appropriately
			d, e = de.cwd().CreatePrefix(t, tupleToPath(tuples[0]), layer, p.([]byte))
		}
		if e != nil {
			panic(e)
		}
		de.store(d)
	case op == "OPEN":
		tuples := sm.popTuples(1)
		l := sm.waitAndPop().item
		var layer []byte
		if l != nil {
			layer = l.([]byte)
		}
		d, e := de.cwd().Open(rt, tupleToPath(tuples[0]), layer)
		if e != nil {
			panic(e)
		}
		de.store(d)
	case op == "CHANGE":
		i := sm.waitAndPop().item.(int64)
		if de.list[i] == nil {
			i = de.errorIndex
		}
		de.index = i
	case op == "SET_ERROR_INDEX":
		de.errorIndex = sm.waitAndPop().item.(int64)
	case op == "MOVE":
		tuples := sm.popTuples(2)
		d, e := de.cwd().Move(t, tupleToPath(tuples[0]), tupleToPath(tuples[1]))
		if e != nil {
			panic(e)
		}
		de.store(d)
	case op == "MOVE_TO":
		tuples := sm.popTuples(1)
		d, e := de.cwd().MoveTo(t, tupleToPath(tuples[0]))
		if e != nil {
			panic(e)
		}
		de.store(d)
	case strings.HasPrefix(op, "REMOVE"):
		path := sm.maybePath()
		// This ***HAS*** to call Transact to ensure that any directory version
		// key set in the process of trying to remove this potentially
		// non-existent directory, in the REMOVE but not REMOVE_IF_EXISTS case,
//.........这里部分代码省略.........