本文整理汇总了Golang中github.com/FoundationDB/fdb-go/fdb.ReadTransaction.Snapshot方法的典型用法代码示例。如果您正苦于以下问题：Golang ReadTransaction.Snapshot方法的具体用法？Golang ReadTransaction.Snapshot怎么用？Golang ReadTransaction.Snapshot使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类github.com/FoundationDB/fdb-go/fdb.ReadTransaction的用法示例。
在下文中一共展示了ReadTransaction.Snapshot方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Golang代码示例。
示例1: createOrOpen
func (dl directoryLayer) createOrOpen(rtr fdb.ReadTransaction, tr *fdb.Transaction, path []string, layer []byte, prefix []byte, allowCreate, allowOpen bool) (DirectorySubspace, error) {
if e := dl.checkVersion(rtr, nil); e != nil {
return nil, e
}
if prefix != nil && !dl.allowManualPrefixes {
if len(dl.path) == 0 {
return nil, errors.New("cannot specify a prefix unless manual prefixes are enabled")
} else {
return nil, errors.New("cannot specify a prefix in a partition")
}
}
if len(path) == 0 {
return nil, errors.New("the root directory cannot be opened")
}
existingNode := dl.find(rtr, path).prefetchMetadata(rtr)
if existingNode.exists() {
if existingNode.isInPartition(nil, false) {
subpath := existingNode.getPartitionSubpath()
enc, e := existingNode.getContents(dl, nil)
if e != nil {
return nil, e
}
return enc.(directoryPartition).createOrOpen(rtr, tr, subpath, layer, prefix, allowCreate, allowOpen)
}
if !allowOpen {
return nil, errors.New("the directory already exists")
}
if layer != nil && bytes.Compare(existingNode._layer.MustGet(), layer) != 0 {
return nil, errors.New("the directory was created with an incompatible layer")
}
return existingNode.getContents(dl, nil)
}
if !allowCreate {
return nil, errors.New("the directory does not exist")
}
if e := dl.checkVersion(rtr, tr); e != nil {
return nil, e
}
if prefix == nil {
newss, e := dl.allocator.allocate(*tr, dl.contentSS)
if e != nil {
return nil, fmt.Errorf("unable to allocate new directory prefix (%s)", e.Error())
}
if !isRangeEmpty(rtr, newss) {
return nil, fmt.Errorf("the database has keys stored at the prefix chosen by the automatic prefix allocator: %v", prefix)
}
prefix = newss.Bytes()
pf, e := dl.isPrefixFree(rtr.Snapshot(), prefix)
if e != nil {
return nil, e
}
if !pf {
return nil, errors.New("the directory layer has manually allocated prefixes that conflict with the automatic prefix allocator")
}
} else {
pf, e := dl.isPrefixFree(rtr, prefix)
if e != nil {
return nil, e
}
if !pf {
return nil, errors.New("the given prefix is already in use")
}
}
var parentNode subspace.Subspace
if len(path) > 1 {
pd, e := dl.createOrOpen(rtr, tr, path[:len(path)-1], nil, nil, true, true)
if e != nil {
return nil, e
}
parentNode = dl.nodeWithPrefix(pd.Bytes())
} else {
parentNode = dl.rootNode
}
if parentNode == nil {
return nil, errors.New("the parent directory does not exist")
}
node := dl.nodeWithPrefix(prefix)
tr.Set(parentNode.Sub(_SUBDIRS, path[len(path)-1]), prefix)
if layer == nil {
layer = []byte{}
}
tr.Set(node.Sub([]byte("layer")), layer)
//.........这里部分代码省略.........