fix xsrf and added nonce

vendor/go.etcd.io/bbolt/internal/common/bucket.go

@@ -0,0 +1,54 @@
+package common
+
+import (
+	"fmt"
+	"unsafe"
+)
+
+const BucketHeaderSize = int(unsafe.Sizeof(InBucket{}))
+
+// InBucket represents the on-file representation of a bucket.
+// This is stored as the "value" of a bucket key. If the bucket is small enough,
+// then its root page can be stored inline in the "value", after the bucket
+// header. In the case of inline buckets, the "root" will be 0.
+type InBucket struct {
+	root     Pgid   // page id of the bucket's root-level page
+	sequence uint64 // monotonically incrementing, used by NextSequence()
+}
+
+func NewInBucket(root Pgid, seq uint64) InBucket {
+	return InBucket{
+		root:     root,
+		sequence: seq,
+	}
+}
+
+func (b *InBucket) RootPage() Pgid {
+	return b.root
+}
+
+func (b *InBucket) SetRootPage(id Pgid) {
+	b.root = id
+}
+
+// InSequence returns the sequence. The reason why not naming it `Sequence`
+// is to avoid duplicated name as `(*Bucket) Sequence()`
+func (b *InBucket) InSequence() uint64 {
+	return b.sequence
+}
+
+func (b *InBucket) SetInSequence(v uint64) {
+	b.sequence = v
+}
+
+func (b *InBucket) IncSequence() {
+	b.sequence++
+}
+
+func (b *InBucket) InlinePage(v []byte) *Page {
+	return (*Page)(unsafe.Pointer(&v[BucketHeaderSize]))
+}
+
+func (b *InBucket) String() string {
+	return fmt.Sprintf("<pgid=%d,seq=%d>", b.root, b.sequence)
+}