/
block_snapshot.go
108 lines (87 loc) · 2.67 KB
/
block_snapshot.go
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// Copyright 2022 Linkall Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package vsb
import (
// standard libraries.
"context"
"encoding/binary"
"sync/atomic"
// this project.
"github.com/vanus-labs/vanus/internal/store/block"
ceschema "github.com/vanus-labs/vanus/internal/store/schema/ce"
"github.com/vanus-labs/vanus/internal/store/vsb/index"
)
// Make sure block implements block.Snapshoter.
var _ block.Snapshoter = (*vsBlock)(nil)
func (b *vsBlock) makeSnapshot() (meta, []index.Index) {
b.mu.RLock()
defer b.mu.RUnlock()
return makeSnapshot(b.actx, b.indexes)
}
func makeSnapshot(actx appendContext, indexes []index.Index) (meta, []index.Index) {
m := meta{
writeOffset: actx.offset,
archived: actx.Archived(),
}
if sz := len(indexes); sz != 0 {
m.entryLength = indexes[sz-1].EndOffset() - indexes[0].StartOffset()
m.entryNum = int64(sz)
}
return m, indexes
}
func (b *vsBlock) Snapshot(_ context.Context) (block.Fragment, error) {
m, _ := b.makeSnapshot()
if m.writeOffset == b.dataOffset {
buf := make([]byte, 8)
binary.LittleEndian.PutUint64(buf, uint64(b.dataOffset))
return block.NewFragment(buf), nil
}
data := make([]byte, m.writeOffset-b.dataOffset+8)
binary.LittleEndian.PutUint64(data, uint64(b.dataOffset))
if _, err := b.f.ReadAt(data[8:], b.dataOffset); err != nil {
return nil, err
}
return block.NewFragment(data), nil
}
func (b *vsBlock) ApplySnapshot(_ context.Context, snap block.Fragment) error {
b.mu.Lock()
defer b.mu.Unlock()
cur := b.actx.offset
so := snap.StartOffset()
if so > cur {
return block.ErrSnapshotOutOfOrder
}
eo := snap.EndOffset()
if eo <= cur {
return nil
}
payload := snap.Payload()
if _, err := b.f.WriteAt(payload[cur-snap.StartOffset():], cur); err != nil {
return err
}
// Build indexes from data.
for off := cur; off < eo; {
n, entry, _ := b.dec.Unmarshal(payload[off-headerBlockSize:])
if ceschema.EntryType(entry) == ceschema.End {
atomic.StoreUint32(&b.actx.archived, 1)
break
}
idx := index.NewIndex(off, int32(n), index.WithEntry(entry))
b.indexes = append(b.indexes, idx)
off += int64(n)
}
b.actx.seq = int64(len(b.indexes))
b.actx.offset = eo
return nil
}