blob: 43beffd93cd86138a47abb904182d527af21ca45 [file] [log] [blame]
// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package memstore
import (
"sync"
"v.io/syncbase/x/ref/services/syncbase/store"
"v.io/v23/verror"
)
type snapshot struct {
mu sync.Mutex
node *store.ResourceNode
data map[string][]byte
err error
}
var _ store.Snapshot = (*snapshot)(nil)
// Assumes st lock is held.
func newSnapshot(st *memstore, parent *store.ResourceNode) *snapshot {
dataCopy := make(map[string][]byte, len(st.data))
for k, v := range st.data {
dataCopy[k] = v
}
s := &snapshot{
node: store.NewResourceNode(),
data: dataCopy,
}
parent.AddChild(s.node, func() {
s.Close()
})
return s
}
// Close implements the store.Snapshot interface.
func (s *snapshot) Close() error {
s.mu.Lock()
defer s.mu.Unlock()
if s.err != nil {
return convertError(s.err)
}
s.node.Close()
s.err = verror.New(verror.ErrCanceled, nil, store.ErrMsgClosedSnapshot)
return nil
}
// Get implements the store.StoreReader interface.
func (s *snapshot) Get(key, valbuf []byte) ([]byte, error) {
s.mu.Lock()
defer s.mu.Unlock()
if s.err != nil {
return valbuf, convertError(s.err)
}
value, ok := s.data[string(key)]
if !ok {
return valbuf, verror.New(store.ErrUnknownKey, nil, string(key))
}
return store.CopyBytes(valbuf, value), nil
}
// Scan implements the store.StoreReader interface.
func (s *snapshot) Scan(start, limit []byte) store.Stream {
s.mu.Lock()
defer s.mu.Unlock()
if s.err != nil {
return &store.InvalidStream{s.err}
}
return newStream(s, s.node, start, limit)
}