9f377cde12
There is no need in additional allocations. Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>
150 lines
3.3 KiB
Go
150 lines
3.3 KiB
Go
package storage
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import (
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"strings"
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"sync"
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)
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// MemoryStore is an in-memory implementation of a Store, mainly
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// used for testing. Do not use MemoryStore in production.
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type MemoryStore struct {
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mut sync.RWMutex
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mem map[string][]byte
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// A map, not a slice, to avoid duplicates.
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del map[string]bool
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}
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// MemoryBatch is an in-memory batch compatible with MemoryStore.
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type MemoryBatch struct {
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MemoryStore
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}
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// Put implements the Batch interface.
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func (b *MemoryBatch) Put(k, v []byte) {
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_ = b.MemoryStore.Put(k, v)
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}
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// Delete implements Batch interface.
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func (b *MemoryBatch) Delete(k []byte) {
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_ = b.MemoryStore.Delete(k)
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}
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// NewMemoryStore creates a new MemoryStore object.
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func NewMemoryStore() *MemoryStore {
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return &MemoryStore{
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mem: make(map[string][]byte),
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del: make(map[string]bool),
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}
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}
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// Get implements the Store interface.
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func (s *MemoryStore) Get(key []byte) ([]byte, error) {
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s.mut.RLock()
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defer s.mut.RUnlock()
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if val, ok := s.mem[string(key)]; ok {
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return val, nil
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}
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return nil, ErrKeyNotFound
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}
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// put puts a key-value pair into the store, it's supposed to be called
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// with mutex locked.
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func (s *MemoryStore) put(key string, value []byte) {
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s.mem[key] = value
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delete(s.del, key)
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}
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// Put implements the Store interface. Never returns an error.
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func (s *MemoryStore) Put(key, value []byte) error {
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newKey := string(key)
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vcopy := make([]byte, len(value))
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copy(vcopy, value)
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s.mut.Lock()
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s.put(newKey, vcopy)
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s.mut.Unlock()
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return nil
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}
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// drop deletes a key-value pair from the store, it's supposed to be called
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// with mutex locked.
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func (s *MemoryStore) drop(key string) {
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s.del[key] = true
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delete(s.mem, key)
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}
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// Delete implements Store interface. Never returns an error.
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func (s *MemoryStore) Delete(key []byte) error {
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newKey := string(key)
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s.mut.Lock()
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s.drop(newKey)
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s.mut.Unlock()
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return nil
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}
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// PutBatch implements the Store interface. Never returns an error.
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func (s *MemoryStore) PutBatch(batch Batch) error {
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b := batch.(*MemoryBatch)
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s.mut.Lock()
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defer s.mut.Unlock()
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for k := range b.del {
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s.drop(k)
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}
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for k, v := range b.mem {
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s.put(k, v)
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}
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return nil
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}
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// Seek implements the Store interface.
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func (s *MemoryStore) Seek(key []byte, f func(k, v []byte)) {
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s.mut.RLock()
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s.seek(key, f)
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s.mut.RUnlock()
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}
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// SeekAll is like seek but also iterates over deleted items.
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func (s *MemoryStore) SeekAll(key []byte, f func(k, v []byte)) {
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s.mut.RLock()
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defer s.mut.RUnlock()
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sk := string(key)
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for k, v := range s.mem {
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if strings.HasPrefix(k, sk) {
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f([]byte(k), v)
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}
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}
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for k := range s.del {
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if strings.HasPrefix(k, sk) {
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f([]byte(k), nil)
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}
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}
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}
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// seek is an internal unlocked implementation of Seek.
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func (s *MemoryStore) seek(key []byte, f func(k, v []byte)) {
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sk := string(key)
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for k, v := range s.mem {
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if strings.HasPrefix(k, sk) {
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f([]byte(k), v)
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}
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}
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}
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// Batch implements the Batch interface and returns a compatible Batch.
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func (s *MemoryStore) Batch() Batch {
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return newMemoryBatch()
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}
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// newMemoryBatch returns new memory batch.
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func newMemoryBatch() *MemoryBatch {
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return &MemoryBatch{MemoryStore: *NewMemoryStore()}
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}
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// Close implements Store interface and clears up memory. Never returns an
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// error.
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func (s *MemoryStore) Close() error {
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s.mut.Lock()
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s.del = nil
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s.mem = nil
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s.mut.Unlock()
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return nil
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}
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