minio/internal/store/batch.go

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// Copyright (c) 2023 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package store
import (
"errors"
"fmt"
"sync"
)
// ErrBatchFull indicates that the batch is full
var ErrBatchFull = errors.New("batch is full")
type key interface {
string | int | int64
}
// Batch represents an ordered batch
type Batch[K key, T any] struct {
keys []K
items map[K]T
limit uint32
sync.Mutex
}
// Add adds the item to the batch
func (b *Batch[K, T]) Add(key K, item T) error {
b.Lock()
defer b.Unlock()
if b.isFull() {
return ErrBatchFull
}
if _, ok := b.items[key]; !ok {
b.keys = append(b.keys, key)
}
b.items[key] = item
return nil
}
// GetAll fetches the items and resets the batch
// Returned items are not referenced by the batch
func (b *Batch[K, T]) GetAll() (orderedKeys []K, orderedItems []T, err error) {
b.Lock()
defer b.Unlock()
orderedKeys = append([]K(nil), b.keys...)
for _, key := range orderedKeys {
item, ok := b.items[key]
if !ok {
err = fmt.Errorf("item not found for the key: %v; should not happen;", key)
return
}
orderedItems = append(orderedItems, item)
delete(b.items, key)
}
b.keys = b.keys[:0]
return
}
// GetByKey will get the batch item by the provided key
func (b *Batch[K, T]) GetByKey(key K) (T, bool) {
b.Lock()
defer b.Unlock()
item, ok := b.items[key]
return item, ok
}
// Len returns the no of items in the batch
func (b *Batch[K, T]) Len() int {
b.Lock()
defer b.Unlock()
return len(b.keys)
}
// IsFull checks if the batch is full or not
func (b *Batch[K, T]) IsFull() bool {
b.Lock()
defer b.Unlock()
return b.isFull()
}
func (b *Batch[K, T]) isFull() bool {
return len(b.items) >= int(b.limit)
}
// NewBatch creates a new batch
func NewBatch[K key, T any](limit uint32) *Batch[K, T] {
return &Batch[K, T]{
keys: make([]K, 0, limit),
items: make(map[K]T, limit),
limit: limit,
}
}