frostfs-node/pkg/local_object_storage/writecache/iterate.go

package writecache

import (
	"errors"
	"fmt"

	"github.com/nspcc-dev/neofs-sdk-go/object"
	"go.etcd.io/bbolt"
)

// ErrNoDefaultBucket is returned by IterateDB when default bucket for objects is missing.
var ErrNoDefaultBucket = errors.New("no default bucket")

// Iterate iterates over all objects present in write cache.
// This is very difficult to do correctly unless write-cache is put in read-only mode.
// Thus we silently fail if shard is not in read-only mode to avoid reporting misleading results.
func (c *cache) Iterate(f func([]byte) error) error {
	c.modeMtx.RLock()
	defer c.modeMtx.RUnlock()
	if c.mode != ModeReadOnly {
		return nil
	}

	err := c.db.View(func(tx *bbolt.Tx) error {
		b := tx.Bucket(defaultBucket)
		return b.ForEach(func(k, data []byte) error {
			if _, ok := c.flushed.Peek(string(k)); ok {
				return nil
			}
			return f(data)
		})
	})
	if err != nil {
		return err
	}

	return c.fsTree.Iterate(func(addr *object.Address, data []byte) error {
		if _, ok := c.flushed.Peek(addr.String()); ok {
			return nil
		}
		return f(data)
	})
}

// IterateDB iterates over all objects stored in bbolt.DB instance and passes them to f until error return.
// It is assumed that db is an underlying database of some WriteCache instance.
//
// Returns ErrNoDefaultBucket if there is no default bucket in db.
//
// DB must not be nil and should be opened.
func IterateDB(db *bbolt.DB, f func(*object.Address) error) error {
	return db.View(func(tx *bbolt.Tx) error {
		b := tx.Bucket(defaultBucket)
		if b == nil {
			return ErrNoDefaultBucket
		}

		var addr *object.Address

		return b.ForEach(func(k, v []byte) error {
			if addr == nil {
				addr = object.NewAddress()
			}

			err := addr.Parse(string(k))
			if err != nil {
				return fmt.Errorf("could not parse object address: %w", err)
			}

			return f(addr)
		})
	})
}