syncthing/lib/db/util.go

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// Copyright (C) 2021 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package db
import "github.com/syncthing/syncthing/lib/protocol"
// How many files to send in each Index/IndexUpdate message.
const (
MaxBatchSizeBytes = 250 * 1024 // Aim for making index messages no larger than 250 KiB (uncompressed)
MaxBatchSizeFiles = 1000 // Either way, don't include more files than this
)
// FileInfoBatch is a utility to do file operations on the database in suitably
// sized batches.
type FileInfoBatch struct {
infos []protocol.FileInfo
size int
flushFn func([]protocol.FileInfo) error
}
func NewFileInfoBatch(fn func([]protocol.FileInfo) error) *FileInfoBatch {
return &FileInfoBatch{
infos: make([]protocol.FileInfo, 0, MaxBatchSizeFiles),
flushFn: fn,
}
}
func (b *FileInfoBatch) SetFlushFunc(fn func([]protocol.FileInfo) error) {
b.flushFn = fn
}
func (b *FileInfoBatch) Append(f protocol.FileInfo) {
b.infos = append(b.infos, f)
b.size += f.ProtoSize()
}
func (b *FileInfoBatch) Full() bool {
return len(b.infos) >= MaxBatchSizeFiles || b.size >= MaxBatchSizeBytes
}
func (b *FileInfoBatch) FlushIfFull() error {
if b.Full() {
return b.Flush()
}
return nil
}
func (b *FileInfoBatch) Flush() error {
if len(b.infos) == 0 {
return nil
}
if err := b.flushFn(b.infos); err != nil {
return err
}
b.Reset()
return nil
}
func (b *FileInfoBatch) Reset() {
b.infos = b.infos[:0]
b.size = 0
}
func (b *FileInfoBatch) Size() int {
return b.size
}