syncthing/lib/db/blockmap.go

71 lines
1.7 KiB
Go

// Copyright (C) 2014 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 (
"encoding/binary"
"fmt"
"github.com/syncthing/syncthing/lib/osutil"
)
var blockFinder *BlockFinder
type BlockFinder struct {
db *Lowlevel
}
func NewBlockFinder(db *Lowlevel) *BlockFinder {
if blockFinder != nil {
return blockFinder
}
return &BlockFinder{
db: db,
}
}
func (f *BlockFinder) String() string {
return fmt.Sprintf("BlockFinder@%p", f)
}
// Iterate takes an iterator function which iterates over all matching blocks
// for the given hash. The iterator function has to return either true (if
// they are happy with the block) or false to continue iterating for whatever
// reason. The iterator finally returns the result, whether or not a
// satisfying block was eventually found.
func (f *BlockFinder) Iterate(folders []string, hash []byte, iterFn func(string, string, int32) bool) bool {
t, err := f.db.newReadOnlyTransaction()
if err != nil {
return false
}
defer t.close()
var key []byte
for _, folder := range folders {
key, err = f.db.keyer.GenerateBlockMapKey(key, []byte(folder), hash, nil)
if err != nil {
return false
}
iter, err := t.NewPrefixIterator(key)
if err != nil {
return false
}
for iter.Next() && iter.Error() == nil {
file := string(f.db.keyer.NameFromBlockMapKey(iter.Key()))
index := int32(binary.BigEndian.Uint32(iter.Value()))
if iterFn(folder, osutil.NativeFilename(file), index) {
iter.Release()
return true
}
}
iter.Release()
}
return false
}