c71116ee94
This PR does two things, because one lead to the other: - Move the leveldb specific stuff into a small "backend" package that defines a backend interface and the leveldb implementation. This allows, potentially, in the future, switching the db implementation so another KV store should we wish to do so. - Add proper error handling all along the way. The db and backend packages are now errcheck clean. However, I drew the line at modifying the FileSet API in order to keep this manageable and not continue refactoring all of the rest of Syncthing. As such, the FileSet methods still panic on database errors, except for the "database is closed" error which is instead handled by silently returning as quickly as possible, with the assumption that we're anyway "on the way out".
71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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package db
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import (
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"encoding/binary"
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"fmt"
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"github.com/syncthing/syncthing/lib/osutil"
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)
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var blockFinder *BlockFinder
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type BlockFinder struct {
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db *instance
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}
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func NewBlockFinder(db *Lowlevel) *BlockFinder {
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if blockFinder != nil {
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return blockFinder
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}
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return &BlockFinder{
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db: newInstance(db),
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}
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}
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func (f *BlockFinder) String() string {
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return fmt.Sprintf("BlockFinder@%p", f)
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}
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// Iterate takes an iterator function which iterates over all matching blocks
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// for the given hash. The iterator function has to return either true (if
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// they are happy with the block) or false to continue iterating for whatever
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// reason. The iterator finally returns the result, whether or not a
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// satisfying block was eventually found.
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func (f *BlockFinder) Iterate(folders []string, hash []byte, iterFn func(string, string, int32) bool) bool {
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t, err := f.db.newReadOnlyTransaction()
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if err != nil {
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return false
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}
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defer t.close()
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var key []byte
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for _, folder := range folders {
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key, err = f.db.keyer.GenerateBlockMapKey(key, []byte(folder), hash, nil)
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if err != nil {
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return false
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}
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iter, err := t.NewPrefixIterator(key)
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if err != nil {
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return false
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}
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for iter.Next() && iter.Error() == nil {
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file := string(f.db.keyer.NameFromBlockMapKey(iter.Key()))
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index := int32(binary.BigEndian.Uint32(iter.Value()))
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if iterFn(folder, osutil.NativeFilename(file), index) {
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iter.Release()
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return true
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}
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}
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iter.Release()
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}
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return false
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}
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