forked from keybase/client
/
indexed_tlf_db.go
223 lines (199 loc) · 5.48 KB
/
indexed_tlf_db.go
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// Copyright 2019 Keybase Inc. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.
package search
import (
"context"
"io"
"path/filepath"
"sync"
"github.com/keybase/client/go/kbfs/kbfsmd"
"github.com/keybase/client/go/kbfs/ldbutils"
"github.com/keybase/client/go/kbfs/libkbfs"
"github.com/keybase/client/go/kbfs/tlf"
"github.com/keybase/client/go/logger"
"github.com/pkg/errors"
"github.com/syndtr/goleveldb/leveldb/storage"
)
const (
initialIndexedTlfsDbVersion uint64 = 1
currentIndexedTlfsDbVersion uint64 = initialIndexedTlfsDbVersion
indexedTlfsFolderName string = "indexed_tlfs"
)
// IndexedTlfDb is a database that holds metadata about indexed TLFs.
type IndexedTlfDb struct {
config libkbfs.Config
log logger.Logger
// Protect the DB from being shutdown while they're being
// accessed, and mutable data.
lock sync.RWMutex
tlfDb *ldbutils.LevelDb // tlfID -> TLF metadata.
shutdownCh chan struct{}
closer func()
}
// newIndexedTlfDbFromStorage creates a new *IndexedTlfDb with the
// passed-in storage.Storage interfaces as a storage layers for the db.
func newIndexedTlfDbFromStorage(
config libkbfs.Config, tlfStorage storage.Storage) (
db *IndexedTlfDb, err error) {
log := config.MakeLogger("ITD")
closers := make([]io.Closer, 0, 1)
closer := func() {
for _, c := range closers {
closeErr := c.Close()
if closeErr != nil {
log.Warning("Error closing leveldb or storage: %+v", closeErr)
}
}
}
defer func() {
if err != nil {
err = errors.WithStack(err)
closer()
}
}()
tlfDbOptions := ldbutils.LeveldbOptions(config.Mode())
tlfDb, err := ldbutils.OpenLevelDbWithOptions(tlfStorage, tlfDbOptions)
if err != nil {
return nil, err
}
closers = append(closers, tlfDb)
return &IndexedTlfDb{
config: config,
tlfDb: tlfDb,
shutdownCh: make(chan struct{}),
closer: closer,
}, nil
}
// newIndexedTlfDb creates a new *IndexedTlfDb with a
// specified directory on the filesystem as storage.
func newIndexedTlfDb(config libkbfs.Config, dirPath string) (
db *IndexedTlfDb, err error) {
log := config.MakeLogger("ITD")
defer func() {
if err != nil {
log.Error("Error initializing indexed TLF db: %+v", err)
}
}()
dbPath := filepath.Join(dirPath, indexedTlfsFolderName)
versionPath, err := ldbutils.GetVersionedPathForDb(
log, dbPath, "indexed TLFs", currentIndexedTlfsDbVersion)
if err != nil {
return nil, err
}
tlfDbPath := filepath.Join(versionPath, tlfDbFilename)
tlfStorage, err := storage.OpenFile(tlfDbPath, false)
if err != nil {
return nil, err
}
defer func() {
if err != nil {
tlfStorage.Close()
}
}()
return newIndexedTlfDbFromStorage(config, tlfStorage)
}
type tlfMD struct {
// Exported only for serialization.
IndexedRevision kbfsmd.Revision `codec:"i"`
StartedRevision kbfsmd.Revision `codec:"s"`
}
// getMetadataLocked retrieves the metadata for a block in the db, or
// returns leveldb.ErrNotFound and a zero-valued metadata otherwise.
func (db *IndexedTlfDb) getMetadataLocked(tlfID tlf.ID) (
metadata tlfMD, err error) {
metadataBytes, err := db.tlfDb.Get(tlfID.Bytes(), nil)
if err != nil {
return tlfMD{}, err
}
err = db.config.Codec().Decode(metadataBytes, &metadata)
if err != nil {
return tlfMD{}, err
}
return metadata, nil
}
// checkAndLockDb checks whether the db is started.
func (db *IndexedTlfDb) checkDbLocked(
ctx context.Context, method string) error {
// First see if the context has expired since we began.
select {
case <-ctx.Done():
return ctx.Err()
default:
}
// shutdownCh has to be checked under lock, otherwise we can race.
select {
case <-db.shutdownCh:
return errors.WithStack(DbClosedError{method})
default:
}
if db.tlfDb == nil {
return errors.WithStack(DbClosedError{method})
}
return nil
}
// Get returns the revisions for the given TLF.
func (db *IndexedTlfDb) Get(
ctx context.Context, tlfID tlf.ID) (
indexedRev, startedRev kbfsmd.Revision, err error) {
db.lock.RLock()
defer db.lock.RUnlock()
err = db.checkDbLocked(ctx, "ITD(Get)")
if err != nil {
return kbfsmd.RevisionUninitialized, kbfsmd.RevisionUninitialized, err
}
md, err := db.getMetadataLocked(tlfID)
if err != nil {
return kbfsmd.RevisionUninitialized, kbfsmd.RevisionUninitialized, err
}
return md.IndexedRevision, md.StartedRevision, nil
}
// Put saves the revisions for the given TLF.
func (db *IndexedTlfDb) Put(
ctx context.Context, tlfID tlf.ID,
indexedRev, startedRev kbfsmd.Revision) error {
db.lock.Lock()
defer db.lock.Unlock()
err := db.checkDbLocked(ctx, "ITD(Put)")
if err != nil {
return err
}
md := tlfMD{
IndexedRevision: indexedRev,
StartedRevision: startedRev,
}
encodedMetadata, err := db.config.Codec().Encode(&md)
if err != nil {
return err
}
return db.tlfDb.Put(tlfID.Bytes(), encodedMetadata, nil)
}
// Delete removes the metadata for the TLF from the DB.
func (db *IndexedTlfDb) Delete(
ctx context.Context, tlfID tlf.ID) error {
db.lock.Lock()
defer db.lock.Unlock()
err := db.checkDbLocked(ctx, "ITD(Delete)")
if err != nil {
return err
}
return db.tlfDb.Delete(tlfID.Bytes(), nil)
}
// Shutdown closes this db.
func (db *IndexedTlfDb) Shutdown(ctx context.Context) {
db.lock.Lock()
defer db.lock.Unlock()
// shutdownCh has to be checked under lock, otherwise we can race.
select {
case <-db.shutdownCh:
db.log.CWarningf(ctx, "Shutdown called more than once")
return
default:
}
close(db.shutdownCh)
if db.tlfDb == nil {
return
}
db.closer()
db.tlfDb = nil
}