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-rw-r--r--vendor/github.com/syndtr/goleveldb/leveldb/db.go1098
1 files changed, 1098 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db.go b/vendor/github.com/syndtr/goleveldb/leveldb/db.go
new file mode 100644
index 0000000..ea5595e
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db.go
@@ -0,0 +1,1098 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+ "container/list"
+ "fmt"
+ "io"
+ "os"
+ "runtime"
+ "strings"
+ "sync"
+ "sync/atomic"
+ "time"
+
+ "github.com/syndtr/goleveldb/leveldb/errors"
+ "github.com/syndtr/goleveldb/leveldb/iterator"
+ "github.com/syndtr/goleveldb/leveldb/journal"
+ "github.com/syndtr/goleveldb/leveldb/memdb"
+ "github.com/syndtr/goleveldb/leveldb/opt"
+ "github.com/syndtr/goleveldb/leveldb/storage"
+ "github.com/syndtr/goleveldb/leveldb/table"
+ "github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// DB is a LevelDB database.
+type DB struct {
+ // Need 64-bit alignment.
+ seq uint64
+
+ // Stats. Need 64-bit alignment.
+ cWriteDelay int64 // The cumulative duration of write delays
+ cWriteDelayN int32 // The cumulative number of write delays
+ aliveSnaps, aliveIters int32
+
+ // Session.
+ s *session
+
+ // MemDB.
+ memMu sync.RWMutex
+ memPool chan *memdb.DB
+ mem, frozenMem *memDB
+ journal *journal.Writer
+ journalWriter storage.Writer
+ journalFd storage.FileDesc
+ frozenJournalFd storage.FileDesc
+ frozenSeq uint64
+
+ // Snapshot.
+ snapsMu sync.Mutex
+ snapsList *list.List
+
+ // Write.
+ batchPool sync.Pool
+ writeMergeC chan writeMerge
+ writeMergedC chan bool
+ writeLockC chan struct{}
+ writeAckC chan error
+ writeDelay time.Duration
+ writeDelayN int
+ tr *Transaction
+
+ // Compaction.
+ compCommitLk sync.Mutex
+ tcompCmdC chan cCmd
+ tcompPauseC chan chan<- struct{}
+ mcompCmdC chan cCmd
+ compErrC chan error
+ compPerErrC chan error
+ compErrSetC chan error
+ compWriteLocking bool
+ compStats cStats
+ memdbMaxLevel int // For testing.
+
+ // Close.
+ closeW sync.WaitGroup
+ closeC chan struct{}
+ closed uint32
+ closer io.Closer
+}
+
+func openDB(s *session) (*DB, error) {
+ s.log("db@open opening")
+ start := time.Now()
+ db := &DB{
+ s: s,
+ // Initial sequence
+ seq: s.stSeqNum,
+ // MemDB
+ memPool: make(chan *memdb.DB, 1),
+ // Snapshot
+ snapsList: list.New(),
+ // Write
+ batchPool: sync.Pool{New: newBatch},
+ writeMergeC: make(chan writeMerge),
+ writeMergedC: make(chan bool),
+ writeLockC: make(chan struct{}, 1),
+ writeAckC: make(chan error),
+ // Compaction
+ tcompCmdC: make(chan cCmd),
+ tcompPauseC: make(chan chan<- struct{}),
+ mcompCmdC: make(chan cCmd),
+ compErrC: make(chan error),
+ compPerErrC: make(chan error),
+ compErrSetC: make(chan error),
+ // Close
+ closeC: make(chan struct{}),
+ }
+
+ // Read-only mode.
+ readOnly := s.o.GetReadOnly()
+
+ if readOnly {
+ // Recover journals (read-only mode).
+ if err := db.recoverJournalRO(); err != nil {
+ return nil, err
+ }
+ } else {
+ // Recover journals.
+ if err := db.recoverJournal(); err != nil {
+ return nil, err
+ }
+
+ // Remove any obsolete files.
+ if err := db.checkAndCleanFiles(); err != nil {
+ // Close journal.
+ if db.journal != nil {
+ db.journal.Close()
+ db.journalWriter.Close()
+ }
+ return nil, err
+ }
+
+ }
+
+ // Doesn't need to be included in the wait group.
+ go db.compactionError()
+ go db.mpoolDrain()
+
+ if readOnly {
+ db.SetReadOnly()
+ } else {
+ db.closeW.Add(2)
+ go db.tCompaction()
+ go db.mCompaction()
+ // go db.jWriter()
+ }
+
+ s.logf("db@open done T·%v", time.Since(start))
+
+ runtime.SetFinalizer(db, (*DB).Close)
+ return db, nil
+}
+
+// Open opens or creates a DB for the given storage.
+// The DB will be created if not exist, unless ErrorIfMissing is true.
+// Also, if ErrorIfExist is true and the DB exist Open will returns
+// os.ErrExist error.
+//
+// Open will return an error with type of ErrCorrupted if corruption
+// detected in the DB. Use errors.IsCorrupted to test whether an error is
+// due to corruption. Corrupted DB can be recovered with Recover function.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func Open(stor storage.Storage, o *opt.Options) (db *DB, err error) {
+ s, err := newSession(stor, o)
+ if err != nil {
+ return
+ }
+ defer func() {
+ if err != nil {
+ s.close()
+ s.release()
+ }
+ }()
+
+ err = s.recover()
+ if err != nil {
+ if !os.IsNotExist(err) || s.o.GetErrorIfMissing() {
+ return
+ }
+ err = s.create()
+ if err != nil {
+ return
+ }
+ } else if s.o.GetErrorIfExist() {
+ err = os.ErrExist
+ return
+ }
+
+ return openDB(s)
+}
+
+// OpenFile opens or creates a DB for the given path.
+// The DB will be created if not exist, unless ErrorIfMissing is true.
+// Also, if ErrorIfExist is true and the DB exist OpenFile will returns
+// os.ErrExist error.
+//
+// OpenFile uses standard file-system backed storage implementation as
+// described in the leveldb/storage package.
+//
+// OpenFile will return an error with type of ErrCorrupted if corruption
+// detected in the DB. Use errors.IsCorrupted to test whether an error is
+// due to corruption. Corrupted DB can be recovered with Recover function.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func OpenFile(path string, o *opt.Options) (db *DB, err error) {
+ stor, err := storage.OpenFile(path, o.GetReadOnly())
+ if err != nil {
+ return
+ }
+ db, err = Open(stor, o)
+ if err != nil {
+ stor.Close()
+ } else {
+ db.closer = stor
+ }
+ return
+}
+
+// Recover recovers and opens a DB with missing or corrupted manifest files
+// for the given storage. It will ignore any manifest files, valid or not.
+// The DB must already exist or it will returns an error.
+// Also, Recover will ignore ErrorIfMissing and ErrorIfExist options.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func Recover(stor storage.Storage, o *opt.Options) (db *DB, err error) {
+ s, err := newSession(stor, o)
+ if err != nil {
+ return
+ }
+ defer func() {
+ if err != nil {
+ s.close()
+ s.release()
+ }
+ }()
+
+ err = recoverTable(s, o)
+ if err != nil {
+ return
+ }
+ return openDB(s)
+}
+
+// RecoverFile recovers and opens a DB with missing or corrupted manifest files
+// for the given path. It will ignore any manifest files, valid or not.
+// The DB must already exist or it will returns an error.
+// Also, Recover will ignore ErrorIfMissing and ErrorIfExist options.
+//
+// RecoverFile uses standard file-system backed storage implementation as described
+// in the leveldb/storage package.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func RecoverFile(path string, o *opt.Options) (db *DB, err error) {
+ stor, err := storage.OpenFile(path, false)
+ if err != nil {
+ return
+ }
+ db, err = Recover(stor, o)
+ if err != nil {
+ stor.Close()
+ } else {
+ db.closer = stor
+ }
+ return
+}
+
+func recoverTable(s *session, o *opt.Options) error {
+ o = dupOptions(o)
+ // Mask StrictReader, lets StrictRecovery doing its job.
+ o.Strict &= ^opt.StrictReader
+
+ // Get all tables and sort it by file number.
+ fds, err := s.stor.List(storage.TypeTable)
+ if err != nil {
+ return err
+ }
+ sortFds(fds)
+
+ var (
+ maxSeq uint64
+ recoveredKey, goodKey, corruptedKey, corruptedBlock, droppedTable int
+
+ // We will drop corrupted table.
+ strict = o.GetStrict(opt.StrictRecovery)
+ noSync = o.GetNoSync()
+
+ rec = &sessionRecord{}
+ bpool = util.NewBufferPool(o.GetBlockSize() + 5)
+ )
+ buildTable := func(iter iterator.Iterator) (tmpFd storage.FileDesc, size int64, err error) {
+ tmpFd = s.newTemp()
+ writer, err := s.stor.Create(tmpFd)
+ if err != nil {
+ return
+ }
+ defer func() {
+ writer.Close()
+ if err != nil {
+ s.stor.Remove(tmpFd)
+ tmpFd = storage.FileDesc{}
+ }
+ }()
+
+ // Copy entries.
+ tw := table.NewWriter(writer, o)
+ for iter.Next() {
+ key := iter.Key()
+ if validInternalKey(key) {
+ err = tw.Append(key, iter.Value())
+ if err != nil {
+ return
+ }
+ }
+ }
+ err = iter.Error()
+ if err != nil && !errors.IsCorrupted(err) {
+ return
+ }
+ err = tw.Close()
+ if err != nil {
+ return
+ }
+ if !noSync {
+ err = writer.Sync()
+ if err != nil {
+ return
+ }
+ }
+ size = int64(tw.BytesLen())
+ return
+ }
+ recoverTable := func(fd storage.FileDesc) error {
+ s.logf("table@recovery recovering @%d", fd.Num)
+ reader, err := s.stor.Open(fd)
+ if err != nil {
+ return err
+ }
+ var closed bool
+ defer func() {
+ if !closed {
+ reader.Close()
+ }
+ }()
+
+ // Get file size.
+ size, err := reader.Seek(0, 2)
+ if err != nil {
+ return err
+ }
+
+ var (
+ tSeq uint64
+ tgoodKey, tcorruptedKey, tcorruptedBlock int
+ imin, imax []byte
+ )
+ tr, err := table.NewReader(reader, size, fd, nil, bpool, o)
+ if err != nil {
+ return err
+ }
+ iter := tr.NewIterator(nil, nil)
+ if itererr, ok := iter.(iterator.ErrorCallbackSetter); ok {
+ itererr.SetErrorCallback(func(err error) {
+ if errors.IsCorrupted(err) {
+ s.logf("table@recovery block corruption @%d %q", fd.Num, err)
+ tcorruptedBlock++
+ }
+ })
+ }
+
+ // Scan the table.
+ for iter.Next() {
+ key := iter.Key()
+ _, seq, _, kerr := parseInternalKey(key)
+ if kerr != nil {
+ tcorruptedKey++
+ continue
+ }
+ tgoodKey++
+ if seq > tSeq {
+ tSeq = seq
+ }
+ if imin == nil {
+ imin = append([]byte{}, key...)
+ }
+ imax = append(imax[:0], key...)
+ }
+ if err := iter.Error(); err != nil && !errors.IsCorrupted(err) {
+ iter.Release()
+ return err
+ }
+ iter.Release()
+
+ goodKey += tgoodKey
+ corruptedKey += tcorruptedKey
+ corruptedBlock += tcorruptedBlock
+
+ if strict && (tcorruptedKey > 0 || tcorruptedBlock > 0) {
+ droppedTable++
+ s.logf("table@recovery dropped @%d Gk·%d Ck·%d Cb·%d S·%d Q·%d", fd.Num, tgoodKey, tcorruptedKey, tcorruptedBlock, size, tSeq)
+ return nil
+ }
+
+ if tgoodKey > 0 {
+ if tcorruptedKey > 0 || tcorruptedBlock > 0 {
+ // Rebuild the table.
+ s.logf("table@recovery rebuilding @%d", fd.Num)
+ iter := tr.NewIterator(nil, nil)
+ tmpFd, newSize, err := buildTable(iter)
+ iter.Release()
+ if err != nil {
+ return err
+ }
+ closed = true
+ reader.Close()
+ if err := s.stor.Rename(tmpFd, fd); err != nil {
+ return err
+ }
+ size = newSize
+ }
+ if tSeq > maxSeq {
+ maxSeq = tSeq
+ }
+ recoveredKey += tgoodKey
+ // Add table to level 0.
+ rec.addTable(0, fd.Num, size, imin, imax)
+ s.logf("table@recovery recovered @%d Gk·%d Ck·%d Cb·%d S·%d Q·%d", fd.Num, tgoodKey, tcorruptedKey, tcorruptedBlock, size, tSeq)
+ } else {
+ droppedTable++
+ s.logf("table@recovery unrecoverable @%d Ck·%d Cb·%d S·%d", fd.Num, tcorruptedKey, tcorruptedBlock, size)
+ }
+
+ return nil
+ }
+
+ // Recover all tables.
+ if len(fds) > 0 {
+ s.logf("table@recovery F·%d", len(fds))
+
+ // Mark file number as used.
+ s.markFileNum(fds[len(fds)-1].Num)
+
+ for _, fd := range fds {
+ if err := recoverTable(fd); err != nil {
+ return err
+ }
+ }
+
+ s.logf("table@recovery recovered F·%d N·%d Gk·%d Ck·%d Q·%d", len(fds), recoveredKey, goodKey, corruptedKey, maxSeq)
+ }
+
+ // Set sequence number.
+ rec.setSeqNum(maxSeq)
+
+ // Create new manifest.
+ if err := s.create(); err != nil {
+ return err
+ }
+
+ // Commit.
+ return s.commit(rec)
+}
+
+func (db *DB) recoverJournal() error {
+ // Get all journals and sort it by file number.
+ rawFds, err := db.s.stor.List(storage.TypeJournal)
+ if err != nil {
+ return err
+ }
+ sortFds(rawFds)
+
+ // Journals that will be recovered.
+ var fds []storage.FileDesc
+ for _, fd := range rawFds {
+ if fd.Num >= db.s.stJournalNum || fd.Num == db.s.stPrevJournalNum {
+ fds = append(fds, fd)
+ }
+ }
+
+ var (
+ ofd storage.FileDesc // Obsolete file.
+ rec = &sessionRecord{}
+ )
+
+ // Recover journals.
+ if len(fds) > 0 {
+ db.logf("journal@recovery F·%d", len(fds))
+
+ // Mark file number as used.
+ db.s.markFileNum(fds[len(fds)-1].Num)
+
+ var (
+ // Options.
+ strict = db.s.o.GetStrict(opt.StrictJournal)
+ checksum = db.s.o.GetStrict(opt.StrictJournalChecksum)
+ writeBuffer = db.s.o.GetWriteBuffer()
+
+ jr *journal.Reader
+ mdb = memdb.New(db.s.icmp, writeBuffer)
+ buf = &util.Buffer{}
+ batchSeq uint64
+ batchLen int
+ )
+
+ for _, fd := range fds {
+ db.logf("journal@recovery recovering @%d", fd.Num)
+
+ fr, err := db.s.stor.Open(fd)
+ if err != nil {
+ return err
+ }
+
+ // Create or reset journal reader instance.
+ if jr == nil {
+ jr = journal.NewReader(fr, dropper{db.s, fd}, strict, checksum)
+ } else {
+ jr.Reset(fr, dropper{db.s, fd}, strict, checksum)
+ }
+
+ // Flush memdb and remove obsolete journal file.
+ if !ofd.Zero() {
+ if mdb.Len() > 0 {
+ if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
+ fr.Close()
+ return err
+ }
+ }
+
+ rec.setJournalNum(fd.Num)
+ rec.setSeqNum(db.seq)
+ if err := db.s.commit(rec); err != nil {
+ fr.Close()
+ return err
+ }
+ rec.resetAddedTables()
+
+ db.s.stor.Remove(ofd)
+ ofd = storage.FileDesc{}
+ }
+
+ // Replay journal to memdb.
+ mdb.Reset()
+ for {
+ r, err := jr.Next()
+ if err != nil {
+ if err == io.EOF {
+ break
+ }
+
+ fr.Close()
+ return errors.SetFd(err, fd)
+ }
+
+ buf.Reset()
+ if _, err := buf.ReadFrom(r); err != nil {
+ if err == io.ErrUnexpectedEOF {
+ // This is error returned due to corruption, with strict == false.
+ continue
+ }
+
+ fr.Close()
+ return errors.SetFd(err, fd)
+ }
+ batchSeq, batchLen, err = decodeBatchToMem(buf.Bytes(), db.seq, mdb)
+ if err != nil {
+ if !strict && errors.IsCorrupted(err) {
+ db.s.logf("journal error: %v (skipped)", err)
+ // We won't apply sequence number as it might be corrupted.
+ continue
+ }
+
+ fr.Close()
+ return errors.SetFd(err, fd)
+ }
+
+ // Save sequence number.
+ db.seq = batchSeq + uint64(batchLen)
+
+ // Flush it if large enough.
+ if mdb.Size() >= writeBuffer {
+ if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
+ fr.Close()
+ return err
+ }
+
+ mdb.Reset()
+ }
+ }
+
+ fr.Close()
+ ofd = fd
+ }
+
+ // Flush the last memdb.
+ if mdb.Len() > 0 {
+ if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
+ return err
+ }
+ }
+ }
+
+ // Create a new journal.
+ if _, err := db.newMem(0); err != nil {
+ return err
+ }
+
+ // Commit.
+ rec.setJournalNum(db.journalFd.Num)
+ rec.setSeqNum(db.seq)
+ if err := db.s.commit(rec); err != nil {
+ // Close journal on error.
+ if db.journal != nil {
+ db.journal.Close()
+ db.journalWriter.Close()
+ }
+ return err
+ }
+
+ // Remove the last obsolete journal file.
+ if !ofd.Zero() {
+ db.s.stor.Remove(ofd)
+ }
+
+ return nil
+}
+
+func (db *DB) recoverJournalRO() error {
+ // Get all journals and sort it by file number.
+ rawFds, err := db.s.stor.List(storage.TypeJournal)
+ if err != nil {
+ return err
+ }
+ sortFds(rawFds)
+
+ // Journals that will be recovered.
+ var fds []storage.FileDesc
+ for _, fd := range rawFds {
+ if fd.Num >= db.s.stJournalNum || fd.Num == db.s.stPrevJournalNum {
+ fds = append(fds, fd)
+ }
+ }
+
+ var (
+ // Options.
+ strict = db.s.o.GetStrict(opt.StrictJournal)
+ checksum = db.s.o.GetStrict(opt.StrictJournalChecksum)
+ writeBuffer = db.s.o.GetWriteBuffer()
+
+ mdb = memdb.New(db.s.icmp, writeBuffer)
+ )
+
+ // Recover journals.
+ if len(fds) > 0 {
+ db.logf("journal@recovery RO·Mode F·%d", len(fds))
+
+ var (
+ jr *journal.Reader
+ buf = &util.Buffer{}
+ batchSeq uint64
+ batchLen int
+ )
+
+ for _, fd := range fds {
+ db.logf("journal@recovery recovering @%d", fd.Num)
+
+ fr, err := db.s.stor.Open(fd)
+ if err != nil {
+ return err
+ }
+
+ // Create or reset journal reader instance.
+ if jr == nil {
+ jr = journal.NewReader(fr, dropper{db.s, fd}, strict, checksum)
+ } else {
+ jr.Reset(fr, dropper{db.s, fd}, strict, checksum)
+ }
+
+ // Replay journal to memdb.
+ for {
+ r, err := jr.Next()
+ if err != nil {
+ if err == io.EOF {
+ break
+ }
+
+ fr.Close()
+ return errors.SetFd(err, fd)
+ }
+
+ buf.Reset()
+ if _, err := buf.ReadFrom(r); err != nil {
+ if err == io.ErrUnexpectedEOF {
+ // This is error returned due to corruption, with strict == false.
+ continue
+ }
+
+ fr.Close()
+ return errors.SetFd(err, fd)
+ }
+ batchSeq, batchLen, err = decodeBatchToMem(buf.Bytes(), db.seq, mdb)
+ if err != nil {
+ if !strict && errors.IsCorrupted(err) {
+ db.s.logf("journal error: %v (skipped)", err)
+ // We won't apply sequence number as it might be corrupted.
+ continue
+ }
+
+ fr.Close()
+ return errors.SetFd(err, fd)
+ }
+
+ // Save sequence number.
+ db.seq = batchSeq + uint64(batchLen)
+ }
+
+ fr.Close()
+ }
+ }
+
+ // Set memDB.
+ db.mem = &memDB{db: db, DB: mdb, ref: 1}
+
+ return nil
+}
+
+func memGet(mdb *memdb.DB, ikey internalKey, icmp *iComparer) (ok bool, mv []byte, err error) {
+ mk, mv, err := mdb.Find(ikey)
+ if err == nil {
+ ukey, _, kt, kerr := parseInternalKey(mk)
+ if kerr != nil {
+ // Shouldn't have had happen.
+ panic(kerr)
+ }
+ if icmp.uCompare(ukey, ikey.ukey()) == 0 {
+ if kt == keyTypeDel {
+ return true, nil, ErrNotFound
+ }
+ return true, mv, nil
+
+ }
+ } else if err != ErrNotFound {
+ return true, nil, err
+ }
+ return
+}
+
+func (db *DB) get(auxm *memdb.DB, auxt tFiles, key []byte, seq uint64, ro *opt.ReadOptions) (value []byte, err error) {
+ ikey := makeInternalKey(nil, key, seq, keyTypeSeek)
+
+ if auxm != nil {
+ if ok, mv, me := memGet(auxm, ikey, db.s.icmp); ok {
+ return append([]byte{}, mv...), me
+ }
+ }
+
+ em, fm := db.getMems()
+ for _, m := range [...]*memDB{em, fm} {
+ if m == nil {
+ continue
+ }
+ defer m.decref()
+
+ if ok, mv, me := memGet(m.DB, ikey, db.s.icmp); ok {
+ return append([]byte{}, mv...), me
+ }
+ }
+
+ v := db.s.version()
+ value, cSched, err := v.get(auxt, ikey, ro, false)
+ v.release()
+ if cSched {
+ // Trigger table compaction.
+ db.compTrigger(db.tcompCmdC)
+ }
+ return
+}
+
+func nilIfNotFound(err error) error {
+ if err == ErrNotFound {
+ return nil
+ }
+ return err
+}
+
+func (db *DB) has(auxm *memdb.DB, auxt tFiles, key []byte, seq uint64, ro *opt.ReadOptions) (ret bool, err error) {
+ ikey := makeInternalKey(nil, key, seq, keyTypeSeek)
+
+ if auxm != nil {
+ if ok, _, me := memGet(auxm, ikey, db.s.icmp); ok {
+ return me == nil, nilIfNotFound(me)
+ }
+ }
+
+ em, fm := db.getMems()
+ for _, m := range [...]*memDB{em, fm} {
+ if m == nil {
+ continue
+ }
+ defer m.decref()
+
+ if ok, _, me := memGet(m.DB, ikey, db.s.icmp); ok {
+ return me == nil, nilIfNotFound(me)
+ }
+ }
+
+ v := db.s.version()
+ _, cSched, err := v.get(auxt, ikey, ro, true)
+ v.release()
+ if cSched {
+ // Trigger table compaction.
+ db.compTrigger(db.tcompCmdC)
+ }
+ if err == nil {
+ ret = true
+ } else if err == ErrNotFound {
+ err = nil
+ }
+ return
+}
+
+// Get gets the value for the given key. It returns ErrNotFound if the
+// DB does not contains the key.
+//
+// The returned slice is its own copy, it is safe to modify the contents
+// of the returned slice.
+// It is safe to modify the contents of the argument after Get returns.
+func (db *DB) Get(key []byte, ro *opt.ReadOptions) (value []byte, err error) {
+ err = db.ok()
+ if err != nil {
+ return
+ }
+
+ se := db.acquireSnapshot()
+ defer db.releaseSnapshot(se)
+ return db.get(nil, nil, key, se.seq, ro)
+}
+
+// Has returns true if the DB does contains the given key.
+//
+// It is safe to modify the contents of the argument after Has returns.
+func (db *DB) Has(key []byte, ro *opt.ReadOptions) (ret bool, err error) {
+ err = db.ok()
+ if err != nil {
+ return
+ }
+
+ se := db.acquireSnapshot()
+ defer db.releaseSnapshot(se)
+ return db.has(nil, nil, key, se.seq, ro)
+}
+
+// NewIterator returns an iterator for the latest snapshot of the
+// underlying DB.
+// The returned iterator is not safe for concurrent use, but it is safe to use
+// multiple iterators concurrently, with each in a dedicated goroutine.
+// It is also safe to use an iterator concurrently with modifying its
+// underlying DB. The resultant key/value pairs are guaranteed to be
+// consistent.
+//
+// Slice allows slicing the iterator to only contains keys in the given
+// range. A nil Range.Start is treated as a key before all keys in the
+// DB. And a nil Range.Limit is treated as a key after all keys in
+// the DB.
+//
+// The iterator must be released after use, by calling Release method.
+//
+// Also read Iterator documentation of the leveldb/iterator package.
+func (db *DB) NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
+ if err := db.ok(); err != nil {
+ return iterator.NewEmptyIterator(err)
+ }
+
+ se := db.acquireSnapshot()
+ defer db.releaseSnapshot(se)
+ // Iterator holds 'version' lock, 'version' is immutable so snapshot
+ // can be released after iterator created.
+ return db.newIterator(nil, nil, se.seq, slice, ro)
+}
+
+// GetSnapshot returns a latest snapshot of the underlying DB. A snapshot
+// is a frozen snapshot of a DB state at a particular point in time. The
+// content of snapshot are guaranteed to be consistent.
+//
+// The snapshot must be released after use, by calling Release method.
+func (db *DB) GetSnapshot() (*Snapshot, error) {
+ if err := db.ok(); err != nil {
+ return nil, err
+ }
+
+ return db.newSnapshot(), nil
+}
+
+// GetProperty returns value of the given property name.
+//
+// Property names:
+// leveldb.num-files-at-level{n}
+// Returns the number of files at level 'n'.
+// leveldb.stats
+// Returns statistics of the underlying DB.
+// leveldb.writedelay
+// Returns cumulative write delay caused by compaction.
+// leveldb.sstables
+// Returns sstables list for each level.
+// leveldb.blockpool
+// Returns block pool stats.
+// leveldb.cachedblock
+// Returns size of cached block.
+// leveldb.openedtables
+// Returns number of opened tables.
+// leveldb.alivesnaps
+// Returns number of alive snapshots.
+// leveldb.aliveiters
+// Returns number of alive iterators.
+func (db *DB) GetProperty(name string) (value string, err error) {
+ err = db.ok()
+ if err != nil {
+ return
+ }
+
+ const prefix = "leveldb."
+ if !strings.HasPrefix(name, prefix) {
+ return "", ErrNotFound
+ }
+ p := name[len(prefix):]
+
+ v := db.s.version()
+ defer v.release()
+
+ numFilesPrefix := "num-files-at-level"
+ switch {
+ case strings.HasPrefix(p, numFilesPrefix):
+ var level uint
+ var rest string
+ n, _ := fmt.Sscanf(p[len(numFilesPrefix):], "%d%s", &level, &rest)
+ if n != 1 {
+ err = ErrNotFound
+ } else {
+ value = fmt.Sprint(v.tLen(int(level)))
+ }
+ case p == "stats":
+ value = "Compactions\n" +
+ " Level | Tables | Size(MB) | Time(sec) | Read(MB) | Write(MB)\n" +
+ "-------+------------+---------------+---------------+---------------+---------------\n"
+ for level, tables := range v.levels {
+ duration, read, write := db.compStats.getStat(level)
+ if len(tables) == 0 && duration == 0 {
+ continue
+ }
+ value += fmt.Sprintf(" %3d | %10d | %13.5f | %13.5f | %13.5f | %13.5f\n",
+ level, len(tables), float64(tables.size())/1048576.0, duration.Seconds(),
+ float64(read)/1048576.0, float64(write)/1048576.0)
+ }
+ case p == "writedelay":
+ writeDelayN, writeDelay := atomic.LoadInt32(&db.cWriteDelayN), time.Duration(atomic.LoadInt64(&db.cWriteDelay))
+ value = fmt.Sprintf("DelayN:%d Delay:%s", writeDelayN, writeDelay)
+ case p == "sstables":
+ for level, tables := range v.levels {
+ value += fmt.Sprintf("--- level %d ---\n", level)
+ for _, t := range tables {
+ value += fmt.Sprintf("%d:%d[%q .. %q]\n", t.fd.Num, t.size, t.imin, t.imax)
+ }
+ }
+ case p == "blockpool":
+ value = fmt.Sprintf("%v", db.s.tops.bpool)
+ case p == "cachedblock":
+ if db.s.tops.bcache != nil {
+ value = fmt.Sprintf("%d", db.s.tops.bcache.Size())
+ } else {
+ value = "<nil>"
+ }
+ case p == "openedtables":
+ value = fmt.Sprintf("%d", db.s.tops.cache.Size())
+ case p == "alivesnaps":
+ value = fmt.Sprintf("%d", atomic.LoadInt32(&db.aliveSnaps))
+ case p == "aliveiters":
+ value = fmt.Sprintf("%d", atomic.LoadInt32(&db.aliveIters))
+ default:
+ err = ErrNotFound
+ }
+
+ return
+}
+
+// SizeOf calculates approximate sizes of the given key ranges.
+// The length of the returned sizes are equal with the length of the given
+// ranges. The returned sizes measure storage space usage, so if the user
+// data compresses by a factor of ten, the returned sizes will be one-tenth
+// the size of the corresponding user data size.
+// The results may not include the sizes of recently written data.
+func (db *DB) SizeOf(ranges []util.Range) (Sizes, error) {
+ if err := db.ok(); err != nil {
+ return nil, err
+ }
+
+ v := db.s.version()
+ defer v.release()
+
+ sizes := make(Sizes, 0, len(ranges))
+ for _, r := range ranges {
+ imin := makeInternalKey(nil, r.Start, keyMaxSeq, keyTypeSeek)
+ imax := makeInternalKey(nil, r.Limit, keyMaxSeq, keyTypeSeek)
+ start, err := v.offsetOf(imin)
+ if err != nil {
+ return nil, err
+ }
+ limit, err := v.offsetOf(imax)
+ if err != nil {
+ return nil, err
+ }
+ var size int64
+ if limit >= start {
+ size = limit - start
+ }
+ sizes = append(sizes, size)
+ }
+
+ return sizes, nil
+}
+
+// Close closes the DB. This will also releases any outstanding snapshot,
+// abort any in-flight compaction and discard open transaction.
+//
+// It is not safe to close a DB until all outstanding iterators are released.
+// It is valid to call Close multiple times. Other methods should not be
+// called after the DB has been closed.
+func (db *DB) Close() error {
+ if !db.setClosed() {
+ return ErrClosed
+ }
+
+ start := time.Now()
+ db.log("db@close closing")
+
+ // Clear the finalizer.
+ runtime.SetFinalizer(db, nil)
+
+ // Get compaction error.
+ var err error
+ select {
+ case err = <-db.compErrC:
+ if err == ErrReadOnly {
+ err = nil
+ }
+ default:
+ }
+
+ // Signal all goroutines.
+ close(db.closeC)
+
+ // Discard open transaction.
+ if db.tr != nil {
+ db.tr.Discard()
+ }
+
+ // Acquire writer lock.
+ db.writeLockC <- struct{}{}
+
+ // Wait for all gorotines to exit.
+ db.closeW.Wait()
+
+ // Closes journal.
+ if db.journal != nil {
+ db.journal.Close()
+ db.journalWriter.Close()
+ db.journal = nil
+ db.journalWriter = nil
+ }
+
+ if db.writeDelayN > 0 {
+ db.logf("db@write was delayed N·%d T·%v", db.writeDelayN, db.writeDelay)
+ }
+
+ // Close session.
+ db.s.close()
+ db.logf("db@close done T·%v", time.Since(start))
+ db.s.release()
+
+ if db.closer != nil {
+ if err1 := db.closer.Close(); err == nil {
+ err = err1
+ }
+ db.closer = nil
+ }
+
+ // Clear memdbs.
+ db.clearMems()
+
+ return err
+}
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