diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/session.go')
-rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/session.go | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/session.go b/vendor/github.com/syndtr/goleveldb/leveldb/session.go new file mode 100644 index 000000000..f3e747701 --- /dev/null +++ b/vendor/github.com/syndtr/goleveldb/leveldb/session.go @@ -0,0 +1,208 @@ +// 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 ( + "fmt" + "io" + "os" + "sync" + + "github.com/syndtr/goleveldb/leveldb/errors" + "github.com/syndtr/goleveldb/leveldb/journal" + "github.com/syndtr/goleveldb/leveldb/opt" + "github.com/syndtr/goleveldb/leveldb/storage" +) + +// ErrManifestCorrupted records manifest corruption. This error will be +// wrapped with errors.ErrCorrupted. +type ErrManifestCorrupted struct { + Field string + Reason string +} + +func (e *ErrManifestCorrupted) Error() string { + return fmt.Sprintf("leveldb: manifest corrupted (field '%s'): %s", e.Field, e.Reason) +} + +func newErrManifestCorrupted(fd storage.FileDesc, field, reason string) error { + return errors.NewErrCorrupted(fd, &ErrManifestCorrupted{field, reason}) +} + +// session represent a persistent database session. +type session struct { + // Need 64-bit alignment. + stNextFileNum int64 // current unused file number + stJournalNum int64 // current journal file number; need external synchronization + stPrevJournalNum int64 // prev journal file number; no longer used; for compatibility with older version of leveldb + stTempFileNum int64 + stSeqNum uint64 // last mem compacted seq; need external synchronization + + stor storage.Storage + storLock storage.Locker + o *cachedOptions + icmp *iComparer + tops *tOps + + manifest *journal.Writer + manifestWriter storage.Writer + manifestFd storage.FileDesc + + stCompPtrs []internalKey // compaction pointers; need external synchronization + stVersion *version // current version + vmu sync.Mutex +} + +// Creates new initialized session instance. +func newSession(stor storage.Storage, o *opt.Options) (s *session, err error) { + if stor == nil { + return nil, os.ErrInvalid + } + storLock, err := stor.Lock() + if err != nil { + return + } + s = &session{ + stor: stor, + storLock: storLock, + } + s.setOptions(o) + s.tops = newTableOps(s) + s.setVersion(newVersion(s)) + s.log("log@legend F·NumFile S·FileSize N·Entry C·BadEntry B·BadBlock Ke·KeyError D·DroppedEntry L·Level Q·SeqNum T·TimeElapsed") + return +} + +// Close session. +func (s *session) close() { + s.tops.close() + if s.manifest != nil { + s.manifest.Close() + } + if s.manifestWriter != nil { + s.manifestWriter.Close() + } + s.manifest = nil + s.manifestWriter = nil + s.setVersion(&version{s: s, closing: true}) +} + +// Release session lock. +func (s *session) release() { + s.storLock.Unlock() +} + +// Create a new database session; need external synchronization. +func (s *session) create() error { + // create manifest + return s.newManifest(nil, nil) +} + +// Recover a database session; need external synchronization. +func (s *session) recover() (err error) { + defer func() { + if os.IsNotExist(err) { + // Don't return os.ErrNotExist if the underlying storage contains + // other files that belong to LevelDB. So the DB won't get trashed. + if fds, _ := s.stor.List(storage.TypeAll); len(fds) > 0 { + err = &errors.ErrCorrupted{Fd: storage.FileDesc{Type: storage.TypeManifest}, Err: &errors.ErrMissingFiles{}} + } + } + }() + + fd, err := s.stor.GetMeta() + if err != nil { + return + } + + reader, err := s.stor.Open(fd) + if err != nil { + return + } + defer reader.Close() + + var ( + // Options. + strict = s.o.GetStrict(opt.StrictManifest) + + jr = journal.NewReader(reader, dropper{s, fd}, strict, true) + rec = &sessionRecord{} + staging = s.stVersion.newStaging() + ) + for { + var r io.Reader + r, err = jr.Next() + if err != nil { + if err == io.EOF { + err = nil + break + } + return errors.SetFd(err, fd) + } + + err = rec.decode(r) + if err == nil { + // save compact pointers + for _, r := range rec.compPtrs { + s.setCompPtr(r.level, internalKey(r.ikey)) + } + // commit record to version staging + staging.commit(rec) + } else { + err = errors.SetFd(err, fd) + if strict || !errors.IsCorrupted(err) { + return + } + s.logf("manifest error: %v (skipped)", errors.SetFd(err, fd)) + } + rec.resetCompPtrs() + rec.resetAddedTables() + rec.resetDeletedTables() + } + + switch { + case !rec.has(recComparer): + return newErrManifestCorrupted(fd, "comparer", "missing") + case rec.comparer != s.icmp.uName(): + return newErrManifestCorrupted(fd, "comparer", fmt.Sprintf("mismatch: want '%s', got '%s'", s.icmp.uName(), rec.comparer)) + case !rec.has(recNextFileNum): + return newErrManifestCorrupted(fd, "next-file-num", "missing") + case !rec.has(recJournalNum): + return newErrManifestCorrupted(fd, "journal-file-num", "missing") + case !rec.has(recSeqNum): + return newErrManifestCorrupted(fd, "seq-num", "missing") + } + + s.manifestFd = fd + s.setVersion(staging.finish()) + s.setNextFileNum(rec.nextFileNum) + s.recordCommited(rec) + return nil +} + +// Commit session; need external synchronization. +func (s *session) commit(r *sessionRecord) (err error) { + v := s.version() + defer v.release() + + // spawn new version based on current version + nv := v.spawn(r) + + if s.manifest == nil { + // manifest journal writer not yet created, create one + err = s.newManifest(r, nv) + } else { + err = s.flushManifest(r) + } + + // finally, apply new version if no error rise + if err == nil { + s.setVersion(nv) + } + + return +} |