mtsatellite/cmd/mtredisalize/leveldb.go

374 lines
8.0 KiB
Go
Raw Normal View History

2014-08-03 15:59:56 +02:00
// Copyright 2014 by Sascha L. Teichmann
// Use of this source code is governed by the MIT license
// that can be found in the LICENSE file.
package main
import (
"log"
"sync"
"bitbucket.org/s_l_teichmann/mtredisalize/common"
leveldb "github.com/jmhodges/levigo"
)
type LevelDBBackend struct {
cache *leveldb.Cache
db *leveldb.DB
interleaved bool
encoder common.KeyTranscoder
decoder common.KeyTranscoder
mutex sync.RWMutex
}
type LevelDBSession struct {
backend *LevelDBBackend
tx *leveldb.WriteBatch
}
func NewLeveDBBackend(
path string,
interleaved bool,
cacheSize int) (ldb *LevelDBBackend, err error) {
opts := leveldb.NewOptions()
var cache *leveldb.Cache
if cacheSize > 0 {
cache = leveldb.NewLRUCache(cacheSize * 1024 * 1024)
opts.SetCache(cache)
}
opts.SetCreateIfMissing(true)
var db *leveldb.DB
if db, err = leveldb.Open(path, opts); err != nil {
if cache != nil {
cache.Close()
}
return
}
var (
encoder common.KeyTranscoder
decoder common.KeyTranscoder
)
if interleaved {
encoder = common.TranscodeInterleavedToPlain
decoder = common.TranscodePlainToInterleaved
} else {
encoder = common.IdentityTranscoder
decoder = common.IdentityTranscoder
}
ldb = &LevelDBBackend{
cache: cache,
db: db,
interleaved: interleaved,
encoder: encoder,
decoder: decoder}
return
}
func (ldb *LevelDBBackend) doRead(f func(db *leveldb.DB)) {
ldb.mutex.RLock()
f(ldb.db)
ldb.mutex.RUnlock()
}
func (ldb *LevelDBBackend) doWrite(f func(db *leveldb.DB)) {
ldb.mutex.Lock()
f(ldb.db)
ldb.mutex.Unlock()
}
func (ldb *LevelDBBackend) NewSession() (Session, error) {
return &LevelDBSession{ldb, nil}, nil
}
func (ldbs *LevelDBSession) Close() error {
if ldbs.tx != nil {
ldbs.tx.Close()
2014-08-04 15:29:26 +02:00
}
return nil
}
func (ldb *LevelDBBackend) Shutdown() error {
ldb.db.Close()
if ldb.cache != nil {
ldb.cache.Close()
}
return nil
}
func (ldbs *LevelDBSession) Fetch(hash, key []byte) (value []byte, err error) {
if key, err = ldbs.backend.decoder(key); err != nil {
return
}
ldbs.backend.doRead(func(db *leveldb.DB) {
ro := leveldb.NewReadOptions()
value, err = ldbs.backend.db.Get(ro, key)
2014-08-08 00:16:00 +02:00
//if err != nil {
// log.Printf("Fetch key '%s' failed.\n", key)
//} else {
// log.Printf("Fetch key = '%s' len(value) = %d\n", key, len(value))
//}
ro.Close()
})
2014-08-04 22:23:16 +02:00
return
}
func (ldbs *LevelDBSession) InTransaction() bool {
return ldbs.tx != nil
}
func keyExists(db *leveldb.DB, key []byte) (exists bool, err error) {
ro := leveldb.NewReadOptions()
defer ro.Close()
var data []byte
if data, err = db.Get(ro, key); err != nil {
return
}
exists = data != nil
return
}
func (ldbs *LevelDBSession) Store(hash, key, value []byte) (exists bool, err error) {
if key, err = ldbs.backend.decoder(key); err != nil {
return
}
ldbs.backend.doWrite(func(db *leveldb.DB) {
if exists, err = keyExists(db, key); err != nil {
return
}
if ldbs.tx != nil {
ldbs.tx.Put(key, value)
return
}
wo := leveldb.NewWriteOptions()
err = ldbs.backend.db.Put(wo, key, value)
wo.Close()
})
return
}
func (ldbs *LevelDBSession) BeginTransaction() error {
ldbs.tx = leveldb.NewWriteBatch()
return nil
}
func (ldbs *LevelDBSession) CommitTransaction() (err error) {
tx := ldbs.tx
if tx == nil {
log.Println("WARN: No transaction running.")
return
}
ldbs.tx = nil
ldbs.backend.doWrite(func(db *leveldb.DB) {
wo := leveldb.NewWriteOptions()
wo.SetSync(true)
err = db.Write(wo, tx)
wo.Close()
tx.Close()
})
2014-08-04 15:29:26 +02:00
return
}
func (ldbs *LevelDBSession) AllKeys(hash []byte, done chan struct{}) (keys chan []byte, n int, err error) {
ldbs.backend.mutex.RLock()
ro := leveldb.NewReadOptions()
ro.SetFillCache(false)
it := ldbs.backend.db.NewIterator(ro)
it.SeekToFirst()
for ; it.Valid(); it.Next() {
n++
}
if err = it.GetError(); err != nil {
it.Close()
ro.Close()
ldbs.backend.mutex.RUnlock()
return
}
keys = make(chan []byte)
go func() {
ldbs.backend.mutex.RUnlock()
defer ro.Close()
defer close(keys)
defer it.Close()
it.SeekToFirst()
encoder := ldbs.backend.encoder
for ; it.Valid(); it.Next() {
if key, err := encoder(it.Key()); err == nil {
select {
case keys <- key:
case <-done:
return
}
} else {
log.Printf("WARN: %s\n", err)
return
}
}
if err := it.GetError(); err != nil {
log.Printf("WARN: %s\n", err)
}
}()
return
}
func (ldbs *LevelDBSession) SpatialQuery(hash, first, second []byte, done chan struct{}) (chan Block, error) {
if ldbs.backend.interleaved {
return ldbs.interleavedSpatialQuery(first, second, done)
}
return ldbs.plainSpatialQuery(first, second, done)
}
func (ldbs *LevelDBSession) plainSpatialQuery(first, second []byte, done chan struct{}) (blocks chan Block, err error) {
var (
firstKey int64
secondKey int64
)
if firstKey, err = common.DecodeStringFromBytes(first); err != nil {
return
}
if secondKey, err = common.DecodeStringFromBytes(second); err != nil {
return
}
c1 := common.PlainToCoord(firstKey)
c2 := common.PlainToCoord(secondKey)
c1, c2 = common.MinCoord(c1, c2), common.MaxCoord(c1, c2)
blocks = make(chan Block)
go func() {
defer close(blocks)
ldbs.backend.mutex.RLock()
defer ldbs.backend.mutex.RUnlock()
ro := leveldb.NewReadOptions()
defer ro.Close()
ro.SetFillCache(false)
it := ldbs.backend.db.NewIterator(ro)
defer it.Close()
a, b := common.Coord{X: c1.X}, common.Coord{X: c2.X}
var err error
for a.Z = c1.Z; a.Z <= c2.Z; a.Z++ {
b.Z = a.Z
for a.Y = c1.Y; a.Y <= c2.Y; a.Y++ {
b.Y = a.Y
from, to := order(common.CoordToPlain(a), common.CoordToPlain(b))
it.Seek(common.StringToBytes(from))
for ; it.Valid(); it.Next() {
var (
key = it.Key()
pos int64
)
if pos, err = common.DecodeStringFromBytes(key); err != nil {
log.Printf("decoding key failed: %s", err)
return
}
if pos > to {
break
}
select {
case blocks <- Block{Key: key, Data: it.Value()}:
case <-done:
return
}
}
if err = it.GetError(); err != nil {
log.Printf("iterating failed: %s", err)
return
}
}
}
}()
return
}
func (ldbs *LevelDBSession) interleavedSpatialQuery(first, second []byte, done chan struct{}) (blocks chan Block, err error) {
var (
firstKey int64
secondKey int64
)
if firstKey, err = common.DecodeStringFromBytes(first); err != nil {
return
}
if secondKey, err = common.DecodeStringFromBytes(second); err != nil {
return
}
c1 := common.ClipCoord(common.PlainToCoord(firstKey))
c2 := common.ClipCoord(common.PlainToCoord(secondKey))
c1, c2 = common.MinCoord(c1, c2), common.MaxCoord(c1, c2)
blocks = make(chan Block)
go func() {
defer close(blocks)
ldbs.backend.mutex.RLock()
defer ldbs.backend.mutex.RUnlock()
ro := leveldb.NewReadOptions()
defer ro.Close()
ro.SetFillCache(false)
it := ldbs.backend.db.NewIterator(ro)
defer it.Close()
zmin, zmax := common.CoordToInterleaved(c1), common.CoordToInterleaved(c2)
// Should not be necessary.
zmin, zmax = order(zmin, zmax)
var (
cub = common.Cuboid{P1: c1, P2: c2}
err error
encodedKey []byte
)
//log.Printf("seeking to: %d", zmin)
it.Seek(common.ToBigEndian(zmin))
for it.Valid() {
zcode := common.FromBigEndian(it.Key())
if zcode > zmax {
break
}
if c := common.InterleavedToCoord(zcode); cub.Contains(c) {
if encodedKey, err = common.EncodeStringToBytes(common.CoordToPlain(c)); err != nil {
log.Printf("error encoding key: %s", err)
return
}
select {
case blocks <- Block{Key: encodedKey, Data: it.Value()}:
case <-done:
return
}
it.Next()
} else {
next := common.BigMin(zmin, zmax, zcode)
//log.Printf("seeking to: %d", next)
it.Seek(common.ToBigEndian(next))
//log.Printf("seeking done: %d", next)
}
}
//log.Println("iterating done")
if err = it.GetError(); err != nil {
log.Printf("error while iterating: %s", err)
return
}
}()
return
}