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package ethdb
import (
"time"
"github.com/ethereum/go-ethereum/compression/rle"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/rcrowley/go-metrics"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/errors"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/opt"
)
var OpenFileLimit = 64
type LDBDatabase struct {
fn string // filename for reporting
db *leveldb.DB // LevelDB instance
GetTimer metrics.Timer // Timer for measuring the database get request counts and latencies
PutTimer metrics.Timer // Timer for measuring the database put request counts and latencies
DelTimer metrics.Timer // Timer for measuring the database delete request counts and latencies
MissMeter metrics.Meter // MEter for measuring the missed database get requests
ReadMeter metrics.Meter // Meter for measuring the database get request data usage
WriteMeter metrics.Meter // Meter for measuring the database put request data usage
}
// NewLDBDatabase returns a LevelDB wrapped object. LDBDatabase does not persist data by
// it self but requires a background poller which syncs every X. `Flush` should be called
// when data needs to be stored and written to disk.
func NewLDBDatabase(file string) (*LDBDatabase, error) {
// Open the db
db, err := leveldb.OpenFile(file, &opt.Options{OpenFilesCacheCapacity: OpenFileLimit})
// check for curruption and attempt to recover
if _, iscorrupted := err.(*errors.ErrCorrupted); iscorrupted {
db, err = leveldb.RecoverFile(file, nil)
}
// (re) check for errors and abort if opening of the db failed
if err != nil {
return nil, err
}
database := &LDBDatabase{
fn: file,
db: db,
}
return database, nil
}
// Put puts the given key / value to the queue
func (self *LDBDatabase) Put(key []byte, value []byte) error {
// Measure the database put latency, if requested
if self.PutTimer != nil {
start := time.Now()
defer self.PutTimer.UpdateSince(start)
}
// Generate the data to write to disk, update the meter and write
dat := rle.Compress(value)
if self.WriteMeter != nil {
self.WriteMeter.Mark(int64(len(dat)))
}
return self.db.Put(key, dat, nil)
}
// Get returns the given key if it's present.
func (self *LDBDatabase) Get(key []byte) ([]byte, error) {
// Measure the database get latency, if requested
if self.GetTimer != nil {
start := time.Now()
defer self.GetTimer.UpdateSince(start)
}
// Retrieve the key and increment the miss counter if not found
dat, err := self.db.Get(key, nil)
if err != nil {
if self.MissMeter != nil {
self.MissMeter.Mark(1)
}
return nil, err
}
// Otherwise update the actually retrieved amount of data
if self.ReadMeter != nil {
self.ReadMeter.Mark(int64(len(dat)))
}
return rle.Decompress(dat)
}
// Delete deletes the key from the queue and database
func (self *LDBDatabase) Delete(key []byte) error {
// Measure the database delete latency, if requested
if self.DelTimer != nil {
start := time.Now()
defer self.DelTimer.UpdateSince(start)
}
// Execute the actual operation
return self.db.Delete(key, nil)
}
func (self *LDBDatabase) NewIterator() iterator.Iterator {
return self.db.NewIterator(nil, nil)
}
// Flush flushes out the queue to leveldb
func (self *LDBDatabase) Flush() error {
return nil
}
func (self *LDBDatabase) Close() {
if err := self.Flush(); err != nil {
glog.V(logger.Error).Infof("error: flush '%s': %v\n", self.fn, err)
}
self.db.Close()
glog.V(logger.Error).Infoln("flushed and closed db:", self.fn)
}
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