path: root/ethdb/database.go

package ethdb

import (
    "sync"

    "github.com/ethereum/go-ethereum/compression/rle"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/syndtr/goleveldb/leveldb"
    "github.com/syndtr/goleveldb/leveldb/iterator"
    "github.com/syndtr/goleveldb/leveldb/opt"
)

var OpenFileLimit = 64

type LDBDatabase struct {
    fn string

    mu sync.Mutex
    db *leveldb.DB

    queue map[string][]byte

    quit chan struct{}
}

func NewLDBDatabase(file string) (*LDBDatabase, error) {
    // Open the db
    db, err := leveldb.OpenFile(file, &opt.Options{OpenFilesCacheCapacity: OpenFileLimit})
    if err != nil {
        return nil, err
    }
    database := &LDBDatabase{
        fn:   file,
        db:   db,
        quit: make(chan struct{}),
    }
    database.makeQueue()

    return database, nil
}

func (self *LDBDatabase) makeQueue() {
    self.queue = make(map[string][]byte)
}

func (self *LDBDatabase) Put(key []byte, value []byte) {
    self.mu.Lock()
    defer self.mu.Unlock()

    self.queue[string(key)] = value
    /*
        value = rle.Compress(value)

        err := self.db.Put(key, value, nil)
        if err != nil {
            fmt.Println("Error put", err)
        }
    */
}

func (self *LDBDatabase) Get(key []byte) ([]byte, error) {
    self.mu.Lock()
    defer self.mu.Unlock()

    // Check queue first
    if dat, ok := self.queue[string(key)]; ok {
        return dat, nil
    }

    dat, err := self.db.Get(key, nil)
    if err != nil {
        return nil, err
    }

    return rle.Decompress(dat)
}

func (self *LDBDatabase) Delete(key []byte) error {
    self.mu.Lock()
    defer self.mu.Unlock()

    // make sure it's not in the queue
    delete(self.queue, string(key))

    return self.db.Delete(key, nil)
}

func (self *LDBDatabase) LastKnownTD() []byte {
    data, _ := self.Get([]byte("LTD"))

    if len(data) == 0 {
        data = []byte{0x0}
    }

    return data
}

func (self *LDBDatabase) NewIterator() iterator.Iterator {
    return self.db.NewIterator(nil, nil)
}

func (self *LDBDatabase) Flush() error {
    self.mu.Lock()
    defer self.mu.Unlock()

    batch := new(leveldb.Batch)

    for key, value := range self.queue {
        batch.Put([]byte(key), rle.Compress(value))
    }
    self.makeQueue() // reset the queue

    glog.V(logger.Detail).Infoln("Flush database: ", self.fn)

    return self.db.Write(batch, 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)
}