Fantom-foundation/go-lachesis

package leveldb

import (
    "io/ioutil"
    "os"
    "path/filepath"
    "strings"

    "github.com/Fantom-foundation/go-lachesis/kvdb"
)

type producer struct {
    datadir string
}

// NewProducer of level db.
func NewProducer(datadir string) kvdb.DbProducer {
    return &producer{
        datadir: datadir,
    }
}

// Names of existing databases.
func (p *producer) Names() []string {
    var names []string

    files, err := ioutil.ReadDir(p.datadir)
    if err != nil {
        panic(err)
    }

    for _, f := range files {
        if !f.IsDir() {
            continue
        }
        dirname := f.Name()
        if strings.HasSuffix(dirname, "-ldb") {
            name := strings.TrimSuffix(dirname, "-ldb")
            names = append(names, name)
        }
    }
    return names
}

// OpenDb or create db with name.
func (p *producer) OpenDb(name string) kvdb.KeyValueStore {
    dir := name + "-ldb"
    path := filepath.Join(p.datadir, dir)

    err := os.MkdirAll(path, 0700)
    if err != nil {
        panic(err)
    }

    var stopWatcher func()
    onClose := func() error {
        if stopWatcher != nil {
            stopWatcher()
        }
        return nil
    }
    onDrop := func() {
        err := os.RemoveAll(path)
        if err != nil {
            panic(err)
        }

    }

    db, err := New(path, 16, 0, "", onClose, onDrop)
    if err != nil {
        panic(err)
    }

    // TODO: dir watcher instead of file watcher needed.
    //stopWatcher = metrics.StartFileWatcher(name+"_db_file_size", f)

    return db
}