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// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package shed provides a simple abstraction components to compose
// more complex operations on storage data organized in fields and indexes.
//
// Only type which holds logical information about swarm storage chunks data
// and metadata is IndexItem. This part is not generalized mostly for
// performance reasons.
package shed
import (
"github.com/ethereum/go-ethereum/metrics"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/opt"
)
// The limit for LevelDB OpenFilesCacheCapacity.
const openFileLimit = 128
// DB provides abstractions over LevelDB in order to
// implement complex structures using fields and ordered indexes.
// It provides a schema functionality to store fields and indexes
// information about naming and types.
type DB struct {
ldb *leveldb.DB
}
// NewDB constructs a new DB and validates the schema
// if it exists in database on the given path.
func NewDB(path string) (db *DB, err error) {
ldb, err := leveldb.OpenFile(path, &opt.Options{
OpenFilesCacheCapacity: openFileLimit,
})
if err != nil {
return nil, err
}
db = &DB{
ldb: ldb,
}
if _, err = db.getSchema(); err != nil {
if err == leveldb.ErrNotFound {
// save schema with initialized default fields
if err = db.putSchema(schema{
Fields: make(map[string]fieldSpec),
Indexes: make(map[byte]indexSpec),
}); err != nil {
return nil, err
}
} else {
return nil, err
}
}
return db, nil
}
// Put wraps LevelDB Put method to increment metrics counter.
func (db *DB) Put(key []byte, value []byte) (err error) {
err = db.ldb.Put(key, value, nil)
if err != nil {
metrics.GetOrRegisterCounter("DB.putFail", nil).Inc(1)
return err
}
metrics.GetOrRegisterCounter("DB.put", nil).Inc(1)
return nil
}
// Get wraps LevelDB Get method to increment metrics counter.
func (db *DB) Get(key []byte) (value []byte, err error) {
value, err = db.ldb.Get(key, nil)
if err != nil {
if err == leveldb.ErrNotFound {
metrics.GetOrRegisterCounter("DB.getNotFound", nil).Inc(1)
} else {
metrics.GetOrRegisterCounter("DB.getFail", nil).Inc(1)
}
return nil, err
}
metrics.GetOrRegisterCounter("DB.get", nil).Inc(1)
return value, nil
}
// Delete wraps LevelDB Delete method to increment metrics counter.
func (db *DB) Delete(key []byte) (err error) {
err = db.ldb.Delete(key, nil)
if err != nil {
metrics.GetOrRegisterCounter("DB.deleteFail", nil).Inc(1)
return err
}
metrics.GetOrRegisterCounter("DB.delete", nil).Inc(1)
return nil
}
// NewIterator wraps LevelDB NewIterator method to increment metrics counter.
func (db *DB) NewIterator() iterator.Iterator {
metrics.GetOrRegisterCounter("DB.newiterator", nil).Inc(1)
return db.ldb.NewIterator(nil, nil)
}
// WriteBatch wraps LevelDB Write method to increment metrics counter.
func (db *DB) WriteBatch(batch *leveldb.Batch) (err error) {
err = db.ldb.Write(batch, nil)
if err != nil {
metrics.GetOrRegisterCounter("DB.writebatchFail", nil).Inc(1)
return err
}
metrics.GetOrRegisterCounter("DB.writebatch", nil).Inc(1)
return nil
}
// Close closes LevelDB database.
func (db *DB) Close() (err error) {
return db.ldb.Close()
}
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