72 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
		
		
			
		
	
	
			72 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
|   | // 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 | ||
|  | 
 | ||
|  | import ( | ||
|  | 	"github.com/ethereum/go-ethereum/rlp" | ||
|  | 	"github.com/syndtr/goleveldb/leveldb" | ||
|  | ) | ||
|  | 
 | ||
|  | // StructField is a helper to store complex structure by | ||
|  | // encoding it in RLP format. | ||
|  | type StructField struct { | ||
|  | 	db  *DB | ||
|  | 	key []byte | ||
|  | } | ||
|  | 
 | ||
|  | // NewStructField returns a new StructField. | ||
|  | // It validates its name and type against the database schema. | ||
|  | func (db *DB) NewStructField(name string) (f StructField, err error) { | ||
|  | 	key, err := db.schemaFieldKey(name, "struct-rlp") | ||
|  | 	if err != nil { | ||
|  | 		return f, err | ||
|  | 	} | ||
|  | 	return StructField{ | ||
|  | 		db:  db, | ||
|  | 		key: key, | ||
|  | 	}, nil | ||
|  | } | ||
|  | 
 | ||
|  | // Get unmarshals data from the database to a provided val. | ||
|  | // If the data is not found leveldb.ErrNotFound is returned. | ||
|  | func (f StructField) Get(val interface{}) (err error) { | ||
|  | 	b, err := f.db.Get(f.key) | ||
|  | 	if err != nil { | ||
|  | 		return err | ||
|  | 	} | ||
|  | 	return rlp.DecodeBytes(b, val) | ||
|  | } | ||
|  | 
 | ||
|  | // Put marshals provided val and saves it to the database. | ||
|  | func (f StructField) Put(val interface{}) (err error) { | ||
|  | 	b, err := rlp.EncodeToBytes(val) | ||
|  | 	if err != nil { | ||
|  | 		return err | ||
|  | 	} | ||
|  | 	return f.db.Put(f.key, b) | ||
|  | } | ||
|  | 
 | ||
|  | // PutInBatch marshals provided val and puts it into the batch. | ||
|  | func (f StructField) PutInBatch(batch *leveldb.Batch, val interface{}) (err error) { | ||
|  | 	b, err := rlp.EncodeToBytes(val) | ||
|  | 	if err != nil { | ||
|  | 		return err | ||
|  | 	} | ||
|  | 	batch.Put(f.key, b) | ||
|  | 	return nil | ||
|  | } |