github.com/nitinawathare/ethereumassignment3@v0.0.0-20211021213010-f07344c2b868/go-ethereum/swarm/storage/localstore/mode_has.go (about)

     1  // Copyright 2019 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package localstore
    18  
    19  import (
    20  	"github.com/ethereum/go-ethereum/swarm/chunk"
    21  )
    22  
    23  // Hasser provides Has method to retrieve Chunks
    24  // from database.
    25  type Hasser struct {
    26  	db *DB
    27  }
    28  
    29  // NewHasser returns a new Hasser on database.
    30  func (db *DB) NewHasser() *Hasser {
    31  	return &Hasser{
    32  		db: db,
    33  	}
    34  }
    35  
    36  // Has returns true if the chunk is stored in database.
    37  func (h *Hasser) Has(addr chunk.Address) (bool, error) {
    38  	return h.db.retrievalDataIndex.Has(addressToItem(addr))
    39  }