github.com/theQRL/go-zond@v0.1.1/zonddb/snapshot.go (about)

     1  // Copyright 2022 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 zonddb
    18  
    19  type Snapshot interface {
    20  	// Has retrieves if a key is present in the snapshot backing by a key-value
    21  	// data store.
    22  	Has(key []byte) (bool, error)
    23  
    24  	// Get retrieves the given key if it's present in the snapshot backing by
    25  	// key-value data store.
    26  	Get(key []byte) ([]byte, error)
    27  
    28  	// Release releases associated resources. Release should always succeed and can
    29  	// be called multiple times without causing error.
    30  	Release()
    31  }
    32  
    33  // Snapshotter wraps the Snapshot method of a backing data store.
    34  type Snapshotter interface {
    35  	// NewSnapshot creates a database snapshot based on the current state.
    36  	// The created snapshot will not be affected by all following mutations
    37  	// happened on the database.
    38  	// Note don't forget to release the snapshot once it's used up, otherwise
    39  	// the stale data will never be cleaned up by the underlying compactor.
    40  	NewSnapshot() (Snapshot, error)
    41  }