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

     1  // Copyright 2018 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  // IdealBatchSize defines the size of the data batches should ideally add in one
    20  // write.
    21  const IdealBatchSize = 100 * 1024
    22  
    23  // Batch is a write-only database that commits changes to its host database
    24  // when Write is called. A batch cannot be used concurrently.
    25  type Batch interface {
    26  	KeyValueWriter
    27  
    28  	// ValueSize retrieves the amount of data queued up for writing.
    29  	ValueSize() int
    30  
    31  	// Write flushes any accumulated data to disk.
    32  	Write() error
    33  
    34  	// Reset resets the batch for reuse.
    35  	Reset()
    36  
    37  	// Replay replays the batch contents.
    38  	Replay(w KeyValueWriter) error
    39  }
    40  
    41  // Batcher wraps the NewBatch method of a backing data store.
    42  type Batcher interface {
    43  	// NewBatch creates a write-only database that buffers changes to its host db
    44  	// until a final write is called.
    45  	NewBatch() Batch
    46  
    47  	// NewBatchWithSize creates a write-only database batch with pre-allocated buffer.
    48  	NewBatchWithSize(size int) Batch
    49  }
    50  
    51  // HookedBatch wraps an arbitrary batch where each operation may be hooked into
    52  // to monitor from black box code.
    53  type HookedBatch struct {
    54  	Batch
    55  
    56  	OnPut    func(key []byte, value []byte) // Callback if a key is inserted
    57  	OnDelete func(key []byte)               // Callback if a key is deleted
    58  }
    59  
    60  // Put inserts the given value into the key-value data store.
    61  func (b HookedBatch) Put(key []byte, value []byte) error {
    62  	if b.OnPut != nil {
    63  		b.OnPut(key, value)
    64  	}
    65  	return b.Batch.Put(key, value)
    66  }
    67  
    68  // Delete removes the key from the key-value data store.
    69  func (b HookedBatch) Delete(key []byte) error {
    70  	if b.OnDelete != nil {
    71  		b.OnDelete(key)
    72  	}
    73  	return b.Batch.Delete(key)
    74  }