github.com/ethereum/go-ethereum@v1.16.1/ethdb/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 ethdb
    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  	KeyValueRangeDeleter
    28  
    29  	// ValueSize retrieves the amount of data queued up for writing.
    30  	ValueSize() int
    31  
    32  	// Write flushes any accumulated data to disk.
    33  	Write() error
    34  
    35  	// Reset resets the batch for reuse.
    36  	Reset()
    37  
    38  	// Replay replays the batch contents.
    39  	Replay(w KeyValueWriter) error
    40  }
    41  
    42  // Batcher wraps the NewBatch method of a backing data store.
    43  type Batcher interface {
    44  	// NewBatch creates a write-only database that buffers changes to its host db
    45  	// until a final write is called.
    46  	NewBatch() Batch
    47  
    48  	// NewBatchWithSize creates a write-only database batch with pre-allocated buffer.
    49  	NewBatchWithSize(size int) Batch
    50  }
    51  
    52  // HookedBatch wraps an arbitrary batch where each operation may be hooked into
    53  // to monitor from black box code.
    54  type HookedBatch struct {
    55  	Batch
    56  
    57  	OnPut         func(key []byte, value []byte) // Callback if a key is inserted
    58  	OnDelete      func(key []byte)               // Callback if a key is deleted
    59  	OnDeleteRange func(start, end []byte)        // Callback if a range of keys is deleted
    60  }
    61  
    62  // Put inserts the given value into the key-value data store.
    63  func (b HookedBatch) Put(key []byte, value []byte) error {
    64  	if b.OnPut != nil {
    65  		b.OnPut(key, value)
    66  	}
    67  	return b.Batch.Put(key, value)
    68  }
    69  
    70  // Delete removes the key from the key-value data store.
    71  func (b HookedBatch) Delete(key []byte) error {
    72  	if b.OnDelete != nil {
    73  		b.OnDelete(key)
    74  	}
    75  	return b.Batch.Delete(key)
    76  }
    77  
    78  // DeleteRange removes all keys in the range [start, end) from the key-value data store.
    79  func (b HookedBatch) DeleteRange(start, end []byte) error {
    80  	if b.OnDeleteRange != nil {
    81  		b.OnDeleteRange(start, end)
    82  	}
    83  	return b.Batch.DeleteRange(start, end)
    84  }