/
batch.go
51 lines (41 loc) · 1.34 KB
/
batch.go
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package leveldb
// Batch is a write-only database that commits changes to its host database
// when Write is called. A batch cannot be used concurrently.
type Batch interface {
KeyValueWriter
// ValueSize retrieves the amount of data queued up for writing.
ValueSize() int
// Write flushes any accumulated data to disk.
Write() error
// Reset resets the batch for reuse.
Reset()
// Replay replays the batch contents.
Replay(w KeyValueWriter) error
}
// Batcher wraps the NewBatch method of a backing data store.
type Batcher interface {
// NewBatch creates a write-only database that buffers changes to its host db
// until a final write is called.
NewBatch() Batch
}
// HookedBatch wraps an arbitrary batch where each operation may be hooked into
// to monitor from black box code.
type HookedBatch struct {
Batch
OnPut func(key []byte, value []byte) // Callback if a key is inserted
OnDelete func(key []byte) // Callback if a key is deleted
}
// Put inserts the given value into the key-value data store.
func (b HookedBatch) Put(key []byte, value []byte) error {
if b.OnPut != nil {
b.OnPut(key, value)
}
return b.Batch.Put(key, value)
}
// Delete removes the key from the key-value data store.
func (b HookedBatch) Delete(key []byte) error {
if b.OnDelete != nil {
b.OnDelete(key)
}
return b.Batch.Delete(key)
}