// writeBatch applies the puts, merges and deletes atomically via
// the RocksDB write batch facility. The list must only contain
// elements of type Batch{Put,Merge,Delete}.
func (r *RocksDB) writeBatch(cmds []interface{}) error {
if len(cmds) == 0 {
return nil
}
batch := C.rocksdb_writebatch_create()
defer C.rocksdb_writebatch_destroy(batch)
for i, e := range cmds {
switch v := e.(type) {
case BatchDelete:
if len(v) == 0 {
return emptyKeyError()
}
C.rocksdb_writebatch_delete(
batch,
(*C.char)(unsafe.Pointer(&v[0])),
C.size_t(len(v)))
case BatchPut:
key, value := v.Key, v.Value
valuePointer := (*C.char)(nil)
if len(value.Bytes) > 0 {
valuePointer = (*C.char)(unsafe.Pointer(&value.Bytes[0]))
}
// We write the batch before returning from this method, so we
// don't need to worry about the GC reclaiming the data stored.
C.rocksdb_writebatch_put(
batch,
(*C.char)(unsafe.Pointer(&key[0])),
C.size_t(len(key)),
valuePointer,
C.size_t(len(value.Bytes)))
case BatchMerge:
key, value := v.Key, v.Value
valuePointer := (*C.char)(nil)
if len(value.Bytes) > 0 {
valuePointer = (*C.char)(unsafe.Pointer(&value.Bytes[0]))
}
C.rocksdb_writebatch_merge(
batch,
(*C.char)(unsafe.Pointer(&key[0])),
C.size_t(len(key)),
valuePointer,
C.size_t(len(value.Bytes)))
default:
panic(fmt.Sprintf("illegal operation #%d passed to writeBatch: %v", i, reflect.TypeOf(v)))
}
}
var cErr *C.char
C.rocksdb_write(r.rdb, r.wOpts, batch, &cErr)
if cErr != nil {
return charToErr(cErr)
}
return nil
}
// Merge queues a merge of "value" with the existing value of "key".
func (w *WriteBatch) Merge(key, value []byte) {
cKey := byteToChar(key)
cValue := byteToChar(value)
C.rocksdb_writebatch_merge(w.c, cKey, C.size_t(len(key)), cValue, C.size_t(len(value)))
}