Golang proto.Value類代碼示例

// mustGetInteger decodes an int64 value from the bytes field of the receiver
// and panics if the bytes field is not 0 or 8 bytes in length.
func mustGetInteger(v *proto.Value) int64 {
	i, err := v.GetInteger()
	if err != nil {
		panic(err)
	}
	return i
}

// ConditionalPut sets the value for a specified key only if
// the expected value matches. If not, the return value contains
// the actual value.
func (mvcc *MVCC) ConditionalPut(key Key, timestamp proto.Timestamp, value proto.Value, expValue *proto.Value, txn *proto.Transaction) (*proto.Value, error) {
	// Handle check for non-existence of key. In order to detect
	// the potential write intent by another concurrent transaction
	// with a newer timestamp, we need to use the max timestamp
	// while reading.
	existVal, err := mvcc.Get(key, proto.MaxTimestamp, txn)
	if err != nil {
		return nil, err
	}

	if expValue == nil && existVal != nil {
		return existVal, util.Errorf("key %q already exists", key)
	} else if expValue != nil {
		// Handle check for existence when there is no key.
		if existVal == nil {
			return nil, util.Errorf("key %q does not exist", key)
		} else if expValue.Bytes != nil && !bytes.Equal(expValue.Bytes, existVal.Bytes) {
			return existVal, util.Errorf("key %q does not match existing", key)
		} else if expValue.Integer != nil && (existVal.Integer == nil || expValue.GetInteger() != existVal.GetInteger()) {
			return existVal, util.Errorf("key %q does not match existing", key)
		}
	}

	return nil, mvcc.Put(key, timestamp, value, txn)
}

// putInternal writes the specified value to key.
func (kv *KV) putInternal(key proto.Key, value proto.Value) error {
	value.InitChecksum(key)
	return kv.Call(proto.Put, &proto.PutRequest{
		RequestHeader: proto.RequestHeader{Key: key},
		Value:         value,
	}, &proto.PutResponse{})
}

// PutProto sets the given key to the protobuf-serialized byte string
// of msg and the provided timestamp.
func (mvcc *MVCC) PutProto(key Key, timestamp proto.Timestamp, txn *proto.Transaction, msg gogoproto.Message) error {
	data, err := gogoproto.Marshal(msg)
	if err != nil {
		return err
	}
	value := proto.Value{Bytes: data}
	value.InitChecksum(key)
	return mvcc.Put(key, timestamp, value, txn)
}

// mustGetInt decodes an int64 value from the bytes field of the receiver
// and panics if the bytes field is not 0 or 8 bytes in length.
func mustGetInt(v *proto.Value) int64 {
	if v == nil {
		return 0
	}
	i, err := v.GetInt()
	if err != nil {
		panic(err)
	}
	return i
}

// Indirectly this tests that the transaction remembers the NodeID of the node
// being read from correctly, at least in this simple case. Not remembering the
// node would lead to thousands of transaction restarts and almost certainly a
// test timeout.
func TestUncertaintyRestarts(t *testing.T) {
	{
		db, eng, clock, mClock, _, transport, err := createTestDB()
		if err != nil {
			t.Fatal(err)
		}
		defer transport.Close()
		// Set a large offset so that a busy restart-loop
		// really shows. Also makes sure that the values
		// we write in the future below don't actually
		// wind up in the past.
		offset := 4000 * time.Millisecond
		clock.SetMaxOffset(offset)
		key := proto.Key("key")
		value := proto.Value{
			Bytes: nil, // Set for each Put
		}
		// With the correct restart behaviour, we see only one restart
		// and the value read is the very first one (as nothing else
		// has been written)
		wantedBytes := []byte("value-0")

		txnOpts := &client.TransactionOptions{
			Name: "uncertainty",
		}
		gr := &proto.GetResponse{}
		i := -1
		tErr := db.RunTransaction(txnOpts, func(txn *client.KV) error {
			i++
			mClock.Increment(1)
			futureTS := clock.Now()
			futureTS.WallTime++
			value.Bytes = []byte(fmt.Sprintf("value-%d", i))
			err = engine.MVCCPut(eng, nil, key, futureTS, value, nil)
			if err != nil {
				t.Fatal(err)
			}
			gr.Reset()
			if err := txn.Call(proto.Get, proto.GetArgs(key), gr); err != nil {
				return err
			}
			if gr.Value == nil || !bytes.Equal(gr.Value.Bytes, wantedBytes) {
				t.Fatalf("%d: read wrong value: %v, wanted %q", i,
					gr.Value, wantedBytes)
			}
			return nil
		})
		if i != 1 {
			t.Errorf("txn restarted %d times, expected only one restart", i)
		}
		if tErr != nil {
			t.Fatal(tErr)
		}
	}
}

// PreparePutProto sets the given key to the protobuf-serialized byte
// string of msg. The resulting Put call is buffered and will not be
// sent until a subsequent call to Flush. Returns marshalling errors
// if encountered.
func (kv *KV) PreparePutProto(key proto.Key, msg gogoproto.Message) error {
	data, err := gogoproto.Marshal(msg)
	if err != nil {
		return err
	}
	value := proto.Value{Bytes: data}
	value.InitChecksum(key)
	kv.Prepare(proto.Put, &proto.PutRequest{
		RequestHeader: proto.RequestHeader{Key: key},
		Value:         value,
	}, &proto.PutResponse{})
	return nil
}

// setupMVCCData writes up to numVersions values at each of numKeys
// keys. The number of versions written for each key is chosen
// randomly according to a uniform distribution. Each successive
// version is written starting at 5ns and then in 5ns increments. This
// allows scans at various times, starting at t=5ns, and continuing to
// t=5ns*(numVersions+1). A version for each key will be read on every
// such scan, but the dynamics of the scan will change depending on
// the historical timestamp. Earlier timestamps mean scans which must
// skip more historical versions; later timestamps mean scans which
// skip fewer.
//
// The creation of the rocksdb database is time consuming, especially
// for larger numbers of versions. The database is persisted between
// runs and stored in the current directory as
// "mvcc_scan_<versions>_<keys>".
func setupMVCCScanData(numVersions, numKeys int, b *testing.B) (*RocksDB, *stop.Stopper) {
	loc := fmt.Sprintf("mvcc_scan_%d_%d", numVersions, numKeys)

	exists := true
	if _, err := os.Stat(loc); os.IsNotExist(err) {
		exists = false
	}

	log.Infof("creating mvcc data: %s", loc)
	const cacheSize = 8 << 30 // 8 GB
	stopper := stop.NewStopper()
	rocksdb := NewRocksDB(proto.Attributes{Attrs: []string{"ssd"}}, loc, cacheSize, stopper)
	if err := rocksdb.Open(); err != nil {
		b.Fatalf("could not create new rocksdb db instance at %s: %v", loc, err)
	}

	if exists {
		return rocksdb, stopper
	}

	rng, _ := randutil.NewPseudoRand()
	keys := make([]proto.Key, numKeys)
	nvs := make([]int, numKeys)
	for t := 1; t <= numVersions; t++ {
		walltime := int64(5 * t)
		ts := makeTS(walltime, 0)
		batch := rocksdb.NewBatch()
		for i := 0; i < numKeys; i++ {
			if t == 1 {
				keys[i] = proto.Key(encoding.EncodeUvarint([]byte("key-"), uint64(i)))
				nvs[i] = int(rand.Int31n(int32(numVersions)) + 1)
			}
			// Only write values if this iteration is less than the random
			// number of versions chosen for this key.
			if t <= nvs[i] {
				value := proto.Value{Bytes: randutil.RandBytes(rng, 1024)}
				value.InitChecksum(keys[i])
				if err := MVCCPut(batch, nil, keys[i], ts, value, nil); err != nil {
					b.Fatal(err)
				}
			}
		}
		if err := batch.Commit(); err != nil {
			b.Fatal(err)
		}
		batch.Close()
	}
	rocksdb.CompactRange(nil, nil)

	return rocksdb, stopper
}

// Indirectly this tests that the transaction remembers the NodeID of the node
// being read from correctly, at least in this simple case. Not remembering the
// node would lead to thousands of transaction restarts and almost certainly a
// test timeout.
func TestUncertaintyRestarts(t *testing.T) {
	defer leaktest.AfterTest(t)
	s := createTestDB(t)
	defer s.Stop()
	// Set a large offset so that a busy restart-loop
	// really shows. Also makes sure that the values
	// we write in the future below don't actually
	// wind up in the past.
	offset := 4000 * time.Millisecond
	s.Clock.SetMaxOffset(offset)
	key := proto.Key("key")
	value := proto.Value{
		Bytes: nil, // Set for each Put
	}
	// With the correct restart behaviour, we see only one restart
	// and the value read is the very first one (as nothing else
	// has been written)
	wantedBytes := []byte("value-0")

	i := -1
	tErr := s.DB.Txn(func(txn *client.Txn) error {
		i++
		s.Manual.Increment(1)
		futureTS := s.Clock.Now()
		futureTS.WallTime++
		value.Bytes = []byte(fmt.Sprintf("value-%d", i))
		if err := engine.MVCCPut(s.Eng, nil, key, futureTS, value, nil); err != nil {
			t.Fatal(err)
		}
		gr, err := txn.Get(key)
		if err != nil {
			return err
		}
		if !gr.Exists() || !bytes.Equal(gr.ValueBytes(), wantedBytes) {
			t.Fatalf("%d: read wrong value: %v, wanted %q", i, gr.Value, wantedBytes)
		}
		return nil
	})
	if i != 1 {
		t.Errorf("txn restarted %d times, expected only one restart", i)
	}
	if tErr != nil {
		t.Fatal(tErr)
	}
}

// GetInitialSystemValues returns a list of key/value pairs.
// They are written at cluster bootstrap time (see storage/node.go:BootstrapCLuster).
func GetInitialSystemValues() []proto.KeyValue {
	systemData := []struct {
		parentID ID
		desc     descriptorProto
	}{
		{keys.RootNamespaceID, &SystemDB},
		{SystemDB.ID, &NamespaceTable},
		{SystemDB.ID, &DescriptorTable},
		{SystemDB.ID, &UsersTable},
		{SystemDB.ID, &ZonesTable},
	}

	// Initial kv pairs:
	// - ID generator
	// - 2 per table/database
	numEntries := 1 + len(systemData)*2
	ret := make([]proto.KeyValue, numEntries, numEntries)
	i := 0

	// Descriptor ID generator.
	value := proto.Value{}
	value.SetInt(int64(keys.MaxReservedDescID + 1))
	ret[i] = proto.KeyValue{
		Key:   keys.DescIDGenerator,
		Value: value,
	}
	i++

	// System database and tables.
	for _, d := range systemData {
		value = proto.Value{}
		value.SetInt(int64(d.desc.GetID()))
		ret[i] = proto.KeyValue{
			Key:   MakeNameMetadataKey(d.parentID, d.desc.GetName()),
			Value: value,
		}
		i++

		value = proto.Value{}
		if err := value.SetProto(d.desc); err != nil {
			log.Fatalf("could not marshal %v", d.desc)
		}
		ret[i] = proto.KeyValue{
			Key:   MakeDescMetadataKey(d.desc.GetID()),
			Value: value,
		}
		i++
	}

	return ret
}

// marshalValue returns a proto.Value initialized from the source
// reflect.Value, returning an error if the types are not compatible.
func marshalValue(v interface{}) (proto.Value, error) {
	var r proto.Value
	if v == nil {
		return r, nil
	}

	switch t := v.(type) {
	case nil:
		return r, nil

	case string:
		r.SetBytes([]byte(t))
		return r, nil

	case []byte:
		r.SetBytes(t)
		return r, nil

	case proto.Key:
		r.SetBytes([]byte(t))
		return r, nil

	case time.Time:
		err := r.SetTime(t)
		return r, err

	case gogoproto.Message:
		err := r.SetProto(t)
		return r, err
	}

	switch v := reflect.ValueOf(v); v.Kind() {
	case reflect.Bool:
		i := int64(0)
		if v.Bool() {
			i = 1
		}
		r.SetInt(i)
		return r, nil

	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		r.SetInt(v.Int())
		return r, nil

	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		r.SetInt(int64(v.Uint()))
		return r, nil

	case reflect.Float32, reflect.Float64:
		r.SetFloat(v.Float())
		return r, nil

	case reflect.String:
		r.SetBytes([]byte(v.String()))
		return r, nil
	}

	return r, fmt.Errorf("unable to marshal value: %s", v)
}

// marshalValue returns a proto.Value initialized from the source
// reflect.Value, returning an error if the types are not compatible.
func marshalValue(v reflect.Value) (proto.Value, error) {
	var r proto.Value
	if !v.IsValid() {
		return r, nil
	}

	switch t := v.Interface().(type) {
	case nil:
		return r, nil

	case string:
		r.Bytes = []byte(t)
		return r, nil

	case []byte:
		r.Bytes = t
		return r, nil

	case proto.Key:
		r.Bytes = []byte(t)
		return r, nil

	case gogoproto.Message:
		var err error
		r.Bytes, err = gogoproto.Marshal(t)
		return r, err

	case encoding.BinaryMarshaler:
		var err error
		r.Bytes, err = t.MarshalBinary()
		return r, err
	}

	switch v.Kind() {
	case reflect.Bool:
		i := int64(0)
		if v.Bool() {
			i = 1
		}
		r.SetInteger(i)
		return r, nil

	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		r.SetInteger(v.Int())
		return r, nil

	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		r.SetInteger(int64(v.Uint()))
		return r, nil

	case reflect.Float32, reflect.Float64:
		r.SetInteger(int64(math.Float64bits(v.Float())))
		return r, nil

	case reflect.String:
		r.Bytes = []byte(v.String())
		return r, nil
	}

	return r, fmt.Errorf("unable to marshal value: %s", v)
}

// unmarshalValue sets the destination reflect.Value contents from the source
// proto.Value, returning an error if the types are not compatible.
func unmarshalValue(src *proto.Value, dest reflect.Value) error {
	if src == nil {
		dest.Set(reflect.Zero(dest.Type()))
		return nil
	}

	switch d := dest.Addr().Interface().(type) {
	case *string:
		if src.Bytes != nil {
			*d = string(src.Bytes)
		} else {
			*d = ""
		}
		return nil

	case *[]byte:
		if src.Bytes != nil {
			*d = src.Bytes
		} else {
			*d = nil
		}
		return nil

	case *gogoproto.Message:
		panic("TODO(pmattis): unimplemented")

	case *encoding.BinaryUnmarshaler:
		return (*d).UnmarshalBinary(src.Bytes)
	}

	switch dest.Kind() {
	case reflect.Bool:
		i, err := src.GetInteger()
		if err != nil {
			return err
		}
		dest.SetBool(i != 0)
		return nil

	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		i, err := src.GetInteger()
		if err != nil {
			return err
		}
		dest.SetInt(i)
		return nil

	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		i, err := src.GetInteger()
		if err != nil {
			return err
		}
		dest.SetUint(uint64(i))
		return nil

	case reflect.Float32, reflect.Float64:
		i, err := src.GetInteger()
		if err != nil {
			return err
		}
		dest.SetFloat(math.Float64frombits(uint64(i)))
		return nil

	case reflect.String:
		if src == nil || src.Bytes == nil {
			dest.SetString("")
			return nil
		}
		dest.SetString(string(src.Bytes))
		return nil
	}

	return fmt.Errorf("unable to unmarshal value: %s", dest.Type())
}

// unmarshalColumnValue decodes the value from a key-value pair using the type
// expected by the column. An error is returned if the value's type does not
// match the column's type.
func unmarshalColumnValue(kind ColumnType_Kind, value *proto.Value) (parser.Datum, error) {
	if value == nil {
		return parser.DNull, nil
	}

	switch kind {
	case ColumnType_BOOL:
		v, err := value.GetInt()
		if err != nil {
			return nil, err
		}
		return parser.DBool(v != 0), nil
	case ColumnType_INT:
		v, err := value.GetInt()
		if err != nil {
			return nil, err
		}
		return parser.DInt(v), nil
	case ColumnType_FLOAT:
		v, err := value.GetFloat()
		if err != nil {
			return nil, err
		}
		return parser.DFloat(v), nil
	case ColumnType_STRING:
		v, err := value.GetBytesChecked()
		if err != nil {
			return nil, err
		}
		return parser.DString(v), nil
	case ColumnType_BYTES:
		v, err := value.GetBytesChecked()
		if err != nil {
			return nil, err
		}
		return parser.DBytes(v), nil
	case ColumnType_DATE:
		v, err := value.GetTime()
		if err != nil {
			return nil, err
		}
		return parser.DDate{Time: v}, nil
	case ColumnType_TIMESTAMP:
		v, err := value.GetTime()
		if err != nil {
			return nil, err
		}
		return parser.DTimestamp{Time: v}, nil
	case ColumnType_INTERVAL:
		v, err := value.GetInt()
		if err != nil {
			return nil, err
		}
		return parser.DInterval{Duration: time.Duration(v)}, nil
	default:
		return nil, util.Errorf("unsupported column type: %s", kind)
	}
}

// marshalValue returns a proto.Value initialized from the source
// interface{}, returning an error if the types are not compatible.
func marshalValue(v interface{}) (proto.Value, error) {
	var r proto.Value

	// Handle a few common types via a type switch.
	switch t := v.(type) {
	case nil:
		return r, nil

	case bool:
		i := int64(0)
		if t {
			i = 1
		}
		r.SetInt(i)
		return r, nil

	case string:
		r.SetBytes([]byte(t))
		return r, nil

	case []byte:
		r.SetBytes(t)
		return r, nil

	case proto.Key:
		r.SetBytes([]byte(t))
		return r, nil

	case time.Time:
		r.SetTime(t)
		return r, nil

	case gogoproto.Message:
		err := r.SetProto(t)
		return r, err
	}

	// Handle all of the Go primitive types besides struct and pointers. This
	// switch also handles types based on a primitive type (e.g. "type MyInt
	// int").
	switch v := reflect.ValueOf(v); v.Kind() {
	case reflect.Bool:
		i := int64(0)
		if v.Bool() {
			i = 1
		}
		r.SetInt(i)
		return r, nil

	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		r.SetInt(v.Int())
		return r, nil

	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		r.SetInt(int64(v.Uint()))
		return r, nil

	case reflect.Float32, reflect.Float64:
		r.SetFloat(v.Float())
		return r, nil

	case reflect.String:
		r.SetBytes([]byte(v.String()))
		return r, nil
	}

	return r, fmt.Errorf("unable to marshal value: %s", v)
}