tasks/common/persistence/jsonHistoryTokenSerializer.go

// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package persistence

import "encoding/json"

type (
	jsonHistoryTokenSerializer struct{}

	// historyPagingToken is used to serialize/deserialize pagination token for ReadHistoryBranchRequest
	historyPagingToken struct {
		LastEventID int64
		// the pagination token passing to persistence
		StoreToken []byte
		// recording which branchRange it is reading
		CurrentRangeIndex int
		FinalRangeIndex   int

		// LastNodeID is the last known node ID attached to a history node
		LastNodeID int64
		// LastTransactionID is the last known transaction ID attached to a history node
		LastTransactionID int64
	}
)

const notStartedIndex = -1

// newJSONHistoryTokenSerializer creates a new instance of TaskTokenSerializer
func newJSONHistoryTokenSerializer() *jsonHistoryTokenSerializer {
	return &jsonHistoryTokenSerializer{}
}

func (t *historyPagingToken) SetRangeIndexes(
	current int,
	final int,
) {

	t.CurrentRangeIndex = current
	t.FinalRangeIndex = final
}

func (j *jsonHistoryTokenSerializer) Serialize(
	token *historyPagingToken,
) ([]byte, error) {

	data, err := json.Marshal(token)
	return data, err
}

func (j *jsonHistoryTokenSerializer) Deserialize(
	data []byte,
	defaultLastEventID int64,
	defaultLastNodeID int64,
	defaultLastTransactionID int64,
) (*historyPagingToken, error) {

	if len(data) == 0 {
		token := historyPagingToken{
			LastEventID:       defaultLastEventID,
			CurrentRangeIndex: notStartedIndex,
			LastNodeID:        defaultLastNodeID,
			LastTransactionID: defaultLastTransactionID,
		}
		return &token, nil
	}

	token := historyPagingToken{}
	err := json.Unmarshal(data, &token)
	return &token, err
}