go-client/pegasus/check_and_set.go

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package pegasus

import "github.com/apache/incubator-pegasus/go-client/idl/rrdb"

// CheckType defines the types of value checking in a CAS.
type CheckType int

// The value checking types
const (
	CheckTypeNoCheck = CheckType(rrdb.CasCheckType_CT_NO_CHECK)

	// existence
	CheckTypeValueNotExist        = CheckType(rrdb.CasCheckType_CT_VALUE_NOT_EXIST)          // value is not exist
	CheckTypeValueNotExistOrEmpty = CheckType(rrdb.CasCheckType_CT_VALUE_NOT_EXIST_OR_EMPTY) // value is not exist or value is empty
	CheckTypeValueExist           = CheckType(rrdb.CasCheckType_CT_VALUE_EXIST)              // value is exist
	CheckTypeValueNotEmpty        = CheckType(rrdb.CasCheckType_CT_VALUE_NOT_EMPTY)          // value is exist and not empty

	// match
	CheckTypeMatchAnywhere = CheckType(rrdb.CasCheckType_CT_VALUE_MATCH_ANYWHERE) // operand matches anywhere in value
	CheckTypeMatchPrefix   = CheckType(rrdb.CasCheckType_CT_VALUE_MATCH_PREFIX)   // operand matches prefix in value
	CheckTypeMatchPostfix  = CheckType(rrdb.CasCheckType_CT_VALUE_MATCH_POSTFIX)  // operand matches postfix in value

	// bytes compare
	CheckTypeBytesLess           = CheckType(rrdb.CasCheckType_CT_VALUE_BYTES_LESS)             // bytes compare: value < operand
	CheckTypeBytesLessOrEqual    = CheckType(rrdb.CasCheckType_CT_VALUE_BYTES_LESS_OR_EQUAL)    // bytes compare: value <= operand
	CheckTypeBytesEqual          = CheckType(rrdb.CasCheckType_CT_VALUE_BYTES_EQUAL)            // bytes compare: value == operand
	CheckTypeBytesGreaterOrEqual = CheckType(rrdb.CasCheckType_CT_VALUE_BYTES_GREATER_OR_EQUAL) // bytes compare: value >= operand
	CheckTypeBytesGreater        = CheckType(rrdb.CasCheckType_CT_VALUE_BYTES_GREATER)          // bytes compare: value > operand

	// int compare: first transfer bytes to int64; then compare by int value
	CheckTypeIntLess           = CheckType(rrdb.CasCheckType_CT_VALUE_INT_LESS)             // int compare: value < operand
	CheckTypeIntLessOrEqual    = CheckType(rrdb.CasCheckType_CT_VALUE_INT_LESS_OR_EQUAL)    // int compare: value <= operand
	CheckTypeIntEqual          = CheckType(rrdb.CasCheckType_CT_VALUE_INT_EQUAL)            // int compare: value == operand
	CheckTypeIntGreaterOrEqual = CheckType(rrdb.CasCheckType_CT_VALUE_INT_GREATER_OR_EQUAL) // int compare: value >= operand
	CheckTypeIntGreater        = CheckType(rrdb.CasCheckType_CT_VALUE_BYTES_GREATER)        // int compare: value > operand
)

// CheckAndSetResult is the result of a CAS.
type CheckAndSetResult struct {
	// true if set value succeed.
	SetSucceed bool

	// the actual value if set value failed; null means the actual value is not exist.
	CheckValue []byte

	// if the check value is exist; can be used only when checkValueReturned is true.
	CheckValueExist bool

	// return the check value if exist; can be used only when checkValueExist is true.
	CheckValueReturned bool
}

// CheckAndSetOptions is the options of a CAS.
type CheckAndSetOptions struct {
	SetValueTTLSeconds int  // time to live in seconds of the set value, 0 means no ttl.
	ReturnCheckValue   bool // if return the check value in results.
}