77 lines
2.2 KiB
Go
77 lines
2.2 KiB
Go
// Copyright 2013 Prometheus Team
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package storage
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// RecordDecoder decodes each key-value pair in the database. The protocol
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// around it makes the assumption that the underlying implementation is
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// concurrency safe.
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type RecordDecoder interface {
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DecodeKey(in interface{}) (out interface{}, err error)
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DecodeValue(in interface{}) (out interface{}, err error)
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}
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// FilterResult describes the record matching and scanning behavior for the
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// database.
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type FilterResult int
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const (
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// Stop scanning the database.
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STOP FilterResult = iota
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// Skip this record but continue scanning.
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SKIP
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// Accept this record for the Operator.
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ACCEPT
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)
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func (f FilterResult) String() string {
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switch f {
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case STOP:
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return "STOP"
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case SKIP:
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return "SKIP"
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case ACCEPT:
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return "ACCEPT"
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}
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panic("unknown")
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}
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type OperatorErrorType int
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type OperatorError struct {
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error
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Continuable bool
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}
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// Filter is responsible for controlling the behavior of the database scan
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// process and determines the disposition of various records.
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//
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// The protocol around it makes the assumption that the underlying
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// implementation is concurrency safe.
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type RecordFilter interface {
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// Filter receives the key and value as decoded from the RecordDecoder type.
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Filter(key, value interface{}) (filterResult FilterResult)
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}
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// RecordOperator is responsible for taking action upon each entity that is
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// passed to it.
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//
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// The protocol around it makes the assumption that the underlying
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// implementation is concurrency safe.
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type RecordOperator interface {
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// Take action on a given record. If the action returns an error, the entire
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// scan process stops.
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Operate(key, value interface{}) (err *OperatorError)
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}
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