52 lines
1.6 KiB
Go
52 lines
1.6 KiB
Go
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// Licensed to Elasticsearch B.V. under one or more contributor
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// license agreements. See the NOTICE file distributed with
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// this work for additional information regarding copyright
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// ownership. Elasticsearch B.V. licenses this file to you under
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// the Apache License, Version 2.0 (the "License"); you may
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// 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,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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package common
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import (
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"sync/atomic"
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"unsafe"
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)
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// MapStrPointer stores a pointer to atomically get/set a MapStr object
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// This should give faster access for use cases with lots of reads and a few
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// changes.
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// It's important to note that modifying the map is not thread safe, only fully
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// replacing it.
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type MapStrPointer struct {
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p *unsafe.Pointer
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}
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// NewMapStrPointer initializes and returns a pointer to the given MapStr
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func NewMapStrPointer(m MapStr) MapStrPointer {
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pointer := unsafe.Pointer(&m)
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return MapStrPointer{p: &pointer}
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}
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// Get returns the MapStr stored under this pointer
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func (m MapStrPointer) Get() MapStr {
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if m.p == nil {
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return nil
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}
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return *(*MapStr)(atomic.LoadPointer(m.p))
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}
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// Set stores a pointer the given MapStr, replacing any previous one
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func (m *MapStrPointer) Set(p MapStr) {
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atomic.StorePointer(m.p, unsafe.Pointer(&p))
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}
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