mirror of https://github.com/tikv/client-go.git
114 lines
3.4 KiB
Go
114 lines
3.4 KiB
Go
// Copyright 2022 TiKV Authors
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//
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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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// NOTE: The code in this file is based on code from the
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// TiDB project, licensed under the Apache License v 2.0
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//
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// https://github.com/pingcap/tidb/tree/cc5e161ac06827589c4966674597c137cc9e809c/store/tikv/locate/region_request.go
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//
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// Copyright 2016 PingCAP, Inc.
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//
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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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//go:build go1.18
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// +build go1.18
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package locate
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import (
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"bytes"
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"github.com/google/btree"
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)
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// SortedRegions is a sorted btree.
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type SortedRegions struct {
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b *btree.BTreeG[*btreeItem]
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}
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// NewSortedRegions returns a new SortedRegions.
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func NewSortedRegions(btreeDegree int) *SortedRegions {
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return &SortedRegions{
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b: btree.NewG(btreeDegree, func(a, b *btreeItem) bool { return a.Less(b) }),
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}
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}
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// ReplaceOrInsert inserts a new item into the btree.
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func (s *SortedRegions) ReplaceOrInsert(cachedRegion *Region) *Region {
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old, _ := s.b.ReplaceOrInsert(newBtreeItem(cachedRegion))
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if old != nil {
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return old.cachedRegion
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}
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return nil
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}
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// DescendLessOrEqual returns all items that are less than or equal to the key.
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func (s *SortedRegions) DescendLessOrEqual(key []byte, isEndKey bool, ts int64) (r *Region) {
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s.b.DescendLessOrEqual(newBtreeSearchItem(key), func(item *btreeItem) bool {
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r = item.cachedRegion
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if isEndKey && bytes.Equal(r.StartKey(), key) {
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r = nil // clear result
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return true // iterate next item
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}
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if !r.checkRegionCacheTTL(ts) {
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r = nil
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return true
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}
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return false
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})
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return r
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}
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// AscendGreaterOrEqual returns all items that are greater than or equal to the key.
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func (s *SortedRegions) AscendGreaterOrEqual(startKey, endKey []byte, limit int) (regions []*Region) {
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s.b.AscendGreaterOrEqual(newBtreeSearchItem(startKey), func(item *btreeItem) bool {
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region := item.cachedRegion
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if len(endKey) > 0 && bytes.Compare(region.StartKey(), endKey) >= 0 {
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return false
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}
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regions = append(regions, region)
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return len(regions) < limit
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})
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return regions
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}
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// Clear removes all items from the btree.
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func (s *SortedRegions) Clear() {
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s.b.Clear(false)
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}
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// ValidRegionsInBtree returns the number of valid regions in the btree.
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func (s *SortedRegions) ValidRegionsInBtree(ts int64) (len int) {
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s.b.Descend(func(item *btreeItem) bool {
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r := item.cachedRegion
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if !r.checkRegionCacheTTL(ts) {
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return true
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}
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len++
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return true
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})
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return
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}
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