63 lines
1.8 KiB
Go
63 lines
1.8 KiB
Go
/*
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Copyright 2018 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package node
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// intSet maintains a set of ints, and supports promoting and culling the previous generation.
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// this allows tracking a large, mostly-stable set without constantly reallocating the entire set.
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type intSet struct {
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currentGeneration byte
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members map[int]byte
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}
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func newIntSet() *intSet {
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return &intSet{members: map[int]byte{}}
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}
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// has returns true if the specified int is in the set.
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// it is safe to call concurrently, but must not be called concurrently with any of the other methods.
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func (s *intSet) has(i int) bool {
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if s == nil {
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return false
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}
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_, present := s.members[i]
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return present
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}
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// startNewGeneration begins a new generation.
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// it must be followed by a call to mark() for every member of the generation,
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// then a call to sweep() to remove members not present in the generation.
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// it is not thread-safe.
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func (s *intSet) startNewGeneration() {
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s.currentGeneration++
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}
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// mark indicates the specified int belongs to the current generation.
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// it is not thread-safe.
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func (s *intSet) mark(i int) {
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s.members[i] = s.currentGeneration
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}
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// sweep removes items not in the current generation.
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// it is not thread-safe.
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func (s *intSet) sweep() {
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for k, v := range s.members {
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if v != s.currentGeneration {
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delete(s.members, k)
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}
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}
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}
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