forked from mystiq/dex
75 lines
2.3 KiB
Go
75 lines
2.3 KiB
Go
// Copyright 2019 The etcd 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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package quorum
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// JointConfig is a configuration of two groups of (possibly overlapping)
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// majority configurations. Decisions require the support of both majorities.
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type JointConfig [2]MajorityConfig
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func (c JointConfig) String() string {
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if len(c[1]) > 0 {
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return c[0].String() + "&&" + c[1].String()
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}
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return c[0].String()
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}
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// IDs returns a newly initialized map representing the set of voters present
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// in the joint configuration.
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func (c JointConfig) IDs() map[uint64]struct{} {
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m := map[uint64]struct{}{}
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for _, cc := range c {
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for id := range cc {
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m[id] = struct{}{}
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}
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}
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return m
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}
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// Describe returns a (multi-line) representation of the commit indexes for the
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// given lookuper.
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func (c JointConfig) Describe(l AckedIndexer) string {
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return MajorityConfig(c.IDs()).Describe(l)
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}
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// CommittedIndex returns the largest committed index for the given joint
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// quorum. An index is jointly committed if it is committed in both constituent
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// majorities.
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func (c JointConfig) CommittedIndex(l AckedIndexer) Index {
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idx0 := c[0].CommittedIndex(l)
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idx1 := c[1].CommittedIndex(l)
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if idx0 < idx1 {
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return idx0
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}
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return idx1
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}
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// VoteResult takes a mapping of voters to yes/no (true/false) votes and returns
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// a result indicating whether the vote is pending, lost, or won. A joint quorum
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// requires both majority quorums to vote in favor.
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func (c JointConfig) VoteResult(votes map[uint64]bool) VoteResult {
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r1 := c[0].VoteResult(votes)
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r2 := c[1].VoteResult(votes)
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if r1 == r2 {
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// If they agree, return the agreed state.
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return r1
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}
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if r1 == VoteLost || r2 == VoteLost {
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// If either config has lost, loss is the only possible outcome.
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return VoteLost
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}
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// One side won, the other one is pending, so the whole outcome is.
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return VotePending
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}
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