mirror of https://github.com/poanetwork/gecko.git
79 lines
2.3 KiB
Go
79 lines
2.3 KiB
Go
// (c) 2019-2020, Ava Labs, Inc. All rights reserved.
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// See the file LICENSE for licensing terms.
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package snowball
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import (
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"fmt"
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"github.com/ava-labs/gecko/ids"
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)
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// nnarySnowflake is the implementation of a snowflake instance with an
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// unbounded number of choices
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type nnarySnowflake struct {
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// wrap the n-nary slush logic
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nnarySlush
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// betaVirtuous is the number of consecutive successful queries required for
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// finalization on a virtuous instance.
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betaVirtuous int
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// betaRogue is the number of consecutive successful queries required for
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// finalization on a rogue instance.
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betaRogue int
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// confidence tracks the number of successful polls in a row that have
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// returned the preference
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confidence int
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// rogue tracks if this instance has multiple choices or only one
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rogue bool
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// finalized prevents the state from changing after the required number of
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// consecutive polls has been reached
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finalized bool
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}
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// Initialize implements the NnarySnowflake interface
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func (sf *nnarySnowflake) Initialize(betaVirtuous, betaRogue int, choice ids.ID) {
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sf.nnarySlush.Initialize(choice)
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sf.betaVirtuous = betaVirtuous
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sf.betaRogue = betaRogue
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}
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// Add implements the NnarySnowflake interface
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func (sf *nnarySnowflake) Add(choice ids.ID) { sf.rogue = sf.rogue || !choice.Equals(sf.preference) }
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// RecordSuccessfulPoll implements the NnarySnowflake interface
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func (sf *nnarySnowflake) RecordSuccessfulPoll(choice ids.ID) {
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if sf.finalized {
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return // This instace is already decided.
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}
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if preference := sf.Preference(); preference.Equals(choice) {
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sf.confidence++
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} else {
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// confidence is set to 1 because there has already been 1 successful
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// poll, namely this poll.
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sf.confidence = 1
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}
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sf.finalized = (!sf.rogue && sf.confidence >= sf.betaVirtuous) ||
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sf.confidence >= sf.betaRogue
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sf.nnarySlush.RecordSuccessfulPoll(choice)
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}
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// RecordUnsuccessfulPoll implements the NnarySnowflake interface
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func (sf *nnarySnowflake) RecordUnsuccessfulPoll() { sf.confidence = 0 }
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// Finalized implements the NnarySnowflake interface
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func (sf *nnarySnowflake) Finalized() bool { return sf.finalized }
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func (sf *nnarySnowflake) String() string {
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return fmt.Sprintf("SF(Confidence = %d, Finalized = %v, %s)",
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sf.confidence,
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sf.finalized,
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&sf.nnarySlush)
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}
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