mirror of https://github.com/poanetwork/gecko.git
64 lines
1.7 KiB
Go
64 lines
1.7 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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)
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// binarySnowflake is the implementation of a binary snowflake instance
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type binarySnowflake struct {
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// wrap the binary slush logic
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binarySlush
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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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// beta is the number of consecutive successful queries required for
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// finalization.
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beta int
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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 BinarySnowflake interface
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func (sf *binarySnowflake) Initialize(beta, choice int) {
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sf.binarySlush.Initialize(choice)
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sf.beta = beta
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}
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// RecordSuccessfulPoll implements the BinarySnowflake interface
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func (sf *binarySnowflake) RecordSuccessfulPoll(choice int) {
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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 == 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.confidence >= sf.beta
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sf.binarySlush.RecordSuccessfulPoll(choice)
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}
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// RecordUnsuccessfulPoll implements the BinarySnowflake interface
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func (sf *binarySnowflake) RecordUnsuccessfulPoll() { sf.confidence = 0 }
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// Finalized implements the BinarySnowflake interface
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func (sf *binarySnowflake) Finalized() bool { return sf.finalized }
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func (sf *binarySnowflake) 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.binarySlush)
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}
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