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63 lines
1.4 KiB
63 lines
1.4 KiB
package p2p
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import "time"
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// Backoff is a backoff sleeper.
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type Backoff interface {
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Reset()
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Sleep()
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Backoff()
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}
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// BackoffBase is the base implementation of backoff sleeper. It handles the
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// minimum/current/maximum backoff logic. If maximum backoff is 0, there is no
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// maximum.
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type BackoffBase struct {
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Min, Cur, Max time.Duration
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}
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// NewBackoffBase creates a new BackOffBase structure
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func NewBackoffBase(min, max time.Duration) *BackoffBase {
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return &BackoffBase{min, min, max}
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}
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// Reset the current sleep duration to its minimum value.
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func (b *BackoffBase) Reset() {
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b.Cur = b.Min
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}
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// Sleep for the current duration, then adjust the duration.
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func (b *BackoffBase) Sleep() {
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if b.Cur < b.Min {
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b.Cur = b.Min
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}
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time.Sleep(b.Cur)
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b.Backoff()
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if b.Max != 0 && b.Cur > b.Max {
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b.Cur = b.Max
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}
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if b.Cur < b.Min {
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b.Cur = b.Min
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}
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}
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// Backoff adjusts the duration. Subtypes shall implement this.
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func (b *BackoffBase) Backoff() {
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// default implementation does not backoff
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}
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// ExpBackoff is an exponential backoff data structure.
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type ExpBackoff struct {
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BackoffBase
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Factor float64
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}
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// NewExpBackoff creates a new ExpBackOff structure
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func NewExpBackoff(min, max time.Duration, factor float64) *ExpBackoff {
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return &ExpBackoff{*NewBackoffBase(min, max), factor}
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}
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// Backoff implements the exponential backoff
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func (b *ExpBackoff) Backoff() {
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b.Cur = time.Duration(float64(b.Cur) * b.Factor)
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}
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