49 lines
1.5 KiB
Go
49 lines
1.5 KiB
Go
package timecache
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import (
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"time"
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)
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// Stategy is the TimeCache expiration strategy to use.
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type Strategy uint8
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const (
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// Strategy_FirstSeen expires an entry from the time it was added.
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Strategy_FirstSeen Strategy = iota
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// Stategy_LastSeen expires an entry from the last time it was touched by an Add or Has.
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Strategy_LastSeen
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)
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// TimeCache is a cahe of recently seen messages (by id).
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type TimeCache interface {
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// Add adds an id into the cache, if it is not already there.
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// Returns true if the id was newly added to the cache.
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// Depending on the implementation strategy, it may or may not update the expiry of
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// an existing entry.
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Add(string) bool
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// Has checks the cache for the presence of an id.
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// Depending on the implementation strategy, it may or may not update the expiry of
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// an existing entry.
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Has(string) bool
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// Done signals that the user is done with this cache, which it may stop background threads
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// and relinquish resources.
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Done()
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}
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// NewTimeCache defaults to the original ("first seen") cache implementation
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func NewTimeCache(ttl time.Duration) TimeCache {
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return NewTimeCacheWithStrategy(Strategy_FirstSeen, ttl)
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}
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func NewTimeCacheWithStrategy(strategy Strategy, ttl time.Duration) TimeCache {
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switch strategy {
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case Strategy_FirstSeen:
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return newFirstSeenCache(ttl)
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case Strategy_LastSeen:
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return newLastSeenCache(ttl)
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default:
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// Default to the original time cache implementation
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return newFirstSeenCache(ttl)
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}
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}
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