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Documentation
¶
Overview ¶
Package ttlcache provides an ExpiryHeap that can be used by a cache to track the expiration time of its entries. When an expiry is reached the Timer will fire and the entry can be removed.
Index ¶
Constants ¶
const NotIndexed = -1
NotIndexed indicates that the entry does not exist in the heap. Either because it is nil, or because it was removed.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Entry ¶
type Entry struct {
// contains filtered or unexported fields
}
Entry in the ExpiryHeap, tracks the index and expiry time of an item in a ttl cache.
type ExpiryHeap ¶
type ExpiryHeap struct {
// NotifyCh is sent a value whenever the 0 index value of the heap
// changes. This can be used to detect when the earliest value
// changes.
NotifyCh chan struct{}
// contains filtered or unexported fields
}
ExpiryHeap is a heap that is ordered by the expiry time of entries. It may be used by a cache or storage to expiry items after a TTL.
ExpiryHeap expects the caller to synchronize calls to most of its methods. This is necessary because the cache needs to ensure that updates to both its storage and the ExpiryHeap are synchronized.
func NewExpiryHeap ¶
func NewExpiryHeap() *ExpiryHeap
NewExpiryHeap creates and returns a new ExpiryHeap.
func (*ExpiryHeap) Add ¶
func (h *ExpiryHeap) Add(key string, expiry time.Duration) *Entry
Add an entry to the heap.
Must be synchronized by the caller.
func (*ExpiryHeap) Next ¶
func (h *ExpiryHeap) Next() Timer
Next returns a Timer that waits until the first entry in the heap expires.
Must be synchronized by the caller.
func (*ExpiryHeap) Remove ¶
func (h *ExpiryHeap) Remove(idx int)
Remove the entry at idx from the heap.
Must be synchronized by the caller.
func (*ExpiryHeap) Update ¶
func (h *ExpiryHeap) Update(idx int, expiry time.Duration)
Update the entry that is currently at idx with the new expiry time, if the new expiry time is further into the future. The heap will be rebalanced after the entry is updated. If the new expiry time is earlier than the existing expiry time than the expiry is not modified.
Must be synchronized by the caller.
type Timer ¶
type Timer struct {
Entry *Entry
// contains filtered or unexported fields
}
Timer provides a channel to block on. When the Wait channel receives an item the Timer.Entry has expired. The caller is expected to call ExpiryHeap.Remove with the Entry.Index().
The caller is responsible for calling Stop to stop the timer if the timer has not fired.
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