lru_cache.go

Documentation: github.com/launchdarkly/go-sdk-events/v2

     1  package ldevents
     2  
     3  import (
     4  	"container/list"
     5  )
     6  
     7  type lruCache struct {
     8  	values   map[interface{}]*list.Element
     9  	lruList  *list.List
    10  	capacity int
    11  }
    12  
    13  func newLruCache(capacity int) lruCache {
    14  	return lruCache{
    15  		values:   make(map[interface{}]*list.Element),
    16  		lruList:  list.New(),
    17  		capacity: capacity,
    18  	}
    19  }
    20  
    21  func (c *lruCache) clear() {
    22  	c.values = make(map[interface{}]*list.Element)
    23  	c.lruList.Init()
    24  }
    25  
    26  // Stores a value in the cache, returning true (and marking it as recently used) if it was
    27  // already there, or false if it was newly added.
    28  func (c *lruCache) add(value interface{}) bool {
    29  	if c.capacity == 0 {
    30  		return false
    31  	}
    32  	if e, ok := c.values[value]; ok {
    33  		c.lruList.MoveToFront(e)
    34  		return true
    35  	}
    36  	for len(c.values) >= c.capacity {
    37  		oldest := c.lruList.Back()
    38  		delete(c.values, oldest.Value)
    39  		c.lruList.Remove(oldest)
    40  	}
    41  	e := c.lruList.PushFront(value)
    42  	c.values[value] = e
    43  	return false
    44  }
    45
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