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<?php |
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|
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namespace Dudlewebs\WPMCS\s3\Aws; |
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|
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/** |
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* Simple in-memory LRU cache that limits the number of cached entries. |
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* |
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* The LRU cache is implemented using PHP's ordered associative array. When |
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* accessing an element, the element is removed from the hash and re-added to |
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* ensure that recently used items are always at the end of the list while |
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* least recently used are at the beginning. When a value is added to the |
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* cache, if the number of cached items exceeds the allowed number, the first |
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* N number of items are removed from the array. |
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*/ |
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class LruArrayCache implements CacheInterface, \Countable |
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{ |
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/** @var int */ |
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private $maxItems; |
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/** @var array */ |
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private $items = array(); |
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/** |
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* @param int $maxItems Maximum number of allowed cache items. |
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*/ |
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public function __construct($maxItems = 1000) |
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{ |
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$this->maxItems = $maxItems; |
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} |
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public function get($key) |
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{ |
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if (!isset($this->items[$key])) { |
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return null; |
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} |
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$entry = $this->items[$key]; |
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// Ensure the item is not expired. |
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if (!$entry[1] || \time() < $entry[1]) { |
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// LRU: remove the item and push it to the end of the array. |
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unset($this->items[$key]); |
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$this->items[$key] = $entry; |
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return $entry[0]; |
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} |
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unset($this->items[$key]); |
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return null; |
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} |
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public function set($key, $value, $ttl = 0) |
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{ |
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// Only call time() if the TTL is not 0/false/null |
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$ttl = $ttl ? \time() + $ttl : 0; |
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$this->items[$key] = [$value, $ttl]; |
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// Determine if there are more items in the cache than allowed. |
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$diff = \count($this->items) - $this->maxItems; |
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// Clear out least recently used items. |
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if ($diff > 0) { |
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// Reset to the beginning of the array and begin unsetting. |
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\reset($this->items); |
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for ($i = 0; $i < $diff; $i++) { |
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unset($this->items[\key($this->items)]); |
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\next($this->items); |
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} |
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} |
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} |
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public function remove($key) |
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{ |
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unset($this->items[$key]); |
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} |
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/** |
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* @return int |
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*/ |
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#[\ReturnTypeWillChange] |
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public function count() |
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{ |
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return \count($this->items); |
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} |
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} |
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