1 files changed, 128 insertions, 0 deletions
diff --git a/vendor/jonahgeorge/jaeger-client-php/src/Jaeger/Util/RateLimiter.php b/vendor/jonahgeorge/jaeger-client-php/src/Jaeger/Util/RateLimiter.php
new file mode 100644
index 000000000..d767ad40f
--- /dev/null
+++ b/vendor/jonahgeorge/jaeger-client-php/src/Jaeger/Util/RateLimiter.php
@@ -0,0 +1,128 @@
+<?php
+
+namespace Jaeger\Util;
+
+use Psr\Cache\CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface;
+
+class RateLimiter
+{
+    /**
+     * @var CacheItemPoolInterface
+     */
+    private $cache;
+
+    /**
+     * @var CacheItemInterface
+     */
+    private $balance;
+
+    /**
+     * @var CacheItemInterface
+     */
+    private $lastTick;
+
+    /**
+     * @var float
+     */
+    private $creditsPerNanosecond = 0;
+
+    /**
+     * @var float
+     */
+    private $maxBalance = 0;
+
+    /**
+     * RateLimiter constructor.
+     *
+     * @param CacheItemPoolInterface $cache
+     * @param string $currentBalanceKey key of current balance value in $cache
+     * @param string $lastTickKey key of last tick value in $cache
+     * @throws \Psr\Cache\InvalidArgumentException
+     */
+    public function __construct(
+        CacheItemPoolInterface $cache,
+        string $currentBalanceKey,
+        string $lastTickKey
+    ) {
+        $this->cache = $cache;
+        $this->balance = $this->cache->getItem($currentBalanceKey);
+        $this->lastTick = $this->cache->getItem($lastTickKey);
+    }
+
+    /**
+     * @param $itemCost
+     * @return bool
+     */
+    public function checkCredit($itemCost)
+    {
+        if (!$this->creditsPerNanosecond) {
+            return false;
+        }
+
+        list($lastTick, $balance) = $this->getState();
+
+        if (!$lastTick) {
+            $this->saveState(hrtime(true), 0);
+            return true;
+        }
+
+        $currentTick = hrtime(true);
+        $elapsedTime = $currentTick - $lastTick;
+        $balance += $elapsedTime * $this->creditsPerNanosecond;
+        if ($balance > $this->maxBalance) {
+            $balance = $this->maxBalance;
+        }
+
+        $result = false;
+        if ($balance >= $itemCost) {
+            $balance -= $itemCost;
+            $result = true;
+        }
+
+        $this->saveState($currentTick, $balance);
+
+        return $result;
+    }
+
+
+    /**
+     * Initializes limiter costs and boundaries
+     *
+     * @param float $creditsPerNanosecond
+     * @param float $maxBalance
+     */
+    public function initialize(float $creditsPerNanosecond, float $maxBalance)
+    {
+        $this->creditsPerNanosecond = $creditsPerNanosecond;
+        $this->maxBalance = $maxBalance;
+    }
+
+    /**
+     * Method loads last tick and current balance from cache
+     *
+     * @return array [$lastTick, $balance]
+     */
+    private function getState() : array
+    {
+        return [
+            $this->lastTick->get(),
+            $this->balance->get()
+        ];
+    }
+
+    /**
+     * Method saves last tick and current balance into cache
+     *
+     * @param integer $lastTick
+     * @param float $balance
+     */
+    private function saveState($lastTick, $balance)
+    {
+        $this->lastTick->set($lastTick);
+        $this->balance->set($balance);
+        $this->cache->saveDeferred($this->lastTick);
+        $this->cache->saveDeferred($this->balance);
+        $this->cache->commit();
+    }
+}