+ [refac] add method to get memory usage.

lib/cache/cache.class.php

@@ -889,4 +889,16 @@ class cache
     {
         $this->cache->clear();
     }
+
+    /**
+     * 获取内存使用情况。
+     * Get memory usage.
+     *
+     * @param  string $type
+     * @return string
+     */
+    public function memory(string $type)
+    {
+        return $this->cache->memory($type);
+    }
 }

lib/cache/driver/ApcuDriver.php

@@ -81,4 +81,22 @@ class ApcuDriver implements CacheInterface
     {
         return (bool) apcu_exists($key);
     }
+
+    /**
+     * 获取内存使用情况。
+     * Get memory usage.
+     *
+     * @param  string $type
+     * @return string
+     */
+    public function memory($type)
+    {
+        $info = apcu_sma_info(true);
+
+        if($type == 'total') return \helper::formatKB($info['seg_size']);
+        if($type == 'free')  return \helper::formatKB($info['avail_mem']);
+        if($type == 'used')  return \helper::formatKB($info['seg_size'] - $info['avail_mem']);
+        if($type == 'rate')  return round(($info['seg_size'] - $info['avail_mem']) / $info['seg_size'] * 100, 2);
+        return '';
+    }
 }

lib/cache/driver/RedisDriver.php

@@ -230,4 +230,22 @@ class RedisDriver implements CacheInterface
     {
         return (bool) $this->redis->exists($key);
     }
+
+    /**
+     * 获取内存使用情况。
+     * Get memory usage.
+     *
+     * @param  string $type
+     * @return string
+     */
+    public function memory($type)
+    {
+        $info = $this->redis->info();
+
+        if($type == 'total') return $info['total_system_memory_human'];
+        if($type == 'free')  return \helper::formatKB($info['total_system_memory'] - $info['used_memory']);
+        if($type == 'used')  return $info['used_memory_human'];
+        if($type == 'rate')  return round(($info['used_memory'] / $info['total_system_memory']) * 100, 2);
+        return '';
+    }
 }