update Piwik to version 2.16 (fixes #91)

www/analytics/core/Tracker/TableLogAction/Cache.php

@@ -0,0 +1,160 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ *
+ */
+
+namespace Piwik\Tracker\TableLogAction;
+
+use Piwik\Common;
+use Piwik\Config;
+use Psr\Log\LoggerInterface;
+
+class Cache
+{
+    /**
+     * @var bool
+     */
+    public $isEnabled;
+
+    /**
+     * @var int cache lifetime in seconds
+     */
+    protected $lifetime;
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @var \Piwik\Cache\Lazy
+     */
+    private $cache;
+
+    public function __construct(LoggerInterface $logger, Config $config, \Piwik\Cache\Lazy $cache)
+    {
+        $this->isEnabled = (bool)$config->General['enable_segments_subquery_cache'];
+        $this->limitActionIds = $config->General['segments_subquery_cache_limit'];
+        $this->lifetime = $config->General['segments_subquery_cache_ttl'];
+        $this->logger = $logger;
+        $this->cache = $cache;
+    }
+
+    /**
+     * @param $valueToMatch
+     * @param $sql
+     * @return array|null
+     * @throws \Exception
+     */
+    public function getIdActionFromSegment($valueToMatch, $sql)
+    {
+        if (!$this->isEnabled) {
+            return array(
+                // mark that the returned value is an sql-expression instead of a literal value
+                'SQL' => $sql,
+                'bind' => $valueToMatch,
+            );
+        }
+
+        $ids = self::getIdsFromCache($valueToMatch, $sql);
+
+        if(is_null($ids)) {
+            // Too Big To Cache, issue SQL as subquery instead
+            return array(
+                'SQL' => $sql,
+                'bind' => $valueToMatch,
+            );
+        }
+
+        if(count($ids) == 0) {
+            return null;
+        }
+
+
+        $sql = Common::getSqlStringFieldsArray($ids);
+        $bind = $ids;
+
+        return array(
+            // mark that the returned value is an sql-expression instead of a literal value
+            'SQL'  => $sql,
+            'bind' => $bind,
+        );
+    }
+
+
+    /**
+     * @param $valueToMatch
+     * @param $sql
+     * @return array of IDs, or null if the returnset is too big to cache
+     */
+    private function getIdsFromCache($valueToMatch, $sql)
+    {
+        $cacheKey = $this->getCacheKey($valueToMatch, $sql);
+
+        if ($this->cache->contains($cacheKey) === true) { // TODO: hits
+            $this->logger->debug("Segment subquery cache HIT (for '$valueToMatch' and SQL '$sql)");
+            return $this->cache->fetch($cacheKey);
+        }
+
+        $ids = $this->fetchActionIdsFromDb($valueToMatch, $sql);
+
+        if($this->isTooBigToCache($ids)) {
+            $this->logger->debug("Segment subquery cache SKIPPED SAVE (too many IDs returned by subquery: %s ids)'", array(count($ids)));
+            $this->cache->save($cacheKey, $ids = null, $this->lifetime);
+            return null;
+        }
+
+        $this->cache->save($cacheKey, $ids, $this->lifetime);
+        $this->logger->debug("Segment subquery cache SAVE (for '$valueToMatch' and SQL '$sql')'");
+
+        return $ids;
+    }
+
+    /**
+     * @param $valueToMatch
+     * @param $sql
+     * @return string
+     * @throws
+     */
+    private function getCacheKey($valueToMatch, $sql)
+    {
+        if(is_array($valueToMatch)) {
+            throw new \Exception("value to match is an array: this is not expected");
+        }
+
+        $uniqueKey = md5($sql . $valueToMatch);
+        $cacheKey = 'TableLogAction.getIdActionFromSegment.' . $uniqueKey;
+        return $cacheKey;
+    }
+
+    /**
+     * @param $valueToMatch
+     * @param $sql
+     * @return array|null
+     * @throws \Exception
+     */
+    private function fetchActionIdsFromDb($valueToMatch, $sql)
+    {
+        $idActions = \Piwik\Db::fetchAll($sql, $valueToMatch);
+
+        $ids = array();
+        foreach ($idActions as $idAction) {
+            $ids[] = $idAction['idaction'];
+        }
+
+        return $ids;
+    }
+
+    /**
+     * @param $ids
+     * @return bool
+     */
+    private function isTooBigToCache($ids)
+    {
+        return count($ids) > $this->limitActionIds;
+    }
+}