From e574af7e6e039244f10080936e21c70d33bafb03 Mon Sep 17 00:00:00 2001
From: Johan Wikman <johan.wikman@mariadb.com>
Date: Thu, 8 Dec 2016 23:48:13 +0200
Subject: [PATCH] Cache: Derived CacheFilterSession from
 maxscale::FilterSession

---
 server/modules/filter/cache/cachefilter.cc    |  8 ++++--
 .../filter/cache/cachefiltersession.cc        | 24 +++++-------------
 .../filter/cache/cachefiltersession.hh        | 25 +++----------------
 3 files changed, 15 insertions(+), 42 deletions(-)

diff --git a/server/modules/filter/cache/cachefilter.cc b/server/modules/filter/cache/cachefilter.cc
index 5f8be48bb..b55020f1e 100644
--- a/server/modules/filter/cache/cachefilter.cc
+++ b/server/modules/filter/cache/cachefilter.cc
@@ -272,7 +272,9 @@ static void setDownstream(FILTER* pInstance, void* pSessionData, DOWNSTREAM* pDo
 {
     CacheFilterSession* pCacheFilterSession = static_cast<CacheFilterSession*>(pSessionData);
 
-    MXS_EXCEPTION_GUARD(pCacheFilterSession->setDownstream(pDownstream));
+    CacheFilterSession::Downstream down(*pDownstream);
+
+    MXS_EXCEPTION_GUARD(pCacheFilterSession->setDownstream(down));
 }
 
 /**
@@ -286,7 +288,9 @@ static void setUpstream(FILTER* pInstance, void* pSessionData, UPSTREAM* pUpstre
 {
     CacheFilterSession* pCacheFilterSession = static_cast<CacheFilterSession*>(pSessionData);
 
-    MXS_EXCEPTION_GUARD(pCacheFilterSession->setUpstream(pUpstream));
+    CacheFilterSession::Upstream up(*pUpstream);
+
+    MXS_EXCEPTION_GUARD(pCacheFilterSession->setUpstream(up));
 }
 
 /**
diff --git a/server/modules/filter/cache/cachefiltersession.cc b/server/modules/filter/cache/cachefiltersession.cc
index be058ef11..e8dd53229 100644
--- a/server/modules/filter/cache/cachefiltersession.cc
+++ b/server/modules/filter/cache/cachefiltersession.cc
@@ -19,16 +19,14 @@
 #include <maxscale/mysql_utils.h>
 #include "storage.h"
 
-CacheFilterSession::CacheFilterSession(Cache* pCache, SESSION* pSession, char* zDefaultDb)
-    : m_state(CACHE_EXPECTING_NOTHING)
+CacheFilterSession::CacheFilterSession(SESSION* pSession, Cache* pCache, char* zDefaultDb)
+    : maxscale::FilterSession(pSession)
+    , m_state(CACHE_EXPECTING_NOTHING)
     , m_pCache(pCache)
-    , m_pSession(pSession)
     , m_zDefaultDb(zDefaultDb)
     , m_zUseDb(NULL)
     , m_refreshing(false)
 {
-    memset(&m_down, 0, sizeof(m_down));
-    memset(&m_up, 0, sizeof(m_up));
     memset(m_key.data, 0, CACHE_KEY_MAXLEN);
 
     reset_response_state();
@@ -58,7 +56,7 @@ CacheFilterSession* CacheFilterSession::Create(Cache* pCache, SESSION* pSession)
 
     if ((pMysqlSession->db[0] == 0) || zDefaultDb)
     {
-        pCacheFilterSession = new (std::nothrow) CacheFilterSession(pCache, pSession, zDefaultDb);
+        pCacheFilterSession = new (std::nothrow) CacheFilterSession(pSession, pCache, zDefaultDb);
 
         if (!pCacheFilterSession)
         {
@@ -73,16 +71,6 @@ void CacheFilterSession::close()
 {
 }
 
-void CacheFilterSession::setDownstream(DOWNSTREAM* pDown)
-{
-    m_down = *pDown;
-}
-
-void CacheFilterSession::setUpstream(UPSTREAM* pUp)
-{
-    m_up = *pUp;
-}
-
 int CacheFilterSession::routeQuery(GWBUF* pPacket)
 {
     uint8_t* pData = static_cast<uint8_t*>(GWBUF_DATA(pPacket));
@@ -231,7 +219,7 @@ int CacheFilterSession::routeQuery(GWBUF* pPacket)
 
     if (fetch_from_server)
     {
-        rv = m_down.routeQuery(m_down.instance, m_down.session, pPacket);
+        rv = m_down.routeQuery(pPacket);
     }
 
     return rv;
@@ -584,7 +572,7 @@ int CacheFilterSession::send_upstream()
 {
     ss_dassert(m_res.pData != NULL);
 
-    int rv = m_up.clientReply(m_up.instance, m_up.session, m_res.pData);
+    int rv = m_up.clientReply(m_res.pData);
     m_res.pData = NULL;
 
     return rv;
diff --git a/server/modules/filter/cache/cachefiltersession.hh b/server/modules/filter/cache/cachefiltersession.hh
index b9385f877..3c874a1f2 100644
--- a/server/modules/filter/cache/cachefiltersession.hh
+++ b/server/modules/filter/cache/cachefiltersession.hh
@@ -14,14 +14,12 @@
 
 #include <maxscale/cdefs.h>
 #include <maxscale/buffer.h>
-#include <maxscale/filter.h>
+#include <maxscale/filter.hh>
 #include "cache.h"
 #include "cachefilter.h"
 #include "cache_storage_api.h"
 
-class Cache;
-
-class CacheFilterSession
+class CacheFilterSession : public maxscale::FilterSession
 {
 public:
     enum cache_session_state_t
@@ -67,20 +65,6 @@ public:
      */
     void close();
 
-    /**
-     * Set the downstream component for this session.
-     *
-     * @param pDown  The downstream filter or router
-     */
-    void setDownstream(DOWNSTREAM* pDownstream);
-
-    /**
-     * Set the upstream component for this session.
-     *
-     * @param pUp  The upstream filter or router
-     */
-    void setUpstream(UPSTREAM* pUpstream);
-
     /**
      * A request on its way to a backend is delivered to this function.
      *
@@ -122,7 +106,7 @@ private:
     void store_result();
 
 private:
-    CacheFilterSession(Cache* pCache, SESSION* pSession, char* zDefaultDb);
+    CacheFilterSession(SESSION* pSession, Cache* pCache, char* zDefaultDb);
 
     CacheFilterSession(const CacheFilterSession&);
     CacheFilterSession& operator = (const CacheFilterSession&);
@@ -130,9 +114,6 @@ private:
 private:
     cache_session_state_t m_state;       /**< What state is the session in, what data is expected. */
     Cache*                m_pCache;      /**< The cache instance the session is associated with. */
-    SESSION*              m_pSession;    /**< The session this data is associated with. */
-    DOWNSTREAM            m_down;        /**< The previous filter or equivalent. */
-    UPSTREAM              m_up;          /**< The next filter or equivalent. */
     CACHE_RESPONSE_STATE  m_res;         /**< The response state. */
     CACHE_KEY             m_key;         /**< Key storage. */
     char*                 m_zDefaultDb;  /**< The default database. */