covered situation in which cache entries are invalidated when messages expire

git-svn-id: http://svn.code.sf.net/p/retroshare/code/branches/v0.5-cacheopt@4459 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/services/p3distrib.cc

@@ -476,6 +476,54 @@ void p3GroupDistrib::updateCacheDocument()
 	return;
 }
 
+struct by_cacheid
+{
+	bool operator()(pugi::xml_node node) const
+	{
+		bool cachIdEqual = true;
+		cachIdEqual &= (node.child_value("subId") == subId);
+		cachIdEqual &= (node.child_value("pId") == peerId);
+		return cachIdEqual;
+	}
+
+	std::string peerId;
+	std::string subId;
+};
+
+void p3GroupDistrib::locked_removeCacheTableEntry(const pCacheId& pCid)
+{
+
+	// search through cache document for all entries with this cache id
+
+	pugi::xml_node_iterator nit = mCacheDoc.begin();
+	by_cacheid bCid;
+	bCid.peerId = pCid.first;
+
+	char subIdBuffer[6];
+	std::string subId;
+	sprintf(subIdBuffer, "%d", pCid.second);
+	subId = subIdBuffer;
+	bCid.subId = subId;
+
+	// for each grp, remove message nodes that match pCid
+	for(; nit != mCacheDoc.end(); nit++)
+	{
+		pugi::xml_node msgNode = nit->child("messages");
+
+		if(msgNode)
+		{
+			while(pugi::xml_node cNode= msgNode.find_child(bCid))
+			{
+				msgNode.remove_child(cNode);
+			}
+		}
+	}
+
+	locked_buildCacheTable();
+
+	return;
+}
+
 void p3GroupDistrib::locked_updateCacheTableGrp(const std::vector<grpNodePair>& grpNodes, bool historical)
 {
 
@@ -553,6 +601,7 @@ bool p3GroupDistrib::locked_historyCached(const std::string& grpId, bool& cached
 	std::map<std::string, nodeCache>::iterator cit;
 	if(mCacheTable.end() != (cit = mCacheTable.find(grpId)))
 	{
+
 		cached = cit->second.cached;
 		return true;
 	}
@@ -561,6 +610,8 @@ bool p3GroupDistrib::locked_historyCached(const std::string& grpId, bool& cached
 	return false;
 }
 
+
+
 bool p3GroupDistrib::locked_historyCached(const pCacheId& cId)
 {
 
@@ -588,6 +639,9 @@ bool p3GroupDistrib::locked_buildCacheTable(){
 		return false;
 	}
 
+	// clear cache table
+	mCacheTable.clear();
+
 	pugi::xml_node_iterator grpIt = mCacheDoc.begin(), msgIt;
 	pugi::xml_node messages_node;
 	std::map<std::string, std::set<pCacheId> > msgCacheMap;
@@ -769,7 +823,6 @@ void p3GroupDistrib::locked_getHistoryCacheData(const std::string& grpId, std::l
 			}
 			else
 				locked_getStoredCache(cDataTemp);
-
 				cDataSet.push_back(cDataTemp);
 		}
 	}
@@ -1869,6 +1922,8 @@ void 	p3GroupDistrib::locked_publishPendingMsgs()
 	newCache.cid.type = CacheSource::getCacheType();
 	newCache.cid.subid = locked_determineCacheSubId();
 
+	// remove old cache entry using this pid
+	locked_removeCacheTableEntry(pCacheId(newCache.pid, newCache.cid.subid));
 
 	/* create filename */
 	std::string path = CacheSource::getCacheDir();
@@ -1916,9 +1971,6 @@ void 	p3GroupDistrib::locked_publishPendingMsgs()
 		{
 			ok &= false;
 		}
-
-
-
 	}
 
 	/* Extract File Information from pqistore */

libretroshare/src/services/p3distrib.h

@@ -413,6 +413,15 @@ class p3GroupDistrib: public CacheSource, public CacheStore, public p3Config, pu
 		 */
 		bool locked_loadHistoryCacheFile();
 
+		/*!
+		 * this removes the given cache id and associated msgs nodes from
+		 * all grp nodes
+		 * cache table is updated to reflect document
+		 * this costly, and is here to be called once a year has been reached on
+		 * @param pCid the cache id to remove from cache document
+		 */
+		void locked_removeCacheTableEntry(const pCacheId& pCid);
+
 	private:
 
 		/* these lists are filled by the overloaded fns... then cleared by the thread */
@@ -667,6 +676,9 @@ class p3GroupDistrib: public CacheSource, public CacheStore, public p3Config, pu
 		void    locked_publishPendingMsgs();
 
 		/*!
+		 * This function is key to determining how long caches permeate
+		 * a distributed network, after mStorePeriod has elapsed for a message
+		 * it is over written since its cache subid is used for the cache file name
 		 * @return cache sub id
 		 */
 		uint16_t locked_determineCacheSubId();