Added dynamic choose of sources for chunk crc requests. Fixes the bug that would let

a transfer not finish if the original surce for a crc is not here anymore.

If you have a unfinished transfer do a force-check after restart to get back chunks that 
where still on verificaiton stage.



git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@5315 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/ft/ftchunkmap.cc

@@ -211,25 +211,13 @@ void ChunkMap::updateTotalDownloaded()
 	}
 }
 
-void ChunkMap::getChunksToCheck(std::vector<std::pair<uint32_t,std::list<std::string> > >& chunks_crc_to_ask)
+void ChunkMap::getChunksToCheck(std::vector<uint32_t>& chunks_crc_to_ask)
 {
 	chunks_crc_to_ask.clear() ;
 
 	for(uint32_t i=0;i<_chunks_checking_queue.size();)
 	{
-		std::list<std::string> peers ;
-
-		for(std::map<std::string,SourceChunksInfo>::const_iterator it2(_peers_chunks_availability.begin());it2!=_peers_chunks_availability.end();++it2)
-			if(it2->second.cmap[_chunks_checking_queue[i]])
-				peers.push_back(it2->first) ;
-
-		if(peers.empty())	// no peers => can't ask!
-		{
-			++i ;
-			continue ;
-		}
-
-		chunks_crc_to_ask.push_back(std::pair<uint32_t,std::list<std::string> >(_chunks_checking_queue[i],peers)) ;
+		chunks_crc_to_ask.push_back(_chunks_checking_queue[i]) ;
 
 		// remove that chunk from the queue
 
@@ -528,6 +516,15 @@ SourceChunksInfo *ChunkMap::getSourceChunksInfo(const std::string& peer_id)
 	return &(it->second) ;
 }
 
+void ChunkMap::getSourcesList(uint32_t chunk_number,std::vector<std::string>& sources) 
+{
+	sources.clear() ;
+
+	for(std::map<std::string,SourceChunksInfo>::const_iterator it(_peers_chunks_availability.begin());it!=_peers_chunks_availability.end();++it)
+		if(it->second.cmap[chunk_number])
+			sources.push_back(it->first) ;
+}
+
 uint32_t ChunkMap::getAvailableChunk(const std::string& peer_id,bool& map_is_too_old) 
 {
 	// Quite simple strategy: Check for 1st availabe chunk for this peer starting from the given start location.

libretroshare/src/ft/ftchunkmap.h

@@ -185,7 +185,10 @@ class ChunkMap
 		void setChunkCheckingResult(uint32_t chunk_number, bool succeed) ;
 
 		/// returns the current list of chunks to ask for a CRC, and a proposed source for each
-		void getChunksToCheck(std::vector<std::pair<unsigned int, std::list<std::string> > >& chunks_to_ask) ;
+		void getChunksToCheck(std::vector<uint32_t>& chunks_to_ask) ;
+
+		/// Get all available sources for this chunk
+		void getSourcesList(uint32_t chunk_number,std::vector<std::string>& sources) ;
 
 		/// sets all chunks to checking state
 		void forceCheck() ;

libretroshare/src/ft/ftdatamultiplex.cc

@@ -499,7 +499,7 @@ bool ftDataMultiplex::recvSingleChunkCrc(const std::string& peerId, const std::s
 	// remove this chunk from the request list as well.
 	
 	Sha1CacheEntry& sha1cache(_cached_sha1maps[hash]) ;
-	std::map<uint32_t,ChunkCheckSumSourceList>::iterator it2(sha1cache._to_ask.find(chunk_number)) ;
+	std::map<uint32_t,std::pair<time_t,ChunkCheckSumSourceList> >::iterator it2(sha1cache._to_ask.find(chunk_number)) ;
 
 	if(it2 != sha1cache._to_ask.end())
 		sha1cache._to_ask.erase(it2) ;
@@ -1146,7 +1146,7 @@ bool ftDataMultiplex::sendCRC32MapRequest(const std::string& peer_id,const std::
 {
 	return mDataSend->sendCRC32MapRequest(peer_id,hash);
 }
-bool ftDataMultiplex::sendSingleChunkCRCRequests(const std::string& hash, const std::vector<std::pair<uint32_t,std::list<std::string> > >& to_ask)
+bool ftDataMultiplex::sendSingleChunkCRCRequests(const std::string& hash, const std::vector<uint32_t>& to_ask)
 {
 	RsStackMutex stack(dataMtx); /******* LOCK MUTEX ******/
 
@@ -1156,10 +1156,8 @@ bool ftDataMultiplex::sendSingleChunkCRCRequests(const std::string& hash, const
 
 	for(uint32_t i=0;i<to_ask.size();++i)
 	{
-		ChunkCheckSumSourceList& list(ce._to_ask[to_ask[i].first]) ;
-
-		for(std::list<std::string>::const_iterator it(to_ask[i].second.begin());it!=to_ask[i].second.end();++it)
-			list[*it] = 0 ;
+		std::pair<time_t,ChunkCheckSumSourceList>& list(ce._to_ask[to_ask[i]]) ;
+		list.first = 0 ; // set last request time to 0
 	}
 	return true ;
 }
@@ -1171,22 +1169,87 @@ void ftDataMultiplex::handlePendingCrcRequests()
 	time_t now = time(NULL) ;
 	uint32_t n=0 ;
 
+	// Go through the list of currently handled hashes. For each of them,
+	// look for pending chunk crc requests. 
+	// 	- if the last request is too old, re-ask:
+	// 		- ask the file creator about the possible sources for this chunk => returns a list of active sources
+	//			- among active sources, pick the one that has the smallest request time stamp, in the request list.
+	//
+	// With this, only active sources are querried.
+	//
+
 	for(std::map<std::string,Sha1CacheEntry>::iterator it(_cached_sha1maps.begin());it!=_cached_sha1maps.end();++it)
-		for(std::map<uint32_t,ChunkCheckSumSourceList>::iterator it2(it->second._to_ask.begin());it2!=it->second._to_ask.end();++it2)
-			for(std::map<std::string,time_t>::iterator it3(it2->second.begin());it3!=it2->second.end();++it3) 
-				if(it3->second + MAX_CHECKING_CHUNK_WAIT_DELAY < now) // do nothing, otherwise, ask again
+		for(std::map<uint32_t,std::pair<time_t,ChunkCheckSumSourceList> >::iterator it2(it->second._to_ask.begin());it2!=it->second._to_ask.end();++it2)
+			if(it2->second.first + MAX_CHECKING_CHUNK_WAIT_DELAY < now)	// is the last request old enough?
+			{
+#ifdef MPLEX_DEBUG
+				std::cerr << "ftDataMultiplex::handlePendingCrcRequests():  Requesting sources for chunk " << it2->first << ", hash " << it->first << std::endl;
+#endif
+				// 0 - ask which sources can be used for this chunk
+				//
+				std::map<std::string,ftClient>::const_iterator it4(mClients.find(it->first)) ;
+
+				if(it4 == mClients.end())
+					continue ;
+
+				std::vector<std::string> sources ;
+				it4->second.mCreator->getSourcesList(it2->first,sources) ;
+
+				// 1 - go through all sources. Take the oldest one.
+				//
+
+				std::string best_source ;
+				time_t oldest_timestamp = now ;
+
+				for(uint32_t i=0;i<sources.size();++i)
 				{
 #ifdef MPLEX_DEBUG
-					std::cerr << "ftDataMultiplex::handlePendingCrcRequests(): Asking crc of chunk " << it2->first << " to peer " << it3->first << " for hash " << it->first << std::endl;
+					std::cerr << "ftDataMultiplex::handlePendingCrcRequests():    Examining source " << sources[i] << std::endl;
 #endif
-					mDataSend->sendSingleChunkCRCRequest(it3->first,it->first,it2->first);
-					it3->second = now ;
+					std::map<std::string,time_t>::const_iterator it3(it2->second.second.find(sources[i])) ;
+
+					if(it3 == it2->second.second.end()) // source not found. So this one is surely the oldest one to have been requested.
+					{
+#ifdef MPLEX_DEBUG
+						std::cerr << "ftDataMultiplex::handlePendingCrcRequests():    not found! So using it directly." << std::endl;
+#endif
+						best_source = sources[i] ;
+						break ;
+					}
+					else if(it3->second <= oldest_timestamp) // do nothing, otherwise, ask again
+					{
+#ifdef MPLEX_DEBUG
+						std::cerr << "ftDataMultiplex::handlePendingCrcRequests():    not found! So using it directly." << std::endl;
+#endif
+						best_source = sources[i] ;
+						oldest_timestamp = it3->second ;
+					}
+#ifdef MPLEX_DEBUG
+					else
+						std::cerr << "ftDataMultiplex::handlePendingCrcRequests():    Source too recently used! So using it directly." << std::endl;
+#endif
+				}
+				if(best_source != "")
+				{
+#ifdef MPLEX_DEBUG
+					std::cerr << "ftDataMultiplex::handlePendingCrcRequests(): Asking crc of chunk " << it2->first << " to peer " << best_source << " for hash " << it->first << std::endl;
+#endif
+					// Use the source to ask the CRC.
+					//
+					// 	sendSingleChunkCRCRequest(peer_id, hash, chunk_id)
+					//
+					mDataSend->sendSingleChunkCRCRequest(best_source,it->first,it2->first);
+					it2->second.second[best_source] = now ;
+					it2->second.first = now ;
 
 					if(++n > MAX_SIMULTANEOUS_CRC_REQUESTS)
 						return ;
-
-					break ;	// go to next chunk. Don't ask the same chunk to multiple sources.
 				}
+#ifdef MPLEX_DEBUG
+				else
+					std::cerr << "ftDataMultiplex::handlePendingCrcRequests(): no source for chunk " << it2->first << std::endl;
+#endif
+			}
 }
 
 void ftDataMultiplex::deleteUnusedServers()

libretroshare/src/ft/ftdatamultiplex.h

@@ -86,7 +86,7 @@ class Sha1CacheEntry
 		Sha1Map _map ; 												// Map of available sha1 sums for every chunk.
 		time_t last_activity ;										// This is used for removing unused entries.
 		std::vector<uint32_t> _received ;						// received chunk ids. To bedispatched.
-		std::map<uint32_t,ChunkCheckSumSourceList> _to_ask ;		// Chunks to ask to sources.
+		std::map<uint32_t,std::pair<time_t,ChunkCheckSumSourceList> > _to_ask ;		// Chunks to ask to sources.
 };
 	
 class ftDataMultiplex: public ftDataRecv, public RsQueueThread
@@ -128,7 +128,7 @@ class ftDataMultiplex: public ftDataRecv, public RsQueueThread
 		bool computeAndSendCRC32Map(const std::string& peerId, const std::string& hash) ;
 
 		/* called from a separate thread */
-		bool sendSingleChunkCRCRequests(const std::string& hash, const std::vector<std::pair<uint32_t, std::list<std::string > > >& to_ask) ;
+		bool sendSingleChunkCRCRequests(const std::string& hash, const std::vector<uint32_t>& to_ask) ;
 
 		bool dispatchReceivedChunkCheckSum() ;
 

libretroshare/src/ft/ftfilecreator.cc

@@ -616,7 +616,14 @@ void ftFileCreator::forceCheck()
 	chunkMap.forceCheck(); 
 }
 
-void ftFileCreator::getChunksToCheck(std::vector<std::pair<uint32_t,std::list<std::string> > >& chunks_to_ask)
+void ftFileCreator::getSourcesList(uint32_t chunk_num,std::vector<std::string>& sources)
+{
+	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
+
+	chunkMap.getSourcesList(chunk_num,sources) ;
+}
+
+void ftFileCreator::getChunksToCheck(std::vector<uint32_t>& chunks_to_ask)
 {
 	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
 	

libretroshare/src/ft/ftfilecreator.h

@@ -86,7 +86,7 @@ class ftFileCreator: public ftFileProvider
 		// Looks into the chunkmap for downloaded chunks that have not yet been certified.
 		// For each of them, returns the chunk number and a source peer to ask the CRC to.
 		//
-		void getChunksToCheck(std::vector<std::pair<uint32_t,std::list<std::string> > >& chunks_to_ask) ;
+		void getChunksToCheck(std::vector<uint32_t>& chunks_to_ask) ;
 
 		/* 
 		 * creation functions for FileCreator 
@@ -107,6 +107,10 @@ class ftFileCreator: public ftFileProvider
 		// removes the designated file source from the chunkmap.
 		void removeFileSource(const std::string& peer_id) ;
 
+		// Get all available sources for this chunk
+		//
+		void getSourcesList(uint32_t chunk_number,std::vector<std::string>& sources) ;
+
 		// Returns resets the time stamp of the last data receive.
 		time_t lastRecvTimeStamp() ;
 		void resetRecvTimeStamp() ;

libretroshare/src/ft/fttransfermodule.cc

@@ -431,7 +431,7 @@ bool ftTransferModule::queryInactive()
 	else
 	{
 		// request for CRCs to ask
-		std::vector<std::pair<uint32_t,std::list<std::string> > > chunks_to_ask ;
+		std::vector<uint32_t> chunks_to_ask ;
 
 #ifdef FT_DEBUG
 		std::cerr << "ftTransferModule::queryInactive() : getting chunks to check." << std::endl;