Added shared memory session cache + instant-sync for sessions in cache.

lib/defines.h

@@ -104,6 +104,9 @@ static const char * DBG_LVL_LIST[] = {"NONE", "FAIL", "ERROR", "WARN", "INFO", "
 #define SEM_CONF "/MstConfLock"
 #define SHM_CONF "MstConf"
 #define NAME_BUFFER_SIZE 200    //char buffer size for snprintf'ing shm filenames
+#define SHM_SESSIONS "/MstSess"
+#define SHM_SESSIONS_ITEM 165 //4 byte crc, 100b streamname, 20b connector, 40b host, 1b sync
+#define SHM_SESSIONS_SIZE 5248000 //5MiB = almost 32k sessions
 
 #define SHM_STREAM_ENCRYPT "MstCRYP%s" //%s stream name
 

src/controller/controller_statistics.cpp

@@ -212,9 +212,11 @@ void Controller::sessions_shutdown(const std::string & streamname, const std::st
 void Controller::SharedMemStats(void * config){
   DEBUG_MSG(DLVL_HIGH, "Starting stats thread");
   IPC::sharedServer statServer(SHM_STATISTICS, STAT_EX_SIZE, true);
+  IPC::sharedPage shmSessions(SHM_SESSIONS, SHM_SESSIONS_SIZE, true);
   statPointer = &statServer;
   std::set<std::string> inactiveStreams;
   while(((Util::Config*)config)->is_active){
+    uint32_t shmOffset = 0;
     {
       tthread::lock_guard<tthread::mutex> guard(Controller::configMutex);
       tthread::lock_guard<tthread::mutex> guard2(statsMutex);
@@ -228,6 +230,16 @@ void Controller::SharedMemStats(void * config){
           it->second.wipeOld(cutOffPoint);
           if (!it->second.hasData()){
             mustWipe.push_back(it->first);
+          }else{
+            //store an entry in the shmSessions page, if it fits
+            if (shmSessions.mapped && it->second.sync > 2 && shmOffset + SHM_SESSIONS_ITEM < SHM_SESSIONS_SIZE){
+              *((uint32_t*)(shmSessions.mapped+shmOffset)) = it->first.crc;
+              strncpy(shmSessions.mapped+shmOffset+4, it->first.streamName.c_str(), 100);
+              strncpy(shmSessions.mapped+shmOffset+104, it->first.connector.c_str(), 20);
+              strncpy(shmSessions.mapped+shmOffset+124, it->first.host.c_str(), 40);
+              shmSessions.mapped[shmOffset+164] = it->second.sync;
+              shmOffset += SHM_SESSIONS_ITEM;
+            }
           }
         }
         while (mustWipe.size()){
@@ -235,6 +247,10 @@ void Controller::SharedMemStats(void * config){
           mustWipe.pop_front();
         }
       }
+      if (shmSessions.mapped){
+        //set a final shmSessions entry to all zeroes
+        memset(shmSessions.mapped+shmOffset, 0, SHM_SESSIONS_ITEM);
+      }
       if (activeStreams.size()){
         for (std::map<std::string, unsigned int>::iterator it = activeStreams.begin(); it != activeStreams.end(); ++it){
           if (++it->second > STATS_DELAY){
@@ -256,6 +272,7 @@ void Controller::SharedMemStats(void * config){
   HIGH_MSG("Stopping stats thread");
   if (Controller::restarting){
     statServer.abandon();
+    shmSessions.master = false;
   }else{/*LTS-START*/
     if (Controller::killOnExit){
       DEBUG_MSG(DLVL_WARN, "Killing all connected clients to force full shutdown");

src/output/output.cpp

@@ -172,8 +172,51 @@ namespace Mist {
     if (tmpEx.getSync() == 2 || force){
       if (getStatsName() == capa["name"].asStringRef() && Triggers::shouldTrigger("USER_NEW", streamName)){
         //sync byte 0 = no sync yet, wait for sync from controller...
+        char initialSync = 0;
+        //attempt to load sync status from session cache in shm
+        {
+          IPC::sharedPage shmSessions(SHM_SESSIONS, SHM_SESSIONS_SIZE, false, false);
+          if (shmSessions.mapped){
+            char shmEmpty[SHM_SESSIONS_ITEM];
+            memset(shmEmpty, 0, SHM_SESSIONS_ITEM);
+            std::string host = tmpEx.host();
+            if (host.substr(0, 12) == std::string("\000\000\000\000\000\000\000\000\000\000\377\377", 12)){
+              char tmpstr[16];
+              snprintf(tmpstr, 16, "%hhu.%hhu.%hhu.%hhu", host[12], host[13], host[14], host[15]);
+              host = tmpstr;
+            }else{
+              char tmpstr[40];
+              snprintf(tmpstr, 40, "%0.2x%0.2x:%0.2x%0.2x:%0.2x%0.2x:%0.2x%0.2x:%0.2x%0.2x:%0.2x%0.2x:%0.2x%0.2x:%0.2x%0.2x", host[0], host[1], host[2], host[3], host[4], host[5], host[6], host[7], host[8], host[9], host[10], host[11], host[12], host[13], host[14], host[15]);
+              host = tmpstr;
+            }
+            uint32_t shmOffset = 0;
+            const std::string & cName = capa["name"].asStringRef();
+            while (shmOffset + SHM_SESSIONS_ITEM < SHM_SESSIONS_SIZE){
+              //compare crc
+              if (*((uint32_t*)(shmSessions.mapped+shmOffset)) == tmpEx.crc()){
+                //compare stream name
+                if (strncmp(shmSessions.mapped+shmOffset+4, streamName.c_str(), 100) == 0){
+                  //compare connector
+                  if (strncmp(shmSessions.mapped+shmOffset+104, cName.c_str(), 20) == 0){
+                    //compare host
+                    if (strncmp(shmSessions.mapped+shmOffset+124, host.c_str(), 40) == 0){
+                      initialSync = shmSessions.mapped[shmOffset+164];
+                      INFO_MSG("Instant-sync from session cache to %u", (unsigned int)initialSync);
+                      break;
+                    }
+                  }
+                }
+              }
+              //stop if we reached the end
+              if (memcmp(shmSessions.mapped+shmOffset, shmEmpty, SHM_SESSIONS_ITEM) == 0){
+                break;
+              }
+              shmOffset += SHM_SESSIONS_ITEM;
+            }
+          }
+        }
         unsigned int i = 0;
-        tmpEx.setSync(0);
+        tmpEx.setSync(initialSync);
         //wait max 10 seconds for sync
         while ((!tmpEx.getSync() || tmpEx.getSync() == 2) && i++ < 100){
           Util::wait(100);