[host] shutdown capture if there are no subscribers

Fixes #33

host/src/app.c

@@ -62,6 +62,14 @@ static const struct LGMPQueueConfig POINTER_QUEUE_CONFIG =
 
 #define MAX_POINTER_SIZE (sizeof(KVMFRCursor) + (128 * 128 * 4))
 
+enum AppState
+{
+  APP_STATE_RUNNING,
+  APP_STATE_IDLE,
+  APP_STATE_RESTART,
+  APP_STATE_SHUTDOWN
+};
+
 struct app
 {
   PLGMPHost     lgmp;
@@ -81,8 +89,7 @@ struct app
 
   CaptureInterface * iface;
 
-  bool       running;
-  bool       reinit;
+  enum AppState state;
   LGTimer  * lgmpTimer;
   LGThread * frameThread;
 };
@@ -95,7 +102,7 @@ static bool lgmpTimer(void * opaque)
   if ((status = lgmpHostProcess(app.lgmp)) != LGMP_OK)
   {
     DEBUG_ERROR("lgmpHostProcess Failed: %s", lgmpStatusString(status));
-    app.running = false;
+    app.state = APP_STATE_SHUTDOWN;
     return false;
   }
 
@@ -111,7 +118,7 @@ static int frameThread(void * opaque)
   CaptureFrame frame          = { 0 };
   const long   pageSize       = sysinfo_getPageSize();
 
-  while(app.running)
+  while(app.state == APP_STATE_RUNNING)
   {
     //wait until there is room in the queue
     if(lgmpHostQueuePending(app.frameQueue) == LGMP_Q_FRAME_LEN)
@@ -128,7 +135,7 @@ static int frameThread(void * opaque)
 
       case CAPTURE_RESULT_REINIT:
       {
-        app.reinit = true;
+        app.state = APP_STATE_RESTART;
         DEBUG_INFO("Frame thread reinit");
         return 0;
       }
@@ -205,7 +212,7 @@ static int frameThread(void * opaque)
 
 bool startThreads()
 {
-  app.running = true;
+  app.state = APP_STATE_RUNNING;
   if (!lgCreateThread("FrameThread", frameThread, NULL, &app.frameThread))
   {
     DEBUG_ERROR("Failed to create the frame thread");
@@ -219,8 +226,9 @@ bool stopThreads()
 {
   bool ok = true;
 
-  app.running = false;
   app.iface->stop();
+  if (app.state != APP_STATE_SHUTDOWN)
+    app.state = APP_STATE_IDLE;
 
   if (app.frameThread && !lgJoinThread(app.frameThread, NULL))
   {
@@ -234,7 +242,14 @@ bool stopThreads()
 
 static bool captureStart()
 {
-  DEBUG_INFO("Using            : %s", app.iface->getName());
+  if (app.state == APP_STATE_IDLE)
+  {
+    if (!app.iface->init())
+    {
+      DEBUG_ERROR("Initialize the capture device");
+      return false;
+    }
+  }
 
   const unsigned int maxFrameSize = app.iface->getMaxFrameSize();
   if (maxFrameSize > app.maxFrameSize)
@@ -248,31 +263,33 @@ static bool captureStart()
   return startThreads();
 }
 
-static bool captureRestart()
+static bool captureStop()
 {
-  DEBUG_INFO("==== [ Capture Restart ] ====");
+  DEBUG_INFO("==== [ Capture Stop ] ====");
   if (!stopThreads())
     return false;
 
-  if (!app.iface->deinit() || !app.iface->init())
+  if (!app.iface->deinit())
   {
-    DEBUG_ERROR("Failed to reinitialize the capture device");
+    DEBUG_ERROR("Failed to deinitialize the capture device");
     return false;
   }
 
-  if (!captureStart())
-    return false;
-
   return true;
 }
 
+static bool captureRestart()
+{
+  return captureStop() && captureStart();
+}
+
 bool captureGetPointerBuffer(void ** data, uint32_t * size)
 {
   // spin until there is room
   while(lgmpHostQueuePending(app.pointerQueue) == LGMP_Q_POINTER_LEN)
   {
     usleep(1);
-    if (!app.running)
+    if (app.state == APP_STATE_RUNNING)
       return false;
   }
 
@@ -522,6 +539,9 @@ int app_main(int argc, char * argv[])
     goto fail;
   }
 
+  DEBUG_INFO("Using            : %s", iface->getName());
+
+  app.state = APP_STATE_RUNNING;
   app.iface = iface;
 
   LG_LOCK_INIT(app.pointerLock);
@@ -532,20 +552,36 @@ int app_main(int argc, char * argv[])
     goto fail;
   }
 
+  while(app.state != APP_STATE_SHUTDOWN)
+  {
+    if(lgmpHostQueueHasSubs(app.pointerQueue) ||
+        lgmpHostQueueHasSubs(app.frameQueue))
+    {
       if (!captureStart())
       {
         exitcode = -1;
         goto exit;
       }
-
-  while(app.running)
+    }
+    else
     {
-    if (app.reinit && !captureRestart())
+      usleep(100);
+      continue;
+    }
+
+    while(app.state != APP_STATE_SHUTDOWN && (
+          lgmpHostQueueHasSubs(app.pointerQueue) ||
+          lgmpHostQueueHasSubs(app.frameQueue)))
+    {
+      if (app.state == APP_STATE_RESTART)
+      {
+        if (!captureRestart())
         {
           exitcode = -1;
           goto exit;
         }
-    app.reinit = false;
+        app.state = APP_STATE_RUNNING;
+      }
 
       if (lgmpHostQueueNewSubs(app.pointerQueue) > 0)
       {
@@ -563,12 +599,7 @@ int app_main(int argc, char * argv[])
           continue;
 
         case CAPTURE_RESULT_REINIT:
-        if (!captureRestart())
-        {
-          exitcode = -1;
-          goto exit;
-        }
-        app.reinit = false;
+          app.state = APP_STATE_RESTART;
           continue;
 
         case CAPTURE_RESULT_ERROR:
@@ -578,6 +609,11 @@ int app_main(int argc, char * argv[])
       }
     }
 
+    if (app.state != APP_STATE_SHUTDOWN)
+      DEBUG_INFO("No subscribers, going to sleep...");
+    captureStop();
+  }
+
 finish:
   stopThreads();
 
@@ -602,5 +638,5 @@ fail:
 
 void app_quit()
 {
-  app.running = false;
+  app.state = APP_STATE_SHUTDOWN;
 }

repos/LGMP

@@ -1 +1 @@
-Subproject commit 7d3b8a1d8b8a24f3812fb250b6e853f2c37ec483
+Subproject commit 2a1477550cc122dcac8af7016ac5f15dec2e139a