splitting video and webserver into different threads

main.cc

@@ -11,6 +11,7 @@
 
 int running = 1;
 
+pthread_mutex_t mtx;
 static void sig_int(int);   
 int SetupSignals();
 VideoFrame inputimage;
@@ -22,50 +23,59 @@ void ErrorExit(std::string text, int errorcode) {
 };
 
 
-int main(int argc, char **argv) {
-    VideoDevice *vdev= NULL;
+int Lock () {
+	if (pthread_mutex_lock(&mtx) == 0) return 1;
+	else return 0;
+};
 
-    printf ("MiniWebCam:\n");
-    if (SetupSignals() == 0) return 0;
 
-    config.LoadArgs (argc, argv);
-    config.LoadFile (config.GetFilename());
-    if (config.GetInitFlags() & CONF_INITFLAGS_PRINT) {
-        config.PrintConfig();
-        return 0;
-    }
+int UnLock () {
+	if (pthread_mutex_unlock(&mtx) == 0) return 1;
+	else return 0;
+};
 
-    if (config.GetInitFlags() & CONF_INITFLAGS_HELP) {
-        config.Help();
-        return 0;
+
+static void *thread_webserver(void *ignored_argument) {
+    WebCamServer webserver;
+
+    webserver.SetupPorts(config.http_port, config.https_port);
+    webserver.SetupSSL(config.ssl_key, config.ssl_cert);
+    webserver.Start();
+
+    while (running) {
+        webserver.Loop();
+        usleep (200);
     }
 
+    running = 0;    // force running to 0
+
+    webserver.Stop();
+    return NULL;
+};
+
+
+
+static void *thread_video(void *ignored_argument) {
+    VideoDevice *vdev= NULL;
+
     if (config.vdev_dumpfile.length() > 0) {
         vdev = new VideoDevice_Dump();
     }
     else {
         vdev = new VideoDevice_V4L2();
     }
-    WebCamServer webserver;
-    currentimage.TestScreen(1920, 1080);
-
-    webserver.SetupPorts(config.http_port, config.https_port);
-    webserver.SetupSSL(config.ssl_key, config.ssl_cert);
-    webserver.Start();
 
     if (vdev->SetDevice (config.vdev_device, config.vdev_width, config.vdev_height, convert_to_pixelformat(config.vdev_format)) == 0) {
         debug ("could not setup device.\n");
-        return 0;
+        goto thread_video_exit;                     // we use goto for a better cleanup of the thread
     }
-
     if (vdev->SetIOMode (config.vdev_iomode) == 0) {
         debug ("could not setup iomode.\n");
-        return 0;
+        goto thread_video_exit;
     }
-
     if (vdev->Start() == 0) {
         debug ("Error: could not start video.\n");
-        return 0;
+        goto thread_video_exit;
     }
 
     currentimage.SetSize (config.web_width, config.web_height);
@@ -75,15 +85,52 @@ int main(int argc, char **argv) {
             vdev->Stop();
             vdev->Start();
         }
+        Lock();
         inputimage.CopyTo(&currentimage, config.web_width, config.web_height);
-        
-        webserver.Loop();
-        usleep (1000);
+        UnLock();
     }
 
+thread_video_exit:
+    running = 0;        // force the other threads to stop
     vdev->Stop();
-    webserver.Stop();
+    delete vdev;
+    vdev = NULL;
+    return NULL;
+}
+
+
+
+int main(int argc, char **argv) {
+    pthread_t thr_webserver;
+    pthread_t thr_video;
+
+    printf ("MiniWebCam:\n");
+
+    // prepare signals, mutex and test output image
+    if (SetupSignals() == 0) return 0;
+    pthread_mutex_init(&mtx, NULL);
+    currentimage.TestScreen(1920, 1080);
+
+    // read and setup config
+    config.LoadArgs (argc, argv);
+    config.LoadFile (config.GetFilename());
+    if (config.GetInitFlags() & CONF_INITFLAGS_PRINT) {
+        config.PrintConfig();
+        return 0;
+    }
 
+    if (config.GetInitFlags() & CONF_INITFLAGS_HELP) {
+        config.Help();
+        return 0;
+    }
+
+    pthread_create(&thr_webserver, NULL, &thread_webserver, NULL);
+    pthread_create(&thr_video, NULL, &thread_video, NULL);
+
+    while (running) {
+        usleep (1000);
+    }
+    
 	return 0;
 };
 

miniwebcam.h

@@ -23,6 +23,8 @@ class WebCamServer : public WebServer {
 
 
 void ErrorExit(std::string text, int errorcode);
+int Lock();
+int UnLock();
 
 extern VideoFrame currentimage;
 

webserver.cc

@@ -23,7 +23,9 @@ int WebCamServer::HandleRequest (WebRequestBuffer *requestbuffer, WebServerClien
     }
     else if (request.find("/snapshot.jpg") != std::string::npos) {
         InMemoryFile jpgfile;
+        Lock();
         currentimage.ConvertToJpeg(&jpgfile, 99);
+        UnLock();
         if (webclient->SendResponseFileFromMemory(requestbuffer, request, "", 
                                               (void*) jpgfile.mem, 
                                               jpgfile.memsize) != 1) return 0;