Wait using a condition variable in server

Currently, server_stop() is called from the same thread as
server_connect_to(), so interruption may never happen.

This is a step to prepare executing the server from a dedicated thread.

app/src/server.c

@@ -367,7 +367,8 @@ connect_and_read_byte(sc_socket socket, uint16_t port) {
 }
 
 static sc_socket
-connect_to_server(uint16_t port, uint32_t attempts, uint32_t delay) {
+connect_to_server(struct server *server, uint32_t attempts, sc_tick delay) {
+    uint16_t port = server->local_port;
     do {
         LOGD("Remaining connection attempts: %d", (int) attempts);
         sc_socket socket = net_socket();
@@ -381,7 +382,20 @@ connect_to_server(uint16_t port, uint32_t attempts, uint32_t delay) {
             net_close(socket);
         }
         if (attempts) {
-            SDL_Delay(delay);
+            sc_mutex_lock(&server->mutex);
+            sc_tick deadline = sc_tick_now() + delay;
+            bool timed_out = false;
+            while (!server->stopped && !timed_out) {
+                timed_out = !sc_cond_timedwait(&server->cond_stopped,
+                                               &server->mutex, deadline);
+            }
+            bool stopped = server->stopped;
+            sc_mutex_unlock(&server->mutex);
+
+            if (stopped) {
+                LOGI("Connection attempt stopped");
+                break;
+            }
         }
     } while (--attempts > 0);
     return SC_INVALID_SOCKET;
@@ -395,7 +409,23 @@ server_init(struct server *server, const struct server_params *params) {
         return false;
     }
 
+    ok = sc_mutex_init(&server->mutex);
+    if (!ok) {
+        LOGE("Could not create server mutex");
+        server_params_destroy(&server->params);
+        return false;
+    }
+
+    ok = sc_cond_init(&server->cond_stopped);
+    if (!ok) {
+        LOGE("Could not create server cond_stopped");
+        sc_mutex_destroy(&server->mutex);
+        server_params_destroy(&server->params);
+        return false;
+    }
+
     server->process = SC_PROCESS_NONE;
+    server->stopped = false;
 
     server->server_socket = SC_INVALID_SOCKET;
     server->video_socket = SC_INVALID_SOCKET;
@@ -453,8 +483,8 @@ server_connect_to(struct server *server, struct server_info *info) {
         server->server_socket = SC_INVALID_SOCKET;
     } else {
         uint32_t attempts = 100;
-        uint32_t delay = 100; // ms
-        video_socket = connect_to_server(server->local_port, attempts, delay);
+        sc_tick delay = SC_TICK_FROM_MS(100);
+        video_socket = connect_to_server(server, attempts, delay);
         if (video_socket == SC_INVALID_SOCKET) {
             goto fail;
         }
@@ -563,6 +593,11 @@ error:
 
 void
 server_stop(struct server *server) {
+    sc_mutex_lock(&server->mutex);
+    server->stopped = true;
+    sc_cond_signal(&server->cond_stopped);
+    sc_mutex_unlock(&server->mutex);
+
     if (server->server_socket != SC_INVALID_SOCKET) {
         if (!net_interrupt(server->server_socket)) {
             LOGW("Could not interrupt server socket");
@@ -627,4 +662,6 @@ server_destroy(struct server *server) {
         }
     }
     server_params_destroy(&server->params);
+    sc_cond_destroy(&server->cond_stopped);
+    sc_mutex_destroy(&server->mutex);
 }

app/src/server.h

@@ -47,6 +47,10 @@ struct server {
     // alive only between start() and stop()
     struct sc_process_observer observer;
 
+    sc_mutex mutex;
+    sc_cond cond_stopped;
+    bool stopped;
+
     sc_socket server_socket; // only used if !tunnel_forward
     sc_socket video_socket;
     sc_socket control_socket;