Add ServerStartedCondition to hold the mutex, condition variable and condition. Changes allow callers to correctly handle spurious wakeups.

test/cpp/interop/interop_server.cc

@@ -323,7 +323,7 @@ void grpc::testing::interop::RunServer(
 void grpc::testing::interop::RunServer(
     std::shared_ptr<ServerCredentials> creds,
     const int port,
-    std::condition_variable *server_started_condition) {
+    ServerStartedCondition *server_started_condition) {
   GPR_ASSERT(port != 0);
   std::ostringstream server_address;
   server_address << "0.0.0.0:" << port;
@@ -342,7 +342,11 @@ void grpc::testing::interop::RunServer(
   gpr_log(GPR_INFO, "Server listening on %s", server_address.str().c_str());
 
   // Signal that the server has started.
-  if (server_started_condition) server_started_condition->notify_all();
+  if (server_started_condition) {
+    std::unique_lock<std::mutex> lock(server_started_condition->mutex);
+    server_started_condition->server_started = true;
+    server_started_condition->condition.notify_all();
+  }
 
   while (!gpr_atm_no_barrier_load(&g_got_sigint)) {
     gpr_sleep_until(gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),

test/cpp/interop/server_helper.h

@@ -52,6 +52,12 @@ namespace interop {
 
 extern gpr_atm g_got_sigint;
 
+struct ServerStartedCondition {
+  std::mutex mutex;
+  std::condition_variable condition;
+  bool server_started = false;
+};
+
 /// Run gRPC interop server using port FLAGS_port.
 ///
 /// \param creds The credentials associated with the server.
@@ -61,11 +67,11 @@ void RunServer(std::shared_ptr<ServerCredentials> creds);
 ///
 /// \param creds The credentials associated with the server.
 /// \param port Port to use for the server.
-/// \param server_started_condition (optional) Condition variable used to notify
+/// \param server_started_condition (optional) Struct holding mutex, condition
-///     when the server has started.
+///     variable, and condition used to notify when the server has started.
 void RunServer(std::shared_ptr<ServerCredentials> creds,
                int port,
-               std::condition_variable *server_started_condition);
+               ServerStartedCondition *server_started_condition);
 
 }  // namespace interop
 }  // namespace testing