Force event loop to re-enter processing to handle queued messages

include/sdbus-c++/IConnection.h

@@ -64,6 +64,10 @@ namespace sdbus {
          */
         struct PollData
         {
+            /*!
+             * The read fd to be monitored by the event loop.
+             */
+            int event_fd;
             /*!
              * The read fd to be monitored by the event loop.
              */

src/Connection.cpp

@@ -75,11 +75,16 @@ Connection::Connection(std::unique_ptr<ISdBus>&& interface, pseudo_bus_t)
     , bus_(openPseudoBus())
 {
     assert(iface_ != nullptr);
+    eventFd_.fd = eventfd(0, 0);
+    assert(eventFd_.fd >= 0);
 }
 
 Connection::~Connection()
 {
     Connection::leaveEventLoop();
+    if (0 <= eventFd_.fd) {
+        close(eventFd_.fd);
+    }
 }
 
 void Connection::requestName(const std::string& name)
@@ -141,7 +146,7 @@ Connection::PollData Connection::getEventLoopPollData() const
     auto r = iface_->sd_bus_get_poll_data(bus_.get(), &pollData);
     SDBUS_THROW_ERROR_IF(r < 0, "Failed to get bus poll data", -r);
 
-    return {pollData.fd, pollData.events, pollData.timeout_usec};
+    return {eventFd_.fd, pollData.fd, pollData.events, pollData.timeout_usec};
 }
 
 const ISdBus& Connection::getSdBusInterface() const
@@ -445,6 +450,11 @@ void Connection::notifyEventLoopToExit() const
     notifyEventLoop(loopExitFd_.fd);
 }
 
+void Connection::notifyEventLoop() const
+{
+    notifyEventLoop(eventFd_.fd);
+}
+
 void Connection::notifyEventLoopNewTimeout() const
 {
     // The extra notifications for new timeouts are only needed if calls are made asynchronously to the event loop.

src/Connection.h

@@ -139,6 +139,7 @@ namespace sdbus::internal {
         void notifyEventLoop(int fd) const;
         void notifyEventLoopToExit() const;
         void clearEventLoopNotification(int fd) const;
+        void notifyEventLoop() const override;
         void notifyEventLoopNewTimeout() const override;
 
     private:

src/IConnection.h

@@ -90,6 +90,7 @@ namespace sdbus::internal {
                                                         , sd_bus_message_handler_t callback
                                                         , void* userData ) = 0;
 
+        virtual void notifyEventLoop() const = 0;
         virtual void notifyEventLoopNewTimeout() const = 0;
         virtual MethodReply tryCallMethodSynchronously(const MethodCall& message, uint64_t timeout) = 0;
     };

src/Message.cpp

@@ -782,6 +782,10 @@ MethodReply MethodCall::sendWithReply(uint64_t timeout) const
 
     SDBUS_THROW_ERROR_IF(r < 0, "Failed to call method", -r);
 
+    // Force event loop to re-enter processing to handle queued messages
+    SDBUS_THROW_ERROR_IF(connection_ == nullptr, "Invalid use of MethodCall API", ENOTSUP);
+    connection_->notifyEventLoop();
+
     return Factory::create<MethodReply>(sdbusReply, sdbus_, adopt_message);
 }
 
@@ -790,6 +794,10 @@ MethodReply MethodCall::sendWithNoReply() const
     auto r = sdbus_->sd_bus_send(nullptr, (sd_bus_message*)msg_, nullptr);
     SDBUS_THROW_ERROR_IF(r < 0, "Failed to call method with no reply", -r);
 
+    // Force event loop to re-enter processing to handle queued messages
+    SDBUS_THROW_ERROR_IF(connection_ == nullptr, "Invalid use of MethodCall API", ENOTSUP);
+    connection_->notifyEventLoop();
+
     return Factory::create<MethodReply>(); // No reply
 }