Move the host guard handler to PluginBridge

src/plugin/bridges/common.h

@@ -37,8 +37,8 @@ class PluginBridge {
    public:
     /**
      * Sets up everything needed to start the host process. Classes deriving
-     * from this should call `log_init_message()` themselves after their
-     * initialization list.
+     * from this should call `log_init_message()` and
+     * `connect_sockets_guarded()` themselves after their initialization list.
      *
      * @param plugin_type The type of the plugin we're handling.
      * @param plugin_path The path to the plugin. For VST2 plugins this is the
@@ -197,6 +197,47 @@ class PluginBridge {
         }
     }
 
+    /**
+     * Connect the sockets, while starting another thread that will terminate
+     * the plugin (through `std::terminate`/SIGABRT) when the host process fails
+     * to start. This is the only way to stop listening on our sockets without
+     * moving everything over to asynchronous listeners (which may actually be a
+     * good idea just for this use case). Otherwise the plugin would be stuck
+     * loading indefinitely when Wine is not configured correctly.
+     *
+     * TODO: Asynchronously connect our sockets so we can interrupt it, maybe
+     */
+    void connect_sockets_guarded() {
+#ifndef WITH_WINEDBG
+        // If the Wine process fails to start, then nothing will connect to the
+        // sockets and we'll be hanging here indefinitely. To prevent this,
+        // we'll periodically poll whether the Wine process is still running,
+        // and throw when it is not. The alternative would be to rewrite this to
+        // using `async_accept`, Boost.Asio timers, and another IO context, but
+        // I feel like this a much simpler solution.
+        host_guard_handler = std::jthread([&](std::stop_token st) {
+            using namespace std::literals::chrono_literals;
+
+            while (!st.stop_requested()) {
+                if (!plugin_host->running()) {
+                    generic_logger.log(
+                        "The Wine host process has exited unexpectedly. Check "
+                        "the "
+                        "output above for more information.");
+                    std::terminate();
+                }
+
+                std::this_thread::sleep_for(20ms);
+            }
+        });
+#endif
+
+        sockets.connect();
+#ifndef WITH_WINEDBG
+        host_guard_handler.request_stop();
+#endif
+    }
+
     /**
      * The type of the plugin we're dealing with. Passed to the host process and
      * printed in the initialisation message.
@@ -224,7 +265,10 @@ class PluginBridge {
     /**
      * The sockets used for communication with the Wine process.
      *
-     * @see PluginBridge::log_init_message
+     * @remark `sockets.connect()` should not be called directly.
+     * `connect_sockets_guarded()` should be used instead.
+     *
+     * @see PluginBridge::connect_sockets_guarded
      */
     TSockets sockets;
 
@@ -263,4 +307,14 @@ class PluginBridge {
      * STDOUT and STDERR messages.
      */
     std::jthread wine_io_handler;
+
+   private:
+    /**
+     * A thread used during the initialisation process to terminate listening on
+     * the sockets if the Wine process cannot start for whatever reason. This
+     * has to be defined here instead of in the constructor we can't simply
+     * detach the thread as it has to check whether the VST host is still
+     * running.
+     */
+    std::jthread host_guard_handler;
 };

src/plugin/bridges/vst2.cpp

@@ -61,36 +61,9 @@ Vst2PluginBridge::Vst2PluginBridge(audioMasterCallback host_callback)
           create_logger_prefix(sockets.base_dir)))) {
     log_init_message();
 
-    // TODO: Also move his to `PluginHost`
-#ifndef WITH_WINEDBG
-    // If the Wine process fails to start, then nothing will connect to the
-    // sockets and we'll be hanging here indefinitely. To prevent this, we'll
-    // periodically poll whether the Wine process is still running, and throw
-    // when it is not. The alternative would be to rewrite this to using
-    // `async_accept`, Boost.Asio timers, and another IO context, but I feel
-    // like this a much simpler solution.
-    host_guard_handler = std::jthread([&](std::stop_token st) {
-        using namespace std::literals::chrono_literals;
-
-        while (!st.stop_requested()) {
-            if (!plugin_host->running()) {
-                logger.log(
-                    "The Wine host process has exited unexpectedly. Check the "
-                    "output above for more information.");
-                std::terminate();
-            }
-
-            std::this_thread::sleep_for(20ms);
-        }
-    });
-#endif
-
     // This will block until all sockets have been connected to by the Wine VST
     // host
-    sockets.connect();
-#ifndef WITH_WINEDBG
-    host_guard_handler.request_stop();
-#endif
+    connect_sockets_guarded();
 
     // Set up all pointers for our `AEffect` struct. We will fill this with data
     // from the VST plugin loaded in Wine at the end of this constructor.

src/plugin/bridges/vst2.h

@@ -148,15 +148,6 @@ class Vst2PluginBridge : PluginBridge<Vst2Sockets<std::jthread>> {
      */
     Vst2Logger logger;
 
-    /**
-     * A thread used during the initialisation process to terminate listening on
-     * the sockets if the Wine process cannot start for whatever reason. This
-     * has to be defined here instead of in the constructor we can't simply
-     * detach the thread as it has to check whether the VST host is still
-     * running.
-     */
-    std::jthread host_guard_handler;
-
     /**
      * A scratch buffer for sending and receiving data during `process`,
      * `processReplacing` and `processDoubleReplacing` calls.

src/plugin/bridges/vst3.cpp

@@ -34,5 +34,7 @@ Vst3PluginBridge::Vst3PluginBridge()
           create_logger_prefix(sockets.base_dir)))) {
     log_init_message();
 
-    // TODO: Call the host guard handler
+    // This will block until all sockets have been connected to by the Wine VST
+    // host
+    connect_sockets_guarded();
 }