Create base class for sockets and derive from that

Now the host launching procedure can be agnostic of the socket
implementation.

src/common/communication/common.h

@@ -139,6 +139,79 @@ inline T read_object(Socket& socket) {
     return read_object<T>(socket, buffer);
 }
 
+/**
+ * Generate a unique base directory that can be used as a prefix for all Unix
+ * domain socket endpoints used in `Vst2PluginBridge`/`Vst2Bridge`. This will
+ * usually return `/run/user/<uid>/yabridge-<plugin_name>-<random_id>/`.
+ *
+ * Sockets for group hosts are handled separately. See
+ * `../plugin/utils.h:generate_group_endpoint` for more information on those.
+ *
+ * @param plugin_name The name of the plugin we're generating endpoints for.
+ *   Used as a visual indication of what plugin is using this endpoint.
+ */
+boost::filesystem::path generate_endpoint_base(const std::string& plugin_name);
+
+/**
+ * Manages all the sockets used for communicating between the plugin and the
+ * Wine host. Every plugin will get its own directory (the socket endpoint base
+ * directory), and all socket endpoints are created within this directory. This
+ * is usually `/run/user/<uid>/yabridge-<plugin_name>-<random_id>/`.
+ */
+class Sockets {
+   public:
+    /**
+     * Sets up the the base directory for the sockets. Classes inheriting this
+     * should set up their sockets here.
+     *
+     * @param endpoint_base_dir The base directory that will be used for the
+     *   Unix domain sockets.
+     *
+     * @see Sockets::connect
+     */
+    Sockets(const boost::filesystem::path& endpoint_base_dir)
+        : base_dir(endpoint_base_dir) {}
+
+    /**
+     * Shuts down and closes all sockets and then cleans up the directory
+     * containing the socket endpoints when yabridge shuts down if it still
+     * exists.
+     *
+     * @note Classes overriding this should call `close()` in their destructor.
+     */
+    virtual ~Sockets() {
+        try {
+            boost::filesystem::remove_all(base_dir);
+        } catch (const boost::filesystem::filesystem_error&) {
+            // There should not be any filesystem errors since only one side
+            // removes the files, but if we somehow can't delete the file
+            // then we can just silently ignore this
+        }
+    }
+
+    /**
+     * Depending on the value of the `listen` argument passed to the
+     * constructor, either accept connections made to the sockets on the Linux
+     * side or connect to the sockets on the Wine side
+     */
+    virtual void connect() = 0;
+
+    /**
+     * Shut down and close all sockets. Called during the destructor and also
+     * explicitly called when shutting down a plugin in a group host process.
+     *
+     * It should be safe to call this function more than once, and it should be
+     * called in the overridden class's destructor.
+     */
+    virtual void close() = 0;
+
+    /**
+     * The base directory for our socket endpoints. All `*_endpoint` variables
+     * below are files within this directory.
+     */
+    const boost::filesystem::path base_dir;
+};
+
 /**
  * A single, long-living socket
  */
@@ -154,7 +227,7 @@ class SocketHandler {
      *   connections will be accepted when `connect()` gets called. This should
      *   be set to `true` on the plugin side, and `false` on the Wine host side.
      *
-     * @see Vst2Sockets::connect
+     * @see Sockets::connect
      */
     SocketHandler(boost::asio::io_context& io_context,
                   boost::asio::local::stream_protocol::endpoint endpoint,
@@ -304,16 +377,3 @@ class SocketHandler {
      */
     std::optional<boost::asio::local::stream_protocol::acceptor> acceptor;
 };
-
-/**
- * Generate a unique base directory that can be used as a prefix for all Unix
- * domain socket endpoints used in `Vst2PluginBridge`/`Vst2Bridge`. This will
- * usually return `/run/user/<uid>/yabridge-<plugin_name>-<random_id>/`.
- *
- * Sockets for group hosts are handled separately. See
- * `../plugin/utils.h:generate_group_endpoint` for more information on those.
- *
- * @param plugin_name The name of the plugin we're generating endpoints for.
- *   Used as a visual indication of what plugin is using this endpoint.
- */
-boost::filesystem::path generate_endpoint_base(const std::string& plugin_name);

src/common/communication/vst2.h

@@ -124,7 +124,7 @@ class EventHandler {
      *   connections will be accepted when `connect()` gets called. This should
      *   be set to `true` on the plugin side, and `false` on the Wine host side.
      *
-     * @see Vst2Sockets::connect
+     * @see Sockets::connect
      */
     EventHandler(boost::asio::io_context& io_context,
                  boost::asio::local::stream_protocol::endpoint endpoint,
@@ -448,7 +448,7 @@ class EventHandler {
 
     /**
      * This acceptor will be used once synchronously on the listening side
-     * during `Vst2Sockets::connect()`. When `EventHandler::receive_events()` is
+     * during `Sockets::connect()`. When `EventHandler::receive_events()` is
      * then called, we'll recreate the acceptor to asynchronously listen for new
      * incoming socket connections on `endpoint` using. This is important,
      * because on the case of `vst_host_callback` the acceptor is first accepts
@@ -467,9 +467,7 @@ class EventHandler {
 
 /**
  * Manages all the sockets used for communicating between the plugin and the
- * Wine host. Every plugin will get its own directory (the socket endpoint base
- * directory), and all socket endpoints are created within this directory. This
- * is usually `/run/user/<uid>/yabridge-<plugin_name>-<random_id>/`.
+ * Wine host when hosting a VST2 plugin.
  *
  * On the plugin side this class should be initialized with `listen` set to
  * `true` before launching the Wine VST host. This will start listening on the
@@ -480,7 +478,7 @@ class EventHandler {
  *   should be `std::jthread` and on the Wine side this should be `Win32Thread`.
  */
 template <typename Thread>
-class Vst2Sockets {
+class Vst2Sockets : public Sockets {
    public:
     /**
      * Sets up the sockets using the specified base directory. The sockets won't
@@ -499,7 +497,7 @@ class Vst2Sockets {
     Vst2Sockets(boost::asio::io_context& io_context,
                 const boost::filesystem::path& endpoint_base_dir,
                 bool listen)
-        : base_dir(endpoint_base_dir),
+        : Sockets(endpoint_base_dir),
           host_vst_dispatch(io_context,
                             (base_dir / "host_vst_dispatch.sock").string(),
                             listen),
@@ -517,36 +515,9 @@ class Vst2Sockets {
                            (base_dir / "host_vst_control.sock").string(),
                            listen) {}
 
-    /**
-     * Cleans up the directory containing the socket endpoints when yabridge
-     * shuts down if it still exists.
-     */
-    ~Vst2Sockets() {
-        // Manually close all sockets so we break out of any blocking operations
-        // that may still be active
-        host_vst_dispatch.close();
-        vst_host_callback.close();
-        host_vst_parameters.close();
-        host_vst_process_replacing.close();
-        host_vst_control.close();
+    ~Vst2Sockets() { close(); }
 
-        // Only clean if we're the ones who have created these files, although
-        // it should not cause any harm to also do this on the Wine side
-        try {
-            boost::filesystem::remove_all(base_dir);
-        } catch (const boost::filesystem::filesystem_error&) {
-            // There should not be any filesystem errors since only one side
-            // removes the files, but if we somehow can't delete the file
-            // then we can just silently ignore this
-        }
-    }
-
-    /**
-     * Depending on the value of the `listen` argument passed to the
-     * constructor, either accept connections made to the sockets on the Linux
-     * side or connect to the sockets on the Wine side
-     */
-    void connect() {
+    void connect() override {
         host_vst_dispatch.connect();
         vst_host_callback.connect();
         host_vst_parameters.connect();
@@ -554,11 +525,15 @@ class Vst2Sockets {
         host_vst_control.connect();
     }
 
-    /**
-     * The base directory for our socket endpoints. All `*_endpoint` variables
-     * below are files within this directory.
-     */
-    const boost::filesystem::path base_dir;
+    void close() override {
+        // Manually close all sockets so we break out of any blocking operations
+        // that may still be active
+        host_vst_dispatch.close();
+        vst_host_callback.close();
+        host_vst_parameters.close();
+        host_vst_process_replacing.close();
+        host_vst_control.close();
+    }
 
     // The naming convention for these sockets is `<from>_<to>_<event>`. For
     // instance the socket named `host_vst_dispatch` forwards

src/plugin/host-process.cpp

@@ -87,7 +87,7 @@ void HostProcess::async_log_pipe_lines(patched_async_pipe& pipe,
 IndividualHost::IndividualHost(boost::asio::io_context& io_context,
                                Logger& logger,
                                fs::path plugin_path,
-                               const Vst2Sockets<std::jthread>& sockets)
+                               const Sockets& sockets)
     : HostProcess(io_context, logger),
       plugin_arch(find_vst_architecture(plugin_path)),
       host_path(find_vst_host(plugin_arch, false)),
@@ -134,7 +134,7 @@ void IndividualHost::terminate() {
 GroupHost::GroupHost(boost::asio::io_context& io_context,
                      Logger& logger,
                      fs::path plugin_path,
-                     Vst2Sockets<std::jthread>& sockets,
+                     Sockets& sockets,
                      std::string group_name)
     : HostProcess(io_context, logger),
       plugin_arch(find_vst_architecture(plugin_path)),
@@ -251,8 +251,8 @@ bool GroupHost::running() {
 void GroupHost::terminate() {
     // There's no need to manually terminate group host processes as they will
     // shut down automatically after all plugins have exited. Manually closing
-    // the dispatch socket will cause the associated plugin to exit.
-    sockets.host_vst_dispatch.close();
+    // the sockets will cause the associated plugin to exit.
+    sockets.close();
 }
 
 bool pid_running(pid_t pid) {

src/plugin/host-process.h

@@ -25,10 +25,7 @@
 #include <boost/process/child.hpp>
 #include <thread>
 
-// TODO: Those host process implementation now directly uses the Vst2Sockets and
-//       thus requires `communication/vst2.h`. We should create a simple common
-//       interface for this instead.
-#include "../common/communication/vst2.h"
+#include "../common/communication/common.h"
 #include "../common/logging.h"
 #include "utils.h"
 
@@ -130,7 +127,7 @@ class IndividualHost : public HostProcess {
     IndividualHost(boost::asio::io_context& io_context,
                    Logger& logger,
                    boost::filesystem::path plugin_path,
-                   const Vst2Sockets<std::jthread>& sockets);
+                   const Sockets& sockets);
 
     PluginArchitecture architecture() override;
     boost::filesystem::path path() override;
@@ -172,7 +169,7 @@ class GroupHost : public HostProcess {
     GroupHost(boost::asio::io_context& io_context,
               Logger& logger,
               boost::filesystem::path plugin_path,
-              Vst2Sockets<std::jthread>& socket_endpoint,
+              Sockets& socket_endpoint,
               std::string group_name);
 
     PluginArchitecture architecture() override;
@@ -206,7 +203,7 @@ class GroupHost : public HostProcess {
      * The associated sockets for the plugin we're hosting. This is used to
      * terminate the plugin.
      */
-    Vst2Sockets<std::jthread>& sockets;
+    Sockets& sockets;
 
     /**
      * A thread that waits for the group host to have started and then ask it to

src/wine-host/bridges/vst2.h

@@ -59,7 +59,7 @@ class Vst2Bridge {
      * @param plugin_dll_path A (Unix style) path to the VST plugin .dll file to
      *   load.
      * @param endpoint_base_dir The base directory used for the socket
-     *   endpoints. See `Vst2Sockets` for more information.
+     *   endpoints. See `Sockets` for more information.
      *
      * @note The object has to be constructed from the same thread that calls
      *   `main_context.run()`.