Add noexcept qualifications on the plugin side

See the last few commits.

src/plugin/bridges/common.h

@@ -105,7 +105,7 @@ class PluginBridge {
               io_context.run();
           }) {}
 
-    virtual ~PluginBridge(){};
+    virtual ~PluginBridge() noexcept {};
 
    protected:
     /**

src/plugin/bridges/vst2.cpp

@@ -31,7 +31,7 @@ float get_parameter_proxy(AEffect*, int);
  * is sadly needed as a workaround to avoid using globals since we need free
  * function pointers to interface with the VST C API.
  */
-Vst2PluginBridge& get_bridge_instance(const AEffect& plugin) {
+Vst2PluginBridge& get_bridge_instance(const AEffect& plugin) noexcept {
     return *static_cast<Vst2PluginBridge*>(plugin.ptr3);
 }
 
@@ -168,20 +168,26 @@ Vst2PluginBridge::Vst2PluginBridge(audioMasterCallback host_callback)
     update_aeffect(plugin, initialized_plugin);
 }
 
-Vst2PluginBridge::~Vst2PluginBridge() {
-    // Drop all work make sure all sockets are closed
-    plugin_host->terminate();
+Vst2PluginBridge::~Vst2PluginBridge() noexcept {
+    try {
+        // Drop all work make sure all sockets are closed
+        plugin_host->terminate();
 
-    // The `stop()` method will cause the IO context to just drop all of its
-    // outstanding work immediately
-    io_context.stop();
+        // The `stop()` method will cause the IO context to just drop all of its
+        // outstanding work immediately
+        io_context.stop();
+    } catch (const boost::system::system_error&) {
+        // It could be that the sockets have already been closed or that the
+        // process has already exited (at which point we probably won't be
+        // executing this, but maybe if all the stars align)
+    }
 }
 
 class DispatchDataConverter : DefaultDataConverter {
    public:
     DispatchDataConverter(std::vector<uint8_t>& chunk_data,
                           AEffect& plugin,
-                          VstRect& editor_rectangle)
+                          VstRect& editor_rectangle) noexcept
         : chunk(chunk_data), plugin(plugin), rect(editor_rectangle) {}
 
     EventPayload read(const int opcode,

src/plugin/bridges/vst2.h

@@ -52,7 +52,7 @@ class Vst2PluginBridge : PluginBridge<Vst2Sockets<std::jthread>> {
      * Terminate the Wine plugin host process and drop all work when the module
      * gets unloaded.
      */
-    ~Vst2PluginBridge();
+    ~Vst2PluginBridge() noexcept override;
 
     // The four below functions are the handlers from the VST2 API. They are
     // called through proxy functions in `plugin.cpp`.

src/plugin/bridges/vst3.cpp

@@ -363,10 +363,16 @@ Vst3PluginBridge::Vst3PluginBridge()
     });
 }
 
-Vst3PluginBridge::~Vst3PluginBridge() {
-    // Drop all work make sure all sockets are closed
-    plugin_host->terminate();
-    io_context.stop();
+Vst3PluginBridge::~Vst3PluginBridge() noexcept {
+    try {
+        // Drop all work make sure all sockets are closed
+        plugin_host->terminate();
+        io_context.stop();
+    } catch (const boost::system::system_error&) {
+        // It could be that the sockets have already been closed or that the
+        // process has already exited (at which point we probably won't be
+        // executing this, but maybe if all the stars align)
+    }
 }
 
 Steinberg::IPluginFactory* Vst3PluginBridge::get_plugin_factory() {

src/plugin/bridges/vst3.h

@@ -53,13 +53,13 @@ class Vst3PluginBridge : PluginBridge<Vst3Sockets<std::jthread>> {
      * @throw std::runtime_error Thrown when the Wine plugin host could not be
      *   found, or if it could not locate and load a VST3 module.
      */
-    Vst3PluginBridge();
+    explicit Vst3PluginBridge();
 
     /**
      * Terminate the Wine plugin host process and drop all work when the module
      * gets unloaded.
      */
-    ~Vst3PluginBridge();
+    ~Vst3PluginBridge() noexcept;
 
     /**
      * When the host loads the module it will call `GetPluginFactory()` which

src/plugin/host-process.cpp

@@ -64,6 +64,8 @@ HostProcess::HostProcess(boost::asio::io_context& io_context,
     logger.async_log_pipe_lines(stderr_pipe, stderr_buffer, "[Wine STDERR] ");
 }
 
+HostProcess::~HostProcess() noexcept {}
+
 IndividualHost::IndividualHost(boost::asio::io_context& io_context,
                                Logger& logger,
                                const PluginInfo& plugin_info,
@@ -108,7 +110,7 @@ fs::path IndividualHost::path() {
     return host_path;
 }
 
-bool IndividualHost::running() {
+bool IndividualHost::running() noexcept {
     return host.running();
 }
 
@@ -219,7 +221,7 @@ fs::path GroupHost::path() {
     return host_path;
 }
 
-bool GroupHost::running() {
+bool GroupHost::running() noexcept {
     // When we are unable to connect to a new or existing group host process,
     // then we'll consider the startup failed and we'll allow the initialization
     // process to terminate.

src/plugin/host-process.h

@@ -40,7 +40,7 @@
  */
 class HostProcess {
    public:
-    virtual ~HostProcess(){};
+    virtual ~HostProcess() noexcept;
 
     /**
      * Return the full path to the host application in use. The host application
@@ -53,7 +53,7 @@ class HostProcess {
      * Return true if the host process is still running. Used during startup to
      * abort connecting to sockets if the Wine process has crashed.
      */
-    virtual bool running() = 0;
+    virtual bool running() noexcept = 0;
 
     /**
      * Kill the process or cause the plugin that's being hosted to exit.
@@ -133,7 +133,7 @@ class IndividualHost : public HostProcess {
                    Sockets& sockets);
 
     boost::filesystem::path path() override;
-    bool running() override;
+    bool running() noexcept override;
     void terminate() override;
 
    private:
@@ -180,7 +180,7 @@ class GroupHost : public HostProcess {
               std::string group_name);
 
     boost::filesystem::path path() override;
-    bool running() override;
+    bool running() noexcept override;
     void terminate() override;
 
    private: