request_callback impl on windows standalone (#293)

* request_callback impl on windows standalone * replaced atomic load and set with exchange, handle case where timer start fails --------- Co-authored-by: MeijisIrlnd <[email protected]>
free-audio · Aug 17, 2024 · d066aab · d066aab
1 parent 3445292
commit d066aab
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Showing 5 changed files with 48 additions and 2 deletions.
diff --git a/src/detail/standalone/standalone_host.h b/src/detail/standalone/standalone_host.h
@@ -117,9 +117,10 @@ struct StandaloneHost : Clap::IHost
   {
     TRACE;
   }
+  std::atomic<bool> callbackRequested{false};
   void request_callback() override
   {
-    TRACE;
+    callbackRequested = true;
   }
   void setupWrapperSpecifics(const clap_plugin_t *plugin) override
   {

diff --git a/src/detail/standalone/windows/helpers.cpp b/src/detail/standalone/windows/helpers.cpp
@@ -70,6 +70,17 @@ double getScale(::HWND window)
   return static_cast<double>(::GetDpiForWindow(window)) / static_cast<double>(USER_DEFAULT_SCREEN_DPI);
 }
 
+bool startTimer(::HWND window, UINT_PTR timerId, UINT intervalMs)
+{
+  const auto res = ::SetTimer(window, timerId, intervalMs, (::TIMERPROC)NULL);
+  return res != 0;
+}
+
+bool stopTimer(::HWND window, UINT_PTR timerId)
+{
+  return ::KillTimer(window, timerId);
+}
+
 void abort(unsigned int exitCode)
 {
   ::ExitProcess(exitCode);

diff --git a/src/detail/standalone/windows/helpers.h b/src/detail/standalone/windows/helpers.h
@@ -34,6 +34,8 @@ bool closeWindow(::HWND window);
 bool checkWindowVisibility(::HWND window);
 unsigned int getCurrentDpi(::HWND window);
 double getScale(::HWND window);
+bool startTimer(::HWND window, UINT_PTR timerId, UINT intervalMs);
+bool stopTimer(::HWND window, UINT_PTR timerId);
 
 void abort(unsigned int exitCode = EXIT_FAILURE);
 void quit(unsigned int exitCode = EXIT_SUCCESS);

diff --git a/src/detail/standalone/windows/host_window.cpp b/src/detail/standalone/windows/host_window.cpp
@@ -10,6 +10,10 @@
 
 namespace freeaudio::clap_wrapper::standalone::windows
 {
+// We could also just have these at the call-site, but this kinda makes them easier to find.
+static constexpr auto s_timerId{0};
+static constexpr auto s_timerIntervalMs{8};
+
 HostWindow::HostWindow(std::shared_ptr<Clap::Plugin> clapPlugin)
   : m_clapPlugin{clapPlugin}
   , m_plugin{m_clapPlugin->_plugin}
@@ -73,6 +77,12 @@ void HostWindow::setupStandaloneHost()
 {
   freeaudio::clap_wrapper::standalone::getStandaloneHost()->onRequestResize =
       [this](uint32_t width, uint32_t height) { return setWindowSize(width, height); };
+  // Launch our timer
+  m_isTimerRunning = helpers::startTimer(m_hWnd.get(), s_timerId, s_timerIntervalMs);
+  if (!m_isTimerRunning)
+  {
+    TRACE;  // maybe
+  }
 }
 
 void HostWindow::setupPlugin()
@@ -137,6 +147,8 @@ LRESULT CALLBACK HostWindow::wndProc(::HWND hWnd, ::UINT uMsg, ::WPARAM wParam,
         return self->onSysCommand(hWnd, uMsg, wParam, lParam);
       case WM_DESTROY:
         return self->onDestroy();
+      case WM_TIMER:
+        return self->onTimerEvent(wParam);
     }
   }
 
@@ -300,11 +312,30 @@ int HostWindow::onSysCommand(::HWND hWnd, ::UINT uMsg, ::WPARAM wParam, ::LPARAM
 int HostWindow::onDestroy()
 {
   m_pluginGui->destroy(m_plugin);
+  if (m_isTimerRunning)
+  {
+    if (!helpers::stopTimer(m_hWnd.get(), s_timerId))
+    {
+      // We can grab the error with ::GetLastError, and format it with ::FormatMessage - but not sure if that's overkill
+      TRACE;
+    }
+  }
 
   freeaudio::clap_wrapper::standalone::mainFinish();
 
   helpers::quit();
 
   return 0;
 }
+
+int HostWindow::onTimerEvent(::WPARAM wParam)
+{
+  if (wParam != s_timerId) return -1;  // or assert fail, etc
+  auto* standaloneHost = freeaudio::clap_wrapper::standalone::getStandaloneHost();
+  if (standaloneHost->callbackRequested.exchange(false))
+  {
+    m_plugin->on_main_thread(m_plugin);
+  }
+  return 0;
+}
 }  // namespace freeaudio::clap_wrapper::standalone::windows
diff --git a/src/detail/standalone/windows/host_window.h b/src/detail/standalone/windows/host_window.h
@@ -24,13 +24,14 @@ struct HostWindow
   int onWindowPosChanged(::LPARAM lParam);
   int onSysCommand(::HWND hWnd, ::UINT uMsg, ::WPARAM wParam, ::LPARAM lParam);
   int onDestroy();
-
+  int onTimerEvent(::WPARAM wParam);
   std::shared_ptr<Clap::Plugin> m_clapPlugin;
   const clap_plugin_t* m_plugin;
   const clap_plugin_gui_t* m_pluginGui;
   const clap_plugin_state_t* m_pluginState;
   freeaudio::clap_wrapper::standalone::StandaloneHost* m_standaloneHost;
   std::vector<COMDLG_FILTERSPEC> m_fileTypes{{L"clapwrapper", L"*.clapwrapper"}};
+  bool m_isTimerRunning{false};
 
   // SettingsWindow m_settingsWindow;
   wil::unique_hwnd m_hWnd;