Drag-and-drop checks file extensions first for plug-in candidates...

... Avoids big delays in drag-and-drop importation caused by
765ca0c8136134a1d65bfad0ea39682a83d3d984

include/audacity/ModuleInterface.h

@@ -87,12 +87,15 @@ public:
    // DiscoverPluginsAtPath() have module-specific meaning.
    // They are not necessarily file system paths to existent files that
    // could be placed in any folder and queried for
-   // plugin information.  This function returns true when that is the case.
+   // plugin information.
-   virtual bool PathsAreFiles() = 0;
+   // This function returns nonempty only when that is the case, and lists
+   // the possible extensions of such files (an empty string in a nonempty
+   // array means any file is a candidate).
+   virtual wxArrayString FileExtensions() = 0;
 
    // Returns empty, or else, where to copy a plug-in file or bundle.
-   // Drag-and-drop is supported only if PathsAreFiles() is true and this
+   // Drag-and-drop is supported only if FileExtensions() returns nonempty and
-   // function returns nonempty.
+   // this function returns nonempty.
    virtual wxString InstallPath() = 0;
 
    // Modules providing a single or static set of plugins may use

src/PluginManager.cpp

@@ -1750,6 +1750,7 @@ void PluginManager::Terminate()
 bool PluginManager::DropFile(const wxString &fileName)
 {
    auto &mm = ModuleManager::Get();
+   const wxFileName src{ fileName };
 
    for (const PluginDescriptor *plug = GetFirstPlugin(PluginTypeModule);
         plug;
@@ -1758,7 +1759,9 @@ bool PluginManager::DropFile(const wxString &fileName)
       auto module = static_cast<ModuleInterface *>
          (mm.CreateProviderInstance(plug->GetID(), plug->GetPath()));
       const auto &ff = module->InstallPath();
-      if (!ff.empty() && module->PathsAreFiles()) {
+      auto extensions = module->FileExtensions();
+      if (!ff.empty() &&
+          make_iterator_range(extensions).contains(src.GetExt())) {
          wxString errMsg;
          // Do dry-run test of the file format
          unsigned nPlugIns =
@@ -1770,7 +1773,6 @@ bool PluginManager::DropFile(const wxString &fileName)
             // actions should not be tried.
 
             // Find path to copy it
-            const wxFileName src{ fileName };
             wxFileName dst;
             dst.AssignDir( ff );
             dst.SetFullName( src.GetFullName() );

src/effects/LoadEffects.h

@@ -41,7 +41,7 @@ public:
    bool Initialize() override;
    void Terminate() override;
 
-   bool PathsAreFiles() override { return false; }
+   wxArrayString FileExtensions() override { return {}; }
    wxString InstallPath() override { return {}; }
 
    bool AutoRegisterPlugins(PluginManagerInterface & pm) override;

src/effects/VST/VSTEffect.cpp

@@ -351,6 +351,13 @@ void VSTEffectsModule::Terminate()
    return;
 }
 
+wxArrayString VSTEffectsModule::FileExtensions()
+{
+   static const wxString ext[] = { _T("vst") };
+   static const wxArrayString result{ sizeof(ext)/sizeof(*ext), ext };
+   return result;
+}
+
 wxString VSTEffectsModule::InstallPath()
 {
    // Not yet ready for VST drag-and-drop...

src/effects/VST/VSTEffect.h

@@ -391,7 +391,7 @@ public:
    bool Initialize() override;
    void Terminate() override;
 
-   bool PathsAreFiles() override { return true; }
+   wxArrayString FileExtensions() override;
    wxString InstallPath() override;
 
    bool AutoRegisterPlugins(PluginManagerInterface & pm) override;

src/effects/audiounits/AudioUnitEffect.cpp

@@ -140,6 +140,13 @@ wxString AudioUnitEffectsModule::GetDescription()
 // ModuleInterface implementation
 // ============================================================================
 
+wxArrayString AudioUnitEffectsModule::FileExtensions()
+{
+   static const wxString ext[] = { _T("au") };
+   static const wxArrayString result{ sizeof(ext)/sizeof(*ext), ext };
+   return result;
+}
+
 bool AudioUnitEffectsModule::Initialize()
 {
    // Nothing to do here

src/effects/audiounits/AudioUnitEffect.h

@@ -243,7 +243,7 @@ public:
    bool Initialize() override;
    void Terminate() override;
 
-   bool PathsAreFiles() override { return false; }
+   wxArrayString FileExtensions() override;
    wxString InstallPath() override { return {}; }
 
    bool AutoRegisterPlugins(PluginManagerInterface & pm) override;

src/effects/ladspa/LadspaEffect.cpp

@@ -155,6 +155,30 @@ void LadspaEffectsModule::Terminate()
    return;
 }
 
+wxArrayString LadspaEffectsModule::FileExtensions()
+{
+   static const wxString ext[] = {
+
+#ifdef __WXMSW__
+
+      { _T("dll") }
+
+#else
+
+      { _T("so") }
+
+   #ifdef __WXMAC__
+   // Is it correct that these are candidate plug-in files too for macOs?
+      , { _T("dylib") }
+   #endif
+
+#endif
+
+   };
+   static const wxArrayString result{ sizeof(ext)/sizeof(*ext), ext };
+   return result;
+}
+
 wxString LadspaEffectsModule::InstallPath()
 {
    // To do: better choice

src/effects/ladspa/LadspaEffect.h

@@ -223,7 +223,7 @@ public:
    bool Initialize() override;
    void Terminate() override;
 
-   bool PathsAreFiles() override { return true; }
+   wxArrayString FileExtensions() override;
    wxString InstallPath() override;
 
    bool AutoRegisterPlugins(PluginManagerInterface & pm) override;

src/effects/lv2/LoadLV2.h

@@ -88,7 +88,7 @@ public:
    bool Initialize() override;
    void Terminate() override;
 
-   bool PathsAreFiles() override { return false; }
+   wxArrayString FileExtensions() override { return {}; }
    wxString InstallPath() override { return {}; }
 
    bool AutoRegisterPlugins(PluginManagerInterface & pm) override;

src/effects/nyquist/LoadNyquist.cpp

@@ -160,6 +160,13 @@ void NyquistEffectsModule::Terminate()
    return;
 }
 
+wxArrayString NyquistEffectsModule::FileExtensions()
+{
+   static const wxString ext[] = { _T("ny") };
+   static const wxArrayString result{ sizeof(ext)/sizeof(*ext), ext };
+   return result;
+}
+
 wxString NyquistEffectsModule::InstallPath()
 {
    return FileNames::PlugInDir();

src/effects/nyquist/LoadNyquist.h

@@ -38,7 +38,7 @@ public:
    bool Initialize() override;
    void Terminate() override;
 
-   bool PathsAreFiles() override { return true; }
+   wxArrayString FileExtensions() override;
    wxString InstallPath() override;
 
    bool AutoRegisterPlugins(PluginManagerInterface & pm) override;

src/effects/vamp/LoadVamp.h

@@ -42,7 +42,7 @@ public:
    bool Initialize() override;
    void Terminate() override;
 
-   bool PathsAreFiles() override { return false; }
+   wxArrayString FileExtensions() override { return {}; }
    wxString InstallPath() override { return {}; }
 
    bool AutoRegisterPlugins(PluginManagerInterface & pm) override;