Reimplement export plugin registation without sequence numbers

src/export/Export.cpp

@@ -282,6 +282,24 @@ BEGIN_EVENT_TABLE(Exporter, wxEvtHandler)
 END_EVENT_TABLE()
 
 namespace {
+const auto PathStart = wxT("Exporters");
+
+static Registry::GroupItem &sRegistry()
+{
+   static Registry::TransparentGroupItem<> registry{ PathStart };
+   return registry;
+}
+
+struct ExporterItem final : Registry::SingleItem {
+   ExporterItem(
+      const Identifier &id, const Exporter::ExportPluginFactory &factory )
+      : SingleItem{ id }
+      , mFactory{ factory }
+   {}
+
+   Exporter::ExportPluginFactory mFactory;
+};
+
    using ExportPluginFactories = std::vector< Exporter::ExportPluginFactory >;
    ExportPluginFactories &sFactories()
    {
@@ -291,15 +309,24 @@ namespace {
 }
 
 Exporter::RegisteredExportPlugin::RegisteredExportPlugin(
-   const ExportPluginFactory &factory )
+   const Identifier &id,
+   const ExportPluginFactory &factory,
+   const Registry::Placement &placement )
 {
    if ( factory )
-      sFactories().emplace_back( factory );
+      Registry::RegisterItem( sRegistry(), placement,
+         std::make_unique< ExporterItem >( id, factory ) );
 }
 
 Exporter::Exporter( AudacityProject &project )
 : mProject{ &project }
 {
+   using namespace Registry;
+   static OrderingPreferenceInitializer init{
+      PathStart,
+      { {wxT(""), wxT("PCM,MP3,OGG,FLAC,MP2,CommandLine,FFmpeg") } },
+   };
+
    mMixerSpec = NULL;
    mBook = NULL;
 
@@ -307,15 +334,25 @@ Exporter::Exporter( AudacityProject &project )
    for ( const auto &factory : sFactories() )
       mPlugins.emplace_back( factory() );
 
-   // The factories were pushed on the array at static initialization time in an
+   struct MyVisitor final : Visitor {
-   // unspecified sequence.  Sort according to the sequence numbers the plugins
+      MyVisitor()
-   // report to make the order determinate.
+      {
-   std::sort( mPlugins.begin(), mPlugins.end(),
+         // visit the registry to collect the plug-ins properly
-      []( const ExportPluginArray::value_type &a,
+         // sorted
-          const ExportPluginArray::value_type &b ){
+         TransparentGroupItem<> top{ PathStart };
-         return a->SequenceNumber() < b->SequenceNumber();
+         Registry::Visit( *this, &top, &sRegistry() );
       }
-   );
+
+      void Visit( SingleItem &item, const Path &path ) override
+      {
+         mPlugins.emplace_back(
+            static_cast<ExporterItem&>( item ).mFactory() );
+      }
+
+      ExportPluginArray mPlugins;
+   } visitor;
+
+   mPlugins.swap( visitor.mPlugins );
 
    SetFileDialogTitle( XO("Export Audio") );
 }

src/export/Export.h

@@ -19,6 +19,8 @@
 #include "../widgets/wxPanelWrapper.h" // to inherit
 #include "../FileNames.h" // for FileTypes
 
+#include "../commands/CommandManager.h" // for Registry::Placement
+
 class wxArrayString;
 class FileDialogWrapper;
 class wxFileCtrlEvent;
@@ -132,8 +134,6 @@ public:
                        const Tags *metadata = NULL,
                        int subformat = 0) = 0;
 
-   virtual unsigned SequenceNumber() const = 0;
-
 protected:
    std::unique_ptr<Mixer> CreateMixer(const TrackList &tracks,
          bool selectionOnly,
@@ -174,7 +174,10 @@ public:
    // to have some fresh state variables each time export begins again
    // and to compute translated strings for the current locale
    struct RegisteredExportPlugin{
-      RegisteredExportPlugin( const ExportPluginFactory& );
+      RegisteredExportPlugin(
+         const Identifier &id, // an internal string naming the plug-in
+         const ExportPluginFactory&,
+         const Registry::Placement &placement = { wxEmptyString, {} } );
    };
 
    static bool DoEditMetadata(AudacityProject &project,

src/export/ExportCL.cpp

@@ -310,8 +310,6 @@ public:
                MixerSpec *mixerSpec = NULL,
                const Tags *metadata = NULL,
                int subformat = 0) override;
-
-   virtual unsigned SequenceNumber() const override { return 60; }
 };
 
 ExportCL::ExportCL()
@@ -567,5 +565,6 @@ void ExportCL::OptionsCreate(ShuttleGui &S, int format)
    S.AddWindow( safenew ExportCLOptions{ S.GetParent(), format } );
 }
 
-static Exporter::RegisteredExportPlugin
+static Exporter::RegisteredExportPlugin sRegisteredPlugin{ "CommandLine",
-sRegisteredPlugin{ []{ return std::make_unique< ExportCL >(); } };
+   []{ return std::make_unique< ExportCL >(); }
+};

src/export/ExportFFmpeg.cpp

@@ -152,8 +152,6 @@ public:
       const Tags *metadata = NULL,
       int subformat = 0) override;
 
-   virtual unsigned SequenceNumber() const override { return 70; }
-
 private:
 
    AVOutputFormat  *   mEncFormatDesc{};       // describes our output file to libavformat
@@ -1141,8 +1139,9 @@ void ExportFFmpeg::OptionsCreate(ShuttleGui &S, int format)
    ExportPlugin::OptionsCreate(S, format);
 }
 
-static Exporter::RegisteredExportPlugin
+static Exporter::RegisteredExportPlugin sRegisteredPlugin{ "FFmpeg",
-sRegisteredPlugin{ []{ return std::make_unique< ExportFFmpeg >(); } };
+   []{ return std::make_unique< ExportFFmpeg >(); }
+};
 
 #endif
 

src/export/ExportFLAC.cpp

@@ -224,8 +224,6 @@ public:
                const Tags *metadata = NULL,
                int subformat = 0) override;
 
-   virtual unsigned SequenceNumber() const override { return 40; }
-
 private:
 
    bool GetMetadata(AudacityProject *project, const Tags *tags);
@@ -474,8 +472,9 @@ bool ExportFLAC::GetMetadata(AudacityProject *project, const Tags *tags)
    return true;
 }
 
-static Exporter::RegisteredExportPlugin
+static Exporter::RegisteredExportPlugin sRegisteredPlugin{ "FLAC",
-sRegisteredPlugin{ []{ return std::make_unique< ExportFLAC >(); } };
+   []{ return std::make_unique< ExportFLAC >(); }
+};
 
 #endif // USE_LIBFLAC
 

src/export/ExportMP2.cpp

@@ -217,8 +217,6 @@ public:
                const Tags *metadata = NULL,
                int subformat = 0) override;
 
-   virtual unsigned SequenceNumber() const override { return 50; }
-
 private:
 
    int AddTags(AudacityProject *project, ArrayOf<char> &buffer, bool *endOfFile, const Tags *tags);
@@ -498,8 +496,9 @@ void ExportMP2::AddFrame(struct id3_tag *tp, const wxString & n, const wxString
 }
 #endif
 
-static Exporter::RegisteredExportPlugin
+static Exporter::RegisteredExportPlugin sRegisteredPlugin{ "MP2",
-sRegisteredPlugin{ []{ return std::make_unique< ExportMP2 >(); } };
+   []{ return std::make_unique< ExportMP2 >(); }
+};
 
 #endif // #ifdef USE_LIBTWOLAME
 

src/export/ExportMP3.cpp

@@ -1687,8 +1687,6 @@ public:
                const Tags *metadata = NULL,
                int subformat = 0) override;
 
-   virtual unsigned SequenceNumber() const override { return 20; }
-
 private:
 
    int AskResample(int bitrate, int rate, int lowrate, int highrate);
@@ -2199,8 +2197,9 @@ void ExportMP3::AddFrame(struct id3_tag *tp, const wxString & n, const wxString
 }
 #endif
 
-static Exporter::RegisteredExportPlugin
+static Exporter::RegisteredExportPlugin sRegisteredPlugin{ "MP3",
-sRegisteredPlugin{ []{ return std::make_unique< ExportMP3 >(); } };
+   []{ return std::make_unique< ExportMP3 >(); }
+};
 
 //----------------------------------------------------------------------------
 // Return library version

src/export/ExportOGG.cpp

@@ -143,8 +143,6 @@ public:
                const Tags *metadata = NULL,
                int subformat = 0) override;
 
-   virtual unsigned SequenceNumber() const override { return 30; }
-
 private:
 
    bool FillComment(AudacityProject *project, vorbis_comment *comment, const Tags *metadata);
@@ -398,8 +396,9 @@ bool ExportOGG::FillComment(AudacityProject *project, vorbis_comment *comment, c
    return true;
 }
 
-static Exporter::RegisteredExportPlugin
+static Exporter::RegisteredExportPlugin sRegisteredPlugin{ "OGG",
-sRegisteredPlugin{ []{ return std::make_unique< ExportOGG >(); } };
+   []{ return std::make_unique< ExportOGG >(); }
+};
 
 #endif // USE_LIBVORBIS
 

src/export/ExportPCM.cpp

@@ -342,8 +342,6 @@ public:
    FileExtension GetExtension(int index) override;
    bool CheckFileName(wxFileName &filename, int format) override;
 
-   virtual unsigned SequenceNumber() const override { return 10; }
-
 private:
    void ReportTooBigError(wxWindow * pParent);
    ArrayOf<char> AdjustString(const wxString & wxStr, int sf_format);
@@ -971,5 +969,6 @@ bool ExportPCM::CheckFileName(wxFileName &filename, int format)
    return ExportPlugin::CheckFileName(filename, format);
 }
 
-static Exporter::RegisteredExportPlugin
+static Exporter::RegisteredExportPlugin sRegisteredPlugin{ "PCM",
-sRegisteredPlugin{ []{ return std::make_unique< ExportPCM >(); } };
+   []{ return std::make_unique< ExportPCM >(); }
+};