plugin: allow dropping jsfx into plugin

allow drag and drop of a jsfx file into the plugin when no plugin is loaded

plugin/editor.cpp

@@ -231,6 +231,36 @@ YsfxEditor::~YsfxEditor()
     }
 }
 
+//------------------------------------------------------------------------------
+bool YsfxEditor::isInterestedInFileDrag(const juce::StringArray &files)
+{
+    (void)files;
+
+    YsfxInfo::Ptr info = m_impl->m_info;
+    ysfx_t *fx = info->effect.get();
+
+    return !ysfx_is_compiled(fx);
+}
+
+void YsfxEditor::filesDropped(const juce::StringArray &files, int x, int y)
+{
+    (void)x;
+    (void)y;
+
+    // We only allow jsfx drops if no JSFX was loaded.
+    YsfxInfo::Ptr info = m_impl->m_info;
+    ysfx_t *fx = info->effect.get();
+
+    if (!ysfx_is_compiled(fx)) {
+        if (files.size() == 1) {
+            juce::File file{files[0]};
+            if (file.existsAsFile()) {
+                m_impl->loadFile(files[0]);
+            }   
+        }
+    }
+}
+
 void YsfxEditor::resized()
 {
     m_impl->relayoutUILater();

plugin/editor.h

@@ -20,14 +20,16 @@
 #include <memory>
 class YsfxProcessor;
 
-class YsfxEditor : public juce::AudioProcessorEditor {
+class YsfxEditor : public juce::AudioProcessorEditor, public juce::FileDragAndDropTarget {
 public:
     explicit YsfxEditor(YsfxProcessor &proc);
     ~YsfxEditor() override;
 
 protected:
     void resized() override;
     void paint (juce::Graphics& g) override;
+    bool isInterestedInFileDrag(const juce::StringArray &files) override;
+    void filesDropped(const juce::StringArray &files, int x, int y) override;
 
 private:
     void readTheme();