add option to open containing folder

gui/griffon-app/controllers/com/muwire/gui/MainFrameController.groovy

@@ -11,6 +11,7 @@ import net.i2p.crypto.DSAEngine
 import net.i2p.data.Base64
 import net.i2p.data.Signature
 
+import java.awt.Desktop
 import java.awt.event.ActionEvent
 import java.nio.charset.StandardCharsets
 
@@ -383,7 +384,7 @@ class MainFrameController {
     @ControllerAction
     void showFileDetails() {
         def selected = view.selectedSharedFiles()
-        if (selected.size() != 1) {
+        if (selected == null || selected.size() != 1) {
             JOptionPane.showMessageDialog(null, "Please select only one file to view it's details")
             return
         }
@@ -392,6 +393,19 @@ class MainFrameController {
         params['core'] = core
         mvcGroup.createMVCGroup("shared-file", params)
     }
+    
+    @ControllerAction
+    void openContainingFolder() {
+        def selected = view.selectedSharedFiles()
+        if (selected == null || selected.size() != 1) {
+            JOptionPane.showMessageDialog(null, "Please select only one file to open it's containing folder")
+            return
+        }
+        
+        try {
+            Desktop.getDesktop().open(selected[0].file.getParentFile())
+        } catch (Exception ignored) {}
+    }
 
     void saveMuWireSettings() {
         core.saveMuSettings()

gui/griffon-app/views/com/muwire/gui/MainFrameView.groovy

@@ -608,6 +608,9 @@ class MainFrameView {
         JMenuItem certifySelectedFiles = new JMenuItem("Certify selected files")
         certifySelectedFiles.addActionListener({mvcGroup.controller.issueCertificate()})
         sharedFilesMenu.add(certifySelectedFiles)
+        JMenuItem openContainingFolder = new JMenuItem("Open containing folder")
+        openContainingFolder.addActionListener({mvcGroup.controller.openContainingFolder()})
+        sharedFilesMenu.add(openContainingFolder)
         JMenuItem showFileDetails = new JMenuItem("Show file details")
         showFileDetails.addActionListener({mvcGroup.controller.showFileDetails()})
         sharedFilesMenu.add(showFileDetails)