Implement open and select file in file manager [Linux]

Only few file managers are able to select files when started from the
command line.

xdg-mime is required to retrieve the default file manager. If it's not
available or the file manager is not able to automatically select files,
the containing directory will be opened as usual.

src/properties/propertieswidget.cpp

@@ -452,7 +452,7 @@ void PropertiesWidget::openFolder(const QModelIndex &index, bool containing_fold
   if (path_items.isEmpty())
     return;
 
-#ifndef Q_OS_WIN
+#if !(defined(Q_OS_WIN) || (defined(Q_OS_UNIX) && !defined(Q_OS_MAC)))
   if (containing_folder)
     path_items.removeLast();
 #endif
@@ -470,6 +470,22 @@ void PropertiesWidget::openFolder(const QModelIndex &index, bool containing_fold
     // Dir separators MUST be win-style slashes
     QProcess::startDetached("explorer.exe", QStringList() << "/select," << fsutils::toNativePath(file_path));
   } else {
+#elif defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+  if (containing_folder) {
+    QProcess proc;
+    QString output;
+    proc.start("xdg-mime", QStringList() << "query" << "default" << "inode/directory");
+    proc.waitForFinished();
+    output = proc.readLine().simplified();
+    if (output == "dolphin.desktop")
+      proc.startDetached("dolphin", QStringList() << "--select" << fsutils::toNativePath(file_path));
+    else if (output == "nautilus-folder-handler.desktop")
+      proc.startDetached("nautilus", QStringList() << "--no-desktop" << fsutils::toNativePath(file_path));
+    else if (output == "kfmclient_dir.desktop")
+      proc.startDetached("konqueror", QStringList() << "--select" << fsutils::toNativePath(file_path));
+    else
+      QDesktopServices::openUrl(QUrl::fromLocalFile(QFileInfo(file_path).absolutePath()));
+  } else {
 #endif
     if (QFile::exists(file_path)) {
       // Hack to access samba shares with QDesktopServices::openUrl
@@ -480,7 +496,7 @@ void PropertiesWidget::openFolder(const QModelIndex &index, bool containing_fold
     } else {
       QMessageBox::warning(this, tr("I/O Error"), tr("This folder does not exist yet."));
     }
-#ifdef Q_OS_WIN
+#if defined(Q_OS_WIN) || (defined(Q_OS_UNIX) && !defined(Q_OS_MAC))
   }
 #endif
 }