[FEATURE] Add native platform interface for opening a terminal window at

a specified path

And implement for Linux.

Add a new context menu entry to directories in browser to open a
terminal window at that directory on supported platforms

src/app/browser/qgsinbuiltdataitemproviders.cpp

@@ -175,6 +175,17 @@ void QgsAppDirectoryItemGuiProvider::populateContextMenu( QgsDataItem *item, QMe
   } );
   menu->addAction( openFolder );
 
+  if ( QgsGui::instance()->nativePlatformInterface()->capabilities() & QgsNative::NativeOpenTerminalAtPath )
+  {
+    QAction *openTerminal = new QAction( tr( "Open in Terminal…" ), menu );
+    connect( openTerminal, &QAction::triggered, this, [ = ]
+    {
+      QgsGui::instance()->nativePlatformInterface()->openTerminalAtPath( directoryItem->dirPath() );
+    } );
+    menu->addAction( openTerminal );
+    menu->addSeparator();
+  }
+
   QAction *propertiesAction = new QAction( tr( "Properties…" ), menu );
   connect( propertiesAction, &QAction::triggered, this, [ = ]
   {

src/native/linux/qgslinuxnative.cpp

@@ -23,10 +23,11 @@
 #include <QtDBus/QtDBus>
 #include <QtDebug>
 #include <QImage>
+#include <QProcess>
 
 QgsNative::Capabilities QgsLinuxNative::capabilities() const
 {
-  return NativeDesktopNotifications | NativeFilePropertiesDialog;
+  return NativeDesktopNotifications | NativeFilePropertiesDialog | NativeOpenTerminalAtPath;
 }
 
 void QgsLinuxNative::initializeMainWindow( QWindow *,
@@ -138,6 +139,38 @@ void QgsLinuxNative::setApplicationBadgeCount( int count )
   QDBusConnection::sessionBus().send( message );
 }
 
+bool QgsLinuxNative::openTerminalAtPath( const QString &path )
+{
+  // logic adapted from https://askubuntu.com/a/227669,
+  // https://github.com/Microsoft/vscode/blob/fec1775aa52e2124d3f09c7b2ac8f69c57309549/src/vs/workbench/parts/execution/electron-browser/terminal.ts
+  QString term = QStringLiteral( "xterm" );
+  const QString desktopSession = qgetenv( "DESKTOP_SESSION" );
+  const QString currentDesktop = qgetenv( "XDG_CURRENT_DESKTOP" );
+  const QString gdmSession = qgetenv( "GDMSESSION" );
+  const bool isDebian = QFile::exists( QStringLiteral( "/etc/debian_version" ) );
+  if ( isDebian )
+  {
+    term = QStringLiteral( "x-terminal-emulator" );
+  }
+  else if ( desktopSession.contains( QLatin1String( "gnome" ), Qt::CaseInsensitive ) ||
+            currentDesktop.contains( QLatin1String( "gnome" ), Qt::CaseInsensitive ) ||
+            currentDesktop.contains( QLatin1String( "unity" ), Qt::CaseInsensitive ) )
+  {
+    term = QStringLiteral( "gnome-terminal" );
+  }
+  else if ( desktopSession.contains( QLatin1String( "kde" ), Qt::CaseInsensitive ) ||
+            currentDesktop.contains( QLatin1String( "kde" ), Qt::CaseInsensitive ) ||
+            gdmSession.contains( QLatin1String( "kde" ), Qt::CaseInsensitive ) )
+  {
+    term = QStringLiteral( "konsole" );
+  }
+
+  QStringList arguments;
+  arguments << QStringLiteral( "--working-directory" )
+            << path;
+  return QProcess::startDetached( term, QStringList(), path );
+}
+
 /**
  * Automatic marshaling of a QImage for org.freedesktop.Notifications.Notify
  *

src/native/linux/qgslinuxnative.h

@@ -46,6 +46,7 @@ class NATIVE_EXPORT QgsLinuxNative : public QgsNative
     void setApplicationProgress( double progress ) override;
     void hideApplicationProgress() override;
     void setApplicationBadgeCount( int count ) override;
+    bool openTerminalAtPath( const QString &path ) override;
     NotificationResult showDesktopNotification( const QString &summary, const QString &body, const NotificationSettings &settings = NotificationSettings() ) override;
   private:
     QString mDesktopFile;

src/native/qgsnative.cpp

@@ -73,6 +73,16 @@ void QgsNative::setApplicationBadgeCount( int )
 
 }
 
+bool QgsNative::hasDarkTheme()
+{
+  return false;
+}
+
+bool QgsNative::openTerminalAtPath( const QString & )
+{
+  return false;
+}
+
 QgsNative::NotificationResult QgsNative::showDesktopNotification( const QString &, const QString &, const NotificationSettings & )
 {
   NotificationResult result;

src/native/qgsnative.h

@@ -45,6 +45,7 @@ class NATIVE_EXPORT QgsNative : public QObject
     {
       NativeDesktopNotifications = 1 << 1, //!< Native desktop notifications are supported. See showDesktopNotification().
       NativeFilePropertiesDialog = 1 << 2, //!< Platform can show a native "file" (or folder) properties dialog.
+      NativeOpenTerminalAtPath = 1 << 3, //!< Platform can open a terminal (command line) at a specific path
     };
     Q_DECLARE_FLAGS( Capabilities, Capability )
 
@@ -150,7 +151,16 @@ class NATIVE_EXPORT QgsNative : public QObject
      * Returns true if the operating system is set to utilize a "dark" theme.
      * \since QGIS 3.4
      */
-    virtual bool hasDarkTheme() {return false;}
+    virtual bool hasDarkTheme();
+
+    /**
+     * Opens a terminal (command line) window at the given \a path.
+     *
+     * This method is only supported when the interface returns the NativeOpenTerminalAtPath flag for capabilities().
+     *
+     * Returns true if terminal was successfully opened.
+     */
+    virtual bool openTerminalAtPath( const QString &path );
 
     /**
      * Notification settings, for use with showDesktopNotification().