Provide virtual Partition::get_filesystem_string() method (#774818)

Provide and use a single interface for getting the file system string
for display, regardless of whether the partition is encrypted or the
encryption mapping is active or not.

Example return values for get_filesystem_string() for different types
and states of Partition objects:
1)  Plain ext4 file system:          -> "ext4"
2)  Closed encrypted:                -> "[Encrypted]"
3)  Open encrypted ext4 file system: -> "[Encrypted] ext4"

This simplifies the code in TreeView_Detail::create_row() which sets the
file system type displayed in the main window.  The same method will
then also be used when setting the operation description as each
operation is updated to handle encrypted file systems.

Bug 774818 - Implement LUKS read-write actions NOT requiring a
             passphrase

include/Partition.h

@@ -135,6 +135,9 @@ public:
 	// file system.  Will be overridden in derived PartitionLUKS.
 	virtual const Partition & get_filesystem_partition() const     { return *this; };
 
+	virtual const Glib::ustring get_filesystem_string() const
+	                                { return Utils::get_filesystem_string( filesystem ); };
+
 	bool operator==( const Partition & partition ) const ;
 	bool operator!=( const Partition & partition ) const ;
 		

include/PartitionLUKS.h

@@ -54,6 +54,8 @@ public:
 
 	virtual const Partition & get_filesystem_partition() const;
 
+	virtual const Glib::ustring get_filesystem_string() const;
+
 private:
 	Partition encrypted;
 	Sector header_size;  // Size of the LUKS header (everything up to the start of the mapping)

src/PartitionLUKS.cc

@@ -200,4 +200,13 @@ const Partition & PartitionLUKS::get_filesystem_partition() const
 	return *this;
 }
 
+const Glib::ustring PartitionLUKS::get_filesystem_string() const
+{
+	/* TO TRANSLATORS: means that this is an encrypted file system */
+	Glib::ustring fs_str = "[" + Glib::ustring( _("Encrypted") ) + "]";
+	if ( busy )
+		fs_str += " " + Utils::get_filesystem_string( encrypted.filesystem );
+	return fs_str;
+}
+
 } //GParted

src/TreeView_Detail.cc

@@ -184,21 +184,7 @@ void TreeView_Detail::create_row( const Gtk::TreeRow & treerow,
 
 	// file system
 	treerow[treeview_detail_columns.color] = Utils::get_color_as_pixbuf( filesystem_ptn.filesystem, 16, 16 );
-	if ( partition.filesystem == FS_LUKS && partition.busy )
+	treerow[treeview_detail_columns.filesystem] = partition.get_filesystem_string();
-	{
-		const Partition & encrypted = dynamic_cast<const PartitionLUKS *>( &partition )->get_encrypted();
-		/* TO TRANSLATORS: means that this is an encrypted file system */
-		treerow[treeview_detail_columns.filesystem] = "[" + Glib::ustring( _("Encrypted") ) + "] " +
-		                                              Utils::get_filesystem_string( encrypted.filesystem );
-	}
-	else if ( partition.filesystem == FS_LUKS && ! partition.busy )
-	{
-		treerow[treeview_detail_columns.filesystem] = "[" + Glib::ustring( _("Encrypted") ) + "]";
-	}
-	else
-	{
-		treerow[treeview_detail_columns.filesystem] = Utils::get_filesystem_string( partition.filesystem );
-	}
 
 	// mount point
 	std::vector<Glib::ustring> temp_mountpoints = filesystem_ptn.get_mountpoints();