Action to go to specified line

src/calibre/gui2/tweak_book/boss.py

@@ -493,6 +493,14 @@ class Boss(QObject):
                      _('Saving of the book failed. Click "Show Details"'
                        ' for more information.'), det_msg=tb, show=True)
 
+    def go_to_line_number(self):
+        ed = self.gui.central.current_editor
+        if ed is None or not ed.has_line_numbers:
+            return
+        num, ok = QInputDialog.getInt(self.gui, _('Enter line number'), ('Line number:'), ed.current_line, 1, max(100000, ed.number_of_lines))
+        if ok:
+            ed.current_line = num
+
     def sync_editor_to_preview(self, name, lnum):
         editor = self.edit_file(name, 'html')
         editor.current_line = lnum
@@ -597,6 +605,7 @@ class Boss(QObject):
             actions['editor-save'].setEnabled(ed.is_modified)
             actions['editor-cut'].setEnabled(ed.copy_available)
             actions['editor-copy'].setEnabled(ed.cut_available)
+            actions['go-to-line-number'].setEnabled(ed.has_line_numbers)
             self.gui.keyboard.set_mode(ed.syntax)
             name = None
             for n, x in editors.iteritems():
@@ -607,6 +616,7 @@ class Boss(QObject):
                 self.gui.preview.show(name)
         else:
             self.gui.keyboard.set_mode('other')
+            actions['go-to-line-number'].setEnabled(False)
 
     def editor_close_requested(self, editor):
         name = None

src/calibre/gui2/tweak_book/editor/widget.py

@@ -15,6 +15,8 @@ from calibre.gui2.tweak_book.editor.text import TextEdit
 
 class Editor(QMainWindow):
 
+    has_line_numbers = True
+
     modification_state_changed = pyqtSignal(object)
     undo_redo_state_changed = pyqtSignal(object, object)
     copy_available_state_changed = pyqtSignal(object)
@@ -47,6 +49,10 @@ class Editor(QMainWindow):
             self.editor.go_to_line(val)
         return property(fget=fget, fset=fset)
 
+    @property
+    def number_of_lines(self):
+        return self.editor.blockCount()
+
     @dynamic_property
     def data(self):
         def fget(self):

src/calibre/gui2/tweak_book/ui.py

@@ -244,6 +244,7 @@ class Main(MainWindow):
         self.action_count = sreg('count-matches', _('&Count all'),
                                    'count', keys=('Ctrl+N'), description=_('Count number of matches'))
         self.action_mark = reg(None, _('&Mark selected text'), self.boss.mark_selected_text, 'mark-selected-text', ('Ctrl+Shift+M',), _('Mark selected text'))
+        self.action_go_to_line = reg(None, _('Go to &line'), self.boss.go_to_line_number, 'go-to-line-number', ('Ctrl+.',), _('Go to line number'))
 
         # Miscellaneous actions
         group = _('Miscellaneous')
@@ -302,6 +303,8 @@ class Main(MainWindow):
         a(self.action_count)
         e.addSeparator()
         a(self.action_mark)
+        e.addSeparator()
+        a(self.action_go_to_line)
 
     def create_toolbars(self):
         def create(text, name):