Fix #1923094 [[Enhancement - Viewer] Open path folder](https://bugs.launchpad.net/calibre/+bug/1923094)

src/calibre/gui2/viewer/web_view.py

@@ -274,6 +274,7 @@ class ViewerBridge(Bridge):
     speak_simple_text = from_js(object)
     tts = from_js(object, object)
     edit_book = from_js(object, object, object)
+    show_book_folder = from_js()
 
     create_view = to_js()
     start_book_load = to_js()
@@ -535,6 +536,7 @@ class WebView(RestartingWebEngineView):
         self.bridge.close_prep_finished.connect(self.close_prep_finished)
         self.bridge.highlights_changed.connect(self.highlights_changed)
         self.bridge.edit_book.connect(self.edit_book)
+        self.bridge.show_book_folder.connect(self.show_book_folder)
         self.bridge.open_url.connect(safe_open_url)
         self.bridge.speak_simple_text.connect(self.tts.speak_simple_text)
         self.bridge.tts.connect(self.tts.action)
@@ -736,3 +738,7 @@ class WebView(RestartingWebEngineView):
 
     def tts_settings_changed(self, ui_settings):
         self.execute_when_ready('tts_event', 'configured', ui_settings)
+
+    def show_book_folder(self):
+        path = os.path.dirname(os.path.abspath(set_book_path.pathtoebook))
+        safe_open_url(QUrl.fromLocalFile(path))

src/pyj/read_book/overlay.pyj

@@ -787,7 +787,16 @@ class Overlay:
             if pathtoebook:
                 container.lastChild.appendChild(E.div(
                     style='margin-top: 1ex; padding-top: 1ex; border-top: solid 1px',
-                    _('Path: {}').format(pathtoebook)))
+                    _('Path:'), ' ',
+                    E.a(
+                        href='javascript: void(0)',
+                        class_='blue-link', title=_('Click to open the folder the book is in'),
+                        onclick=def():
+                            ui_operations.show_book_folder()
+                        ,
+                        pathtoebook)
+                    )
+                )
 
         book = self.view.book
         key = book.key or v'[null, 0]'

src/pyj/viewer-main.pyj

@@ -421,6 +421,8 @@ if window is window.top:
         to_python.tts(action, data or v'{}')
     ui_operations.edit_book = def (spine_name, frac, selected_text):
         to_python.edit_book(spine_name, frac, selected_text or '')
+    ui_operations.show_book_folder = def():
+        to_python.show_book_folder()
 
     document.body.appendChild(E.div(id='view'))
     window.onerror = onerror