Allow restoring of the ORIGINAL_XXX format by right-clicking it in the book details panel

src/calibre/gui2/actions/delete.py

@@ -180,6 +180,13 @@ class DeleteAction(InterfaceAction):
                 self.gui.library_view.currentIndex())
         self.gui.tags_view.recount()
 
+    def restore_format(self, book_id, original_fmt):
+        self.gui.current_db.restore_original_format(book_id, original_fmt)
+        self.gui.library_view.model().refresh_ids([book_id])
+        self.gui.library_view.model().current_changed(self.gui.library_view.currentIndex(),
+                self.gui.library_view.currentIndex())
+        self.gui.tags_view.recount()
+
     def delete_selected_formats(self, *args):
         ids = self._get_selected_ids()
         if not ids:

src/calibre/gui2/book_details.py

@@ -405,6 +405,7 @@ class BookInfo(QWebView):
     link_clicked = pyqtSignal(object)
     remove_format = pyqtSignal(int, object)
     save_format = pyqtSignal(int, object)
+    restore_format = pyqtSignal(int, object)
 
     def __init__(self, vertical, parent=None):
         QWebView.__init__(self, parent)
@@ -418,7 +419,7 @@ class BookInfo(QWebView):
         palette.setBrush(QPalette.Base, Qt.transparent)
         self.page().setPalette(palette)
         self.css = P('templates/book_details.css', data=True).decode('utf-8')
-        for x, icon in [('remove', 'trash.png'), ('save', 'save.png')]:
+        for x, icon in [('remove', 'trash.png'), ('save', 'save.png'), ('restore', 'edit-undo.png')]:
             ac = QAction(QIcon(I(icon)), '', self)
             ac.current_fmt = None
             ac.triggered.connect(getattr(self, '%s_format_triggerred'%x))
@@ -436,6 +437,9 @@ class BookInfo(QWebView):
     def save_format_triggerred(self):
         self.context_action_triggered('save')
 
+    def restore_format_triggerred(self):
+        self.context_action_triggered('restore')
+
     def link_activated(self, link):
         self._link_clicked = True
         if unicode(link.scheme()) in ('http', 'https'):
@@ -479,7 +483,11 @@ class BookInfo(QWebView):
                 traceback.print_exc()
             else:
                 for a, t in [('remove', _('Delete the %s format')),
-                    ('save', _('Save the %s format to disk'))]:
+                    ('save', _('Save the %s format to disk')),
+                    ('restore', _('Restore the %s format')),
+                ]:
+                    if a == 'restore' and not fmt.upper().startswith('ORIGINAL_'):
+                        continue
                     ac = getattr(self, '%s_format_action'%a)
                     ac.current_fmt = (book_id, fmt)
                     ac.setText(t%parts[2])
@@ -585,6 +593,7 @@ class BookDetails(QWidget): # {{{
     view_specific_format = pyqtSignal(int, object)
     remove_specific_format = pyqtSignal(int, object)
     save_specific_format = pyqtSignal(int, object)
+    restore_specific_format = pyqtSignal(int, object)
     remote_file_dropped = pyqtSignal(object, object)
     files_dropped = pyqtSignal(object, object)
     cover_changed = pyqtSignal(object, object)
@@ -654,6 +663,7 @@ class BookDetails(QWidget): # {{{
         self.book_info.link_clicked.connect(self.handle_click)
         self.book_info.remove_format.connect(self.remove_specific_format)
         self.book_info.save_format.connect(self.save_specific_format)
+        self.book_info.restore_format.connect(self.restore_specific_format)
         self.setCursor(Qt.PointingHandCursor)
 
     def handle_click(self, link):

src/calibre/gui2/init.py

@@ -272,6 +272,8 @@ class LayoutMixin(object): # {{{
                 self.iactions['Remove Books'].remove_format_by_id)
         self.book_details.save_specific_format.connect(
                 self.iactions['Save To Disk'].save_library_format_by_ids)
+        self.book_details.restore_specific_format.connect(
+            self.iactions['Remove Books'].restore_format)
         self.book_details.view_device_book.connect(
                 self.iactions['View'].view_device_book)
 

src/calibre/library/database2.py

@@ -1541,6 +1541,14 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         opath = self.format_abspath(book_id, nfmt, index_is_id=True)
         return fmt if opath is None else nfmt
 
+    def restore_original_format(self, book_id, original_fmt, notify=True):
+        opath = self.format_abspath(book_id, original_fmt, index_is_id=True)
+        if opath is not None:
+            fmt = original_fmt.partition('_')[2]
+            with lopen(opath, 'rb') as f:
+                self.add_format(book_id, fmt, f, index_is_id=True, notify=False)
+            self.remove_format(book_id, original_fmt, index_is_id=True, notify=notify)
+
     def delete_book(self, id, notify=True, commit=True, permanent=False,
             do_clean=True):
         '''