Fix #2035215 ['abort' copy is too abrupt](https://bugs.launchpad.net/…

…calibre/+bug/2035215)

src/calibre/gui2/__init__.py

@@ -624,10 +624,10 @@ def question_dialog(parent, title, msg, det_msg='', show_copy_button=False,
     # Set skip_dialog_msg to a message displayed to the user
     skip_dialog_name=None, skip_dialog_msg=_('Show this confirmation again'),
     skip_dialog_skipped_value=True, skip_dialog_skip_precheck=True,
-    # Override icon (QIcon to be used as the icon for this dialog or string for I())
+    # Override icon (QIcon to be used as the icon for this dialog or string for QIcon.ic())
     override_icon=None,
     # Change the text/icons of the yes and no buttons.
-    # The icons must be QIcon objects or strings for I()
+    # The icons must be QIcon objects or strings for QIcon.ic()
     yes_text=None, no_text=None, yes_icon=None, no_icon=None,
     # Add an Abort button which if clicked will cause this function to raise
     # the Aborted exception

src/calibre/gui2/actions/copy_to_library.py

@@ -460,7 +460,9 @@ def do_copy(self, ids, db, loc, delete_after, add_duplicates=False):
         aname = _('Moving to') if delete_after else _('Copying to')
         dtitle = '%s %s'%(aname, os.path.basename(loc))
         self.pd = ProgressDialog(dtitle, min=0, max=len(ids)-1,
-                parent=self.gui, cancelable=True, icon='lt.png')
+                parent=self.gui, cancelable=True, icon='lt.png', cancel_confirm_msg=_(
+                    'Aborting this operation means that only some books will be copied'
+                    ' and resuming a partial copy is not supported. Are you sure you want to abort?'))
 
         def progress(idx, title):
             self.pd.set_msg(title)

src/calibre/gui2/dialogs/progress.py

@@ -9,16 +9,17 @@
     QDialog, pyqtSignal, Qt, QVBoxLayout, QLabel, QFont, QProgressBar, QSize,
     QDialogButtonBox, QApplication, QFontMetrics, QHBoxLayout, QIcon)
 
-from calibre.gui2 import elided_text
+from calibre.gui2 import elided_text, question_dialog
 from calibre.gui2.progress_indicator import ProgressIndicator
 
 
 class ProgressDialog(QDialog):
 
     canceled_signal = pyqtSignal()
 
-    def __init__(self, title, msg='\u00a0', min=0, max=99, parent=None, cancelable=True, icon=None):
+    def __init__(self, title, msg='\u00a0', min=0, max=99, parent=None, cancelable=True, icon=None, cancel_confirm_msg=''):
         QDialog.__init__(self, parent)
+        self.cancel_confirm_msg = cancel_confirm_msg
         if icon is None:
             self.l = l = QVBoxLayout(self)
         else:
@@ -113,6 +114,12 @@ def msg(self, val):
         self.message.setText(elided_text(val, self.font(), self.message.minimumWidth()-10))
 
     def _canceled(self, *args):
+        if self.cancel_confirm_msg:
+            if not question_dialog(
+                self, _('Are you sure?'), self.cancel_confirm_msg, override_icon='dialog_warning.png',
+                yes_text=_('Yes, abort'), no_text=_('No, keep copying')
+            ):
+                return
         self.canceled = True
         self.button_box.setDisabled(True)
         self.title = _('Aborting...')