From b0d13adba7c6dd63b3cd985ec3d364b3d3a3da78 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 8 Feb 2012 14:01:29 +0530
Subject: [PATCH] A less crash prone (I hope) implementation of
 ProceedNotification

---
 src/calibre/gui2/dialogs/message_box.py | 25 ++++++++++++-------------
 src/calibre/gui2/ui.py                  |  7 +++++++
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/src/calibre/gui2/dialogs/message_box.py b/src/calibre/gui2/dialogs/message_box.py
index 84e5569a88..3a330fe1f9 100644
--- a/src/calibre/gui2/dialogs/message_box.py
+++ b/src/calibre/gui2/dialogs/message_box.py
@@ -180,7 +180,7 @@ class ProceedNotification(MessageBox): # {{{
         self.payload = payload
         self.html_log = html_log
         self.log_viewer_title = log_viewer_title
-        self.finished.connect(self.do_proceed, type=Qt.QueuedConnection)
+        self.finished.connect(self.do_proceed)
 
         self.vlb = self.bb.addButton(_('View log'), self.bb.ActionRole)
         self.vlb.setIcon(QIcon(I('debug.png')))
@@ -195,18 +195,17 @@ class ProceedNotification(MessageBox): # {{{
                 parent=self)
 
     def do_proceed(self, result):
-        try:
-            if result == self.Accepted:
-                self.callback(self.payload)
-            elif self.cancel_callback is not None:
-                self.cancel_callback(self.payload)
-        finally:
-            # Ensure this notification is garbage collected
-            self.callback = self.cancel_callback = None
-            self.setParent(None)
-            self.finished.disconnect()
-            self.vlb.clicked.disconnect()
-            _proceed_memory.remove(self)
+        from calibre.gui2.ui import get_gui
+        func = (self.callback if result == self.Accepted else
+                self.cancel_callback)
+        gui = get_gui()
+        gui.proceed_requested.emit(func, self.payload)
+        # Ensure this notification is garbage collected
+        self.callback = self.cancel_callback = self.payload = None
+        self.setParent(None)
+        self.finished.disconnect()
+        self.vlb.clicked.disconnect()
+        _proceed_memory.remove(self)
 # }}}
 
 class ErrorNotification(MessageBox): # {{{
diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index 98fd7981c9..fa62dba4bc 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -102,10 +102,13 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin, # {{{
         ):
     'The main GUI'
 
+    proceed_requested = pyqtSignal(object, object)
 
     def __init__(self, opts, parent=None, gui_debug=None):
         global _gui
         MainWindow.__init__(self, opts, parent=parent, disable_automatic_gc=True)
+        self.proceed_requested.connect(self.do_proceed,
+                type=Qt.QueuedConnection)
         self.keyboard = Manager(self)
         _gui = self
         self.opts = opts
@@ -402,6 +405,10 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin, # {{{
         except:
             pass
 
+    def do_proceed(self, func, payload):
+        if callable(func):
+            func(payload)
+
     def no_op(self, *args):
         pass