More work on the new viewer

src/calibre/gui2/viewer2/main.py

@@ -158,11 +158,13 @@ def main(args=sys.argv):
     app.setWindowIcon(QIcon(I('viewer.png')))
     main = EbookViewer()
     main.set_exception_handler()
+    if args:
+        acc.events.append(args[-1])
     acc.got_file.connect(main.handle_commandline_arg)
     main.show()
     main.msg_from_anotherinstance.connect(main.another_instance_wants_to_talk, type=Qt.QueuedConnection)
     if listener is not None:
-        t = Thread(name='ListenSI', target=listen, args=(listener, main.msg_from_anotherinstance))
+        t = Thread(name='ConnListener', target=listen, args=(listener, main.msg_from_anotherinstance))
         t.daemon = True
         t.start()
     QTimer.singleShot(0, acc.flush)

src/calibre/gui2/viewer2/ui.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python2
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import os
+
+from PyQt5.Qt import pyqtSignal
+
+from calibre.gui2.main_window import MainWindow
+
+
+class EbookViewer(MainWindow):
+
+    msg_from_anotherinstance = pyqtSignal(object)
+
+    def __init__(self):
+        MainWindow.__init__(self)
+
+    def handle_commandline_arg(self, arg):
+        if arg and os.path.isfile(arg) and os.access(arg, os.R_OK):
+            self.load_ebook(arg)
+
+    def another_instance_wants_to_talk(self, msg):
+        try:
+            path, open_at = msg
+        except Exception:
+            return
+        self.load_ebook(path, open_at=open_at)
+        self.raise_()