Uploaded Test files

venv/Lib/site-packages/IPython/lib/inputhookqt4.py

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+# -*- coding: utf-8 -*-
+"""
+Qt4's inputhook support function
+
+Author: Christian Boos
+"""
+
+#-----------------------------------------------------------------------------
+#  Copyright (C) 2011  The IPython Development Team
+#
+#  Distributed under the terms of the BSD License.  The full license is in
+#  the file COPYING, distributed as part of this software.
+#-----------------------------------------------------------------------------
+
+#-----------------------------------------------------------------------------
+# Imports
+#-----------------------------------------------------------------------------
+
+import os
+import signal
+import threading
+
+from IPython.core.interactiveshell import InteractiveShell
+from IPython.external.qt_for_kernel import QtCore, QtGui
+from IPython.lib.inputhook import allow_CTRL_C, ignore_CTRL_C, stdin_ready
+
+#-----------------------------------------------------------------------------
+# Module Globals
+#-----------------------------------------------------------------------------
+
+got_kbdint = False
+sigint_timer = None
+
+#-----------------------------------------------------------------------------
+# Code
+#-----------------------------------------------------------------------------
+
+def create_inputhook_qt4(mgr, app=None):
+    """Create an input hook for running the Qt4 application event loop.
+
+    Parameters
+    ----------
+    mgr : an InputHookManager
+
+    app : Qt Application, optional.
+        Running application to use.  If not given, we probe Qt for an
+        existing application object, and create a new one if none is found.
+
+    Returns
+    -------
+    A pair consisting of a Qt Application (either the one given or the
+    one found or created) and a inputhook.
+
+    Notes
+    -----
+    We use a custom input hook instead of PyQt4's default one, as it
+    interacts better with the readline packages (issue #481).
+
+    The inputhook function works in tandem with a 'pre_prompt_hook'
+    which automatically restores the hook as an inputhook in case the
+    latter has been temporarily disabled after having intercepted a
+    KeyboardInterrupt.
+    """
+
+    if app is None:
+        app = QtCore.QCoreApplication.instance()
+        if app is None:
+            app = QtGui.QApplication([" "])
+
+    # Re-use previously created inputhook if any
+    ip = InteractiveShell.instance()
+    if hasattr(ip, '_inputhook_qt4'):
+        return app, ip._inputhook_qt4
+
+    # Otherwise create the inputhook_qt4/preprompthook_qt4 pair of
+    # hooks (they both share the got_kbdint flag)
+
+    def inputhook_qt4():
+        """PyOS_InputHook python hook for Qt4.
+
+        Process pending Qt events and if there's no pending keyboard
+        input, spend a short slice of time (50ms) running the Qt event
+        loop.
+
+        As a Python ctypes callback can't raise an exception, we catch
+        the KeyboardInterrupt and temporarily deactivate the hook,
+        which will let a *second* CTRL+C be processed normally and go
+        back to a clean prompt line.
+        """
+        try:
+            allow_CTRL_C()
+            app = QtCore.QCoreApplication.instance()
+            if not app: # shouldn't happen, but safer if it happens anyway...
+                return 0
+            app.processEvents(QtCore.QEventLoop.AllEvents, 300)
+            if not stdin_ready():
+                # Generally a program would run QCoreApplication::exec()
+                # from main() to enter and process the Qt event loop until
+                # quit() or exit() is called and the program terminates.
+                #
+                # For our input hook integration, we need to repeatedly
+                # enter and process the Qt event loop for only a short
+                # amount of time (say 50ms) to ensure that Python stays
+                # responsive to other user inputs.
+                #
+                # A naive approach would be to repeatedly call
+                # QCoreApplication::exec(), using a timer to quit after a
+                # short amount of time. Unfortunately, QCoreApplication
+                # emits an aboutToQuit signal before stopping, which has
+                # the undesirable effect of closing all modal windows.
+                #
+                # To work around this problem, we instead create a
+                # QEventLoop and call QEventLoop::exec(). Other than
+                # setting some state variables which do not seem to be
+                # used anywhere, the only thing QCoreApplication adds is
+                # the aboutToQuit signal which is precisely what we are
+                # trying to avoid.
+                timer = QtCore.QTimer()
+                event_loop = QtCore.QEventLoop()
+                timer.timeout.connect(event_loop.quit)
+                while not stdin_ready():
+                    timer.start(50)
+                    event_loop.exec_()
+                    timer.stop()
+        except KeyboardInterrupt:
+            global got_kbdint, sigint_timer
+
+            ignore_CTRL_C()
+            got_kbdint = True
+            mgr.clear_inputhook()
+
+            # This generates a second SIGINT so the user doesn't have to
+            # press CTRL+C twice to get a clean prompt.
+            #
+            # Since we can't catch the resulting KeyboardInterrupt here
+            # (because this is a ctypes callback), we use a timer to
+            # generate the SIGINT after we leave this callback.
+            #
+            # Unfortunately this doesn't work on Windows (SIGINT kills
+            # Python and CTRL_C_EVENT doesn't work).
+            if(os.name == 'posix'):
+                pid = os.getpid()
+                if(not sigint_timer):
+                    sigint_timer = threading.Timer(.01, os.kill,
+                                         args=[pid, signal.SIGINT] )
+                    sigint_timer.start()
+            else:
+                print("\nKeyboardInterrupt - Ctrl-C again for new prompt")
+
+
+        except: # NO exceptions are allowed to escape from a ctypes callback
+            ignore_CTRL_C()
+            from traceback import print_exc
+            print_exc()
+            print("Got exception from inputhook_qt4, unregistering.")
+            mgr.clear_inputhook()
+        finally:
+            allow_CTRL_C()
+        return 0
+
+    def preprompthook_qt4(ishell):
+        """'pre_prompt_hook' used to restore the Qt4 input hook
+
+        (in case the latter was temporarily deactivated after a
+        CTRL+C)
+        """
+        global got_kbdint, sigint_timer
+
+        if(sigint_timer):
+            sigint_timer.cancel()
+            sigint_timer = None
+
+        if got_kbdint:
+            mgr.set_inputhook(inputhook_qt4)
+        got_kbdint = False
+
+    ip._inputhook_qt4 = inputhook_qt4
+    ip.set_hook('pre_prompt_hook', preprompthook_qt4)
+
+    return app, inputhook_qt4