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1 | 1 | # -*- coding: utf-8 -*- |
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2 | 2 | """ |
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3 | 3 | Qt4's inputhook support function |
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4 | 4 | |
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5 | 5 | Author: Christian Boos |
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6 | 6 | """ |
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7 | 7 | |
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8 | 8 | #----------------------------------------------------------------------------- |
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9 | 9 | # Copyright (C) 2011 The IPython Development Team |
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10 | 10 | # |
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11 | 11 | # Distributed under the terms of the BSD License. The full license is in |
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12 | 12 | # the file COPYING, distributed as part of this software. |
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13 | 13 | #----------------------------------------------------------------------------- |
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14 | 14 | |
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15 | 15 | #----------------------------------------------------------------------------- |
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16 | 16 | # Imports |
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17 | 17 | #----------------------------------------------------------------------------- |
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18 | 18 | |
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19 | 19 | from IPython.core import ipapi |
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20 | 20 | from IPython.external.qt_for_kernel import QtCore, QtGui |
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21 | 21 | from IPython.lib.inputhook import stdin_ready |
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22 | 22 | |
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23 | 23 | #----------------------------------------------------------------------------- |
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24 | 24 | # Code |
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25 | 25 | #----------------------------------------------------------------------------- |
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26 | 26 | |
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27 | 27 | def create_inputhook_qt4(mgr, app=None): |
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28 | 28 | """Create an input hook for running the Qt4 application event loop. |
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29 | 29 | |
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30 | 30 | Parameters |
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31 | 31 | ---------- |
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32 | 32 | mgr : an InputHookManager |
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33 | 33 | |
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34 | 34 | app : Qt Application, optional. |
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35 | 35 | Running application to use. If not given, we probe Qt for an |
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36 | 36 | existing application object, and create a new one if none is found. |
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37 | 37 | |
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38 | 38 | Returns |
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39 | 39 | ------- |
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40 | 40 | A pair consisting of a Qt Application (either the one given or the |
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41 | 41 | one found or created) and a inputhook. |
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42 | 42 | |
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43 | 43 | Notes |
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44 | 44 | ----- |
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45 | We use a custom input hook instead of PyQt4's default one, as it | |
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46 | interacts better with the readline packages (issue #481). | |
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47 | ||
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45 | 48 | The inputhook function works in tandem with a 'pre_prompt_hook' |
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46 | 49 | which automatically restores the hook as an inputhook in case the |
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47 | 50 | latter has been temporarily disabled after having intercepted a |
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48 | 51 | KeyboardInterrupt. |
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49 | 52 | """ |
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53 | ||
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50 | 54 | if app is None: |
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51 | 55 | app = QtCore.QCoreApplication.instance() |
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52 | 56 | if app is None: |
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53 | 57 | app = QtGui.QApplication([" "]) |
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54 | 58 | |
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55 | # Always use a custom input hook instead of PyQt4's default | |
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56 | # one, as it interacts better with readline packages (issue | |
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57 | # #481). | |
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59 | # Re-use previously created inputhook if any | |
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60 | ip = ipapi.get() | |
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61 | if hasattr(ip, '_inputhook_qt4'): | |
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62 | return app, ip._inputhook_qt4 | |
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58 | 63 | |
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59 | # Note that we can't let KeyboardInterrupt escape from that | |
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60 | # hook, as no exception can be raised from within a ctypes | |
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61 | # python callback. We need to make a compromise: a trapped | |
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62 | # KeyboardInterrupt will temporarily disable the input hook | |
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63 | # until we start over with a new prompt line with a second | |
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64 | # CTRL+C. | |
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64 | # Otherwise create the inputhook_qt4/preprompthook_qt4 pair of | |
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65 | # hooks (they both share the got_kbdint flag) | |
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65 | 66 | |
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66 | 67 | got_kbdint = [False] |
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67 | 68 | |
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68 | 69 | def inputhook_qt4(): |
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70 | """PyOS_InputHook python hook for Qt4. | |
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71 | ||
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72 | Process pending Qt events and if there's no pending keyboard | |
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73 | input, spend a short slice of time (50ms) running the Qt event | |
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74 | loop. | |
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75 | ||
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76 | As a Python ctypes callback can't raise an exception, we catch | |
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77 | the KeyboardInterrupt and temporarily deactivate the hook, | |
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78 | which will let a *second* CTRL+C be processed normally and go | |
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79 | back to a clean prompt line. | |
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80 | """ | |
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69 | 81 | try: |
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82 | app = QtCore.QCoreApplication.instance() | |
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70 | 83 | app.processEvents(QtCore.QEventLoop.AllEvents, 300) |
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71 | 84 | if not stdin_ready(): |
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72 | 85 | timer = QtCore.QTimer() |
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73 | 86 | timer.timeout.connect(app.quit) |
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74 | 87 | while not stdin_ready(): |
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75 | 88 | timer.start(50) |
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76 | 89 | app.exec_() |
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77 | 90 | timer.stop() |
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78 | 91 | except KeyboardInterrupt: |
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79 | 92 | got_kbdint[0] = True |
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80 | 93 | mgr.clear_inputhook() |
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81 | 94 | print("\n(event loop interrupted - " |
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82 | 95 | "hit CTRL+C again to clear the prompt)") |
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83 | 96 | return 0 |
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84 | 97 | |
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85 | 98 | def preprompthook_qt4(ishell): |
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99 | """'pre_prompt_hook' used to restore the Qt4 input hook | |
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100 | ||
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101 | (in case the latter was temporarily deactivated after a | |
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102 | CTRL+C) | |
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103 | """ | |
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86 | 104 | if got_kbdint[0]: |
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87 | 105 | mgr.set_inputhook(inputhook_qt4) |
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88 | 106 | got_kbdint[0] = False |
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89 | ipapi.get().set_hook('pre_prompt_hook', preprompthook_qt4) | |
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107 | ||
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108 | ip._inputhook_qt4 = inputhook_qt4 | |
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109 | ip.set_hook('pre_prompt_hook', preprompthook_qt4) | |
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90 | 110 | |
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91 | 111 | return app, inputhook_qt4 |
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