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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 | import os | |
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20 | import signal | |
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21 | import time | |
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22 | import threading | |
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23 | ||
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19 | 24 | from IPython.core.interactiveshell import InteractiveShell |
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20 | 25 | from IPython.external.qt_for_kernel import QtCore, QtGui |
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21 | 26 | from IPython.lib.inputhook import allow_CTRL_C, ignore_CTRL_C, stdin_ready |
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22 | 27 | |
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23 | 28 | #----------------------------------------------------------------------------- |
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24 | 29 | # Code |
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25 | 30 | #----------------------------------------------------------------------------- |
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26 | 31 | |
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27 | 32 | def create_inputhook_qt4(mgr, app=None): |
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28 | 33 | """Create an input hook for running the Qt4 application event loop. |
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29 | 34 | |
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30 | 35 | Parameters |
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31 | 36 | ---------- |
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32 | 37 | mgr : an InputHookManager |
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33 | 38 | |
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34 | 39 | app : Qt Application, optional. |
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35 | 40 | Running application to use. If not given, we probe Qt for an |
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36 | 41 | existing application object, and create a new one if none is found. |
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37 | 42 | |
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38 | 43 | Returns |
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39 | 44 | ------- |
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40 | 45 | A pair consisting of a Qt Application (either the one given or the |
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41 | 46 | one found or created) and a inputhook. |
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42 | 47 | |
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43 | 48 | Notes |
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44 | 49 | ----- |
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45 | 50 | We use a custom input hook instead of PyQt4's default one, as it |
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46 | 51 | interacts better with the readline packages (issue #481). |
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47 | 52 | |
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48 | 53 | The inputhook function works in tandem with a 'pre_prompt_hook' |
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49 | 54 | which automatically restores the hook as an inputhook in case the |
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50 | 55 | latter has been temporarily disabled after having intercepted a |
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51 | 56 | KeyboardInterrupt. |
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52 | 57 | """ |
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53 | 58 | |
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54 | 59 | if app is None: |
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55 | 60 | app = QtCore.QCoreApplication.instance() |
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56 | 61 | if app is None: |
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57 | 62 | app = QtGui.QApplication([" "]) |
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58 | 63 | |
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59 | 64 | # Re-use previously created inputhook if any |
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60 | 65 | ip = InteractiveShell.instance() |
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61 | 66 | if hasattr(ip, '_inputhook_qt4'): |
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62 | 67 | return app, ip._inputhook_qt4 |
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63 | 68 | |
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64 | 69 | # Otherwise create the inputhook_qt4/preprompthook_qt4 pair of |
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65 | 70 | # hooks (they both share the got_kbdint flag) |
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66 | 71 | |
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67 | 72 | got_kbdint = [False] |
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68 | 73 | |
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69 | 74 | def inputhook_qt4(): |
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70 | 75 | """PyOS_InputHook python hook for Qt4. |
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71 | 76 | |
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72 | 77 | Process pending Qt events and if there's no pending keyboard |
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73 | 78 | input, spend a short slice of time (50ms) running the Qt event |
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74 | 79 | loop. |
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75 | 80 | |
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76 | 81 | As a Python ctypes callback can't raise an exception, we catch |
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77 | 82 | the KeyboardInterrupt and temporarily deactivate the hook, |
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78 | 83 | which will let a *second* CTRL+C be processed normally and go |
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79 | 84 | back to a clean prompt line. |
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80 | 85 | """ |
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81 | 86 | try: |
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82 | 87 | allow_CTRL_C() |
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83 | 88 | app = QtCore.QCoreApplication.instance() |
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84 | 89 | if not app: # shouldn't happen, but safer if it happens anyway... |
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85 | 90 | return 0 |
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86 | 91 | app.processEvents(QtCore.QEventLoop.AllEvents, 300) |
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87 | 92 | if not stdin_ready(): |
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88 | 93 | # Generally a program would run QCoreApplication::exec() |
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89 | 94 | # from main() to enter and process the Qt event loop until |
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90 | 95 | # quit() or exit() is called and the program terminates. |
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91 | 96 | # |
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92 | 97 | # For our input hook integration, we need to repeatedly |
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93 | 98 | # enter and process the Qt event loop for only a short |
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94 | 99 | # amount of time (say 50ms) to ensure that Python stays |
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95 | 100 | # responsive to other user inputs. |
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96 | 101 | # |
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97 | 102 | # A naive approach would be to repeatedly call |
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98 | 103 | # QCoreApplication::exec(), using a timer to quit after a |
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99 | 104 | # short amount of time. Unfortunately, QCoreApplication |
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100 | 105 | # emits an aboutToQuit signal before stopping, which has |
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101 | 106 | # the undesirable effect of closing all modal windows. |
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102 | 107 | # |
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103 | 108 | # To work around this problem, we instead create a |
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104 | 109 | # QEventLoop and call QEventLoop::exec(). Other than |
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105 | 110 | # setting some state variables which do not seem to be |
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106 | 111 | # used anywhere, the only thing QCoreApplication adds is |
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107 | 112 | # the aboutToQuit signal which is precisely what we are |
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108 | 113 | # trying to avoid. |
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109 | 114 | timer = QtCore.QTimer() |
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110 | 115 | event_loop = QtCore.QEventLoop() |
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111 | 116 | timer.timeout.connect(event_loop.quit) |
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112 | 117 | while not stdin_ready(): |
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113 | 118 | timer.start(50) |
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114 | 119 | event_loop.exec_() |
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115 | 120 | timer.stop() |
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116 | 121 | except KeyboardInterrupt: |
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117 | 122 | ignore_CTRL_C() |
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118 | 123 | got_kbdint[0] = True |
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119 | 124 | mgr.clear_inputhook() |
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120 | import os, signal, time, threading | |
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121 | 125 | if(os.name == 'posix'): |
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122 | 126 | pid = os.getpid() |
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123 | 127 | print("^C") |
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124 | 128 | thread = threading.Thread( |
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125 | 129 | target = lambda: |
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126 | ( time.sleep(.1), | |
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130 | ( time.sleep(.01), | |
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127 | 131 | os.kill(pid, signal.SIGINT) ) |
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128 | 132 | ) |
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129 | 133 | |
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130 | 134 | thread.start() |
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131 | 135 | else: |
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132 | 136 | print("\nKeyboardInterrupt - Ctrl-C again for new prompt") |
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133 | 137 | |
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134 | 138 | |
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135 | 139 | except: # NO exceptions are allowed to escape from a ctypes callback |
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136 | 140 | ignore_CTRL_C() |
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137 | 141 | from traceback import print_exc |
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138 | 142 | print_exc() |
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139 | 143 | print("Got exception from inputhook_qt4, unregistering.") |
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140 | 144 | mgr.clear_inputhook() |
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141 | 145 | finally: |
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142 | 146 | allow_CTRL_C() |
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143 | 147 | return 0 |
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144 | 148 | |
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145 | 149 | def preprompthook_qt4(ishell): |
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146 | 150 | """'pre_prompt_hook' used to restore the Qt4 input hook |
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147 | 151 | |
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148 | 152 | (in case the latter was temporarily deactivated after a |
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149 | 153 | CTRL+C) |
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150 | 154 | """ |
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151 | 155 | if got_kbdint[0]: |
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152 | 156 | mgr.set_inputhook(inputhook_qt4) |
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153 | 157 | got_kbdint[0] = False |
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154 | 158 | |
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155 | 159 | ip._inputhook_qt4 = inputhook_qt4 |
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156 | 160 | ip.set_hook('pre_prompt_hook', preprompthook_qt4) |
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157 | 161 | |
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158 | 162 | return app, inputhook_qt4 |
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