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@@ -1,345 +1,349 b'' | |||
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1 | 1 | # encoding: utf-8 |
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2 | 2 | """ |
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3 | 3 | Paging capabilities for IPython.core |
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4 | 4 | |
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5 | 5 | Authors: |
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6 | 6 | |
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7 | 7 | * Brian Granger |
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8 | 8 | * Fernando Perez |
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9 | 9 | |
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10 | 10 | Notes |
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11 | 11 | ----- |
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12 | 12 | |
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13 | 13 | For now this uses ipapi, so it can't be in IPython.utils. If we can get |
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14 | 14 | rid of that dependency, we could move it there. |
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15 | 15 | ----- |
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16 | 16 | """ |
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17 | 17 | |
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18 | 18 | #----------------------------------------------------------------------------- |
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19 | 19 | # Copyright (C) 2008-2011 The IPython Development Team |
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20 | 20 | # |
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21 | 21 | # Distributed under the terms of the BSD License. The full license is in |
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22 | 22 | # the file COPYING, distributed as part of this software. |
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23 | 23 | #----------------------------------------------------------------------------- |
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24 | 24 | |
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25 | 25 | #----------------------------------------------------------------------------- |
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26 | 26 | # Imports |
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27 | 27 | #----------------------------------------------------------------------------- |
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28 | 28 | from __future__ import print_function |
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29 | 29 | |
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30 | 30 | import os |
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31 | 31 | import re |
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32 | 32 | import subprocess |
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33 | 33 | import sys |
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34 | 34 | import tempfile |
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35 | 35 | |
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36 | 36 | from io import UnsupportedOperation |
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37 | 37 | |
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38 | 38 | from IPython.core import ipapi |
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39 | 39 | from IPython.core.error import TryNext |
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40 | from IPython.utils.cursesimport import use_curses | |
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41 | 40 | from IPython.utils.data import chop |
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42 | 41 | from IPython.utils import io |
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43 | 42 | from IPython.utils.process import system |
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44 | 43 | from IPython.utils.terminal import get_terminal_size |
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45 | 44 | from IPython.utils import py3compat |
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46 | 45 | |
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47 | 46 | |
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48 | 47 | #----------------------------------------------------------------------------- |
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49 | 48 | # Classes and functions |
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50 | 49 | #----------------------------------------------------------------------------- |
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51 | 50 | |
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52 | 51 | esc_re = re.compile(r"(\x1b[^m]+m)") |
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53 | 52 | |
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54 | 53 | def page_dumb(strng, start=0, screen_lines=25): |
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55 | 54 | """Very dumb 'pager' in Python, for when nothing else works. |
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56 | 55 | |
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57 | 56 | Only moves forward, same interface as page(), except for pager_cmd and |
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58 | 57 | mode.""" |
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59 | 58 | |
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60 | 59 | out_ln = strng.splitlines()[start:] |
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61 | 60 | screens = chop(out_ln,screen_lines-1) |
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62 | 61 | if len(screens) == 1: |
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63 | 62 | print(os.linesep.join(screens[0]), file=io.stdout) |
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64 | 63 | else: |
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65 | 64 | last_escape = "" |
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66 | 65 | for scr in screens[0:-1]: |
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67 | 66 | hunk = os.linesep.join(scr) |
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68 | 67 | print(last_escape + hunk, file=io.stdout) |
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69 | 68 | if not page_more(): |
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70 | 69 | return |
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71 | 70 | esc_list = esc_re.findall(hunk) |
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72 | 71 | if len(esc_list) > 0: |
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73 | 72 | last_escape = esc_list[-1] |
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74 | 73 | print(last_escape + os.linesep.join(screens[-1]), file=io.stdout) |
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75 | 74 | |
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76 |
def _detect_screen_size( |
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75 | def _detect_screen_size(screen_lines_def): | |
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77 | 76 | """Attempt to work out the number of lines on the screen. |
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78 | 77 | |
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79 | 78 | This is called by page(). It can raise an error (e.g. when run in the |
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80 | 79 | test suite), so it's separated out so it can easily be called in a try block. |
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81 | 80 | """ |
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82 | 81 | TERM = os.environ.get('TERM',None) |
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83 | if (TERM=='xterm' or TERM=='xterm-color') and sys.platform != 'sunos5': | |
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84 | local_use_curses = use_curses | |
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85 | else: | |
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82 | if not((TERM=='xterm' or TERM=='xterm-color') and sys.platform != 'sunos5'): | |
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86 | 83 | # curses causes problems on many terminals other than xterm, and |
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87 | 84 | # some termios calls lock up on Sun OS5. |
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88 | local_use_curses = False | |
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89 | if local_use_curses: | |
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85 | return screen_lines_def | |
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86 | ||
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87 | try: | |
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90 | 88 | import termios |
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91 | 89 | import curses |
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92 | # There is a bug in curses, where *sometimes* it fails to properly | |
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93 | # initialize, and then after the endwin() call is made, the | |
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94 | # terminal is left in an unusable state. Rather than trying to | |
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95 | # check everytime for this (by requesting and comparing termios | |
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96 | # flags each time), we just save the initial terminal state and | |
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97 | # unconditionally reset it every time. It's cheaper than making | |
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98 | # the checks. | |
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99 | term_flags = termios.tcgetattr(sys.stdout) | |
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100 | ||
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101 | # Curses modifies the stdout buffer size by default, which messes | |
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102 | # up Python's normal stdout buffering. This would manifest itself | |
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103 | # to IPython users as delayed printing on stdout after having used | |
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104 | # the pager. | |
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105 | # | |
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106 | # We can prevent this by manually setting the NCURSES_NO_SETBUF | |
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107 | # environment variable. For more details, see: | |
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108 | # http://bugs.python.org/issue10144 | |
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109 | NCURSES_NO_SETBUF = os.environ.get('NCURSES_NO_SETBUF', None) | |
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110 | os.environ['NCURSES_NO_SETBUF'] = '' | |
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111 | ||
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112 | # Proceed with curses initialization | |
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90 | except ImportError: | |
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91 | return screen_lines_def | |
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92 | ||
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93 | # There is a bug in curses, where *sometimes* it fails to properly | |
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94 | # initialize, and then after the endwin() call is made, the | |
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95 | # terminal is left in an unusable state. Rather than trying to | |
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96 | # check everytime for this (by requesting and comparing termios | |
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97 | # flags each time), we just save the initial terminal state and | |
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98 | # unconditionally reset it every time. It's cheaper than making | |
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99 | # the checks. | |
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100 | term_flags = termios.tcgetattr(sys.stdout) | |
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101 | ||
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102 | # Curses modifies the stdout buffer size by default, which messes | |
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103 | # up Python's normal stdout buffering. This would manifest itself | |
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104 | # to IPython users as delayed printing on stdout after having used | |
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105 | # the pager. | |
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106 | # | |
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107 | # We can prevent this by manually setting the NCURSES_NO_SETBUF | |
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108 | # environment variable. For more details, see: | |
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109 | # http://bugs.python.org/issue10144 | |
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110 | NCURSES_NO_SETBUF = os.environ.get('NCURSES_NO_SETBUF', None) | |
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111 | os.environ['NCURSES_NO_SETBUF'] = '' | |
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112 | ||
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113 | # Proceed with curses initialization | |
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114 | try: | |
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113 | 115 | scr = curses.initscr() |
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114 | screen_lines_real,screen_cols = scr.getmaxyx() | |
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115 | curses.endwin() | |
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116 | except AttributeError: | |
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117 | # Curses on Solaris may not be complete, so we can't use it there | |
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118 | return screen_lines_def | |
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119 | ||
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120 | screen_lines_real,screen_cols = scr.getmaxyx() | |
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121 | curses.endwin() | |
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116 | 122 | |
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117 |
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118 |
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119 |
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120 | else: | |
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121 | os.environ['NCURSES_NO_SETBUF'] = NCURSES_NO_SETBUF | |
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122 | ||
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123 | # Restore terminal state in case endwin() didn't. | |
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124 | termios.tcsetattr(sys.stdout,termios.TCSANOW,term_flags) | |
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125 | # Now we have what we needed: the screen size in rows/columns | |
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126 | return screen_lines_real | |
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127 | #print '***Screen size:',screen_lines_real,'lines x',\ | |
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128 | #screen_cols,'columns.' # dbg | |
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123 | # Restore environment | |
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124 | if NCURSES_NO_SETBUF is None: | |
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125 | del os.environ['NCURSES_NO_SETBUF'] | |
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129 | 126 | else: |
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130 | return screen_lines_def | |
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127 | os.environ['NCURSES_NO_SETBUF'] = NCURSES_NO_SETBUF | |
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128 | ||
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129 | # Restore terminal state in case endwin() didn't. | |
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130 | termios.tcsetattr(sys.stdout,termios.TCSANOW,term_flags) | |
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131 | # Now we have what we needed: the screen size in rows/columns | |
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132 | return screen_lines_real | |
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133 | #print '***Screen size:',screen_lines_real,'lines x',\ | |
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134 | #screen_cols,'columns.' # dbg | |
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131 | 135 | |
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132 | 136 | def page(strng, start=0, screen_lines=0, pager_cmd=None): |
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133 | 137 | """Print a string, piping through a pager after a certain length. |
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134 | 138 | |
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135 | 139 | The screen_lines parameter specifies the number of *usable* lines of your |
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136 | 140 | terminal screen (total lines minus lines you need to reserve to show other |
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137 | 141 | information). |
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138 | 142 | |
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139 | 143 | If you set screen_lines to a number <=0, page() will try to auto-determine |
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140 | 144 | your screen size and will only use up to (screen_size+screen_lines) for |
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141 | 145 | printing, paging after that. That is, if you want auto-detection but need |
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142 | 146 | to reserve the bottom 3 lines of the screen, use screen_lines = -3, and for |
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143 | 147 | auto-detection without any lines reserved simply use screen_lines = 0. |
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144 | 148 | |
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145 | 149 | If a string won't fit in the allowed lines, it is sent through the |
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146 | 150 | specified pager command. If none given, look for PAGER in the environment, |
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147 | 151 | and ultimately default to less. |
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148 | 152 | |
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149 | 153 | If no system pager works, the string is sent through a 'dumb pager' |
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150 | 154 | written in python, very simplistic. |
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151 | 155 | """ |
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152 | 156 | |
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153 | 157 | # Some routines may auto-compute start offsets incorrectly and pass a |
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154 | 158 | # negative value. Offset to 0 for robustness. |
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155 | 159 | start = max(0, start) |
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156 | 160 | |
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157 | 161 | # first, try the hook |
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158 | 162 | ip = ipapi.get() |
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159 | 163 | if ip: |
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160 | 164 | try: |
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161 | 165 | ip.hooks.show_in_pager(strng) |
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162 | 166 | return |
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163 | 167 | except TryNext: |
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164 | 168 | pass |
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165 | 169 | |
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166 | 170 | # Ugly kludge, but calling curses.initscr() flat out crashes in emacs |
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167 | 171 | TERM = os.environ.get('TERM','dumb') |
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168 | 172 | if TERM in ['dumb','emacs'] and os.name != 'nt': |
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169 | 173 | print(strng) |
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170 | 174 | return |
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171 | 175 | # chop off the topmost part of the string we don't want to see |
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172 | 176 | str_lines = strng.splitlines()[start:] |
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173 | 177 | str_toprint = os.linesep.join(str_lines) |
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174 | 178 | num_newlines = len(str_lines) |
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175 | 179 | len_str = len(str_toprint) |
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176 | 180 | |
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177 | 181 | # Dumb heuristics to guesstimate number of on-screen lines the string |
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178 | 182 | # takes. Very basic, but good enough for docstrings in reasonable |
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179 | 183 | # terminals. If someone later feels like refining it, it's not hard. |
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180 | 184 | numlines = max(num_newlines,int(len_str/80)+1) |
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181 | 185 | |
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182 | 186 | screen_lines_def = get_terminal_size()[1] |
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183 | 187 | |
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184 | 188 | # auto-determine screen size |
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185 | 189 | if screen_lines <= 0: |
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186 | 190 | try: |
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187 |
screen_lines += _detect_screen_size( |
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191 | screen_lines += _detect_screen_size(screen_lines_def) | |
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188 | 192 | except (TypeError, UnsupportedOperation): |
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189 | 193 | print(str_toprint, file=io.stdout) |
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190 | 194 | return |
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191 | 195 | |
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192 | 196 | #print 'numlines',numlines,'screenlines',screen_lines # dbg |
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193 | 197 | if numlines <= screen_lines : |
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194 | 198 | #print '*** normal print' # dbg |
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195 | 199 | print(str_toprint, file=io.stdout) |
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196 | 200 | else: |
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197 | 201 | # Try to open pager and default to internal one if that fails. |
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198 | 202 | # All failure modes are tagged as 'retval=1', to match the return |
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199 | 203 | # value of a failed system command. If any intermediate attempt |
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200 | 204 | # sets retval to 1, at the end we resort to our own page_dumb() pager. |
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201 | 205 | pager_cmd = get_pager_cmd(pager_cmd) |
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202 | 206 | pager_cmd += ' ' + get_pager_start(pager_cmd,start) |
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203 | 207 | if os.name == 'nt': |
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204 | 208 | if pager_cmd.startswith('type'): |
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205 | 209 | # The default WinXP 'type' command is failing on complex strings. |
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206 | 210 | retval = 1 |
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207 | 211 | else: |
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208 | 212 | tmpname = tempfile.mktemp('.txt') |
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209 | 213 | tmpfile = open(tmpname,'wt') |
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210 | 214 | tmpfile.write(strng) |
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211 | 215 | tmpfile.close() |
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212 | 216 | cmd = "%s < %s" % (pager_cmd,tmpname) |
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213 | 217 | if os.system(cmd): |
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214 | 218 | retval = 1 |
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215 | 219 | else: |
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216 | 220 | retval = None |
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217 | 221 | os.remove(tmpname) |
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218 | 222 | else: |
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219 | 223 | try: |
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220 | 224 | retval = None |
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221 | 225 | # if I use popen4, things hang. No idea why. |
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222 | 226 | #pager,shell_out = os.popen4(pager_cmd) |
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223 | 227 | pager = os.popen(pager_cmd, 'w') |
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224 | 228 | try: |
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225 | 229 | pager_encoding = pager.encoding or sys.stdout.encoding |
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226 | 230 | pager.write(py3compat.cast_bytes_py2( |
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227 | 231 | strng, encoding=pager_encoding)) |
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228 | 232 | finally: |
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229 | 233 | retval = pager.close() |
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230 | 234 | except IOError as msg: # broken pipe when user quits |
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231 | 235 | if msg.args == (32, 'Broken pipe'): |
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232 | 236 | retval = None |
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233 | 237 | else: |
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234 | 238 | retval = 1 |
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235 | 239 | except OSError: |
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236 | 240 | # Other strange problems, sometimes seen in Win2k/cygwin |
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237 | 241 | retval = 1 |
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238 | 242 | if retval is not None: |
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239 | 243 | page_dumb(strng,screen_lines=screen_lines) |
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240 | 244 | |
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241 | 245 | |
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242 | 246 | def page_file(fname, start=0, pager_cmd=None): |
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243 | 247 | """Page a file, using an optional pager command and starting line. |
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244 | 248 | """ |
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245 | 249 | |
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246 | 250 | pager_cmd = get_pager_cmd(pager_cmd) |
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247 | 251 | pager_cmd += ' ' + get_pager_start(pager_cmd,start) |
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248 | 252 | |
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249 | 253 | try: |
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250 | 254 | if os.environ['TERM'] in ['emacs','dumb']: |
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251 | 255 | raise EnvironmentError |
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252 | 256 | system(pager_cmd + ' ' + fname) |
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253 | 257 | except: |
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254 | 258 | try: |
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255 | 259 | if start > 0: |
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256 | 260 | start -= 1 |
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257 | 261 | page(open(fname).read(),start) |
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258 | 262 | except: |
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259 | 263 | print('Unable to show file',repr(fname)) |
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260 | 264 | |
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261 | 265 | |
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262 | 266 | def get_pager_cmd(pager_cmd=None): |
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263 | 267 | """Return a pager command. |
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264 | 268 | |
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265 | 269 | Makes some attempts at finding an OS-correct one. |
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266 | 270 | """ |
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267 | 271 | if os.name == 'posix': |
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268 | 272 | default_pager_cmd = 'less -r' # -r for color control sequences |
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269 | 273 | elif os.name in ['nt','dos']: |
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270 | 274 | default_pager_cmd = 'type' |
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271 | 275 | |
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272 | 276 | if pager_cmd is None: |
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273 | 277 | try: |
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274 | 278 | pager_cmd = os.environ['PAGER'] |
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275 | 279 | except: |
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276 | 280 | pager_cmd = default_pager_cmd |
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277 | 281 | return pager_cmd |
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278 | 282 | |
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279 | 283 | |
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280 | 284 | def get_pager_start(pager, start): |
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281 | 285 | """Return the string for paging files with an offset. |
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282 | 286 | |
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283 | 287 | This is the '+N' argument which less and more (under Unix) accept. |
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284 | 288 | """ |
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285 | 289 | |
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286 | 290 | if pager in ['less','more']: |
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287 | 291 | if start: |
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288 | 292 | start_string = '+' + str(start) |
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289 | 293 | else: |
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290 | 294 | start_string = '' |
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291 | 295 | else: |
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292 | 296 | start_string = '' |
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293 | 297 | return start_string |
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294 | 298 | |
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295 | 299 | |
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296 | 300 | # (X)emacs on win32 doesn't like to be bypassed with msvcrt.getch() |
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297 | 301 | if os.name == 'nt' and os.environ.get('TERM','dumb') != 'emacs': |
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298 | 302 | import msvcrt |
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299 | 303 | def page_more(): |
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300 | 304 | """ Smart pausing between pages |
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301 | 305 | |
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302 | 306 | @return: True if need print more lines, False if quit |
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303 | 307 | """ |
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304 | 308 | io.stdout.write('---Return to continue, q to quit--- ') |
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305 | 309 | ans = msvcrt.getch() |
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306 | 310 | if ans in ("q", "Q"): |
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307 | 311 | result = False |
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308 | 312 | else: |
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309 | 313 | result = True |
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310 | 314 | io.stdout.write("\b"*37 + " "*37 + "\b"*37) |
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311 | 315 | return result |
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312 | 316 | else: |
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313 | 317 | def page_more(): |
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314 | 318 | ans = raw_input('---Return to continue, q to quit--- ') |
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315 | 319 | if ans.lower().startswith('q'): |
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316 | 320 | return False |
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317 | 321 | else: |
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318 | 322 | return True |
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319 | 323 | |
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320 | 324 | |
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321 | 325 | def snip_print(str,width = 75,print_full = 0,header = ''): |
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322 | 326 | """Print a string snipping the midsection to fit in width. |
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323 | 327 | |
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324 | 328 | print_full: mode control: |
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325 | 329 | - 0: only snip long strings |
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326 | 330 | - 1: send to page() directly. |
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327 | 331 | - 2: snip long strings and ask for full length viewing with page() |
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328 | 332 | Return 1 if snipping was necessary, 0 otherwise.""" |
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329 | 333 | |
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330 | 334 | if print_full == 1: |
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331 | 335 | page(header+str) |
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332 | 336 | return 0 |
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333 | 337 | |
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334 | 338 | print(header, end=' ') |
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335 | 339 | if len(str) < width: |
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336 | 340 | print(str) |
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337 | 341 | snip = 0 |
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338 | 342 | else: |
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339 | 343 | whalf = int((width -5)/2) |
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340 | 344 | print(str[:whalf] + ' <...> ' + str[-whalf:]) |
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341 | 345 | snip = 1 |
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342 | 346 | if snip and print_full == 2: |
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343 | 347 | if raw_input(header+' Snipped. View (y/n)? [N]').lower() == 'y': |
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344 | 348 | page(str) |
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345 | 349 | return snip |
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1 | NO CONTENT: file was removed |
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