|
|
# encoding: utf-8
|
|
|
"""
|
|
|
Paging capabilities for IPython.core
|
|
|
|
|
|
Authors:
|
|
|
|
|
|
* Brian Granger
|
|
|
* Fernando Perez
|
|
|
|
|
|
Notes
|
|
|
-----
|
|
|
|
|
|
For now this uses ipapi, so it can't be in IPython.utils. If we can get
|
|
|
rid of that dependency, we could move it there.
|
|
|
-----
|
|
|
"""
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Copyright (C) 2008-2011 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
|
|
|
#-----------------------------------------------------------------------------
|
|
|
from __future__ import print_function
|
|
|
|
|
|
import os
|
|
|
import re
|
|
|
import subprocess
|
|
|
import sys
|
|
|
import tempfile
|
|
|
|
|
|
from io import UnsupportedOperation
|
|
|
|
|
|
from IPython.core import ipapi
|
|
|
from IPython.core.error import TryNext
|
|
|
from IPython.utils.cursesimport import use_curses
|
|
|
from IPython.utils.data import chop
|
|
|
from IPython.utils import io
|
|
|
from IPython.utils.process import system
|
|
|
from IPython.utils.terminal import get_terminal_size
|
|
|
from IPython.utils import py3compat
|
|
|
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Classes and functions
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
esc_re = re.compile(r"(\x1b[^m]+m)")
|
|
|
|
|
|
def page_dumb(strng, start=0, screen_lines=25):
|
|
|
"""Very dumb 'pager' in Python, for when nothing else works.
|
|
|
|
|
|
Only moves forward, same interface as page(), except for pager_cmd and
|
|
|
mode."""
|
|
|
|
|
|
out_ln = strng.splitlines()[start:]
|
|
|
screens = chop(out_ln,screen_lines-1)
|
|
|
if len(screens) == 1:
|
|
|
print(os.linesep.join(screens[0]), file=io.stdout)
|
|
|
else:
|
|
|
last_escape = ""
|
|
|
for scr in screens[0:-1]:
|
|
|
hunk = os.linesep.join(scr)
|
|
|
print(last_escape + hunk, file=io.stdout)
|
|
|
if not page_more():
|
|
|
return
|
|
|
esc_list = esc_re.findall(hunk)
|
|
|
if len(esc_list) > 0:
|
|
|
last_escape = esc_list[-1]
|
|
|
print(last_escape + os.linesep.join(screens[-1]), file=io.stdout)
|
|
|
|
|
|
def _detect_screen_size(use_curses, screen_lines_def):
|
|
|
"""Attempt to work out the number of lines on the screen.
|
|
|
|
|
|
This is called by page(). It can raise an error (e.g. when run in the
|
|
|
test suite), so it's separated out so it can easily be called in a try block.
|
|
|
"""
|
|
|
TERM = os.environ.get('TERM',None)
|
|
|
if (TERM=='xterm' or TERM=='xterm-color') and sys.platform != 'sunos5':
|
|
|
local_use_curses = use_curses
|
|
|
else:
|
|
|
# curses causes problems on many terminals other than xterm, and
|
|
|
# some termios calls lock up on Sun OS5.
|
|
|
local_use_curses = False
|
|
|
if local_use_curses:
|
|
|
import termios
|
|
|
import curses
|
|
|
# There is a bug in curses, where *sometimes* it fails to properly
|
|
|
# initialize, and then after the endwin() call is made, the
|
|
|
# terminal is left in an unusable state. Rather than trying to
|
|
|
# check everytime for this (by requesting and comparing termios
|
|
|
# flags each time), we just save the initial terminal state and
|
|
|
# unconditionally reset it every time. It's cheaper than making
|
|
|
# the checks.
|
|
|
term_flags = termios.tcgetattr(sys.stdout)
|
|
|
|
|
|
# Curses modifies the stdout buffer size by default, which messes
|
|
|
# up Python's normal stdout buffering. This would manifest itself
|
|
|
# to IPython users as delayed printing on stdout after having used
|
|
|
# the pager.
|
|
|
#
|
|
|
# We can prevent this by manually setting the NCURSES_NO_SETBUF
|
|
|
# environment variable. For more details, see:
|
|
|
# http://bugs.python.org/issue10144
|
|
|
NCURSES_NO_SETBUF = os.environ.get('NCURSES_NO_SETBUF', None)
|
|
|
os.environ['NCURSES_NO_SETBUF'] = ''
|
|
|
|
|
|
# Proceed with curses initialization
|
|
|
scr = curses.initscr()
|
|
|
screen_lines_real,screen_cols = scr.getmaxyx()
|
|
|
curses.endwin()
|
|
|
|
|
|
# Restore environment
|
|
|
if NCURSES_NO_SETBUF is None:
|
|
|
del os.environ['NCURSES_NO_SETBUF']
|
|
|
else:
|
|
|
os.environ['NCURSES_NO_SETBUF'] = NCURSES_NO_SETBUF
|
|
|
|
|
|
# Restore terminal state in case endwin() didn't.
|
|
|
termios.tcsetattr(sys.stdout,termios.TCSANOW,term_flags)
|
|
|
# Now we have what we needed: the screen size in rows/columns
|
|
|
return screen_lines_real
|
|
|
#print '***Screen size:',screen_lines_real,'lines x',\
|
|
|
#screen_cols,'columns.' # dbg
|
|
|
else:
|
|
|
return screen_lines_def
|
|
|
|
|
|
def page(strng, start=0, screen_lines=0, pager_cmd=None):
|
|
|
"""Print a string, piping through a pager after a certain length.
|
|
|
|
|
|
The screen_lines parameter specifies the number of *usable* lines of your
|
|
|
terminal screen (total lines minus lines you need to reserve to show other
|
|
|
information).
|
|
|
|
|
|
If you set screen_lines to a number <=0, page() will try to auto-determine
|
|
|
your screen size and will only use up to (screen_size+screen_lines) for
|
|
|
printing, paging after that. That is, if you want auto-detection but need
|
|
|
to reserve the bottom 3 lines of the screen, use screen_lines = -3, and for
|
|
|
auto-detection without any lines reserved simply use screen_lines = 0.
|
|
|
|
|
|
If a string won't fit in the allowed lines, it is sent through the
|
|
|
specified pager command. If none given, look for PAGER in the environment,
|
|
|
and ultimately default to less.
|
|
|
|
|
|
If no system pager works, the string is sent through a 'dumb pager'
|
|
|
written in python, very simplistic.
|
|
|
"""
|
|
|
|
|
|
# Some routines may auto-compute start offsets incorrectly and pass a
|
|
|
# negative value. Offset to 0 for robustness.
|
|
|
start = max(0, start)
|
|
|
|
|
|
# first, try the hook
|
|
|
ip = ipapi.get()
|
|
|
if ip:
|
|
|
try:
|
|
|
ip.hooks.show_in_pager(strng)
|
|
|
return
|
|
|
except TryNext:
|
|
|
pass
|
|
|
|
|
|
# Ugly kludge, but calling curses.initscr() flat out crashes in emacs
|
|
|
TERM = os.environ.get('TERM','dumb')
|
|
|
if TERM in ['dumb','emacs'] and os.name != 'nt':
|
|
|
print(strng)
|
|
|
return
|
|
|
# chop off the topmost part of the string we don't want to see
|
|
|
str_lines = strng.splitlines()[start:]
|
|
|
str_toprint = os.linesep.join(str_lines)
|
|
|
num_newlines = len(str_lines)
|
|
|
len_str = len(str_toprint)
|
|
|
|
|
|
# Dumb heuristics to guesstimate number of on-screen lines the string
|
|
|
# takes. Very basic, but good enough for docstrings in reasonable
|
|
|
# terminals. If someone later feels like refining it, it's not hard.
|
|
|
numlines = max(num_newlines,int(len_str/80)+1)
|
|
|
|
|
|
screen_lines_def = get_terminal_size()[1]
|
|
|
|
|
|
# auto-determine screen size
|
|
|
if screen_lines <= 0:
|
|
|
try:
|
|
|
screen_lines += _detect_screen_size(use_curses, screen_lines_def)
|
|
|
except (TypeError, UnsupportedOperation):
|
|
|
print(str_toprint, file=io.stdout)
|
|
|
return
|
|
|
|
|
|
#print 'numlines',numlines,'screenlines',screen_lines # dbg
|
|
|
if numlines <= screen_lines :
|
|
|
#print '*** normal print' # dbg
|
|
|
print(str_toprint, file=io.stdout)
|
|
|
else:
|
|
|
# Try to open pager and default to internal one if that fails.
|
|
|
# All failure modes are tagged as 'retval=1', to match the return
|
|
|
# value of a failed system command. If any intermediate attempt
|
|
|
# sets retval to 1, at the end we resort to our own page_dumb() pager.
|
|
|
pager_cmd = get_pager_cmd(pager_cmd)
|
|
|
pager_cmd += ' ' + get_pager_start(pager_cmd,start)
|
|
|
if os.name == 'nt':
|
|
|
if pager_cmd.startswith('type'):
|
|
|
# The default WinXP 'type' command is failing on complex strings.
|
|
|
retval = 1
|
|
|
else:
|
|
|
tmpname = tempfile.mktemp('.txt')
|
|
|
tmpfile = open(tmpname,'wt')
|
|
|
tmpfile.write(strng)
|
|
|
tmpfile.close()
|
|
|
cmd = "%s < %s" % (pager_cmd,tmpname)
|
|
|
if os.system(cmd):
|
|
|
retval = 1
|
|
|
else:
|
|
|
retval = None
|
|
|
os.remove(tmpname)
|
|
|
else:
|
|
|
try:
|
|
|
retval = None
|
|
|
# if I use popen4, things hang. No idea why.
|
|
|
#pager,shell_out = os.popen4(pager_cmd)
|
|
|
pager = os.popen(pager_cmd, 'w')
|
|
|
try:
|
|
|
pager_encoding = pager.encoding or sys.stdout.encoding
|
|
|
pager.write(py3compat.cast_bytes_py2(
|
|
|
strng, encoding=pager_encoding))
|
|
|
finally:
|
|
|
retval = pager.close()
|
|
|
except IOError as msg: # broken pipe when user quits
|
|
|
if msg.args == (32, 'Broken pipe'):
|
|
|
retval = None
|
|
|
else:
|
|
|
retval = 1
|
|
|
except OSError:
|
|
|
# Other strange problems, sometimes seen in Win2k/cygwin
|
|
|
retval = 1
|
|
|
if retval is not None:
|
|
|
page_dumb(strng,screen_lines=screen_lines)
|
|
|
|
|
|
|
|
|
def page_file(fname, start=0, pager_cmd=None):
|
|
|
"""Page a file, using an optional pager command and starting line.
|
|
|
"""
|
|
|
|
|
|
pager_cmd = get_pager_cmd(pager_cmd)
|
|
|
pager_cmd += ' ' + get_pager_start(pager_cmd,start)
|
|
|
|
|
|
try:
|
|
|
if os.environ['TERM'] in ['emacs','dumb']:
|
|
|
raise EnvironmentError
|
|
|
system(pager_cmd + ' ' + fname)
|
|
|
except:
|
|
|
try:
|
|
|
if start > 0:
|
|
|
start -= 1
|
|
|
page(open(fname).read(),start)
|
|
|
except:
|
|
|
print('Unable to show file',repr(fname))
|
|
|
|
|
|
|
|
|
def get_pager_cmd(pager_cmd=None):
|
|
|
"""Return a pager command.
|
|
|
|
|
|
Makes some attempts at finding an OS-correct one.
|
|
|
"""
|
|
|
if os.name == 'posix':
|
|
|
default_pager_cmd = 'less -r' # -r for color control sequences
|
|
|
elif os.name in ['nt','dos']:
|
|
|
default_pager_cmd = 'type'
|
|
|
|
|
|
if pager_cmd is None:
|
|
|
try:
|
|
|
pager_cmd = os.environ['PAGER']
|
|
|
except:
|
|
|
pager_cmd = default_pager_cmd
|
|
|
return pager_cmd
|
|
|
|
|
|
|
|
|
def get_pager_start(pager, start):
|
|
|
"""Return the string for paging files with an offset.
|
|
|
|
|
|
This is the '+N' argument which less and more (under Unix) accept.
|
|
|
"""
|
|
|
|
|
|
if pager in ['less','more']:
|
|
|
if start:
|
|
|
start_string = '+' + str(start)
|
|
|
else:
|
|
|
start_string = ''
|
|
|
else:
|
|
|
start_string = ''
|
|
|
return start_string
|
|
|
|
|
|
|
|
|
# (X)emacs on win32 doesn't like to be bypassed with msvcrt.getch()
|
|
|
if os.name == 'nt' and os.environ.get('TERM','dumb') != 'emacs':
|
|
|
import msvcrt
|
|
|
def page_more():
|
|
|
""" Smart pausing between pages
|
|
|
|
|
|
@return: True if need print more lines, False if quit
|
|
|
"""
|
|
|
io.stdout.write('---Return to continue, q to quit--- ')
|
|
|
ans = msvcrt.getch()
|
|
|
if ans in ("q", "Q"):
|
|
|
result = False
|
|
|
else:
|
|
|
result = True
|
|
|
io.stdout.write("\b"*37 + " "*37 + "\b"*37)
|
|
|
return result
|
|
|
else:
|
|
|
def page_more():
|
|
|
ans = raw_input('---Return to continue, q to quit--- ')
|
|
|
if ans.lower().startswith('q'):
|
|
|
return False
|
|
|
else:
|
|
|
return True
|
|
|
|
|
|
|
|
|
def snip_print(str,width = 75,print_full = 0,header = ''):
|
|
|
"""Print a string snipping the midsection to fit in width.
|
|
|
|
|
|
print_full: mode control:
|
|
|
- 0: only snip long strings
|
|
|
- 1: send to page() directly.
|
|
|
- 2: snip long strings and ask for full length viewing with page()
|
|
|
Return 1 if snipping was necessary, 0 otherwise."""
|
|
|
|
|
|
if print_full == 1:
|
|
|
page(header+str)
|
|
|
return 0
|
|
|
|
|
|
print(header, end=' ')
|
|
|
if len(str) < width:
|
|
|
print(str)
|
|
|
snip = 0
|
|
|
else:
|
|
|
whalf = int((width -5)/2)
|
|
|
print(str[:whalf] + ' <...> ' + str[-whalf:])
|
|
|
snip = 1
|
|
|
if snip and print_full == 2:
|
|
|
if raw_input(header+' Snipped. View (y/n)? [N]').lower() == 'y':
|
|
|
page(str)
|
|
|
return snip
|
|
|
|
