# The MIT License

#

# Copyright (c) 2009-2011 Andreas Stuehrk

#

# Permission is hereby granted, free of charge, to any person obtaining a copy

# of this software and associated documentation files (the "Software"), to deal

# in the Software without restriction, including without limitation the rights

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

# copies of the Software, and to permit persons to whom the Software is

# furnished to do so, subject to the following conditions:

#

# The above copyright notice and this permission notice shall be included in

# all copies or substantial portions of the Software.

#

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

# THE SOFTWARE.

# mypy: disallow_untyped_defs=True

# mypy: disallow_untyped_calls=True

import curses

import errno

import os

import pydoc

import subprocess

import sys

import shlex

def get_pager_command(default: str = "less -rf") -> list[str]:

return shlex.split(os.environ.get("PAGER", default))

def page_internal(data: str) -> None:

"""A more than dumb pager function."""

if hasattr(pydoc, "ttypager"):

pydoc.ttypager(data)

else:

sys.stdout.write(data)

def page(data: str, use_internal: bool = False) -> None:

command = get_pager_command()

if not command or use_internal:

page_internal(data)

else:

curses.endwin()

try:

popen = subprocess.Popen(command, stdin=subprocess.PIPE)

assert popen.stdin is not None

# `encoding` is new in py39

data_bytes = data.encode(sys.__stdout__.encoding, "replace") # type: ignore

popen.stdin.write(data_bytes)

popen.stdin.close()

except OSError as e:

if e.errno == errno.ENOENT:

# pager command not found, fall back to internal pager

page_internal(data)

return

if e.errno != errno.EPIPE:

raise

while True:

try:

popen.wait()

except OSError as e:

if e.errno != errno.EINTR:

raise

else:

break

curses.doupdate()

# vim: sw=4 ts=4 sts=4 ai et