"""
Terminal-related utilities
--------------------------
"""
import contextlib
import os
import sys
from typing import List, Optional
from plumbum import local
from .progress import Progress
from .termsize import get_terminal_size
__all__ = [
"readline",
"ask",
"choose",
"prompt",
"get_terminal_size",
"Progress",
"get_terminal_size",
]
def __dir__() -> List[str]:
return __all__
[docs]def readline(message: str = "") -> str:
"""Gets a line of input from the user (stdin)"""
sys.stdout.write(message)
sys.stdout.flush()
return sys.stdin.readline()
[docs]def ask(question: str, default: Optional[bool] = None) -> bool:
"""
Presents the user with a yes/no question.
:param question: The question to ask
:param default: If ``None``, the user must answer. If ``True`` or ``False``, lack of response is
interpreted as the default option
:returns: the user's choice
"""
question = question.rstrip().rstrip("?").rstrip() + "?"
if default is None:
question += " (y/n) "
elif default:
question += " [Y/n] "
else:
question += " [y/N] "
while True:
try:
answer = readline(question).strip().lower()
except EOFError:
answer = None
if answer in {"y", "yes"}:
return True
if answer in {"n", "no"}:
return False
if not answer and default is not None:
return default
sys.stdout.write("Invalid response, please try again\n")
[docs]def choose(question, options, default=None):
"""Prompts the user with a question and a set of options, from which the user needs to choose.
:param question: The question to ask
:param options: A set of options. It can be a list (of strings or two-tuples, mapping text
to returned-object) or a dict (mapping text to returned-object).``
:param default: If ``None``, the user must answer. Otherwise, lack of response is interpreted
as this answer
:returns: The user's choice
Example::
ans = choose("What is your favorite color?", ["blue", "yellow", "green"], default = "yellow")
# `ans` will be one of "blue", "yellow" or "green"
ans = choose("What is your favorite color?",
{"blue" : 0x0000ff, "yellow" : 0xffff00 , "green" : 0x00ff00}, default = 0x00ff00)
# this will display "blue", "yellow" and "green" but return a numerical value
"""
if hasattr(options, "items"):
options = options.items()
sys.stdout.write(question.rstrip() + "\n")
choices = {}
defindex = None
for i, item in enumerate(options, 1):
if isinstance(item, (tuple, list)) and len(item) == 2:
text = item[0]
val = item[1]
else:
text = item
val = item
choices[i] = val
if default is not None and default == val:
defindex = i
sys.stdout.write(f"({i}) {text}\n")
if default is not None:
msg = f"Choice [{default}]: " if defindex is None else f"Choice [{defindex}]: "
else:
msg = "Choice: "
while True:
try:
choice = readline(msg).strip()
except EOFError:
choice = ""
if not choice and default:
return default
try:
choice = int(choice)
if choice not in choices:
raise ValueError()
except ValueError:
sys.stdout.write("Invalid choice, please try again\n")
continue
return choices[choice]
[docs]def prompt(
question,
type=str, # pylint: disable=redefined-builtin
default=NotImplemented,
validator=lambda _: True,
):
"""
Presents the user with a validated question, keeps asking if validation does not pass.
:param question: The question to ask
:param type: The type of the answer, defaults to str
:param default: The default choice
:param validator: An extra validator called after type conversion, can raise ValueError or return False to trigger a retry.
:returns: the user's choice
"""
question = question.rstrip(" \t:")
if default is not NotImplemented:
question += f" [{default}]"
question += ": "
while True:
try:
ans = readline(question).strip()
except EOFError:
ans = ""
if not ans:
if default is not NotImplemented:
# sys.stdout.write("\b%s\n" % (default,))
return default
continue
try:
ans = type(ans)
except (TypeError, ValueError) as ex:
sys.stdout.write(f"Invalid value ({ex}), please try again\n")
continue
try:
valid = validator(ans)
except ValueError as ex:
sys.stdout.write(f"{ex}, please try again\n")
continue
if not valid:
sys.stdout.write("Value not in specified range, please try again\n")
continue
return ans
def hexdump(data_or_stream, bytes_per_line=16, aggregate=True):
"""Convert the given bytes (or a stream with a buffering ``read()`` method) to hexdump-formatted lines,
with possible aggregation of identical lines. Returns a generator of formatted lines.
"""
if hasattr(data_or_stream, "read"):
def read_chunk():
while True:
buf = data_or_stream.read(bytes_per_line)
if not buf:
break
yield buf
else:
def read_chunk():
for i in range(0, len(data_or_stream), bytes_per_line):
yield data_or_stream[i : i + bytes_per_line]
prev = None
skipped = False
for i, chunk in enumerate(read_chunk()):
hexd = " ".join(f"{ord(ch):02x}" for ch in chunk)
text = "".join(ch if 32 <= ord(ch) < 127 else "." for ch in chunk)
if aggregate and prev == chunk:
skipped = True
continue
prev = chunk
if skipped:
yield "*"
hexd_ljust = hexd.ljust(bytes_per_line * 3, " ")
yield f"{i*bytes_per_line:06x} | {hexd_ljust}| {text}"
skipped = False
def pager(rows, pagercmd=None): # pragma: no cover
"""Opens a pager (e.g., ``less``) to display the given text. Requires a terminal.
:param rows: a ``bytes`` or a list/iterator of "rows" (``bytes``)
:param pagercmd: the pager program to run. Defaults to ``less -RSin``
"""
if not pagercmd:
pagercmd = local["less"]["-RSin"]
if hasattr(rows, "splitlines"):
rows = rows.splitlines()
pg = pagercmd.popen(stdout=None, stderr=None)
try:
for row in rows:
line = f"{row}\n"
try:
pg.stdin.write(line)
pg.stdin.flush()
except OSError:
break
pg.stdin.close()
pg.wait()
finally:
with contextlib.suppress(Exception):
rows.close()
if pg and pg.poll() is None:
with contextlib.suppress(Exception):
pg.terminate()
os.system("reset")
