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Python

# Urwid utility functions
# Copyright (C) 2004-2011 Ian Ward
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Urwid web site: https://urwid.org/
from __future__ import annotations
import codecs
import contextlib
import sys
import typing
import warnings
from contextlib import suppress
from urwid import str_util
if typing.TYPE_CHECKING:
from collections.abc import Generator, Iterable
from types import TracebackType
from typing_extensions import Literal, Protocol, Self
class CanBeStopped(Protocol):
def stop(self) -> None: ...
def __getattr__(name: str) -> typing.Any:
if hasattr(str_util, name):
warnings.warn(
f"Do not import {name!r} from {__package__}.{__name__}, import it from 'urwid'.",
DeprecationWarning,
stacklevel=3,
)
return getattr(str_util, name)
raise AttributeError(f"{name} is not defined in {__package__}.{__name__}")
def detect_encoding() -> str:
# Windows is a special case:
# CMD is Unicode and non-unicode at the same time:
# Unicode display support depends on C API usage and partially limited by font settings.
# By default, python is distributed in "Unicode" version, and since Python version 3.8 only Unicode.
# In case of curses, "windows-curses" is distributed in unicode-only.
# Since Windows 10 default console font is already unicode,
# in older versions maybe need to set TTF font manually to support more symbols
# (this does not affect unicode IO).
if sys.platform == "win32" and sys.getdefaultencoding() == "utf-8":
return "utf-8"
# Try to determine if using a supported double-byte encoding
import locale
no_set_locale = locale.getpreferredencoding(False)
if no_set_locale != "ascii":
# ascii is fallback locale in case of detect failed
return no_set_locale
# Use actual `getpreferredencoding` with public API only
old_loc = locale.setlocale(locale.LC_CTYPE) # == getlocale, but not mangle data
try:
with suppress(locale.Error):
locale.setlocale(locale.LC_CTYPE, "")
# internally call private `_get_locale_encoding`
return locale.getpreferredencoding(False)
finally:
with suppress(locale.Error):
locale.setlocale(locale.LC_CTYPE, old_loc)
if "detected_encoding" not in locals():
detected_encoding = detect_encoding()
else:
raise RuntimeError("Encoding detection broken")
_target_encoding = "ascii"
_use_dec_special = True
def set_encoding(encoding: str) -> None:
"""
Set the byte encoding to assume when processing strings and the
encoding to use when converting unicode strings.
"""
encoding = encoding.lower()
global _target_encoding, _use_dec_special # noqa: PLW0603 # noqa: PLW0603 # pylint: disable=global-statement
if encoding in {"utf-8", "utf8", "utf"}:
str_util.set_byte_encoding("utf8")
_use_dec_special = False
elif encoding in {
"euc-jp", # JISX 0208 only
"euc-kr",
"euc-cn",
"euc-tw", # CNS 11643 plain 1 only
"gb2312",
"gbk",
"big5",
"cn-gb",
"uhc",
# these shouldn't happen, should they?
"eucjp",
"euckr",
"euccn",
"euctw",
"cncb",
}:
str_util.set_byte_encoding("wide")
_use_dec_special = True
else:
str_util.set_byte_encoding("narrow")
_use_dec_special = True
# if encoding is valid for conversion from unicode, remember it
_target_encoding = "ascii"
with contextlib.suppress(LookupError):
if encoding:
"".encode(encoding)
_target_encoding = encoding
def get_encoding() -> str:
"""Get target encoding."""
return _target_encoding
@contextlib.contextmanager
def set_temporary_encoding(encoding_name: str) -> Generator[None]:
"""Internal helper for encoding specific validation in unittests/doctests.
Not exported globally.
"""
old_encoding = _target_encoding
try:
set_encoding(encoding_name)
yield
finally:
set_encoding(old_encoding)
def get_encoding_mode() -> Literal["wide", "narrow", "utf8"]:
"""
Get the mode Urwid is using when processing text strings.
Returns 'narrow' for 8-bit encodings, 'wide' for CJK encodings
or 'utf8' for UTF-8 encodings.
"""
return str_util.get_byte_encoding()
def apply_target_encoding(s: str | bytes) -> tuple[bytes, list[tuple[Literal["U", "0"] | None, int]]]:
"""
Return (encoded byte string, character set rle).
"""
# Import locally to warranty no circular imports
from urwid.display import escape
if _use_dec_special and isinstance(s, str):
# first convert drawing characters
s = s.translate(escape.DEC_SPECIAL_CHARMAP)
if isinstance(s, str):
s = s.replace(escape.SI + escape.SO, "") # remove redundant shifts
s = codecs.encode(s, _target_encoding, "replace")
if not isinstance(s, bytes):
raise TypeError(s)
SO = escape.SO.encode("ascii")
SI = escape.SI.encode("ascii")
sis = s.split(SO)
sis0 = sis[0].replace(SI, b"")
sout = []
cout = []
if sis0:
sout.append(sis0)
cout.append((None, len(sis0)))
if len(sis) == 1:
return sis0, cout
for sn in sis[1:]:
sl = sn.split(SI, 1)
if len(sl) == 1:
sin = sl[0]
sout.append(sin)
rle_append_modify(cout, (escape.DEC_TAG, len(sin)))
continue
sin, son = sl
son = son.replace(SI, b"")
if sin:
sout.append(sin)
rle_append_modify(cout, (escape.DEC_TAG, len(sin)))
if son:
sout.append(son)
rle_append_modify(cout, (None, len(son)))
outstr = b"".join(sout)
return outstr, cout
######################################################################
# Try to set the encoding using the one detected by the locale module
set_encoding(detected_encoding)
######################################################################
def supports_unicode() -> bool:
"""
Return True if python is able to convert non-ascii unicode strings
to the current encoding.
"""
return _target_encoding and _target_encoding != "ascii"
def calc_trim_text(
text: str | bytes,
start_offs: int,
end_offs: int,
start_col: int,
end_col: int,
) -> tuple[int, int, int, int]:
"""
Calculate the result of trimming text.
start_offs -- offset into text to treat as screen column 0
end_offs -- offset into text to treat as the end of the line
start_col -- screen column to trim at the left
end_col -- screen column to trim at the right
Returns (start, end, pad_left, pad_right), where:
start -- resulting start offset
end -- resulting end offset
pad_left -- 0 for no pad or 1 for one space to be added
pad_right -- 0 for no pad or 1 for one space to be added
"""
spos = start_offs
pad_left = pad_right = 0
if start_col > 0:
spos, sc = str_util.calc_text_pos(text, spos, end_offs, start_col)
if sc < start_col:
pad_left = 1
spos, sc = str_util.calc_text_pos(text, start_offs, end_offs, start_col + 1)
run = end_col - start_col - pad_left
pos, sc = str_util.calc_text_pos(text, spos, end_offs, run)
if sc < run:
pad_right = 1
return (spos, pos, pad_left, pad_right)
def trim_text_attr_cs(text: bytes, attr, cs, start_col: int, end_col: int):
"""
Return ( trimmed text, trimmed attr, trimmed cs ).
"""
spos, epos, pad_left, pad_right = calc_trim_text(text, 0, len(text), start_col, end_col)
attrtr = rle_subseg(attr, spos, epos)
cstr = rle_subseg(cs, spos, epos)
if pad_left:
al = rle_get_at(attr, spos - 1)
rle_prepend_modify(attrtr, (al, 1))
rle_prepend_modify(cstr, (None, 1))
if pad_right:
al = rle_get_at(attr, epos)
rle_append_modify(attrtr, (al, 1))
rle_append_modify(cstr, (None, 1))
return (b"".rjust(pad_left) + text[spos:epos] + b"".rjust(pad_right), attrtr, cstr)
def rle_get_at(rle, pos: int):
"""
Return the attribute at offset pos.
"""
x = 0
if pos < 0:
return None
for a, run in rle:
if x + run > pos:
return a
x += run
return None
def rle_subseg(rle, start: int, end: int):
"""Return a sub segment of a rle list."""
sub_segment = []
x = 0
for a, run in rle:
if start:
if start >= run:
start -= run
x += run
continue
x += start
run -= start # noqa: PLW2901
start = 0
if x >= end:
break
if x + run > end:
run = end - x # noqa: PLW2901
x += run
sub_segment.append((a, run))
return sub_segment
def rle_len(rle: Iterable[tuple[typing.Any, int]]) -> int:
"""
Return the number of characters covered by a run length
encoded attribute list.
"""
run = 0
for v in rle:
if not isinstance(v, tuple):
raise TypeError(rle)
_a, r = v
run += r
return run
def rle_prepend_modify(rle, a_r) -> None:
"""
Append (a, r) (unpacked from *a_r*) to BEGINNING of rle.
Merge with first run when possible
MODIFIES rle parameter contents. Returns None.
"""
a, r = a_r
if not rle:
rle[:] = [(a, r)]
else:
al, run = rle[0]
if a == al:
rle[0] = (a, run + r)
else:
rle[0:0] = [(a, r)]
def rle_append_modify(rle, a_r) -> None:
"""
Append (a, r) (unpacked from *a_r*) to the rle list rle.
Merge with last run when possible.
MODIFIES rle parameter contents. Returns None.
"""
a, r = a_r
if not rle or rle[-1][0] != a:
rle.append((a, r))
return
_la, lr = rle[-1]
rle[-1] = (a, lr + r)
def rle_join_modify(rle, rle2) -> None:
"""
Append attribute list rle2 to rle.
Merge last run of rle with first run of rle2 when possible.
MODIFIES attr parameter contents. Returns None.
"""
if not rle2:
return
rle_append_modify(rle, rle2[0])
rle += rle2[1:]
def rle_product(rle1, rle2):
"""
Merge the runs of rle1 and rle2 like this:
eg.
rle1 = [ ("a", 10), ("b", 5) ]
rle2 = [ ("Q", 5), ("P", 10) ]
rle_product: [ (("a","Q"), 5), (("a","P"), 5), (("b","P"), 5) ]
rle1 and rle2 are assumed to cover the same total run.
"""
i1 = i2 = 1 # rle1, rle2 indexes
if not rle1 or not rle2:
return []
a1, r1 = rle1[0]
a2, r2 = rle2[0]
result = []
while r1 and r2:
r = min(r1, r2)
rle_append_modify(result, ((a1, a2), r))
r1 -= r
if r1 == 0 and i1 < len(rle1):
a1, r1 = rle1[i1]
i1 += 1
r2 -= r
if r2 == 0 and i2 < len(rle2):
a2, r2 = rle2[i2]
i2 += 1
return result
def rle_factor(rle):
"""
Inverse of rle_product.
"""
rle1 = []
rle2 = []
for (a1, a2), r in rle:
rle_append_modify(rle1, (a1, r))
rle_append_modify(rle2, (a2, r))
return rle1, rle2
class TagMarkupException(Exception):
pass
def decompose_tagmarkup(tm):
"""Return (text string, attribute list) for tagmarkup passed."""
tl, al = _tagmarkup_recurse(tm, None)
# join as unicode or bytes based on type of first element
if tl:
text = tl[0][:0].join(tl)
else:
text = ""
if al and al[-1][0] is None:
del al[-1]
return text, al
def _tagmarkup_recurse(tm, attr):
"""Return (text list, attribute list) for tagmarkup passed.
tm -- tagmarkup
attr -- current attribute or None"""
if isinstance(tm, list):
# for lists recurse to process each subelement
rtl = []
ral = []
for element in tm:
tl, al = _tagmarkup_recurse(element, attr)
if ral:
# merge attributes when possible
last_attr, last_run = ral[-1]
top_attr, top_run = al[0]
if last_attr == top_attr:
ral[-1] = (top_attr, last_run + top_run)
del al[0]
rtl += tl
ral += al
return rtl, ral
if isinstance(tm, tuple):
# tuples mark a new attribute boundary
if len(tm) != 2:
raise TagMarkupException(f"Tuples must be in the form (attribute, tagmarkup): {tm!r}")
attr, element = tm
return _tagmarkup_recurse(element, attr)
if not isinstance(tm, (str, bytes)):
raise TagMarkupException(f"Invalid markup element: {tm!r}")
# text
return [tm], [(attr, len(tm))]
def is_mouse_event(ev: tuple[str, int, int, int] | typing.Any) -> bool:
return isinstance(ev, tuple) and len(ev) == 4 and "mouse" in ev[0]
def is_mouse_press(ev: str) -> bool:
return "press" in ev
class MetaSuper(type):
"""adding .__super"""
def __init__(cls, name: str, bases, d):
super().__init__(name, bases, d)
if hasattr(cls, f"_{name}__super"):
raise AttributeError("Class has same name as one of its super classes")
@property
def _super(self):
warnings.warn(
f"`{name}.__super` was a deprecated feature for old python versions."
f"Please use `super()` call instead.",
DeprecationWarning,
stacklevel=3,
)
return super(cls, self)
setattr(cls, f"_{name}__super", _super)
def int_scale(val: int, val_range: int, out_range: int) -> int:
"""
Scale val in the range [0, val_range-1] to an integer in the range
[0, out_range-1]. This implementation uses the "round-half-up" rounding
method.
>>> "%x" % int_scale(0x7, 0x10, 0x10000)
'7777'
>>> "%x" % int_scale(0x5f, 0x100, 0x10)
'6'
>>> int_scale(2, 6, 101)
40
>>> int_scale(1, 3, 4)
2
"""
num = int(val * (out_range - 1) * 2 + (val_range - 1))
dem = (val_range - 1) * 2
# if num % dem == 0 then we are exactly half-way and have rounded up.
return num // dem
class StoppingContext(typing.ContextManager["StoppingContext"]):
"""Context manager that calls ``stop`` on a given object on exit. Used to
make the ``start`` method on `MainLoop` and `BaseScreen` optionally act as
context managers.
"""
__slots__ = ("_wrapped",)
def __init__(self, wrapped: CanBeStopped) -> None:
self._wrapped = wrapped
def __enter__(self) -> Self:
return self
def __exit__(
self,
exc_type: type[BaseException] | None,
exc_val: BaseException | None,
exc_tb: TracebackType | None,
) -> None:
self._wrapped.stop()