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#! /usr/bin/env python3
# Copyright (c) 2015 by pyte authors and contributors
# Copyright (c) 2023 by Sebastian Pipping <sebastian@pipping.org>
#
# Licensed under LGPL v3, see pyte's LICENSE file for more details.
#
# Based on pyte's example "nanoterm.py"
# https://raw.githubusercontent.com/selectel/pyte/master/examples/nanoterm.py
# and a few lines from
# https://github.com/selectel/pyte/blob/master/pyte/screens.py
import enum
import os
import pty
import select
import signal
import sys
import time
from functools import lru_cache
from typing import Callable, Generator
import pyte
from pyte.screens import Char, StaticDefaultDict
from wcwidth import wcwidth as _wcwidth # type: ignore[import-untyped]
wcwidth: Callable[[str], int] = lru_cache(maxsize=4096)(_wcwidth) # from pyte/screens.py
class AnsiGraphics(enum.Enum):
# https://en.wikipedia.org/wiki/ANSI_escape_code#SGR_(Select_Graphic_Rendition)_parameters
RESET = 0
REVERSE = 7
def ansi_sequence(n):
# https://en.wikipedia.org/wiki/ANSI_escape_code#CSI_(Control_Sequence_Introducer)_sequences
return f'\033[{n.value}m'
def pyte_char_to_ansi(ch: Char) -> str:
"""
Render a single isolated ``pyte.screens.Char`` using ANSI escape sequences
https://pyte.readthedocs.io/en/latest/api.html#pyte.screens.Char
"""
chunks = []
if ch.reverse:
chunks.append(ansi_sequence(AnsiGraphics.RESET))
chunks.append(ansi_sequence(AnsiGraphics.REVERSE))
chunks.append(ch.data)
if ch.reverse:
chunks.append(ansi_sequence(AnsiGraphics.RESET))
return ''.join(chunks)
def ansi_display(screen):
"""
A (mostly identical) fork of ``pyte.screens.Screen.display``
that uses ``pyte_char_to_ansi`` rather than ``line[x].data``.
"""
def render(line: StaticDefaultDict[int, Char]) -> Generator[str, None, None]:
is_wide_char = False
for x in range(screen.columns):
if is_wide_char: # Skip stub
is_wide_char = False
continue
char = line[x].data
assert sum(map(wcwidth, char[1:])) == 0
is_wide_char = wcwidth(char[0]) == 2
yield pyte_char_to_ansi(line[x])
return ["".join(render(screen.buffer[y])) for y in range(screen.lines)]
def dump(screen, frame_number):
print(f'[{screen.columns}x{screen.lines}] Frame {frame_number}:')
print(f'+{"-" * screen.columns}+')
for line in ansi_display(screen):
print(f'|{line}|')
print(f'+{"-" * screen.columns}+')
print(flush=True)
def get_runtime_nanos():
return time.clock_gettime_ns(time.CLOCK_MONOTONIC)
def create_rhythmic_dumper(screen):
nano_before = get_runtime_nanos()
frame_number = 1
screen.dirty.clear()
def dump_or_not(last=False):
nonlocal nano_before
nonlocal frame_number
nano_now = get_runtime_nanos()
# For CI robustness, we want to:
# 1. Display 1 frame per second at most
# 2. Never display two identical consecutive frames
# 3. Only show an all-empty frame if it is not the first frame
# or the last frame
# 4. Always show at least one frame (overruling 3.)
if last or nano_now - nano_before >= 1_000_000_000:
if (frame_number == 1 and last) or (screen.dirty and not ((frame_number == 1 or last) and ''.join(ansi_display(screen)).isspace())):
dump(screen, frame_number=frame_number)
screen.dirty.clear()
frame_number += 1
nano_before = nano_now
return dump_or_not
if __name__ == "__main__":
if len(sys.argv) <= 1:
progname_py = os.path.basename(sys.argv[0])
sys.exit(f'usage: python3 {progname_py} COMMAND [ARG ..]')
COLUMNS = 90
LINES = 20
screen = pyte.Screen(COLUMNS, LINES)
stream = pyte.ByteStream(screen)
dump_or_not = create_rhythmic_dumper(screen)
p_pid, master_fd = pty.fork()
if p_pid == 0: # Child.
env = os.environ.copy()
env.update(dict(TERM="linux", COLUMNS=str(COLUMNS), LINES=str(LINES)))
os.execvpe(sys.argv[1], sys.argv[1:], env=env)
while True:
try:
readables, _w, _x = select.select(
[master_fd], [], [], 0.1)
except (KeyboardInterrupt, # Stop right now!
ValueError): # Nothing to read.
break
dump_or_not()
if not readables:
continue
try:
data = os.read(master_fd, 1024)
except OSError:
break
if not data:
break
stream.feed(data)
dump_or_not()
os.kill(p_pid, signal.SIGTERM)
dump_or_not(last=True)
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