146 lines
4.9 KiB
Python
146 lines
4.9 KiB
Python
# Copyright 2020 Canonical, Ltd.
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import fcntl
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import logging
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import os
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import sys
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import tty
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import urwid
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from subiquitycore.palette import COLORS, urwid_8_names
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log = logging.getLogger("subiquitycore.screen")
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# From uapi/linux/kd.h:
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KDGKBTYPE = 0x4B33 # get keyboard type
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GIO_CMAP = 0x4B70 # gets colour palette on VGA+
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PIO_CMAP = 0x4B71 # sets colour palette on VGA+
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UO_R, UO_G, UO_B = 0xE9, 0x54, 0x20
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class SubiquityScreen(urwid.raw_display.Screen):
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# This class fixes a bug in urwid's screen:
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#
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# Calling screen.stop() sends the INPUT_DESCRIPTORS_CHANGED signal. This
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# calls _reset_input_descriptors() which calls unhook_event_loop /
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# hook_event_loop on the screen. But this all happens before _started is
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# set to False on the screen and so this does not actually do anything. If
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# we call stop and then, for example, run bash, we end up attempting to
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# read from stdin while in a background process group and that gets the
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# kernel upset at us.
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#
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# The cleanest fix seems to be to just send the signal again once stop()
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# has returned which, now that screen._started is False, correctly stops
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# listening from stdin.
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#
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# There is an exactly analagous problem with screen.start() except there
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# the symptom is that we are running in the foreground but not listening to
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# stdin! The fix is the same.
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def start(self):
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super().start()
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urwid.emit_signal(self, urwid.display_common.INPUT_DESCRIPTORS_CHANGED)
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# We run the terminal in raw, not cbreak mode.
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fd = self._term_input_file.fileno()
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if os.isatty(fd):
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tty.setraw(fd)
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def stop(self):
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super().stop()
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urwid.emit_signal(self, urwid.display_common.INPUT_DESCRIPTORS_CHANGED)
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class LinuxScreen(SubiquityScreen):
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def __init__(self, colors, **kwargs):
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self._colors = colors
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super().__init__(**kwargs)
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def start(self):
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self.curpal = bytearray(16 * 3)
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fcntl.ioctl(sys.stdout.fileno(), GIO_CMAP, self.curpal)
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newpal = self.curpal.copy()
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for i in range(8):
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for j in range(3):
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newpal[i * 3 + j] = self._colors[i][1][j]
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fcntl.ioctl(self._term_input_file.fileno(), PIO_CMAP, newpal)
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super().start()
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def stop(self):
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fcntl.ioctl(self._term_input_file.fileno(), PIO_CMAP, self.curpal)
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super().stop()
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class TwentyFourBitScreen(SubiquityScreen):
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def __init__(self, colors, **kwargs):
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self._urwid_name_to_rgb = {n: colors[i][1] for i, n in enumerate(urwid_8_names)}
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super().__init__(**kwargs)
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def _cc(self, color):
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"""Return the "SGR" parameter for selecting color.
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See https://en.wikipedia.org/wiki/ANSI_escape_code#SGR for an
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explanation. We use the basic codes for black/white/default for
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maximum compatibility; they are the only colors used when the
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mono palette is selected.
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"""
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if color == "white":
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return "7"
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elif color == "black":
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return "0"
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elif color == "default":
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return "9"
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else:
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# This is almost but not quite a ISO 8613-3 code -- that
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# would use colons to separate the rgb values instead. But
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# it's what xterm, and hence everything else, supports.
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return "8;2;{};{};{}".format(*self._urwid_name_to_rgb[color])
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def _attrspec_to_escape(self, a):
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return "\x1b[0;3{};4{}m".format(self._cc(a.foreground), self._cc(a.background))
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_is_linux_tty = None
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def is_linux_tty():
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global _is_linux_tty
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if _is_linux_tty is None:
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try:
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r = fcntl.ioctl(sys.stdout.fileno(), KDGKBTYPE, " ")
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except IOError as e:
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log.debug("KDGKBTYPE failed %r", e)
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return False
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log.debug("KDGKBTYPE returned %r, is_linux_tty %s", r, r == b"\x02")
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_is_linux_tty = r == b"\x02"
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return _is_linux_tty
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def make_screen(ascii=False, inputf=None, outputf=None):
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""" """
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if inputf is None:
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inputf = sys.stdin
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if outputf is None:
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outputf = sys.stdout
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if is_linux_tty():
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return LinuxScreen(COLORS, input=inputf, output=outputf)
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elif ascii:
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return SubiquityScreen(input=inputf, output=outputf)
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else:
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return TwentyFourBitScreen(COLORS, input=inputf, output=outputf)
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